• Elastomers and Composites
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• 제54권1호
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• pp.70-76
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• 2019

The function and purpose of the marine rubber fender, to prevent the damage of the ship and the mooring while the ship is being attached to the pier. However, maintenance of the fender after installation is not enough, because it is generally handled as an attachment facility. Estimation the life of a marine rubber fender is important in the maintenance of a port. When manufacturers design and produce marine rubber fenders, they do so according to various conditions such as the reaction force acting on the hull and docking vessel and deformation after absorbing the kinetic energy of the ship. In this study, a method for predicting and evaluating service life from the product design and development stage was established, in order to evaluate the durability of the marine rubber fenders. The SSp-300H and HSP-300H models were used to predict the service life. The method developed in this study, is expected to predict the service life of the marine rubber fender accurately and in a comparatively shorter time, thereby contributing to the evaluation standard and quality stability of the product.

• 한국건축시공학회지
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• 제23권1호
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• pp.57-68
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• 2023

노후화된 건축물이 정상적인 기능을 유지하기 위해서는 주기적인 점검과 보수·보강이 수행되어야 한다. 하지만 현재 건축물 유지관리 단계에서 발생하는 정보의 형태와 의사결정은 여전히 비효율적인 방식에 의존하고 있다. 이는 건축물 유지 관리에서 발생하는 비용의 증가와 시간 낭비의 원인이다. 이에 본 연구는 COBie를 벤치마킹하여 건축물 점검 및 유지보수 정보 관리용 COBie-IM 문서를 제안하고 이를 BIM에 연계하여 정보를 확인하는 방안을 제시하였다. 또한, 건축물에서 발생한 결함의 손상등급에 따라 색상을 지정하여 시각화하는 방안을 제시하였다. 이를 통해 건축물 유지관리 단계에서 점검 및 유지보수 시 발생하는 정보들을 체계적으로 통합·관리하는 것을 목표로 한다. 또한, 결함에 대한 보수·보강의 우선순위를 결정하는 의사결정을 지원함으로써 업무 효율성을 증대시킬 수 있을 것으로 예상된다.

• 한국환경과학회지
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• 제23권8호
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• pp.1523-1536
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• 2014

Restoration is the process of reducing or reversing damage to an ecosystem so that it can function in its original manner. However, many restoration programs do not achieve this. In the Nakdong Estuary, the largest migratory nesting site in the center of the East Asian-Australasian flyway, an estuarine barrage was constructed in the 1980s that required site restoration following its completion in 1987 and the expansion of several large industrial complexes(Noksan and Jangrim) and a residential development(Myeongji). The goal of the restoration was to restore the function of the wetland to its pre-disturbance state. To achieve this, a restoration program was designed consisting of three stages. The first stage(1993-1995), saw the construction of three artificial wetlands(Shinhori, Daemadeung, and Eulsuk), the second(2003-2005) involved the dredging and returning of farmed lands to their natural state, and the third(2008-2012) focused on the rehabilitation and vegetation development of the wetlands. However, the project has not achieved all of the desired goals, and it is an example of the lapses in ecological restoration following anthropogenic disturbance. Issues that resulted in an incomplete restoration included the timing of the stages, noncompliance with the restoration plan, not directly monitoring the restoration or continuing the monitoring following completion of the development project, and the political subversion of the restoration plan. For the success of the restoration plan, it is necessary to avoid mistakes such as inconsistent monitoring, unequal levels of stakeholder involvement, and political interference.

• 대한족부족관절학회지
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• 제24권2호
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• pp.81-86
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• 2020

Purpose: Ankle fractures with dislocations and pilon fractures at the distal tibia are usually associated with soft tissue damage caused by high-energy damage. Recently, a two-stage operation to perform internal fixation after the application of external fixation devices for stabilizing soft tissues has been accepted as the treatment of choice. This paper reports the clinical result of these injuries treated with threaded trans-calcaneal pin external fixation devices. Materials and Methods: Thirty-three patients diagnosed with ankle fractures with dislocations or tibial pilon fractures without open wounds. They underwent surgical treatment with threaded trans-calcaneal pin external fixation from January 2008 to February were enrolled in this study. This study evaluated the visual analogue scale (VAS), foot function index (FFI), and Olerud & Molander score as well as whether complications occurred. Results: The average VAS showed a meaningful decrease (p<0.001) from 7.4 before surgery to 2.6 after application of the external fixation device, and 1.4 at 12 months after surgery. The FFI also decreased significantly from 84.3 preoperatively to 20.3 at 12 months postoperatively (p<0.001). The Olerud & Molander score averaged 71.4 points, showing good clinical results. Complete bone union was observed in all patients. One patient each underwent debridement due to wound necrosis and infection in the pin insertion site. At the final follow-up, seven patients had posttraumatic ankle joint arthritis, according to a radiological examination. Conclusion: Manual reduction and external fixation using a threaded trans-calcaneal pin is a suitable surgical technique that is easy to perform and shows good clinical outcomes in stabilizing soft tissue damage in fractures and dislocations of ankle fracture or tibia pilon fractures in foot and ankle injury.

