• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.1
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• pp.63-70
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• 2009

The purpose of this paper is to propose a CSMA/CA protocol to reduce the delay time and increase the throughput of the original CSMA/CA protocol. In underwater environments, the efficiency of the protocol is reduced due to the increase of the propagation delay time, which results in increase of the collision possibility causing lowering of the transmission efficiency Considering this propagation delay, this paper propose to insert the STANDBY frame in a CTS packet in order to avoid the TimeOut status of the CSMA/CA protocol. According to the simulated test results, proposed protocol is increased about 20% throughput than original CSMA/CA protocol. And the more value of propagation per transmission delay 'a' is low, the more throughput of protocol is better.

• Journal of KIISE:Software and Applications
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• v.27 no.11
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• pp.1106-1114
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• 2000

컴퓨터 분야에서 에이전트의 개념은 전자 상거래, 정보 검색과 같은 많은 어플리케이션들에 응용되어 중요 시 되고 있다. 하지만, 아직까지 지능성을 가진 테스트 도구는 없었다. 이 논문에서 제안하는 테스트 에이전트 시스템은 에이전트의 특성을 가지고 테스터를 도와주는 테스트 도구이다. 테스트 에이전트 시스템은 객체지향 테스트 프로세스를 따라 테스터의 일을 대행해 주고, 테스터의 간섭을 최소화 시켜 준다. 이 시스템은 자동 생성된 많은 양의 테스트케이스에서 중복이 없고 일관성 있는 테스트케이스를 지능적으로 선택하여 테스트 시간을 단축시켜 준다. 테스트 에이전트 시스템은 3개의 에이전트 User Interface Agent, Test Case Selection & Testing Agent, Regression Test Agent로 구성된다. 특히 Test Case Selection & Testing Agent은 RE-Rule과 CTS-Rule을 통하여 중복이 없고 일관성 있는 테스트케이스를 지능적으로 선택하며, Regression Test Agent는 RRTIS-Rule을 통해 리그래션 테스트 항목을 지능적으로 선택한다.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.81-84
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• 1998

In this paper, we implemented this failure detecting and monitoring system for high-pressure natrium lamps and ballasts. The hall CTs of the local detecting system measure the current flowing into natrium lamps via ballasts and acertain whether the natrium lamps or ballasts are out of order or not. These test data are transmitted to the main monitoring system. So, we can see the status of the natrium lamps or ballasts promptly.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.771-776
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• 2007

Purpose: Complete release of the transverse carpal ligament (TCL) is accepted as the standard treatment for carpal tunnel syndrome (CTS). However, loss of grip and pinch power are reported in some patients after complete release of the TCL. This study was designed to evaluate the effectiveness of complete versus partial carpal tunnel release by using the inching technique. Methods: Nineteen patients (a total of 27 hands) who each had a confirmed diagnosis of CTS were selected from September 2002 to February 2003. The cases were divided into three groups(mild, moderate and severe) based on preoperative electrodiagnostic studies. The patients with partial carpal tunnel syndrome were classified into the mild or moderate groups, while patients with complete carpal tunnel syndrome were classified into the moderate or severe groups. Patient oriented data (functional and symptomatic) were collected and electrophysiologic studies were undertaken preoperatively and postoperatively(on the 2nd week, 1st month, 3rd month and 6th month after surgery).Results: In this study, the mild and moderate groups showed both good functional and symptomatic results and improvements in electrophysiologic studies.Conclusion: Carpal tunnel syndrome patients classified into mild or moderate groups based on nerve conduction studies, and whose precise compression sites were pinpointed using the inching technique, can be treated by partial carpal tunnel release.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.185-192
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• 1999

The purpose of this study is to investigate the physical disorders of CTDs prevalent among dentists who are exposed to job risk factors. The average total work time per week of subjects(N=117) was 44$\pm$6 hours, work time with one patient was 20$\pm$10 minutes, and their daily tasks were consisted of extraction, filling, preparation, nerve amputation of tooth. The results of this study are as follows: 1) The discomfort test shows that dentists suffer from discomfort/pain in upper extremities. 2) The work environment test related to CTDs shows that female dentists feel more uncomfortable in the height of chairs than male dentists. 3) The symptom test shows that female dentists suffer from more pain in fingers or wrists at night than male dentists.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2127-2137
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• 2016

