• 대한전자공학회논문지TC
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• 제45권2호
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• pp.92-96
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• 2008

실용적은 통신 시스템은 고정된 한 부호화율이 아닌 다양한 부호화율에서 동작을 할 필요가 있다. 본 논문에서는 서로 다른 다양한 부호화율을 위한 LDPC(Low-Density Parity-Check) 부호를 분석했다. 한 특정한 모부호에서 행을 분할하여 LDPC 부호가 서로 다른 부호화율에서도 동작하도록 하는데 이 기술의 장점은 부호화율이 변하더라도 LDPC 부호의 블록 길이가 항상 일정하게 유지됨으로써 천공(Puncturing) 이나 쇼트닝(Shortening) 기법처럼 블록 길이가 줄어드는 단점을 보완한다는 것이다. 행 분할(Row-splitting) 기법이라 명명한 이 기술은 말 그대로 H 행렬의 행을 분할하여 부호화율을 낮추기 때문에 비슷한 행 합산(Row-combining) 기법의 단점 또한 보완할 수 있다.

• 한국건설관리학회논문집
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• 제18권5호
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• pp.59-67
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• 2017

공사 완료 시점에는 다양한 마감 공정들이 집중적으로 수행된다. 이는 현장관리자의 업무 부담을 가중시켜 경험에 근거한 임기응변적 품질관리 업무수행을 강제함으로써 감독자나 작업자의 개인역량에 따라 공사품질의 편차가 발생한다. 또한 품질관리와 관련된 정보가 시방서, 도면 등 다양한 유형의 문서에 산재하여 점검사항이 누락되는 경우가 빈번하다. 하자예방과 관련된 정보들을 체계적으로 저장하고, 상호참조 가능한 상태로 연계하여 실무자에게 점검업무 전 또는 수행 중에 효과적으로 제공할 수 있는 도구가 필요하다. 본 논문은 공동주택 마감공사의 품질점검 대상 액티비티 또는 실 단위로 필요한 정보를 체계적으로 저장 검색이 가능한 품질점검 지원 모델을 제안한다. 시방서, 설계기준, 체크리스트, 법규, 하자사례, 도면을 마감공사 프로세스 및 실과 연계하여 하자예방 정보베이스와 정보연계 넥서스를 구축하였으며 이를 바탕으로 정보등록 및 검색 인터페이스를 제시하였다. 내용적으로 다양한 하자예방 정보들을 마감공사 액티비티 및 실을 중심으로 연계하여 활용 가능한 틀을 제시함으로써 일정 수준 이상의 시공품질 확보에 기여할 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3512-3517
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• 2007

Nuclear power plant has many external fire hydrants that have to operate in the state of emergency such as facility fire, forest fire. The valve stem of one among them was broken 3 times for 4 years. It had long valve stem and operated under high water pressure. The elongation and the tensile strength for the broken valve stem was measured to examine the defect of material property. And the vibration level and the natural frequencies was detected to check the resonance. As the result of a diagnosis, the cause of this fault is proven buckling of long valve stem.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.571-578
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• 2005

Stresses of main stop valve and control valve casings for the steam turbines of power plants are analyzed by the finite element method. The stress intensity is obtained to check the results on the basis of the design criteria of ASME boiler and pressure vessel code. To verify accuracy of the finite element analysis. analyzed stresses are compared with those measured during the hydrostatic pressure test. Stress category drawings. which play an important role in evaluating casting defects, are produced from the analysis results, and important points in casting of the valve casings are discussed in terms of the stress category.

• Journal of Chest Surgery
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• 제11권1호
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• pp.75-80
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• 1978

Coarctation of the aorta, a well known congenital cardiovascular defect, can be recognized in most instances by simple findings of physical examination. This condition shortens life if untreated, but it can be corrected surgically to render the patient functionally normal. It seems relatively rare in Asian. We experienced two cases of coarctation of the aorta which were treated surgically. The first case was 17 years old male with juxtaductal type of coarctation of the aorta. The second was 7 years old female with preductal type of coarctation of the aorta and combined anomaly of PDA and she had been in congestive heart failure. In both cases, coarctated segments of the aorta were resected and end to end anastomosis were performed. In the second case, PDA was closed by division before resection of the coarctated segment. The postoperative courses were uneventful. They discharged 2 weeks postoperatively without any complications. Blood pressure was nearly normalized at the time of follow up check.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.333-336
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• 2002

