The Design of Distributed Service Systems

A variety of practical situations involve supplying a particular commodity by some locations to satisfy the demand at others. If the demands and the costs of producing varying amounts of commodity at each location are known, then the question is how much commodity should be supplied by each location in order to minimize the total system cost. Under some relatively general conditions, there will be an optimal solution with the property that the vector of amounts supplied by the various locations is one of a distinguished set of points. In the case of star networks, this combinatorial nature may be exploited to give a very efficient algorithm for finding an optimal solution. A numerical example illustrates the results

Interaction systems design and the protocol- and middleware-centred paradigms in distributed application development

This paper aims at demonstrating the benefits and importance of interaction systems design in the development of distributed applications. We position interaction systems design with respect to two paradigms that have influenced the design of distributed applications: the middleware-centred and the protocol-centred paradigm. We argue that interaction systems that support application-level interactions should be explicitly designed, using the externally observable behaviour of the interaction system as a starting point in interaction systems design. This practice has two main benefits: to promote a systematic design method, in which the correctness of the design of an interaction system can be assessed against its service specification; and, to shield the design of application parts that use the interaction system from choices in the design of the supporting interaction system

Upon a Message-Oriented Trading API

In this paper, we introduce the premises for a trading system application-programming interface (API) based on a message-oriented middleware (MOM), and present the results of our research regarding the design and the implementation of a simulation-trading system employing a service-oriented architecture (SOA) and messaging. Our research has been conducted with the aim of creating a simulation-trading platform, within the academic environment, that will provide both the foundation for future experiments with trading systems architectures, components, APIs, and the framework for research on trading strategies, trading algorithm design, and equity markets analysis tools. Mathematics Subject Classification: 68M14 (distributed systems).Trading System API, Straight-Through Processing, Distributed Computing, Service-Oriented Architecture (SOA), Message-Oriented Middleware (MOM), Java Message Service (JMS), OpenMQ

ASETS – An Academic Trading Simulation Platform

This paper is intended to present the results of our academic research upon a distributed computing environment dedicated to trading simulation. Our research has been conducted with the aim of creating a trading simulation platform, that would provide both the foundation for future experiments with trading systems architectures, components, APIs, and the framework for research on trading strategies, trading algorithms design, and equity markets analysis tools.Trading Systems, Simulation, Distributed Computing, Service-Oriented Architecture (SOA), Message-Oriented Middleware (MOM), Java Message Service (JMS)

Model-driven design of geo-information services

This thesis presents a method for the development of distributed geo-information systems. The method is organised around the design principles of modularity, reuse and replaceability. The method enables the modelling of both behavioural and informational aspects of geo-information systems in an integrated way. This thesis introduces the concept the Geo-information Service Infrastructure (GSI)

Dynamic Model-based Management of Service-Oriented Infrastructure.

Models are an effective tool for systems and software design. They allow software architects to abstract from the non-relevant details. Those qualities are also useful for the technical management of networks, systems and software, such as those that compose service oriented architectures. Models can provide a set of well-defined abstractions over the distributed heterogeneous service infrastructure that enable its automated management. We propose to use the managed system as a source of dynamically generated runtime models, and decompose management processes into a composition of model transformations. We have created an autonomic service deployment and configuration architecture that obtains, analyzes, and transforms system models to apply the required actions, while being oblivious to the low-level details. An instrumentation layer automatically builds these models and interprets the planned management actions to the system. We illustrate these concepts with a distributed service update operation

GRIDCC - Providing a real-time grid for distributed instrumentation

The GRIDCC project is extending the use of Grid computing to include access to and control of distributed instrumentation. Access to the instruments will be via an interface to a Virtual Instrument Grid Service (VIGS). VIGS is a new concept and its design and implementation, together with middleware that can provide the appropriate Quality of Service (QoS), is a key part of the GRIDCC development plan. An overall architecture for GRIDCC has been defined and some of the application areas, which include distributed power systems, remote control of an accelerator and the remote monitoring of a large particle physics experiment, are briefly discussed.E

Towards Stabilization of Distributed Systems under Denial-of-Service

In this paper, we consider networked distributed systems in the presence of Denial-of-Service (DoS) attacks, namely attacks that prevent transmissions over the communication network. First, we consider a simple and typical scenario where communication sequence is purely Round-robin and we explicitly calculate a bound of attack frequency and duration, under which the interconnected large-scale system is asymptotically stable. Second, trading-off system resilience and communication load, we design a hybrid transmission strategy consisting of Zeno-free distributed event-triggered control and Round-robin. We show that with lower communication loads, the hybrid communication strategy enables the systems to have the same resilience as in pure Round-robin

The Impacts of Spatially Variable Demand Patterns on Water Distribution System Design and Operation

Open Access articleResilient water distribution systems (WDSs) need to minimize the level of service failure in terms of magnitude and duration over its design life when subject to exceptional conditions. This requires WDS design to consider scenarios as close as possible to real conditions of the WDS to avoid any unexpected level of service failure in future operation (e.g., insufficient pressure, much higher operational cost, water quality issues, etc.). Thus, this research aims at exploring the impacts of design flow scenarios (i.e., spatial-variant demand patterns) on water distribution system design and operation. WDSs are traditionally designed by using a uniform demand pattern for the whole system. Nevertheless, in reality, the patterns are highly related to the number of consumers, service areas, and the duration of peak flows. Thus, water distribution systems are comprised of distribution blocks (communities) organized in a hierarchical structure. As each community may be significantly different from the others in scale and water use, the WDSs have spatially variable demand patterns. Hence, there might be considerable variability of real flow patterns for different parts of the system. Consequently, the system operation might not reach the expected performance determined during the design stage, since all corresponding facilities are commonly tailor-made to serve the design flow scenario instead of the real situation. To quantify the impacts, WDSs’ performances under both uniform and spatial distributed patterns are compared based on case studies. The corresponding impacts on system performances are then quantified based on three major metrics; i.e., capital cost, energy cost, and water quality. This study exemplifies that designing a WDS using spatial distributed demand patterns might result in decreased life-cycle cost (i.e., lower capital cost and nearly the same pump operating cost) and longer water ages. The outcomes of this study provide valuable information regarding design and operation of water supply infrastructures; e.g., assisting the optimal design

Transparent Dynamic reconfiguration for CORBA

Distributed systems with high availability requirements have to support some form of dynamic reconfiguration. This means that they must provide the ability to be maintained or upgraded without being taken off-line. Building a distributed system that allows dynamic reconfiguration is very intrusive to the overall design of the system, and generally requires special skills from both the client and server side application developers. There is an opportunity to provide support for dynamic reconfiguration at the object middleware level of distributed systems, and create a dynamic reconfiguration transparency to application developers. We propose a Dynamic Reconfiguration Service for CORBA that allows the reconfiguration of a running system with maximum transparency for both client and server side developers. We describe the architecture, a prototype implementation, and some preliminary test result