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How To Download And Play Custom Zombie Maps.
Adiantku January 6, 2020 10 min read
You might be surprise but do you know that playing video games has its benefits? There's much debate over the potential benefits and risks of video gaming in children and teens. To provide some clarity, Jesus Pujol, MD, of the Hospital del Mar in Spain, and his colleagues investigated the relationship between weekly video game use and certain cognitive abilities and conduct-related problems. The vast majority of gamers I know are more like myself or my husband. They spend a bit of their free time with it, much like somebody else might use the time to watch TV, read a book, or organize their stamp collection. As long as your brother doesn't play to the point of losing his job, failing school, destroying relationships or sacrificing hygiene, I'd say don't worry about it. Pertama-tama, Jaka akan kasih tahu kamu rekomendasi game PC online terpopuler yang dimainkan oleh jutaan orang di seluruh dunia. The game has very similar gameplay to the Dungeon Keeper series and Theme Hospital (another of Bullfrog's strategy games). The game has players building their own lair while attempting to achieve world domination. In my own personal estimation, Mass Media goes along with Information and Communication Technology in this day and age so as to mold a new-fangled way of life to the majority living in this global generation. With the help of Game Copy Wizard, you can copy any video game in your personal collection. You can also copy many of your games directly onto writable media without any issue. It is yet to come across a built-in protection program on a game that is too difficult for Game Copy Wizard to break through too. I have been playing games that are long gone thanks to this excellent software. Even old records remain in my play list because of this new technology. Some superior gaming sites offer online gaming tournaments for the online Battleship game, for example. You might have played this fun game many times against the computer as your enemy, but what a great deal of excitement will be yours when you play with a real enemy opponent, who might physically be thousands of miles away from you. You could play against friends you have made playing online Battleship, or you might play against complete strangers. Either way, you will have a competitive time matching wits against other excellent players. Hikikomori is currently viewed as a sociocultural mental health phenomenon, rather than a distinct mental illness. Given at least 1.2{79210becb378e50578f72f1b1dd234c2c3483bafde9b186c9fb58315cd686901} of the population (around a million people) are affected, hikikomori is a significant social and health problem. Hikikomori is also increasingly being identified in other countries The term is now used across the world to describe anyone who fits the criteria.
PocketSlay, from Sean 'Connor's Windows Games (), is a strategy game with a medieval set, where the main island is divided up between the six players. The game objective is to try and capture the enemies' territories and link them up with your own to make it stronger. The game can be registered for $20. I so agree with you. I loved playing the game as a kid. It kept me off the streets, and kept my nose clean. I felt I owed Baseball something, so I Coached and Managed my kid's teams. But it seems as if the Major Leaguers do not feel an obligation to the sport. Instead, they feel it owes them something, and they will strip all they can out of the game to get it. The information comes way of an official PlayStation email that Sony has been sending to its developer and publisher partners that relayed word that starting on October 19, the web version of the storefront will no longer allow for the purchase of the following: PS3 games, PSP games, PS Vita games, PS4 apps, PS4 themes, and PS4 avatars. This same change will go into effect on mobile on October 28. Oddly enough, Sony is also removing the "Your Wishlist" feature. With the Internet it doesn't matter where in the world you live, every online casino would love to lure your custom. As a result you can get a comp simply for deciding to play at a given casino regardless of how much you've gambled there. The sign-up bonus is a common online attraction. It gives you a substantial value in real credits at the casino and you can exploit this bonus to swell your bankroll, spend more time playing the slots and experience more opportunities to be a winner. Viewer preference for right-wing US TV media is linked to significantly fewer preventive measures against COVID-19 and behaviours likely to increase the risk of infection, finds research published in the online journal BMJ Global Health. Gummy Drop is simply one of the best games to try if you want to play free match 3 games! In this one you will have to match at least three candies to make them disappear from the game board, and the more candies you will match the higher your score will be. But it's not as ordinary as it sounds, because in Gummy Drop you will re-build entire cities by matching candies and you will slowly complete the whole world map! This is a challenging yet very enjoyable game and it will provide you with long hours of entertainment. Tip: In this sequel, a new feature allows players to earn more gold if they harvest a crop early. The fresher the crop, the more money it will yield. Full-grown crops have a three yield cycle, which means it will remain fresh for only three hours if it takes one hour to completely grow. If you harvest a crop in the first hour, you will earn more. But if you harvest it in the third hour, you will receive half of the gold earned in the first hour.
I personally prefer LOTRO above and beyond all other MMO's. It's Tolkien design and themes follow the literary masterpiece so well. I've done beta testing for LOTRO, which I've been an active player since launch. Also tested on Star Wars Old Republic which I really enjoyed but left you with nowhere to go, Elder Scrolls which looks very promising and Warhammer. Warhammer was the most cartoonish of them all but still had fun pvp. Disney Epic Mickey 2: The Power of Two lets you play as Mickey Mouse and Oswald the Lucky Rabbit to explore the open-ended Disney world named Wasteland. Players can interact with the environment and blaze their own trail through each game level. Men In Black: Alien Crisis is a standalone story to Men In Black 3 and features the new MIB agent Peter Delacoeur as the main playable character. But if you happen to be weary about enjoying the lottery online, you may like to know that there are come ways that you can make sure that you are safe while you are playing. It is easy to understand why you might be weary, you never know if you are being scammed or not so it is better to avoid playing these games instead. The last way that we can play old games is the old fashioned way. That means picking up the console it was released on and a copy of the game itself and playing the thing as God intended. No downloading, no emulating, no tips or tricks or cheats. Just you and an old console and a dusty old cartridge and a wired controller. And there's something incredibly satisfying about that. What's the best way to kill some time than playing online casino games. Not only are they entertaining and fun, but they can actually allow people to earn a few dollars on the side. The only mobile gadget that could match it in terms of speed is ASUS' Transformer Prime The GPU (Graphics Processing Unit) is a top of the line SGX543MP4+. With all these hardware, expect only the most beautifully rendered games ever found on a mobile gaming device. Order Up!! is a cooking simulator of sorts where you prepare meals and manage a restaurant as an up-and-coming chef. Players also must compete in the "Fortified Chef Competition" earning them a chance to skyrocket their virtual culinary career to new heights. While The Camping Mod has its problems, it is easily one of the most important additions for players who wish to enjoy the wilds. Lanterns provide light for those wandering through the darkness, and campfires give the buffs and food needed to keep players healthy throughout the roughest of nights. Backpacks allow for great portable storage, knives let players create whatever they need to on the fly, and tents are wonderful little homes that require almost no time to construct. Whether one wishes to explore, travel, live outside, or simply seek shelter during a bad night, The Camping Mod provides everything needed to enjoy life in Minecraft's zombie-infested great outdoors.
