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# Matrix Converter Applications

With help of this calculator you can: find the matrix determinant, the rank, raise the matrix to a power, find the sum and the multiplication of matrices, calculate the inverse matrix. They're more often called program files, but either way, they don't necessarily have anything to do with the. It's great if you use ALG48. The data encoded in a. Applications range from computers, pumps, welders, ovens, to CNC mills, etc. Table 1 and 2 shows the com-position and properties of both the matrix and the reinforcement. The bidirectional switches were initially obtained combining discrete components [8]. INTRODUCTION Real development of matrix converters starts with the work of Venturini and Alesina published in 1980. 0, the matrix is exactly the "convert to luminance" matrix described above. In many applications, such as flat panel TVs, 85+ ATX PCs or small form factor PCs, where the. To Practice. Description. Open-end winding induction motor drive based on matrix converters. Induction Motor Using 1ᛰMatrix Converter"in special issue of IJCTA,9(29),2016,pp. the single phase matrix converter switching arrangement. How to Convert an ARF File ARF is a pretty specific file format that makes it really hard to use in other applications or to upload and use with online services like YouTube or Dropbox. Free matrix equations calculator - solve matrix equations step-by-step Derivatives Derivative Applications Limits Integrals Integral Applications Series ODE. Works in HP 48 G/G+/GX, as far as I know. It should be •“straight” and pass through the end points. The difference between it and the kind of matrix operations I was used to in the 3D graphics world is that the matrices it works on are often very big. DURAGESIC ® is:. Integration of Matrix Converter with DTC of Induction Motor Drive Applications Patra Venkaiah 1, Tegala. Conventional Direct Matrix Converters (Fig. This Application Note describes how to examine the network and look for the multicast sources on the network. This would not of course be an issue for a custom solution such as an integrated motor drive, where the motor winding voltage could be selected. Operations on vectors - addition, multiplication by a number. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The matrix converter has several advantages over traditional rectifier-inverter. evalcenter - VMware VMware. It is important to notice that while calculating using Gauss-Jordan calculator if a matrix has at least one zero row with NONzero right hand side (column of constant terms) the system of equations is inconsistent then. ; Delphi Trusted for over 23 years, our modern Delphi is the preferred choice of Object Pascal developers worldwide for creating cool apps across devices. Access the Catalog in the TI-Nspire Calculator application. Moody’s CreditView is our flagship solution for global capital markets that incorporates credit ratings, research and data from Moody’s Investors Service plus research, data and content from Moody’s Analytics. Subsequently, atoms and molecules are raised to excited states via thermal collisions with the. Spring IDX Agent All-In-One Websites, WordPress IDX Plugin or SmartFrames. In this case the code is pretty compact. It should be •“straight” and pass through the end points. In Google Analytics we can find some touchpoints more likely to assist to conversion than others that more likely to be last-click touchpoint. Three-phase full wave converter. A common operation that reduces the size of large 24 bit bitmaps is to convert them to indexed colour with an optimised palette, that is, a palette which best represents the colours available in the bitmap. Buy Applications Converters Matrix Converters from eBay and save. Guided by that affiliation, BYU-Idaho seeks to create a wholesome learning environment in which students can strengthen their commitment to their faith and receive a quality education that prepares them for leadership in the home, the community, and the workplace. The vector modulation and the current commutation strategies of a matrix converter are described. However, you can solve for the determinant of a 4-by-4 matrix by replacing the values in the rows and using the "upper triangular" form of matrices. The free version of this product includes a watermark under the barcode. Used by over 7,000,000 students, IXL provides personalized learning in more than 8,000 topics, covering math, language arts, science, social studies, and Spanish. 6 shows that generation of pulse width modulation gate signal using MATLAB. The Modular Multilevel Matrix Converter (M3C) performs a direct three-phase AC to AC power conversion and is highly suitable for medium voltage high power drive applications. Oracle Applications Unlimited gives you the option to do what is best for your business: continue to derive value from your existing applications or upgrade to next-generation Oracle Applications, such as those built on Oracle Fusion Middleware, when it makes business sense. org and Google Sheets. G Student Scholar, Department of Electrical & Electronics Engineering , Avanti Institute of Engineering & Technology, Makavaripalem(P),Vishakhapatnam(Dt) , Andhra Pradesh, India 1. Distributing Python Modules publishing modules for installation by others. Observer Matrix Matrix Matrix CLI nTAPs Overview, FAQ, Attenuation Optical Optical 40 Gb Multimode High Density Optical Copper-to-Optical Conversion Optical-to. This converter can be connected to different loads such as RL and RLE loads. Replicating the method for Sepic Converter and doing a comparative performance analysis in open loop and closed loop configuration using MATLAB®/SIMULINK • Preparing a small signal matrix by. The remaining lower-right-most components of the source matrix are lost. The California Air Resources Board typically has monthly meetings with the agenda available at least 10 days prior to the meeting date. 5 - Applications of Matrices and Determinants Area of a Triangle. Undirected graphs representation. This calculator is designed to calculate $2\times 2$, $3\times3$ and $4\times 4$ matrix determinant value. This is an example of a normalized metric. Leave extra cells empty to enter non-square matrices. 00 per page recording fee in addition to the filing fee. The converter without dc link will be preferred over the two stage ac-dc-ac conversion in the existing power conversion arrangements in the ac traction drives. This study focuses on three-phase power switching through the development of an experimental setup which consists of a three-phase direct AC/AC matrix converter with a power. Matrix Converter (H 3Ø) Matrix Converters (H 1Ø) High Frequency Transformer Figure 1 - Power Electronic Transformer for Electric Traction The Matrix Converter (MC), which received significant improvements in recent years [3], is a power electronic converter with high frequency switching that generates a. This white paper is intended as a tool to help system designers choose the best DC-DC switching converter for their application. Abstract: The matrix converter is an array of controlled semiconductor switches that connects directly the three-phase source to the three-phase load. Open-end winding induction motor drive based on matrix converters. 3% at 60 V and 48 V input respectively, and maintains high efficiency over a wide operating range. Pulse width modulation (PWM) to control the switching sequence is used for the conversion process. Presently, in spite of several challenges, it is growing rapidly to achieve 760 GW by the year 2020. The Texas Common Course Numbering System (TCCNS) is a voluntary, co-operative effort among 137 Texas community colleges and universities to facilitate transfer of freshman and sophomore level general academic coursework. A Fundamental Verification of a Single-phase to Three-phase Matrix Converter with a PDM Control based on Space Vector Modulation Yuki Nakata and Jun-ichi Itoh Department of Electrical, Electronics and Information Engineering Nagaoka University of Technology Nagaoka, Niigata, Japan [email protected] If you're unable to use a photo, graphic, or any kind of image file the way you'd like because the format isn't supported, image converter software can help. : TECHNOLOGICAL ISSUES AND INDUSTRIAL APPLICATION OF MATRIX CONVERTERS 4261 Fig. Read about how we use cookies and how you can control them here. In ROS applications, the rotation of a robot or link is generally described by 4 quaternion numbers. This is done by describing all the above-mentioned metrics and providing a procedure for optimum choice. The number of PVU entitlements required is based on the processor technology (defined within the PVU Table above by Processor Vendor, Brand, Type and Model Number) and by the number of processors made available to the Program. Jump start your school, work, or family project and save time with a professionally designed Word, Excel, PowerPoint template that’s a perfect fit. Accenture’s enterprise cloud application services’ experience and capabilities. and you can convert between less obviously related structures, such as from a matrix to a set. The 16 pins of the matrix are hooked up to 16 pins of the Arduino or Genuino board. If you ever ask yourself how to convert images to characters or to binary. Simple AC to AC Converter. Go digital with DocuSign. Learn online and earn credentials from top universities like Yale, Michigan, Stanford, and leading companies like Google and IBM. Understanding matrix is important to solve linear equations using matrices. An indeﬁnite quadratic form will notlie completely above or below the plane but will lie above for somevalues of x and belowfor other values of x. The AC7 is the world's first low voltage (230V/460V) matrix converter to directly convert input AC voltage to output AC voltage without the need for a DC Bus. Online homework and grading tools for instructors and students that reinforce student learning through practice and instant feedback. Mathematics Applied to Physics and Engineering Applications and Use of the Inverse Functions. You’ll have Office applications on your Mac or PC, apps on tablets and smartphones for when you're on the go, and Office Online on the web for everywhere in between. In wind power a generator is driven by wind, thus the resulting power is of widely varying frequency and amplitude. Matrix algebra. Inlite's Barcode scanner software is the best barcode recognition solution for your product, Web Site or IT department. Click icon to show file QR code or save file to online storage services such as Google Drive or Dropbox. It is an online tool programmed to calculate the determinant value of the given matrix input elements. It provides automatic phonemic transcriptions, output customization and edition, export transcriptions to several formats and many other functionalities. Then, as the interest toward matrix converter increased, some manufacturers produced power modules specifically designed for matrix converter applications [9]. 3 Factorization 80 Acknowledgements 83 References 85. Design and Simulation of Matrix Converter for Wind Mill Applications S. In the 1730's Maclaurin wrote Treatise of algebra although it was not published until 1748, two years after his death. The MC is supplied by an ideal 60Hz three-phase source and drives a static resistive load at 60Hz. Read about how we use cookies and how you can control them here. The matrix converter is a forced commutated converter which can perform the power conversion directly from AC power source to the load without any intermediate DC link. It is a highly flexible tool, built upon the foundations of progressive enhancement, that adds all of these advanced features to any HTML table. This yields a highly modular implementation approach which may be suitable for high voltage, high power applications. • World's first matrix converter Drive • Super energy -saving medium-voltage Matrix Converter with Power regeneration • 3kV 200 to 3000kVA • 6kV 400 to 6000kVA • Applications: - Wind/Water Force Machines (blowers, boilers, incinerators), pumps, and general Industrial Machines. Remember - using a larger phase converter than you currently need is safe, but one that is too small will. Basic relationships of voltage and current are given in the table to the right. INTRODUCTION Real development of matrix converters starts with the work of Venturini and Alesina published in 1980. This demo shows how to eliminate dot matrix printers installed on older computer systems. Please consult with planning staff before filing an application. Now over 1,200 organizations in nearly 60 countries rely on Stackify's tools to provide critical application performance and code insights so they can deploy better applications faster. The solution set of such system of linear equations doesn't exist. Create everything from simple web maps to complex analytical models. Click here to determine the size. Code samples. For example, a single layer in a typical network may require the multiplication of a 256 row, 1,152 column matrix by an 1,152 row, 192 column matrix to produce a 256 row, 192 column result. Gephi is open-source and free. Mathematics Applied to Physics and Engineering Applications and Use of the Inverse Functions. The main diagonal of a square matrix are the elements from the upper left to the lower right of the matrix. For quaternions, it is not uncommon to denote the real part first. Matrix Calculators. the U1000 delivers high flexibility and motor control performance to meet a wide variety of application requirements. You can learn much more about working with SmartArt graphics by reading the related information listed at the bottom of this article. 1 Inverter and matrix converter Jun-ichi Itoh Akihiro Odaka Ikuya Sato High Efficiency Power Conversion Using a Matrix Converter 1. They will be deleted again as soon as your conversion is finished. matrix converter technology. the voltage ratio of MC can reach to the 0. Free bulk conversion of PDF documents to plain text files, which can be opened by any text editor. , for a matrix 1 indicates rows, 2 indicates columns, c(1, 2) indicates rows and columns. Eigenvalues and Eigenvectors Projections have D 0 and 1. ABSTRACT SiC-SiC composites offer excellent potential for fusion energy as well as numerous commercial. In this thesis two matrix converter topologies, direct and indirect, are studied. Two potentiometers, connected to analog pins 0 and 1, control the movement of a lit LED in the matrix. How to write an expression like ax^2 + bxy + cy^2 using matrices and vectors. Multirate Digital Filters, Filter Banks, Polyphase Networks, and Applications: A Tutorial Multirate digital filters and filter banks find application in com- munications, speech processing, image compression, antenna sys- tems, analog voice privacy systems, and in the digital audio indus- try. Discover events that match your passions, or create your own with online ticketing tools. S Figure 2. Due to its high speed, it is necessary to use a frequency converter to deliver the power at 50/60Hz. In this work, a dynamic model of matrix converter is studied and issues such as efficiency, voltage ratio limitation, and transient behavior are discussed and the equivalent numerical calculations are presented. The statements and. Applications range from computers, pumps, welders, ovens, to CNC mills, etc. I wanted. Kofax Power PDF solutions are powerful and intuitive tools designed for individual users or for enterprise deployment to create, convert, edit and share PDF files. Amphenol Aerospace is one of the largest manufactures of interconnect products in the world for Military, Commercial Aerospace and Industrial Markets. Matrix converter, SPWM, Utility cost saving, Regeneration power unit selection. Multilevel switching reduces system. Employing the same circuits connected to second switching node. Micro-Vu manufactures non-contact and multisensor measurement machines including Automated Vision Systems, Manual Vision Systems, and Optical Comparators for measuring, quality assurance, and incoming inspection. 