distributed application programmers rely on middleware such as CORBA in order to handle the complexity that arises from the distributed and heterogeneous nature of the underlying computing platform. CORBA, in particul...
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distributed application programmers rely on middleware such as CORBA in order to handle the complexity that arises from the distributed and heterogeneous nature of the underlying computing platform. CORBA, in particular, provides a media streaming mechanism that can be used both for media streaming and for associating QoS requirements with media streams. Despite defining the interfaces of the media streaming mechanism, the corresponding specification does not prescribe how QoS is enforced at low levels by the middleware. This paper describes the design and implementation of a QoS architecture, called Quartz, which has been integrated with CORBA in order to provide a framework that allows applications to transfer real-time media in open systems. This framework is employed to model and simulate a pattern recognition mechanism for use in an automated manufacturing cell, which is also described and analysed in this paper.
Proposes an application framework for mobile agents which provides rule-based generic services to support the three phases of a market transaction (information phase, contracting phase and settlement phase). It is des...
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Proposes an application framework for mobile agents which provides rule-based generic services to support the three phases of a market transaction (information phase, contracting phase and settlement phase). It is described within the four views of an electronic market (the business view, the transaction view, the services view and the infrastructure view) which describe organizational as well as technological aspects. The focus of this paper is on the technological aspects of the contracting phase in which the participating agents carry out an automated negotiation process to determine the terms of contract.
This paper describes an architecture that provides support for quality of service (QoS) specification and enforcement in heterogeneous distributed computing systems. The Quartz QoS architecture has been designed to ov...
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This paper describes an architecture that provides support for quality of service (QoS) specification and enforcement in heterogeneous distributed computing systems. The Quartz QoS architecture has been designed to overcome various limitations of previous QoS architectures that have constrained their use in heterogeneous systems. These limitations include dependencies on specific platforms and the fact that their functionality is often limited by design to one particular area of application. Quartz is able to accommodate differences among diverse computing platforms and areas of application by adopting a flexible and extensible platform-independent design, which allows its internal components to be rearranged dynamically in order to adapt the architecture to the surrounding environment. Further significant problems found in other QoS architectures, such as the lack of flexibility and expressiveness in the specification of QoS requirements and limited support for resource adaptation, are also addressed by Quartz. This paper describes the motivations for and design of Quartz in detail, presents a prototype implementation of Quartz and an analysis of its design based on experience with a number of applications that use this prototype.
An approach to implement strategies for automated negotiations in electronic commerce applications is presented. It is based on genetic algorithms (GAs) that evolve FSMs (finite state machines). Each of these FSMs rep...
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ISBN:
(纸本)0769506801
An approach to implement strategies for automated negotiations in electronic commerce applications is presented. It is based on genetic algorithms (GAs) that evolve FSMs (finite state machines). Each of these FSMs represents a negotiation strategy that competes against other strategies and is modified over time according to the outcome of this competition by using GA principles. The paper gives an overview of negotiating agents and work related to the paper. Then the application of genetic algorithms to FSMs is presented and relevant details on the implementation are given.
This paper presents a series of experiments that were conducted to investigate in the nonstationary behavior of a wafer fab after changes in product mix. The experiments were performed using a simulation model of the ...
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This paper presents a series of experiments that were conducted to investigate in the nonstationary behavior of a wafer fab after changes in product mix. The experiments were performed using a simulation model of the front end area of an existing semiconductor fab. We observe how short-term increases in wafer starts of a product influence the cycle time and WIP of this product and of the other products. It is examined how the fab recovers from such production surges under different dispatch rules. We also investigate how different lot start mechanisms affect the short term fab performance. More specifically, we observe the effects of changing the mix of the lots started into the fab on a weekly basis. Finally, we compare two alternative ways of releasing lots into the fab: the first is to distribute lot starts evenly over a given period, e.g. a week, and the other is to start all lots at the beginning of the period.
Our previous work in mobility support for CORBA applications resulted in the design and implementation of the Architecture for Location-Independent CORBA Environments (ALICE). The first version of ALICE enabled CORBA ...