One interesting aspect of the pitch restriction recommendations is that there is no consideration for number of pitches thrown in the bullpen or during before-inning warm-ups. Players may therefore be considered in the "safe" zone of pitches thrown when compared to state guidelines – when in reality, the pitching volume and unaccounted workload including the bullpen and before-inning warm-up pitches would be significantly higher than recommended. Since we all, depending on our age and experiences, have different ideas about how old something has to be to be old, there has to be some sort of objective rule. For my money, once a system has been discontinued by the manufacturer then we can safely call it old enough for playing it to be considered retrogaming. By that definition, the most recent console to fall under the umbrella of retrogaming would be the PlayStation 2, and while some of you might balk and scoff at that consider this; the PlayStation 2 was released sixteen years ago. Every few years another new console joins the ranks of retrogaming, and while they might not adhere to what our personal ideas of retrogaming are they still fit the criteria. So where an increase in media has led to the nationally recognised leagues and their top clubs to a larger fan base and games to be televised on satellite channels. If your game goes longer than 5-6 rounds, or if your opponent has quick removal early on, consider restarting. Your games should be quick creature advantage or you already lost and will waste time. Guild Wars 2 is set in the world of Tyria and aims to build on the features and story of the original Guild Wars, but you shouldn't feel pressured into playing the original just for the story's sake. Ability Power Per Level Glyphs support Evelynn's damage output throughout the game but can be replaced with Magic Resistance if you prefer a defensive option. The study did find that whether gaming against people or computers, levels of the hormone aldosterone decreased. This is the trickiest part and can confuse anyone. Some players get confused and are not careful when making a move. You should not forget, that there 5 chances that you will loose but only one chance that you will succeed. So be careful. According to the ACC tournament schedule, on Friday, North Carolina is playing against Florida State, Virgina Tech is up against Miami, Duke versus Virginia and Clemson against Maryland. Wait no further and do not miss the games. The new study builds on previous work by Bavelier and colleagues that showed that video games improve vision by making players more sensitive to slightly different shades of color.
To unlock cards you will have the option to play a story mode, "explore each plane when they are unlocked", and multiplayer matches. I would suggest going through the story mode and at least unlock all of the planes first. After that is complete you can grind the "explore" mode in each plane to unlock each card for each plane. Then once you only have the Battle Boosters left, go online and play against real people (you will have a more competitive deck if you wait until all the offline cards are unlocked first). I'm not much of a game player, but I can imagine that people can get hooked to them. Looks good. Mutant Nightmare ushers in an end of an era for TMNT games for two reasons: it would be the very last console title to feature the 2003 TMNT series as an influence, and it would be the very last TMNT game to be developed by Konami. Mutant Nightmare follows the third season of the animated series, and gameplay lines up accordingly with the other two sixth-gen TMNT console entries. There really aren't any surprises with this one, and those who loved Battle Nexus and 2003's Teenage Mutant Ninja Turtles will likely love this one, and those who hated the previous entries are bound to despise this one. Critics were, predictably, harsh towards Mutant Nightmare, and most attested disdain towards the fact that it brought absolutely nothing new to the table. The main reason people sometimes feel aggrieved when playing Golf Clash is the tournament results. If you shoot your best ever round but you're still five shots behind the leader this does make you feel as if they may be cheating. Well the news is that there is a form of cheating that is commonly used in Golf Clash. This is known as sandbagging. Maybe you are a soccer fan but do not like to watch Basketball. Or maybe you follow every NBA game but have never seen a sport played on ice. There are lots of different sports that fans can follow and it is the same when it comes to esports. If you are into fighting games you can watch Street Fighter in tournaments like Evo. Evo happens in Vegas every year and is the biggest event for fighting games. For fans of first person shooters like is Call Of Duty or Cs:GO. Of course you have Fortnite for people who like to watch battle royale type games. And for the MOBA fans you don't get more popular than DOTA 2. Some games are more watched than others but there is something for every fan. Lucent Singularity is your main damage source so it is maxed first, second you should consider Light Binding for the increased damage. If you are playing support Lux you can consider maxing Prismatic Barrier second instead for the increased damage absorbing it offers.
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Twenty-three New Cases of COVID-19
COVID - 19 / Health and Wellness
April 24, 2020 - 11:30 AM
As of today, April 24, Nova Scotia has confirmed 850 confirmed cases of COVID-19. Twenty-three new cases were identified Thursday, April 23.
The QEII Health Sciences Centre's microbiology lab completed 888 Nova Scotia tests on Thursday, April 23 and is operating 24-hours. Nova Scotia has conducted more COVID-19 tests per capita than any other province.