2 Products of Toeplitz Matrices 67 5. (Equivalent systems have the same solution. It allows your DOS applications to print to any printer. All conversions among the CSR, CSC, and COO formats are efficient, linear-time operations. The output voltage waveforms are constructed by piecing together selected segments of the input voltage waveforms. The role of the front-end SCSR is to convert the supply ac voltage into an. OCW is open and available to the world and is a permanent MIT activity. Connect the copper port of Cisco switch with RJ45 port of fiber media converter by using an UTP cable. Elementary Row Operations To solve the linear system algebraically, these steps could be used. This is the snippet Convert a Byte Array to a String on FreeVBCode. This can help porting MATLAB applications and code to R. It calculates eigenvalues and eigenvectors in ond obtaint the diagonal form in all that symmetric matrix form. Yaskawa's AC7 Matrix Drive leads a new age of drive performance. Three-phase full wave converter. Abstract: In recent decades, the matrix converter (MC) has emerged as a promising AC/AC converter that performs the direct AC-to-AC conversion. PhoTransEdit. The matrix converter is an alternative to an inverter drive for three-phase frequency control [3]. In particular, the objective has been to define a minimal base ASCII file format which can be very easily explained and parsed, but can easily adapted to applications with a more rigid structure, or extended to related data objects. Definition of Matrix. C# Data Matrix Image Reading. You can build a rotation matrix to rotate about any arbitrary axis like this: Where and (x,y,z) is a unit vector on the axis of rotation. Galea et al. For example, Enter an Octal string: 147 The equivalent decimal number "147" is: 103 RadixN2Dec (String & char) Write a program called RadixN2Dec to convert an input string of any radix (<=16) into its equivalent decimal number. Understanding matrix is important to solve linear equations using matrices. Abstract: In recent decades, the matrix converter (MC) has emerged as a promising AC/AC converter that performs the direct AC-to-AC conversion. The element of matrix A that is in the i-th row and j-th column is denoted as A i,j. x5yz11 3z12 2x4y2z8 +−=− = +−= All of the following operations yield a system which is equivalent to the original. Pressing [MENU]→Matrix & Vector→Determinant to pastes the Det command. •independent of point order. Online Conversion is a resource for weights, measures, calculators, converters. , and Meena, V. – Proven with radiography applications – Just becoming available in fluoroscopy • CsI scintillator systems (indirect conversion) • a-Se systems (direct conversion) Photodetector: a - Si TFT active matrix array Scintillator X-rays to light Photodiode: Light to electronic signal TFT: Storage and readout Amplifiers – Signal out. Transitioning to next generation security platforms should be as seamless as possible. : TECHNOLOGICAL ISSUES AND INDUSTRIAL APPLICATION OF MATRIX CONVERTERS 4261 Fig. Application examples from real life are then provided. Sankara Narayanan, Senior Member, IEEE Abstract—Reverse blocking MOS controlled devices will. Most of the these topologies are based on the structure of the matrix converter. The statements and. (ADI) today introduced the AD9164 D/A converter that brings high resolution radar images for designers of military and commercial radar while reducing solution component count. NET Framework. We manage the largest public pension fund in the US. 1; 1/—its signs are reversed by R. A technique has been presented for reducing the injection of harmonic current into the grid for matrix converter controlled induction generator, for application in wind energy conversion systems. It explains how to prevent connection loss when Plena matrix is connected to a network with multicast traffic. 3-2-3GSDI HDMI 1. This calculator is designed to calculate $2\times 2$, $3\times3$ and $4\times 4$ matrix determinant value. com’s cloud based software runs on both Windows and Mac computers with no downloads or complex installation needed. Each application has unique capabilities to suit your needs. Distributing Python Modules publishing modules for installation by others. It offers planning and optimization functionalities in different business processes of Demand Planning, Supply Planning, Supply and Demand Matching, Production Planning Detailed Scheduling, Global Available to Promise and Transportation Management. MATERIAL SELECTION GUIDE This selector guide is intended to help you review the needs of your particular application and determine a few material candidates that can then be tested. Our rates are trusted and used by major corporations, tax authorities, auditing firms, and individuals around the world. A Rating Scale question, commonly known as a Likert Scale, is a variation of the Matrix question where you can assign weights to each answer choice. Understanding matrix is important to solve linear equations using matrices. We’ll help you scale, even to a global level. Linear Equations and Matrices In this chapter we introduce matrices via the theory of simultaneous linear equations. Excessive heat generating slippage and rpm flair up can make street driving miserable and costly with a converter that is too. It is not intended to give details on the functionality of a buck converter or how to compensate a converter. Find Matrix CREE CANBUS LED Conversion Headlight Bulbs CRE-01-103 and get Free Shipping on Orders Over \$99 at Summit Racing! Light up the night with a set of Matrix CREE LED conversion headlight bulbs. Flame Emission Spectroscopy (FES) In flame emission spectrometry, the sample solution is nebulized (converted into a fine aerosol) and introduced into the flame where it is desolvated, vaporized, and atomized, all in rapid succession. Samples below implement this animation: Matrix as a 64-bit long integer. In this thesis two matrix converter topologies, direct and indirect, are studied. The Modular Multilevel Matrix Converter (M3C) performs a direct three-phase AC to AC power conversion and is highly suitable for medium voltage high power drive applications. Let’s consider a vector v whose initial point is the origin in an xy - coordinate system and whose terminal point is. Yaskawaʻs development of the worldʼs first application of matrix converter technology in 2006 made it possible to solve AC drive problems. The converter without dc link will be preferred over the two stage ac-dc-ac conversion in the existing power conversion arrangements in the ac traction drives. Kolar from the ETH Zurich. This paper shows that it is possible to use the six-phase matrix converter to increase the maximum voltage gain. and you can convert between less obviously related structures, such as from a matrix to a set. This sophisticated series of motor drives available only from Yaskawa eliminates the problems of standard AC drives. A New Matrix Based Non-isolated Three Phase Buck-Boost Rectifier. the single phase matrix converter switching arrangement. Matrix Converter: Currently the application of matrix converters are limited due to non-availability of bilateral monolithic switches capable of operating at high frequency, complex control law implementation, commutation and other reasons. De Souza, and E. It uses the power of 4Matrix to provide top-level analysis of school performance data to support the reporting of Performance Indicators for MATs. Flexmls-connected home search for any website. Connect the copper port of Cisco switch with RJ45 port of fiber media converter by using an UTP cable. Foreign exchange rates of major world currencies. Works in HP 48 G/G+/GX, as far as I know. The matrix converters (MC) is a direct ac-to-ac converter, replaces the multiple conversion stages and the intermediate energy storage elements (dc-link) thus. Its front-end is a conventional CSR and its rear-end is an ASN composed of two IGBTs and two diodes. Most attention was concentrated on tree phase matrix converter topology. Khronos has formed a liaison agreement with the Open Geospatial Consortium (OGC) in the interest of jointly advancing open geospatial standards related to AR and VR, distributed simulation, and 3D content services. This would not of course be an issue for a custom solution such as an integrated motor drive, where the motor winding voltage could be selected. is a global technology leader that designs, develops and supplies semiconductor and infrastructure software solutions. D/A Converter Offers More Accuracy in a Smaller Footprint for Diverse Applications Ranging from Radar to Smartphone Testing Aug 8 2016 - Norwood, MA Analog Devices, Inc. Optionally, set up user, role, and role assignment synchronization. OANDA's currency calculator tools use OANDA Rates ™, the touchstone foreign exchange rates compiled from leading market data contributors. , for a matrix 1 indicates rows, 2 indicates columns, c(1, 2) indicates rows and columns. and you can convert between less obviously related structures, such as from a matrix to a set. All saturation matrices can be derived by interpolating between or. Proceedings of the 2011 - Grand Challenges in Modeling and Simulation Conference, GCMS 2011. This MATLAB function converts sparse matrix S to full storage organization, such that issparse(A) returns logical 0 (false). Application examples from real life are then provided. This Application Note describes how to examine the network and look for the multicast sources on the network. The thermal performance of the LLC converter operating at 54 V input, 900 W load, and with an air flow of 400 LFM, is shown in figure 6. About this World Clock / Converter. Learn the C++ language from its basics up to its most advanced features. Also it calculates the inverse, transpose, eigenvalues, LU decomposition of square matrices. With Metrics Conversion, you get a quick conversion right from your Android device. 9, SEPTEMBER 2005 2075 MOS Control Device Concepts for AC-AC Matrix Converter Applications: The HCD Concept for High-Efficiency Anode-Gated Devices Ngwendson Luther-King, Mark Sweet, Oana Spulber, Konstantin V. The Linear System Solver is a Linear Systems calculator of linear equations and a matrix calcularor for square matrices. This metric can be used to track maintenance hours per function point. Read "Application of the matrix converter to power flow control, Archives of Electrical Engineering" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. The goal of this project was to develop a new modular multilevel matrix converter for wind power applications and to demonstrate a working scale model in the laboratory. Easily share your publications and get them in front of Issuu's. Scalar Product of Vectors. quadratic forms which led naturally towards matrix theory. In many applications, such as flat panel TVs, 85+ ATX PCs or small form factor PCs, where the. Free online image converter to convert your images and photos on the go. APO (Advanced Planning and Optimization) application is at the heart of SCM. The debate over the method's theoretical-philosophical underpinnings, on the other hand, has never quite stopped festering (e. Since 2003, Vertex42® has been creating professionally designed spreadsheet templates for business, personal, home, and educational use. Also, it is often the case that the outputs do not directly depend on the inputs (only through the state variables), in which case is the zero matrix. Do you want to learn MATLAB ®?. 2008-07-22: Moved site to a new server. Generate Plain Old Java Objects, XML from JSON or even JSON-Schema. List comprehensions provide a concise way to create lists. In addition, we will for-mulate some of the basic results dealing with the existence and uniqueness of. Some drawing applications such as Adobe Illustrator and Corel Draw have this option built in. European Union Aviation Safety Agency. The confusion matrix itself is relatively simple to understand, but the related terminology can be confusing. Sankara Narayanan, Senior Member, IEEE Abstract—Reverse blocking MOS controlled devices will. For queries/help regarding SBI Credit Cards, you can contact us via any of the available options such as Call, Fax, E-mail, Twitter, SMS, etc. the single phase matrix converter switching arrangement. This is calculated by dividing the total number of visitors (to a site, page, category, or selection of pages) by the total number of conversions. Capturing renewable energy, every day. Understanding matrix is important to solve linear equations using matrices. Keywords: Matrix Converter (MC), cross coupled DQ axis controller, fuzzy controller, Power Quality. Operations on vectors - addition, multiplication by a number. Intends to Separate Applications 42 24. Creating the Form. ParaView is an open-source, multi-platform data analysis and visualization application built on top of VTK. Look up your current conversion rate. The elimination of the intermediate DC link capacitor needed for the common converters used today, makes it an "all silicon" device to be used for motor drives. In MacOS X this is usually the "Applications" directory, but you are free to put it anywhere you want. Learn More About the Software. A matrix-forming fluid is contained within a chamber defined by top and bottom surfaces of a thermally conductive material and spacers defining the thickness of the matrix. The application file should work properly on MacOS X 10. Our rates are trusted and used by major corporations, tax authorities, auditing firms, and individuals around the world. Invalid cast if the destination matrix has more components than the source matrix. the U1000 delivers high flexibility and motor control performance to meet a wide variety of application requirements. Weeks' Method "Application of Weeks method for the numerical inversion of the Laplace transform to the matrix exponential", P. You can convert from over 120 source formats. Consider a triangle with vertices at (x 1,y 1), (x 2,y 2), and (x 3,y 3). I have found it hard to use it mainly due to lack of documentation, which is really basic with only few code examples for C#. Python HOWTOs in-depth documents on specific topics. It is not intended to give details on the functionality of a boost converter (see Reference 1) or how to compensate a converter. We help businesses of all sizes operate more efficiently and delight customers by delivering defect-free products and services. Although OpenGL allows you to decide on these steps yourself, all 3D graphics applications use a variation of the process described here. An 8x8 LED matrix contains 64 LEDs which are arranged in the form of a matrix, hence the name LED matrix. APO (Advanced Planning and Optimization) application is at the heart of SCM. The matrix converter is a forced commutated converter which can perform the power conversion directly from AC power source to the load without any intermediate DC link. World Wide Metric serves the needs of the global maritime and industrial flow control and fluid power markets. Extending and Embedding tutorial for C/C++ programmers. New to Oracle Community? Be sure to check out our FAQ and read through the Community Guidelines. 6 % of the. Nokia TAS has fully featured application development capabilities. The statements and. List comprehensions provide a concise way to create lists. Modeling of Matrix Converter using OAVM modulation strategy. ffmpeg already had basic support for these subtitles which ignored all formatting information - it just provided basic plain-text support. Now you can compare various types of paper and their "Equivalent Weights. switching convertors matrix convertors power semiconductor switches printed circuits PCB intelligent bidirectional power switch module matrix converter application power transistors gate driver galvanic isolation over-voltage protection device floating voltage power supplies control circuitry bidirectional switch Matrix converter IPM. 877, the requirement of a large number of switches and the complex control of these switches. A high frequency high power transformer is suggested to electrically isolate the generator and to raise the voltage. In-Rate Willing to Convert Applications 38 21. 0106 For access to this article, please select a purchase option:. A matrix is a rectangular array of numbers, arranged in rows and columns. Comparison Matrix Which CorelDRAW® product is right for you? CorelDRAW Graphics Suite X6 is a complete suite of professional graphic design software, including superior vector illustration and page layout applications, advanced photo-editing capabilities and more. A GPA is actually your grade point average of all your course grades divided by the total number of credits. Transitioning to next generation security platforms should be as seamless as possible. Excessive heat generating slippage and rpm flair up can make street driving miserable and costly with a converter that is too. hello, i am working with similar application in asp. Generate Plain Old Java Objects, XML from JSON or even JSON-Schema. An indirect matrix converter is also a direct frequency converter having the same features of an MC, but now a DC stage is clearly identified in the topology. See why Gartner has named Oracle a leader for Cloud Financial Planning and Analysis Solutions and for Cloud Financial Close Solutions. 1 Inverses of Toeplitz Matrices 62 5. Further evolution of this technology has resulted in the U1000L. pulsed currents on the input side of the matrix converter. Matrix Logic Corporation is a national integrator of Enterprise Content Management (ECM). (ADI) today introduced the AD9164 D/A converter that brings high resolution radar images for designers of military and commercial radar while reducing solution component count. © Muri, 2006. This paper will present a review of present industrial appli-. Buy Applications Converters Matrix Converters from eBay and save. Then, join our Getting Started group, introduce yourself, and start exploring! Want to offer feedback, or share your ideas? We'd love to hear from you!. In the 1730's Maclaurin wrote Treatise of algebra although it was not published until 1748, two years after his death. include selectors for configuring the mode conversion, which includes the configuration of input and output port assignments, and the Apply button to invoke the conversion. Besides the classical outer control loops also presented by older VSC-HVDC applications in which the two level converter type is adopted, the control of multilevel converters in principle relies on the com-bination of current, balancing and cell voltage controllers [8, 9, 10]. In some cases, you might actually want to use quaternions in GLSL, for instance if you do skeletal animation on the GPU. Manage SharePoint sites, content and metadata on an ongoing basis to keep in sync with business needs. NSF's mission is to advance the progress of science, a mission accomplished by funding proposals for research and education made by scientists, engineers, and educators from across the country.


