• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.485-491
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• 2008

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.73-74
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• 2011

Phase-shedding, one famous technology for multi-phase converters, is implemented in a bi-directional multi-phase converter for ESS. It reduces active operating modules at light load to compensate efficiency. Shedding point, the load level where the converter changes the number of active modules, is important factor that affects the effect of phase-shedding. Loss analysis is done for determining shedding point. Phase-shedding hysteresis is applied so that excessive phase transition is avoided. This paper proposes shedding point correction where the shedding point is adaptively corrected by calculating a new shedding point.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.27-30
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• 1991

Recently, the phenomena of voltage instability have become major concern in power system, these phenomena are closely related to what are called multiple load flow solutions and calculation methods on these solutions have developed. The multiple solutions concerned with phenomena are pair solutions in heavy loaded contion. But conventional methods require much run time to find this pair solutions and unusual generation patten in the condition of multiple solutions. In this paper, by using concept of existence condition of multiple solutions, calculation method on the multiple load flow solutions is presented which find the pair solutions in light loaded condintion.

• Journal of Power Electronics
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• v.9 no.3
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• pp.403-409
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• 2009

Automatically tuned passive filters can improve power quality to a great extent in power systems. A novel three-phase shunt auto-tuned filter is designed to effectively compensate source current harmonics and to provide reactive power required by the non-linear load, which draws a highly reactive, harmonic-rich current from the supply. An artificial neural network (ANN) based controller selects filter component values in accordance with reactive power requirement and harmonic compensation. Traditional passive filters are permanently connected to the system and draw large amounts of source current even under light load conditions. By using auto-tuned filters, the passive filter components can be controlled according to load variations and, hence, draw only required source currents. The selection is done by the ANN with the help of a properly tuned knowledge base to provide instantaneous compensation using a digital controller.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.1-7
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• 1992

This paper proposes reservation-based multiple access with variable frame length (RMAV) which is a new multiple access scheme for indoor and outdoor wireless data communications. RMAV is based on the slot reservation scheme and adopts a frame structure with variable frame length. The frame length increases as the number of active terminals and/or the system load increases. As a result, RMAV is adapted to the changes in the traffic pattern, and it offers short delay in light load conditions and high throughput in heavy load conditions. The performance of RMAV is evaluated by simulations. In addition, it is compared with the performance of PRMA(packet reservation multiple access).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1306-1314
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• 2015

This paper deals with a switching method of a three-phase interleaved bidirectional DC-DC converter to obtain high efficiency in wide load range. The proposed soft-switching method provides ZVS and ZCS at turn-on, and ZVS at turn-off of the switch as well as considerably reduced conduction loss in light load. Simulation and experiment are carried out with a bidirectional DC-DC converter having the power rating of 3 [kW], and those results show the validity of the proposed switching method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.2
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• pp.178-183
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• 1984

The stresses in lubricants by external force lead to rise in temperature and drop in viscosty, and the performance of lubricants decrease by this phenomena. The processes of shear stress generation and relaxation are linear under light load condition but those are changed into nonlinearly over a certain limit of load and speed, and this phenomena influences to viscosty change. This study investigates dense fluid which carries property change for high shear rate by using molecular dynamics, and that result can be related to research a behavior of property change of lubricants under high speed and heavy load.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1118-1123
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• 2003

Based on the design requirements(size, strength, structure, weight, and etc.) for the rubber-tired AGT vehicle, carbody made of aluminum alloy is designed. The analysis of strength and stiffness is performed in the designed carbody, which results in the modification for optimal shapes and structures. It consists of a under frame, side frame, roof frame, end frame and forehead frame. After the carbody manufactured, tests are performed, which are vertical load test, longitudinal compressive load test, twisting load test, twisting natural frequency measurement, bending natural frequency measurement and 3 points supporting test. Results of them can guarantee a structural safety.

• Journal of the Korea Society for Simulation
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• v.9 no.1
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• pp.11-19
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• 2000

The main idea behind the Intelligent Networks (IN) concept is the separation of switching function from the service control, in order to meet various service requirements of subscribers and development of new services in time. The (N+l) architecture of the IN service system consists of front-end processors (FEP) and back-end processors (BEP), which is in service in a domestic telecommunication company, and balances the traffic load for services among the processors. Under this architecture, the IN service system can distribute the traffic load dynamically, and M services are easily launched and manipulated minimizing impacts on the existing services. This paper traces the performance of the (N＋1) structured system by means of the simulation approach, and shed a light on the result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.364-368
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• 1992

The conventional loading process of workpieces for a CNC lathe is performaed either by human or by a general robot. It is not suitable for a general robot to load workpieces because of high price and inefficiency. Starting from the description of the environment around CNC lathes and the analysis ofloading process, we have developed the task-oriented loading manipulator. The characteristics of a loading manipulator are the following: to load/unload heavy workpieces, to decrease the whole porcess time. The air-chuck to load heavy workpiece has high clamping force and light weight. A loading manipulator has accomplished both the integration of independent automation techniques and cost-down effect of product. A loading manupulator developed in this project has been designed for general loading process. The loading manipulator is capable of carrying heavy payload with respect to weight of robot in short cycle time.