As of April 23, there were 10 licensed long-term care homes and unlicensed seniors' facilities in Nova Scotia with cases of COVID-19, involving 189 residents and 82 staff.
While most cases in Nova Scotia have been connected to travel or a known case, there is now community spread. That is why travel has been removed as a requirement for testing for COVID-19.
The list of symptoms being screened for has recently expanded. If you have two or more of the following symptoms, visit https://811.novascotia.ca to determine if you should call 811 for further assessment:
new or worsening cough
To date, Nova Scotia has 24,521 negative test results, 850 positive COVID-19 test results and 16 deaths. Confirmed cases range in age from under 10 to over 90. Eleven individuals are currently in hospital, three of those in ICU. Three hundred and ninety-two individuals have now recovered and their cases of COVID-19 are considered resolved. Cases have been identified in all parts of the province. A map and graphic presentation of the case data is available at https://novascotia.ca/coronavirus/data .
Public health is working to identify and test people who may have come in close contact with the confirmed cases. Those individuals who have been confirmed are being directed to self-isolate at home, away from the public, for 14 days.
Anyone who has travelled outside Nova Scotia must self-isolate for 14 days. As always, any Nova Scotian who develops symptoms of acute respiratory illness should limit their contact with others until they feel better.
It is now more important than ever for Nova Scotians to strictly adhere to the public health orders and directives - practise good hygiene, maintain a physical distance of two metres or six feet from others, limit essential gatherings to no more than five people and stay at home as much as possible.
Nova Scotians can find accurate, up-to-date information, handwashing posters and fact sheets at https://novascotia.ca/coronavirus .
testing numbers are updated daily at https://novascotia.ca/coronavirus
a state of emergency was declared under the Emergency Management Act on March 22 and extended to May 3
Government of Canada: https://canada.ca/coronavirus
Government of Canada toll-free information line 1-833-784-4397
The Mental Health Provincial Crisis Line is available 24/7 to anyone experiencing a mental health or addictions crisis, or someone concerned about them, by calling 1-888-429-8167 (toll free).
Kids Help Phone is available 24/7, by calling 1-800-668-6868 (toll-free).
For help or information about domestic violence 24/7, call 1-855-225-0220 (toll-free).
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Archive: news releases from 1995-97
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Finally! You and your best buds have a few extra days of vacation time saved up – no weddings or baby showers to attend, and a few extra bucks in the bank. You're all dying to take the ultimate girls' trip, but the big question is: where in the world should you go? Even if your tastes are all over the map, these hotspots make the ideal retreat. Whether you want to hit up a club, chillax by the pool or do nothing at all, all five deliver the one thing that any girl group needs to be happy on vacay—options.
It's nearly impossible for you and your girls not to be charmed by the Crescent City's rich history, renowned jazz scene and incomparable Cajun cooking. But while it's long on culture, this town has always known how to throw once heck a party (so get plenty of sleep before you arrive!). Want to be located right in the thick of things? Book your stay at the Hotel Monteleone, a famed literary landmark that once played host to the likes of William Faulkner and Truman Capote. While it's located on Royal, the most upscale shopping street in the Quarter, it's just one short block away from the revelry of Bourbon. Dance on a balcony, try a neon-yellow hand-grenade, or make a break for the nearby Faubourg Marigny. In this hip neighborhood, you can join the locals in listening to live bands play at d.b.a., Snug Harbor and Blue Nile.
Trip Tip: Jump on the streetcar and ride it from the Quarter toward Tulane. The gorgeous Victorian mansions you'll spot in the Garden District represent some of America's best-preserved southern architecture.
Of all the Caribbean's many gorgeous isles, this one is our fave for group getaways. Besides being ultra-safe (locals rarely lock their doors) and boasting one of the longest unbroken stretches of white sand beach in the region (seven miles from end to end!), Grand Cayman takes top prize for its unparalleled scuba diving. Not certified? Get your friends together to do the classroom training at home, then get your degree in one of the world's most revered underwater locales. As you descend to new depths in bathtub warm seas, you'll come face-to-face with schools of florescent tropical fish, green and hawksbill sea turtles, eagle rays, lobsters and barracuda. One little-known benefit of diving is that it burns a ton of calories, so you'll be more than justified in treating yourselves to a massive brunch. The best on one this island can be found at The Ritz Carlton Grand Cayman.
Trip tip: Take a short boat ride to Stringray City, a shallow water area where dozens of curious rays swim right through crowds of shrieking visitors. Don't worry: They're friendly, and will literally eat out of the palm of your hand (if you're feeling extra bold, ask your guide to show you how!).
When it comes to the ultimate girls' adventure, Vegas delivers big on the four S's: Sun, Scene, Spas and of course, Sin. Kick off your trip by checking into the new all-suite tower at the Hard Rock Hotel & Casino—stay in one of the sophisticated "standard" rooms or splurge on spa villa which opens up directly onto one of the pools. Also within the hotel, you'll find three of hottest clubs in Vegas (including Vanity, Rehab and the newest edition, SKYBAR), the Reliquary Water Sanctuary & Spa and of course, tons tables and games where you can meet other players and perhaps, get lucky yourself.
Trip Tip: Want a sure bet? You can save 30 percent on your stay at the Hard Rock (plus 25 percent at the MGM Grand and the Mirage) if you book with the new ZYNC card from American Express (just be sure to add the "Vegas Pack" to get the discount). You'll also get spa, entertainment and beverage credits, plus complimentary access to the Vegas.com concierge service.