text:
The »bohr« package

Sometimes things go fast. This weekend a question on TeX.sx popped about how to create Bohr models with LaTeX. Soon some very nice answers were given but I had a feeling that a more generic approach would be nice. I decided to answer the question myself. Since the code got a little longer I put it into a package for convenience but soon after thought it might also be useful for others. So, here it is.

\documentclass{article}
\usepackage{bohr}
\begin{document}

\bohr{11}{Na}
\bohr{28}{Ni}

\setbohr{name-options-set={font=\footnotesize\sffamily}}
\bohr{18}{Ar}
\bohr{2}{He}
\bohr{7}{F
}% damn, that should have been N...

\bohr[3]{10}{$\mathrm{Na^+}$}

\end{document
}

format: plain


text:
Tag Info

New answers tagged aerodynamics

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Because where they come close together the air in between circulates in such a way as to join them in a single path. Floris is right, but maybe this picture helps.

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Intuitive start of an answer: If you have counter rotating vortices they have zero net angular momentum (to first order). If they merged they would have to have no motion -> where did the energy go. In between the two axes of rotation the fluid moves in the same direction and has no mechanism for dissipation. By contrast for two vortices with the same ...

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Mark's answer is fantastic and steps through much of the physical reasoning involved wonderfully. But annoyingly, in this particular case the region of interest is pretty much right where both air resistance starts to become nontrivial and important and the details of the velocity of the ball off of the club also has non trivial behavior, so I decided to ...

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My guess is, this is related to low pressure on your mouth (and much less noticeably - high pressure on your chest) which makes it harder for you to inhale. -When you lower your head, you prevent your mouth from being drained of air by making it into sort of a bubble free from the airflow. This could be related to a RollerCoaster - Have you ever tried not ...

