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In the Information Technology world, cloud computing technology offering unlimited amount of IT resources and services to end users over the internet on pay-per-use basis. End users are accessing the cloud services on their mobile or personal computers. Service providers are upgrading their services very frequently to enhance the services, and to use their upgraded services, end users are also required to update the specification of their devices. But it will be very costly for the end users to upgrade their devices for high specification to use the enhanced services. Desktop Virtualization is an extensive technology of cloud services. It is the new concept, in which users can access the virtual desktop of required specifications, software and operating system on their old devices anytime and anywhere. With the help of desktop virtualization, users will be benefited by avoiding the cost of frequent upgradation of mobile or personal computer system. Desktop virtualization technology is proving to be a boon for large and small organizations who have to upgrade their computer system with new technology, which is a very costly and challenging process. Desktop virtualization avoids upgrading the hardware of the client machine repeatedly. It allows us to access all applications and data at a low cost on our old machine. This paper presents the comparative analysis of various approaches for desktop virtualization and various challenges which required the solution. Analysis presented in paper has been done based on various performance parameters which will provide the end users low-cost cloud services and best performance on their mobile or personal computers.

To validate a certificate, a user needs to install the certificate of the root certification authority (CA) and download the certificate revocation information (CRI). Although operating systems and browsers manage the certificate trust list (CTL) of publicly-trusted root CAs for global users, locally-trusted root CAs still play an important role and it is difficult for a user to manage its CTL properly by itself. Meanwhile, the CRI access is inefficient, sometimes even unavailable, and causes privacy leakage. We revisit these problems by analyzing the TLS sessions within an organization. To the best of our knowledge, we are the first to analyze CTL management and CRI access on the scale of medium-sized organizations. Based on the analysis, a locally-centralized design is proposed to manage the CTLs of all users by IT administrators and access the CRI services for all users, within an organization. We apply this design to desktop virtualization systems to demonstrate its applicability, and build vCertGuard with oVirt and KVM-QEMU. In vCertGuard, the CTLs of all virtual machines (VMs) are managed in the VM monitors (VMMs). In the CTL, the self-signed certificates of publicly-trusted root CAs are properly configured, while each locally-trusted certificate chain is specified one by one. vCertGuard accesses the CRI services for all VMs, and the downloaded CRI is cached and shared among VMs. Because most TLS servers are visited by multiple users of an organization, it reduces the cost of CRI access. Experimental results of the prototype system show that vCertGuard maintains the CTLs with a negligible overhead, and significantly improves the performance of CRI access.

Smart mobile devices have significantly increased the popularity of Bring-Your-Own-Device (BYOD) at work, as they benefit people's daily lives. However, BYOD comes with several challenging issues such as limited hardware capacity, frequent upgrades of applications, and security and privacy concerns. Virtual Mobile Infrastructure (VMI), a general framework that provides more reliable and secure solution for BYOD, has therefore been proposed. The key of VMI is to host a mobile Operating System (OS) on a remote cloud data center, and run mobile applications on it. However, VMI faces performance challenge as it needs to display the entire virtualized desktop on a mobile device while the real content of the desktop is on a remote server. To address the performance challenge, we design and implement a VMI named vMobiDesk on top of Android with optimized network transfer mechanisms and display virtualization. In particular, vMobiDesk focuses on virtualizing the display of Android desktops, redirecting users' input events, providing audio support and remote camera. The experimental results show that vMobiDesk has low virtualization overhead, as well as enables mobile users to obtain good experiences with BYOD applications.

This paper introduces a renewed gateway to ENEAGRID distributed computing resources named Fast Access to Remote Objects 2.0 (FARO 2.0). FARO 2.0 is a tool for application and desktop virtualization with a focus towards user experience (UX), providing trained as well as untrained users with a collection of centralized services that can be seamlessly used on their client through a remote desktop protocol. FARO 2.0 is a JavaFX application whose graphical user interface (GUI) and whose main logics have been implemented through the well-known Web technologies (HTML5, CSS3, Javascript) for easier maintainability and customizability, taking full advantage of the WebView component. The FARO 2.0 framework has been deployed both as a general purpose GUI for remote user access to ENEAGRID resources and as a specialized application or workflow-oriented GUI. They are applied in a set of applicative domains, ranging from materials science to technologies for energy and industry, environmental modeling, and nuclear fusion. Some examples and results are also presented.

Demand for remote work has surged as the COVID-19 epidemic has spread around the world. As one of the main implementations of desktop virtualization, Virtual Desktop Infrastructure (VDI) is popular and widely used in corporate remote work. A VDI user can connect to and use a virtual machine in a remote data center by logging in with a username and password using any device anywhere with Internet access. VDI has mobile convenience but is at risk of password leakage and insider threat. Traditional authentication methods, such as password and PIN, cannot withstand these threats. This work presents a keystroke-based continuous user authentication based on the Bidirectional Long Short-Term Memory (Bi-LSTM) network and embedding mechanism in deep learning to defend against such risks. It verifies the current user's identity based on the user's typing behavior continuously and non-invasively. We implement it on SPICE VDI and evaluate its performance and deployment feasibility on a public keystroke dataset - the Clarkson II dataset, which collected in uncontrolled and natural settings. The results show that it achieves state-of-art performance. It detects intruders with 8.28% of EER when only using 30 keystrokes and 0.85% of EER when using 990 keystrokes.

