This paper reports on an on-going project undertaken within the University of Rome at Tor Vergata to automate the business processes of a class of administrative organizations. The experience gained and the lessons le...
The suffix array is a string-indexing structure and a memory efficient alternative to the suffix tree. It has many advantages for text processing. We propose an efficient algorithm for sorting suffixes. We call this a...
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The suffix array is a string-indexing structure and a memory efficient alternative to the suffix tree. It has many advantages for text processing. We propose an efficient algorithm for sorting suffixes. We call this a...
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The suffix array is a string-indexing structure and a memory efficient alternative to the suffix tree. It has many advantages for text processing. We propose an efficient algorithm for sorting suffixes. We call this algorithm the two-stage suffix sort. One of our ideas is to exploit the specific relationships between adjacent suffixes. Our algorithm makes it possible to use the suffix array for much larger texts and suggests new areas of application. Our experiments on several text data sets (including 514-MB Japanese newspapers) demonstrate that our algorithm is 4.5 to 6.9 times faster than Quicksort, and 2.5 to 3.6 times faster than K. Sadakane's (1998) algorithm, which is considered to be the fastest algorithm in previous work.
The LMS algorithm forms the core of a number of adaptive control schemes. It has on one hand provided certain degree of robustness to these algorithms but on the other hand its convergence rate is notoriously slow. We...
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The LMS algorithm forms the core of a number of adaptive control schemes. It has on one hand provided certain degree of robustness to these algorithms but on the other hand its convergence rate is notoriously slow. We propose a method to initialize the LMS algorithm which dramatically shortens its adaptation period. We also prove that under certain condition this initialization can be computed without explicit knowledge of either the reference or noise spectrum. Although the work is illustrated using the filtered-X scheme, this idea can also be applied to other similar schemes. Two successful experiments starting from black-box identification to real-time control have verified the effectiveness of this idea.
This paper considers an optimization problem of a 3-dimensional truss whose vibration is controlled in the case of sensor/actuator collocation. The design variables are cross sectional areas of truss members and locat...
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This paper considers an optimization problem of a 3-dimensional truss whose vibration is controlled in the case of sensor/actuator collocation. The design variables are cross sectional areas of truss members and locations of the collocated sensors/actuators. The problem has three objectives, the structural weight, the function that represents the influence of the initial state of the system and the number of sensors/actuators. By minimizing the second objective, we can suppress the vibration to some degree. Moreover, in this paper, we consider the uncertainty of the initial state of the system which is dependent on the initial loading conditions. We treat these three objectives by the weighing method for multiobjective problem. The optimization is carried out by the use of Genetic Algorithm. It is shown through numerical simulation that the improvement of the vibration suppression is accomplished by the small control input for the structure designed by the present formulation.
The paper describes a subject called softwareengineering Practise, which introduces softwareengineering concepts to students in a generalist computing degree. The course has three aims: to establish a foundation of ...
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The paper describes a subject called softwareengineering Practise, which introduces softwareengineering concepts to students in a generalist computing degree. The course has three aims: to establish a foundation of good practice which will form the basis for a personal software improvement process in subsequent studies and in professional life; to introduce object oriented design in a context firmly embedded in softwareengineering; and to give students a taste of working in groups on a reasonably large project. The success of this course is due to the way in which the object oriented design, the softwareengineering process aspects and the project work so well together to bring the concepts associated with each part of the course to life and to reinforce each other in a relatively realistic context. Other aspects, which contribute to the success of the course, such as the team approach to course management, individual student assessment, and choice of development environment, are also highlighted.
Concurrency and communication are two of the key features of distributed systems. These features can make systematic testing of distributed systems a complex task. A major problem is the explosion of the test space be...
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Concurrency and communication are two of the key features of distributed systems. These features can make systematic testing of distributed systems a complex task. A major problem is the explosion of the test space because of the potential for arbitrary interference of concurrent threads. This paper describes an approach for systematic testing of such systems in an object-oriented context. We use statecharts for system specification, and model the system behaviour as event-sequences. A test case, therefore, is primarily an event-sequence with concurrent threads represented as interleaving events. Communication-states with associated events represent communication between objects. The test-space explosion is controlled by an extension to Chow's (1978) algorithm for generating test sequences for finite state machines. The number of test sequences we require is O(n/sup 2/), where n is the sum of all events in all concurrent statecharts.
In this paper we address the decomposition problem of electromyographic signals (EMG) and we present a new idea for the decomposition approach introducing the time-scale phase representation. Considering the nature of...
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In this paper we address the decomposition problem of electromyographic signals (EMG) and we present a new idea for the decomposition approach introducing the time-scale phase representation. Considering the nature of EMG signals, a special set of nonorthogonal conjugated basis functions is used to perform the time-scale analysis. Mapping the modified signal phase into the time-scale phase plane is applied. Its minimization leads towards a very good time localization of individual superimposed signal components.
Object-orientation has rapidly become accepted as the preferred paradigm for large scale system design. There is considerable literature describing approaches to object-oriented design and implementation. However disc...
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Object-orientation has rapidly become accepted as the preferred paradigm for large scale system design. There is considerable literature describing approaches to object-oriented design and implementation. However discussion of testing in an object-oriented environment has been conspicuous by its absence. At first sight it appears that decomposition of a system into a potentially large number of information-hiding classes greatly increases the cost of testing. However in this paper we show that by taking an object-oriented approach to testing, and the inclusion of appropriate tools in the development environment, testing time can be greatly reduced and special purpose test code can be virtually eliminated.
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