Distributed Service System Research Articles

Evolving RPC for active storage

We introduce Scriptable RPC (SRPC), an RPC-based framework that enables distributed system services to take advantage of active components. Technology trends point to a world where each component in a system (whether disk, network interface, or memory) has substantial computational capabilities; however, traditional methods of building distributed services are not designed to take advantage of these new architectures, mandating wholesale change of the software base to exploit more powerful hardware. In contrast, SRPC provides a direct and simple migration path for traditional services into the active environment.We demonstrate the power and flexibility of the SRPC framework through a series of case studies, with a focus on active storage servers. Specifically, we find three advantages to our approach. First, SRPC improves the performance of distributed file servers, reducing latency by combining the execution of operations at the file server. Second, SRPC enables the ready addition of new functionality; for example, more powerful cache consistency models can be realized on top of a server that exports a simple NFS-like interface. Third, SRPC simplifies the construction of distributed services; operations that are difficult to coordinate across client and server can now be co-executed at the server, thus avoiding costly agreement and crash-recovery protocols.

A Rule-Based Expert System with Colored Petri Net Models for Distribution System Service Restoration

A Rule-Based Expert System with Colored Petri Net Models for Distribution System Service Restoration

Distribution system service restoration using fuzzy Petri Net models

This paper proposes a new fuzzy Petri Net (FPN) modeling technique to achieve the on-line service-restoration plan of the distribution system. Service restoration is a complicated combinatorial optimization problem that often has a great number of candidate solutions to be selected by the dispatchers. According to practical guidelines and experiences of the dispatchers on the service restoration of distribution systems, an FPN model is built to represent the related knowledge and inference scheme about the task of restoration. The proposed FPN model has been practically tested on a typical distribution system of Taiwan Power Company (TPC). Flexibility and effectiveness of the FPN model have been validated as a decision support for restoration scheduling of distribution systems.

QoS-based evaluation of file systems and distributed system services for continuous media provisioning

This paper presents a QoS-based performance analysis of file systems and distributed object services for Continuous Media (CM) provisioning, as well as the details and implementation experiences of a continuous media file system and associated CM servers. For this we have implemented QoS-driven CM servers and the Presto continuous media file system (PFS) in the context of a distributed multimedia application development environment, and validate the performance of PFS against that of the conventional Unix file system through an experimental evaluation. Using our CM server prototype, we next examine the effect of continuous media data delivery on the three different kinds of network protocols such as CORBA, UDP/IP, and TCP/IP, with respect to QoS provisioning and throughput.

Intelligent mobile agents in large distributed autonomous cooperative systems

A large distributed autonomous cooperative system is a system that provides fundamental services for integrating high-level services in a large distributed system with local autonomy for individual system platforms and processes. This paper discusses the role and the functions of Intelligent Mobile Agents (IMAs) in large distributed autonomous cooperative systems. Rather than providing services to a user at the application level, IMAs considered in this paper are deemed an integral part of system level software and perform tasks that are considered central to the distributed system. A variety of solutions to problems that are inherent to the distributed nature of the computing infrastructure may be implemented through a system of IMAs. These problems include, but are by no means limited to, load balancing, scheduling, information retrieval and management, distributed decision support, routing and flow control, security and intrusion detection. In this paper we discuss some of characteristics of IMA based systems central to solving some of these problems. The effectiveness of IMAs in large distributed systems clearly depends on the design and implementation of the underlying IMA architecture. This paper discusses the features that must be provided by the IMA infrastructure in support of IMAs that are an integral part of the large distributed autonomous cooperative system.

Network nirvana and the intelligent device

Sun's Jini technology can make a network look like one large computer. The technology will let developers and manufacturers create a whole range of computerized appliances that can instantly connect into a network to share information and services regardless of the underlying operating system or hardware. Once connected, every other computer, device, and user on the network will know that the new device has been added and is available. If Sun succeeds in getting developers to implement and improve Jini, it will have a tremendous impact on networking, especially for wireless and mobile users. Devices in a Jini distributed system provide their own interfaces, which ensures reliability and compatibility. Jini provides the distributed-system services for lookup, registration, and leasing. It consists of four program layers: directory service; JavaSpace; remote-method invocation; and the boot, join, and discover protocol. Any device with an operating system that supports a Java virtual machine can be plugged into the network. The author discusses the origins of Jini, its functions and its competition.