VMware Workstation Pro is one of the most popular end-user desktop virtualization solutions used by enterprise IT personnel. It allows IT engineers to build and test real-world-like virtual machines and network devices from their own PC/laptop. Learning to build a fully functioning and integrated virtual lab on a single computer and master Python network automation basics on a single PC is this book’s underlying goal. This chapter is designed to teach you the basics of the most popular and versatile VMware product, VMware Workstation 15 Pro, and basic virtualization concepts. After reading this chapter, you will gain the following knowledge: you’ll understand the difference between Type-1 and Type-2 hypervisors, understand various IT vendors offering different desktop virtualization solutions, learn how to install VMware Workstation, learn how to perform general administration on VMware Workstation, and understand how VMware Workstation’s network adapters operate.

Distributed computer network system is a network system with high cohesion, transparency and autonomy. Users of a distributed system see a single, high-performance and high-reliability data computing and processing system with a large number of resources. With the long-term development of virtualization technology, the performance of virtual machine can meet many application requirements, especially for the virtualization of processor and memory, which has reached the performance similar to that of physical host. With the popularity of desktop virtualization technology, many enterprises begin to deploy desktop virtualization system. Nowadays, the virtual machine with certain characteristics and performance advantages has gradually matured after a long time of development, and has been widely used in computer related industries. Based on the connotation and characteristics of virtual machine, this paper analyzes and studies the design and implementation process of operating system in distributed computer system.

Virtualization technology is rapidly spreading to all IT fields. For different application scenarios, server-based computing has different advantages. Cloud computing is a hot research topic at home and abroad recently. Software and hardware resources are shared through virtualization technology, and then provided to corresponding cloud computing services according to user needs. This paper mainly studies a mobile Internet desktop delivery method and system based on virtualization infrastructure. It consists of VDI system, diskless workstation system and unified storage system. In this scheme, by modifying the virtual graphics driver of desktop cloud server, the video player starts GPU video acceleration by default to process HD video, and at the same time, the original stream of undecoded HD video and processing instructions are sent to the client for decoding and rendering in real time in the virtual graphics driver layer. It provides a reference for future large-scale construction of desktop cloud system, comprehensive replacement of traditional PC, reduction of operation and management costs, and improvement of enterprise information security.

Virtual Desktop Infrastructure (VDI) is a Virtualized Technology that hosts the user’s desktop at Datacenter Server. OpenStack is the most successful opensource enterprise cloud platform. Cloud-based VDI, also known as “Desktop as a Service” or DaaS, increases utilization of Datacenter infrastructure, provides high elasticity, increases service diversity, and improves scalability. It also allows for prioritizing delivering value, give the choices to use a wide range of hypervisor/storage/network. In this paper, an architecture proposed that comprises three major components that are, hypervisor, connection broker, and display protocol for enterprise-level VDI on OpenStack. The hypervisor used to host many virtual machines on a single hardware. Connection broker used for configuring, inventorying, provisioning, and centralized management of desktops and display protocol allows users to view the desktop that hosted at Datacenter. Lightweight Directory Access Protocol (LDAP) used for user authentication and authorization for desktops. In the paper, we explore the architecture design and implementation of the VDI system on OpenStack and verifies the experiment results.

Mail user agent (MUA) programs provide an integrated interface for email services. Many MUAs support email encryption functionality to ensure the confidentiality of emails. In practice, they encrypt the content of an email using email encryption standards such as OpenPGP or S/MIME, mostly implemented using GnuPG. Despite their widespread deployment, there has been insufficient research on their software structure and the security dependencies among the software components of MUA programs. In order to understand the security implications of the structures and analyze any possible vulnerabilities of MUA programs, we investigated a number of MUAs that support email encryption. As a result, we found severe vulnerabilities in a number of MUAs that allow cache side-channel attacks in virtualized desktop environments. Our analysis reveals that the root cause originates from the lack of verification and control over the third-party cryptographic libraries that they adopt. In order to demonstrate this, we implemented a cache side-channel attack on RSA in GnuPG and then conducted an evaluation of the vulnerability of 13 MUAs that support email encryption in Ubuntu 14.04, 16.04 and 18.04. Based on our experiment, we found that 10 of these MUA programs (representing approximately 77% of existing MUA programs) allow the installation of a vulnerable version of GnuPG, even when the latest version of GnuPG, which is secure against most cache side-channel attacks, is in use. In order to substantiate the importance of the vulnerability we discovered, we conducted a FLUSH+RELOAD attack on these MUA programs and demonstrated that the attack restored 92% of the bits of the 2048-bit RSA private key when the recipients read a single encrypted email.

As a solution for cloud computing, desktop virtualization realizes the remote execution of applications and feeds back execution results in the form of ”screen updates” through network, aiming to offer users the same experience as operating in local systems. It is challenging to achieve this goal since timeliness and reliability should be both guaranteed during the process of screen updates transmission, but the two requirements tend to be difficult to be satisfied simultaneously. Reliable transmission will induce more latency to perform reliable mechanisms, which can influence the timely delivery of screen updates. Timely transmission just provides a best-effort data delivery service, failing to react well to unfavorable network conditions. In order to cope with this problem, we propose a Partially Reliable Transmission Scheme (PRTS) for screen updates transmission in desktop virtualization environment. It tries to make trade-offs between timeliness and reliability and employs a QoE-perceived model to sense the visual quality experienced by users. Distinguished with existing transmission schemes, PRTS adjusts its sending strategy not only according to current network conditions, but also according to users’ QoE. The experimental results show that PRTS can improve the transmission efficiency of screen updates and also the visual quality in desktop virtualization environment under different network conditions.

