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COMMUNICATIONS OF THE ACM 1992年第7期35卷 77-98页

作者： SINHA, A Microsoft Corp. Redmond WA

Two decades ago, the data processing industry was using powerful mainframes with the users sharing CPU cycles and data storage facilities. Access to the mainframes was tightly controlled by Management Information Systems departments and the only method of accessing the data from mainframes was through punched cards or primitive terminals. Thus, when PC came to the computing industry in the early 1980s, their growth was phenomenal, as they provided limited CPU cycles and data storage facilities on user desktops, user control over desktops, and user-friendly PC-based software. PC, however, were still incapable of handling data processing needs of most large businesses. Local area networks (LAN) provided the solution by connecting PC and mainframes. Today, a wide spectrum of client-server Systems (CSS) are being implemented to make information easily accessible to the end-user. With the growth of client-server systems, one can anticipate that most vendors of CSS components will work toward open systems, which are easy to integrate and will require less in-house development to fit in within the CSS.

关键词： client-server computing

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Ruminations on Fully Homomorphic Encryption in client-server computing Scenario

International Journal of Electronics and Information Enginee...

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International Journal of Electronics and Information Engineering 2018年第1期8卷 32-39页

作者： Zhengjun Cao Lihua Liu Yang Li

Fully homomorphic encryption (FHE) allows anyone to perform computations on encrypted data, despite not having the secret decryption key. Since the Gentry's work in 2009, FHE has become a hot topic. In this paper, we would like to stress that any computations performed on encrypted data are constrained intrinsically to the underlying domain (finite fields or rings). This restriction makes the primitive useless for the computations involving common arithmetic expressions and relational expressions, because of the incompatibility of numerical computation with underlying encoding transformation over finite domains. We want to reaffirm that cryptography uses modular arithmetic a lot in order to obscure and dissipate redundancies in plaintext, not to perform any numerical calculations. Thus FHE will be of little importance to client-server computing or cloud computing.

关键词： client-server computing Common Arithmetic Encryption Domain Fully Homomorphic Encryption Modular Arithmetic

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A strategy to manage cache consistency in a disconnected distributed environment

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IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2001年第7期12卷 686-700页

作者： Kahol, A Khurana, S Gupta, SKS Srimani, PK Cisco Syst Inc San Jose CA 95134 USA Telcordia Technol Morristown NJ 07960 USA Arizona State Univ Dept Comp Sci & Engn Tempe AZ 85287 USA Clemson Univ Dept Comp Sci Clemson SC 29634 USA

Modern distributed systems involving large number of nonstationary clients (mobile hosts, MH) connected via unreliable few-bandwidth communication channels are very prone to frequent disconnections. This disconnection may occur because of different reasons: The clients may voluntarily switch off (to save battery power), or a client may be involuntarily disconnected due to its own movement in a mobile network (hand-off, wireless link failures, etc.). A mobile computing environment is characterized by slow wireless links and relatively underprivileged hosts with limited battery powers. Still, when data at the server changes, the client hosts must be made aware of this fact in order for them to invalidate their cache, otherwise the host would continue to answer queries with the cached values returning incorrect data. The nature of the physical medium coupled with the fact that disconnections from the network are very frequent in mobile computing environments demand a cache invalidation strategy with minimum possible overheads. In this paper, we present a new cache maintenance scheme, called AS. The objective of the proposed scheme is to minimize the overhead for the MHs to validate their cache upon reconnection, to allow stateless servers, and to minimize the bandwidth requirement. The general approach is 1) to use asynchronous invalidation messages and 2) to buffer invalidation messages from servers at the MH's Home Location Cache (HLC) while the MH is disconnected from the network and redeliver these invalidation messages to the MH when it gets reconnected to the network. Use of asynchronous invalidation messages minimizes access latency, buffering of invalidation messages minimizes the overhead of validating MH's cache after each disconnection and use of HLC off-loads the overhead of maintaining state of MH's cache from the servers. The MH can be disconnected from the server either voluntarily or involuntarily. We capture the effects of both by using a single parame

关键词： caching client-server computing data consistency mobile computing performance analysis

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Wireless cache invalidation schemes with link adaptation and downlink traffic

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IEEE TRANSACTIONS ON MOBILE computing 2005年第1期4卷 68-83页