Sure, this surreally beautiful destination, located just north of San Francisco, is renowned for top-notch Cabernets and Sauvignon Blancs (and we suggest trying them all!) but there's much more to do here than simply sampling wine. From your ultra-cozy home base at the Harvest Inn in St Helena, it's just a five minutes drive to the Culinary Institute of America, where you can sign up for a 30-minute chocolate tasting, take a full-day cooking class or have an incredible multi-course meal at the school's Wine Spectator restaurant. Since serious relaxation should be part of any girls' getaway, treat yourself to a half-day "Spa Girl" pampering package at Silverado Resort in Napa. When you add the Spa Pack to your ZYNC Card before you take off—and book through SpaFinder.com—you'll save 10 percent on any treatment.
Trip Tip: Got a few extra days to spare? Rent a car and head down to San Francisco. You can check out shops (and the seals!) at Fisherman's Wharf, bike ride over the Golden Gate Bridge, take a cable car tour of the city or a day trip to Alcatraz.
Full disclosure: NYC is this writer's hometown, so I'm more than a little partial to its city-that-never-sleeps appeal (that vibe is part of why I moved here!). Nowhere in the world can you and your girlfriends stay in such ultra-chic digs (my current faves: The Gansevoort Park and The Setai both located in the trendy new neighborhood known as "NoMad") and dance 'til dawn and beyond at clubs like Kiss n' Fly, Ceilo and Tenjune, all located within Manhattan's Meatpacking District.
Trip Tip: No matter which carrier you fly, you'll score double points on your Big Apple airfare if you add the Go Pack to your ZYNC Card before you book. If possible, try to fly in to LaGuardia, which is the closest airport to the city (you can spend the $20 you save on a cocktail or two!).
I have always heard that Grand Cayman was beautiful. I am so glad you pointed out safe because that is a very important and often overlooked factor.


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Read paper.dvi text version
Low-Cost, High-Fidelity, Adaptive Cancellation of Periodic 60 Hz Noise$
Kyle D. Wesson,a , Robert M. Ochshornb , Bruce R. Landc
Department of Electrical and Computer Engineering, Engineering Science Building, University of Texas at Austin, Austin, TX 78712 b Center for Advanced Visual Studies, Building N52-398, Massachusetts Institute of Technology, Cambridge, MA 02139 c School of Electrical and Computer Engineering, Phillips Hall, Cornell University College of Engineering, Ithaca, NY 14853
Abstract A common method to eliminate unwanted power line interference in neurobiology laboratories where sensitive electronic signals are measured is with a notch filter. However a fixed-frequency notch filter cannot remove all power line noise contamination since inherent frequency and phase variations exist in the contaminating signal. One way to overcome the limitations of a fixedfrequency notch filter is with adaptive noise cancellation. Adaptive noise cancellation is an active approach that uses feedback to create a signal that when summed with the contaminated signal destructively interferes with the noise component leaving only the desired signal. We have implemented an optimized least mean square adaptive noise cancellation algorithm on a lowcost 16 MHz, 8-bit microcontroller to adaptively cancel periodic 60 Hz noise. In our implementation, we achieve between 20 and 25 dB of cancellation of the 60 Hz noise component. Key words: adaptive noise cancellation, embedded signal processing, noise cancellation on microcontroller, electrical interference
This work is a collaborative effort that took place from Spring 2008 to Fall 2009 at Cornell University.  Corresponding Author Email addresses: [email protected] (Kyle D. Wesson), [email protected] (Robert M. Ochshorn), [email protected] (Bruce R. Land)
Preprint submitted to Journal of Neuroscience Methods
1. Introduction 60 Hz power line noise contamination can completely overwhelm signals of interest making sensitive or low-voltage measurements nearly impossible. This situation occurs in neurobiology laboratories when trying to make accurate measurements of low-voltage processes such as action potentials from nerve cells or when taking an electrocardiogram. It also affects other laboratory environments such as industrial instrumentation or chemical voltimetry which are high impedance measurements and, thus, noise sensitive. A common way to eliminate the 60 Hz AC power line noise1 from the signal of interest is with a fixed-frequency notch filter. The ideal notch filter has a flat frequency response over all frequencies of interest except at 60 Hz where the frequency response is zero. The ideal case cannot be achieved because any realizable notch filter will have two undesirable traits. First, the frequency response will not be flat, especially near the attenuated frequency where ringing occurs. Second, the notch frequency cannot vary and, thus, cannot attenuate noise with frequency shifts.2 Studies have shown that the frequencies in 60 Hz power line references can vary as much as ±1 Hz (Ramos, M`nuel-L`zaro, R` and Olivar, 2007) making the notch filter unsuitable. a a io, Widening the notch to include 5961 Hz will attenuate some of the desired signal and is thus impractical. Adaptive noise cancellation systems can overcome the issues faced by the notch filter, and the underlying theory is well studied (Kuo and Morgan, 1996). In fact, much research has gone into digital notch filters with adaptive control over their variables (Ferdjallah and Barr, 1994). Typically, moving away from simple analog solutions leads to complicated implementation and a higher price tag. Although commercial systems such as "The Humbug" (Scientific, 2008) are available and adaptive noise cancellation systems have been implemented on DSPs or a FPGAs, these alternatives are expensive. Our method and implementation, using a low-cost microcontroller, is an excellent option for laboratory or classroom work on a budget because it can adapt to frequency variations in the noise and is a low-cost3 alternative to
60 Hz power line noise is the focus of this paper although this method can be quickly and easily adapted in software to cancel 50 Hz line noise found in Europe. 2 Actually, analog filters can vary due to aging and temperature shifts, but this is rarely desired behavior (Lynn, 1977). 3 By using the phrase "low cost," we are not referring to a commercial production unit,
commercial systems. Our design is unique because unlike FPGA implementations (Ramos et al., 2007; Stefano, Scaglione, and Giaconia, 2005; Elhossini, Areibi, and Dony, 2006), our design maintains the signal in analog at full fidelity and passes the signal through the system with virtually no delay. And unlike direct sine-wave generation filtering techniques, as proposed by Ahlstrom and Tompkins (1985), our system can respond to the non-sinusoidal properties of powerline interference (Fig. 7 shows the complexity and higher harmonics of AC-line noise). Our implementation uses an optimized least mean squares (LMS) adaptive filter (Kuo and Morgan, 1996). The goal is to periodically update a set of weights that modify the system output to minimize unwanted noise by eliminating the correlation between the error and reference signals. The output of the system (also known as the error signal) is fed back into the filter which modifies its weights according to the calculated correlation and optimized LMS algorithm. Sec 2.3 describes LMS algorithm modification and optimization required to implement it on a microcontroller. 2. Materials and Methods 2.1. High-Level Design The goal of our cancellation system is to remove the correlation between the 60 Hz contaminated signal and the 60 Hz reference. The paper uses the following signal naming conventions: · the noisy or contaminated signal is the signal to "clean" that has not gone through the system and contains unwanted AC line noise; · the 60 Hz reference is the noise reference obtained from the power line; · the "antinoise" is the signal that is generated on the microcontroller through the LMS algorithm and created using pulse width modulation;
which may very well have high research, development, and marketing costs. Instead, we are referring to the "do-it-yourself" creation and implementation of active noise cancellation in situations where the purchase of high-cost commercial units is not feasible. It is the authors' hope that this device can be built from the specifications in this paper (either by students in an educational laboratory or by researchers on a budget) to gain capabilities once available only to those paying for a high cost commercial system.
