Elastic SI-Cache: consistent and scalable caching in multi-tier architectures

The new vision of cloud computing demands scalable, available and autonomic software platforms in order to deploy applications and services accessible anywhere and anytime. Multi-tier architectures are an important building block for many applications that are deployed in the cloud. This paper presents a novel caching and replication infrastructure that facilitates the scalable and elastic deployment of multi-tier architectures. Our Elastic SI-Cache is a novel multi-version cache that attains high performance and consistency in multi-tier systems. In contrast to most existing caches, Elastic SI-Cache provides snapshot isolation coherently across all tiers. Furthermore, Elastic SI-Cache supports scalable replication of the different tiers where replicas can be added or removed dynamically as needed, making the cache amenable for cloud computing environments. Elastic SI-Cache has been implemented and integrated into an open source JEE application server and its performance evaluated with the industrial benchmark SPECjAppServer.     

Keynote paper: Architectures for integrating manufacturing activities and enterprises

This paper is a summary of the major technical report (Williams et al., 1993) of the IFAC/IFIP Task Force on Architectures for Integrating Manufacturing Activities and Enterprises. It presents a synopsis of the investigations of pertinent architectures undertaken, and the findings generated relating to the suitability of various architectures for the integration task. It also presents the Task Force's recommendations for achieving a “complete” architecture in terms of the necessary capabilities by “completing” a currently available architecture. The Task Force also outlined how a “best” architecture could be achieved by selecting and combining the best features of the available architectures.     

Optimal resource allocation in synchronized multi-tier Internet services

Modern Internet systems have evolved from simple monolithic systems to complex multi-tiered architectures. For these systems, providing good response time performance is crucial for commercial success. In practice, the response-time performance of multi-tiered systems is often degraded by severe synchronization problems, causing jobs to wait for responses from different tiers. Synchronization between different tiers is a complicating factor in the optimal control and analysis of performance. In this paper, we study a generic multi-tier model with synchronization in a queuing-theoretical setting. The system is able to share processing capacity between arriving jobs that need to be sent to other tiers and the responses that have arrived after processing from these tiers. We provide structural results on the optimal resource allocation policy and provide a full characterization of the policy in the framework of Markov decision theory. We also highlight important effects of synchronization in the model. We validate our expressions through extensive experimentations for a wide range of resource configurations.     

Research and Development on Manufacturing Enterprise Integration Framework

Currently many enterprises have established some independent application systems such as CAD, CAPP, CAE and so on. Enterprise information integration makes these information islands connected, and thereby forms a uniform enterprise-wide information environment. First this paper discusses the main research contents of enterprise integration. Then the author introduces an Internet-based configurable and open information integration framework, and presents a multi-tier integration architecture based on reusable component. Finally a development case of enterprise integration framework is introduced.     

基于多层分布式结构技术的企业物资管理信息系统

介绍了多层分布式结构技术的特点,并以企业物资管理信息系统为例阐述了应用多层分布式结构技术建设系统的方法,该方法还可用于其他信息系统的开发。     

Case studies of dissemination policy in local government GIS agencies

This article presents the results of master's thesis work titled “Information Policy for Local Government Geographic Information Systems: Adoption, Implementation and Results”. Through analysis of six case studies of dissemination policy adoption, implementation and results in local government GIS agencies, the article adds substantive information to the ongoing debate over dissemination policy among GIS practitioners and academics. The work presents a brief introduction to the legal and practical issues relevant to GIS dissemination policy, identifies the main points of interest in each case study, compares and analyzes the case study observations, identifies new information about dissemination policy adoption, implementation and results, and discusses important areas for further research. This article, then, contributes new information and an informed perspective to the ongoing debate over how local and regional government GIS agencies should provide public access to their spatial data.     