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I think you are misunderstanding the article. I also think that the name 'Flying Saucer' is a bit misleading. I think referring to it with the actual project name: 'Low Density Supersonic Decelerator' (LDSD) fits better. The concept of this project is that a spacecraft uses a inflatable saucer-shaped balloon to increase its reference area (the surface area ...

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This is an optimal control problem, so I will use the rules of optimal control. First, we represent the state space equations. Also we take the total mass as a state and amount of fuel burnt as the input control. So we have: \begin{cases} \tag{1} \dot{x}_1=x_2 \\ \dot{x}_2=\frac{\eta \theta-k(x_1)x_2^2}{x_3}-g \\ \dot{x}_3=-\theta \end{cases} with these ...

0

I thought this question was interesting and I didn't want to do any proper work this afternoon so I made a simple model to find out what would happen. My matlab code is at the end of the question. So far I've tested three cases and considered changing the initial thrust and adding a linear increase in the thrust for each case. The thrust is given as a ...

0

The spinning of the wheel is a cconsecuence of the assymetry in the air stream it receives. This rotation obviously reduces the drag experienced by the car. To explain it let us consider, instead the bicycle wheel, a wheel with blades like a windmill. It is obvious that the car travels more quickly when this wheel is free to rotate.

2

This phenomenon is probably related to the cold shock response, a set of physiological changes that come about in response to rapid temperature change, such as that experienced by a human whose face is immersed in a cold fluid. The response is accompanied by respiratory changes, including an initial gasp (see here). It is related to the dive reflex. This ...

0

Consider helicopters, which are simply aircraft whose wings go in a circle. Then consider those flying platforms consisting of a fan pointed down. The only real difference is whether the wings are big and slow versus small and fast. Lift consists of the momentum (per second) of air directed downward. Momentum is $mv$. That air has kinetic energy ...

0

The lift of a wing is proportional to the square of the air velocity passing over it. If you have a wing it is thus very easy to get a lot of lift just by increasing your speed. In this way, rather than using engine force to lift the aircraft directly, you use the engine force to push you in the direction you want to go as fast as possible. This means you ...

17

Let's look at the relationship between momentum and energy. As you know, for a mass $m$ kinetic energy is $\frac12mv^2$ and momentum is $mv$ - in other words energy is $\frac{p^2}{2m}$ Now to counter the force of gravity we need to transfer momentum to the air: $F\Delta t = \Delta(mv)$ The same momentum can be achieved with a large mass, low velocity as ...

2

I've wondered about this a bit before. I think it's good to hugely simplify things to think about it. Incidentally, I'm absolutely not a source of authority here. I'm just thinking it through from what seems apparent to me. A falling plate You've said specifically that you don't want to think about how wings work, so let's not. Forget about the wing. ...

0

There are planes that tilt the engine down to take off those are called VTOL (vertical Take Off and Landing). These are usually military fighter craft. The reason why they aren't used for general aviation is multifold: First every regulation aircraft must be able to touch down safely after losing an engine, if the engine is what provides the lift then the ...

0

You can also consider how a glider can achieve much greater distances than a rocket, whilst expending no energy at all! Ah, no. One expends energy in the launch phase - an aerotow or winch launch being typical - and gains energy in slope, wave, dynamic or thermal lift and then expends it in overcoming drag. Energy management is one of the most ...

4

Why is an airplane better than a rocket? Because the plane grips the medium. For a rocket to remain at a fixed altitude, it must continually thrust upwards in order to counteract the fall caused by gravity. It does this by pushing down a large amount of air and fuel each second. An airplane can create this same upward force to counteract gravity, but in ...

0

How about this explanation (not that detailed, but simple): The reason is that, if force of lift and force of gravity cancels each other out exactly, then staying airborne requires zero energy. Basically, energy and force are different things. A helium balloon can stay in the air indefinitely, without needing energy to do so, and without the air supplying ...

0

It seems that the width of the blade is missing. If we compare it with the 'traditional formula' for drag generated by an airfoil (assumed with $\sin \phi=1$), we have: $$F=C_D \cdot 0.5 \rho V^2 S$$ see Wikipedia Drag Coefficient. Where $C_D$ denotes the airfoils capacity to generate drag. This value does not show up in the formala given for the place, ...

6

The key point is that wings allow you to "tilt the engine" much more efficiently than actually tilting it. Tilting an engine converts the power only at 1-to-1 ratio, but wings do it better - a Boeing 747 has a lift/drag ratio of 17 at cruise speed, the wing is generating 17 times more lift than the applied engine power.

2

I think You have Your intuitions a bit scrambled. Engine and wings do not have the same function. If You need to make a parallel then wings have the same function of wheels on a car: they provide an efficent way to remain above ground by pushing down on some medium. Wheels push on ground and have no problem keeping your car above it even when the car is ...

4

The important quantity in determining the effectiveness of a wing is its lift to drag ratio. It turns out that the key contributer to a large lift to drag ratio is a large wing span ($b$ in the below equation). As such the large wings on the aircraft can be far more efficient at generating maximum lift with minimal drag that the smaller "wings" of the ...

1

Wings have a much larger surface area than engines, so they are better at preventing a plane's gravitational potential energy from being converted into downward kinetic energy. A plane with gliders instead of wings and engines pointed downward at an angle should be just as energy efficient as a regular plane. The glider might be less practical because the ...

5

It is merely a long comment but hopefully it gets your intuition on the right track. I try to detail the physical part of the reason why having fixed wings is a good thing: You basically ask, why are airplanes more efficient (hence people still produce them despite their less nice maneuverability) well you probably noticed helicopter rotors work pretty ...

0

Use an incense stick to test. You will find that the only turbulence is from the heated air (smoke) rising from the stick, or from moving the stick around. If you can cool the smoke to room temperature without heating the area of interest, you are likely to get layers unless the room or outdoor area has no temperature gradient with height. Where is gets ...

1

Theoretically, the radial distribution should be symmetric. However, in jets in general it is well know that there will be a transition from purely laminar (i.e. symmetry preserving) to purely turbulent (breaks the symmetry). Have a look at this video. The presence of the plasma induces the turbulence at much earlier in space compared to when it is absent. ...

Top 50 recent answers are included


text:
# ICRC2015

July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

## LARGE-SCALE ANISOTROPY OF TeV-BAND COSMIC RAYS

Jul 30, 2015, 3:30 PM
1h
Amazon Foyer (World Forum)

### Amazon Foyer

#### World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 185
Poster contribution CR-TH

### Speaker

Rahul Kumar (Ben Gurion University)

### Description

The expected anisotropy in the 1 to 104 TeV energy range is calculated for Galactic cosmic rays with both anisotropy in the diffusion tensor and source discreteness taken into account.We find that if the sources are distributed radially (but with azimuthal symmetry) in proportion to Galactic pulsars, the expected anisotropy almost always exceeds the observational limits by one order of magnitude in the case of isotropic diffusion. If the radial diffusion is more than an order of magnitude smaller than the azimuthal diffusion rate, the radial gradient of the sources can be accommodated about 5% of the time. If the sources are concentrated in the spiral arms, then the anisotropy depends on our location between them, but in some spatial window, roughly equidistant from adjacent spiral arms, the observational constraints on anisotropy are obeyed roughly 20%–30% of the time for extremely anisotropic diffusion. The solar system is in that window less than 10% of the time, but it may be there now. Under the assumption of isotropic diffusion, nearby supernovae are found to produce a discreteness anisotropy that is nearly two orders of magnitude in excess of the observational limit if all supernovae are assumed to contribute equally with a source rate 1 in every 100 years
Registration number following "ICRC2015-I/" 168 -- not specified --

### Primary author

Rahul Kumar (Ben Gurion University)

### Presentation materials

There are no materials yet.


text:
# Maximal tori: Overview

## Maximal tori: overview

We now want to understand groups more general than $SU(2)$ and $SU(3)$ . One of the key ingredients we used to study those special groups was the weight diagram, which encoded the information about how a representation decomposes under the action of a the diagonal subgroup: $T=\left\{\begin{pmatrix}e^{i\theta}&0\\ 0&e^{-i\theta}\end{pmatrix}\ :\ e^{i\theta}\in U(1)\right\}\cong U(1)$ inside $SU(2)$ and $T=\left\{\begin{pmatrix}e^{i\theta_{1}}&0&0\\ 0&e^{i\theta_{2}}&0\\ 0&0&e^{-i(\theta_{1}+\theta_{2})}\end{pmatrix}\ :\ (e^{i\theta_{1}},e^{i\theta% _{2}})\in U(1)^{2}\right\}\cong U(1)^{2}$ inside $SU(3)$ .

Definition:

A torus in a matrix group $G$ is the image of a smooth injective homomorphism $U(1)^{n}\to G$ for some $n$ .

Remark:

It's called a torus by analogy: $U(1)\times U(1)$ is topologically a 2-dimensional torus (doughnut shape) as a torus has two angular coordinates like $U(1)\times U(1)$ . Higher dimensional tori are defined to be products of more copies of $U(1)$ .

Definition:

A torus is called maximal if it is not contained in a strictly bigger torus.

Remark:

We're focusing on maximal tori because these will give us the most refined decomposition into weight spaces: if you pick a submaximal torus you will always be able to decompose your weight spaces further using the action of the additional $U(1)$ -factors of a bigger, maximal torus. For example, if we'd just used $\theta_{1}$ in $SU(3)$ , we wouldn't have seen the nice 2-dimensional weight diagrams that gave us so much information: we would only have seen projections of these diagrams down to a 1-dimensional line.

## Examples of maximal tori

Example:

For $SU(n)$ , the diagonal subgroup $T=\left\{\begin{pmatrix}e^{i\theta_{1}}&&{\large 0}\\ &\ddots&\\ {\large 0}&&e^{i\theta_{n}}\end{pmatrix}\ :\ \theta_{1}+\cdots+\theta_{n}=0\right\}$ is a maximal torus. This specialises to our earlier examples for $n=2$ and $3$ .

