• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.69-74
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• 2003

Recent deepwater offshore structures in the Gulf of Mexico utilize butt welded tubular joints. Application of a welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical, as the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimation of the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves, as specified in the codes and standards. Applying the stress concentration factor of the welded structure to the S-N approach often results in a very conservative assessment, because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fatigue life analysis using fracture mechanics has been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. Still, there is inconsistency when designing tubular joints using a conventional S-N approach and when specifying weld flaw acceptance criteria using fracture mechanics approach. This study developed fatigue curves that are consistent with both the S-N approach and the fracture mechanics approach. Accounting for non-uniform stress distribution and threshold stress intensity factor were key parameters in relating both approaches. A series of S-N curves, generated from the fracture mechanics approach, were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02). The new curves for tubular joint agree very well with the experimental results. The comparison also indicated the degree of conservatism built into the API X design curve.

• 조명전기설비학회논문지
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• 제17권2호
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• pp.102-108
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• 2003

본 논문에서는 SDAS(Signal Data Acquisition System)를 설계하여 정밀도와 응답특성을 향상시킨 새로운 정보취득장치를 제안한다. 원자력 발전소에 적용되는 계측제어 시스템은 안전에 직접 또는 간접적으로 영향을 미치는 장치이므로 이들 기기는 안전등급의 분류에 따라 기기 검증의 절차에 의하여 현장 적용 이전에 주요 제어 설비가 설계명수 기간동안에 의도된 기능을 수행할 수 있음이 검증되어야 한다. 본 논문에서는 국제 기준 규격인 IEEE 규격과 Nuclear Regulatory Guide의 규격에 명시되어 있는 성능시험방법과 절차에 의한 기기검증에서 필수적인 장비인 정보취득장치를 제안하였고, 기존에 사용되고 있는 정보취득장치와 성능을 비교 분석하였다. 이론과 실험적인 연구가 수행되었고, 그 결과는 제안된 정보취득장치의 정밀도 성능이 개선되었음을 입증한다. 따라서 제안된 시스템은 고성능 계측제어시스템에 적용될 수 있다.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.52-57
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• 2005

The increasing automobiles continue to cause air-pollution problem s worse than ever. In fact, many automobile research are involved in how to reduce exhaust emissions effectively specially in $NO_X$ and PM to comply with stringent emission standards, Euro V. This research emphasized on the development of continuous regeneration DPF technology which was one of promising removing technology of particulate matters because of its comparability and high applicability. In addition, this research discussed on some design points of view through correlation study by com paring the experimental data with computational results by the introduction of commercial codes such as CFD-ACE+ and KIVA-3V. The numerical simulation on the performance of continuous regeneration DPF apparatus and corresponding emission characteristics has been predicted well enough and verified with experimental results. The pressure and average temperatures are decreased to about 2.6% and 1.4% respectively under a full engine load condition mainly due to back pressures raised by diesel particulate filter. Pressure, temperature and heat releasing rates tend to decrease specially at higher engine load, but they are not affected at lower engine load regions.

• 한국구조물진단유지관리공학회 논문집
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• 제24권6호
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• pp.197-205
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• 2020

주택법(2014년)에 근거하여 철근콘크리트 공동주택의 리모델링 시 수직 및 세대수 증축이 가능하게 되었다. 수직증축 리모델링 가능 여부는 안전진단 기준 및 매뉴얼을 바탕으로 기울기 및 침하, 내하력, 내구성 평가 부문에 대한 평가를 통하여 판정하도록 되어 있다. 그러나 증축형 리모델링 기준 및 매뉴얼 제정 당시, 국내에서는 수직증축 리모델링 안전진단 사례가 전무하여 평가기준 등에 대한 공학적 근거 제시에 한계가 있었으며, 특히 내구성 평가 기준에 대한 합리화 및 관련 기준과의 부합을 위한 개선이 필요한 것으로 생각된다. 따라서 본 연구에서는 국내외 내구성 관련 기준을 근거로 콘크리트 탄산화, 염분함유량, 균열, 철근부식, 표면노후도의 허용치와 평가기준에 대한 검토·분석을 통하여 수직증축형 리모델링 안전진단 내구성 평가방법의 합리화 방안을 제시하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.127-132
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• 2002

