The precise time integration (PTI) method is proposed to solve the linear two-point boundary value problem (TPBVP). By employing the method of dimensional expanding, the non-homogeneous ordinary differential equations...
详细信息
The precise time integration (PTI) method is proposed to solve the linear two-point boundary value problem (TPBVP). By employing the method of dimensional expanding, the non-homogeneous ordinary differential equations (ODEs) can be transformed into homogeneous ones and then the original PTI algorithms can be applied directly to the TPBVP. The PTI consists of two methods: the method of matrix exponential and the method of Riccati equations, both of which utilize the merit of 2(N) algorithm and guarantee high precise numerical results. The method of matrix exponential follows the similar scheme proposed for initial value problem of ODEs, and uses the matrix exponential to link boundary conditions between the two points. The method of Riccati equations employs the Riccati equations to express the relationships of two point boundary conditions. And then in terms of the relationships of boundary conditions at two points, the full conditions at initial point can be obtained and then the TPBVP can be transformed into initial value problem and then solved by direct time marching scheme. With some modifications, the. above algorithms can be directly extended to the infinite-interval problem and the variant coefficient ODEs problem. In the program implementation, the object-oriented (OO) design of PTI is proposed to demonstrate the applicability and easy maintenance of OO techniques in numerical computation. Finally, four selected numerical examples are given to show the high precision characteristics of PTI. (c) 2005 Elsevier Inc. All rights reserved.
As many diverse accelerator facilities are designed, constructed and operated by IMP (Institute of Modern Physics, Chinese Academy of Sciences), the existing physics control system cannot cover all requirements of the...
详细信息
As many diverse accelerator facilities are designed, constructed and operated by IMP (Institute of Modern Physics, Chinese Academy of Sciences), the existing physics control system cannot cover all requirements of these facilities. In order to save the construction time, improve the commissioning efficiency, simplify the operation and reach higher beam intensity and better beam quality, a new physics control system, PACS (Physics-oriented Accelerator Control System), is proposed, designed and implemented in the IMP. With the control layer in three layers, i.e. application layer, physics layer and control layer, the PACS is protocol neutral and can be deployed to all accelerator facilities in the IMP without massive reprogramming. The physics layer encapsulates all physics control processes, including device-level physics and system-level physics, into highly usable interfaces, which makes the development of the application layer and the customized applications simpler, more robust and efficient. Due to the OOP (object-oriented programming) technology used in this layer and specific designs, the PACS is highly scalable and can keep pace with the rapidly changing hardware and software. As the application layer is built upon the physics layer interfaces, no matter what is updated in the physics layer, the applications remain unchanged. Many new physics control processes can be tested and implemented in the physics layer by the developers or the users without influencing the operation of these facilities. Now, a version of PACS for miniature facilities is implemented and tested in the CSR, a heavy ion accelerator facility for scientific research in the IMP. It meets the expected goals and provides a solid base for following versions. In the future, the PACS will become a general-purpose physics control system for all heavy ion accelerator facilities.
Software engineering endeavours are typically based on and governed by the requirements of the target software;requirements identification is therefore an integral part of software development methodologies. Similarly...
详细信息
Software engineering endeavours are typically based on and governed by the requirements of the target software;requirements identification is therefore an integral part of software development methodologies. Similarly, engineering a software development methodology (SDM) involves the identification of the requirements of the target methodology. Methodology engineering approaches pay special attention to this issue;however, they make little use of existing methodologies as sources of insight into methodology requirements. The authors propose an iterative method for eliciting and specifying the requirements of a SDM using existing methodologies as supplementary resources. The method is performed as the analysis phase of a methodology engineering process aimed at the ultimate design and implementation of a target methodology. An initial set of requirements is first identified through analysing the characteristics of the development situation at hand and/or via delineating the general features desirable in the target methodology. These initial requirements are used as evaluation criteria;refined through iterative application to a select set of relevant methodologies. The finalised criteria highlight the qualities that the target methodology is expected to possess, and are therefore used as a basis for de. ning the final set of requirements. In an example, the authors demonstrate how the proposed elicitation process can be used for identifying the requirements of a general object-oriented SDM. Owing to its basis in knowledge gained from existing methodologies and practices, the proposed method can help methodology engineers produce a set of requirements that is not only more complete in span, but also more concrete and rigorous.
Modern mobile devices are sufficiently powerful to execute computationally intensive mathematical problems. This study presents an implementation of a two-dimensional transmission line matrix method (TLM) solver execu...
