Browsing by Author "Chen, JY"

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A behavior-based classification and retrieval technique for object-oriented specification reuse
(1996-07-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
This paper presents a classification and retrieval technique for object-oriented specification reuse, based on the assumption that existing specifications exhibiting behaviors similar to that of the system under development are appropriate for reuse. Existing specifications are classified and retrieved according to the semantic networks abstracted from their behaviors. Since semantic networks attach semantic meanings to certain degrees of detail, our technique is rather precise. Primary behavior is used to classify specifications because it can be obtained in the early phases of system analysis. Therefore, our technique allows early reuse. Moreover, subspecifications and classes of existing specifications are classified independently so that they can be retrieved for reuse separately. Thus, our technique encourages reusing subspecifications as well as classes. Since a subspecification is composed of classes and their relationships, reusing it corresponds to reusing all those classes and relationships, A technique that reuses subspecifications as well as classes is thus expected to save more time than those that reuse only classes.
A behavior-based classification and retrieval technique for object-oriented specification reuse
(1996-07-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
交大名義發表
;
資訊工程學系
This paper presents a classification and retrieval technique for object-oriented specification reuse, based on the assumption that existing specifications exhibiting behaviors similar to that of the system under development are appropriate for reuse. Existing specifications are classified and retrieved according to the semantic networks abstracted from their behaviors. Since semantic networks attach semantic meanings to certain degrees of detail, our technique is rather precise. Primary behavior is used to classify specifications because it can be obtained in the early phases of system analysis. Therefore, our technique allows early reuse. Moreover, subspecifications and classes of existing specifications are classified independently so that they can be retrieved for reuse separately. Thus, our technique encourages reusing subspecifications as well as classes. Since a subspecification is composed of classes and their relationships, reusing it corresponds to reusing all those classes and relationships, A technique that reuses subspecifications as well as classes is thus expected to save more time than those that reuse only classes.
A collision resolution paradigm for Random Access Channel control in multi-access wireless networks
(2002)
Yuang, MC
;
Lo, BC
;
Chen, JY
;
資訊工程學系
;
Department of Computer Science
The Random Access Channel (RACH) incurs a collision if more than one user make signaling requests over the same time slot, spreading code, or antenna element, in TDMA, CDMA, or SDMA wireless networks, respectively. In this paper, we propose a Hexanary-Feedback Collision Resolution Paradigm (HFCRP), capable of leveraging access efficiency of the RACH for all above wireless networks. HFCRP performs incremental contention resolution, managing a small subset of users at a time via a two-phase process. In the first phase, a group of users is probabilistically admitted, with a negligible probability of the group size greater than five. In the second phase, all users in the group are efficiently resolved. The two-phase process is augmented with hexanary feedback control facilitated by an nvelope-pdf-based Multi-user stimator ( M R) implemented at the physical layer. significantly, the M R measures the exact number of transmitting users (zero to five) in a contention slot by matching the envelope pdf s histograms of received signals to a library of pre-constructed pdf s. These six outcomes comprise the hexanary feedback being broadcast to users during the real-time operation of the two-phase process. Analytic and simulation results delineate that, performing in con unction with the M R, HFCRP achieves high performance with respect to maximum stable throughput, saturated throughput, access delay, and blocking probability.
A perfectly stable contention access scheme for wireless access networks
(2001)
Yuang, MC
;
Lo, BC
;
Chen, JY
;
資訊工程學系
;
Department of Computer Science
Existing TDM-based contention access schemes exhibit the unstable or load-susceptible problem in which throughput exponentially deteriorates as the traffic offered load increases or fluctuates. In this paper, we propose a persistently stable, efficient Hexanary-Feedback-based Contention Access (HFCA) scheme, aiming to provide QoS guarantee while retaining stable and maximal network throughput. Unlike existing schemes that consider all contending mobile terminals as a whole, HFCA incrementally resolves a small group of terminals each time via a two-phase selection/resolution process. The incremental resolution repeats until the minimum non-blocking probability (QoS for signaling traffic) is satisfied. To accelerate resolution within the process, the number of simultaneously transmitting terminals is estimated based on an Envelope-pdf-based Estimator (EPER), by matching the corresponding normalized envelope histogram of the receiving signal with the priori envelope-pdf library. Facilitated with incremental resolution and the EPER, HFCA achieves the highest maximum throughput (0.574) and saturated throughput (0.52) reported to date irrespective of traffic increase and variation.