Aiming at many problems of school multimedia classroom management, a remote control system for multimedia classroom based on cloud computing is developed. The system includes cloud computing management platform, network switch, single-chip microcomputer and equipment in the multimedia classrooms. It uses VMware desktop virtualization technology to deploy virtual machine templates of different courses in each classroom through the campus network. It controls all multimedia equipment in each classroom by single-chip microcomputer remote control. In terms of software and hardware, key problems such as multithreading, socket communication and remote control are solved and a single-chip microcomputer is developed to control the classroom equipment through the serial ports automatically. Compared with the traditional system, the system based on cloud computing has the advantages of rapid deployment and unified management. It improves the teaching effects of multimedia course and it reduces the construction and maintenance of multimedia classrooms.

Academic organizations are supposed to seek certain balance between the concerns of security, stability and availability of shared computer labs to achieve the course learning objectives. Some academic activities in computer science courses require students to control and configure some laboratory devices. Students in advanced courses may use some risky applications for some learning activities. It may affect the stability, availability and security of the working nature in the shared lab and networks. Virtualization Platform has the ability to overcome these concerns to achieve learning objectives. Virtualization technologies allow students to access and control the computer settings as well as the working environment in advanced applications without affecting the operational availability of computer labs throughout the college day. Virtualization enables computer security teachers to train their students on many hands-on activities without exposing or causing damages to computer labs. This paper presents the usage of virtualization technology in such environment, the opportunities and benefits of using this technology in computer security oriented courses. The paper also discusses the use of the VMware workstation pro as a sandbox for risky lab activities in computer security courses. Here the Desktop Virtualization offers great opportunities to teach advanced skills in computer security courses. Also, this paper outlines the challenges and limitations of virtualization along with some recommendations to address these limitations.

In view of the shortcomings of the traditional manual means of GPS field mapping data in the earthquake field, the data quality management is inefficient. This paper develops the GPS original platform based on the desktop virtual observation data management, reporting, quality management and archiving. Based on the research content of this paper, a set of seismic field data management system software based on desktop virtualization platform was designed and developed to solve the inconvenience caused by the complex operation process of GPS data service. The results in this paper will effectively improve the efficiency of GPS measurement data management and quality inspection.

In this paper, a virtual desktop cloud system based on OpenStack architecture is proposed to specifically satisfy the requirements for teachers and students in experiment classes. We design control and management components for the virtual desktop system, especially considering the schedule management algorithm. Based on OpenStack cloud platform, we implement the architecture of server for integrating the superiority of OpenStack into desktop Virtualization System.

Virtualization technologies introduce additional uncertainty and overhead for distributed applications, that may challenge their timeliness. The additional software abstraction layers of the virtualization software offer powerful parallel execution environments but, at the same time, reduce the effective performance as additional software layers are introduced. This requires some fine tuning of, among others, the communication middleware software. The different resource management mechanisms of the middleware may collide with the specific algorithms replicated by the underlying virtualization software. The present work characterises the set of steps of a publish-subscribe communication middleware in a distributed system, enhancing it to suit the communication scheme of virtualized remote nodes. The potential communication steps are identified, and the overhead introduced by the execution over the virtualization software is provided by means of a data communication rate metric; a set of benchmark tests are presented that empirically evaluate the overhead and stability of the most widely used publish-subscribe (P/S) middleware named DDS (Data Distribution System for real-time systems). A general purpose cloud computing virtual machine monitor is utilized to identify the side effects and the drawbacks of the general virtualization technology. Results are obtained on a setting with two different DDS implementations over a general purpose virtualization software, together with a discussion about the potential drawbacks of the main communication operations.

This special issue aims to present recent technical advances in screen content video coding and applications. Screen content video has recently evolved from a niche to the mainstream due to the rapid advances in mobile and cloud technologies. Real-time, low-latency transport of screen visuals between devices in the form of screen content video is becoming prevalent in many applications, e.g., wireless displays, screen mirroring, display interfaces, screen/desktop virtualization and cloud-based mobile virtual reality. Today’s commonly-used video coding methods, however, have been developed primarily with camera-captured content in mind. These new applications create an urgent need for efficient coding of screen content video, especially as the support of 4k or even 8k resolution begins to achieve mass market appeal.

Desktop virtualization, which is to make the desktop virtual so that users can access any application through the network with any devices at any time and any place, is being widely used now as an emerging trend. However, it is important to further improve this approach while maintaining good user experience. Though the simple protocol for independent computing environments as a virtual desktop solution can achieve a user experience similar to an interaction with a local machine, there are still many deficiencies in it. For instance, it cannot apply to environment of high controllability of user, and the quality of graphic interactive experience is to be improved. In this paper, to meet QoE requirements of user, we build a feasible file transfer and sharing mechanism and propose a graphics subsystem optimization strategy based on simple protocol for independent computing environments SPICE, namely Transparent Desktop. We also verify that the Transparent Desktop can provide users with ubiquitous desktop services of higher efficiency, stronger user-controllability and better QoE through the experimental. Copyright © 2016 John Wiley & Sons, Ltd.