Example:

The subgroup $T=\left\{\begin{pmatrix}\cos\theta&-\sin\theta&0\\ \sin\theta&\cos\theta&0\\ 0&0&1\end{pmatrix}\ :\ \theta\in\mathbf{R}\right\}$ of rotations around the $z$ -axis is a maximal torus in $SO(3)$ .

In $SO(4)$ , we can find the 2-dimensional maximal torus: $T=\left\{\begin{pmatrix}\cos\theta_{1}&-\sin\theta_{1}&0&0\\ \sin\theta_{1}&\cos\theta&0&0\\ 0&0&\cos\theta_{2}&-\sin\theta_{2}\\ 0&0&\sin\theta_{2}&\cos\theta_{2}\end{pmatrix}\ :\ \theta_{1},\theta_{2}\in% \mathbf{R}\right\}$

In $SO(5)$ we can still only find a 2-dimensional maximal torus: $T=\left\{\begin{pmatrix}\cos\theta_{1}&-\sin\theta_{1}&0&0&0\\ \sin\theta_{1}&\cos\theta&0&0&0\\ 0&0&\cos\theta_{2}&-\sin\theta_{2}&0\\ 0&0&\sin\theta_{2}&\cos\theta_{2}&0\\ 0&0&0&0&1\end{pmatrix}\ :\ \theta_{1},\theta_{2}\in\mathbf{R}\right\}$ There's no room for another diagonal 2-by-2 block.

Remark:

This is one of the first points where we see a significant difference between odd-dimensional rotation groups and even-dimensional rotation groups: relative to the dimension of the group, there's a lot more off-diagonal stuff in odd-dimensional rotation groups.

## Theorem

Theorem:

Let $G$ be a compact, path-connected matrix group (bounded matrix entries). Then:

1. $G$ contains a nontrivial torus if $G$ is nontrivial.

2. Any element of $G$ is contained in a torus.

3. Any torus is contained in a maximal torus.

4. Any two maximal torus $T_{1}$ and $T_{2}$ are conjugate, i.e. there exists an element of $g$ such that $T_{2}=gT_{1}g^{-1}$ .

We will not prove (4): the proof would take us too far away from the main themes of the course. The proof uses some very cool ideas from topology, including the Lefschetz fixed point theorem. You can do an in-depth project on this, but it does require a bit of background in topology. We will also not prove (2) fully, though we will make a remark about what we would need for this.

Before we move on to the proof, here are some examples to see why the hypotheses of the theorem are necessary.

Example:

Suppose $G$ is the real numbers with addition. Since the real line doesn't contain a topologically embedded circle, there's no way to get a nontrivial torus in $G$ . The real line is path-connected, but not compact, so we see that compactness is necessary.

Example:

The assumption of path-connectedness is necessary for part (2) of the theorem. For example, consider $G=O(2)$ , the group of orthogonal 2-by-2 matrices. This has two components: the rotations and the reflections. Each component is topologically a circle. The identity component (the subgroup of rotations) is a torus; this the only torus (since any torus is connected and contains the identity) and none of the reflections is contained in it, so the claim that every element of $G$ is contained in a torus fails.

## Pre-class exercise

Exercise:

Can you see why the tori we have been using in $SU(2)$ and $SU(3)$ are maximal?


text:
# Some epsilon-delta proofs

From Salas’s Calculus, 10th edition, page 104: Chapter 2 review exercise 45. Below, the important thing to keep in mind is that we want to use the “piecewise function idea”: that if a function can be thought of as a piecewise function, we first want to restrict it to where it is essentially nonpiecewise, and then show that the limit exists there.

Proof. We want to show . If , then so so , which means is negative. But then . So we want to show that for all satisfying , that holds. But using what we know, is the same thing as as long as . So let . Then so But since , we know So i.e. . From we have then


text:
# To show that a function is not of bounded variation on [0,1]

What would be a sequence of partitions of [0,1] to show that the function

$f(x)$ = \begin{cases} 0, & \text{if $x$ $\in$[0,1]$\cap$$Q^c} \\ -x, & \text{if x$$\in$[0,1]$\cap$$Q$} \end{cases}

is not of bounded variation on [0,1]?

• Alternate between rational and irrational points. – Daniel Fischer Nov 26 '16 at 20:47
• It is a variation at least $1/2$ between rational and irrational points for $x\ge 1/2$, and there are infintely many such changes in this part of the interval. – A.Γ. Nov 26 '16 at 20:49
• @DanielFischer thank you. It works. – Janitha357 Nov 26 '16 at 21:19

$x_n = \frac{1}{n}$ , if $n$ is odd
$=\frac{1}{n+n^\frac{1}{n}}$ , if n is even.
• The site supports latex, write $5\cdot5$ and you get $5\cdot 5$. – peterh May 28 '18 at 13:49


text:
# zbMATH — the first resource for mathematics

Counting Carmichael numbers with small seeds. (English) Zbl 1225.11161
Let $$A_s$$ be the product of the first $$s$$ primes (called seeds by the author), $${\mathcal P}_s$$ the set of primes $$p$$ for which $$p-1$$ divides $$A_s$$ but $$p$$ does not divide $$A_s$$, $${\mathcal C}_s$$ the set of Carmichael numbers $$n$$ such that $$n$$ is composed entirely of the primes in $${\mathcal P}_s$$ and such that $$A_s$$ divides $$n-1$$. The author gives numerical evidence for the conjecture: $|{\mathcal C}_s|=2^{2^{s(1-\varepsilon)}}, \lim_{s\to\infty}\varepsilon=0.$ This shows that $$|{\mathcal C}_s|$$ grows rapidly with $$s$$. He describes a procedure to compute exact values of $$|{\mathcal C}_s|$$ for small $$s$$.

##### MSC:
 11Y11 Primality 11Y16 Number-theoretic algorithms; complexity 11Y35 Analytic computations
##### Keywords:
Carmichael numbers
Full Text:
##### References:
 [1] W. R. Alford, Andrew Granville, and Carl Pomerance, There are infinitely many Carmichael numbers, Ann. of Math. (2) 139 (1994), no. 3, 703 – 722. · Zbl 0816.11005 [2] R. D. Carmichael, Note on a new number theory function, Bull. Amer. Math. Soc. 16 (1910), no. 5, 232 – 238. · JFM 41.0226.04 [3] Richard Crandall and Carl Pomerance, Prime numbers, 2nd ed., Springer, New York, 2005. A computational perspective. · Zbl 1088.11001 [4] P. Erdös, On pseudoprimes and Carmichael numbers, Publ. Math. Debrecen 4 (1956), 201 – 206. · Zbl 0074.27105 [5] A. Granville, Primality testing and Carmichael numbers, Notices of the American Mathematical Society 39 (1992), 696-700. [6] A. Korselt, Problème chinois, L’intermédiaire des mathématiciens 6 (1899), 142-143. [7] Richard G. E. Pinch, The Carmichael numbers up to $$10^{21}$$, in Proceedings of Conference on Algorithmic Number Theory 2007 (edited by Anne-Maria Ernvall-Hytönen, Matti Jutila, Juhani Karhumäki and Arto Lepistö), Turku Centre for Computer Science General Publication 46 (2007), 129-131. http://tucs.fi/publications/insight.php?id=pErJuKaLe07a&table=proceeding
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.


text:
# Find index of an object with a specific value stored in an array

I am using the following code in order to retrieve the index for an object stored in a JavaScript array.

Scripts works fine, but I would like your opinion regarding performance.

Also would like to know also if using [].map() could be more appropriate of [].some().

http://jsbin.com/nasiyiyavi/1/

var data = [{ id: 3 }, { id: 4 }, { id: 1 }, { id: 0 }, { id: 2 }];

function findIndexInData(optionsArg) {
var options = {
data: optionsArg.data,
where: optionsArg.where,
what: optionsArg.what
},
result = -1;
options.data.some(function (item, i) {
if (item[options.where] === options.what) {
result = i;
return true;
}
});
return result;
}
alert(findIndexInData({ data: data, where: 'id', what: 2 }));

Eric Blade is correct that this is a perfect use-case for findIndex. But I'd like to comment on your current code:

• Why are you using an object to pass the arguments? You need all three components (data, where, and what), whereas a object usually means each part is optional. If you want to make it clear that all the parts are required, then just use regular arguments:

function findIndexInData(data, property, value)

I'm also naming them property and value, since that's the usual name for such things (or key and value).

• I'm not sure what the purpose of this part is:

var options = {
data: optionsArg.data,
where: optionsArg.where,
what: optionsArg.what
}

So you start with the optionsArg object, and from that you create... basically an identical object. Why? What's the point?

• I'd probably just use a plain old for loop rather than some

• And if you do that, you don't need the result variable. Right now, you're modifying the closed-over result variable, which, while ok, isn't too pretty.

I end up with this, which seems simpler.

function findIndexInData(data, property, value) {
for(var i = 0, l = data.length ; i < l ; i++) {
if(data[i][property] === value) {
return i;
}
}
return -1;
}

But again, the simplest is probably to just use findIndex, as Eric Blade suggests.

I think the best way of doing that would be using the new ES6 function Array.prototype.findIndex:

data.findIndex(function(obj) { return obj[where] === what; })

If you don't have that function, there are good polyfills at MDN and NPM.

(if you do have full ES6, you apparently could also do

data.findIndex(obj => obj[where] === what)

but i'm still learning how that syntax works so i may be wrong there)

• does the whole "needing polyfill" thing apply to node? Jan 6 '19 at 12:45
• Array.prototype.findIndex was implemented back in node 0.12.x, so you probably don't need a polyfill to anyone using it now Jan 17 '19 at 0:37


text:
## Main Question or Discussion Point

Hello!

This is my first post on this forum, so make sure to tell me if I am doing something wrong :)

I was trying to derive the Lorentz factor today, and I used the following page as a guide. The top answer by Jimmy360 is what I followed.
https://physics.stackexchange.com/questions/173268/deriving-the-lorentz-factor-gamma

I was unable to solve for t' as they did, and it occurred to me that there was perhaps an issue with the derivation. Now I am in no way knowledgeable nor talented in derivations so I wanted to have someone look at my thought process. I have a hard time imagining that the derivation I linked is wrong, but then again I made it work for me with a small change that seems to make sense.

