Hardware-software co-design is the simultaneous design of the software which implements a set of functions and the hardware platform on which the software executes. Co-design is often necessary in the design of embedd...
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Hardware-software co-design is the simultaneous design of the software which implements a set of functions and the hardware platform on which the software executes. Co-design is often necessary in the design of embedded systems to meet their performance and cost requirements. In most embedded systems, some implementation choices are easily predictable while others are not. Existing specification methodologies have not considered by the necessary uncertainty of the implementation of critical functions. object-oriented specification techniques are, however, well-suited to the partitioning of concerns necessary for co-specification. This paper presents some techniques for adapting object-oriented specification to co-specification and illustrates their use with an example.
In agriculture as in other domains, there exists a need for multifaceted and comprehensive decision support frameworks enabling the integration and use of different types of knowledge and information processing tools....
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In agriculture as in other domains, there exists a need for multifaceted and comprehensive decision support frameworks enabling the integration and use of different types of knowledge and information processing tools. The object-oriented paradigm provides a foundation for the construction of such general decision support frameworks. The objective of the described project was to build an object-oriented framework (called SAGE) for knowledge management and decision support in the area of agro-ecosystem management. The Smalltalk object-oriented programming system was the basic technology used to build the SAGE system. A Smalltalk-based object-oriented database management system was also used to provide persistence for Smalltalk objects. The result of the design and implementation effort is a library of Smalltalk classes that constitutes a framework onto which developers can build systems to represent agroecosystems and support the management of these systems. These classes are described and their design and implementation issues are discussed.
Scientific programmers are eager to take advantage of the computational power offered by Distributed Computing systems (DCSs) but are generally reluctant to undertake the porting of their application programs onto suc...
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Scientific programmers are eager to take advantage of the computational power offered by Distributed Computing systems (DCSs) but are generally reluctant to undertake the porting of their application programs onto such machines. The DCSs commercially available today are indeed widely believed to be difficult to use, which should not be a surprise because they are traditionally programmed with software tools dating back to the days of punch cards and paper tape. We claim that, provided modern object-oriented technologies are used, these computers can be programmed easily and efficiently. We propose a framework where the tricky parallel codes can be encapsulated in object-oriented software components that can be reused, combined, and customized in confidence by application programmers. We propose to use a kind of parallelism known as data-parallelism, encapsulated within classes of a purely sequential object-oriented language (Eiffel), using the SPMD (Single Program Multiple Data) programming model. We define a set of methodological rules to help a programmer design and exploit parallel software components within this framework. We illustrate our approach with the example of PALADIN, an object-oriented library devoted to linear algebra computation on DCSs. PALADIN relies on widely advertised object-oriented features to help a numerical programmer develop or parallelize application programs, following the guidelines of modern software engineering. Most notably, modularity and encapsulation are used to hide data distribution and code parallelization within classes presenting sequential interfaces, while inheritance allows a transparent reuse of basic parallel patterns in new applications. We discuss the implementation of a demonstrator of such a library as well as performance related aspects.
The timetabling problem has traditionally been treated as a mathematical optimization, heuristic, or human-machine interactive problem. These approaches tend to suffer from lack of flexibility, computational intractab...
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The timetabling problem has traditionally been treated as a mathematical optimization, heuristic, or human-machine interactive problem. These approaches tend to suffer from lack of flexibility, computational intractability, and poor results. We introduce an automated timetabler that combines data, model and knowledge-bases, developed using object-oriented methodology. The inclusion of expert knowledge allows for solutions that fit the problem context better while the use of a database enables a more flexible and maintainable system. The object-oriented paradigm allows for a more efficient design and code implementation of scheduling procedures. Results have been promising as the system has automatically scheduled over 2000 students and instructors into more than 300 classes.
A major complexity in the development of many computerized information systems is the lack of an integrated framework and analysis structure to consolidate disparate types of information. Successful information system...
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A major complexity in the development of many computerized information systems is the lack of an integrated framework and analysis structure to consolidate disparate types of information. Successful information system development in complex environments requires an approach that supports development of systems across all information areas and uses the same model for analysis, specification, prototyping, design and implementation. This paper presents a robust methodology for dealing with these needs. The method has a sound theoretical basis, yet is straightforward to understand and use. An application from computerized manufacturing is used to illustrate the method.
