• Title/Summary/Keyword: 구조적 붕괴

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The Entrepreneurial Factors and Entrepreneurial Intention on Student (대학생의 창업요인과 창업의지와의 관계 연구)

  • Kim, Hong
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.7 no.1
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    • pp.263-271
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    • 2012
  • The purpose of this study is to investigate the relationship between entrepreneurial factors and entrepreneurial intention on student. This study is designed to examine the effect of entrepreneurial factors on entrepreneurial intention. Data for the study was compiled through surveys on 300 students who study in engineering school of H university. Empirical results of the hypothesis testing are summarized as follows: The results indicate that both two variable groups have positively influenced the entrepreneurial factors was highly related to entrepreneurial intention. The factors entrepreneurship are background, individual and situational factor. This all factors influence on entrepreneurial intention. The entrepreneurial factors had a positively influence on will power of entrepreneur. The entrepreneurial factors had a positively influence on performance of entrepreneur.

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Self-assembly of Retinoic Acid-conjugated Poly(Amino Acid)'s Derivative (레티노익산이 접목된 폴리아미노산 유도체의 자기조립 현상)

  • Han, Sa Ra;Lee, Hyeongyeong;Kim, Hee-Jin;Cho, Yoon Na;Lee, Seung-Jun;Zhoh, Choon-Koo;Jeong, Jae Hyun
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.42 no.4
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    • pp.433-440
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    • 2016
  • In this study, a poly (amino acid)s derivative grafted with retinoic acids, which could form self-assemblies in an aqueous solution, was successfully synthesized. The synthesized amphiphilic poly (amino acid)s were controlled with 5, 10, 30 mol% substitution of retinoic acid. Then, the amphiphilic poly (amino acid)s were self-assembled by inter/intra molecular stacking of retinoic acids in an aqueous solution. Also, the increasing the degree of substitution (DS) of retinoic acids decreased the size of self-assembled nanoparticles and induced structural transition to bilayer structure from spherical structure. The retinol was stably encapsulated into a core of self-assembled nanoparticle with 10 mol% of DS. This strategy to prepare the self-assemblies of amphiphilic polyaspartamide will serve to improve the efficiency of targeted delivery for a functional cosmetic with various biological modalities.

Numerical Simulation on the Steel Plate Cutting Performances of Bent-Shaped Charge Holder Blasting (드로잉 가공 성형폭약용기의 강판절단성능에 관한 수치해석적 연구)

  • Min, Gyeong-Jo;Park, Hoon;Oh, Se-Wook;Park, Se-Woong;Suk, Chul-Gi;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.36 no.3
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    • pp.19-28
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    • 2018
  • Locally damaged structures caused by earthquake or extraordinary external forces have been required to rapidly be dismantled because of its possibility of additional collapses. Particularly, steel frame structures were demolished by the shaped charge blasting method. Recently a research suggested a shape charge blasting technique which uses bent-shaped charge holder of copper plate and emulsion explosive charge to cut thick steel plates. This study simulated the cutting performance of the bent-shaped charge holder with considering types of explosives, thickness of copper liner and stand-off distances using LS-DYNA software. The shape charge blasting test of a 25mm thickness steel plate were used to calibrate the input parameters of the numerical models. The penetration depth and penetration width were analysed with different types of explosives, thickness of copper liner and stand-off distances.

Analysis and Reinforcing Method of Greenhouse Frame for Reducing Heavy Snow Damage (단동온실의 설해 경감을 위한 해석 및 보강방법연구)

  • Park, Soon-Eung;Lee, Jong-Won;Lee, Suk-Gun;Choi, Jae-Hyouk
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.4
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    • pp.1-7
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    • 2010
  • Recently, the damage of the farmhouse has been increased due to frequent collapsing accidents of the pipe greenhouse caused by the heavy snow load derived from unusual weather phenomena. However, the study about it is rare and tenuous so that the damage is happened repeatedly. Although there are a few ways to improve the greenhouse such as increasing section, decreasing the distance between rafters in order to avoid the collapsing accidents, those ways have some shortcomings like cost and frame ratio increase, etc. Therefore, this study performed the large displacement analysis considering geometric non-linearity on each load level with respect to many kind of reinforcement methods and analyzed combined strength ratio and stress so as to search the ways, which enhance the structural stability of greenhouse and minimize the frame ratio increase. As a result, this paper is aimed at suggesting the optimal reinforcement method model.

A Study on Assessment Techniques of Levee Safety (하천제방의 안전성 평가기법 연구)

  • Yoon Jong-Ryeol;Kim Jin-Man;Choi Bong-Hyuck
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.111-116
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    • 2005
  • 2-D and 3-D resistivity surveys were carried out at the Deok-In2 levee during the period of arid and rainy seasons to assess the waterproof effectiveness of sheet pile and grouting sections and detect the location of pipings. Inverted resistivity sections clearly indicated the boundaries of sheet pile and grouting sections and the locations of pipings observed at the ground surface. Besides, GPR survey was carried out to verify the rear cavity of culvert in levee which is thought to be the major cause of levee breakdown, But the quality of GPR data was very poor due to the steel reinforcements buried in the culvert. Because it is not easy to apply various geophysical surveys upon concrete structures, newly designed hydraulic response test was proposed to assess the continuity of rear cavity of culvert in this study.

