Browsing by Author "Wang, SL"

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A distributed-feedback antenna oscillator
(2000-05-01)
Wang, SL
;
Chou, YH
;
Chung, SJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, a new design of the active transmitting antenna array, called the distributed-feedback antenna oscillator, is proposed. The active array is formed by serially connecting several unit cells to a closed loop. Each unit cell contains an amplifier and a two-port antenna, with an overall insertion gain larger than 0 dB and a phase delay equal to a multiple of 360 degrees. The signal traveling on the loop is amplified and radiated in each unit cell. The radiation fields from all the antennas are then combined in free space. A four-element feedback antenna oscillator operating at 10 GHz is demonstrated by using two-port aperture-coupled microstrip antennas. Simulation results show that multiple oscillation modes with different frequencies and different radiation beams may be excited in the antenna oscillator. By experiment, it is found that each oscillation mode can be built by tuning the biases of the oscillator. The measured radiation pattern for each mode agrees very well with the predicted one. For a single-mode operation with a broadside pattern, bandstop filters of a simple geometry are designed and embedded in the oscillator to suppress the unwanted oscillation modes. Finally, the influence of the bias condition on the radiation power of the single-mode oscillator is investigated.
A hierarchical case knowledge acquisition method for troubleshooting
(2003)
Wang, SL
;
Hsu, SH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The authors propose a Hierarchical Case-based Knowledge Acquisition Method (HCBKA) based on Case-based Reasoning (CBR). The proposed KA method is made LIP of two components: a knowledge elicitation part in which Cognitive Task Analysis (CTA) techniques are applied to extract application-specific knowledge, and a knowledge organization part in which a case-based algorithm, hierarchical clustering, and ontology techniques are integrated to classify and encode case knowledge.
A multi-path QoS routing protocol in a wireless mobile ad hoc network
(2002)
Liao, WH
;
Wang, SL
;
Sheu, JP
;
Tseng, YC
;
資訊工程學系
A mobile ad hoc network (MANET) is one composed of a set of mobile hosts capable of communicating with each other without the assistance of base stations. This paper considers the QoS (quality-of-service) routing problem in a MANET, which is important for many real-time multimedia applications. We propose an on-demand protocol for searching for a multi-path QoS route from a source host to a destination host in a MANET, where a multi-path is a network with a source and a sink satisfying certain bandwidth requirement. Existing works all try to find a uni-path to the destination. The basic idea is to distribute a number of tickets from the source, which can be further partitioned into subtickets to search for a satisfactory multi-path. Through simulations, we justify that the value of our multi-path protocol is in its flexibility: (i) when the network bandwidth is very limited, it can offer a higher success rate to find a satisfactory QoS route than those protocols which try to find a uni-path, and (ii) when the network bandwidth is sufficient, it can perform almost the same as those protocols which try to find a uni-path (in both routing overhead and success rate).
A multi-path QoS routing protocol in a wireless mobile ad hoc network
(2001)
Liao, WH
;
Tseng, YC
;
Wang, SL
;
Sheu, JP
;
資訊工程學系
A mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations, This paper considers the QoS (quality-of-service) routing problem in a MANET. We propose an on-demand protocol for searching for a multi-path QoS route from a source host to a destination host in a MANET, where a multi-path is a network with a source and a sink satisfying certain bandwidth requirement. Existing works all try to find a uni-path to the destination. The basic idea is to distribute a number of tickets from the source, which can be further partitioned into sub-tickets to search for a satisfactory multi-path. Through simulations, we justify that the value of our multi-path protocol is on its flexibility: (i) when the network bandwidth is very limited, it can offer a higher success rate to find a satisfactory QoS route than those protocols which try to find a uni-path, and (ii) when the network bandwidth is sufficient, it can perform almost the same as those protocols which try to find a uni-path (in both routing overhead and success rate).
A Web-based CBR knowledge management system for PC troubleshooting
(2004-04-01)
Wang, SL
;
Hsu, SH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Using case-based reasoning (CBR), the authors integrate the techniques of cognitive task analysis (CTA), hierarchical clustering and ontology and propose a Web-based CBR knowledge management (KM) system for investigating the construction of a KM system with multiple information techniques to support KM activity in industry. The maintenance service centres of a computer company are used as an example to illustrate extracting the maintenance knowledge necessary to construct a PC troubleshooting KM system. The effectiveness of applying a Web-based CBR KM system to support KM activities in the KM life cycle is subjected to practical verification.
Synthesis of carbon-chain tethered bistetraoxa-cage compounds
(1998-02-01)
Chern, JH
;
Wu, HJ
;
Wang, SL
;
Liao, FL
;
應用化學系
Carbon-chain tethered bistetraoxa-cage compounds 7a-c and 8a-c were synthesized from 2-methyl-furan in a four-step sequence. They were obtained from ozonolysis of the syn bisadducts 5a-c and the anti bisadducts 6a-c in dichloromethane at -78 degrees C followed by reduction with dimethyl sulfide. The structure of the anti bisadduct 6a was proven by X-ray crystallographical analysis.