• 한국콘텐츠학회논문지
• /
• 제16권1호
• /
• pp.42-51
• /
• 2016

오늘날 유통구조의 변화는 오프라인에서 온라인으로 급격하게 수요가 변화해 가고 있다. 이러한 현상은 상품을 편리하게 구입하고자 하는 소비자의 심리가 반영되어 있다고 할 수 있다. 농산물 역시 내용물을 보호하려는 안전성과 소비자들에게 신뢰를 줄 수 있는 브랜드 및 디자인이 어느때보다 중요하게 인식되어지고 있다. 특히, 딸기 과채류는 다른 과채류에 비해 껍질이 얇아서 약한 충격과 흔들림에도 상품의 품질이 떨어지기 때문에 패키지의 지기구조나 소재에 안정성 영향을 많이 받는다. 또한, 직거래 유통이 많은 과채류다보니 생산농가의 열약한 환경 때문에 패키지디자인이 다른 상품에 비해 경쟁력이 떨어지는 것이 현실이다. 즉, 딸기 수요가 날로 증가하는데 비해 딸기패키지는 생산자와 소비자 욕구에 충족하지 못한다는 점이다. 딸기판매에 경쟁력 강화를 위해서는 패키지개발의 기초연구가 시급한 실정이다. 패키지요소(형태, 소재, 디자인) 조사 분석을 통하여 패키지의 문제점을 파악하고, IPA MAP(중요도, 만족도)분석을 통하여 생산자와 소비지가 추구하는 개선점을 파악하고자 한다.

• 한국생활과학회지
• /
• 제17권3호
• /
• pp.541-552
• /
• 2008

With the increase of apartments and expansion of balcony areas, fire safety issues are becoming more important. Many researchers have conducted a lot of researches to reduce vertical flame spread in the balcony when an apartment unit is in fire. However, there have rarely been studies to use balcony area as a space for fire escape and evacuation. The study aims to examine the conditions of balcony use in apartments in order to find out prevention elements from fire escape and evacuation, and to investigate residents' satisfaction with balcony. For this study, questionnaires were collected from apartment residents and workers of architectural planning and construction companies. The findings show as follows: first, the balcony is generally used as a storage in each apartment unit nowadays. Second, when fire breaks out, many storage items could disturb residents' safe escape by blocking escape route, and easily promote to spread flame vertically in the balcony.

• 방사성폐기물학회지
• /
• 제12권2호
• /
• pp.135-151
• /
• 2014

상용의 GoldSim과 GoldSim 이동 모듈 (GoldSim Transport Module; GTM)을 이용하여 방사성폐기물 처분시스템과 같이 복잡한 질량 이동 시스템을 신뢰성 있고 효율적으로 모사할 수 있다. 그러나 GTM의 특성을 보다 정확하게 이해하여야 이를 사용하여 실제 처분시스템의 안전성 평가 프로그램을 개발할 때 발생할 수 있는 오류를 피할 수 있다는 것을 인지하는 것이 중요하다. 이를 위하여 GTM에서 다양하게 제공되는 요소 (element) 중, 질량 이동 모사에 유용한 Transport pathway의 특징에 대하여 소개하고, 방사성폐기물 처분시스템 안전성 평가를 위해 시스템 내 핵종의 거동과 같은 질량 이동 모사에서 이에 대한 올바른 활용 방안을 제시하였다.

• Earthquakes and Structures
• /
• 제9권6호
• /
• pp.1337-1353
• /
• 2015

Seismic upgrading of existing structures is a technical and social issue aimed at risk reduction. Sustainable design is one of the most important challenges in any structural project. Nowadays, many retrofit strategies are feasible and several traditional and innovative options are available to engineers. Basically, the design strategy can lead to increase structural ductility, strength, or both of them, but also stiffness regulation and supplemental damping are possible strategies to reduce seismic vulnerability. Each design solution has different technical and economical performances. In this paper, four different design solutions are presented for the retrofit of an existing RC frame with poor concrete quality and inadequate reinforcement detailing. The considered solutions are based on FRP wrapping of the existing structural elements or alternatively on new RC shear walls introduction. This paper shows the comparison among the considered design strategies in order to select the suitable solution, which reaches the compromise between the obtained safety level and costs during the life-cycle of the building. Each solution is worked out by considering three different levels of seismic demand. The structural capacity of the considered retrofit solutions is assessed with nonlinear static analysis and the seismic performance is evaluated with the capacity spectrum method.

