• Nuclear Engineering and Technology
• /
• 제42권5호
• /
• pp.582-589
• /
• 2010

As a part of the back-end fuel cycle, transportation of spent nuclear fuel (SNF) from nuclear power plants (NPPs) to a fuel storage facility is very important in establishing a nuclear fuel cycle. In Korea, the accumulated amount of SNF in the NPP pools is troublesome since the temporary storage facilities at these NPP pools are expected to be full of SNF within ten years. Therefore, Korea cannot help but plan for the construction of an interim storage facility to solve this problem in the near future. Especially, a decision on several factors, such as where the interim storage facility should be located, how many casks a transport ship can carry at a time and how many casks are initially required, affect the configuration of the transportation system. In order to analyze the various possible candidate scenarios, we assumed four cases for the interim storage facility location, three cases for the load capacity that a transport ship can carry and two cases for the total amount of casks used for transportation. First, this study considered the currently accumulated amount of SNF in Korea, and the amount of SNF generated from NPPs until all NPPs are shut down. Then, how much SNF per year must be transported from the NPPs to an interim storage facility was calculated during an assumed transportation period. Second, 24 candidate transportation scenarios were constructed by a combination of the decision factors. To construct viable yearly transportation schedules for the selected 24 scenarios, we created a spreadsheet program named TranScenario, which was developed by using MS EXCEL. TranScenario can help schedulers input shipping routes and allocate transportation casks. Also, TranScenario provides information on the cask distribution in the NPPs and in the interim storage facility automatically, by displaying it in real time according to the shipping routes, cask types and cask numbers that the user generates. Once a yearly transportation schedule is established, TranScenario provides some statistical information, such as the voyage time, the availability of the interim storage facility, the number of transported casks sent from the NPPs, and the number of transported casks received at the interim storage facility. By using this information, users can verify and validate a yearly transportation schedule. In this way, the 24 candidate scenarios could be constructed easily. Finally, these 24 scenarios were compared in terms of their operation cost.

• 한국음향학회지
• /
• 제33권5호
• /
• pp.341-350
• /
• 2014

본 논문에서는 수중음향 센서 네트워크에서 자기 조직화 기법을 활용하는 에너지 효율적 클러스터링 기법을 제안한다. 제안 기법은 클러스터 헤드 선출에 각 노드의 배터리 잔여량 정보와 이웃 노드의 수를 고려하며, 클러스터 헤드의 배터리 잔여량이 특정 수준 이하로 떨어졌을 경우에만 클러스터 재구성을 수행함으로써 노드의 에너지 소모를 줄이고 네트워크 전체에 에너지 소모를 분산시켜 네트워크의 수명을 연장시킬 수 있다. 또한, 클러스터 헤드는 클러스터 멤버 노드로부터 수집한 데이터를 다중 홉 중계 방식으로 싱크 노드에 전송하여 에너지 소모를 줄인다. 컴퓨터 모의실험을 통해, 일정 시간 경과 후 전체 노드의 배터리 잔여량의 합, 생존 노드의 수, 네트워크 구성 단계에서의 에너지 소모량, 전체 노드의 에너지 소모 편차 등을 구하고 대표적 클러스터링 기법 중의 하나인 LEACH 기법과 비교 및 분석한다. 모의실험 결과, 제안 기법이 LEACH 기법에 비해 네트워크 운용 시간을 두 배 향상시킬 수 있으며, 전체 노드의 에너지 소모 편차 또한 감소시킴을 알 수 있다.

• 한국산학기술학회논문지
• /
• 제18권9호
• /
• pp.403-410
• /
• 2017

국내의 공동주택은 1980년대 후반에 시행된 주택공급정책으로 급속히 증가하였으나, 물량적 보급에만 치중하고 품질관리측면에서는 상대적으로 소홀히 하여 다양하고 많은 하자가 발생하게 되었다. 그리고 다양하고 많은 하자 발생에 따른 분쟁이 점점 부각되고 있으며, 다양한 문제점들을 해결하기 위하여 공동주택 하자 관련 연구들이 지속적으로 수행되어 왔다. 이에 본 연구에서는 키워드 네트워크 분석 방법론을 활용하여 오랜 기간 축적된 공동주택 하자 관련 연구 분야의 주요 키워드 및 트렌드를 분석하여 시사점을 도출하고자 하였다. 연구 분석 방법으로는 한국교육학술정보원 포털을 활용하여 학술지 논문을 수집하고, 수집된 학술논문의 필터링 및 키워드 정제과정을 거쳐 분석자료를 구축하였다. 그리고 키워드 네트워크 관계에 대한 시각화 모델링, 연결정도 중심성 분석, 매개 중심성 분석을 실시하였다. 연결정도 및 매개 중심성 분석 결과, 담보, 논쟁, 수리, 사례, 책임, 결로, 비용, 제도, 기준, 감정이 공동주택 하자 분야에 특징적으로 나타나는 주요 키워드로 분석되었다.

