Computing power and molecular simulation methodology have improved dramatically over the past decade, and for some systems molecular models are reaching a point where they can provide information that approaches or su...
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Computing power and molecular simulation methodology have improved dramatically over the past decade, and for some systems molecular models are reaching a point where they can provide information that approaches or surpasses the quality of real experimental data. Molecular simulation can also be a potent tool for developing qualitative understanding, and this feature suggests widespread use of molecular simulation as a tool for teaching. Broader use of molecular simulation for these purposes requires tools that promote understanding and application of simulation software. We present an "object-oriented" view of molecular simulation that can help conceptualize and organize its elements, and discuss software development tools that we have constructed that enable non-experts in simulation or graphical programming to create instructive molecular simulations. We finish with an example of one such simulation applet, which we have used in the classroom. Tools described here are available on the web at ***/etomica. (C) 2002 Elsevier Science B.V. All rights reserved.
Workflow is an important class of applications in the daily business. A number of web-based workflow systems have been developed recently as a natural extension to traditional workflow systems to exploit the growing p...
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Workflow is an important class of applications in the daily business. A number of web-based workflow systems have been developed recently as a natural extension to traditional workflow systems to exploit the growing popularity of the Internet. However, most of them are designed based on the specific application at hand. In this paper, we distill out the fundamental elements of a workflow system into a general workflow framework. The framework provides appropriate application programming interfaces for programmers to fill in the application specific requirements of a workflow system at hand. This is realized through two object-wrappers: the Task interface and the Resource interface, which support the specification of the tasks involved in the workflow schedule and the resources accessed respectively. A major characteristic of the framework is that the particular workflow schedule under execution is fluid, in the sense that the tasks involved as well as their precedence relationships can be modified dynamically. Consistency constraints will be examined in this paper which determine when such modifications are allowed. To maximize flexibility, we adhere our design to the CORBA architecture, which has been becoming highly popular in recent years, thus allowing tasks and resources of different types to interoperate in our framework. We demonstrate the feasibility of our framework with a small prototype that allows tasks in a workflow system to be scheduled and executed.
The future Internet is expected to support applications with quality of service (QoS) requirements. For this end several mechanisms are suggested in the IETF to support signaling, one of the most promising among them ...
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ISBN:
(纸本)0769513816
The future Internet is expected to support applications with quality of service (QoS) requirements. For this end several mechanisms are suggested in the IETF to support signaling, one of the most promising among them is IntServ. In this paper, we study the relationship between the QoS implementing mechanism and application demands, and make a set of an improved applicationinterface beyond the stand RSVP API. Our goal is to provide an API friendly to applications, through extracting the key elements from the traffic parameters and reservation parameters which should be opaque to applications.
The architecture, interface, and functionality of the Windows application programming interface (API) make it difficult to master and use effectively, and contribute negatively to the safety, robustness, and portabili...
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The architecture, interface, and functionality of the Windows application programming interface (API) make it difficult to master and use effectively, and contribute negatively to the safety, robustness, and portability of the applications developed under it. The API is structured around a large and constantly evolving set of functions and is based on a problematic shared library implementation. The provided interfaces are complicated, nonorthogonal, abuse the type system, cause name-space pollution, and use inconsistent naming conventions. In addition, the functionality of the interface suffers from inconsistency, incompleteness, and inadequate documentation. application developers, programming tool vendors, and Microsoft should face the above problems and provide appropriate solutions. (C) 1998 Elsevier Science B.V. All rights reserved.
This paper presents the results of a low cost, PC-DSP based motion control system development. The Texas Instruments TMS320C31 floating point Digital Signal Processor is selected for the real-time hardware platform wh...
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ISBN:
(纸本)0819429791
This paper presents the results of a low cost, PC-DSP based motion control system development. The Texas Instruments TMS320C31 floating point Digital Signal Processor is selected for the real-time hardware platform while code development and user interface tasks reside on a standard, non real-time PC platform such as the Pentium/Windows 95 systems. An application programming interface (API) has been implemented to facilitate open architecture code development. Finally, application to the control of an Adept linear robotic workcell is made with 2 input shaper designs serving as the test algorithms.
Since the late 80s there are a growing need of the machine tool builders and the end users to have open architecture controllers. Different levels of openness can be defined analyzing the available research results an...
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Since the late 80s there are a growing need of the machine tool builders and the end users to have open architecture controllers. Different levels of openness can be defined analyzing the available research results and products. The main initiatives leading the current research in these efforts are the European OSACA, the American OMAC and the OSEC from Japan. A complex comparison of these projects and their goals and achievements is presented in this paper. It is stated that in their present form it is not possible to merge easily the three results to get a unified and potentially worldwide accepted open architecture controller.
For more than a decade NEC dominated the Japanese PC market with its PC-98 architecture, which was incompatible both with its major Japanese rivals and the global PC standard. However, NEC was powerless to prevent the...
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For more than a decade NEC dominated the Japanese PC market with its PC-98 architecture, which was incompatible both with its major Japanese rivals and the global PC standard. However, NEC was powerless to prevent the introduction of Japanese versions of Windows 3.1 and 95 that ran on its competitors' architectures as well as on the PC-98, unifying the Japanese PC market and creating a common set of application programming interfaces for all Intel-based Japanese PCs. The introduction of Windows rendered obsolete the large DOS-based software library that had provided strong positive externalities for the NEC architecture. Absent those advantages, the market share of the PC-98 standard fell from 60% to 33% in five years, and NEC finally abandoned the PC-98 in favor of the global standard. An examination of the unusual rise and fall of the PC-98 shows how victory in a standards competition can be negated by the introduction of a new architectural layer that spans two or more previously incompatible architectures.
application programming interfaces (API) for database systems should preserve both the strengths of the database management system and of the programming languages. In addition to this general objective, innovative co...
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Since emerging networked applications require a variety of different communication services, the number of communication subsystems and approaches to deliver flexible services has increased. Nevertheless, applications...
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ISBN:
(纸本)0819426660
Since emerging networked applications require a variety of different communication services, the number of communication subsystems and approaches to deliver flexible services has increased. Nevertheless, applications have to be programmed sufficiently on top of these communication subsystems. Providing an easy-to-use and intuitively programmable communication service for multimedia applications, an up-to-date application programming interface is needed. The developed approach offers an object-oriented interface for setting-up, accessing, and managing communication services. Moreover, these services may be of flexible nature, offering the potential to application programmers to specify communication requirements in a set of application-dependent Quality-of-Service (QoS) parameters. Service needs and communication demands are specified by, e.g., bandwidth requirements, delay bounds, or authentication requests. The developed and implemented application programming interface hides away communication-relevant information from applications and provides a set of efficient and stream-lined interface functions and operations.
Distributed multimedia applications require a variety of communication services. These services and different application requirements have to be provided and supported within: 1) end-systems in an efficient and integ...
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Distributed multimedia applications require a variety of communication services. These services and different application requirements have to be provided and supported within: 1) end-systems in an efficient and integrated manner, combining the precise specification of quality-of-service (QoS) requirements, applicationinterfaces, multicast support, and security features and 2) the network. The Da CaPo++ system presented in this paper provides an efficient end-system middle-ware for multimedia applications, capable of handling various types of applications in a modular fashion. application needs and communication demands are specified by values in terms of QoS attributes and functional properties, such as encryption requirements or multicast support, Da CaPo++ automatically configures suitable communication protocols, provides for an efficient runtime support, and offers an easy-to-use, object-oriented application programming interface. While its applicability to real-life applications was shown by prototype implementations, performance evaluations have been carried out yielding practical experiences and numerical results.
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