University of the Thai Chamber of Commerce

About: University of the Thai Chamber of Commerce is a education organization based out in Bangkok, Thailand. It is known for research contribution in the topics: Corporate social responsibility & General equilibrium theory. The organization has 223 authors who have published 422 publications receiving 5380 citations.

A Four-Quadrant Operation Diagram for Thermoelectric Modules in Heating–Cooling Mode and Generating Mode

Abstract: The operation of a thermoelectric module in heating–cooling mode, generating mode, and regenerating mode can be discussed in terms of power, cooling load, and current. A direct current machine in motoring mode and generating mode and an induction motor in motoring mode and regenerating mode are analogous to thermoelectric modules. Therefore, the first objective of this work is to present the four-quadrant (4-Q) operation diagram and the 4-Q equivalent circuits of thermoelectric modules in heating–cooling mode and generating mode. The second objective is to present the cooling and regenerating curves of a thermoelectric module in cooling mode and regenerating mode. The curves are composed from the cooling powers and the generating powers, the input and output current, the thermal resistance of the heat exchanger, and the different temperatures that exist between the hot and cold sides of the thermoelectric module. The methodology used to present the data involved drawing analogies between the mechanical system, the electrical system, and the thermal system; an experimental setup was also used. The experimental setup was built to test a thermoelectric module (TE2) in cooling mode and regenerating mode under conditions in which it was necessary to control the different temperatures on the hot and cold sides of TE2. Two thermoelectric modules were used to control the temperature. The cold side was controlled by a thermoelectric module labeled TE1, whereas the hot side was controlled by a second thermoelectric module labeled TE3. The results include the power, the cooling load, and the current of the thermoelectric module, which are analogous to the torque, the power, the speed, and the slip speed of a direct current machine and an induction motor. This 4-Q operation diagram, the 4-Q equivalent circuits, and the cooling and regenerating curves of the thermoelectric module can be used to analyze the bidirectional current and to select appropriate operating conditions in the cooling and regenerating modes.

Social Networking Ontology Engineering Walkthrough: Practical Approach for Non-Expert User Learning

Abstract: The utilization of ontologies in knowledge management has become very well accepted in many approaches for instance database, semantics, agent, natural language processing, etc. Artificial intelligent researchers have originally applied the word "ontology" from Philosophy fields which means "being existence", then the word spread in many scientific domain and ontologies are now used in several developments. The purpose of this research is to present the simple methodologies and methods used to build/adapt/integrate ontologies from the system requirement or by reusing and re-engineering other ontologies; also a process of merging approach will be addressed. The normal ontology engineering will not be suitable for non-expert user; and there are some tools for helping the user to accomplish the ontology engineering task, however, it is not that simple. This paper mentioned the observation and figure out the practical methodology for non-expert user to learn and create simple ontology with little background of them. This paper mentioned the ontology and ontology engineering revisits. Also the main section in this paper mentioned the scenario walkthrough about reality of how non-expert user creates the simple ontology by using suggested and existing methodologies. The last section is recommendation and suggestion from the research experimental which explain the proper ontology developing methodology for non-expert user.

Performance comparison of DTC of open-circuit fault PM BLAC motor based on modified voltage and current model flux estimators

Abstract: Performance of direct torque control (DTC) of three-phase permanent magnet brushless AC (PM BLAC) motor having one phase open-circuit fault (OPOF) is investigated. Modified voltage model flux estimator and current model flux estimator are employed in estimation of stator flux linkages of the motor. The developed torque is then calculated based on the estimated flux linkages. Three-leg inverter is employed in the post-fault operation and a switching table is designed subjected to the topology. Performances of the systems using different flux estimation are compared. Developed torque and stator flux linkages of the faulty motor are regulated and at a constant torque operation stator currents are automatically developed to stabilized the system. Performances of the systems are verified by experimental results.