• Environmental Engineering Research
• /
• 제20권3호
• /
• pp.246-253
• /
• 2015

The effects of carbon-to-nitrogen (C/N) ratio in simulated rice straw hydrolysates using glucose and ammonium chloride on polyhydroxyalkanoates (PHA) accumulation by Cupriavidus necator was investigated. In general, PHA accumulation rate was higher under higher degrees of N-deficient conditions (e.g., C/N ratio of 360:1) than lower degrees of N-deficient conditions (e.g., C/N ratio of 3.6:1 and 36:1). Also, the most PHA accumulation was observed during the first 12 h after the PHA accumulation initiation. This study showed that the similar PHA accumulation could be achieved by using different accumulation periods depending on C/N ratios. N source presence was important for new cell production, supported by approximately ten times greater PHA accumulation under the N-deficient condition ($NH_4Cl$ 0.01 g/L) than the N-free (without $NH_4Cl$) condition after 96 h. C/N ratio of the rice straw hydrolysate was approximately 160:1, based on the glucose content, and this accumulated $0.36{\pm}0.0033g/L$ PHA with PHA content of $21{\pm}3.1%$ after 12 h. Since external C or N source addition for C/N ratio adjustment increases production cost, an appropriate accumulation period may be used for PHA accumulation from organic wastes, based on the PHA accumulation patterns observed at various C/N ratios and C and N concentrations.

• 한국산학기술학회논문지
• /
• 제19권8호
• /
• pp.64-70
• /
• 2018

무기 체계(or 구성품) 개발은 한정된 개발기간과 비용 등의 제한으로 시험 횟수가 많지 않아, 고장관련 축적된 데이터의 규모도 적다. 그러나 운용 중 발생한 고장 및 정비내역은 많은 부분 전산 데이터로 관리하고 있기 때문에 이를 활용한 무기 체계(or 구성품)의 고장원인 분석은 가능하다. 다만 다양한 무기체계의 고장 및 정비내역 작성 규격이 각 군 별, 업체별 상이하고, 고장 원인의 구체적 내역은 비정형 텍스트 데이터로 기술되어 있기 때문에 이를 분석하는데 어려움이 있었다. 그러나 오늘날 빅데이터 처리 기술과 기계학습(Machine Learning) 알고리즘의 발전, HW연산 능력의 개선과 맞물려, 상기와 같은 비정형 데이터를 처리 할 수 있는 여러 가지 방법들이 시도 되고 있으며, 주요한 연구 분야로 활발히 연구되고 있다. 본 논문에서는 국방 무기 체계(or 구성품)의 고장/정비 관련 비정형 데이터를 기계학습 기법 중 하나인 doc2vec을 적용하여 고장사례 분석 방안에 대하여 제시한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
• /
• pp.2195-2196
• /
• 2006

This study is for implementation of PC based Motor fault diagnosis system. By using harmonics and current signals of the motor, this system diagnoses the motor condition by accumulated harmonic contribution rate. In this proposed system that was composed of 5 parts. A sensor, connection box, evaluation board, device server, and main computer are those. There were two types of sensor, one was harmonic sensor the other was current sensors. The signal was acquired by sensor, and transferred to evaluation board. Second one is connection box. Because the output type of sensor and input type of evaluation board is different, connection box was necessary. Third one was evaluation board. The signal from the sensor was converted to digital signal in evaluation board. And this signal was transferred to device server. Fourth one was device server. Device server transferred the data from evaluation board to main computer. And the last one was other parts controlled by main computer. In main computer, there were communication and diagnosis algorithms. The result was derived by main computer. In the result, there were 12 categories and 5 levels of motor conditions. The proposed system had some advantages comparing with stand alone type commercial motor fault diagnosis system. The first, by using remote access it was easier to get the conditions of motor. The second, there was no need to handle the sensors when users measured the motor signals. By this property, no one was necessary at motor location site. The third, this system was less restricted by times and places than commercial stand alone type diagnosis system. Therefore users can operate this system only using the main computer. Once the sensors are installed at the motor, users doesn't need to move to check up the condition of motors. Moreover, if there is ethernet hub, many motors can be not only diagnosed at once but also decreased its cost.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
• /
• pp.563-564
• /
• 2006

