• 한국강구조학회 논문집
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• 제12권3호통권46호
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• pp.251-258
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• 2000

강구조물과 부재들의 지진 손상도 평가법에 새롭게 접근하기 위하여 강한 지진하중을 받는 강재 교각에 대해 수치해석을 수행하였다. 새로운 손상도 평가법에서 파괴 상태에 대한 기준은 지진하중이 재하되는 동안에 응력집중이 가장 심한 단면의 한 부분에서 누적소성변형율의 값이 90%에 이르게 되는 때를 의미한다. 단주기 특성의 지진하중에 대해서는 소성변형율의 누적에 의한 국부좌굴 파괴보다는 허용변위를 초과하는 전체좌굴에 의한 파괴가 지배적인 것으로 밝혀졌다. 장주기 특성의 지진하중에 대해서는 소성변형율이 강재교각 하부의 모서리 부분 요소에 누적되면서 누적 소성변형율에 의한 국부좌굴로 파괴되는 결과를 보였다.

• Steel and Composite Structures
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• 제33권1호
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• pp.37-66
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• 2019

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless-steel lipped channels as compression members are becoming increasingly popular. The advantages of using stainless-steel as structural members are corrosion resistance and durability, compared with carbon steel. The AISI/ASCE Standard, SEI/ASCE-8-02 and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element analyses have been reported in the literature for such back-to back cold-formed stainless-steel channels. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (gAS/NZS) standards for built-up carbon steel sections only describe a modified slenderness approach, to consider the spacing of the intermediate fasteners. Thus, this paper presents a numerical investigation on the behavior of back-to-back cold-formed stainless-steel built-up lipped channels. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404 have been considered. Effect of screw spacing on the axial strength of such built-up channels was investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns, failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines by AISI and AS/NZS. In total, 647 finite element models were analyzed. From the results of the parametric study, it was found that the AISI & AS/NZS are conservative by around 10 to 20% for cold-formed stainless-steel built-up lipped channels failed through overall buckling, irrespective of the stainless-steel grades. However, the AISI and AS/NZS can be un-conservative by around 6% for all three grades of stainless-steel built-up channels, which failed by local buckling.

• 산업노동연구
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• 제24권3호
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• pp.1-34
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• 2018

본 논문은 2010년대 한국의 소득불평등 구조와 그의 변화를 분석하기 위하여 새로운 전체적인(holistic) 이론적 논의를 제시하고 그에 기초한 경험적 분석을 시도한다. 사회학, 노동경제학과 페미니즘에서 이루어진 불평등에 관한 논의는 특정한 영역의 불평등을 중심으로 하는 국지적 불평등에 초점을 맞추었다. 사회 불평등은 국지적 불평등을 넘어서는 전체적인 차원의 불평등에 대한 논의를 필요로 한다. 이는 이들 국지적 불평등을 통합하는 통합적 접근을 필요로 하며, 계급, 노동시장, 인구와 가족 차원의 논의를 포괄한다. 회귀분석 기반 불평등 분해 방법을 활용하여, 전체적 불평등에 영향을 미치는 젠더, 교육, 고용상의 지위, 직업, 가구구성과 재산이 전체 불평등에 기여하는 정도를 분해하여 분석한다. 본 연구는 기존의 국지적 불평등 연구에서 밝혀진 요인들 이외에 기존의 논의에서 간과된 가구 구성과 재산이 소득 불평등에 커다란 영향을 미친다는 점을 밝힌다.

• Earthquakes and Structures
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• 제24권6호
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• pp.393-404
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• 2023

This paper presents the application of hybrid-simulation-based adapter elements for the non-linear two-scale analysis of reinforced concrete frames with masonry infills under seismic-like demands. The approach provides communication and distribution of the computations carried out by two or more remote or locally distributed numerical models connected through the OpenFresco Framework. The modeling consists of a global analysis formed by macro-elements to represent frames and walls, and to reduce global degrees of freedom, portions of the structure that require advanced analysis are substituted by experimental elements and dimensional couplings acting as interfaces with their respective sub-assemblies. The local sub-assemblies are modeled by solid finite elements where the non-linear behavior of concrete matrix and masonry infill adopt a continuum damage representation and the reinforcement steel a discrete one, the conditions at interfaces between concrete and masonry are considered through a contact model. The methodology is illustrated through the analysis of a frame-wall system subjected to lateral loads comparing the results of using macro-elements, finite element model and experimental observations. Finally, to further assess and validate the methodology proposed, the paper presents the pushover analysis of two more complex structures applying both modeling scales to obtain their corresponding capacity curves.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.223-227
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• 2004

The pultruded structural shapes are usually composed of thin-walled plate elements. Because the composite material has relatively low elastic moduli, the design of pultruded compression members may not be governed by the material strength limit state but by the stability limit state such as the local buckling or the global buckling. Therefore, the stability limit state must be checked to design pultruded columns. In this research, the local buckling analysis of pultruded I-shape column was conducted for various composite materials using the closed-form solution. To establish the design guidelines for the local buckling of pultruded I-shape compression members, the simplified form of equation to find the local buckling coefficient of pultruded I-shape column was proposed as a function of mechanical properties and the width ratio of plate components using the results obtainde by the closed-form solution. In order to verify the validity of proposed solution, the results obtained by the proposed approximate solution were compared with those of the closed-form solution and the experimental results.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.159-164
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• 2024