Current SCADA infrastructure that supported hydro automation and control system at PT Vale Indonesia is obsolete. That condition puts the overall operation of power generations in a risk due to obsolete hardware and operating system (OS) infrastructure. The server hardware has no spare part available in the market that can lead SCADA and control system break down at any time. The obsolete OS has no longer receive security update that can lead virus and security breach onto the automation network, therefore SCADA infrastructure upgrade is mandatory to be done to support operation of hydropower generations. Other problems of current automation infrastructure are operating cost, it is due to numerous servers and PCs (personal computers) that installed to serve the automation and control system. Most of these servers and PCs consume a significant amount of electrical power and also the energy of a cooling system, while the utilization ratio of those type of equipment is very low, around 5% to 10 % only [1]. They also - mainly a server - require significant yearly maintenance cost. To overcome the above problems, servers and desktop virtualization technology are studied in this paper as an option for the requirement of SCADA infrastructure upgrade. The technology offering an opportunity to consolidate multiple under-utilized servers and PCs of SCADA control system into a few physical servers and thin client, thereby reducing the energy requirements for the power infrastructure, cooling system, maintenance budget and capital cost of the necessary upgrade. The result of virtual technology implementation reduces 64.80% of upgrade capital cost for material and installation, 40.65% less energy requirements for the infrastructure cooling system, saving 62.20% electrical energy for the entire infrastructure SCADA control system and also reduce 92.43% of yearly maintenance cost.

Storage performance was main challenging factor of user experience that define the success factor of desktop virtualization initiative. Some solution was introduced to cope with primary storage requirement for performance, but most of it were require significant investment and introduce some complexity. Consumer-grade SATA SSD on the other hand were getting lower in price and more reliable, this paper intended to analyze how consumer-grade SATA SSD can be used as a primary storage solution for desktop virtualization in small-scale environment, with computer laboratory in University ABC as initial case study to deploy the scenario in production environment. To observe how the consumer-grade SATA SSD can perform, this paper conducted 3 categories of scenario: HDD-SAS 7.2k, SSD-SAS and SATA-SSD, using RAID10 and HBA (JBOD) mode configuration. Experimental test conducted within the scope of this paper showed that consumer-grade SSD-SATA can be used as a primary storage for small-scale desktop virtualization solution. While the price of SSD-SATA within the case of this paper was only about 10,4% higher when compared with HDD-SAS 7.2k solution, SSD-SATA (RAID10) also had significant performance improvement when compared with HDD-SAS 7.2k (RAID10), about 19,67 times higher in bandwidth and IO; and only 0,049 times in latency (95,07% lower latency time). While in HBA-mode, SSD-SATA also gave significant improvement compared with HDD-SAS 7.2k (RAID10), about 18,03 times bigger for bandwidth; and about 0,055 times for latency time (94,45% lower latency time).

Deduplication in storage allows us to eliminate duplication in order to maximize the usage of storage capacity. The majority use of deduplication was for backup functions, but also applicable for primary storage. One of good candidate for deduplication implementation is desktop virtualization. Deduplication is resource intensive, so its application to the primary-storage can have serious implications on overall system performance that negatively impact user experience. This paper attempts to perform performance evaluation by applying deduplication (post-dedupe approach) to the primary storage, the implementation is done by creating NFS-based virtual storage (vstorage) using Windows Server 2016. The use of vstorage itself has a significant impact on storage performance, the number of IOs and bandwidth reduced to 13.33 times when compared to the basic performance of storage without vstorage. Under these conditions, it is strongly recommended to use caching mechanisms, in the context of this paper, the author used RAM as a red-and-write cache. The use of cache proven to improve performance, even faster than basic storage performance up to 1.74 times. Furthermore, the author also performed performance test while the dedupe run, causing decrease in performance up to 4.84 times compared to the performance when the dedupe process is not running. The use of Windows Server 2016 as a deduplication solution overcomes storage capacity limitations, and the use of RAM as a red-and-write cache becomes the solution for storage performance. Furthermore, the author creates 2 vstorages on an existing server that has 35 VMs, where the average number of IOs per VM is 401.94 IOs for vstorage #1 (13 VMs) and 378.24 IOs for vstorage #2 (12 VMs). The author also tested this configuration for 4 months and got positive feedback from 93,33% (14 of 15) of the respondents.

With the development of virtualization technology, desktop virtualization is becoming more and more mature. Desktop virtualization can effectively isolate the use of users and the management of the system, but in the access to virtual desktops, its security has become a key factor which can't be ignored. In this paper, we propose a set of technologies that enhance the security of virtual desktops and can effectively secure virtual desktops from multiple levels. We improve the spice protocol and implement the multi-level access mechanism of users and virtual desktops. The Docker technology is used to implement the isolation of the communication, storage and network between the virtual desktop processes. Based on the X server mechanism, we isolate the virtual desktop client from GUI Level. The experimental results have shown the effects from various aspects, as well as differences in performance with the original client.

