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Recently, as Virtual Desktop Infrastructure(VDI) is widely used not only in office work environments but also in workloads that use high-spec multi-core-based applications, the requirements for real-time and stability of VDI are increasing. Accordingly, the display protocol used for remote access in VDI and performance optimization of virtual machines have also become more important. In this paper, we propose two ways to configure desktop virtualization for multi-core-based application operation. First, we propose a codec configuration of a display protocol with optimal performance in a high load situation due to multi-processing. Second, we propose a virtual CPU scheduling optimization method to reduce scheduling delay in case of CPU contention between virtual machines. As a result of the test, it was confirmed that the H.264 codec of Blast Extreme showed the best and stable frame, and the scheduling performance of the virtual CPU was improved through scheduling optimization. [ABSTRACT FROM AUTHOR]

New challenges in the dynamically changing business environment require companies to experience digital transformation and more effective use of Big Data generated in their expanding online business activities. A possible solution for solving real business problems concerning Big Data resources is proposed in this paper. The defined Agile Elastic Desktop Corporate Architecture for Big Data is based on virtualizing the unused desktop resources and organizing them in order to serve the needs of Big Data processing, thus saving resources needed for additional infrastructure in an organization. The specific corporate business needs are analyzed within the developed R&D environment and, based on that, the unused desktop resources are customized and configured into required Big Data tools. The R&D environment of the proposed Agile Elastic Desktop Corporate Architecture for Big Data could be implemented on the available unused resources of hundreds desktops.

NComputing Technology is becoming increasingly important and is being used both in academe and business industry because of its capability of saving energy and maintenance costs. However, the adoption of this technology faces with concerns particularly in end users experiences. The paper aimed to examine the collection of some of the issues and challenges facing the NComputing technology adoption in academe particularly in Surigao del Sur State University and offered an initial roadmap to view the challenges and problems for further research. Findings revealed that most of the students were not satisfied with the performance of this technology. But, for technical support, they found it easy to maintain and troubleshoot.

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. [ABSTRACT FROM AUTHOR]

Teknolojinin insan hayatındaki yeri her geçen gün geliştirilen yeniliklerle artarak devam etmektedir. İnsanlar her an,m her yerde masaüstü kaynaklarına erişerek ihtiyaç duyduğu işleri gerçekleştirilebilir. İnterneti olan dizüstü bilgisayar, tablet gibi herhangi bir istemciden kaynağa erişerek masaüstü sanallaştırma sistemini kullanabilir. Yüzlerce, binlerce istemcinin olduğu bir veri merkezindeki ağ cihazlarının trafiğinin yükü oldukça fazla olacaktır. Ayrıca istemcilerin hücresel ağ kullanarak bağlantı sağladıklarında da veri trafiği kendilerine maliyet oluşturacaktır. Bu çalışmada, masaüstü sanallaştırma teknolojilerinde kullanılan PCOIP, Blast Extreme ve RDP protokolleri ile veri merkezine bağlantı sağlanarak, iki farklı çözünürlükte bir video dosyası oynatılarak bir saatlik süre içerisinde kullandığı bant genişlikleri karşılaştırılmıştır. Oluşturulan sonuçlarda düşük çözünürlükte bant genişliği kullanımının RDP ve Blast Extreme protokollerinin yakın olduğu görülmüştür. PCOIP’nin ise yüksek bant genişliği kullandığı gözlenmiştir.

This paper compares the performance and usage scenarios of virtualization products of four main architectures in detail, and analyses the advantages and characteristics of desktop virtualization solutions based on IDV architecture. According to the requirement of experiment teaching in public computer room and the actual use of software and hardware, a desktop virtualization computer experiment teaching management platform based on IDV architecture is constructed and successfully implemented. The related technologies and methods of environment construction are described in detail, and the problems encountered in the use of virtualization platform and the experience gained are discussed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.