详细信息
Modern mobile devices are sufficiently powerful to execute computationally intensive mathematical problems. This study presents an implementation of a two-dimensional transmission line matrix method (TLM) solver executing on a Smartphone. Software development and architectural design are discussed, focusing on object-oriented strategies for modular and reusable code. Optimisation strategies are also discussed, with large variations in performance observed dependent on the data-caching method that is used. Swapping between data buffers using pointers was shown to be the most effective method, offering significant performance gains over the original software. It was shown for a mesh measuring 246 by 370 nodes running on an iPhone 4 that an update rate of 9.37 fps could be achieved.
In this paper, an integrated object-oriented fuzzy logic fault detection and isolation (FDI) module for a biological wastewater treatment process is presented. The defined FDI strategy and the software implementation ...
详细信息
In this paper, an integrated object-oriented fuzzy logic fault detection and isolation (FDI) module for a biological wastewater treatment process is presented. The defined FDI strategy and the software implementation are detailed. Using experimental results obtained with a one cubic meter fixed bed reactor for the anaerobic digestion of industrial wine distillery vinasses, examples of material and biological failures are presented together with the corresponding fault signals generated by the FDI module.
In object-oriented programs built in layers, an object at a higher level of abstraction is implemented by objects at lower levels of abstraction. It is usually crucial to correctness that a lower-level object not be s...
详细信息
In object-oriented programs built in layers, an object at a higher level of abstraction is implemented by objects at lower levels of abstraction. It is usually crucial to correctness that a lower-level object not be shared among several higher-level objects. This paper unveils some difficulties in writing procedure specifications strong enough to guarantee that a lower-level object can be used in the implementation of another object at a higher level of abstraction. To overcome these difficulties, the paper presents virginity, a convenient way of specifying that an object is not globally reachable and thus can safely be used in the implementation of a higher-level abstraction. (C) 1999 Elsevier Science B.V. All rights reserved.
Privacy remains a major challenge today, partly because it brings together social and technical considerations. Yet, current software engineering focuses only on the technical aspects. In contrast, the authors" a...
详细信息
Privacy remains a major challenge today, partly because it brings together social and technical considerations. Yet, current software engineering focuses only on the technical aspects. In contrast, the authors" approach, Revani, understands privacy from the standpoint of sociotechnical systems (STSs), with particular attention on the social elements of STSs. They specify STSs via a combination of technical mechanisms and social norms founded on accountability. Revani provides a way to formally represent mechanisms and norms and applies model checking to verify whether specified mechanisms and norms would satisfy stakeholder requirements. Additionally, Revani provides a set of design patterns and a revision tool to update an STS specification as necessary. The authors demonstrate the work of Revani on a healthcare emergency use case pertaining to patient privacy during disasters.
Domain-specific aspect languages (DSALs) bring the well-known advantages of domain specificity to the level of aspect code. However, DSALs incur the significant cost of implementing or extending a language processor o...
详细信息
Domain-specific aspect languages (DSALs) bring the well-known advantages of domain specificity to the level of aspect code. However, DSALs incur the significant cost of implementing or extending a language processor or weaver. Furthermore, this weaver typically operates blindly, making detection of interactions with aspects written in other languages impossible. This raises the necessity of an appropriate infrastructure for DSALs. The case study we present here illustrates how the Reflex kernel for multi-language AOP addresses these issues, by considering the implementation of a DSAL for advanced transaction management, KALA. We first detail the implementation of KALA in Reflex, called ReLAx, illustrating the ease of implementation of runtime semantics, syntax, and language translation. We then show a straightforward and modular extension to KALA at all these levels, and demonstrate how Reflex helps in dealing with interactions between KALA and another DSAL for concurrency management. These invaluable assets enable faster development of DSALs as well as their ability to coexist within one application, thereby removing the most important impediments to their re-emergence in the aspect community.
The use of object-oriented database principles to help model an image for computer vision, specifically, for line-image analysis, is described. The resulting representation, called thin line code (TLC), is general acr...
详细信息
The use of object-oriented database principles to help model an image for computer vision, specifically, for line-image analysis, is described. The resulting representation, called thin line code (TLC), is general across known applications and extensible to new applications. TLC's advantages, and also some difficulties it has in strictly adhering to traditional notions of object orientation, are addressed. A review of relevant aspects of object modeling is included
Some solutions to a programming problem are more elegant or more simple than others and thus more understandable for students. We review desirable properties of example programs from a cognitive and a measurement poin...
详细信息
Some solutions to a programming problem are more elegant or more simple than others and thus more understandable for students. We review desirable properties of example programs from a cognitive and a measurement point of view. Certain cognitive aspects of example programs are captured by common software measures, but they are not sufficient to capture a key aspect of understandability: readability. We propose and discuss a simple readability measure for software, SRES, and apply it to object-oriented textbook examples. Our results show that readability measures correlate well with human perceptions of quality. Compared with other readability measures, SRES is less sensitive to commenting and whitespace. These results also have implications for software maintainability measures.
暂无评论