Alkylation of nanoporous silica thin films by high density plasma chemical vapor deposition of a-SIC : H
(2004-05-01)
Pan, FM
;
Wu, BW
;
Cho, AT
;
Tsai, KC
;
Tsai, TG
Film stacks of a-SiC:H and molecularly templated nanoporous silica thin films have been prepared, and alkylation of pore surfaces of the nanoporous silica layer by the a-SiC:H layer was studied. The a-SiC:H thin films were deposited by high-density plasma chemical vapor deposition (HDP-CVD) using trimethylsilane (3MS) as the precursor. Carbon is found to uniformly distribute in the thin nanoporous silica film, and the carbon content in the nanoporous film decreases with increasing the a-SiC:H deposition temperature. We used the modified Sanderson formalism to estimate the corresponding Si(2p) and C(1s) electron energies in x-ray photoelectron spectra (XPS) for possible terminal species on pore surfaces in the nanoporous silica layer. According to the XPS analysis and thermal desorption mass spectroscopy, the terminal species are probably in the chemical form of alkoxyl structures. The alkoxyl terminal groups introduced into the nanoporous silica thin film are believed to stem from hydrocarbons trapped in microvoids in the a-SiC:H film, which are formed during the HDP-CVD deposition. The terminal alkoxyl groups in the nanoporous silica layer can greatly enhance the hydrophobicity of the nanoporous silica dielectric, and hence improve the dielectric property of the film stack of a-SiC:H/nanoporous silica. An effective dielectric constant smaller than 1.7 can be obtained for the film stacks. (C) 2004 American Vacuum Society.
An activity-based predicate/transition net model of operational control planning for a flexible manufacturing system
(2004-04-01)
Hsu, HP
;
Chen, JY
;
Su, CT
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
An effective flexible manufacturing system (FMS) relies on a hierarchy of decisions, including the control of the FMS operation. The FMS operation usually is dynamically constrained by the limited resources such as pallets, machines, tools, carts, etc. Most analytical models make many assumptions and oversimplify the complicated decision problems. This study proposes the predicate/transition (Pr/Tr) net, a high level petri net, as a model for operational control planning. Firstly, the activities (modes) and their resources usage in FMS were analysed and aggregated into activity sets. Then, the flow of parts among activities was traced to obtain the "mode transition diagram", and then the Pr/Tr net model was introduced. We incrementally defined the predicates and transitions into this model. Finally, a comprehensive FMS Pr/Tr net model was derived. By implementing it into a rule-based simulation model, it is well suited for FMS operational control planning because of its inclusiveness and high flexibility.
An executable specification language for specification understanding in object-oriented specification reuse
(1996-06-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
System analysis time can be reduced through specification reuse which, however, requires specification understanding. This paper presents an object-oriented executable specification language which reduces understanding time through executing specifications. In addition to being executable, the specification language hides as many classes as possible within subsystems, and explicitly specifies relationships between specification components. This facilitates specification modification. Moreover, the language explicitly specifies interface parameters of specification components. This facilitates specification composition.
An executable specification language for specification understanding in object-oriented specification reuse
(1996-06-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
System analysis time can be reduced through specification reuse which, however, requires specification understanding. This paper presents an object-oriented executable specification language which reduces understanding time through executing specifications. In addition to being executable, the specification language hides as many classes as possible within subsystems, and explicitly specifies relationships between specification components. This facilitates specification modification. Moreover, the language explicitly specifies interface parameters of specification components. This facilitates specification composition.
