Browsing by Author "Wu, MC"

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1.2-ps mode-locked semiconductor optical amplifier fiber laser pulses generated by 60-ps backward dark-optical comb injection and soliton compression
(2005-02-07)
Lin, GR
;
Chiu, IH
;
Wu, MC
;
光電工程學系
;
Department of Photonics
Optically harmonic mode-locking of a semiconductor optical amplifier fiber laser (SOAFL) induced by backward injecting a dark-optical comb is demonstrated for the first time. The dark-optical comb with 60-ps pulsewidth is generated from a Mach-Zehnder modulator, which is driven by an electrical comb at a DC offset of 0.3V(pi). Theoretical simulation indicates that the backward injection of dark-optical comb results in a narrow gain window of 60 ps within one modulating period, providing a cross-gain-modulation induced mode-locking in the SOAFL with a shortest pulsewidth of 15 ps at repetition frequency of 1 GHz. The mode-locked SOAFL pulsewidth can be slightly shortened to 10.8 ps with a 200m-long dispersion compensating fiber. After nonlinearly soliton compression in a 5km-long single mode fiber, the pulsewidth, linewidth and time-bandwidth product become 1.2 ps, 2.06 nm and 0.31, respectively. (C) 2005 Optical Society of America.
740-km transmission of 78-channel 64-QAM signals (2.34 Gb/s) without dispersion compensation using a recirculating loop
(2000-09-01)
Wu, MC
;
Wong, JK
;
Tsai, KT
;
Chen, YL
;
Way, WI
A long-distance 1550-nm subcarrier multiplexed lightwave trunk system that transported 78 channels of 64-QAM signals was demonstrated in a recirculating loop experiment. Each channel can achieve a carrier-to-(noise + nonlinear distortion) ratio of 30 dB after 740-km transmission through conventional single-mode fiber without dispersion compensation.
A cost effective approach to establish benchmark for automatic workpiece classification systems
(2002-06-01)
Hsu, SH
;
Hsia, TC
;
Wu, MC
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The utility of an automatic workpiece classification system depends primarily on the extent to which its classification results are consistent with users' judgments. Thus to evaluate the effectiveness of an automatic classification system it is necessary to establish classification benchmarks based on users' judgments. Such benchmarks are typically established by having subjects perform pair comparisons of all workpieces in a set of sample workpieces. The result of such comparisons is called a full-data classification. However, when the number of sample workpieces is very large, such exhaustive comparisons become impractical. This paper proposes a more efficient method, called lean-data classification, in which data on some pair comparison are used to infer the complete pair comparison results. The proposed method has been verified by using a set of 36 sample workpieces. The results revealed that the method could produce a classification that was 78% consistent with the full-data classification while using only 40% of the total data.
A cost model for justifying the acceptance of rush orders
(1996-07-01)
Wu, MC
;
Chen, SY
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
Rush orders are immediate customer demands which exceed the expectation of the currently effective MPS (master production schedule). Even though such orders are quite common to companies in a dynamic market, most existing studies published in the relevant literature seldom discuss the economical justification of accepting such an order. This paper proposes a mixed integer programming model for computing the cost of accepting the production of a rush order. The computed cost value could serve as a valuable reference for justifying the economics of accepting a rush order, and help determine its pricing strategy.
A flexible classification method for evaluating the utility of automated workpiece classification system
(1997)
Hsu, SH
;
Hsia, TC
;
Wu, MC
;
交大名義發表
;
工業工程與管理學系
In group technology, workpieces are categorised into families according to their similarity in design or manufacturing, attributes. This categorisation can eliminate design duplication and facilitate the production of workpieces. Much effort has been focused on the development of automated workpiece classification systems. However it is difficult to evaluate the utility of such systems. The objective of this study was to develop a benchmark classification system based on global shape information for. use in evaluating the utility of workpiece classification systems. A classification system has a high level of utility if its classification scheme is consistent with users perceptual judgement of the similarity between workpiece shapes. Hence, in the proposed method, the consistency between a classification system and users' perceptual judgements is used as an index of the utility of the system. The proposed benchmark classification has two salient characteristics: 1. It is user-oriented, because it is based or? users' judgements concerning the similarity of the global shape of workpieces. 2. It is flexible, allowing users to adjust the criteria of similarity applied in the automated workpiece classification. The development of this classification consisted of three steps. 1. Gathering row data on global shape similarity from a group of representative users and modelling the data by fuzzy numbers. 2. Developing benchmark classification for various similarity criteria by rising fuzzy, clustering analysis. 3. Developing indices for evaluating the appropriate number of workpiece categories and homogeneity within each group. The applicability of the benchmark classification system in evaluating the utility of automated workpiece classification systems was examined.