• Structural Engineering and Mechanics
• /
• 제44권4호
• /
• pp.449-463
• /
• 2012

For buildings subjected to blast loading, structural failure can be categorized into local failure (direct blast effects) and progressive collapse (consequential effects). In direct blast effects, the intensive blast pressures create localized failure of structural elements such as exterior columns and walls. Columns, and their behaviour, play a key role in these situations. Therefore investigating the behaviour of columns under blast loading is very important to estimate the strength, safety and reliability of the whole structure. When a building is subjected to blast loading, it experiences huge loading pressures and undergoes great displacement and plastic behaviour. In order to study the behaviour of an element under blast loading, in addition to elastic properties of materials, plastic and elastic-plastic properties of materials and sections are needed. In this paper, using analytical studies and nonlinear time-history analysis by Ansys software, the effects of shape of column sections and boundary conditions, on behaviour and local failure of steel columns under blast load are studied. This study identifies the importance of elastic-plastic properties of sections and proposes criteria for choosing the best section and boundary conditions for columns to resist blast loading.

• 대한지하수환경학회지
• /
• 제1권2호
• /
• pp.100-104
• /
• 1994

기질내에서의 원소의 확산현상은 흡착 및 비흡착성 방사성핵종의 지하매질내 이동을 지연시키는 특성때문에 처분장의 안전성평가에서 매우 중요한 현상으로 간주된다. 이 현상을 실제 안전성평가에 적용하기 위하여 확산현상이 인지되는 자연현상 중에서 자연방사성원소의 농도변화 및 붕괴사슬을 이용한 자연유사 연구가 많이 수행되고 있고 그 현상이 준정량적으로 확인된다. 기질내 원소의 확산현상은 액체상의 흐름에 수반되어 일어나거나 열적 영향에 의해 국부적으로 일어나기도 하는데 후자의 경우는 고준위 방사성페기물 처분과 관련된 안정성평가에 그 중요성을 갖는다. 예를 들어 내덕리 화강암이 후기에 관입한 페그마타이트와 접촉하는 곳에서는 페그마타이트의 열적 영향에 의해 K, Rb, Sr 및 Ba과 같은 알카리 또는 알카리토 원소들과 Li, V및 Nb원소들이 접촉면으로부터 수직으로 약 9 cm 정도의 거리에 이르기까지 부화 또는 결핍된 이동현상이 관찰된다. 그러나 운반모델 설정을 위한 화산시간의 규모, 기질내 흡착된 핵종과 확산된핵종의 구분 등에 관한 연구는 필요한 시료의 취득치 불가능하여 이를 수행하지 못한 경우가 많다 이러한 문제점에도 불구하고 국내 처분장의 안전성 평가시에는 처분매질에 대하여 기질내 확산현상을 어느 정도 고려할 수 있는지를 자연유사 연구를 통해 규명되어야 할 것이다.

• 방사성폐기물학회지
• /
• 제12권1호
• /
• pp.19-35
• /
• 2014

파이로처리 방사성폐기물 처분장에서 폐쇄 후 처분장의 성능에 영향을 줄 수 있는 근계 영역 내 세가지 주요 설계 관련 요소에 대하여 주요 핵종별로 최종 피폭 선량에 주는 민감도를 확률론적인 접근을 통하여 조사하였다. 농축 피폭 집단에 방사선 피폭을 주는 주요한 핵종들이 처분장에서 유출된 후 처분 시스템 근계 영역 내 다양한 매질을 이동하는 것에 관련되어, 이들 요소가 어느 정도의 영향을 주게 되는지 보기 위하여 처분 용기의 수명, 선원항으로서 처분 용기에서의 연간 핵종 유출률, 그리고 처분장 주요 인공 방벽으로서 완충재의 손실도 등의 변화에 따른 결과를 검토하였다. 처분장에 대한 결정론적, 확률론적 안전성 평가를 병행 수행하여, 이 세가지 설계 요소의 물리적 변화가 통계적 분포를 가지고 일어난다고 가정하는 확률론적 접근 방법에 따른 연구 결과는 제 1 부의 이 연구에, 그리고 세가지 설계 요소가 가질 수 있는 조합을 서로 다른 시나리오로서 비교하는 결정론적인 방법으로 접근한 결과는 별도로 제 2 부에 제시하였다. 두 가지 접근 결과와 함께 고려된 인자들에 대하여 모두 결과에 민감한 것으로 나타나 이러한 결과와 방법론은 향후 처분장 설계에 모범적인 피드백을 줄 수 있을 것으로 기대된다.

