Browsing by Author "Chen, HT"

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A broad-beamed transponder using spatial power combining (SPC) technique
(1997)
Chen, HT
;
Chung, SJ
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
This paper presents a new microwave/millimeter-wave transponder using active microstrip antenna array. The array elements are arranged by using the Van Atta retrodirectivity design so that the fields radiated from all the transmitting antennas combine spatially in the wave-incidence direction, which cancel with each other in other directions. The measured returning-field pattern of the transponder is illustrated, which shows good agreement with the calculation pattern.
Design of a planar array transponder with broad responding beam
(1997-09-01)
Chen, HT
;
Chung, SJ
;
電信工程研究所
;
Institute of Communications Engineering
A new planar array transponder, including four active receiving-transmitting microstrip antenna pairs, were demonstrated by using the Van Atta array design. The fields retransmitted by all the antenna pairs spatially combine in the wave-incidence direction while interfere with each other in other directions, so that the transponder responds the signal only to the on-line interrogator. The measured 10 dB (5 dB) responding beamwidth for the array transponder is 106 degrees(80 degrees), which is approximately the same as that of a transponder with a single antenna pair. Also, the measured radar cross section (RCS) patterns for the transponder at the on state (with bias) and off state (without bias) were compared. More than 20-dB difference between the patterns of these two states has been observed.
Design of a planar array transponder with broad responding beam
(1997-09-01)
Chen, HT
;
Chung, SJ
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
A new planar array transponder, including four active receiving-transmitting microstrip antenna pairs, were demonstrated by using the Van Atta array design. The fields retransmitted by all the antenna pairs spatially combine in the wave-incidence direction while interfere with each other in other directions, so that the transponder responds the signal only to the on-line interrogator. The measured 10 dB (5 dB) responding beamwidth for the array transponder is 106 degrees(80 degrees), which is approximately the same as that of a transponder with a single antenna pair. Also, the measured radar cross section (RCS) patterns for the transponder at the on state (with bias) and off state (without bias) were compared. More than 20-dB difference between the patterns of these two states has been observed.
Motion activity based semantic video similarity retrieval
(2002)
Chen, DY
;
Lee, SY
;
Chen, HT
;
資訊工程學系
;
Department of Computer Science
Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. In this paper, a novel mechanism of similarity retrieval is proposed. Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, Discrete Cosine Transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory information and preserves the Euclidean distance between feature vectors. Experiments are performed oil MPEG-7 testing videos, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.
Multi-robot cooperative edge detection using Kalman filtering
(2004)
Song, KT
;
Chen, HT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper Presents a design and implementation of cooperative edge detection of multiple mobile robots in an indoor environment. We propose a method to fuse sensory data from two mobile robots at different locations based on Kalman filtering techniques. To demonstrate the proposed method, we constructed two mobile robots for experimental purpose. A USB Web camera was put at the front of each robot for environment recognition. linage acquisition and processing are performed onboard the robot exploiting a Linux-based embedded platform. Processed scenic range data from robots are transferred through wireless Ethernet to a robot-home server, where a global representation of the environment is maintained. The constructed map can be accessed at a remote site for tele-operation of the robots through Internet. Each robot can update its knowledge of the world by downloading the map from the server. Experimental results of two-robot cooperative sensing in a test environment are presented to demonstrate the effectiveness of the proposed method.
Object based video similarity retrieval and its application to detecting anchorperson shots in news video
(2003)
Chen, HT
;
Chen, DY
;
Lee, SY
;
資訊工程學系
;
Department of Computer Science
Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. In this paper, a novel mechanism of similarity retrieval is proposed Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity, are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, Discrete Cosine Transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory, information and preserves the Euclidean distance between feature vectors. Experiments are performed on MPEG-7 testing video streams, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.
Performance assessment of processing and delivery times for very large scale integration using process capability indices
(2002)
Chen, KS
;
Chen, HT
;
Tong, LI
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process quality and delivery time have received increasing attention in the highly competitive electronics industry. Many studies have proposed process capability indices (PCIs) to assess process effectiveness. However, methods to assess the performance in terms of processing and delivery times of products have seldom been discussed. The conventional PCIs can no longer assess the processing time (PT) and delivery time (DT) performance objectively or identify the relationship between PCIs and the non-conformance rate of PT or the conformance rate of DT. Lacking an effective performance index or an objective testing procedure to assess process/product performance will lead to inefficiency or a high manufacturing management overhead cost. Therefore, this study offers effective performance indices (i.e., PCIs) to assess the PT and DT performance for very large scale integration (VLSI). The uniformly minimum variance unbiased (UMVU) estimators of the proposed PCIs are derived under the assumption of a normal process distribution. The PCI estimators are then employed to construct a one-to-one relationship between the PCIs and the conformance rate of DT or non-conformance rate of PT, respectively. Finally, hypothesis testing procedures for the proposed PCIs are also developed. The testing procedure can be used to determine whether DT or PT can satisfy a customer's requirements.