• Computers and Concrete
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• 제32권1호
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• pp.99-117
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• 2023

The crack under the influence of the higher intensities of the stresses grows and the structure gets collapsed with the time when the crack length reaches to critical value. Therefore, the fracture behavior of a structure in terms of stress intensity factors (SIF) becomes important to determine the remaining fracture strength and capacity of material and structure for avoiding catastrophic failure, increasing safety and further improvement in the design. The robustness of the method has been demonstrated by comparing the numerical results with analytical and experimental results of some problems. XFEM is used to model cracks and holes in structures and predict their strength and reliability under service conditions. Further, XFEM is extended with a stochastic method for predicting the sensitivity in terms of output COVs and fracture strength in terms of mean values of stress intensity factors (SIFs) of a structure with discontinuities (cracks and holes) under tensile loading condition with input individual and combined randomness in different system parameters. In stochastic technique, the second order perturbation technique (SOPT) has been used for the predicting the fracture behavior of the structures. The stochastic/perturbation technique is also known as Taylor series expansion method and it provides the reliable results if the input randomness is less than twenty percentage. From the present numerical analysis it is observed that, the crack tip near to the hole is under the influence of the stress concentration and the variational effect of the input random parameters on the crack tip in terms of the SIFs are lesser so the COVs are the less sensitive. The COVs of mixed mode SIFs are the most sensitive for the crack angles (α=45° to 90°) for all the values of c₁ and d₁. The plate with the shorter distance between hole and crack is the most sensitive with all the crack angles but the crack tip which is much nearer to the hole has the highest sensitivity.

• Structural Engineering and Mechanics
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• 제48권5호
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• pp.615-642
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• 2013

In this paper a study on prestressed concrete slab bridges is presented. A design philosophy based on the concept of load balancing through prestressing is proposed in order to minimize the effects of delayed deformations due to creep. Aspects related to the stress redistribution inside these bridges for time-dependent phenomena are analyzed and discussed, by applying the principles of aging linear visco-elasticity. Prestressing is seen as an equivalent external load which counterbalances the permanent loads applied to the bridge, nullifying the elastic deflections due to sustained loads, and thus avoiding the related delayed deformations. An optimization of the structural behavior through the use of one-way prestressing is achieved. The determination of a convenient variable depth of slab bridges and the correspondent layout of tendons is considered as a useful means for applying the load balancing concept in actual cases of structures like long cantilevers or bridge decks. A case-study related to the slab bridges built 30 years ago at Jeddah in Saudi Arabia is presented and discussed, in order to show the effectiveness of the proposed approach to the conceptual design of prestressed concrete bridges.

• 한국생활과학회지
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• 제18권5호
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• pp.1047-1062
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• 2009

Nowadays, ethical consumers are increasing and they consider social values such as worker's human rights, environment and animal's welfare as key criteria in purchasing products. This study focused on the academic and practical research of ethical consumption, in which the needs and interests are now growing globally. This study addressed the concept, trend and practices of ethical consumption as well as seeking methods to support and promote ethical consumption. It examined the concept and types of ethical consumption from the perspective of the philosophy on ethical consumption. Ethical consumption was defined as a behavior that intended to improve the environment and the welfare of people and animals by purchasing products produced according to sound ethical principles and avoiding products that are made through the exploitation or the damage of people, animals and the environment. It also dealt with the practices of ethical consumption such as the fair trade movement, Clean Clothes Campaign, boycott, local food movement, animal's welfare movement. In conclusion, I suggested that consumers, companies, governments, and NGOs should make an effort to promote ethical consumption.

• 대한안전경영과학회지
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• 제20권2호
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• pp.1-8
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• 2018

This study aims to provide a real-time information to the driver by effectively operating the advanced safety device attached to the freight vehicle, thereby minimizing insecure behavior of the driver such as speeding, rapid acceleration, sudden braking, And improve driving habits to prevent accidents and save energy. Advanced safety equipment is a device that warns the driver that the vehicle leaves the driving lane regardless of the intention of the driver and reduces the risk of traffic accidents by mitigating or avoiding collision by detecting a frontal collision during driving.The main contents of this report are as follows: In case of installing a warning device on a lane departing vehicle (excluding a light vehicle) and a lorry or special vehicle with a total weight exceeding 3.5 tonnes, the driver must continue to operate unless the driver releases the function.In addition, when the automatic emergency braking system is installed, the structure should be such that the braking device is operated automatically after warning the driver when the risk of collision with the running or stopped vehicle in the same direction is detected in front of the driving lane.