The traditional language lab has many shortcomings, for example, teaching function is simple, teaching resource is not sufficient, management model is not uniform, system upgrade is not convenient and so on. Combined with the characteristics of college language lab in teaching and management and the advantages of cloud computing, a new speech lab was designed based on cloud computing and application scenarios. The speech lab has the characteristics of strong function, low cost, easy management and high security. Using cloud computing environment of language laboratory can greatly enrich the teachers^teaching methods, change traditional classroom teacher oriented teaching，also make teachers and students form one-to-one teaching, asynchronous teaching mode is possible. It greatly improves students^learning enthusiasm and initiative and teaching efficiency, can effectively reduce the equipment maintenance and management, and realizes the efficient management. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 VMsmigrate 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 VMon the consolidation server by copying onlyVM 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. [ABSTRACT FROM AUTHOR]

Existing desktop virtualization systems suffer from a very limited performance in replaying high-definition videos remotely: intolerable CPU and bandwidth consumption, high response delay and poor video quality. In this paper, we propose an original-stream based solution to provide good user experience for replaying high-definition videos in desktop virtualization systems without any modification on applications and support most of prevalent high-definition video formats. In our solution, server׳s video content is not decoded on server but intercepted and delivered to client in its originally encoded state, so that the video content can be easily stored and transported in computer systems with high quality and low bandwidth. The encoded video content is intercepted in server׳s display driver, which enables HDR to work seamlessly with existing applications. The extremely CPU-intensive video decoding tasks are executed on client by using GPU-accelerated video decoding technology so that CPU can concentrate on other tasks. The experimental results validate our method and show that this proposed approach measurably outperforms state-of-the-art solutions. [ABSTRACT FROM AUTHOR]

Through analyzing the design requirement of security desktop virtualization information system, this paper presents safety virtualization technology of "white list" security mechanism, virtualization layer security technology of optimization design, and virtual machine security technology of resources and network layer isolation. On the basis, the overall architecture of security desktop virtualization information system is built, and also the system realization and typical application scenario are given. Research in this paper provides a safe, easy management, low cost solution of desktop cloud architecture for enterprise, improves the level of core technology on cloud computing security, and promotes the development of independent controllable high security cloud computing products. [ABSTRACT FROM AUTHOR]

In order to solve the complexity and difficulties in laboratory management and maintenance, an overall and m-depth construction was made for the computer laboratory and multimedia classroom management supported by technology of desktop virtualization, and a comprehensive service system was proposed. Its design not only takes into consideration the requirements of management and maintenance staff as well as management department, but also takes full account of the various requirements of computer laboratory and multimedia classroom users. The system implemented can provide complete support and efficient comprehensive service to those requirements, hence, it gives a fine solution to the problems existing nowadays in the management, maintenance and the use of computer laboratories and multi-media classrooms in colleges and universities. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

With the continuous development of cloud computing, the virtual desktop solution becomes increasingly mature and the desktop virtualization becomes a typical cloud computing application. Virtual desktop technology can effectively solve those problems when using traditional personal computers and also reduce maintenance costs, which draws industries' attentions. As an open source desktop delivery protocol, SPICE has its own unique architecture and characteristics. Using SPICE protocol, virtual desktops can be deployed between servers and remote terminal clients with good quality of user experiences. However, SPICE protocol has its own drawbacks, and it is not suitable for low-bandwidth networks. Virtual desktop technology is introduced and the theories of virtual desktop delivery protocols as well as factors that affect virtual desktop performances are analyzed. Based on the analysis, the architecture of SPICE virtual desktop solution and its core technology are further analyzed. Finally the drawbacks of SPICE protocol are pointed out and some improvements methods without affecting QoE are proposed, which will play a guide role for the development of virtual desktop technology. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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Background: Cloud-based desktop virtualization infrastructure (VDI) is known as providing simplified management of application and desktop, efficient management of physical resources, and rapid service deployment, as well as connection to the computer environment at anytime, anywhere with anydevice. However, the economic validity of investing in the adoption of the system at a hospital has not been established. Methods: This study computed the actual investment cost of the hospital-wide VDI implementation at the 910-bed Seoul National University Bundang Hospital in Korea and the resulting effects (i.e., reductions in PC errors and difficulties, application and operating system update time, and account management time). Return on investment (ROI), net present value (NPV), and internal rate of return (IRR) indexes used for corporate investment decision-making were used for the economic analysis of VDI implementation. Results: The results of five-year cost-benefit analysis given for 400 Virtual Machines (VMs; i.e., 1,100 users in the case of SNUBH) showed that the break-even point was reached in the fourth year of the investment. At that point, the ROI was 122.6%, the NPV was approximately US$192,000, and the IRR showed an investment validity of 10.8%. From our sensitivity analysis to changing the number of VMs (in terms of number of users), the greater the number of adopted VMs was the more investable the system was. Conclusions: This study confirms that the emerging VDI can have an economic impact on hospital information system (HIS) operation and utilization in a tertiary hospital setting. [ABSTRACT FROM AUTHOR]