多层体系结构中一个以数据为中心的设计方法

软件解决方案所面临的问题是在部署体系结构时不断增加的多态性、复杂性和分布性,这只能使问题复杂化.随着互联网络技术的出现,系统设计者必须重新评估多层体系结构的适用性,并且评定对每一层来说哪些技术是适用的.这篇文章重新评估多层体系结构中的设计问题,讨论在应用程序间的消息传递中,认为传送代码还是传送数据是比较好的方法.基于J2EE和.NET架构技术,文章最后推荐一个多层体系结构中一个以数据为中心的设计;根据已有的经验,建议软件开发中同样提出一个改良的交互式软件过程的螺旋模型.     

Bane or Boon? What the CEO Really Thinks of MIS

To answer the question, “What do CEOs think about information systems? ” first step back and ask, “What do CEOs normally think about? ”Effective CEOs spend almost all of their time thinking about problems and opportunities, and the information systems department that presents either is sure to get the CEO's attention.     

Non-hierarchical control of a flexible manufacturing cell

As hierarchically controlled computer-integrated manufacturing systems growthey tend to become complex and their designability, maintainability, expandability and fault tolerance deteriorate. As an alternative, herterarchical control architectures offer prospects of reduced compexity, reduced software development costs, high modularity, high flexibility, and improved fault tolerance. By locating decision making where information originates, global information is reduced to a minimum, scheduling becomes dynamic, machines and parts become “intelligent” entities that cooperatively interact, and the overall system is decomposed into functionally simplified, modular parts.Three flexible machining cell control systems have been constructed at the University of Wisconsin-Madison and are described in this paper: a centralized controller, a hierarchical controller with dynamic scheduling, and a fully distributed heterarchical controller with “intelligent parts”. Comparative results are reported showing that the heterarchical approach possesses a number of advantages including increased fault-tolerance, inherent adaptability and reconfigurability, decreased complexity, and reduced software development cost.     

Fifth generation and VLSI architectures

Most Western Governments (USA, Japan, EEC, etc.) have now launched national programmes to develop computer systems for use in the 1990s. These so-called Fifth Generation computers are viewed as “knowledge” processing systems which support the symbolic computation underlying Artificial Intelligence applications. The major driving force in Fifth Generation computer design is to efficiently support very high level programming languages (i.e. VHLL architecture).

Historycally, however, commercial VHLL architectures have been largely unsuccesful. The driving force in computer designs has principally been advances in hardware which at the present time means architectures to exploit very large scale integration (i.e. VLSI architecture).

This paper examines VHLL architectures and VLSI architectures and their probable influences on Fifth Generation computers. Interestingly the major problem for both architecture classes is parallelism; how to orchestrate a single parallel computation so that it can be distributed across an ensemble of processors.     

Deriving Long-Term Value from Context-Aware Computing

Modern businesses are increasingly dynamic in nature, which creates a need for computer systems that can sense and respond to rapid changes in the environment, or “context,” of the enterprise. This article presents the authors' vision of a context “ecosystem” that helps enterprises, applications, and developers respond to these dynamic changes and derive long-term value from context information. the ecosystem includes providers of raw context information, components that derive more abstract context information from lower level sources, middleware that provides systematic context services to applications, development tools, and contextaware applications.     

Personalization of internet telephony services for presence with SIP and extended CPL

This paper discusses issues of personalization of presence services in the context of Internet Telephony. Such services take into consideration the willingness and ability of a user to communicate in a network, as well as possibly other factors such as time, address, etc. Via a three-layer service architecture for communications in the session initiation protocol (SIP) standard, presence system basic services and personalized services (personal policies) are clearly separated and discussed. To enrich presence related services, presence information is illustratively extended from the well known “online” and “offline” indicators to a much broader meaning that includes “location”, “lineStatus”, “role”, “availability”, etc. Based on this, the call processing language (CPL) is extended in order to describe presence related personalized services for both call processing systems and presence systems using information such as a person’s presence status, time, address, language, or any of their combinations. A web-based system is designed and implemented to simulate these advanced services. In the implementation, personal policies are programmed by end users via a graphic user interface (GUI) and are automatically translated into extended CPL. The simulation system clearly displays when, where and what CPL policies should be used for the provision of personalized presence services and call processing services. Policy conflicts are also addressed by setting policy priorities in the system.     