It is possible for virtualization of desktop to dramatically reduce maintenance costs and improve the security using various virtualization techniques rather than previous desktop environments. Also, with blocking beforehand the information leakage caused by data centralization, it is easy to manage the information security. This desktop virtualization provides creation and duplication of data and standardized desktop environments using easy and fast virtualization works. So, it is possible to improve efficiency, stability, and fusibility of virtualization. In this paper, with the desktop virtualization, the power saving effects are obtained from 65,750(kW) to 7,300(kW) , which is from 480(w) to 50 (w) for using one desktop for 8 hours per a day. In addition, the 62 desktops and 62 monitors are combined to one operational server with 62 thin clients. As a result of this, the security is improved greatly by data centralization, which the user can access the main server as a thin client with given space.

Modern offices are crowded with personal computers. While studies have shown these to be idle most of the time, they remain powered, consuming up to 60% of their peak power. Hardware-based solutions engendered by PC vendors (e.g., low-power states, Wake-on-LAN) have proved unsuccessful because, in spite of user inactivity, these machines often need to remain network active in support of background applications that maintain network presence. Recent proposals have advocated the use of consolidation of idle desktop Virtual Machines (VMs). However, desktop VMs are often large, requiring gigabytes of memory. Consolidating such VMs creates large network transfers lasting in the order of minutes and utilizes server memory inefficiently. When multiple VMs migrate concurrently, networks become congested, and the resulting migration latencies are prohibitive. We present partial VM migration, an approach that transparently migrates only the working set of an idle VM. It creates a partial replica of the desktop VM on the consolidation server by copying only VM metadata, and it transfers pages to the server on-demand, as the VM accesses them. This approach places desktop PCs in low-power mode when inactive and switches them to running mode when pages are needed by the VM running on the consolidation server. To ensure that desktops save energy, we have developed sleep scheduling and prefetching algorithms, as well as the context-aware selective resume framework, a novel approach to reduce the latency of power mode transition operations in commodity PCs. Jettison, our software prototype of partial VM migration for off-the-shelf PCs, can deliver 44--91% energy savings during idle periods of at least 10 minutes, while providing low migration latencies of about 4 seconds and migrating minimal state that is under an order of magnitude of the VM’s memory footprint.

As the increasing number of applications in Office Mobile, it’s hard for the traditional IT network infrastructure to carry out remote management and maintenance. The Citrix-based Cloud Desktop can manage and maintain users’ terminal equipment, reduce the operation and maintenance costs and fulfils the enterprise’s centralized management. Meanwhile, Cloud Desktop provides users with a personalized desktop and a variety of access methods which improve service levels and business continuity needs. Compared to the traditional IT infrastructure, the Cloud Desktop provides users with faster & higher predictability, higher cost performance and richer applications. Moreover, it is particularly prominent in energy conservation and cost savings.

Virtualization is a technique in which the user required services run remotely in a ubiquitous environment which gives scalable resources. Virtualization is being used in cloud computing for load balancing and aggregation of cloud resources. Virtualization provides higher hardware utilization. It is also being used for partitioning of computational resources and hence supports sharing of resources. Virtualization has different types such as Native virtualization, Full virtualization, Operating system level virtualization and Para virtualization. Other than these there is Resources virtualization, Desktop virtualization, Server virtualization, Data centres virtualization and application virtualization. The resources virtualization is implemented in different forms such as the Full virtualization, Native virtualization, Para virtualization, Operating system (OS) layer virtualization or Hosted virtualization. Virtual machines and Virtual machine monitors (VMMs) have been developed to offer better energy efficient solutions to the virtualization problems. Virtualization tools like OpenVz, Xen, VmWare etc. are widely used in the computing industry.DOI: http://dx.doi.org/njst.v15i2.12131Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 141-150

As the application of desktop virtualization systems (DVSs) continues to gain momentums, the security issue of DVSs becomes increasingly critical and is extensively studied. Unfortunately, the majority of current researches on DVSs only focuses on the virtual machines (VMs) on the servers, and overlooks to a large extent the security issue of the clients. In addition, traditional security techniques are not completely suitable for the DVSs' particularly thin client environment. Towards finding a solution to these problems, we propose a novel behavioral anomaly detection method for DVS clients by creating and using process portraits. Based on the correlations between users, virtualized desktop processes (VDPs), and VMs in DVSs, this proposed method describes the process behaviors of clients by the CPU utilization rates of VMs located on the server, constructs process portraits for VDPs by hidden Markov models and by considering the user profiles, and detects anomalies of VDPs by contrasting VDPs' behaviors against the constructed process portraits. Our experimental results show that the proposed method is effective and successful.

Generally it is not easy for an instructor to prepare and deliver electronic courses via e-learning. Therefore it is necessary to work and develop an easy system. In this context module technology was used to for provide modularity in conducting educational development of e-learning course. Then, rapid e-learning was used for more quick and easy course development. In order to implement modular rapid e-learning, a desktop virtual environment was set up. Modular rapid e-learning was used by teachers and students in a one semester course and student success and reactions were evaluated. And also the overall hybrid system cost was calculated and reported. In implementation we combined modular course design with rapid e-learning and desktop virtualization in education of 3rd year nursing students for a one semester course. The effectiveness of this hybrid method was evaluated with respect to students’ success, students’ opinions and over all cost effectiveness. It was seen that the hybrid method was educationally more effective than traditional method comparing with previous year students' success and fit with students’ requirements. The cost reduction was %41 comparing with traditional desktop and e-learning system.