• 방사성폐기물학회지
• /
• 제18권spc호
• /
• pp.21-36
• /
• 2020

With respect to spent nuclear fuels, disposal containers and bentonite buffer blocks in deep geological disposal systems are the primary engineered barrier elements that are required to isolate radioactive toxicity for a long period of time and delay the leakage of radio nuclides such that they do not affect human and natural environments. Therefore, the thermal stability of the bentonite buffer and structural integrity of the disposal container are essential factors for maintaining the safety of a deep geological disposal system. The most important requirement in the design of such a system involves ensuring that the temperature of the buffer does not exceed 100℃ because of the decay heat emitted from high-level wastes loaded in the disposal container. In addition, the disposal containers should maintain structural integrity under loads, such as hydraulic pressure, at an underground depth of 500 m and swelling pressure of the bentonite buffer. In this study, we analyzed the thermal stability and structural integrity in a deep geological disposal environment of the improved deep geological disposal systems for domestic light-water and heavy-water reactor types of spent nuclear fuels, which were considered to be subject to direct disposal. The results of the thermal stability and structural integrity assessments indicated that the improved disposal systems for each type of spent nuclear fuel satisfied the temperature limit requirement (< 100℃) of the disposal system, and the disposal containers were observed to maintain their integrity with a safety ratio of 2.0 or higher in the environment of deep disposal.

• Geomechanics and Engineering
• /
• 제17권2호
• /
• pp.119-131
• /
• 2019

Time dependent creep settlements are one of the most important causes of material deteriorations for the huge water structures such as concrete faced rockfill dams (CFRDs). For this reason, performing creep analyses of CFRDs is vital important for monitoring and evaluating of the future and safety of such dams. In this study, it is observed how changes viscoplastic behaviour of a CFR dam depending the time. Ilısu dam that is the longest concrete faced rockfill dam (1775 m) in the world is selected for the three dimensional (3D) analyses. 3D finite difference model of Ilısu dam is modelled using FLAC3D software based on the finite difference method. Two different special creep material models are considered in the numerical analyses. Wipp-creep viscoplastic material model and burger-creep viscoplastic material model were rarely used for the creep analyses of CFRDs in the last are taken into account for the concrete slab and rockfill materials-foundation, respectively. Moreover, interface elements are defined between the concrete slab-rockfill materials and rockfill materials-foundation to provide interaction condition for 3D model. Firstly, dam and foundation are collapsed under its self-weight and static behaviour of the dam is evaluated for the empty reservoir conditions. Then, reservoir water is modelled considering maximum water level of the dam and time-dependent creep analyses are performed for maximum reservoir condition. In this paper, maximum principal stresses, vertical-horizontal displacements and pore pressures that may occur on the dam body surface during 30 years (from 2017 to 2047) are evaluated in detail. According to numerical analyses, empty and maximum reservoir conditions of Ilısu dam are compared with each other in detail. 4 various nodal points are selected under the concrete slab to better seen viscoplastic behaviour changes of the dam and viscoplastic behaviour differences of these points during 30 years are graphically presented. It is clearly seen that horizontal-vertical displacements and principal stresses for maximum reservoir condition are more than the empty reservoir condition of the dam and significant pore pressures are observed during 30 years for maximum reservoir condition. In addition, horizontal-vertical displacements, principal stresses and pore pressures for 4 nodal points obviously increased until a certain time and changes decreased after this time.

• 한국기계가공학회지
• /
• 제10권3호
• /
• pp.1-6
• /
• 2011

This study focused on the localization of swivel type tube couplers, which all depend on imports. In this study, a computer application analysis was performed using a finite element method as a preliminary study. In the major developments related to the objective of this study, the air brake system produced by car makers represents a different in the installation point of an air tank according to the type of cars or in the length and direction of its hoses and that leads to cause lots of problems. For solving such problems, the design of the major elements in a swivel type tube coupler was analyzed using a finite element method, and its validity was also verified. In the process that verifies the validity of this study, it was necessary to investigate how much external force affects the desorption of the tube support, which is the most important element in swivel type tube couplers. For achieving the investigation, a pressure test was implemented for the tube support according to the Federal Motor Vehicle Safety Standards(FMVSS). In the results of the pressure test, all samples satisfied the FMVSS. In addition, several tests were implemented by installing the sample of the developed swivel type tube coupler to an actual vehicle. In particular, rotation tests with various angles were applied by welding the swivel type coupler to an air tank through an argon welding process. In the results of the installing test for an actual vehicle, it was verified that the designed structure was determined as a structure that is able to endure the eccentric torque and deformation pressure applied to several directions that are the major problems in such fixed type tube couplers. Therefore, in the comparison of the performance of the developed product with the product of PARKER, it was possible to verify that the localized swivel type tube coupler developed in this study shows more excellent than that of the existing products by PARKER.