A genetic algorithm for the optimal design of microwave filters
(1999-12-01)
Hsu, HM
;
Tsai, SP
;
Wu, MC
;
Tzuang, CK
;
電信工程研究所
This paper presents a multiple objective genetic algorithm for determining the component parameters in the design of a microwave filter. In this approach, we first propose a set of fuzzy-based membership functions for modeling the five design specifications (objective functions) of the microwave filter design problem. The five objective functions are then aggregated into a single-valued fitness function. Finally, a set of near-optimal component parameters for the microwave filter can be found by applying the proposed genetic algorithm. A large number of experiments were performed and demonstrated satisfactory results. This approach has three principal merits. First, it counteracts entrapment in a local optimal solution. Second, the processing of multiple objectives is relatively easy. Third, the generated solution is independent of the initial estimate. Significance: This paper presents a multiple objective genetic algorithm for determining the component parameters in the design of a microwave filter.
A multiple criteria decision-making model for justifying the acceptance of rush orders
(1997-12-01)
Wu, MC
;
Chen, SY
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Rush orders are immediate customer demands that exceed the expectation of a currently effective MPS (master production schedule). Decision-makers are often hesitant in the decision of accepting such orders. This paper presents a multiple criteria decision-making model for justifying the acceptance of rush orders for an assembly-to-order production system. Four criteria or production objectives are simultaneously considered and a multiple objective programming technique, the e-constraints approach, is adopted to solve the decision-making problem. This model could give the cost estimation for producing a rush order under various combinations of production objectives. The computed cost value could serve as a Valuable reference for justifying the economics of accepting the rush order, and help to determine its pricing strategy.
A multiple criteria decision-making model for justifying the acceptance of rush orders
(1997-12-01)
Wu, MC
;
Chen, SY
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
Rush orders are immediate customer demands that exceed the expectation of a currently effective MPS (master production schedule). Decision-makers are often hesitant in the decision of accepting such orders. This paper presents a multiple criteria decision-making model for justifying the acceptance of rush orders for an assembly-to-order production system. Four criteria or production objectives are simultaneously considered and a multiple objective programming technique, the e-constraints approach, is adopted to solve the decision-making problem. This model could give the cost estimation for producing a rush order under various combinations of production objectives. The computed cost value could serve as a Valuable reference for justifying the economics of accepting the rush order, and help to determine its pricing strategy.
A neural network approach to the classification of 3D prismatic parts
(1996)
Wu, MC
;
Jen, SR
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
This paper presents a neural network approach to the classification of 3D prismatic parts based on their global shape information modelling. In this approach, a 3D part is modelled by the contours of its three projected views, which are approximately represented by three rectilinear polygons. The global shape information of each polygon is modelled by its simplified skeleton, which originally is of a tree structure and can be represented by several vectors by a conversion method. These vectors are the input to a polygon classifier which is constructed on the basis of the back-propagation neural network model. The classification results of polygons can be used to group the 3D prismatic parts into families in a hierarchical manner, by setting different levels of similarity criteria. The proposed method for classifying 3D workpieces can be used to enhance the productivity of design and manufacturing processes. By retrieving and reviewing similar parts from the part families, the designers or process planners could be greatly assisted in performing a new task. That is, they can avoid the reinvention of an existing design and can create a new design by modifying existing ones.