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A Stability Analysis for Vehicle Impact in U-Channel Segmental Concrete Bridges (U-채널 세그멘탈 콘크리트 교량의 차량충돌에 대한 안전성 분석)

  • Choi, Dong-Ho;Na, Ho-Sung
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.17-25
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    • 2010
  • This paper studied on stability of the U-channel segmental concrete bridge under vehicle-impact loads. The U-channel bridge has advantages in that it reduces an additional dead load and the edge beams role as a barrier. But it has a dangerous factor which collapses the bridge structure when the edge beams are ruptured. Therefore, it is necessary to verify behaviors of the bridge system under vehicle-impact loads. Static and dynamic vehicle impact simulations were carried out on the basis of AASHTO LRFD design specifications. In case of the static analysis, equivalent static loads specified in the AASHTO codes are loaded on the edge beams and in case of the dynamic analysis, FEM vehicle models are modeled by applying the dynamic test specifications of AASHTO codes. As a result, it is shown that U-channel bridge system has sufficient safety against static and dynamic impact loads specified in the AASHTO LRFD design specifications.

Secondary Buckling Behaviour of Plate under Inpane Compressive Loading (면내압축하중(面內壓縮荷重)을 받는 판(板)의 2차좌굴거동(次座屈擧動)에 관한 연구(硏究))

  • J.Y. Ko;T. Yao;J.K. Paik
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.3
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    • pp.66-80
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    • 1996
  • Recently, HT steel has been widely used in structure, and this enables to reduce the plate thickness. To use the HT steel effectively for a ship hull, the plate thickness becomes thin so that plate buckling may take place. Therefore, precise assessment of the behaviour of plat above primary buckling load is important. The plate under the load, that is called, secondary buckling load may undergo abrupt changes in wave form after primary buckling. This is very important when the collapse strength of the whole structures is considered. From this point of view, this paper discusses secondary buckling behaviour of thin plate under inplane compressive loading. A elastic large deflection analysis of plates with initial imperfection is performed assuming uniaxial compression, respectively, and the influence of secondary buckling is investigated. It is known that square plate is not influenced by non-symmetrical deflection coefficient but influenced by symmetrical deflection coefficient. Also, it has been found that rectangular plate($\alpha$=a/b) is influenced by all deflection coefficient, and the reduction of inplane stiffness of the plate after primary buckling is continued.

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A case study of 3D seismic reflection imaging in an area of ground subsidence (지반 침하지역에서의 3차원 탄성파 반사법에 의한 지하구조 영상화 사례)

  • Ko, Kwang-Beom;Lee, Doo-Sung
    • 한국지구물리탐사학회:학술대회논문집
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    • 2000.09a
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    • pp.158-172
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    • 2000
  • In order to visualize mine cavities, 3D seismic reflection data were acquired at the ground subsidence sites near Nampung coal mine area, Neukguri, Dogye, Samchuck. Full range 3D array with complete range of azimuths on the bins was considered in the data acquisition design. Because of poor S/N data, we estimated the stacking velocities by CVS method, and we estimated the shot and receiver statics on the shot and receiver stack data. We could confirm that features of ground collapse that were expected from the subsidence. In order to visualize the cavities, we need to apply more sophisticated processing schemes, such as velocity analysis, residual statics correction.

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Development of PBD Method for Concrete Mix Proportion Design Using Bayesian Probabilistic Method (Bayesian 통계법을 활용한 성능기반형 콘크리트 배합설계방법 개발)

  • Kim, Jang-Ho Jay;Phan, Duc-Hung;Lee, Keun-Sung;Yi, Na-Hyun;Kim, Sung-Bae
    • Journal of the Korea Concrete Institute
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    • v.22 no.2
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    • pp.171-177
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    • 2010
  • Recently, Performance Based Design (PBD) method has been studied as a next generation structural design method, which enables a designed structure to satisfy the required performance during its service life. One method of deciding whether the required performance has been satisfied is Bayesian method, which has been commonly used in seismic analysis. Generally, it is presented as a conditional probability of exceeding some limit state (i.e., collapse) for a given ground motion. In PBD of concrete mixture design, the same methodology can be applied to assess concrete material performance based on some conditional parameters (i.e. strength, workability, carbonation, etc). In this paper, a detailed explanation of the procedure of drawing satisfaction curve by using Bayesian method based on various material parameters is shown. Also, a discussion of using the developed satisfaction curves for PBD for concrete mixture design is presented.

Application of Ubiquitous Sensor Network at Construction Sites (건설 시공현장에서의 USN 활용)

  • Moon, Sung-Woo;Choi, Byoung-Young;Ji, Young-Eun;Seo, Ki-Jeong
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.905-908
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    • 2007
  • Concrete placement work is executed using temporary structures such as formwork, support, etc. The temporary structures could collapse when they are not properly supported, and need to be monitored for structural safety. This paper introduces a USN (Ubiquitous Sensor Network)-based monitoring system that are being tested at the Pusan National University for increasing structural safety. The system takes advantage of ubiquitous technologies together with a variety of sensors, which allows for wireless transmission of construction monitoring data. The temporary structures are constantly monitored to find out whether the structures are being supported in a stable condition. A field test is being conducted to acquire data, and use them for evaluating the safety condition of the construction operation.

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