Management of Value-Added Services in theTrading-Based System AGORA

Trading based systems are tailored to handle a complex number of system resources in distributed, permanently changing environments. These resources are usually represented by their service descriptions offered to a trader. In contrast to the conventional approach in which a service is provided by only one service object, we propose an extended trading concept to maintain and to manage services in open distributed systems. It allows to mediate value-added services. These are either reliable services guaranteeing independence and autonomy of the service objects or complex services that are defined by the functional composition of existing services. They are done by the cooperation of different service objects. In this paper we present this extended trading approach and describe our system AGORA that implements the extended service model and the mediation of value-added service in an open distributed system.

Authentication services for computer networks and electronic messaging systems

The paper surveys the authentication services used by modern computer systems and presents the major operational authentication services employed by commercial companies, banking as well as government departments. As distributed system services are susceptible to a variety of threats mounted by intruders as well as legitimate users of the system, password-based authentication is not suitable for use on computer networks.

Service lines: their effect on microbiological quality

Water that stagnates for long periods in distribution system service lines is susceptible to increases in bacteria, which can be reduced by extensive flushing.The influence of service lines on the microbiological quality of drinking water was investigated. The microbial water quality in domestic service lines was found to differ from that in the main pipes of the distribution system. Differences in bacterial counts from the first flush of the service line and from the main pipe were generally more pronounced in service lines located near the plant. After a thorough flushing of the service line, however, tap water quality was found to be equivalent to that in the main pipe. Bacteriological parameters studied were total direct count after acridine orange staining, heterotrophic plate counts, total coliforms, and Aeromonas. Physicochemical parameters measured included temperature, oxidant residual, and total, dissolved, and biodegradable organic carbon. Lead and copper concentrations were determined in the first flush, after flushing the service line,

Customized Message Passing

Replacing traditional operating systems communication implementations with customized implementations increases the performance of parallel and distributed applications. This paper describes the design and implementation of customizable message passing systems. The customized message passing systems are generated using application-specific information such as the profile of an application's communication pattern. FFT, Simplex, and Cholesky are used as example parallel applications. The message passing system has also been customized for different types of distributed system services including a distributed scheduling facility. The customized message passing system likewise improves the performance of these facilities and enhances their scalability. As a practical concern, as there are a large number of possible optimizations, object-oriented frameworks are employed to organize the implementations and to facilitate the choice of optimizations.

Designing a system infrastructure for distributed programs

A distributed program is one that consists of several components distributed over a network of computers. The reliability of a distributed program is strongly affected by the behaviour of the underlying distributed system software platform. One of the most fundamental issues in improving the reliability of distributed programs is to provide a better environment within which these programs operate. This paper investigates the functional requirement of the infrastructure of a distributed operating system in anticipation of the goal of improving the reliability of distributed programs. It identifies the major problems that make the task of achieving high software quality hard to accomplish, then suggests possible functionality that is advisable for the system infrastructure to provide. The design and implementation of the new distributed system service are then described.

Endorsements, Licensing, and Insurance for Distributed System Services

Endorsements, Licensing, and Insurance for Distributed System Services

Middleware

article Free Access Share on Middleware: a model for distributed system services Author: Philip A. Bernstein One Microsoft Way, Redmond, WA One Microsoft Way, Redmond, WAView Profile Authors Info & Claims Communications of the ACMVolume 39Issue 2Feb. 1996 pp 86–98https://doi.org/10.1145/230798.230809Published:01 February 1996Publication History 324citation8,080DownloadsMetricsTotal Citations324Total Downloads8,080Last 12 Months450Last 6 weeks58 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

Endorsements, Licensing, and Insurance for Distributed System Services

Endorsements, Licensing, and Insurance for Distributed System Services

Distribution system service restoration using the artificial neural network approach and pattern recognition method

Service restoration of a distribution system is investigated by using artificial intelligence. The purpose is to reach a proper restoration plan for the unfaulted zone after a fault has been identified and isolated. To reduce the outage period and improve service reliability, the restoration plan must be devised in a very short period. In the paper, two approaches using artificial intelligence, i.e. the artificial neural network (ANN) approach and the pattern recognition method, are developed to determine the restoration plan in a very efficient manner. The effectiveness of the proposed approaches is demonstrated by the restoration of electricity service following a fault in a distribution system in Taipei, Taiwan. It is concluded from the example that a proper restoration plan can be reached very efficiently using the proposed approaches. Therefore, it can be used by distribution system operators to reach a restoration plan.

