• 한국CDE학회논문집
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• 제20권4호
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• pp.367-374
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• 2015

Sandwich panels consisting of various materials have widely been applied for mitigating dynamic impacts such as ballistic and blast impacts. Especially, the selection of materials for different core set-ups can directly influence its performance. In this study, we design the sandwich panels for alleviating ballistic and blast impacts by controlling the stacking sequence of core materials and their thicknesses. FEM studies are performed to simulate the dynamic behavior of sandwich panels subjected to ballistic and blast impacts. Delamination between the core layers is also considered in the FEM studies for feasible design. Based on the FEM data, kriging models are generated for approximating design space and quickly predicting the FEM outputs. Finally, design optimizations are implemented to find the optimum stacking sequence of core materials and thicknesses with given impact situations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.996-999
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• 2010

Aluminium extruded panel is the most important element for sound insulation in a express train. However, comparing with the flat plate with the same weight, the extruded panel shows remarkably low sound transmission loss above the 1st local resonance frequency, which is determined by the dimension of the core structure. Preceding study showed the possibility of the improvement of sound insulation performance by properly designing the core dimension. By the proper core design, local resonance frequency shifts to higher frequency region without any reduction of bending or torsional strength and without any weight increase. Based upon this result, this study investigates in detail the design modification of the core structure of the aluminium extruded panel used in a express train under development, in aspect of sound insulation. Design result is compared with those of other developed models.

• 한국CDE학회논문집
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• 제16권2호
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• pp.156-164
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• 2011

The automation technology is able to enhance the business process more rapidly and effective. Open BIM technology which supports automation technology of building overcomes the limitations of two dimensions drawings system. The purpose of this study is on the development of open BIM based modules for creating and verifying the core model for super-tall building in the schematic design phase. The module is expected to create cases of core models automatically and it is expected to verify the requirement of building model. This module is anticipated to utilize for creating the core model rapidly in order to create the alternative plan and to make the model accurate by its verification.

• 한국지진공학회논문집
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• 제20권5호
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• pp.311-318
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• 2016

The lead-rubber bearing (LRB) dissipates seismic energy through plastic deformation of lead core. Under large-displacement cyclic motion, the temperature increases in the lead core. The shear strength of a lead-rubber bearing is reduced due to the heating effect of the lead core. In this study, the seismic responses such as displacement increasing, shear strength and vertical stiffness degradations of LRB due to the heating effect are evaluated for design basis earthquake (DBE) and beyond design basis earthquake (150% DBE, 167% DBE, 200% DBE).

• 한국콘텐츠학회논문지
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• 제8권9호
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• pp.27-33
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• 2008

Linux에서 사용되는 Shared Memory는 동일한 메모리 영역에 여러 개의 프로세스가 접근할 수 있도록 해 주는 기술이다. 본 논문은 Linux 운영체제에서 지원해 주는 System V의 IPC 중 하나인 Shared Memory를 Dual Core 시스템 상에서 동작하도록 구현한다. 본 논문에서는 커널 단계에서 처리되는 SVR(System V Release) 형식의 Shared Memory를 다룬다. 기존의 공유메모리 방식은 단일 처리기를 이용한 방식이다. 본 논문에서는 dual core를 이용하여 공유메모리 처리를 할 수 있는 시스템을 제안한다. 본 논문에서 제안하는 Dual Core 시스템에서 공유 메모리 기능 구현은 기존의 단일 처리기 시스템에서보다 성능을 향상시킬 수 있도록 한다. 공유 메모리를 이용한 프로세스의 동작이 별개의 CPU에서 동작되도록 함으로써 성능 향상을 꾀한다.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.937-946
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• 2020

The aim in the present work is to simulate accident scenarios of AP1000 during the small-break loss-of-coolant accident (SBLOCA) and investigate the performance and behavior of automatic depressurization system (ADS) during accidents by using MIDAC (The Module In-vessel Degradation severe accident Analysis Code). Four types of accidents with different hypothetical conditions were analyzed in this study. The impact on the thermal-hydraulic of the reactor coolant system (RCS), the passive core cooling system and core degradation was researched by comparing these types. The results show that the RCS depressurization becomes faster, the core makeup tanks (CMT) and accumulators (ACC) are activated earlier and the effect of gravity water injection is more obvious along with more ADS valves open. The open of the only ADS1-3 can't stop the core degradation on the basis of the first type of the accident. The open of ADS1-3 has a great impact on the injection time of ACC and CMT. The core can remain intact for a long time and the core degradation can be prevent by the open of ADS-4. The all results are significant and meaningful to understand the performance and behavior of the ADS during the typical SBLOCA.