Carrier-to-interference ratio measurement using moments or histograms
(2000-08-01)
Su, YT
;
Chen, JY
;
電信工程研究所
;
Institute of Communications Engineering
Cochannel interference is often the predominant factor that limits the capacity of a cellular mobile radio system. Power control is thus needed so that carrier-to-cochannel interference ratio (CIR) can be maintained within a tolerable bound. Many power control algorithms that require real-time CIR measurement have been proposed but there is very few mentioning of the measurement method, This paper presents viable solutions for real-time CIR estimations under various channel conditions. These solutions are based on either the method of moments or the histogram matching concept. We provide numerical results to demonstrate the usefulness and to compare the performance of the proposed algorithms. It is found that the histogram matching method with a properly-designed nonuniform quantizer offers excellent CIR estimation.
Data mining application in customer relationship management of credit card business
(2005)
Wu, RC
;
Chen, RS
;
Chang, CC
;
Chen, JY
;
資訊管理與財務金融系註：原資管所+財金所
First, we classify the selected customers into clusters using RFM model to identify high-profit, gold customers. Subsequently, we carry out data mining using association rules algorithm. We measure the similarity, difference and modified difference of mined association rules based on three rules, i.e. Emerging Patten Rule, Unexpected Change Rule, and Added/Perished Rule. In the meantime, we use rule matching threshold to derive all types of rules and explore the rules with significant change based on the degree of change measured. In this paper, we employ data mining tools and effectively discover the current spending pattern of customers and trends of behavioral change, which will allow management to detect in a large database potential changes of customer preference, and provide as early as possible products and services desired by the customers to expand the clientele base and prevent customer attrition.
Effect of trimethylsilylation on the film stress of mesoporous silica ultralow-k film stacks
(2006)
Chen, JY
;
Pan, FM
;
Lin, DX
;
Cho, AT
;
Chao, KJ
The film stress of the ultralow-k mesoporous silica thin film and the alpha-SiC:H/ mesoporous silica film stack was studied. The as-calcined mesoporous silica exhibits a tensile film stress due to its volume contraction during bake and calcination. Trimethylsilylation of the mesoporous film results in a spring-back effect and thereby improves the mechanical properties of the porous film. Deposition of a plasma-assisted alpha-SiC:H layer on the mesoporous silica thin film can also relieve the tensile stress, and even made the film stack become compressively stressed. This is ascribed to the stress compensation and alkoxylation occurring during the alpha-SiC:H deposition.
Effects of metal-doped indium-tin-oxide buffer layers in organic light-emitting devices
(2006-06-01)
Chen, TH
;
Wu, TJ
;
Chen, JY
;
Liou, Y
;
顯示科技研究所
Organic light-emitting devices were fabricated by using different metal (V, Zr, Hf)-doped indium-tin-oxide (ITO) buffer layers on an ITO anode. The metal-doped ITO buffer layers were 15 nm thick with different metal concentrations. Both resistivity and work function of the ITO buffer layer were manipulated by these metal dopants. Different effects on the devices, such as reduced turn-on voltage, improved luminance, and enhanced current efficiency, were investigated. A low turn-on voltage was observed for devices with small work function and resistivity. The lowest turn-on voltage (3 V) was found on a device with a V-doped ITO buffer layer. The devices usually have a similar current density (J)-voltage (V) characteristics, but not the luminance-J or the current efficiency-J characteristics when the ITO buffer layers have the same work function. The devices with the Hf-doped ITO buffer layers show the best luminance performance among those considered. At 100 mA/cm(2), a luminance of 15,000 cd/m(2), and a current efficiency of 15 cd/A have been achieved. The balance between the carrier concentration and the energy barrier for the hole injection is possibly responsible for such performance.
Estimation of number of people in crowded scenes using perspective transformation
(2001-11-01)
Lin, SF
;
Chen, JY
;
Chao, HX
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In the past, the estimation of crowd density has become an important topic in the field of automatic surveillance systems. In this paper, the developed system goes one step further to estimate the number of people in crowded scenes in a complex background by using a single image. Therefore, more valuable information than crowd density can be obtained. There are two major steps in this system: recognition of the head-like contour and estimation of crowd size. First, the Haar wavelet transform (HWT) is used to extract the featured area of the bead-like contour, and then the support vector machine (SVM) is used to classify these featured area as the contour of a head or not. Next, the perspective transforming technique of computer vision is used to estimate crowd size more accurately. Finally, a model world is constructed to test this proposed system and the system is also applied for real-world images.