Recent deepwater offshore structures in Gulf of Mexico utilize butt welded tubular joints. Application of welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical because the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimating the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves specified in the codes and standards. Applying the stress concentration factor of the welded structure to S-N approach often results in very conservative assessment because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fracture mechanics and fitness for service (FFS) technology have been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves to be used and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. An attempt was made to develop set of S-N curves based on fracture mechanics approach by considering non-uniform stress distribution and a threshold stress intensity factor. Series of S-N curves generated from this approach were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02"). Similar comparison with API X′ was made for tubular joint.. These initial crack depths are larger than the limits of inspection by current Non-destructive examination (NDE) means, such as Automatic Ultrasonic Inspection (AUT). Thus a safe approach can be taken by specifying acceptance criteria that are close to limits of sizing capability of the selected NDE method. The comparison illustrates conservatism built into the S-N design curve.

• 대한물리의학회지
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• 제11권3호
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• pp.111-118
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• 2016

PURPOSE: The aim of this study was to examine the ethical values of physical therapy. This study was launched to establish a foundation for this field of study by gathering data about current topic of ethical values in the field of physical therapy. METHODS: This investigation was conducted with 900 students from seven different universities in the Republic of Korea (three, four-year colleges. The methodology of this research was directed at revamping and supplementing ethical codes in the Korean Physical Therapy Association and establishing a set of ethics-related questions as inspired by the studies conducted by Youk and Choi. Each question was assigned a different point-value according to the standards of measurement that we established. RESULTS: The scores of participants and their sibling status, it appears that whether participants had siblings did significantly impact their ethical outlook. The scores based on sibling one and two siblings, more than three siblings, no sibling were 29.42, 29.03, 28.25, and 28.19, respectively (p<.05). But in examining the average ethics scores with regards to reported past experiences with ethics education, we can see that past experience significantly impacted the results of the study on medical ethics perceptions. The scores corresponding to responses that one did or did not have prior experience were 29.40 versus 28.99. CONCLUSION: It is crucial to assure that physical therapy students receive well-founded information and proper ethical value. We suggest that create an ethics education program to enhance physical therapists and physical therapy students.

• 전자공학회논문지CI
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• 제43권4호
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• pp.73-79
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• 2006

터보 코드는 강력한 에러정정 성능 때문에 W-CDMA(Wideband Code Division Multiple Access), CDMA2000 등의 통신 알고리즘에 적용되고 있으며, 여러 분야에서 하드웨어로 구현되어졌다. 여러 가지의 개선 알고리즘과 하드웨어 구조가 제안되어 졌으나 아직까지 하드웨어 면적, 동작속도 및 소비전력 등의 문제가 연구되어지고 있다. 본 논문에서는 하드웨어 면적과 동작속도를 향상시키기 위하여 사후확률 최적화로부터 유도된 MAX-SCALE 알고리즘을 이용한 터보코드 복호기를 설계하였으며, 제안된 회로는 Matlab과 MaxPulsII를 사용하여 성능 측정 및 FPGA 보드상에 구현되었다. 결과적으로 제안된 구조를 사용하여 FPGA에 구현했을 때, 616개의 로직 요소 (Logic Element)를 가지며 MAP(Maximum a Posteriori) 복호 알고리즘에 비해 동작속도는 56.48MHz로 약 40% 향상되었으며, 6.12%의 BER(Bit Error Rate) 성능이 향상되었다.