· the output, error, or clean signal is the noise-free signal that is the endresult of the system. Although the goal is to have a noise-free result, the clean signal is used in the feedback loop and thus is confusingly called the error signal. The microcontroller receives a 60 Hz reference signal (from the wall power line) and outputs a 180 -out-of-phase sinusoid. This "antinoise" is then added in analog to the contaminated signal, effectively subtracting the interfering 60 Hz component and eliminating the line noise in the contaminated signal. The feedback loop is then formed by inputting the cleaned signal back into the microcontroller as the error signal. The microcontroller uses this input to update the weights that change the amplitude and phase of the antinoise signal as needed to eliminate any remaining correlation. A block diagram of the overall system at a high-level is shown in Fig. 1. 2.2. Hardware Overview The basic hardware components include an operational amplifier adder circuit, two RC-lowpass filters, a circuit to obtain the reference signal (voltage divider and bias circuit), and supporting circuitry for the microcontroller (Horowitz and Hill, 1989). The circuit schematic is shown in Fig. 3 (all resistors are 5% tolerance) and fits on a wallet-sized custom printed circuit board (PCB) shown in Fig. 2. The device is powered with a 120 VAC transformer that outputs 12 VAC from which we derive the 60 Hz reference signal and 12 and 5 VDC power supplies. The device is designed with the intent to minimize any spurious system noise during adaptive noise cancellation. On the board, a ground plane lies under all non-microcontroller circuitry to reduce spike noise that the microcontroller or other sources of broadband electromagnetic interference (EMI) might introduce into the system. Signal traces on the PCB are of minimum length to limit the total path length through the system and are kept far away from any power sources on the PCB to reduce the chance of reintroducing line-noise. We use an Atmel ATmega32 microcontroller, which is capable of 8-bit operation at 16 MHz. Microcontroller capabilities needed for our implementation include: · a pulse width modulation (PWM) channel for producing the antinoise signal 4
· two 8-bit (or better) analog-to-digital converter (ADC) inputs, to measure the reference and error signals · two 8-bit timer/counters with separate prescalers and compare modes, to schedule input to and output from the microcontroller The ATmega32's internal reference voltage is set to 2.56 V which means that the voltage range for inputs is 02.56 V. This requires the contaminated signal (and the reference signal) are biased to 1.25 VDC and are limited to ±1 V before input to the system. 2.2.1. Microcontroller Circuitry The initial PC board design came from the eighth revision of a prototype board used for the ATmega32 in a classroom context.4 Power to the board is derived from a 12 VAC transformer connected to the AC line. We also use this power source to obtain a reference signal and thus require the power input to be AC. However, for the power circuit, we pass the AC signal through a general-purpose 1N4001 diode (rectifier) to obtain DC voltage. The DC voltage is then passed into a 5 V regulator (LM340LA2) which distributes power to the ATmega32. Included in this path are several small capacitors. The board also includes a 6-pin header to program this chip on the PC board and the ability for serial communications through an RS232 serial port for debugging purposes. 2.2.2. Adaptive Noise Cancellation Circuitry The adaptive noise cancellation circuitry consists of circuits to obtain the 60 Hz noise reference, the analog adder, and two lowpass circuits. The 12 VAC transformer output powers the microcontroller and also serves as the 60 Hz reference signal. The 12 VAC signal is passed through two stages: a voltage divider stage to bring the voltage range down to approximately ±1 V peak-to-peak and then a biasing circuit to bias the reference with a DC offset of approximately 1.25 VDC to meet the input requirements of the ATmega32 ADC. The values of the pulldown resistors are 10 k, the pullup resistor in the voltage divider is a 100 k, and the pullup resistor in the biasing circuit is a 81 k.