Hexanary-feedback contention access with PDF-based multiuser estimation for wireless access networks
(2004-01-01)
Yuang, MC
;
Lo, BC
;
Chen, JY
;
資訊工程學系
;
Department of Computer Science
Most existing contention access schemes are inherently unstable resulting in exponentially deteriorating throughput under increased traffic loads. In this paper, we propose a wide-sense stable (WSS) efficient hexanary-feedback contention access (HFCA) scheme, capable of providing signaling traffic high performance while retaining maximal throughput for wireless access networks. HFCA performs incremental contention resolution, managing a small subset of users at a time via a two-phase process. In the first phase, a group of users is probabilistically admitted, with a negligible probability of the group size greater than five. In the second phase, all users in the group are efficiently resolved. The two-phase process is augmented with hexanary feedback control facilitated by a probability density function (pdf)-based multiuser estimator (PMER) implemented at the physical layer. Basically, PMER measures the exact number of transmitting users (zero to five) in a contention slot by matching the envelope-phase pdf's histograms of received signals to a preconstructed pdf's library. To formally justify the performance of HFCA, we present throughput and stability analysis in which HFCA is shown WSS and the strict-sense stability condition is derived. Finally, analytic and simulation results delineate that, HFCA is highly robust against estimation discrepancy. Significantly, HFCA achieves high performance with respect to maximum stable and saturated throughputs, access delay, and blocking probability.
Liquid-crystal-based tunable optical filtering devices for DWDM
(2001)
Pan, RP
;
Tung, XX
;
Chen, JY
;
Huang, MJ
;
Pan, CL
We report a new configuration of tunable optical filter for DWDM applications. In this design, first-order diffracted signal light by a grating is directed to a lens and focused on to a transmission-type liquid crystal spatial light modulator (LC-SLM). Wavelength channels are selected by opening the appropriate pixels of the LC-SLM for transmission. The device is demonstrated by using a broad-band AR-coated laser diode (lamda = 800 nm) as the signal light. For conceptual demonstration, we use optical fibers with a core diameter of 50 microns instead of the LC-SLM. A total of 37 channels, spanning 33.6 nm were successfully selected with channel spacing of 0.94 nm and bandwidth of 0.4 nm. With 100 micron-wide pixels separated by 5 microns in the LC-SLM and a 1800 lines/mm grating, we show selection of five channels with channel spacing of 0.78 nm. The bandwidth is 0.43 nm. The channel isolation is better than 20 dB. At a wavelength of 1.5 micron, channel spacing as small as 12.4 GHz can be realized. This device is also expected to be useful for other DWDM applications, e.g., switching and routing.
Microstructure and mechanical properties of surfactant templated nanoporous silica thin films: Effect of methylsilylation
(2003-06-01)
Chen, JY
;
Pan, FM
;
Cho, AT
;
Chao, KJ
;
Tsai, TG
Microstructural and mechanical properties of organic surfactant templated nanoporous thin silica films have been studied by X-ray diffraction, Fourier transform infrared spectroscopy, and nanoindentation. Compared with many other porous low-k dielectrics, the self-assembled molecularly templated nanoporous silica films demonstrate better mechanical properties. This is ascribed to the presence of a well-ordered pore channel structure in the nanoporous silica thin films. Hardness and elastic modulus are strongly dependent on film preparation and modification methods. Trimethylsilylation by hexamethylsilazane vapor treatment effectively enhances the mechanical strength of the nanoporous silica films. When the sol precursor solution is mixed with trimethylchlorosilane (TMCS), the resulting nanoporous films have a weaker mechanical strength. The pore channel structure of the nanoporous silica film becomes less ordered for the TMCS derivatized nanoporous films. In addition, the chemical structure in the silica solid matrix of the TMCS derivatized films is more disordered than those without TMCS modification. The nanoindentation measurement results are discussed in terms of the pore microstructure of the nanoporous silica network and the springback effect due to the presence of trimethylsilyl groups in the nanopores. (C) 2003 The Electrochemical Society.
