Browsing by Author "Lee, CI"

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A new storage and retrieval method to support editing operations in a multi-disk-based video server
(1996)
Lee, CI
;
Chang, YI
;
Yang, WP
;
交大名義發表
;
資訊工程學系
Since the storage ordering is assumed the same ns the retrieval ordering in all the previous storage placement strategies, there is a requirement of a large amount of file copying or merging operations when users insert/delete some data into/from the media data. The observation is also important for video applications because features, like video editing, require the support of random access on individual video frames. fn this paper, roe propose a new strategy for the insert/delete operations on continuous media that are striped into multi- disks without reorganization of the whole data. From our performance analysis and simulation, the proposed algorithms for insertion/deletion may require only some additional movement cost.
Alternating hashing for expansible files
(1997-01-01)
Chang, YI
;
Lee, CI
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a generalized approach for designing a class of dynamic hashing schemes which require no index and have the growth of a file at a rate of n+1/n per full expansion, where n is the number of pages of the file, as compared to a rate of two in linear hashing. Based on this generalized approach, we derive a new dynamic hashing scheme called alternating hashing, in which, when a split occurs in page k, the data records in page k will be redistributed to page k and page (k + 1), or page k and page (k - 1), according to whether the value of level dis even or odd, respectively. (Note that a level is defined as the number of full expansions happened so far.) From our performance analysis, given a fixed load control, the proposed scheme can achieve nearly 97% storage utilization as compared to 78% storage utilization by using linear hashing.
Alternating hashing for expansible files
(1997-01-01)
Chang, YI
;
Lee, CI
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a generalized approach for designing a class of dynamic hashing schemes which require no index and have the growth of a file at a rate of n+1/n per full expansion, where n is the number of pages of the file, as compared to a rate of two in linear hashing. Based on this generalized approach, we derive a new dynamic hashing scheme called alternating hashing, in which, when a split occurs in page k, the data records in page k will be redistributed to page k and page (k + 1), or page k and page (k - 1), according to whether the value of level dis even or odd, respectively. (Note that a level is defined as the number of full expansions happened so far.) From our performance analysis, given a fixed load control, the proposed scheme can achieve nearly 97% storage utilization as compared to 78% storage utilization by using linear hashing.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
An evolutionary and attribute-oriented ensemble classifier
(2006)
Lee, CI
;
Tsai, CJ
;
Ku, CW
;
資訊工程學系
;
Department of Computer Science
In the research area of decision tree, numerous researchers have been focusing on improving the predictive accuracy. However, obvious improvement can hardly be made until the introduction of the ensemble classifier. In this paper, we propose an Evolutionary Attribute-Oriented Ensemble Classifier (EAOEC) to improve the accuracy of sub-classifiers and at the same time maintain the diversity among them. EAOEC uses the idea of evolution to choose proper attribute subset for the building of every sub-classifier. To avoid the huge computation cost for the evolution, EAOEC uses the gini value gained during the construction of a sub-tree as the evolution basis to build the next sub-tree. Eventually, EAOEC classifier uses uniform weight voting to combine all sub-classifiers and experiments show that EAOEC can efficiently improve the predictive accuracy.
Anti-control of chaos in rigid body motion
(2004-08-01)
Chen, HK
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
Anti-control of chaos for a rigid body has been studied in the paper. For certain feedback gains, a rigid body can easily generate chaotic motion. Basic dynamical behaviors, such as symmetry, invariance, dissipativity and existence of attractor, are also discussed. The transient behaviors of the chaotic system have also been presented as the feedback gain changed. Of particular interesting is the fact that the chaotic system can generate a complex multi-scroll chaotic attractor under the appropriate feedback gains. Finally, it was shown that the system could be related to the famous Lorenz equations and Chen system. In other words, the system can easily display all the dynamical behaviors of the famous Lorenz equations and Chen system. (C) 2003 Elsevier Ltd. All rights reserved.
Anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor
(2005-04-22)
Ge, ZM
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
Anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor are studied in the paper. Two different procedures for the design of the controller are proposed to anticontrol the governor system effectively. Finally, five methods are studied for chaos synchronization. (c) 2004 Elsevier Ltd. All rights reserved.
Control of particle re-entrainment by wetting the exposed surface of dust samples
(2003-10-01)
Tsai, CJ
;
Lee, CI
;
Lin, JS
;
Huang, CH
;
環境工程研究所
Experiments have been conducted in a Wind tunnel to measure the emission factor of re-entrained particles from a dry or wetted dust sample with a smooth or rough surface. Effects of wind velocities and water contents in the sample on the emission factor also were investigated. The results show that re-entrainment of particles can be controlled efficiently in a certain period of time when the surface watering density is between 60 and 80 g/m(2) at a wind velocity from 7 to 15 m/sec for both smooth and rough surfaces. After the effective period is elapsed, which depends on wind speeds and environmental conditions, water will eventually evaporate, and re-entrainment starts to occur again. The experimental water evaporation rates at different wind speeds are in good agreement with theoretical values. After watering for 210, 130, and 110 min at average wind velocities of 0, 2, and 4 m/sec, respectively, the dust sample must be replenished with water to avoid dust re-entrainment.
Control, anticontrol and synchronization of chaos for an autonomous rotational machine system with time-delay
(2005-03-01)
Ge, ZM
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
Chaos, control, anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor and spring for which time-delay effect is considered are studied in the paper. By applying numerical results, phase diagram and power spectrum are presented to observe periodic and chaotic motions. Linear feedback control and adaptive control algorithm are used to control chaos effectively. Linear and nonlinear feedback synchronization and phase synchronization for the coupled systems are presented. Finally, anticontrol of chaos for this system is also studied. (C) 2004 Elsevier Ltd. All rights reserved.
Design of a new indexing organization for a class-aggregation hierarchy in object-oriented databases
(1999-03-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In an object-oriented database, a class consists of a set of attributes, and the values of the attributes are objects that belong to other classes; that is, the definition of a class forms a class-aggregation hierarchy of classes. A branch of such a hierarchy is called a path. Several index organizations have been proposed to support object-oriented query languages, including multiindex, join index, nested index and path index. All the proposed index organizations are helpful only for a query which retrieves the objects of the root class of a given path using a predicate which specifies the value of the attribute at the end of the path. In this paper, we propose a new index organization for evaluating queries, called full index, where an index is allocated for each class and its attribute (or nested attribute) along the path. From the analysis results, we show that a full index can support any type of query along a given path with a lower retrieval cost than all the other index organizations. Moreover, to reduce the high update cost for a long given path, we split the path into several subpaths and allocate a separate index to each subpath. Given a path, the number of subpaths and the index organization of each subpath define an index configuration. Since a low retrieval cost and a low update cost are always a trade-off in index organizations, we also propose cost formulas to determine the index configuration which can provide the best performance for various applications by taking into account various types of queries along a given path and a set of queries with more than one nested predicate along a given path.
Non-linear dynamics and chaos control of a damped satellite with partially-filled liquid
(1998-11-12)
Ge, ZM
;
Lee, CI
;
Chen, HH
;
Lee, SC
;
機械工程學系
The dynamic behaviors of a damped satellite with partially-filled liquid which is subjected to external disturbance are studied in this paper. The Lyapunov direct method is used to obtain conditions of stability of the equilibrium point of the system. A co-dimension one bifurcation analysis for the autonomous system is carried out near the degenerate point. It is found that Hopf bifurcation occurs in the system by center manifold theory. By applying numerical results, phase diagrams, power spectrum, Poincare maps, and Lyapunov exponents are presented to observe periodic and chaotic motions. The effect of the parameter changes in the system can be found in the bifurcation and parametric diagrams. For global analysis, the basins of attraction of each attractor of the system are located by employing the modified interpolated cell mapping (MICM) method. Finally, several methods, the delayed feedback control, the addition of constant motor torque, the addition of periodic force, and adaptive control algorithm are used to control chaos effectively. (C) 1998 Academic Press.
