You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Virtual Learning Environments-A Survey 
Chapter Title:  INTRODUCTION 
1. Abstract of Cited Paper (BIB001):  Abstract This paper introduces Gridcole, a new system that can be easily tailored by educators in order to support the realization of scripted collaborative learning situations. To do so, educators can provide a script specifying the sequence of activities to be performed by learners as well as the tools and documents required to support them. Gridcole can then search for these tools in a service-oriented grid in order to integrate them so that they are available for users during the realization of the situation. Significantly, Gridcole has two features that are not supported by other tailorable systems. First, it allows the integration of tools that use supercomputing capabilities or specific hardware resources, thus enabling the possibility of supporting many situations in which this type of tools is required. Besides, Gridcole can guide learners during the realization of collaborative learning situations according to the sequences of activities specified in the scripts. This way, learners can benefit from the advantages of scripted collaborative learning. Gridcole has been evaluated using three collaborative learning situations conceived for real courses at university level. The results of the evaluation show that Gridcole does provide the desired properties concerning tool integration and activity guidance as well as that the proposed system can provide adequate support for a wide range of collaborative learning situations. 
2. Abstract of Cited Paper (BIB002):  Nowadays, we are witnesses of a transformation in the e-learning arena. This transformation has different drivers involving all the actors in the learning value chain, from final users to learning institutions through technology providers. All those actors share a common goal: making the learning processes more effective through the information and communication technologies. This is happening through the promotion of a paradigm shift from content-centered to process-centered solutions. In this paper, we present the results from the European Learning Grid Infrastructure project concerning models, processes, and services supported by a service-oriented software architecture for creating dynamic and adaptive virtual organizations for learning using Grid technologies. 
3. Abstract of Cited Paper (BIB003):  This paper outlines the adaptation of a course on the management of network services in operating systems, called NetServicesOS, to the context of the new European Higher Education Area (EHEA). NetServicesOS is a mandatory course in one of the official graduate programs in the Faculty of Computer Science at the Universidad Nacional de Educacion a Distancia (UNED), Madrid, Spain, the Spanish University for Distance Education. Since UNED is a distance university, this course is taught entirely online. The adaptation process includes the implementation of continuous assessment, a key feature in EHEA's methodology. This learning-teaching methodology is driven by a set of student activities that implement the continuous assessment. For this, a virtual machine-based framework was defined, and an automatic evaluation system implemented. The evaluation system can handle the large student numbers characteristic of distance learning. If the set of proposed activities had to be performed in person on site, significant resources would have been necessary since many computer laboratories would have been required to accommodate all the students. Furthermore, the proposed framework ensures that students can perform the practical work simply and flexibly, without the need for large computing platforms. 
4. Abstract of Cited Paper (BIB004):  Multi-User Virtual Environments (MUVEs) are often used to support learning in formal and informal educational contexts. A technology-based educational experience consists of several elements: content, syllabus, roles, sequence of activities, assignments, assessment procedures, etc. that must be aligned with the affordances of the technologies to be used. The design process, therefore, has to follow a dual track: the design of the educational experience as a whole and the design of the MUVE. Each design process has some degree of independence, while, at the same time, the two design processes are also deeply intertwined. The paper proposes a novel approach to design (both for the educational experience and the MUVE): a “biological lifecycle” design, where evolution (for survival and fitness) is crucial, while anticipating all the requirements (creating an engineering blueprint) is very challenging. This paper is based upon a number of large-scale case studies, involving nearly 9,000 high-school students from 18 countries in Europe, Israel, and the United States. Substantial educational benefits were achieved by these learning experiences, at the center of which were MUVEs. It cannot be claimed that MUVEs were the only factors for generating these benefits, but for sure they were exceptionally important components.