作者： Yeung, MKH Kwok, YK Univ Hong Kong Dept Elect & Elect Engn Hong Kong Hong Kong Peoples R China

Providing on-demand data access in client-server wireless networks is an important support to many interesting mobile computing applications. Caching frequently accessed data by mobile clients can conserve wireless bandwidth and battery power, at the expense of some system resources to maintain cache consistency. The basic cache consistency strategy is the use of periodic invalidation reports (IRS) broadcast by the server. Recently, IR-based approaches have been further improved by using additional updated invalidation reports (UIRs) (i.e., the IR+UIR algorithm) to reduce the long query latency. However, the performance of the IR+UIR approach in a practical system is still largely unknown. Specifically, previous results are based on two impractical simplifying assumptions: 1) broadcast traffic is error-free and 2) no other downlink traffic (e.g., voice) exists in the system. The first assumption is clearly unrealistic as signal propagation impairments (e.g., multipath fading) and, hence, packet reception failures are inevitable in a practical situation. The second assumption is also inapplicable in real life because mobile devices are usually multipurposed (e.g., a mobile phone equipped with a browser may be used for Web surfing while having a phone conversation). In this paper, we first study the performance of the IR+UIR approach under a realistic system model: The quality of the wireless channel is time-varying, and there are other downlink traffics in the system. Our simulation results show that query delay significantly increases as a result of broadcast error and the additional downlink traffics experience longer delay due to extended broadcast period. Exploiting link adaptation (i.e., transmission rate is adjusted dynamically according to channel quality), we then propose three schemes to tackle these two problems. Our results indicate that the proposed schemes outperform IR+UIR under a wide range of system parameters.

关键词： cache invalidation invalidation report (IR) link adaptation channel adaptive protocols wireless networks client-server computing system design simulations

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EVALUATION OF DISTRIBUTED FINITE-ELEMENT ALGORITHMS ON A WORKSTATION NETWORK

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ENGINEERING WITH COMPUTERS 1994年第1期10卷 45-62页

作者： BAUGH, JW SHARMA, SK 1. Department of Civil Engineering North Carolina State University 27695 Raleigh North Carolina USA

This paper discusses the design, implementation and evaluation of linear finite element programs that distribute their computations over a network of workstations. We consider five different algorithms based on direct, iterative and hybrid equation solvers, each of which partitions and maps the model domain across conventional network hardware. A software architecture based on the client-server model distributes the computations and, at the language level, Berkeley sockets enable communication between processes. We evaluate and describe the performance of these algorithms in terms of execution time and speed-up, and we conclude that distributed solvers, particularly those based on substructuring and static condensation, can be effective even on high-latency communication networks.

关键词： client-server computing COMPUTER NETWORKS DISTRIBUTED PROGRAMMING EQUATION SOLVING FINITE ELEMENT ANALYSIS

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SOFTWARE BOTTLENECKING IN client-server SYSTEMS AND RENDEZVOUS NETWORKS

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 1995年第9期21卷 776-782页

作者： NEILSON, JE WOODSIDE, CM PETRIU, DC MAJUMDAR, S Real-Time and Distributed Systems Group Carleton University Ottawa K1S 5B6 Canada

Software bottlenecks are performance constraints caused by slow execution of a software task. In typical client-server systems a client task must wait in a blocked state for the server task to respond to its requests, so a saturated server will slow down all its clients. A Rendezvous Network generalizes this relationship to multiple layers of servers with send-and-wait interactions (rendezvous), a two-phase model of task behavior, and to a unified model for hardware and software convention. software bottlenecks have different symptoms, different behavior when the system is altered, and a different cure from the conventional bottlenecks seen in queueing network models of computer systems, caused by hardware limits. The differences are due to the ''push-back'' effect of the rendezvous, which spreads the saturation of a server to its clients. The paper describes software bottlenecks by examples, gives a definition, shows bow they can be located and alleviated, and gives a method for estimating the performance benefit to be obtained. Ultimately, if all the software bottlenecks can be removed, the performance limit will be due to a conventional hardware bottleneck.