I realize that I am most likely wrong but I can't figure out why. That's why I need your help. If I'm misunderstanding something I want to find what that something is.

So, it seems that Jimmy360 set t' to be the coordinate time, and t to be the proper time.
Hence l=ct (that's an observation made by an observer in the reference frame of the rods), and d=ct' (that's an observation made by an observer in the other reference frame, which doesn't follow the rods)

Now when they find that d2= l2+(vt)2, I would have expected to see d2= l2+(vt')2 instead. The distance that the rods travel in the x-axis is not measured at all by an observer in the rods' reference frame, is it? That's why I expected d to be expressed in terms of f' rather than f

After that change is made we get
c2t'2=c2t2+v2t'2

and then
c2t2=c2t'2-v2t'2

From there I am able to solve for t and in doing so find the Lorentz factor.

Is my thought process correct? If not, can you guide me towards what I don't understand?

Thank you very much for your time, I appreciate it :)

Related Special and General Relativity News on Phys.org
Ibix
There is a mistake in the derivation, yes. It should say $l=ct'$ (i.e. in the frame where the light clock is at rest, it takes time $t'$ for the light pulse to travel one way up the clock) and $d=ct$ (i.e. in the frame where the light clock is moving it takes time $t$ to go up the diagonal distance $d$) not the other way around. The expression as (incorrectly) derived makes $t'/t=\gamma$, but the LHS should be the other way up: $t/t'=\gamma$. If you put the definitions of l and d in correctly the correct answer drops out.

An observation I've made about relativity is that it seems to be quite easy to get correct-looking (but wrong) expressions when you make a mistake.

Last edited:
yes, I agree that it makes sense to have t' in the frame where the clock is at rest, and t in the frame where the clock is moving.

However the choice of variables is not the core mistake, is it? I agree that the proper time should be t' , and the coordinate time t, but realistically what stops us from doing the entire derivation with the variables the other way around? we would simply get the end result
t/t'=γ

What I'm getting at is that in Jimmy's derivation, vt should instead be vt'. It seems to me that that's the core mistake, it's an actual physics mistake.

If we let t' be the proper time as you suggested (which I totally agree is the way to go), then we would have vt instead of vt'

Is that correct?

Thank you once again, I know that I'm being picky but I want to make sure that I understand it all

Ibix
I think that's just another way of saying the same thing.

It's not clear to me whether the original derivation intended to use $t$ for the moving frame or the rest frame. The problem is that it used one in the expression $d=ct'$ and the other in $vt$, which is inconsistent. Both of these should use the same one of $t$ or $t'$, and the expression for $l$ should use the other.

You seem to have fixed the problem by changing $vt$ to $vt'$. I fixed it by switching $t$ and $t'$ in the other two expressions. Either approach is self consistent. Since the original derivation doesn't specify which frame is supposed to be using $t$ and which $t'$, either approach is also consistent with the full problem specification (such as it is).

I'm not sure whether it's a physics problem or a "confused by their own notation" problem. Either way, the maths is inconsistent and you seem to have found a valid fix.

Last edited:
Ok, I get it now. Indeed I was really saying the same thing as you were, just differently.

Thank you, have a great day.


text:
# It is possible to use a 100W 12V solar panel directly to charge a laptop, using a buck converter for example?

I am planning to go off the grid due to the pandemia, to an isolated village. I am working remotely I am looking for a solar approach to power my laptop ACER A5 515. The charger is rated 40W.

I was considering using a 100 Watt panel, an inverter and the power charger. However I was wondering if its possible only adapt those 12 volts to 19 to use with my laptop. And which could be the best way to avoid damaging the electronics.

I think it should be a waste of power using an 100 watt panel from the solar controller, then a 120 v inverter to connect the laptop charger.

I could use the laptop battery to store any excess energy (I only the laptop to be on by 9 hours at day)

Also I will need to have my phone connected as I will using the data tethering and a rechargeable usb light to use at night.

Thanks in advance for any ideas or suggestions.I am looking for an starting point to start constructing this setup

• That won’t be easy. Is there any options for car charging or similar? May 24 '20 at 20:50
• It’s much easier with 19 to 24Vdc with a low ESR cap big enough to drive the laptop motherboard with less current. May 24 '20 at 20:55
• @winny my thought exactly. Why bother with any other solution as there are 12V input car chargers for the laptop available. May 24 '20 at 21:10
• to an isolated village ... that sounds like a totally irresponsible action on your part .... isolated villages usually do not have the medical facilities to handle the influx of covid cases when the virus has been brought in by people like you ... it endangers you and everyone else in the village May 24 '20 at 21:14
• I'd consider a 12V lead acid battery (second hand car battery? leisure battery if you can afford it) and a cheap solar charge controller to protect it. Then 12V to 19V adapters are easily available. All simple cheap (except the leisure battery) and works well together. May 24 '20 at 21:17

It might be possible, but not very reliable.

The reason is the input impedance is very non-linear to any DC-DC converter such as those used on Mobiles and laptops. This means the inability to match impedances from source to load (maximum power transfer theorem) which is the condition for MTTP. Worse yet, the surge start current might shunt the PV into a low power low voltage start condition that fails to draw sufficient current to reach an equilibrium , assuming sufficient power exists for a matched linear load.

PV’s are current sources with Vmpt ~ 82% of Voc with voltage limits.

This means the load instead of appearing as a positive resistance can start as a negative incremental impedance and result in unstable cycle of little or no charging. Boost DC-DC converters work with voltage source inputs it will then have a CC, CV cutoff profile. with low ESR and not with current sources.

Your best bet to make a linear load using the DCR of a battery pack using an array with 24Voc (open circuit and charging a 19V. A good charger with MTTP will match the charger impedance to the battery chemistry and you have a backup to To charge your laptop while charging the other .

Check around for battery specs or purchase a 19 to 20V roughly batt Pack to charge your laptop and emulate the 19.5V universal charger. Then find a PV charger that works on that.

If you plan to go off grid, get some 1kg jars of Vit C with C&L Lycene and Mg. 5,000 IU’s/ day and more if ill. There ought to be enough sun for Vit D. (10,000 IU tab/day )

A battery load is linear and works but a DCDC converter does not unless there is a huge capacitor in between. Your test mileage may. Vary.


text:
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# Low Undergrad GPA Success Stories

Author Message
TAGS:
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Posts: 368
Schools: Ross (R2), Cornell (R3) , UNC (R3) , INSEAD (R1 Jan)
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Kudos [?]: 92 [5] , given: 45

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Being that there are a lot of threads addressing how to overcome a low GPA, here is a thread for success stories only. Please share the following:

1) Your undergrad GPA (you might also add major, type of school, progression, country, etc if you wish)
2) Dings you got (as well as any other factors besides a low GPA that might have come into play)
3) Schools you got admitted at

I know there are quite a few of us with a similar issue to overcome, so I thought it might be useful to organize what we know in one thread. Cmon on guys, give us some hope
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Hi everyone -- long time listener, first time poster! I have been silently absorbing all the great info on this forum throughout my process, but this topic really compelled me to register and contribute because low GPA was my #1 hurdle to getting into business school. A quick takeaway from my experience is that this is definitely a hurdle but NOT a barrier if you think strategically and put together an awesome application package.

I attended a small regional school (unranked nationally) where I majored in business no less, and came away with a low 3.01 GPA for a variety of reasons. Namely, my grades in quantitative courses were low and severely effected my overall GPA. I never admitted to my interest in graduate school because I didn't want to face my GPA and the application process. Finally, last year took the GMAT (700 score on the first try) and applied to business school in exasperation with my current job situation and prospects. Bad idea. I applied to Stanford (don't know why), Stern, and Kellogg. I was rejected from every single one which didn't surprise even me.

This year, I took a totally fresh approach. I researched schools extremely thoroughly and more importantly, spent a lot of time understanding my own strengths, weaknesses, career goals and future plans. I spoke with no less than two dozen people in various fields I was interested in until I had complete clarity into the right career path for myself and an understanding of how bschool fit into that journey. I knew that my story would be the key, so I spent months constantly working on essays to craft the best story possible. I chose only 2 trusted people to review my work over time until we all agreed what I had was near perfect. I always made sure though that no matter what edits were suggested, that the voice and content of the essays was 100% true to me. Also, I made it a point to apply as early as possible which I think helped tremendously.

In crafting my story, I also realized that my current work experience over 5 years is pretty kick ass compared to what a lot of other folks my age have been doing. I have taken on lots of leadership roles and driven tangible results for my company. So I spent an equal amount of time on my resume and created custom versions for each school based on what each tends to look for (based on many conversations with current students and alumni). I highlighted creative marketing projects more prominently on my Kellogg resume, while analytical and leadership projects reigned supreme on my Wharton resume.

Finally, I broke down what a poor GPA means to a school. It means that they're not sure of your general cognitive ability or capacity to succeed in courses and the impact you could have on fellow students. To combat this, I strategically chose two recommenders and asked them to heavily emphasize cognitive abilities to help correct the negative perception my GPA brings about. I took two finance courses, one online course offered by UC Berkeley and one at a local university. I worked very hard to get A's in these classes since I knew a B would really not help reverse negative perceptions. I also wrote the optional essay each school offers to explain a bit about my undergrad experience. I never made excuses but I explained some of the situation and how I know I didn't live up to my academic potential but wish to change that moving forward.

Last, I put it all together - strong resume, crystal clear essays, impressive recs (I hope, I didn't see them), supporting course work, strong EC's, and weak GPA.

Result? I got interviews from every school I applied to and ZERO rejections. In fact, I recently accepted a place with Wharton's class of 2013, one of the toughest evaluators of test scores, GPAs and analytical abilities. I hope this story will show you that an application can be more than the sum of its parts with a little strategic thinking, lots of advance planning time and determination.
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Concentration: Strategy, Marketing
GMAT 1: 690 Q V
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Thought I'd write my story here and the other low GPA thread since I read through all of the low GPA threads a bunch of times when applying because I was so nervous about my chances. Hopefully I will give another low GPA-er some hope!