Literature Review:
In order to understand working of Virtual Learning Systems, it is necessary to define the concept of Virtual Learning. The term 'virtual learning environment' (VLE) refers to the components in which learners and tutors participate in online interactions of several kinds, comprising online learning. E-learning refers to the use of electronic media and information and communication technologies (ICT) in education. E-learning is widely enclosure of all kinds of educational technology in learning and teaching. E-learning is enclosure of, and is widely synonymous with technology-enhanced learning (TEL), computer-based training (CBT), multimedia learning,computer-assisted instruction, computer-based instruction (CBI) or internetbased training (IBT), web-based training (WBT), online education, computer-aided instruction (CAI), virtual education, m-learning, virtual learning environments (VLE) (which are also called learning platforms), and digital educational collaboration. These other alternative names dwell on a specific component, aspect or delivery method. A Virtual Learning Environment (VLE) is a system for transfering learning materials to students by means of the web. These systems constitute student tracking, communication tools, assessment and collaboration. They can be accessed both on and off-campus, which means that they can encourage students' learning outside lecture hall 24 hours a day, seven days a week. This facilitates institutions to teach not only traditional full-time students but also those who cannot regularly visit the campus due to geographic or time restrictions, i.e. those doing evening classes, on distance learning courses, or workers studying part-time BIB004 . There are various kinds of VLE, which all operate slightly varingly but eventually accomplish the identical function and can transfer the same learning materials. A Higher Education academy is probable to have a licence for a VLE that belong to any one of the following three classifications  Off-the-shelf, such as Blackboard or WebCT  Open source (often free to use and adapt whereas support is charged), for instance Moodle  Bespoke (developed by institutions for their own individual needs) There are some international standards associated with VLEs which help to make content and assessments interoperable (i.e. they can be used in different types of VLE). The standard for content is called 'Sharable Content Object Reference Model' (SCORM) and the standard for assessments is called 'Question and Test Interoperability' (QTI) BIB004 . Typically, VLEs provide facilities for managing the learning experience, communicating the intended learning experience and facilitating tutors' and learners' involvement in that experience. The learning experience needs to be communicated via syllabi, complete course content or copies of visual aids/handouts, plus additional resources, links to resources in libraries and on the Internet. Easy authoring tools or standard office software used for authoring should be available to aid this. The learning experience is facilitated typically via self-assessment quizzes and communications tools such as e-mail, threaded discussions and chat rooms. To allow all of this, the systems should provide differential access rights for instructors and students (roles). All the various functions and resources need to be capable of being hyperlinked together within a consistent interface BIB003 BIB005 . From the earliest Internet-based learning systems, people started exploring the possibilities of the worldwide web as a means of supporting learning. The earliest systems which satisfied the 'consensus view' of VLE elements began to appear and included systems such as WebCT and Lotus LearningSpace. During this period, systems were developed which took a pedagogically focused view of e-learning. Several notable examples developed in the UK included Boddington (developed at Leeds University), Colloquia (developed at Bangor University) and COSE (developed by a team at Staffordshire University, of which I was leader). Systems like these were largely constructivist in their approaches, were learner-centric and used novel interfaces BIB001 BIB002 . As things developed, along with the exponential uptake of the use of the web, it became clear that systems which had interfaces which looked like websites and were delivered via browsers were becoming the most successful. Interestingly, research conducted in 2004 showed that 'ease of use' -especially by teaching staff -was the prime consideration in VLE selection. Respondents made great play of the need for an 'intuitive' interface. The 'early adopter' of VLEs largely cited reasons such as learner centeredness, pedagogic change, diversification, and coping with large numbers as reasons for getting involved. By the time of the survey conducted in 2003, leading reasons for selection were ease of use, cost, flexibility and, interestingly, level of use by other institutions BIB002 . By the time of the first JISC/UCISA 'MLE Landscape' survey in 2005, the vast majority of institutions that responded were using a VLE and cited the drivers as:  Enhancing access to learning for students off campus  Broadening participation/inclusiveness  Upgrading the nature of teaching and learning  Utilizing technology to deliver e-learning  Student expectations  Reforming access for part-time student. II. .