In many cases, fuzzy modeling has a defect that the design procedure cannot be theoretically justified. To overcome this difficulty, we suggest a new design method for fuzzy model by combining genetic algorithm(GA) and mush set theory. GA, which has the advantages is optimization, and rule base. However, it is some what time consuming, so are introduce rough set theory to the rule reduction procedure. As a result, the decrease of learning time and the considerable rate of rule reduction is achieved without loss of useful information. The preposed algorithm is composed of three stages; First stage is quasi-optimization of fuzzy model using GA(coarse tuning). Next the obtained rule base is reduced by rough set concept(rule reduction). Finally we perform re-optimization of the membership functions by GA(fine tuning). To check the effectiveness of the suggested algorithm, examples for time series prediction are examined.

• 비파괴검사학회지
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• 제31권6호
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• pp.650-655
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• 2011

Analysis of two-dimensional Rayleigh wave scattering pattern by a surface defect is studied through modified boundary element method. BEM proposed in this paper has special treatment at each end of boundary which should have the Rayleigh wave go away without any generation of virtual reflections. It is shown that treatment for truncated boundary which is used to model two-dimensional Rayleigh waves' behavior in an elastic half-space is successfully implemented. To check numerical results' accuracy, time domain IFFT signal of the displacements is presented. Improvement on getting rid of unwanted influence of truncated boundary induced by 2-D Rayleigh waves on a flat surface of an elastic half-infinite medium is shown. As a final goal, the numerical results of Rayleigh wave scattering trend are plotted and they are compared with theoretical curves to prove its accuracy.

• Journal of Radiation Protection and Research
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• 제34권3호
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• pp.144-150
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• 2009

This study examines how much the radiation dose rate around it varies if a crack occurs on the spent nuclear fuel rod. The spent nuclear fuel rod to be examined is that of Kori unit 3&4. The source terms are evaluated using the ORIGEN-ARP that is part of the version 5.1 of the SCALE package. The radiation dose rate is assessed using the TORT. To check if the structure of a fuel rod is appropriately modeled in the TORT calculation, the calculation results by the TORT are compared with those by the ANISN for the same case. From the code simulation, it is known that if a crack occurs on the spent nuclear fuel rod, the neutron dose rate varies depending on what material is the crack filled with, but the gamma dose rate varies irrespective of type of the material that the crack is filled with.

• Journal of the Korean Data and Information Science Society
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• 제10권2호
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• pp.319-327
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• 1999

영과잉-포아송분포는 여러 형태의 불량률을 줄이는 생산공정과정에서 유용하게 이용되어 왔다. 또한 생산공정과정 중 미지의 변화시점 이후 불량률의 변화가 있는지를 알아보는 것은 흥미 있는 일이고 연구된바있다. 만약 불량품들이 서로 두가지 다른 형태의 규격에 의해 발생되었다면, 이는 일변량이 아닌 이변량 영과잉-포아송 분포를 이용해야 할 것이다. 본 논문은 이변량 영과잉-포아송모형에서 어느 미지의 시점 이후 분포의 변화가 있는지를 우도비 검정을 통해 알아본다. 또한 변화가 있다면 변화시점과 그리고 여러 형태의 모수들에 대한 점추정량을 알아보려 한다.

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.56-62
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• 2014

A tooth with primary endodontic disease that demonstrates a periodontal defect might be extracted because of misdiagnosis as severe periodontal disease or a vertical root fracture. The aim of this case report was to demonstrate the long-term survival of endodontically treated teeth, which had been initially considered unsavable. With meticulous evaluation including the patient's dental history, clinical and radiographic examinations, teeth with primary endodontic lesions could be differentiated and saved after proper root canal treatment. Pain history, vitality test, and radiographic examinations, as well as a general periodontal condition check with periodontal probing on an affected tooth, might be the key methods to differentiate endodontic pathosis from that of periodontal disease.