Net surplus serves as a crucial indicator of how efficiently local governments utilize their resources. This study aims to analyze and categorize the patterns of net surplus across 75 local governments in Korea. By employing machine learning techniques such as K-means clustering and silhouette analysis, this research delves into surplus patterns, revealing insights that differ from those provided by traditional analytical methods. Machine learning enables a broader spectrum of discoveries, leading us to identify three distinct clusters in the net surplus of Korean local finances. The characteristics of these three clusters show that the wealthiest cities have the highest surplus ratios. In contrast, mid-sized municipalities, constrained by limited central government support and scarce local resources, exhibit the lowest surplus ratios. Interestingly, a significant number of cities maintain a median surplus ratio even under challenging fiscal conditions. Additionally, we identify critical thresholds that differentiate the three clusters: a grant-in-aid ratio of 19.31%, a debt ratio of 3.52%, and a local tax ratio of 25.58%. This identification of thresholds is a key contribution of our study, as these specific thresholds have not been previously addressed in the literature.

• 한국실내디자인학회논문집
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• 제21권5호
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• pp.399-410
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• 2012

Due to development of modern medical services and economics, people raised expectation and demand about medical services from previous disease treatment to comprehensive health care covering prevention and health care. Responses of each medical facility to these social needs and the evolution of concept of medicine rapidly occur. The health examination centers are being operated with the purpose of health examination and this trend is reflected on several aspects such as the size of the facilities, function and configuration of space in health examination centers. Thus, health examination centers consisting of various space systems appear, but this trend and interpretations are lacking. Therefore, the purpose of this study is to draw trends of system through analysis of types and its evolved space systematic analysis and establish it. Analysis targets were classified into small, medium and large groups by sizes based on number of space and a total of 12 health examination centers in four for each category were selected. As research methods, functional relationship of space was examined through analysis of type in which segmentalized type tools were applied in local units. The flow diagram was established based on direction turning point and was classified into sub-flow and main-flow in local units and the systems between local units were derived. Finally, the results of this study can be summarized as the following three results. 1) The space connection system of health examination center showed four systems such as circulation, independence, continuation, and network. 2) Local type indicators and global type indicators which were evolved more from limitation of type analysis tools in existing research were derived so that more systematic analysis could be made. 3) Network system is distributed approach system and space for each function is formed around public space.

• 정보보호학회논문지
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• 제30권1호
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• pp.141-156
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• 2020

차분 프라이버시는 데이터 프라이버시를 보존함과 동시에 데이터를 수집 및 분석할 수 있는 기법으로써 프라이버시 보존형 데이터 활용 분야에서 널리 적용되고 있다. 이러한 차분 프라이버시의 지역적 모델인 로컬 차분 프라이버시 알고리즘은 무작위 응답을 기반으로 데이터 소유자가 직접 데이터를 가공 처리하여 공개한다. 따라서 개인은 데이터 프라이버시를 보장받을 수 있으며, 데이터 분석가는 수집된 다수의 데이터를 통해 유용한 통계적 결과값을 도출할 수 있다. 이러한 로컬 차분 프라이버시 기법은 세계적 기업인 Google, Apple, Microsoft에서 실질적으로 사용자의 데이터를 수집 및 분석할 때 활용되고 있다. 본 논문에서는 현실에 실질적으로 활용되고 있는 로컬 차분 프라이버시 기법에 대해 비교분석한다. 또한, 실제 적용 사례 연구로써 개인의 프라이버시가 결과의 신뢰성에 큰 영향을 미치는 설문 및 여론조사 시나리오를 기반으로 로컬 차분 프라이버시 기법을 적용하여 현실에서의 활용 가능성에 대해 연구한다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.81.1-81
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• 2003

Although plants have evolved to possess various defense mechanisms from local biotic and abiotic stressors, most of yield loss is caused by theses stressors. Recent studies have revealed that several different stress responsive reactions are inter-networking. Therefore, the identification and dissection of stress responsive genes is an essential and first step towards understanding of the global defense mechanism in response to various stressors. For this purpose, we applied cDNA microarray analysis, because it has powerful ability to monitor the global gene expression in a specific situation. To date, more than 10,000 non-redundant genes were identified from seven different cDNA libraries and deposited in our EST database (http://plant.pdrs.re.kr/ks200201/pepper.html). For this study, we have built 5K cDNA microarray containing 4,685 unigene clones from three different cDNA libraries. Monitoring of gene expression profiles of hot pepper interactions with biotic stress, abiotic stresses and chemical treatments will be presented. Although this work shows expression profiling at the sub-genomic level, this could be a good starting point to understand the complexity of global defense mechanism in hot pepper.

• 대한수학회보
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• 제57권4호
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• pp.1003-1031
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• 2020

We consider the following Dirichlet initial boundary value problem with a gradient absorption and a nonlocal source $$\frac{{\partial}u}{{\partial}t}-div({\mid}{\nabla}u{\mid}^{p-2}{\nabla}u)={\lambda}u^k{\displaystyle\smashmargin{2}{\int\nolimits_{\Omega}}}u^sdx-{\mu}u^l{\mid}{\nabla}u{\mid}^q$$ in a bounded domain Ω ⊂ ℝ^N, where p > 1, the parameters k, s, l, q, λ > 0 and µ ≥ 0. Firstly, we establish local existence for weak solutions; the aim of this part is to prove a crucial priori estimate on |∇u|. Then, we give appropriate conditions in order to have existence and uniqueness or nonexistence of a global solution in time. Finally, depending on the choices of the initial data, ranges of the coefficients and exponents and measure of the domain, we show that the non-negative global weak solution, when it exists, must extinct after a finite time.