An RF channel at a cell is assigned to a call during the call set-up process. The channel is dedicated to the subscriber until the call is terminated (normal termination) or the subscriber leaves the cell (handoff). H...
详细信息
An RF channel at a cell is assigned to a call during the call set-up process. The channel is dedicated to the subscriber until the call is terminated (normal termination) or the subscriber leaves the cell (handoff). However, the RF channel may fail due to equipment failure or environment changes (failure-termination). In order to increase system end-to-end availability, an RF channel recovery method is proposed in this paper. When an RF channel fails, the channel is replaced by another working channel and the call continues. The method to replace failed RF channels of ongoing calls and to handle channel failures of handoff and new calls is investigated. The numerical results show that the recovery scheme reduces the dropped calls and the blocked calls significantly under both light and normal traffic. In addition, the numerical results for the recovery model and the pure performance model are nearly the same, which indicates that the recovery scheme can almost eliminate the dropped/blocked calls caused by channel impairment.
A fully automatic adjustment system for mass production of the optical head for magnetooptical disk drives is described. The optical head is composed of millimeter scale optical components, such as laser diode, the co...
详细信息
A fully automatic adjustment system for mass production of the optical head for magnetooptical disk drives is described. The optical head is composed of millimeter scale optical components, such as laser diode, the collimator lens, the object lens, various prisms and various detectors. A series of algorithms composed of measurement, recognition, calculation of manipulation, execution of manipulation, verification and fixation ensures proper adjustment of the head. The key is to process the measured value, recognize the shape of the beam and the waveform, and determine the manipulation. With this system, the adjustment process is reduced to 6 minutes, as compared to 9 hours it takes an experience worker.
System S is a calculus providing the basic abstractions of term rewriting: matching and building terms, term traversal, combining computations and handling failure. The calculus forms a core language for implementatio...
详细信息
This paper describes the project Quality-for-ASIS, aiming at the development of an extensive testing facility for ASIS implementations. First the specific problems and requirements are presented. After a section about...
详细信息
Re-engineering from legacy executable (binary) files is greatly facilitated by identifying and naming statically linked library functions. This paper presents an efficient method for generating files of patterns; each...
详细信息
Re-engineering from legacy executable (binary) files is greatly facilitated by identifying and naming statically linked library functions. This paper presents an efficient method for generating files of patterns; each pattern is a transformation of the first several bytes of a library function's executable code. Given a suitable pattern file, a candidate function can be identified in linear time. One pattern file is generated for each combination of compiler vendor, version and memory model (where applicable). The process of identifying these parameters in a given executable file also identifies the main function of the program, i.e. the start of the code written by the user. The pattern files are produced automatically from a compiler's library file in a few seconds, with no user intervention required. Due to various limitations, not all library functions can be identified correctly; a small number will be either incorrectly identified or not identified. Optimal perfect hash functions are used to keep the pattern files compact and efficient to process.
Spot noise and line integral convolution (LIC) are two texture synthesis techniques for vector field visualization. The two techniques are compared. Continuous directional convolution is used as a common basis for com...
详细信息
Spot noise and line integral convolution (LIC) are two texture synthesis techniques for vector field visualization. The two techniques are compared. Continuous directional convolution is used as a common basis for comparing the techniques. It is shown that the techniques are based on the same mathematical concept. Comparisons of the visual appearance of the output and performance of the algorithms are made.
In this paper the motivation, design and application of a distributed blackboard architecture for interactive data visualization is discussed. The main advantages of the architecture are twofold. First, it allows visu...
详细信息
In this paper the motivation, design and application of a distributed blackboard architecture for interactive data visualization is discussed. The main advantages of the architecture are twofold. First, it allows visualization tools to be tightly integrated with simulations. Second, it allows qualitative and quantitative analysis to be combined during the visualization process.
A workflow history manager maintains the information essential for workflow monitoring and data mining as well as for recovery and authorization purposes. Certain characteristics of workflow systems like the necessity...
A workflow history manager maintains the information essential for workflow monitoring and data mining as well as for recovery and authorization purposes. Certain characteristics of workflow systems like the necessity to run these systems on heterogeneous, autonomous and distributed environments and the nature of data, prevent history management in workflows to be handled by the classical data management techniques like distributed DBMSs. We further demonstrate that multi-database query processing techniques are also not appropriate for the problem at hand. In this paper, we describe history management, i.e., the structure of the history and querying of the history, in a fully distributed workflow architecture realized in conformance with Object Management Architecture (OMA) of OMG. By fully distributed architecture we mean that the scheduler of the workflow system is distributed and in accordance with this, the history objects related with activities are stored on data repositories (like DBMSs, files) available at the sites involved. We describe the structure of the history objects determined according to the nature of the data and the processing needs, and the possible query processing strategies on these objects using the Object Query Service of OMG. We then present the comparison of these strategies according to a cost model developed.
The COCOMO II model was created to meet the need for a cost model that accounted for future software development practices. This paper describes some of the experiences learned in calibrating COCOMO II Post-Architectu...
详细信息
The COCOMO II model was created to meet the need for a cost model that accounted for future software development practices. This paper describes some of the experiences learned in calibrating COCOMO II Post-Architecture model from eighty-three observations. The results of the multiple regression analysis, their implications, and a future calibration strategy are discussed.
System S is a calculus providing the basic abstractions of term rewriting: matching and building terms, term traversal, combining computations and handling failure. The calculus forms a core language for implementatio...
System S is a calculus providing the basic abstractions of term rewriting: matching and building terms, term traversal, combining computations and handling failure. The calculus forms a core language for implementation of a wide variety of rewriting languages, or more generally, languages for specifying tree transformations. In this paper we show how a conventional rewriting language based on conditional term rewriting can be implemented straightforwardly in System S. Subsequently we show how this implementation can be extended with features such as matching conditions, negative conditions, default rules, non-strictness annotations and alternative evaluation strategies. We thank Bas Luttik and Andrew Tolmach for many discussions on rewriting strategies and their applications. Jan Bergstra pointed out the problems of non-determinism and conditional rules in languages such as ASF+SDF. Eu-genio Moggi made clear that our semantics does not model programs with global backtracking, but rather local backtracking, which was what we were looking for.
暂无评论