• 생명과학회지
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• 제16권4호
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• pp.566-570
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• 2006

현재, 유전자의 in vivo 기능을 연구하기 위해 가장 많이 이용되고 있는 transgenic mice를 생산하기 위한 기본적으로 이용되고 있는 방법이 one cell-stage embryo에 pronuclear microinjection (PMI)이다. 그러나, 이 PMI 후에 one cell-stage embryo들의 생존율은 현저히 감소 (65.4%)할 뿐만 아니라 PMI 후의 embryo의 출생률(26.4%)이 PMI 처리를 하지 않은 것 (41.9%) 보다 현저히 낮다. 더욱이, PMI 방법에 의해 태어난 transgenic founder들의 간 조직에 병리학적 변화가 14.8% 정도에 대해서 같은 한배의 새끼 non-transgenic founder들의 경우도 간 조직에 병리학적 변화가 14.3%로 나타났다. 결론적으로, 이 PMI 방법에 의한 염색체에 물리적 손상은 형질전환 마우스의 생산 및 표현형에 영향을 미치는 잠재적 요소로 생각된다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.162-170
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• 2016

Purpose: The purpose of this study was to analyze the failure modes of an auto transfer switch (ATS), determine the most common failure mechanisms, and iterate the design to improve reliability. Methods: We carried out failure mode and effect analysis (FMEA) to determine the failure modes and mechanisms. We identified the parts or modules that required improvement via two-stage quality function deployment based on FMEA, and improvements to reliability were monitored using the Gomperz growth model. Results: The main failure modes of the ATS were damage to, and deformation of, the stator / movable element due to repetitive movements. Five iterations of design modification were carried out, and the mean time to failure (MTTF) increased to 14,539 cycles, corresponding to 85% of the target MTTF. The Gompertz growth model indicates that the 10th iteration of design modification is expected to achieve the target MTTF. Conclusion: We improved the reliability of mechanical parts via failure mode analysis, and characterized the iterative improvements in the MTTF using the Gompertz growth model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.647-652
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• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centro(NS, 1942) ground motion histories with different Peak Ground Acceleration(PGA) ranging from 0.06g to 0.50g. For model updating, flexural stiffness values of structural members(walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions(i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of inputs for updating(i.e. transfer function and natural frequencies). The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters(i.e. flexural stiffness values).

• 한국소음진동공학회논문집
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• 제18권7호
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• pp.725-731
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• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centre (NS, 1942) ground motion histories with different peak ground acceleration (PGA) ranging from 0.06 g to 0.50 g. For model updating, flexural stiffness values of structural members (walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions (i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of Inputs for updating (j.e. transfer function and natural frequencies) The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters (i.e. flexural stiffness values).

• 전기학회논문지
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• 제65권5호
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• pp.836-842
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• 2016

When an accident occurs in the nuclear power plant, the faulted information might mislead to the high possibility of aggravating the accident. At the Fukushima accident, the operators misunderstood that there was no core exposure despite in the processing of core damage, because the instrument information of the reactor water level was provided to the operators optimistically other than the actual situation. Thus, this misunderstanding actually caused to much confusions on the rapid countermeasure on the accident, and then resulted in multiplying the accident propagation. It is necessary to be equipped with the function that informs operators the status of instrument integrity in real time. If plant operators verify that the instruments are working properly during accident conditions, they are able to make a decision more safely. In this study, we have performed various tests for the fault detection sensitivity of an data-driven empirical model to review the usability of the model in the accident conditions. The test was performed by using simulation data from the compact nuclear simulator that is numerically simulated to PWR type nuclear power plant. As a result of the test, the proposed model has shown good performance for detecting the specified instrument faults during normal plant conditions. Although the instrument fault detection sensitivity during plant accident conditions is lower than that during normal condition, the data-drive empirical model can be detected an instrument fault during early stage of plant accidents.

• Nuclear Engineering and Technology
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• 제21권1호
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• pp.1-11
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• 1989

원자로 정지동안에도, 잔열제거계통은 그 기능이 계속 유지되어야 하나, 실제로 가압 경수로에서 냉각상실고가 많이 발생되어 있다. 본 논문은 원자로 정지중의 냉각기능상실을 예방하고, 또한 냉각기능상실로 인한 노심손상의 중대성을 완화시키기 위한 대책을 강구하기 위한 시도로서, 전형적인 가압경수로에 대한 사고/고장 수목과 운전원실수 확률을 위한 HCR 모델, 초기 사상의 빈도를 위한 2단계 bayesian 방법 및 고장난 계통의 회복 활률을 위한 계단함수 모델 등을 이용한 원자로 정지 위해도 모델을 개발하여, 잔열제거계통의 신뢰도를 분석하였다. 그 결과는 원자로가 정지 중일 때의 위해도가 운전중일 때 이것에 비해 별로 낮지 않은 것으로 나타났으며, 몇 가지의 설계개선을 통하여 냉각기능상실로 인한 노심 손상확률을 상당히 낮출 수 있는 것으로 나타났다.