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ISBN:
(纸本)078037133X
Our previous work in mobility support for CORBA applications resulted in the design and implementation of the Architecture for Location-Independent CORBA Environments (ALICE). The first version of ALICE enabled CORBA objects running on mobile devices to interact transparently with objects hosted by off-the-shelf CORBA implementations without relying on a centralised location register to keep track of their whereabouts. This paper presents the second version of ALICE on which work is ongoing. The improved architecture retains the features of the original and adds support for disconnected operation in the form of caching of server functionality on the client side. Furthermore, the architecture is being generalised beyond CORBA in order to make it applicable to other distribution infrastructures, such as Java RMI and DCOM.
Scalability is recognised as a primary factor to be considered in the design of distributedsystems. The scalability of object-oriented middleware CORBA is becoming a major concern as it has emerged as a standard arch...
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Scalability is recognised as a primary factor to be considered in the design of distributedsystems. The scalability of object-oriented middleware CORBA is becoming a major concern as it has emerged as a standard architecture for distributed object computing. In this paper, a systematic scalability analysis of the basic components of the CORBA specification is attempted. From this analysis, the Portable Object Adapter (POA) and the Implementation Repository (IR) are identified to influence the scale of a CORBA-based system. The specification of the POA provides enough feasibility for the application designer to handle scalability. The existing implementations of IR have a tradeoff between scalability and object migration. A scalable design of the IR is proposed which allows individual objects to migrate without compromising scalability. A performance comparison of the proposed model with existing IR designs is made using a simulation study.
Patterns are a means for capturing experience in solving general problems. They give general solutions to common and recurring problems. They exist at various phases of the software development life-cycle (SDLC), name...
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Patterns are a means for capturing experience in solving general problems. They give general solutions to common and recurring problems. They exist at various phases of the software development life-cycle (SDLC), namely the analysis phase, the design phase, the coding phase and the testing phase. Patterns in each phase are identified independently. It is possible for the patterns of one phase to be related to patterns in other phases. This paper proposes pattern mapping to inter-relate the patterns of various phases in SDLC to address this issue. It is advantageous to capture the related patterns of different phases as a single unit for software development. Reusable integrated components (ICs) of patterns are proposed to capture the related patterns. A software IC is a group of inter-related patterns, that gives solutions for a recurring problem at various phases of SDLC. A representation mechanism for ICs is presented using the URA (Unified Representation of an Artifact) model, which captures the software development process. Also, this paper proposes a software development process that is based on reusable ICs of patterns. The representation of a software project developed using ICs is also discussed.
Data distribution management (DDM) is one of the services defined by the DoD High Level Architecture. DDM is necessary to provide efficient, scalable mechanisms for distributing state updates and interaction informati...
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Data distribution management (DDM) is one of the services defined by the DoD High Level Architecture. DDM is necessary to provide efficient, scalable mechanisms for distributing state updates and interaction information in large scale distributed simulations. We describe data distribution management mechanisms (also known as filtering) used for real time training simulations. We propose a new DDM approach to multicast group allocation, which we refer to as a dynamic grid-based allocation. Our scheme is based on a combination of a fixed grid-based method, known for its low overhead and ease of implementation, and a sender-based strategy, which uses fewer multicast groups than the fixed grid-based method. We describe our DDM algorithm, its implementation, and report on the performance results that we have obtained using the RTI-Kit framework. These results include the outcome of experiments comparing our approach to the fixed grid-based method, and they show that our scheme is scalable and significantly reduces the message overhead of previous grid-based allocation schemes.
In this paper we present an active video module that consists of a miniature video sensor, a wireless video transmitter and a pan-tilt mechanism driven by micromotors. The video module is part of a miniature mobile ro...
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In this paper we present an active video module that consists of a miniature video sensor, a wireless video transmitter and a pan-tilt mechanism driven by micromotors. The video module is part of a miniature mobile robot that is projected to areas of the environment to be surveyed. A single-chip CMOS video sensor and miniature brushless DC gearmotors are used to comply with restrictions imposed by the robotic system in terms of payload weight volume and power consumption. Different types of actuation are analyzed for compatibility with a mesoscale robotic system. Applications of an active video module are discussed.
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