In this paper, characteristic tests for current transformers with maximum mA secondary current of 250 mA is performed. The purpose of this paper is not only to test the mA current transformers by following the IEEE Draft Standard for Current Transformers with Maximum mA Secondary Current of 250mA, but also to take into consideration certain applications in the use of the mA CTs for billing purposes.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.153-159
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• 2008

We have developed an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) without any precise standard CT by measuring four parameters in a CT equivalent circuit. The excitation admittance in the CT equivalent circuit can be obtained by employing standard resistors with negligible reactive component. The secondary leakage impedance in the CT equivalent circuit can be measured using a universal impedance bridge. The method was applied to CTs under test with the wide current ratios in the range of 5 A / 5 A - 5,000 A / 5 A and 5 A / 1 A - 5,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Canada using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.

• Journal of Korean Neurosurgical Society
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• v.52 no.6
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• pp.528-533
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• 2012

Objective : In the pediatric population the skull has not yet undergone ossification and it is assumed that the diagnostic rate of skull fractures by simple X-rays are lower than that of adults. It has been recently proposed that the diagnostic rates of skull fractures by 3-dimensional computer tomography (3D-CT) are higher than simple X-rays. The authors therefore attempted to compare the diagnostic rates of pediatric skull fractures by simple X-rays and 3D-CTs with respect to the type of fracture. Methods : One-hundred patients aged less than 12 years who visited the Emergency Center for cranial injury were subject to simple X-rays and 3D-CTs. The type and location of the fractures were compared and Kappa statistical analysis and the t-test were conducted. Results : Among the 100 pediatric patients, 65 were male and 35 were female. The mean age was $50{\pm}45$ months. 63 patients had simple skull fractures and 22 had complex fractures, and the types of fractures were linear fractures in 74, diastatic fractures 15, depressed fractures in 10, penetrating fracture in 1, and greenstick fractures in 3 patients. Statistical difference was observed for the predictive value of simple skull fractures' diagnostic rate depending on the method for diagnosis. A significant difference of the Kappa value was noted in the diagnosis of depressed skull fractures and diastatic skull fractures. Conclusion : In the majority of pediatric skull fractures, 3D-CT showed superior diagnosis rates compared to simple skull X-rays and therefore 3D-CT is recommended whenever skull fractures are suspected. This is especially true for depressed skull fractures and diastatic skull fractures.

• Journal of KIISE:Software and Applications
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• v.28 no.10
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• pp.732-742
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• 2001

The concept of an agent has become important in computer science and has been applied to the number of application domains such electronic commerce and information retrieval. But, no one has proposed yet in software test. The test agent system applied the concept of an agent to software test is new test tool. It consists of the User Interface Agent. the Test Case Selection & Testing Agent and the Regression Test Agent. Each of these agents, with their intelligent rules, carry out the tests autonomously by empolying the object-oriented test processes. This system has 2 advantages. Firstly since the tests are carried our autonomously, it minimizes tester interference and secondly, since redundant-free and consistent effective test cases are intellectually selected, the testing time is reduced while the fault detection effectiveness improves. In this paper, by actually showing the testing process being carried out autonomously by the 3 agents that form the TAS, we show that the TAS minimizes tester interference. By also carrying out the 4 different types of experiments on the RE-Rule, CTS-Rule, overall TAS experiment, and the fault-detection effectiveness experiment on the RE-Rule, we show the cut-down on the testing time and improvement in the fault detection effectivity.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.253-256
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• 2001

This paper describes a high speed MAC(Media Access Control) function chip for IEEE 802.11 MAC layer protocol. The MAC chip has control registers and interrupt scheme for interface with CPU and deals with transmission/reception of data as a unit of frame. The developed MAC chip is composed of protocol control block, transmission block, and reception block which supports the BCF function in IEEE 802.11 specification. The test suite which is adopted in order to verify operation of the MAC chip includes various functions, such as RTS-CTS frame exchange procedure, correct IFS(Inter Frame Space)timing, access procedure, random backoff procedure, retransmission procedure, fragmented frame transmission/reception procedure, duplicate reception frame detection, NAV(Network Allocation Vector), reception error processing, broadcast frame transmission/reception procedure, beacon frame transmission/reception procedure, and transmission/reception FIEO operation. By using this technique, it is possible to reduce the load of CPU and firmware size in high speed wireless LAN system.