Cloud based virtualization technology gained popularity coupled with sustained growth of cloud computing. DaaS (Desktop as a Service) is a desktop virtualization technology which enables the most powerful service in the cloud environment. It is used in many areas such as financial services, manufacturing, healthcare, and education. Also, it enables fully personalized desktops for each user by providing all the security and simplicity of centralized management. However, most of the existing DaaS technologies are hypervisor based systems. It has a performance degradation problem to loading each desktop image because of the multilayered architecture by the Guest OS and slow creation time of each VM. In addition, it cannot provide optimized resources to personalized services which have different resource demands, as it allocates static resources for CPU, RAM, and Network bandwidth in each VM. In these problems, the DaaS in cloud cannot offer better user experience than local PC environment. In this paper, a data-driven resource allocation method for the container based DaaS system is proposed to solve problem of conventional hypervisor based DaaS and its static allocation. To propose a novel resource allocation method, we perform comparative analysis and simulation according to resource usage and workload. By doing this, the proposed scheme looks forward to accelerate growth of the DaaS through improving the user experience and the resource efficiency of the datacenter by allocating the fine-grained resource.

Desktop as a Service (DaaS) is a desktop virtualization service hosted in the public or private cloud. Virtual Desktop Infrastructure (VDI) is the key technology that enables virtual desktops. The virtual desktop that runs in a data center is delivered to the end user's device by using Remote Desktop Protocol (RDP). Currently, resource allocation in the VDI has become one of the key issues and big challenges for the organizations which want to migrate from traditional desktop to the virtual desktop. The main objective of resource allocation in the VDI is to provide resources to the virtual desktop without over-provisioning while reducing resource usage and response time. We believe resource usage and response time can be reduced without over-provisioning by selecting an Operating System (OS) in the VDI which has fewer RAM utilization, CPU response time and application response time before calculating virtual desktop density and deploying VDI in a large scale. The aim of this paper is to evaluate OS 1: Windows 8.1 Enterprise 32-bit and OS 2: Windows 10 Enterprise 32-bit as dedicated virtual desktops in the virtual desktop infrastructure by using different workloads to find which operating system has fewer resource usage and response time in terms of memory usage, CPU and application response time. We used experimental design and quantitative approach. The results indicate that OS 1 has the lowest memory usage and CPU response time than OS 2. In addition, results of application response time comparison between OS 1 and OS 2, show that OS 1 has the lower application response time than OS 2 as well.

Teaching network administration for undergraduate students possesses a number of challenges. On one hand, network administration requires a wide spectrum of ad-hoc technologies from service management to physical connection. It is hard to select a critical set of technologies to fit into one course as well as maintain a clear organization and flow among these technologies. On the other hand, the rapid pace of technology advancement in the field of IT requires up-to-date technologies (e.g., Cloud Computing) to be included in a timely manner. In this study, we present our design of an undergraduate network administration course. Different from the literature, the novelties of this design are multi-fold. First, we identify a group of administration tasks, which, for the first time, is presented to the students in a top-down approach according to the Internet protocol stack. Second, given our prior lesson with virtualization, we adopt a hybrid approach that combines both physical and virtual technologies in the lab design (rather than solely resorting to virtualization). Finally, being aware of the implication of desktop virtualization and network virtualization to network administration, we design labs that cover desktop virtualization, and Cloud Computing based on Amazon AWS cloud.

Virtual Desktop Infrastructure refers to a process of running user's desktop in a virtual machine that lives on a server in the datacenter. A protocol is important in the communication process of virtual desktop infrastructure. For small deployment scenario, we have two options: using built-in RDP protocol that comes from Windows desktop; or adding more investment for PCoIP protocol in VMware environment. This paper try to analyze the performance difference between RDP and PCoIP, using PCMark to simulates daily task and applications, and at the same time using network monitoring tools to measure the bandwidth consumption of the tested protocols. The test result shown that there is very slight performance difference between RDP and PCoIP, but the interesting part comes that PCoIP is more advanced for multimedia, it shown superior performance for multimedia playback (no artifacts like on RDP). Beyond its limitation, RDP is still suitable for users that want to deploy small scale of desktop virtualization for light tasks like office productivity (more text, less graphics) may consider RDP as starting deployment protocol.

This work focuses on how to provide the best virtual desktop technology, virtualization performance and hardware in the computer classroom. There are using the three popular virtualization technologies in the same environment to establish the same conditions, pure performance comparison: VMware Horizon, Citrix XenDesktop, and Microsoft VDI. Test software used to the current popular software, system performance including a test CPU and RAM PassMark Performance Test,and observe the vCenter Server performance changes and record statistics, to determine the advantages and disadvantages of various virtualization technologies. Finally, hardware support exclusive GPU virtualization product - Nvidia GRID K2 through GPU virtualization technology sharing and vGPU to carry on VMware vSphere, via Cinebench, YouTube 1080p high-quality video for bandwidth flow test, and use 3DMark Fire Strike Extreme to enhance the performance of virtual desktop, and bring users to enjoy higher-quality cloud services. The results of this study show that virtual desktop technologies are good in different field. On the other hand, the hardware performance breakthrough Moore’s Law of this era, the single CPU has more number of cores, and the memory capacity of the larger single,and provided by the GPU for graphics acceleration processing capabilities, the performance of server has been perfect than the previous. Therefore, the quality of cloud services is also greatly improved. The study shows that the virtual test can be imported into the classroom through the stress test in the experiment. To make sure the its performance and cost are really suitable for classroom imported desktop virtualization system.