Communication behavior represents dynamic evolution and cooperation of a group of objects in accomplishing a task. It is an important feature in object-orientedsystems. We propose the concept of activity as a basic b...
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Communication behavior represents dynamic evolution and cooperation of a group of objects in accomplishing a task. It is an important feature in object-orientedsystems. We propose the concept of activity as a basic building block for declarative specification of communication behavior in object-oriented database systems, including the temporal ordering of message exchanges within object communication and the behavioral relationships between activity executions. We formally introduce two kinds of activity composition mechanisms: activity specialization and activity aggregation for abstract implementation of communication behavior. The former is suited for behavioral refinement of existing activities into specialized activities. The latter is used for behavioral composition of simpler activities into complex activities, and ultimately, into the envisaged database system. We use first-order temporal logic as an underlying formalism for specification of communication constraints. The well-known Air-traffic-control case is used as a running example to highlight the underlying concepts, to illustrate the usefulness, and to assess the effectiveness of the activity model for declarative specification of communication behavior in the relevant universe of discourse. We also propose a methodological framework for integrating activity schema with entity schema in an object-orienteddesign environment.
The article defines the object-orienteddesign patterns. It also describes the initial steps to introduce patterns to Phoenix, Arizona-based AG Communication systems Inc. through training by the Dalmatian Group Inc. E...
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The article defines the object-orienteddesign patterns. It also describes the initial steps to introduce patterns to Phoenix, Arizona-based AG Communication systems Inc. through training by the Dalmatian Group Inc. Each pattern describes a problem that occurs over and over again in our environment and then describes the core of the solution to that problem in such a way that you can use this solution a million times over without ever doing it the same way twice. design patterns capture the static and dynamic structures of solutions that occur repeatedly when producing applications in a particular context. The firm organized evaluation meetings that were open to anyone interested in learning about patterns. That provided a larger audience for the information and more input for the discussions. The patterns sell themselves. Training in these patterns should be provided for teams to enhance communication and design knowledge. Some members of the team expressed concern with the lack of real-time, embedded system considerations in design Patterns. This was addressed in the training through the use of additional examples and implementation details lacking in the book.
A ''separable'' approach to the object-orienteddesign of modeling systems is presented. In it, the local behavior of an individual object is separated from the global behavior of the system, and the f...
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A ''separable'' approach to the object-orienteddesign of modeling systems is presented. In it, the local behavior of an individual object is separated from the global behavior of the system, and the functional decomposition of the system is separated from its synthesis as a set of interacting objects-entities that encapsulate data and behavior. In a pipe network, elements such as pipes, junctions, pumps, and valves can be represented in the form of objects (so-called agents) encapsulating specific attributes and the behavior of each element. The behavior of the network as a whole is encapsulated in an object that controls agents (so-called actor). This approach is demonstrated in the design and implementation of an interactive water distribution modeling and design system, the hydraulic modeling system (HIS):, an example of its application is given. The use of object orientation in constructing computer-based models Is viewed as very promising in the field of hydraulic and environmental modeling, and especially in relation to promoting computer code reusability and model flexibility.
Mesh generation and adaption for solving dopant diffusion in process simulation is a difficult task, complicated by both the moving boundaries of oxide growth [1] and the time dependence of the solutions. For both com...
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Mesh generation and adaption for solving dopant diffusion in process simulation is a difficult task, complicated by both the moving boundaries of oxide growth [1] and the time dependence of the solutions. For both computational and ease of use reasons, automatic mesh generation [2] and discretization error control [3] is desirable. This paper describes an approach based on local error estimates [4] to refine the mesh. The results presented in this paper extend our previous work [5] to two-dimensional problems. The implementation of this approach is done in a process simulator, the Florida object-oriented Process Simulator. Several test cases are described to demonstrate the effectiveness of the algorithms.
A graphical 'front end' using the freely available Tcl/Tk programming toolkit is used to provide a point and click and drag and drop interface to the users of interface to Matlab. The overall effect is an intu...
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A graphical 'front end' using the freely available Tcl/Tk programming toolkit is used to provide a point and click and drag and drop interface to the users of interface to Matlab. The overall effect is an intuitive and easy to use interface to Matlab which may also be utilized to provide the same structure to a similar tool with only minor code changes. The implementation of the drag and drop philosophy projects an objectoriented window onto the underlying application providing significant gains in learning and productivity.
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