4 The latest version of the prototype board, schematics, and assembly instructions can be found at http://www.nbb.cornell.edu/neurobio/land/PROJECTS/Protoboard476
There is a 2.5 µF capacitor between the voltage divider and bias stages that creates a high-pass circuit to eliminate DC bias in the reference signal. The capacitance value is chosen such that the 3 dB cutoff frequency of the biasing circuit with the resistors seen in small signal parallel occurs at 7 Hz. The analog adder is a standard unity gain inverting adder circuit followed by a unity gain inverting stage (overall non-inverting). The operational amplifiers are LM358 dual operational amplifiers in 8-pin DIP packaging. The input and feedback resistors are 20 k. The inputs to the adder are the contaminated signal and the antinoise from the microcontroller PWM channel after it has been lowpass filtered with a simple RC filter. The output of the analog adder is the clean signal (system output). Standard RC lowpass filters are used in two locations on the board. One lowpass filter is placed between the ATmega32's ADC and the error signal to eliminate possible high frequency content in the clean signal from aliasing down to the 60 Hz frequency and to comply with the sampling capabilities of the ATmega32's ADC. The second lowpass filter is placed between the output of the ATmega32's PWM output and the analog adder to smooth the signal into a sinusoidal waveform. Each RC lowpass circuit has a 20 k resistor and a 0.04 µF capacitor to provide a 3 dB rolloff at 200 Hz. A unique feature of our design and implementation is that the contaminated signal is never digitized--the entire signal path remains in analog. This allows for a much lower digitization rate and thus avoids loss of fidelity, delay, and sampling or reconstruction errors. The clean signal is sampled after low pass filtering in the feedback loop but only to modify the tap weights that control the antinoise. This does not effect the output signal bandwidth. 2.3. Software Overview The software is responsible for generating an antinoise signal and making realtime adjustments based on both the reference 60 Hz noise and the error signal.5 An optimized LMS algorithm minimizes correlation between the reference and error signals by adjusting weights W1 , W2 , . . . , WN . These comprise a finite impulse response (FIR) filter on past reference inputs R1 , R2 , . . . , RN to produce an antinoise output, antinoise which is summed in analog to
For those wishing to build the device on their own, our microcontroller code is available at http://www.nbb.cornell.edu/neurobio/land/Papers/AdaptiveNoiseControl.
the contaminated input to produce the system output, which we feed back in as our error measurement, error. Our software is structured into three primary components: 1. a timer interrupt that writes antinoise to PWM output at full clock speed with an interrupt triggered on counter overflow; 2. a timer interrupt with a clk/64 prescaler that performs ADC, alternatively storing the a measurement of the reference source Rn in a circular buffer, and storing the instantaneous system error, error; 3. finally, a main loop polls for state information which is set during the second timer interrupt and either updates filter weights when there is a new error value, or computes the next value of antinoise when a new value from the reference input is read. 2.3.1. Generating the antinoise We implemented a microcontroller-based, fixed-point adaptive FIR filter, so we compute output by summing the product of weights and previous values of the reference input:
antinoise =
W [i]R[i]
To avoid an undesired high-frequency harmonic, we output our signal pulse width modulated at the maximum rate supported by the ATmega32: 62,500 Hz. We do this through an interrupt, which linearly interpolates between desired outputs. Since the sample rate (see below) and the output rate are related by a power of two, we can find an appropriate increment for the interpolation with a simple right shift. 2.3.2. Filter Characteristics Since we are targeting 60 Hz noise (although this can be modified for 50 Hz line noise), we can optimize our filter for that purpose. We have a filter length of eight, at a sample rate for the input of 488 Hz, which gives an ideal window size of 488/8 = 61 Hz. This means that each sample is 45 apart in the 60 Hz reference signal, producing ideal conditions for adapting. In order to eliminate any possible aliasing in the error signal, we need to sample at a rate consistent with the Nyquist theorem. Since our cancellation focused on 5070 Hz signals, our input sampling frequency needs to be at least 140 Hz, and we need to lowpass the contaminated signal. 7
2.3.3. Adapting Weights We are using an optimized LMS algorithm based on Stefano et al. (2005) where weights are updated such that: Wn+1 = Wn + µ · error · Rn (2)
A further optimization that we employ replaces error with its sign (Stefano et al., 2005): Wn+1 = Wn + µ · sign(error) · Rn (3)
By achieving a small µ through adding the full Rn value to the fractional section of the weight, Wn+1 , (see Sec 2.3.4), we can eliminate all of the computationally-costly multiplications from the filter convergence, so that it runs on a low-speed microcontroller. 2.3.4. Fixed-point Math Floating point arithmetic is not practical with the computational limitations of a low-cost microcontroller and the speed required in a realtime system. We used a 16:16 fixed-point system, which devotes 16 bits to a signed integer component of the number, and 16 for the fractional component. Since all of our inputs were coming in from the internal ADC in eight bits, we only need define fixed-point multiplication with an eight-bit unsigned integer (ie. 8:0 fixed-point). 3. Results We present four tests to demonstrate the abilities and effectiveness of our adaptive noise cancellation (ANC) system. The first three tests are aimed at demonstrating the system's abilities through somewhat contrived examples whereas the fourth is a simulation of a neurobiological laboratory experiment. 3.1. Pure Frequency Signal Test To construct the pure frequency signal test, a single frequency signal is added to a 60 Hz noise signal to form the contaminated signal. The voltages of the two components can be varied to achieve the desired signal to noise ratio (SNR) for testing and evaluation. The goal is to have the pure single frequency as system output without the 60 Hz signal.