VMware, VirtualBox, Virtual PC and other popular desktop virtualization applications are used only by a few users of IT techniques. This article attempts to make a comparison model for choosing the best cloud platform. Many virtualization applications such as VMware (VMware Player), Oracle VirtualBox and Microsoft Virtual PC are free for home users. The main goal of the virtualization software is that it allows users to run multiple operating systems simultaneously on one virtual environment, using one computer desktop.Keywords: Cloud Computing, Virtualization, Jaccard Index, Comparing Model(ProQuest: ... denotes formulae omitted.)1 IntroductionThe desktop virtualization software allows multiple operating systems to install on a computer or laptop in a virtual environment without disturbing the host operating system. Moreover, in many such programs, one can change to another operating system without rebooting the computer. The main advantage of these applications is that they can be used on technically weaker computers, taking advantage of the virtual machine features on the server. [16], [17]The advantages of virtualization platforms are:1) Multiple operating systems can be used at a time, without rebooting.2) They represent a completely isolated medium from the host operating system, because it is a virtual environment. Therefore, the possibility of infection with viruses or other unwanted items while working decreases.3) They allow the running of different applications or different operating systems on one type of computer. For example, if one wishes to run some applications that only work in Win XP on a system that has installed Win 8, one can install a virtual machine on the existing system (with Win 8 installed) that simulates running Win XP.4) The restoration of a virtual machine is very fast. For example, one can open the virtual machine selecting an older configuration. This function is usually called Snapshot. The Snapshot feature is usually used to create tests on the system.Benefits obtained from the use of cloud computing services [15]* Globalization for access to resources - people around the world can access cloud resources using the Internet.* They make savings by increasing the volume or the productivity. Thus, lower costs per unit, project or product obtain.* They allow running Streamline processes, which leads to obtaining a high efficiency by comparing the results obtained to the corresponding time and the people involved.* They increase accessibility. Access can be made from anywhere, anytime.* The monitoring of the proj ects is more effective.* The levels of training of technical staff are lower. It requires fewer persons to configure and maintain hardware and software platforms.* Savings on software licensing. There is no need to purchase expensive software licenses or software.* They reduce the cost of capital. Companies can make great savings on hardware costs or software.* Mobility - Employees with access to the internet can work anywhere. This flexibility positively affects the work-life balance for employees leading to increased labour productivity.* Increasing flexibility. Changes can be made quickly without involving additional costs.* They reduce spending money on technology infrastructure. Some technologies may be used only on demand when needed in certain projects.* Flexibility - quickly meet business demands* Payment for use - cloud services are usually paid only as long as they are used. Because cloud computing is quickly implemented in any company, start-up costs and running costs are minimal.* Increased Collaboration - Cloud computing increases the level of collaboration, while enabling collaborative work* Document Management - Cloud computing keeps all files in a central location and everyone is working on one version of the document. …

This paper proposes the data security technology for the desktop virtualization environment using the separated software execution method. In the virtual environment where allocates separate VMs to the users, there is a benefit that the programs in one guest machine are isolated from the programs running in another guest machine, whereas in the separated execution environment that supports application virtualization, the isolation is not offered and it causes the data security problem because the applications are executed by the one root privilege in the server. To solve this problem, we provides the data security method using the server storage filter, the viewer filter, and the file mapping table in this paper.

Increasingly mature cloud computing technology promotes virtual desktop technology, which can solve many problems existing in traditional computing models. However, virtual desktop solutions introduce the thorny problem of how to deliver a real desktop experience to users, as if they are using it locally, especially when playing video. The SPICE (simple protocol for independent computing environments) virtual desktop solution provides several image compression algorithms to address this problem with the purpose of making virtual desktops as real as possible. Although different compression algorithms can contribute their own abilities to different images to a large extent, switching between them is a big problem that consumes a large amount of resources to detect the different type of image and also causes jitter of the virtual desktop. This paper proposes a new solution, called SPICEx, using the JPEG2000 compression algorithm with dynamic compression ratios to solve the problem and finally validates that the performance is better than that of SPICE. With better quality of user experience and also reducing bandwidth consumption, SPICEx solution is meaningful in virtual desktop fields and can be widely used.

In this paper, the current problems and demands of campus information system was analyzed and the desktop virtualization solutions were probed. Thus, under the cloud system structure, the user can simply login by the client in desktop systems of data center, as well as traditional computer operating. As a result, the flexibility and security in application of resources are enhanced. More over, schools can avoid the repeated investment and reduce the pressure on hardware and software maintenance, and improve the working efficiency.

