Object abstraction supports the separation of what operations are provided by systems and components from how the operations are implemented, and is essential in enabling the construction of complex systems from compo...
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ISBN:
(纸本)9781595930316
Object abstraction supports the separation of what operations are provided by systems and components from how the operations are implemented, and is essential in enabling the construction of complex systems from components. Unfortunately, clear and modular implementations have poor performance when expensive query operations are repeated, while efficient implementations that incrementally maintain these query results are much more difficult to develop and to understand, because the code blows up significantly, and is no longer clear or *** paper describes a powerful and systematic method that first allows the "what" of each component to be specified in a clear and modular fashion and implemented straightforwardly in an object-oriented language; then analyzes the queries and updates, across object abstraction, in the straightforward implementation; and finally derives the sophisticated and efficient "how" of each component by incrementally maintaining the results of repeated expensive queries with respect to updates to their parameters. Our implementation and experimental results for example applications in query optimization, role-based access control, etc. demonstrate the effectiveness and benefit of the method.
The approaches and methods for further development of applied theory of systems with distributed parameters are suggested to solve problems of open-loop controllability, construction of program optimization, a wide ra...
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The approaches and methods for further development of applied theory of systems with distributed parameters are suggested to solve problems of open-loop controllability, construction of program optimization, a wide range of vector problems of optimal control and analytical designing of automatic regulators.
To solve the complex problems of Multi-Thread programing,a frame of the model of Java Actor used to implement uJavaActor is *** startup speed,responding speed in long time running,and the average running time of the s...
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ISBN:
(纸本)9781509011964
To solve the complex problems of Multi-Thread programing,a frame of the model of Java Actor used to implement uJavaActor is *** startup speed,responding speed in long time running,and the average running time of the system are accelerated by the improvements of Thread pool,Java lock and concurrent data structure in uJavaActor *** uJavaActor improved is compared in runtime contrast with the original frame in the area about the running speed of implementing the model of *** analyzing the running results,the frame improved consists of higher startup speed,shorter running time,and faster reaction after receiving new tasks,which proves that the total running speed of the uJavaActor model is boosted efficaciously with the improvements in such two areas.
Object-relational mapping libraries are a popular way for applications to interact with databases because they provide transparent access to the database using the same language as the application. Unfortunately, usin...
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ISBN:
(纸本)9781450320146
Object-relational mapping libraries are a popular way for applications to interact with databases because they provide transparent access to the database using the same language as the application. Unfortunately, using such frameworks often leads to poor performance, as modularity concerns encourage developers to implement relational operations in application code. Such application code does not take advantage of the optimized relational implementations that database systems provide, such as efficient implementations of joins or push down of selection predicates. In this paper we present QBS, a system that automatically transforms fragments of application logic into SQL queries. QBS differs from traditional compiler optimizations as it relies on synthesis technology to generate invariants and postconditions for a code fragment. The postconditions and invariants are expressed using a new theory of ordered relations that allows us to reason precisely about both the contents and order of the records produced complex code fragments that compute joins and aggregates. The theory is close in expressiveness to SQL, so the synthesized postconditions can be readily translated to SQL queries. Using 75 code fragments automatically extracted from over 120k lines of open-source code written using the Java Hibernate ORM, we demonstrate that our approach can convert a variety of imperative constructs into relational specifications and significantly improve application performance asymptotically by orders of magnitude.
Aiming at the shortcoming of paying attention only to the combat performance and life cycle cost(LCC)during evaluating development plan of weapon systems,this paper establishes evaluation indicators of general perform...
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Aiming at the shortcoming of paying attention only to the combat performance and life cycle cost(LCC)during evaluating development plan of weapon systems,this paper establishes evaluation indicators of general performance of weapon systems,and uses grey interrelated an alysis method to evaluate and *** paper also brings forward a new weight determination method based on Euclidean Distance to improve it on the basis of analyzing the defects of classic grey interrelated analysis method,which avoids Subjective factors and makes the evaluation results more objective and *** through an example in the practice of development project of defense equipment,the method's specific applications are introduced and the feasibility and effectiveness of this method verified.
The global data relationships in a program can be exposed and codified by the static analysis methods described in this paper. A procedure is given which determines all the definitions which can possibly “reach” eac...
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It's essential to improve the running performance of programs to reveal Java platform-independence and distributed computing advantages, and to accelerate the web technology. This paper discusses the byte code spe...
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It's essential to improve the running performance of programs to reveal Java platform-independence and distributed computing advantages, and to accelerate the web technology. This paper discusses the byte code specialization technology based on partial evaluation and presents the mechanism of specializing general program codes to the efficient implementation aimed at the specific area and architecture. A partial evaluator Jmix oriented-Java byte code is realized and the performance results show that Jmix abbreviates the byte code and enhances the running efficiency.
The use of supercomputing technology, parallel and distributed processing, and sophisticated algorithms is of major importance for computational scientists. Yet, the scientists’ goals are to solve their challenging s...
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The use of supercomputing technology, parallel and distributed processing, and sophisticated algorithms is of major importance for computational scientists. Yet, the scientists’ goals are to solve their challenging scientific problems, not the software engineering tasks associated with it. For that reason, computational science and engineering must be able to rely on dedicated support from program development and analysis tools. The primary intention of this workshop is to bring together developers of tools for scientific computing and their potential users. Tool developers present how their tools support scientists and engineers during program development and analysis. The users report their experiences employing such tools, especially highlighting the benefits and possible improvements.
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