Profile:
Age/gender: 28 y/o female
GPA: 2.9 from a top 10 liberal arts school, economics major
GMAT: 700 and 690 (yes did worse the second time), don't remember my split but my quant was nowhere near that 80% everyone says to get.
WE: 3 years in a rotational program for a well known financial services firm, 3 years in risk at a global investment bank
Extracurriculars: Captain of sports team in college, consistent volunteering since college (some leadership positions and unique stuff), very involved with former college, and have a lot of hobbies I mentioned in my apps to sort of differentiate myself.

Schools I applied to and results (all Rnd 1 or Regular Decision):

Wharton: Waitlisted (after a terrible interview mind you, Team Discussion was great, but interview, yikes)
Kellogg: Waitlisted
Columbia: Accepted
Fuqua: Accepted
Stern: Accepted

I think the following helped my case:

1. A clear idea/and description in my apps of my career goals, why an MBA would help them, why that specific school's MBA would help them, why now was the time I was pursuing MBA, and how my prior work experience would help me achieve those goals. I had heard that schools worry career changers won't find jobs if it is too great of a change, so I highlighted aspects/stories of my work experience that directly applies to my goals. I also made sure to show why I was passionate about my goals and what had led me to realize my goals.

2. In addition to tying my work experience to my goals, I tried to give examples of leadership at work. I told a couple of stories that demonstrated me taking initiative and leading teams. I also told my recommenders that schools like that so if they had any stories to put in their recommendations that would be great. Don't know what my recommenders ended up writing, but I did send them both an email with what my goals are and some of my professional and personal accomplishments.

3. Once you start doing in depth research on a school and its programs, it is pretty easy to figure out what is important to that school (what type of candidate they are looking for). So in each of my essays, I made sure to pick examples and tailor my message to that specific school's values.

4. I took two classes in the summer before I applied, 1 accounting class and 1 math class (not calculus level) to show that I have quant skills and can be a good student, got A's in both courses. Was told specifically by one of the schools that they really liked that I took the initiative to take those courses.

5. I visited every school I applied to. Luckily for me this was easy and the only two schools I really had to fly to were Duke and Kellogg which meant I could self-initiate an interview while I was there. Just felt like this showed my interest but more importantly allowed me to speak of my visit in my application.

6. In general I just really tried to show that I was ready to fully engage in the program and the school's community. Also tried to show a coherent story as to how my career goals were formed, how MBA would help achieve them, and what I hoped to do in the short term and long term.

7. Just a note about the optional essay since I wondered about this. I chose note to come right out and say "I have a low GPA because...". Instead I chose to use the essay to highlight the two courses I took in an effort to prepare myself for the rigors or the MBA program and since I had been out of school for awhile.

Hope that is helpful to someone! Nothing earth shattering above, but there are so many things to keep in mind and think about in this whole process it's easy to just get stuck on your low gpa or gmat and think that means you're not a strong candidate. Especially looking on this board, it's amazing how many people have such strong stats. But you never know, you see people with 750 GMATs and 3.8 GPAs get rejected from top schools all the time while someone with much lower stats gets in. To me, that really shows that the adcoms really do take a look at the holistic picture. Good luck!
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For anybody applying with a drastically low GPA, I can probably sympathize. Mine's is a long story of failure -> redemption and I'd like to share it with anyone who's interested in hearing about it. Here are my answers to the questions:

1) 2.6 GPA at top 25 public school (was on academic probation during senior year, no less). Basically completely lost my focus in school and went down the wrong path, hitting rock bottom. Had a dramatic revelation followed by personal transformation shortly afterward, part of which included attaining a top MBA as a long-term goal.

2) 7 years later, applied in FY 2008 (shot too high and dinged at all schools applied). For FY 2009- dings at Duke, Darden, Cornell, Kellogg.

3) I was R1 W/L at one of Yale-Tuck- Ross (won't say which, but really wanted to go there). After sending in pertinent waitlist update, I was accepted at start of R2 Matriculating for Fall of 2009.

Net results: Applied to 11 schools over 2 year span, dinged at 10, waitlisted at one, and accepted shortly thereafter.

Ultimately, I was able to make up for my low GPA but it was still an uphill battle because of it. Based on my own experiences, I do believe that all things are possible with the right frame of mind and some divine assistance as well.

PM me if you want more information on how I overcame the GPA issue.
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My story is different than most others here..... and please don't take my advice, I think I got lucky

29 year old Asian (born in US, grew up in New Zealand) living in LA

UG GPA (Operations Management/Statistics): around 2.6 to 2.7 (got better as the years went on), NZ uses a different scale, so not exactly sure
MSc GPA (Statistics): low 3s
GMAT: 700
WE: 5 years, biggest video game publisher, biggest entertainment/media company (in Video game division)

Applied to:
Duke - R2, invited to interview, accepted
MIT - R2, waitlist, ding
UCLA - R3, interviewed, withdrew

I wished I had applied to more schools, I studied for around 2 weeks and took the GMAT in Dec thinking I would need to retake anyway, turned out ok, didn't want to study again for a higher score (new born son to look after )
So I ended up with 2 weeks to write essays, again thought I would get dinged anyway so I didn't want to rush and apply to a lot of schools since writing the additional essay about how you have improved and not to mention new topics scared me.... So I only applied to two schools I really wanted to go to.
Didn't like my chances because of the following:
1) Didn't visit any schools nor attend any info sessions/lunch sessions/online chat, etc...
2) Low GPA, it got better as the years went on though (I failed like 4 papers in the first year... Diablo 2...)
3) No writing skills... no english related classes since form 6 in high school (2nd to last year)
4) Didn't have anyone to proof read my essays since I had such a short time frame
5) absolute zero community/extra-curricular activities though Under and Post Grad. (Video Games/Cars/Gambling was my life)
6) GMAT was ok... not excellent especially compared to most of people here.

Not saying my results were a huge success by most peoples standards here.. but here are what I think worked for me
1) I explained about my GPA - I played video games, as simple as that, I logged 600 real life days on Final Fantasy XI MMO during the last 10 years. Other people like doing community work, clubs, etc. I just like Video Games and Modifying cars.
2) My other essays were focused on things I really enjoy - Games and Fast cars and a little about family
I wrote about being one of the only 10 people in the FFXI server that has this sword which can only drop from a monster that comes out in game once every 3 real life days and the drop rate is around 10% if you do claim and kill the monster, then you have to win the dice roll for it against your team members... you do the math.
3) My recommenders were awesome, both have had their MBAs and have known me a long time and writes well
4) My essays were not proof read by anyone, I think that helped me.... it probably reads different than some really refined essays, I wrote more like how I speak in real life.
5) Maybe the Company I worked at are well know and that helps (not really sure about this one)
6) I wasn't really sure about putting down around 5 extra-curricular activities that were all things like FFXI guild leader, WOW guild member, Car clubs, but guess it didn't hurt me... better than blanks I guess
7) All the papers I failed, I had DNS (did not sit, which means I didn't even go to the exams, and all those papers I later got A's or high B's on, but yeah DNS really hurt my GPA). I guess this is a good sign? shows I can do the work, just that school wasn't most important, getting my Windforce in Diablo 2 was more important .. for all the Diablo players out there

So yeah, I hope anyone that reads this won't be put off trying to go to schools they dream about, it is very easy to do that if you read these forums a lot....
I would recommend writing the real you, show passion, and just try to show who you are.

Sometimes I think about applying to more schools this year since I will have more time to study GMAT, visit schools, network, etc. But what the hell, Duke is awesome, I was born there (left when I was 1 though) and I just don't want/have the time to study and write more essays... I have boxes of games I need to finish and a son to look after.

Best of luck to everyone applying

Last edited by lulumocha on 26 May 2011, 09:32, edited 1 time in total.
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Schools: Darden Class of 2011, Tuck, Duke, McCombs, HBS
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I'm going to add my own story to the mix...

I got a 2.8 GPA undergrad. I had a rough freshman year (I failed a high level calculus class 2nd semester) as I never learned a good work ethic. I was temporarily suspended from school (a good state school), but then came back and got on dean's list my first semester back. Unfortunately, I got lazy by the end and got just under a 3.0 my last semester in college.

My effort at work is completely different from that of my undergraduate career. I've worked for 4 years in Corp Finance at a media company and have been given an incredible amount of responsibility. Also, luckily, I scored a 750 on my GMAT (even though it took 3 times of taking it). I ended up applying to HBS (not sure why), Tuck, Darden, Fuqua, and McCombs. I was accepted at McCombs (with a bunch of money) and was waitlisted at Tuck, Darden, and Fuqua. I was recently accepted off the waitlist at Darden where I'll be matriculating.

I can offer the following advice for people with a low GPA. First, don't assume that it counts you out. I know I was waitlisted at the above schools due to my GPA (Tuck told me this), but if there's something else you can offer the school, they'll be willing to admit you. For me, I think it was my work experience, as it was very unique and my recommendations were very strong. Also, I genuinely enjoy interviewing, so I think that helped.

Also, try to find any sort of connections you have and ask for advice and ask if they can write a letter of support, it never hurts. If you're on the waitlist, don't be annoying, but try to keep a constant dialogue with the schools and give them a reason to admit you. Make it seem that it's their loss if they don't admit you. Lastly, don't give up. Getting in to school was really really hard (especially due to my GPA), but it's all worth it as I really loved Darden when I visited.

That's my story. Feel free to PM me if you have any other questions.

Matt
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Schools: Emory class of 2010
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I had a 2.88 undergrad GPA in Engineering, with 2 F's and it took me 6 years to graduate, and then another year and a half to get a job in the engineering field.

I applied to only one school and got in with a scholarship to Emory, and had an extremely successful first year, looking forward to my second.

Sometimes, I think schools are looking for someone who can overcome adversity and failure.
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Current Student
Joined: 05 Nov 2009
Posts: 171
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Schools: Oxford
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i think my gpa takes the cake on this one - 1.9 (and that's rounded up). a bunch of F's, especially in 2nd yr when i broke up with my ex and just didn't even sit for any of my finals.

i have pretty good work experience though and a 760 gmat.