VOI desktop virtualization technology has realized the new management mode of “centralized management, node operation and maintenance” in the computer room. It has overcome the disadvantages of a large number of management work required by the former protection card mode and the need for high-performance server for VDI desktop virtualization. “Disk network dual standby” technology gives full play to the local performance of the computer, reflecting the excellent local performance and high reliability of the client under centralized management. By integrating virtual machine technology into the VOI image system and relying on the advantages of local computing, a variety of teaching and experimental environments are constructed to completely meet the needs and lay a good foundation for the smooth development of research.

university computer laboratory is an important place to cultivate, exercise the information literacy and to enlighten innovative thinking of university students in the new era. With the continuous development of cloud computing technology, the application of virtualized cloud desktop in university computer laboratory has become an inevitable trend. This text analyzes the disadvantages of traditional desktop deployment mode and the advantages of virtualized cloud desktop based on the construction status of computer rooms in universities, and studies, discusses how to apply desktop virtualization technology to build an experimental teaching environment of virtualized cloud desktop, that is easy to manage, flexible to deploy, resource-sharing and convenient to maintain.

Advancements in cloud computing enable the easy deployment of numerous services. However, the analysis of cloud service access platforms from a client perspective shows that maintaining and managing clients remain a challenge for end users. In this paper, we present the design, implementation, and evaluation of an asymmetric virtual machine monitor (AVMM), which is an asymmetric partitioning-based bare-metal approach that achieves near-native performance while supporting a new out-of-operating system mechanism for value-added services. To achieve these goals, AVMM divides underlying platforms into two asymmetric partitions: a user partition and a service partition. The user partition runs a commodity user OS, which is assigned to most of the underlying resources, maintaining end-user experience. The service partition runs a specialized OS, which consumes only the needed resources for its tasks and provides enhanced features to the user OS. AVMM considerably reduces virtualization overhead through two approaches: 1) Peripheral devices, such as graphics equipment, are assigned to be monopolized by a single user OS. 2) Efficient resource management mechanisms are leveraged to alleviate complicated resource sharing in existing virtualization technologies. We implement a prototype that supports Windows and Linux systems. Experimental results show that AVMM is a feasible and efficient approach to client virtualization.

In this paper, we proposed new virtualization technology that is more convenient and stable in local computing environment, then found technique elements need to desktop virtualization which is based on clients in various virtualization technologies. After running excution of process explorer utility in user level virtualization and VMWare, we found memory capacity that is used 30.1MB in VMWare and 16.6MB in user level virtualization respectively to compare private bytes each of process. We found no significant difference of CPU utilization which is executed application program in local computing environment and user domain with user level virtualization. In this result, proposed vitualization technology is able to minimize performance degradation of local computing envrionment.

In recent years, virtualization computing has become a worldwide reality present in datacenters servers of most organizations. The motivations for the use of this solution are focused primarily on cost reduction and increases in availability, integrity and security of data. Based on these benefits, recently it was started the use of this technology for personal computers as well. That is, for desktops, giving birth to the so-called desktop virtualization. Given the technical advantages of the approach, its growth has been so significant that, before 2014, it is expected to be present in over 90% of organizations. However, this new method is completely based on a physical client-server architecture, which increases the importance of the communication network that makes this technique possible. Therefore, analyzing the network in order to investigate the effects according to the environment implemented becomes crucial. In this study it’s varied the local’s client hardware and the application, i.e., the service used. The purpose was to detail their effects on computer networks in a Quality of Service (QoS) parameter, throughput. Secondarily are outlined perceptions regarding the Quality of Experience (QoE)? This culminated in an assessment that traces the feasibility for applying this technology.

Recently, cloud computing is one of the parts showing the biggest growth in the IT market and is expected to continue to grow into. Especially, many companies are adopting virtual desktop infrastructure as private cloud computing to achieve in saving the cost and enhancing the efficiency of the servers. However, current digital forensic investigation methodology of cloud computing is not systematized scientifically and technically. To do this, depending on the type of each cloud computing services, digital evidence collection system for the legal enforcement should be established. In this paper, we focus on virtual desktop infrastructure as private cloud computing and introduce the most widely used around the world desktop virtualization solutions of VMware, Citrix, and Microsoft. And We propose digital forensic investigation methodology for private cloud computing that is constructed by these solutions.

Cloud computing has recently become a significant technology trend in the IT field. Among the related technologies, desktop virtualization has been applied to various commercial applications since it provides many advantages, such as lower maintenance and operation costs and higher utilization. However, the existing solutions offer a very limited performance for 3D graphics applications. Therefore, we propose a novel method in which rendering commands are not executed at the host server but rather are delivered to the client through the network and are executed by the client’s graphics device. This method prominently reduces server overhead and makes it possible to provide a stable service at low cost. The results of various experiments prove that the proposed method outperforms all existing solutions.

Desktop virtualization is a general solution for providing users with various working environments on a single physical machine. It is typically based on the virtual machine (VM) technology, which can provide smart sharing policies on the scarce hardware. Compared with native computing environments, however, VM may sacrifice the performance, especially in the I/O subsystem. Although certain methods have been proposed to improve the performance of networking and graphic processing, the performance of disk I/O is almost ignored. In this paper, we propose two methods to reduce the extra overhead on Xen hypervisor at different layers of its disk protocol stack. The experimental results show that on the average 21% of unnecessary CPU cycles can be saved from the Xen hypervisor, and when a high performance disk device is applied in the system, our proposed optimization techniques can improve the overall disk I/O performance by 15.6%-36.6% for all benchmarks used in the experiments. Finally, by evaluating our methods in a practical system of desktop virtualization, user-applications can achieve an improvement of 15.9%-23.7% over the original Xen hypervisor.