This study is for implementation of PC based Motor fault diagnosis system. By using harmonics and current signals of the motor, this system diagnoses the motor condition by accumulated harmonic contribution rate. In this proposed system that was composed of 5 parts. A sensor, connection box, evaluation board, device server, and main computer are those. There were two types of sensor, one was harmonic sensor the other was current sensors. The signal was acquired by sensor, and transferred to evaluation board. Second one is connection box. Because the output type of sensor and input type of evaluation board is different, connection box was necessary. Third one was evaluation board. The signal from the sensor was converted to digital signal in evaluation board. And this signal was transferred to device server Fourth one was device solver. Device server transferred the data from evaluation board to main computer. And the last one was other parts controlled by main computer. In main computer, there were communication and diagnosis algorithms. The result was derived by main computer. In the result, there were 12 categories and 5 levels of motor conditions. The proposed system had some advantages comparing with stand alone type commercial motor fault diagnosis system. The first, by using remote access it was easier to get the conditions of motor. The second, there was no need to handle the sensors when users measured the motor signals. By this Property, no one was necessary at motor location site. The third, this system was less restricted by times and places than commercial stand alone type diagnosis system. Therefore users can operate this system only using the main computer. Once the sensors are installed at the motor, users doesn't need to move to check up the condition of motors. Moreover, if there is ethernet hub, many motors can be not only diagnosed at once but also decreased its cost.

• 한국철도학회논문집
• /
• 제17권1호
• /
• pp.52-58
• /
• 2014

노반 성토체에서 발생하는 소성 변형은 콘크리트 궤도의 안정성과 유지보수에 영향을 미친다. 철도 노반에서의 장기적인 소성 변형은 주로 반복적인 열차 통과로 발생하는 누적된 비탄성적 변형률에 의해 발생한다. 누적 소성 변형의 예측은 궤도의 유지보수와 열차의 안전한 운영을 위해서 중요하다. 본 연구에서는 서로 다른 강화노반 두께를 가진 철도노반에서 발생하는 연직 변위를 계산하였다. 누적 소성 변형률을 계산하기 위한 멱함수의 상수는 삼축 실험과 실대형 재하 실험의 결과로부터 구하였다. 표준 노반 단면에 대한 3차원 유한요소해석 결과로부터 강화노반의 두께를 선정하는 가이드라인을 제시하였다.

• 정보화정책
• /
• 제20권4호
• /
• pp.71-88
• /
• 2013

높은 불확실성을 특징으로 하는 탈추격 단계에서는 기술위험의 가능성도 높아진다. 온라인게임은 새로운 기술 수명주기를 창조한 탈추격형 혁신의 결과물이다. 하지만 온라인 게임 중독이라는 부작용이 나타나면서 셧다운제 도입이 결정되었지만 규제 찬성과 반대집단간의 논란은 계속되고 있다. 기술위험은 사회적 맥락과 조건의 영향을 받는다. 온라인게임 중독을 초래한 사회기술적 취약성은 역설적이게도 우수한 정보화 인프라와 정보통신기기의 확산이었다. 기술위험의 원인이 된 취약성은 위험을 무시하는 발전주의 사고에 의해 더욱 강화되었다. 온라인게임 중독과 같은 기술위험을 해결하기 위해서는 우선 기술혁신의 편익과 기술위험 간의 딜레마를 인지해야 한다. 딜레마 인식의 실패는 사회적 비용을 유발하며 문제해결을 위한 노력을 어렵게 한다. 탈추격단계로의 진입에 따라 기술위험은 더욱 증가할 것이라는 점에서 이런 딜레마를 인지하고 교정책임의 적절한 부과, 해체와 재규정을 통한 딜레마의 관리, 토론장치의 설계, 사회적 책임과 경제적 성공의 연결 등을 통해 기술혁신의 책임성 확보를 위한 해결책의 모색이 필요하다.

• Advances in aircraft and spacecraft science
• /
• 제4권5호
• /
• pp.515-528
• /
• 2017

Since composite structures are widely used in structural engineering, delamination in such structures is an important issue of research. Delamination is one of a principal cause of failure in composites. In This study the electrical potential (EP) technique is applied to detect and locate delamination in basalt fiber reinforced polymer (FRP) laminate composite pipe by using electrical capacitance sensor (ECS). The proposed EP method is able to identify and localize hidden delamination inside composite layers without overlapping with other method data accumulated to achieve an overall identification of the delamination location/size in a composite, with high accuracy, easy and low-cost. Twelve electrodes are mounted on the outer surface of the pipe. Afterwards, the delamination is introduced into between the three layers (0º/90º/0º)s laminates pipe, split into twelve scenarios. The dielectric properties change in basalt FRP pipe is measured before and after delamination occurred using arrays of electrical contacts and the variation in capacitance values, capacitance change and node potential distribution are analyzed. Using these changes in electrical potential due to delamination, a finite element simulation model for delamination location/size detection is generated by ANSYS and MATLAB, which are combined to simulate sensor characteristic. Response surfaces method (RSM) are adopted as a tool for solving inverse problems to estimate delamination location/size from the measured electrical potential changes of all segments between electrodes. The results show good convergence between the finite element model (FEM) and estimated results. Also the results indicate that the proposed method successfully assesses the delamination location/size for basalt FRP laminate composite pipes. The illustrated results are in excellent agreement with the experimental results available in the literature, thus validating the accuracy and reliability of the proposed technique.