• 정보과학회 논문지
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• 제42권11호
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• pp.1349-1360
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• 2015

소프트웨어 품질을 향상하기 위해서는 소스에 내재된 결함을 효율적, 효과적으로 제거해야 한다. 개발현장에서는 결함 심각도와 결함 제거율로 결함을 제거하고 있다. 결함을 이용하여 품질을 향상하기 위한 연구로는 결함 발생 빈도과 ISO 품질속성을 이용하여 품질을 향상하려는 연구가 있고, 프로젝트 수행 시 결함을 심각도로 관리하여 품질을 향상시키는 연구가 있었다. 하지만, 결함 자체에 집중하여 결함을 유형화하여 결함 유형 간에는 어떤 영향력이 있는지, 그 영향력으로 인하여 어느 결함 유형이 더 중요한 지에 대한 연구는 미흡한 실정이었다. 이에 본 연구에서는 표준단체, 업체, 연구자들의 소프트웨어 결함 유형을 수집, 분류하여 ANP로 모형화하였다. 또한, 구성된 ANP 모형을 이용하여 일반 응용 소프트웨어에 대하여 결함 유형별 중요도 가중치를 산정하였다. 일반 응용 소프트웨어를 개발할 때, 산정된 가중치를 적용하여 결함을 제거한다면, 좀 더 효율적이고 효과적으로 소프트웨어 품질을 향상할 수 있으리라 기대한다.

• Wind and Structures
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• 제27권3호
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• pp.163-173
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• 2018

The design wind pressure for low-rise buildings in the ASCE 7-10 is defined by procedures that are categorized into the Main Wind Force-Resisting System (MWFRS) and the Components and Cladding (C&C). Some of these procedures were originally developed based on steel portal frames of industrial buildings, while the residential structures are a completely different structural system, most of which are designed as low-rise light-frame wood constructions. The purpose of this study is to discuss the rationality (or irrationality) of the extension of the wind loads calculated by the ASCE 7-10 to the light-frame wood residential buildings that represent the most vulnerable structures under extreme wind conditions. To serve this purpose, the same approach as used in the development of Chapter 28 of the ASCE 7-10 that envelops peak responses is adopted in the present study. Database-assisted design (DAD) methodology is used by applying the dynamic wind loads from Louisiana State University (LSU) database on a typical residential building model to assess the applicability of the standard by comparing the induced responses. Rather than the postulated critical member demands on the industrial building such as the bending moments at the knee, the maximum values at the critical points for wood frame buildings under wind loads are used as indicators for the comparison. Then, the critical members are identified through these indicators in terms of the displacement or the uplift force at connections and roof envelope. As a result, some situations for each of the ASCE 7 procedures yielding unconservative wind loads on the typical low-rise residential building are identified.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.339-349
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• 2013

The primary purpose of this research was to set up the standard guidelines for the planning of interior architectural environments of the detention facilities at the Korean Police Stations. By visit-studying the actual interior environmental conditions of 5 different kinds' domestic Correcting Facilities and 5 domestic police detention facilities and 2 foreign police detention facilities, comparing them to the existing Korean correctional institutions' cell facilities, that the strengths and weaknesses had been analyzed to extract the main concepts and the planning scheme for the Standard Korean Police Detention Facilities. By reserching the National human Right Commitee's Anual Reports, three different indexes were picked out for those analysis : the Environmental control index, the Detention Service support index, the Environmental support index. These three indexes will be used as Key factors for the planning of interior architectural environments of the detention facilities at the Korean Police Stations.: (1)the Environmental control index to establish the Space Program, the Spatial Hierarchy and the horizontal & vertical Security Blocks, (2)the Detention Service support index for the central Environmental Control & Security System, the Secured Privacy for both detainees & police offices, (3)the Environmental support index for the gender-respected segregation of cell zones, the psychological & physical safety design factors, the construction standards of all rooms in a detention facility. The result of this study should be used as the guidelines for "The Standard Plans and Regulations for the Korean Police Detention Facilities" to respect fundamental human rights.