• The Journal of Society for e-Business Studies
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• v.15 no.2
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• pp.191-203
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• 2010

Recently applications of RFID technologies in production and logistics systems are expanding. In this research, we deal with workflow modeling methods for handling RFID-tagged parts. We verified that the material flow processes in a RFID system can be designed and assessed using workflow modeling notations, and suggested available process patterns using BPMN. In addition, we proposed an algorithm to monitor the exact status of flows and determine whether some of the events are ghost reads or not by referring predefined workflow definitions. The major contribution of this research is that it has demonstrated how well-established workflow modeling methods can be applied to RFID-based systems.

• The Journal of Society for e-Business Studies
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• v.19 no.3
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• pp.143-158
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• 2014

Making decisions on prices must be an important task for sellers to stay competitive in on-line markets. Because the emergence of price-comparison web sites led buyers to be more sensitive to the prices, adjusting prices became very important to on-line sellers. This study collected and analyzed the data of prices on computing peripheral devices posted at a popular web site that enabled buyers to compare the prices on the same products. By analyzing the timings of price adjustments among different sellers using Monte Carlo simulation, we explored the possibility of price coordinations among those sellers. The results indicated that online sellers adjusted their prices on a daily basis rather than a weekly basis and the tacit coordination on the price changes was identified.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.58-59
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• 2013

본 과제에서는 3.3kV/220V, 6kVA 용량의 양방향 지능형 반도체 변압기의 새로운 회로 구성을 제안하고 그 동작과 성능을 분석하였다. 제안하는 3상 반도체변압기는 1.9kV/127V 단상 반도체 변압기 모듈 3대를 Y-결선으로 구성하였으며, 각 단상 반도체 변압기는 고압 고주파 AC-DC 정류기와 저압 양방향 DC-DC-AC 컨버터로 구성되어 있다. 제안하는 3.3kV/220V, 6kVA 3상 반도체변압기를 제작하고 실험을 통해 그 동작과 성능을 검증하였다. 먼저 1차적으로는 3상 반도체변압기의 정상동작에 대해 실험을 실시하고 그 후에는 3상 입력전압에 외란이 발생하였을 때 보상성능을 순방향 조류와 역방향 조류 2가지 경우로 나누어 실험을 실시하고 그 결과를 분석하였다. 분석한 결과 제안하는 반도체변압기는 양방향 전력흐름이 가능하고 입력전압에 Sag가 발생한 경우에도 이를 보상하여 수전단이나 부하에 전력공급이 가능함을 알 수 있었다.

• The Journal of Society for e-Business Studies
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• v.11 no.3
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• pp.89-108
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• 2006

This study is to survey on the status of human resource training programs related to ubiquitous technologies and services of domestic universities. So, this study develop a classification system about human resource related to ubiquitous technologies and services. We propose the implications and plans which are based on the status of human resource training programs related to ubiquitous technologies and services. Human resources related to ubiquitous technology are classified by the flow of information in ubiquitous environment. And human resources related to ubiquitous service are classified by ubiquitous user view. This study can be used to find collaboration alternatives for breeding up ubiquitous human resources and referred to analyzing on the supply and demand of ubiquotous human resources.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.491-499
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• 2007

The variation of a load characteristic in the motor drive is one of the most important consideration. Because the current flowing into the motor generally varies according to the load variation, it needs to design the motor drive circuit properly in accordance with the load variation. However, the load variation of the drum washing machine is irregular and large due to the water flow and reverse load torque. Therefore, to design the motor drive circuit considering this load pattern, simulation results shows the load pattern modeling of the drum washing machine based on the physical analysis in this paper.

• The Journal of Society for e-Business Studies
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• v.14 no.1
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• pp.35-56
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• 2009

Many process modeling techniques, such as Petri-net, UML Activity Diagram, and EPC, are used to design process models. In this paper, we analyze ubiquitous process design based on workflow patterns. In particular, we focus on process design using active rules that have the form of Event-Condition-Action, and deal with the WS-ECA language, which was devised for ubiquitous web services coordination. We first check whether workflow patterns can be designed with ECA rules, and we then provide WS-ECA representations for ECA rules of the patterns. The contribution of this paper is that ECA rule-based process models were presented based on workflow patterns and they can be a guideline for ubiquitous process modeling.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.5
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• pp.42-51
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• 2001

Vehicle detection is the basic of traffic monitoring. Video based systems have several apparent advantages compared with other kinds of systems. However, In video based systems, shadows make troubles for vehicle detection, especially active shadows resulted from moving vehicles. In this paper, a new method that combines background subtraction and edge detection is proposed for vehicle detection and shadow rejection. The method is effective and the correct rate of vehicle detection is higher than 98% in experiments, during which the passive shadows resulted from roadside buildings grew considerably. Based on the proposed vehicle detection method, vehicle tracking, counting, classification and speed estimation are achieved so that traffic parameters concerning traffic flow is obtained to describe the load of each lane.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.246-253
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• 2013

This paper addresses the technology of active flow control for stabilizing a flow field. In order for flow field modeling from the control point of view, the huge-data set from CFD(computational fluid dynamics) are reduced by using a POD(Proper Orthogonal Decomposition) method. And then the flow field is expressed with dynamic equation by low-order modelling approach based on the time and frequency domain analysis. A neural network flow estimator from the pressure information measured on the surface is designed for the estimation of the flow state in the space. The closed-loop system is constructed with feedback flow controller for stabilizing the vortices on the flow field.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.3
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• pp.221-228
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• 2008

In the 2-phase excited BLDC motor drives using a unipolar PWM scheme, there exists, in some cases, a unwanted leakage current which flows through the anti -parallel diode in the non-excited phase leg of the inverter. In this paper the cases in which the leakage current exists and the influence of the leakage current are analyzed, and a novel unipolar PWM scheme which can eliminate the leakage current is proposed. The leakage current increases as the motor speed is increased or PWM duty is decreased, and as a result the output power of the motor is reduced considerably. The effectiveness of the proposed unipolar PWM scheme isverified through the comparative simulations and experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.357-357
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• 2008

Spin injection experiment is conducted in epitaxially grown Fe/GaAs hybrid structure. For the formation of Schottky tunnel barrier between Fe and GaAs layers, highly n-doped GaAs layers are grown after n-doped channel layer. A non-local measurement, a voltage measurement probes do not contain a charge current path, is used for detecting only the chemical potential differences by the spin transport. As a result, the dips that are nicely matched with antiparallel region are obtained.