Architectural requirements for rapid development of agile manufacturing systems

As product life cycle becomes shortened, high product quality becomes necessary for survival, and continuous and unexpected change becomes key obstacles in success, the need for a method of rapidly and cost-effectively developing products, production facilities and supporting software including design, process planning, shop floor control systems becomes urgent. The essence of this concept of manufacturing would be characterized by adopting a new term “agility”. Agile manufacturing can be successfully accomplished using various well-defined system architecture. This paper provides a primary sketch of architectural requirements for rapid development of agile manufacturing systems.There are several aspects of system architecture : control, function, process, information, communication, distribution, development, and implementation.In the past, the confusion of those architectures prohibited the successful construction of the automated CIM systems.     

On the almost-sure sample stability of systems with randomly time-varying delays

In a large class of multi-loop control systems, many feedback loops are “closed” through a time-shared digital computer, by means of algorithms which require information from sources which are sampled at a rate which is not synchronized with the sampling of the individual “plants”. This mis-synchronization, coupled with variations in the computer's task load caused by “interrupts”, results in a randomly time-varying delay in the closing of the various feedback loops. Consequently, the dynamics of each controlled “plant” in such a system may be modeled by means of a stochastic delay-differential equation. This paper presents some new research results concerning the sample stability, as opposed to statistical, or ensemble stability, of linear stochastic delay-differential equations.     

CAD — State of the art and a tentative forecast

The most important contemporary phenomenon in the mechanical engineering applications of CAD is the very rapid proliferation of systems, even in small and medium companies, driven by market imperatives and attracted by vastly improved cost/performance indices. The systems have expanded “upwards” from drafting to the modelling and analysis areas and “downstream” to process planning and documentation.Outstanding trends for the future are the use of knowledge-engineering techniques for problem solving, of novel database structures for intergrating data-growth over the product cycle, and of distributed architectures for building cooperative systems.     

It Strategies for Migrating to the EURO

In IT circles, converting systems to the euro is considered the next “Y2K.” Whereas Y2K involved correcting a set of dates, euro conversion involves currency regulations of the European Monetary Union (EMU) as well as those of the EMU member countries. Thus, migrating to the euro is far more complex than solving Y2K. To help IT managers cope with the difficulties of converting systems to the euro, the Euro Working Group (EWG) was formed. in this article, the chairman of the EWG presents the group's strategies for switching information systems to the new currency.     

Internet Technologies for Improving Data Access

The term “Internet technologies” has recently been coined to describe a set of software capabilities aimed at improving data communications and data access in contemporary enterprise information systems. This article presents a framework for implementing Internet technologies to improve enterprisewide data access, particularly in terms of the user interface, communications networking, the application platform, and the hardware operating systems platform. Examples of software products are given to illustrate how Internet technologies affect these platforms.     

An it Architecture for Nimble Organizations: Managing Access from Cyberspace

In today's world of “co-opetition” among organizations, where one organization competes and cooperates simultaneously with business partners, all organizations must have IT architectures that are nimble and flexible. This article takes a look at one important aspect in achieving a flexible IT architecture: access management of information resources over the Web. It describes an access management architecture that can change as business does and recommends how best to implement this nimble architecture.     

Learning in analog neural network hardware

Hardware implementations of neuroprocessor architectures are currently enjoying commercial availability for the first time ever. This development has been caused in part by the requirement for real-time solutions to time critical neural network applications. Massively parallel asynchronous neuromorphic representations are inherently capable of very high computational speeds when properly cast in the “right stuff”, i.e. electronic or optoelectronic hardware. However, hardware based learning in such systems is still at a primitive stage. In practise, simulations are typically performed in software, and the resulting synaptic weight capturing the input-output transformation subsequently quantized and down-loaded onto the neural hardware. However, because of the numerous discrepancies between the software and hardware, such systems are inherently poor in performance. In this paper we report on chip-in-the-loop learning systems assembled from custom analog “building blocks” hardware.