A project scheduling and staff assignment model considering learning effect
(2006-05-01)
Wu, MC
;
Sun, SH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In a multi-project environment, we sometimes need to periodically schedule the tasks for each project and assign staff to the tasks. Such a decision-making problem has been studied in literature; however, learning effect of staff has not been considered in previous studies. This research formulates a mixed nonlinear program for project scheduling and staff allocation problems, which considers learning effect of staff. The objective function is to minimize outsourcing costs. A genetic algorithm (GA) is proposed to solve the problem. Experiments for solving various sizes of test problems has been carried out to validate the proposed GA.
A pulse-compressed and harmonic mode-locked SOA-EDFA laser link with suppressed phase and supermode noises
(2005)
Lin, GR
;
Chang, YC
;
Wu, MC
;
光電工程學系
;
Department of Photonics
An optically bandpass filtered SOA-EDFL laser link with suppressed phase noise of -110 dBc/Hz and improved supermode noise suppression ratio of 90 dB after harmonic mode-locking and fiber-based pulse compression (to 3.1 ps) are demonstrated.
A similarity inference method for reducing the cost of pair comparison
(2006-01-01)
Wu, MC
;
Wu, SC
;
Hsia, TC
;
Hsu, SH
;
工業工程與管理學系
Group technology must group similar parts into families. In classifying parts based on their global shapes, the similarity of parts has to be manually measured by performing pair comparison. The cost of exhaustively performing pair comparison is quite high when the number of parts to be grouped is large. This paper proposes interval intersection, a novel similarity inference method that effectively infers the pair-comparison data from a set of known data. Justified by empirical experiments, the proposed method outperforms the previous methods when 31% or more of data is known.
A small SiP module using LTCC 3D circuitry for dual band WLAN 802.11 a/b/g front-end solution
(2006)
Wu, MC
;
Chung, SJ
;
電信工程研究所
;
Institute of Communications Engineering
Under the IEEE 802.11a/b/g WLAN specifications, this paper presents a dual-band RF FEM (Front-End Module) on LTCC substrate comprising two diplexers, two band-pass filters and two low-pass filters as a 802.11a/b/g SiP (System-in-Package) solution. To implement, a 5GHz LNA, dual-band DPDT (Double Pole, Double Throw) switch and power detector mounted on the surface of LTCC RF module are also integrated into the proposed module where has only 5.4mm x 4.0mm x 0.9mm in size. On the side of transmitter, the insertion losses of the simulated dual-band FEM are 0.7 and 0.6dB in 2.4-2.5 and 4.9-5.9GHz frequency bands, respectively. The maximum rejection characteristic is -30dB in the second and third harmonic bands. On the side of receiver, the insertion losses are 1.7 and 1.2dB in 2.4-2.5 and 4.9-5.9GHz bands, respectively. The maximum of both the isolation and rejection characteristics is -30dB.
A tool planning approach considering cycle time constraints and demand uncertainty
(2005-09-01)
Wu, MC
;
Hsiung, Y
;
Hsu, HM
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The tool planning problem is to determine how many tools should be allocated to each tool group to meet some objectives. Recent studies aim to solve the problem for the cases of uncertain demand. Yet, most of them do not involve cycle time constraints. Cycle time, a key performance index in particular in semiconductor foundry, should not be ignored. The uncertain demand is modeled as a collection of scenarios. Each scenario, with an occurrence probability, represents the aggregate demand volume under a given product mix ratio. A genetic algorithm embedded with a queuing analysis is developed to solve the problem. Experiments indicate that the proposed solution outperforms that obtained by considering only a particular scenario.
An A-trimmed skeleton for modeling the global shape of polygons
(2006-02-01)
Wu, MC
;
Chen, JR
;
Chuang, JH
;
資訊工程學系
;
工業工程與管理學系
A skeleton is a global shape descriptor that aims to characterize the general appearance of an object to facilitate object classification. Various ways for defining the skeleton of a polygon have been proposed in the literature. Yet, in some cases, these previously proposed skeletons may not intuitively resemble the original polygons and cannot be a good shape descriptor. This research proposes a new definition of skeletons for modeling polygons. The proposed skeleton is termed the area-trimmed (A-trimmed) skeleton. In modeling the global shape of polygons, the A-trimmed skeleton performs much better than other skeletons proposed in the literature. The A-trimmed skeleton can be applied in group technology and facilitate tasks such as punched-part design and fixture design.