• 한국안전학회지
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• 제37권4호
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• pp.129-138
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• 2022

A new method for injecting cooling water into the Korean research reactor (KRR) in the event of beam tube rupture is proposed in this paper. Moreover, the research evaluates the risk to the reactor core in terms of core damage frequency (CDF). The proposed method maintains the cooling water in the chimney at a certain level in the tank to prevent nuclear fuel damage solely by gravitational coolant feeding from the emergency water supply system (EWSS). This technique does not require sump recirculation operations described in the current procedure for resolving beam tube accidents. The reduction in the risk to the core in the event of beam tube rupture that can be achieved by the proposed change in the cooling water injection design is quantified as follows. 1) The total CDF of the KRR for the proposed design change is approximately 4.17E-06/yr, which is 8.4% lower than the CDF of the current design (4.55E-06/yr). 2) The CDF for beam tube rupture is 7.10E-08/yr, which represents an 84.1% decrease compared with that of the current design (4.49E-07/yr). In addition to this quantitative reduction in risk, the modified cooling water injection design maintains a supply of pure coolant to the EWSS tank. This means that the reactor does not require decontamination after an accident. Thermal hydraulic analysis proves that the water level in the reactor pool does not cause damage to the nuclear fuel cladding after beam tube rupture. This is because the amount of water in the chimney can be regulated by the EWSS function. The EWSS supplies emergency water to the reactor core to compensate for the evaporation of coolant in the core, thus allowing water to cover the fuel assemblies in the reactor core over a sufficient amount of time.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 추계학술발표회요약집
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• pp.61-61
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• 1999

• 기술혁신연구
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• 제23권4호
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• pp.177-203
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• 2015

본 연구의 목적은 TV산업에서 지배적 디지털 TV에 영향을 미치는 지배적 디자인 결정요인과 제품핵심요소를 규명하는 것이다. 이를 위하여, 전문가 설문조사를 통해 자료를 수집하고, 구조방정식 모형을 이용하여 분석하였다. 연구 결과, 지배적 디자인의 결정요인은 디스플레이, 디자인, 특성에 영향을 주고 디스플레이와 디자인이 지배적 디지털 TV를 만드는 데 영향을 주는 것으로 밝혀졌다. 본 연구는 우리나라 TV기업이 지속적으로 지배적 디자인을 선도하여 선도자로서의 역할을 유지토록 사업전략 수립의 기초자료로써 큰 의미가 있다 하겠다.

• Geomechanics and Engineering
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• 제10권6호
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• pp.709-726
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• 2016

Corrugated-core sandwich panels are prevalent for many applications in industries. The researches performed with the aim of optimization of such structures in the literature have considered a deterministic approach. However, it is believed that deterministic optimum points may lead to high-risk designs instead of optimum ones. In this paper, an effort has been made to provide a reliable and robust design of corrugated-core sandwich structures through stochastic and probabilistic multi-objective optimization approach. The optimization is performed using a coupling between genetic algorithm (GA), Monte Carlo simulation (MCS) and finite element method (FEM). To this aim, Prob. Design module in ANSYS is employed and using a coupling between optimization codes in MATLAB and ANSYS, a connection has been made between numerical results and optimization process. Results in both cases of deterministic and probabilistic multi-objective optimizations are illustrated and compared together to gain a better understanding of the best sandwich panel design by taking into account reliability and robustness. Comparison of results with a similar deterministic optimization study demonstrated better reliability and robustness of optimum point of this study.