关键词： PERFORMANCE BOTTLENECKS CRITICAL SECTIONS SOFTWARE serverS client-server computing LAYERED QUEUING NETWORKS DISTRIBUTED SOFTWARE ENGINEERING

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Heterogeneous network computing: The next generation

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PARALLEL computing 1997年第1-2期23卷 121-135页

作者： Sunderam, V Department of Math and Computer Science Emory University Atlanta GA 30322 USA

Heterogeneous concurrent computing has emerged in recent times as an effective platform for high performance applications as well as for traditional distributed computing, Performance and functionality that such methodologies can provide, as well as their limitations and potential, have become reasonably well understood. In this paper, we discuss some selected aspects of heterogeneous computing in the context of the PVM system, and describe evolutionary enhancements to the system, These extensions, which involve performance optimization, light-weight processes, and client-server computing, suggest useful directions that the next generation of heterogeneous systems might follow, A prototype design of such a next-generation heterogeneous computing framework is also discussed.

关键词： network computing distributed computing communication PVM NAS parallel benchmark client-server computing threads

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Performance analysis of admission control algorithms based on reward optimization for real-time multimedia servers

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PERFORMANCE EVALUATION 1998年第2期33卷 89-112页

作者： Chen, IR Hsi, TH Virginia Polytech Inst & State Univ No Virginia Ctr Dept Comp Sci Falls Church VA 22403 USA Natl Cheng Kung Univ Inst Informat Engn Tainan 70101 Taiwan

We propose and analyze a class of admission control algorithms based on reward optimization for multimedia servers designed to provide on-demand services to clients in an environment where workload characteristics of clients can change dynamically. These admission control algorithms are developed based on two strategic choices, namely, "deterministic" or "best-effort" regarding quality of service (QoS) control, and "priority-reservation" or "no priority-reservation" regarding reservation control. We first formulate the design of admission control algorithms for real-time multimedia servers as a reward optimization problem, with the "reward" referring to the value which the system receives after servicing prioritized clients based on the QoS requested and delivered. Then, we derive closed-form solutions for the reward rate expressions which the system can possibly obtain as a result of applying these admission control algorithms and validate the analytical results with a simulated VBR video server. A physical interpretation is given for the best combination of strategic choices under which the system can obtain the best reward as a function of workload and cost characteristics of the clients. We demonstrate that the reward value which the system receives under our proposed admission control algorithms at optimizing conditions can be much higher than those under traditional admission control algorithms which do not consider reward optimization. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： multimedia servers admission control quality of service (QoS) capacity reservation client-server computing performance analysis

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Broadcast protocols to support efficient retrieval from databases by mobile users

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ACM TRANSACTIONS ON DATABASE SYSTEMS 1999年第1期24卷 1-79页

作者： Datta, A Vandermeer, DE Celik, A Kumar, V Georgia Inst Technol DuPree Coll Management Atlanta GA 30332 USA Tandem Comp Inc Cupertino CA 95014 USA Univ Missouri Dept Comp Sci & Telecommun Kansas City MO 64110 USA

Mobile computing has the potential for managing information globally. Data management issues in mobile computing have received some attention in recent times, and the design of adaptive broadcast protocols has been posed as an important problem. Such protocols are employed by database servers to decide on the content of broadcasts dynamically, in response to client mobility and demand patterns. In this paper we design such protocols and also propose efficient retrieval strategies that may be employed by clients to download information from broadcasts. The goal is to design cooperative strategies between server and client to provide access to information in such a way as to minimize energy expenditure by clients. We evaluate the performance of our protocols both analytically and through simulation.

关键词： adaptive broadcast protocols client-server computing energy conservation mobile databases

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client/server infrastructure: a case study in planning and conversion

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INDUSTRIAL MANAGEMENT & DATA SYSTEMS 1997年第5-6期97卷 222-&页

作者： deVries, WA Fleck, RA COLUMBUS STATE UNIV ABBOTT TURNEER SCH BUSINESSCOLUMBUSGA

Conversion to client/server systems from host-centric systems can be accomplished with careful attention to planning and development procedures. A key component in a successful conversion is a customized definition of client/server which complements the organization's mission. Another key component is the development of an infrastructure which includes hardware, software and people. The training of users and design personnel is crucial to successful conversion. Discusses definitions, strategies, hardware, software, and the pitfalls to be avoided.

关键词： client-server computing infrastructure interfaces planning

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