An algorithm for converting the contour of a 2D workpiece into a rectilinear polygon
(1996-08-01)
Wu, MC
;
Wang, JT
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
This paper presents an algorithm for converting the contour of a 2D workpiece into a rectilinear polygon. The purpose of providing such a conversion is to model the global shape information of the workpiece. Using an existing algorithm, the rectilinear polygon can further be modeled by a tree structure of line segments, known as the simplified skeleton, which can concisely model the global shape information of a workpiece. That is, workpieces with similar global shape can be classified into the same group by considering the similarity among their simplified skeletons. This algorithm is helpful to enhance the modeling capability of the traditional group technology coding schemes.
An effective application of decision tree to stock trading
(2006-08-01)
Wu, MC
;
Lin, SY
;
Lin, CH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This paper presents a stock trading method by combining the filter rule and the decision tree technique. The filter rule, having been widely used by investors, is used to generate candidate trading points. These points are subsequently clustered and screened by the application of a decision tree algorithm C4.5. Compared to previous literature that applied such a combination technique, this research is distinct in incorporating the future information into the criteria for clustering the trading points. Taiwan and NASDAQ stock markets are used to justify the proposed method. Experiment results show that the proposed trading method outperforms both the filter rule and the previous method. (C) 2005 Elsevier Ltd. All rights reserved.
An efficient method for creating benchmark classifications for automatic workpiece classification systems
(1998)
Hsu, SH
;
Hsia, TC
;
Wu, MC
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The usefulness of an automatic workpiece classification system depends primarily on the extent to tt which its classification results are consistent with users judgements. Thus, to evaluate the effectiveness of an automatic, classification system it is necessary to establish classification benchmarks based on users' judgements. Such benchmarks al are typically established by having subjects perform pair comparisons of all workpieces iir a set of sample workpieces. The result of such comparisons is called a full-data classification. However; when the number of sample workpieces is very large, such exhaustive comparisons become impratical. This paper proposes a more efficient method, called lean classification, in which data on comparisons between the samples and a small number of typical workpieces are used to infer the complete classification results. The proposed,method has been verified by using a small set of 36 sample workpieces and by computer simulation with medium to large sets of 100 to 800 sample workpieces. The results reveal that the method could produce a classification that was 71% consistent with the full-data classification while using only 10% of the total data.
An integrated approach to achieving optimal design of computer games
(2006-07-01)
Hsu, SH
;
Lee, FL
;
Wu, MC
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In a time-to-market environment, designers may not be able to incorporate all the design features in a computer game. For each feature, there are several levels of implementation, which is corresponded to different levels of benefit as well as cost. Therefore, a trade-off decision for determining appropriate levels of implementation is very important, yet has been rarely studied in literature. This paper presents an approach to solve the trade-off decision problem. This approach applies the neural network technique and develops a genetic algorithm to optimize the design of computer games. By this approach, a near-optimal design alternative can be identified in a timely fashion. (c) 2005 Elsevier Ltd. All rights reserved.
An operator staffing and assignment model for foundry fabs
(2005-11-01)
Wu, MC
;
Fu, KC
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This paper presents a linear programming (LP) model for simultaneously solving an operator staffing problem in a semiconductor fab. The problem is to determine the staffing level and assign operators to the staffing positions. The semiconductor fab has the following characteristics: it imposes a no-lay-off policy, but allows overtime; keeps high-quality shop floor operations; aims to control tightly the staffing costs; and faces frequent changes of product mix. The operator staffing problem in such a fab was not addressed in previous literature. The proposed LP model aims to minimize the operator staffing cost. The LP solutions have been examined and were found to be insensitive to stochastic demands modeled by various simulation replicates.