Minimizing weighted earliness and tardiness penalties in single-machine scheduling with idle time permitted
(2002-12-01)
Chen, JY
;
Lin, SF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, a single-machine scheduling problem with weighted earliness and tardiness penalties is considered. Idle time between two adjacent jobs is permitted and due dates of jobs could be unequal. The dominance rules are utilized to develop a relationship matrix, which allows a branch-and-bound algorithm to eliminate a high percentage of infeasible solutions. After combining this matrix with a branching strategy, a procedure to solve the problem is proposed. (C) 2002 Wiley Periodicals, Inc.
On co-channel interference measurements
(1997)
Chen, JY
;
Su, YT
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
Spectral efficiency of a cellular mobile radio system is enhanced through the reuse of the available spectrum. The resulting co-channel interference, however, also limits Me system capacity. Power control is needed so that co-channel interference can be maintained within a tolerable bound. Therefore, cochannel carrier to interference ratio (CIR) is often used as a quality indicator for received signals. Various power control algorithms assume perfect CIR measurement have been proposed but there is no mentioning of the measurement method. This paper presents viable solutions for real-time CIR estimations under either additive white Gaussian noise (AWGN) or Rayleigh fading condition. A new algorithm that uses the concept of probability density function matching is also proposed to measure CIR in the presence of multiple interferers. Numerical results are provided to demonstrate the usefulness of the proposed algorithms.
Plasma charging damage and water-related hot-carrier reliability in the deposition of plasma-enhanced tetraethylorthosilicate oxide
(1997-07-01)
Lin, YM
;
Jang, SM
;
Yu, CH
;
Lei, TF
;
Chen, JY
This paper presents plasma-enhanced tetraethylorthosilicate oxide process (PETEOS) induced hot-carrier reliability associated with an intermetallic dielectric formed by depositing oxide films from PETEOS, ozone-TEOS, and spin-on glass (SOG), where a single or dual-frequency PETEOS film is deposited as an underlayer followed by an ozone-TEOS deposition for gap filling and a SOG coating for planarization. The impact of PETEOS process conditions such as low-and high-frequency plasma power and PETEOS film thickness on hot-carrier reliability are studied. It is observed that increasing the low- and/or high-frequency plasma power can improve the film quality and moisture-related hot carrier immunity, but at the expense of plasma charging damage. This plasma charging damage accumulates gradually and finally saturates as the deposition of oxide from PETEOS proceeds. In general, a thick PETEOS layer is desired for improving the moisture-related hot carrier immunity. As a result, there is a trade-off between the plasma charging damage and the moisture-related hot carrier immunity. The plasma charging damage is dominant in large devices and the moisture-related hot-carrier immunity is dominant in small devices.
Plasma charging damage and water-related hot-carrier reliability in the deposition of plasma-enhanced tetraethylorthosilicate oxide
(1997-07-01)
Lin, YM
;
Jang, SM
;
Yu, CH
;
Lei, TF
;
Chen, JY
This paper presents plasma-enhanced tetraethylorthosilicate oxide process (PETEOS) induced hot-carrier reliability associated with an intermetallic dielectric formed by depositing oxide films from PETEOS, ozone-TEOS, and spin-on glass (SOG), where a single or dual-frequency PETEOS film is deposited as an underlayer followed by an ozone-TEOS deposition for gap filling and a SOG coating for planarization. The impact of PETEOS process conditions such as low-and high-frequency plasma power and PETEOS film thickness on hot-carrier reliability are studied. It is observed that increasing the low- and/or high-frequency plasma power can improve the film quality and moisture-related hot carrier immunity, but at the expense of plasma charging damage. This plasma charging damage accumulates gradually and finally saturates as the deposition of oxide from PETEOS proceeds. In general, a thick PETEOS layer is desired for improving the moisture-related hot carrier immunity. As a result, there is a trade-off between the plasma charging damage and the moisture-related hot carrier immunity. The plasma charging damage is dominant in large devices and the moisture-related hot-carrier immunity is dominant in small devices.