A heuristic based fuzzy reasoning approach for distribution system service restoration

A fuzzy reasoning approach is proposed for the service restoration of a distribution system. After the location of a fault has been identified and the faulted zone has been isolated, it is important for the operators to reach a proper service restoration plan in order to restore the electricity service outside the faulted zone. The operators tend to use their past experience and heuristic rules to devise such a restoration plan because it must satisfy a lot of practical needs and objectives. In addition, the operators' needs and heuristic rules are often expressed in imprecise linguistic terms. In this paper, fuzzy set notation is employed to deal with these imprecise linguistic variables and a set of fuzzy reasoning procedures are developed to implement the operators' heuristic rules. These procedures can be employed to solve the multiple-objective problem of service restoration described in imprecise linguistic variables. To demonstrate the effectiveness of the proposed fuzzy reasoning approach, service restoration on a distribution system within the service area of Taipei West District Office of Taiwan Power Company is examined. It is found that a proper restoration plan can be reached very efficiently by the proposed approach. >

A distributed location system for the active office

Distributed systems for locating people and equipment will be at the heart of tomorrow's active offices. Computer and communications systems continue to proliferate in the office and home. Systems are varied and complex, involving wireless networks and mobile computers. However, systems are underused because the choices of control mechanisms and application interfaces are too diverse. It is therefore pertinent to consider which mechanisms might allow the user to manipulate systems in simple and ubiquitous ways, and how computers can be made more aware of the facilities in their surroundings. Knowledge of the location of people and equipment within an organization is such a mechanism. Annotating a resource database with location information allows location-based heuristics for control and interaction to be constructed. This approach is particularly attractive because location techniques can be devised that are physically unobtrusive and do not rely on explicit user action. The article describes the technology of a system for locating people and equipment, and the design of a distributed system service supporting access to that information. The application interfaces made possible by or that benefit from this facility are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Distribution system load estimation and service restoration using a fuzzy set approach

An approach based on fuzzy set theory is developed to estimate the loads in a distribution system and to devise a proper service restoration plan following a fault. To estimate the loads on branching points without real-time meters, typical hourly load patterns for several types of days are established for commercial, industrial, and residential customers. These load patterns are characterized by some linguistic variables using fuzzy set notations. The load of a branching point is estimated through fuzzy set operations. With the estimated loads at hand, a heuristic search method is proposed in order to reach a restoration plan with minimal number of switching operations in a short time. To demonstrate the effectiveness of the proposed fuzzy approach, load estimation and service restoration on a distribution system within the service area of Taipei West District Office of Taiwan Power Company are examined. It is found that, following a fault event, a proper restoration plan can be reached very efficiently. Therefore, the proposed approach can provide valuable information to distribution system operators in reaching a service restoration plan.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Automatic reconfiguration in the presence of failures

The paper describes a new kind of distributed system service, the availability management service, responsible for ensuring that the critical services of a distributed system remain continuously available to users despite arbitrary numbers of concurrent node removals and node restarts caused by failures, maintenance, and growth. It stresses the main ideas behind this new service, and outlines a simple design that depends on the existence of synchronous membership and atomic broadcast group communication services. Extensions of this initial design to deal with asynchronous group communication services are also briefly discussed. >

Identifying Water Main Leaks With Trihalomethane Tracers

In this study, the trihalomethanes (THMs) chloroform and dichlorobromomethane, present in chlorinated drinking water, were used as tracer compounds to identify the presence of treated city water in samples of seepage collected at leak sites in the distribution system. Using physical and chemical tests such as alkalinity, hardness, conductivity, and pH, the origin of leakage water samples often could not be identified unequivocally as treated city water, groundwater, or raw river water. Purge‐and‐trap gas chromatographic analysis detected nanogram‐per‐litre to low microgram‐per‐litre levels of chloroform and dichlorobromomethane and can be used to positively identify traces of treated city water. The method was successfully applied to the analysis of distribution system main and service line leak samples.