Non-linear dynamics and chaos control of a damped satellite with partially-filled liquid
(1998-11-12)
Ge, ZM
;
Lee, CI
;
Chen, HH
;
Lee, SC
;
機械工程學系
The dynamic behaviors of a damped satellite with partially-filled liquid which is subjected to external disturbance are studied in this paper. The Lyapunov direct method is used to obtain conditions of stability of the equilibrium point of the system. A co-dimension one bifurcation analysis for the autonomous system is carried out near the degenerate point. It is found that Hopf bifurcation occurs in the system by center manifold theory. By applying numerical results, phase diagrams, power spectrum, Poincare maps, and Lyapunov exponents are presented to observe periodic and chaotic motions. The effect of the parameter changes in the system can be found in the bifurcation and parametric diagrams. For global analysis, the basins of attraction of each attractor of the system are located by employing the modified interpolated cell mapping (MICM) method. Finally, several methods, the delayed feedback control, the addition of constant motor torque, the addition of periodic force, and adaptive control algorithm are used to control chaos effectively. (C) 1998 Academic Press.
Non-linear dynamics and control of chaos for a rotational machine with a hexagonal centrifugal governor with a spring
(2003-05-08)
Ge, ZM
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
The dynamic behaviors of the rotational machine with a hexagonal centrifugal governor which is subjected to external disturbance are studied in the paper. The Lyapunov direct method is applied to obtain conditions of stability of the equilibrium points of system. By applying numerical results, phase diagrams, power spectrum, Poincare maps, and Lyapunov exponents are presented to observe periodic and chaotic motions. The effect of the parameter changes in the system can be found in the bifurcation and parametric diagrams. Finally, eight methods are used to control chaos effectively. (C) 2003 Elsevier Science Ltd. All rights reserved.
Reduction of particle reentrainment using porous fence in front of dust samples
(2005-12-01)
Huang, CH
;
Lee, CI
;
Tsai, CJ
;
環境工程研究所
;
Institute of Environmental Engineering
Wind tunnel experiments were conducted to measure the emission factor of particle reentrainment from a dust sample with or without a porous fence. The effect of wind velocity, fence porosity, and distance between the fence and the dust sample on the emission factor was studied. A 20% porous fence was found to be effective for reducing the particle reentrainment at a low wind velocity of 5 m/s. When the wind velocity was increase from 7 to 15 m/s, the results show that the particle reentrainment can also be reduced in a certain region behind the fence (x/H<4, x=distance between fence and sample; H=fence height) for the 20% porous fence. A linear multivariable regression model was fitted to the logarithmically transformed experimental data. The good fit of the regression model makes it possible to estimate emission rate as a function of the dimensionless distance (x/H), the wind velocity, and the elapsed time.
Regular and chaotic dynamic analysis and control of chaos for a vertically vibrating and rotating circular tube containing a particle
(2004)
Ge, ZM
;
Lee, SH
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
The paper presents the detailed nonlinear dynamic analysis of a vertically vibrating and rotating circular tube containing a particle. By adding a harmonic periodic vibration and damping force on this nonlinear system, enriched dynamic behaviors of the nonlinear system are presented. By applying the Lyapunov direct method, the conditions of stability and instability of relative equilibrium position can be determined. A codimension one bifurcation analysis for the autonomous system is carried out near the degenerate point. It is found that Hopf bifurcation occurs in the system by center manifold theory. And by applying various numerical results, such as phase portrait, Poincare map, time history and power spectrum analysis, the behaviors of the periodic and chaotic motion can be presented. The effects of the change of parameters in the system can be found in the bifurcation diagrams and parameter diagram. Further, by using Lyapunov exponents and Lyapunov dimensions we can verify the chaotic behavior. Finally, seven methods, namely, the adding of constant torque, the adding of periodic torque, the adding of impulse, delayed feedback control, adaptive control, bang-bang control, optimal control, are use to control chaos effectively to periodic orbit.