As an example, a 0.8 V peak-to-peak 200 Hz signal is added to a 0.8 V peak-to-peak 60 Hz signal to create the contaminated signal with a SNR equal to 1. The contaminated signal and 60 Hz reference are system inputs. The ANC system input and output over time is shown in Fig. 4. The top of the figure shows the contaminated signal and the bottom shows the clean signal (output) of the system after convergence. The frequency domain view of the cancellation is shown in Fig. 5 and allows us to quantify the cancellation. The top shows the FFT of the contaminated signal, and the bottom shows the FFT of the clean output. There is about 25 dB of cancellation of the 60 Hz component. Note that the system is designed to adapt to various amplitudes of 60 Hz line noise equally well (ie. over all amplitudes of noise). However, the system does have suppression level limits that are functions of the microcontroller. First, the microcontroller has a input range of 02.56 VDC. Because input signals are biased to approximately 1.25 VDC, the line-noise contaminated signal cannot exceed the approximately 1.25 V available range. The upper bound on the voltage range of cancellation is therefore limited to approximately 1.25 V peak amplitude. Second, the microcontroller has an 8-bit analog digitizer which limits resolution to about 1/256 of full scale or about -24 dB. Of the two factors, the latter is likely the limiting factor in our results since the contaminated test signal voltage range falls within the acceptable input specifications. 3.2. Convergence Test The convergence rate of the system--how fast it can achieve suitable cancellation--is also measured. The convergence rate is controlled by the software variable µ, which controls step size. With a moderate setting of µ, the system was stable and converged within three seconds. Convergence for AC line noise alone is shown in Fig. 6. 3.3. AC Line Spectrum We also put pure AC line noise into our system to determine how well the system reduced noise alone. Fig. 7 shows the AC line spectrum before (top) and after (bottom) cancellation. Cancellation of the fundamental 60 Hz signal is reduced by more than 25 dB. A typical notch filter implementation achieves only about 15 dB (Ramos et al., 2007).
3.4. Action Potential Test Although the first examples are not likely to be encountered in the laboratory, they are useful to obtain a sense of the overall performance metrics of our ANC system. A simulation of a neurobiology experiment is now presented. A typical laboratory experiment might be to measure an action potential-- an electrical signal generated and transmitted by nerve cells. Because of the power line noise in laboratories and the low voltage measurements trying to be performed, the 60 Hz noise can easily overwhelm the action potential. In order to simulate these conditions, we wrote a script to generate random action potentials of simulated electric organ discharge and then summed this with a 60 Hz signal from the AC line at a SNR of about 3/2 (top of Fig. 8). After the system converged, action potentials without noise are recovered (bottom of Fig. 8). 4. Discussion The noise cancellation system described is a low-cost alternative to commercial units (Scientific, 2008). Using low-cost commodity microcontrollers and analog summation, the device produces 2025 dB of cancellation of a pure 60 Hz sine wave while giving an analog bandpass of greater than 50 kHz. It can easily be modified to cancel 50 Hz with a software change to the sample rate. The limitation of our system is that only the primary 60 Hz harmonic is canceled. Second and third harmonics are attenuated up to 3 dB, and spike noise and other line-correlated noise cannot be canceled. The limitation is due to the relatively low computational rate of the microcontroller which limits the length of the FIR filter. However this limitation is not important in most lab situations. The distortion standard for line power (IEEE-519) specifies that the total harmonic distortion should be about 26 dB below the fundamental including up to the 11th harmonic. Measurements in our electrophysiology laboratory (late 1970's design with 3-phase 480 volt motors for air handling) showed 3rd and 5th harmonics to be 2430 dB below the 60 Hz fundamental at various times with very small 2nd and 4th harmonics. Measurements in a student electronics lab showed almost equal 2nd and 3rd harmonics at about -21 dB. Our circuit essentially removes the 60Hz fundamental by 2025 dB and attenuates the 2nd and 3rd harmonics up to 3 dB. 10
We foresee use of this system in student laboratories and other situations where low cost and adequate performance are important. Students should certainly be taught how to debug and minimize noise situations (e.g. multiple grounds and use of Faraday shielding) but should also see that active techniques can result in faster setup times and cleaner results. The system is adequate to `clean up' spike trains contaminated by 60 Hz with twice the amplitude of the spike train. Simulated spikes (but real AC noise) at a SNR equal to 1, which would render a spike threshold measurement useless, become clean enough to resolve 10% differences in spike amplitude. Acknowledgments We wish to thank Cornell University for the generous use of their teaching facilities and laboratory supplies. Additionally, we want to thank the developers of the free software AVR-GCC compiler and AVRDUDE programmer, whose tools were indispensable. We also thank Ben Arthur, Boris Chagnaud, Aaron Rice, and the anonymous reviewers for their thoughtful comments and revisions. References M. L. Ahlstrom and W. J. Tompkins. Digital filters for real-time ECG signal processing using microprocessors. IEEE Transactions on Biomedical Engineering, 32(9):708713, September 1985. Ahmen Elhossini, Shawki Areibi, and Robert Dony. An FPGA Implementation of the LMS Adaptive Filter for Audio Processing. In Proc. IEEE International Conference on Reconfigurable Computing and FPGA's, pages 18, September 2006. M. Ferdjallah and R.E. Barr. Adaptive digital notch filter design on the unit circle for the removal of powerline noise from biomedical signals. IEEE Transactions on Biomedical Engineering, 41(6):529536, June 1994. P. Horowitz and W. Hill. The Art of Electronics. Cambridge University Press, New York, NY, USA, 1989. Sen M. Kuo and Dennis R. Morgan. Active Noise Control Systems: Algorithms and DSP Implementations. Wiley Series in Telecommunications and Signal Processing. Wiley & Sons, 1996. 11
P. A. Lynn. Online digital filters for biological signals: some fast designs for a small computer. Medical and Biological Engineering and Computing, 15 (5):534540, September 1977. Rafael Ramos, Antoni M`nuel-L`zaro, Joaqu´ Del R` and Gerard Olivar. a a in io, FPGA-Based Implementation of an Adaptive Canceller for 50/60-Hz Interference in Electrocardiography. IEEE Transactions on Instrumentation and Measurement, 56(6):26332640, December 2007. Quest Scientific. Hum Bug Noise Eliminator, 2008. URL http://www.digitimer.com/research/quest/. Promotional Material. Antonio Di Stefano, Alessandro Scaglione, and Costantino Giaconia. Efficient FPGA Implementation of an Adaptive Noise Canceller. In International Workshop on Computer Architectures for Machine Perception, pages 87 89, July 2005.