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Oxford Round 1 - interview invite 10/30/09, admit 12/11/09, ATTENDING 2010

Current Student
Joined: 30 Jan 2010
Posts: 296
Location: United States
Concentration: Strategy, Economics
Schools: Chicago Booth - Class of 2015
GMAT 1: 770 Q V0
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I'm here to tell a story. A story about hard work and luck, but mostly luck. There's hope.

University: University of Southern California
Major(s): Mechanical Engineering
GPA: 2.88
GMAT: 770 (99%), Q:50 (93%), V:44 (97%), AWA:4.5 (37%)
Nationality: US, Caucasian
Age: 29
Gender: M

Application Results:
R3 - Fuqua - Dinged without interview
R3 - Ross - Accepted
R3 - Booth - Matriculated after being waitlisted
R3 - Kellogg - Withdrew from WL upon acceptance from Booth

My GPA was terrible, I applied in R3, and I certainly didn't have anything to offer in terms of demographic diversity. My GMAT obviously helped a ton and having significant work experience help distance me from my grades. Beyond that, my essays were solid and I very deliberately addressed my shortcomings. I took a risk for my 2nd rec by having a classmate from an executive education program I completed write about my contributions in an academic setting and devoted my optional essay to addressing my GPA and reasons for applying R3.

Good luck!
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2.999 undergrad GPA here... Ya, they actually list it as 2.999 on my transcript. How irritating is that?
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Not sure if this is "low" or not...

1. Undergrad GPA of 3.1, GPA in majors 3.7/3.8
2. Dinged at HBS (w/o interview), Columbia (w/ interview), MIT (w/o interview), Wharton (interview, WL, then ding)
3. Accepted at Booth, Kellogg, Duke, Tuck
Current Student
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1. Something like a 3.0 at a public ivy
2. Dinged at Stanford and Yale
3. Accepted at Virginia (w/scholarship), Duke (same), Texas, UNC (\$). Matriculating at Fuqua.

I feel like I had one kinda legit reason for the low GPA - I transferred schools after my first year, and my next school didn't count my first year GPA into my cumulative. I had a very successful first year and then took the two weed out courses for my major (Econ) in my first semester at the second school, so that hurt my average a lot, though I did better afterward.

All I did was write a little four-sentence blurb about this in the "any additional info" box on all my apps. Other than that, I didn't address it at all. My impression is that the more attention you draw to it, the more they'll think about it. The last thing you wanna do is come across as the little go-getter who's stressed out about how his/her UG GPA looks to B-schools - just concentrate on what you've done since then, and let that work speak for itself.
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Great thread. Had an unusual undergrad history myself. I'm one of those candidates that had to answer both the "Have you ever been on academic probation?" and "Have you ever been convicted of a crime?" questions

It took me 3 undergrad schools to graduate from college. (Withdrew from first school after a year, took non-degree classes at another while I tried to get back on track, and finally graduated from the 3rd.) Bizarre transcripts to say the least. While I was an excellent drinker and partier, these apparently are not officially recognized extracurricular activites in college Add in a run-in with the law in my early 20's after college - I've got a "colorful" past. GPA was technically a 3.3ish, but my transcripts oscillate between good grades and then periods of poor grades, incompletes and withdrawals. I was a bit of a mess back then.

GMAT: 720
Rejected: Last Year (2009-2010) - Kellogg, Booth, Yale
This Year: MIT
Accepted: Last Year - Nobody!
This Year: Ross, UNC, Emory, GT, waiting on one more

Utilized the additional essay to briefly own up to my past transgressions and reflect how they've increased my desire to attend bschool and pursue my current career goals.

Good luck to other prospective candidates!
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elleesie wrote:
As a fellow low GPA-er, this post has been incredibly inspiring! Hopefully, after I submit applications this fall/winter, I will have a success story to contribute.

Since so many of you are total success stories, I was wondering if you could give me some advice so I can look more appealing to the admissions committees when I apply.

I am a 31 year old female. I took the GMAT last month and scored a dismal 620 (V34 Q41 AWA6.0). I am currently in the process of studying my butt off so I can retest and hopefully break the 700 mark. I went to a UC, majored in Art History, and my overall undergrad GPA was 2.91. I struggled immensely my first two years of undergrad, but kicked things into gear the last two years and got a GPA of 3.76 (Dean's Honor list several times, GPA ranging from 3.49 to 4.0). I'm hoping that the adcoms will look at the overall improving trend in my GPA and put less emphasis on my overall GPA (which I will most definitely explain in an extra essay).

I would love to go to Fuqua or CBS, but I feel that those two schools are out of my league. Even Tepper would be a dream come true. However, I have my sights set on Marshall - USC since it is local to me, and I don't feel that going to school out of state is appropriate for me at this moment given personal circumstances. (Without going too much into detail, my father passed away suddenly 3 months ago, and I don't feel comfortable leaving my mother--who is still very depressed--by herself just yet).

I know that having an alternative transcript will help to boast my application and possibly put less emphasis on my undergraduate GPA. Online programs would be preferable, and I heard both Berkeley Extension and Thunderbird offer good courses to supplement my application. I'm thinking that taking a course or two this summer online could help for when I apply this fall/winter. What online programs and courses would be the most advisable to take? Keep in mind that I am an Art History major. I did take Calculus and Statistics and did well, but have no real educational experience in subjects like, Marketing, Finance, Accounting, etc (I can write a mean essay, though!)

Thank you so much for your help

You sound a lot like me. I'm a 31 year old female with a low GPA (although I'm a 2.7 with a downward trend). You wouldn't be matriculating til Fall 2013 so I wouldn't refrain from applying to your dream schools because of immediate circumstances. A lot can change in a year.

In my opinion your resume and career goals essay are going to make or break your application. Being older you're in this tricky spot where you are expected to have a good amount of career progression but not so much to make you seem more suited to a PT or E-MBA. It's definitely a tough balancing act. What company you work for and your role there will definitely matter a lot. I would focus a lot of your time on recommender prep. Other than that, do a good job of communicating your goals, leadership experiences, and self-awareness and I don't see why you wouldn't have a shot at Fuqua, CBS, or Tepper. May not be a slam dunk, but you'd give yourself a fighting chance.
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The Brain Dump - From Low GPA to Top MBA (Updated September 1, 2013) - A Few of My Favorite Things--> http://cheetarah1980.blogspot.com

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1. 3.17, Finance, Large State-School, (Two Fs on transcript)
2. Dinged at Booth and UCLA (Anderson)
3. Accepted at Texas and Matriculating at Kellogg

A low GPA can certainly be overcome. Remember, this isn't Yale Law School or Harvard Med School where one B will kill you.
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jb32 wrote:
1. 3.17, Finance, Large State-School, (Two Fs on transcript)
2. Dinged at Booth and UCLA (Anderson)
3. Accepted at Texas and Matriculating at Kellogg

A low GPA can certainly be overcome. Remember, this isn't Yale Law School or Harvard Med School where one B will kill you.

3.17, that doesn't count as low GPA.

Success stories would be more like zoinnk -Wharton (Mat)/ H (admit), sonibubu - Chicago (Mat)/Kellogg (admit) and sleepy - Georgetown (Mat). There is a low GPA success thread but I'm too lazy to find it. (that's probably why I have low GPA)
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2. Dinged at Ross (w/ interview) and Wharton (w/o interview)
3. Accepted at Duke and will be matriculating at Tuck

I should add that Tuck's average undergraduate GPA for those accepted this year was 3.5.

RF
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highhopes wrote:
rhyme wrote:
2.999 undergrad GPA here... Ya, they actually list it as 2.999 on my transcript. How irritating is that?

2.999? ridiculous, surely that rounds up.

You would think wouldn't ya? But nope, they actually list it as 2.999
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Toubab, I agree that drawing too much attention to your GPA is not necessarily the best idea, but that only works if your GPA is around 3.0. That in my books is not that low. Anything say 2.5 and below would probably be a sore spot to overcome and would definitely need to be addressed in a more thorough manner.
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Jeffelite wrote:
You guys should stat your GMAT score. I'm sure the guys with a low GPA had very high GMATs?

Most people have their GMAT score in the profile information listed to the left of their posts, and it looks like all the posters here have 700+. In general, a low GPA + below average (for the school you're applying to) GMAT is going to make it much harder to convince the adcom you're academically capable of handling their program. So it's no surprise that the people who have succeeded with low GPA have higher GMAT scores.
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# Low Undergrad GPA Success Stories

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text:
# Definition:Disconnected (Topology)/Set

## Definition

Let $T = \struct {S, \tau}$ be a topological space.

Let $H \subseteq S$ be a non-empty subset of $S$.

### Definition 1

$H$ is a disconnected set of $T$ if and only if it is not a connected set of $T$.

### Definition 2

$H$ is a disconnected set of $T$ if and only if there exist open sets $U$ and $V$ of $T$ such that:

$H \subseteq U \cup V$
$H \cap U \cap V = \O$
$U \cap H \ne \O$

and:

$V \cap H \ne \O$


text:
Kick back and get started at your own pace.

Given a 27-character alphabet and that the phrase to produce is 28 characters, simple combinatorics shows the possible combinations totals to $28^{27}$, or about $1.2\times10^{39}$. When factoring in the effect that the environment has in shaping the evolution of a species, the outcome is not based purely on chance. Life is plastic to its environment. A simulation of the Dawkins Weasel program is below.


text:
#### Solving simple stochastic games with few coin toss positions

##### Rasmus Ibsen-Jensen, Peter Bro Miltersen

Gimbert and Horn gave an algorithm for solving simple stochastic games with running time O(r! n) where n is the number of positions of the simple stochastic game and r is the number of its coin toss positions. Chatterjee et al. pointed out that a variant of strategy iteration can be implemented to solve this problem in time 4^r r^{O(1)} n^{O(1)}. In this paper, we show that an algorithm combining value iteration with retrograde analysis achieves a time bound of O(r 2^r (r log r + n)), thus improving both time bounds. While the algorithm is simple, the analysis leading to this time bound is involved, using techniques of extremal combinatorics to identify worst case instances for the algorithm.

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