Figure 1: High-level block diagram overview.
Figure 2: The PCB implementation of the adaptive noise cancellation system.
Figure 3: The PCB schematic.
Contaminated Signal; SNR = 1 0.4 0.2 volts (V) 0 -0.2 -0.4
0.025 0.03 0.035 time (s) Output Signal after ANC
0.4 0.2 volts (V) 0 -0.2 -0.4
0.025 0.03 time (s)
Figure 4: Time domain view of pure tone cancellation.
DFT of Contaminated Signal (200 Hz + 60 Hz; SNR = 1) 0.2 0.15 volts (V) 0.1 0.05 0
100 120 140 160 180 200 220 frequency (Hz) DFT of Clean Signal (200 Hz; 60 Hz reduced 25 dB)
0.2 0.15 volts (V) 0.1 0.05 0
100 120 140 160 frequency (Hz)
Figure 5: Frequency domain view of pure tone cancellation.
Convergence Rate for AC Line (60 Hz) Noise 1 0.8 0.6 0.4 volts (V) 0.2 0 -0.2 -0.4 -0.6 0 1 2 3 4 time (s) 5 6 7 8
Figure 6: Convergence rate for pure AC 60 Hz line noise. Convergence occurs in just over two seconds.
DFT of AC Line (60 Hz) Noise 0.6 volts (V)
100 120 140 160 180 200 frequency (Hz) DFT of Canceled AC Line (60 Hz) Noise
0.6 volts (V)
Figure 7: Frequency domain view of pure AC line 60 Hz noise cancellation. The fundamental 60 Hz component is reduced 25 dB.
AC Line Contaminated Action Potential Signal 1 0.5 volts (V) 0 -0.5 -1
0.06 0.08 time (s) Clean Action Potential Signal after ANC
1 0.5 volts (V) 0 -0.5 -1
0.04 time (s)
Figure 8: Action potential test demonstrating the results of a simulated neurobiology laboratory experiment. Top shows contaminated signal and bottom the clean signal.
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Rest Day. We started the day around 8:30 a.m. with a great breakfast at a family owned restaurant. I really like these because you get a feel for the area. 5 of us went there so we could helped their bottom line.
Then it was off to the bike shop, that was to open at 10 a.m. according to their website, but when we arrived at 9:45 a.m. we saw a sign on the door that said they didn't open until noon. Then the question was do we ride another 4 ½ miles, one way, to another bike shop or wait. We chose the ride.
The ride took us down Government road which was not a good road and had heavy traffic. At one stop light we had a car make a right hand turn right in front of our first biker barely missing him. Then further down the road there was construction so the heavy traffic narrowed from 2 lanes to 1 lane. This made for some difficult riding, fortunately we only had to stay on it for a 1/2mile before turning.
From then on it was clear sailing to the second bike shop. When we reached the store they welcomed us and had us bring in our bikes and offered us water. Great start.
One rider had to have his lower bracket repaired. The mechanic put his bike on the rack immediately and went to work. When the bike shops heard what we are doing, they did everything they could to get our bikes back in working order quickly and in many cases at a discount.
I of course had my own mission, find a new helmet. They had a good selection but only one my size and it was the one on the display, which was not a problem. Of course as with all bikers you can't go into a bike shop and only buy one thing so I picked up a new front light since the ones I had would quit in mid afternoon each day. Now I can have light all day. When I went to check out they gave me a 15% discount also. I was impressed.
After shopping, we returned to the church to store our purchases before venturing out to explore the down town and river front areas.
The Mississippi river area was interesting. They have the USS Kidd which is a Fletcher class destroyer and is permanently docked. They also have a museum on shore for the USS Kidd also.
While riding on the dike, we stopped and talked to a couple that were lived in Baton Rouge to find a good place to eat. Without hesitation they pointed us to Florida street which is where Po'boy Lloyd's is located. They suggested the sea food Po'boy and the bread pudding. As soon as the words came out of our mouths they said they were all sold out of bread pudding. From what we understood if you want bread pudding you need to be there early. I had a fried oyster and crawfish po'boy and a cup of gumbo, of which both were very good.
Then back to the church for a little rest and relaxation.
Great choice in place to eat! Being a native from Baton Rouge, I try to eat there at least every other time I get to the city. No visit to the capitol to see the bullet holes where Huey Long was shot or to try your luck at the casino?
Be safe as you continue your journey.
Baton Rouge, does have good eating places. My older sister & Husband lived there until 2016, when she passed away@ 92, My niece moved her Dad to Tx, a month later, He was retired Dr.
Ed Chubbuck of engineering @ LSU., College St.@ Perkins was where they were living @.Sunshine Village, I've been over there many times since he stared teaching in 1956 ?


This record was published by Natural England on 27 October 2004 .
The Phoenix House and English Nature partnership existed to help substance misusers challenge themselves as individuals to build self-esteem, self-confidence and motivation through the power of activity in wildlife-rich environments. This report sets out the theoretical basis for an eco-based therapy treatment programme, and the first hand experiences of participants. There is an on-going evaluation programme in place to quantify the added value that such a programme can bring to the therapeutic process. The experiences reported here show that there are very real long term benefits for the individual.