• 대한간호학회지
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• 제44권5호
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• pp.525-533
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• 2014

Purpose: This study was done to propose and test a predictive model that would explain and predict fall prevention behaviors in postmenopausal women. The health belief model was the theoretical basis to aid development of a nursing intervention fall prevention program. Methods: Data for 421 postmenopausal women were selected from an original data set using a survey design. The structural equation model was tested for 3 constructs: modifying factors, expectation factors, and threat factors. Expectation factors were measured as relative perceived benefit (perceived benefit minus perceived barrier), self-efficacy, and health motivation; threat factors, as perceived susceptibility (fear of falling) and perceived severity (avoiding activity for fear of falling); and modifying factors: level of education and knowledge about fall prevention. Data were analyzed using SPSS Windows and AMOS program. Results: Mean age was 55.7 years (range 45-64), and 19.7% had experienced a fall within the past year. Fall prevention behaviors were explained by expectation and threat factors indicating significant direct effects. Mediating effect of health beliefs was significant in the relationship between modifying factors and fall prevention behaviors. The proposed model explained 33% of the variance. Conclusion: Results indicate that fall prevention education should include knowledge, expectation, and threat factors based on health belief model.

• 여성건강간호학회지
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• 제18권4호
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• pp.257-267
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• 2012

Purpose: This study was conducted to identify the caring experience of the mothers of childhood burn patients. Methods: Data were collected from 28 mothers of childhood burn patients, through semi-structured in-depth interviews. Data were categorized and coded by using content analysis. Results: 27 categories and 102 statements were drawn from 4 domains. The analyzed domains were psychological sufferings, confronted harsh reality, coping method, and future concerns. Psychological sufferings were categorized heartache, sense of guilt, confusion, regret, depression, sorriness, getting hurt, frustration and upset feeling. Confronted harsh nature were categorized economic difficulty, physical burn-out, lack of caring other children and family troubles. Coping method were categorized positive thinking, having hope, ventilating feelings, accepting the situations, demanding help from family members, changing patterns of the burned child rearing, collecting information for burn treatment, refusing accept the condition of burned child, avoiding personal and social relationship, and reliance on religion. Concerns were categorized concerns of growth and adaptation of the burned child, anxiety for scar, concerns of adapting school life and vague future concerns. Conclusion: The nursing interventions for early assessing psychological problems and providing social supports for caring both burn patients and other siblings should be provided to the mothers of childhood burn patients.

• 한국정보시스템학회지:정보시스템연구
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• 제24권1호
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• pp.147-168
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• 2015

Why people reduce or stop using social network services(SNS), which are regarded as a mean of relationship and communication, unlike the early trend? To explain the phenomenon, this study tries to predict psychological decision making process of users from perspectives of cognitive dissonance theory. From this perspective, this study attempted an integrative approach that reflected 'User's literacy' indicating the ability of individuals to use SNS, and 'negative mass media influence' such as media reports on side effects or the bad experiences of acquaintances, along with the 3 factors used in the SNS Prior research. This study conducted an empirical analysis by surveying 256 facebook users, and the major findings are as follows:- First, Social-overload, complexity, uncertainty and negative media influence are significantly affect dissonance on the use of SNS. Second, Dissonance on the use of SNS significantly affects the behavior that possibly reduces and limits the use of SNS. In other words, the users who have experienced psychological dissonance respond passively by avoiding the use of SNS to resolve the dissonance. Third, the moderating effect of User's literacy wasn't a significant. This study presents a clue to understand psychological decision making process of use of SNS and a guideline for establishing practical strategies. In addition, it is important to note that this study contributes to expansion of theoretical discussion about usage.

• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.475-481
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• 2007

본 연구는 공공공간의 하나인 천안역을 중심으로 사인에 있어서 분포 및 종류를 분류하고 구간별로 조사 분석한 연구이며, 그 결과로 구간별 설치된 사인의 종류에 대한 문제, 사인의 설치에 있어서 위치에 대한 문제, 밀집되어 설치된 정보(사인)에 대한 문제가 나타났다. 이에 각 구간별 설치된 정보(사인)의 차이와 밀집되게 설치되어 있는 정보에서 각 장소에 고르게 분배되는 정보제공의 필요성과, 사인의 무계획적인 설치에서 이용자의 행동을 고려한 적절한 위치의 정보 설치가 요구된다. 따라서 사인의 설치에는 장소마다 보행자에게 필요한 정보의 파악이 우선되어야 하며 그 장소마다 적절한 정보의 제공으로 이용자에게 안정적인 환경 부여가 필요하다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.391-398
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• 2005

In this investigation, turbulent premixed combustion and flame front propagation in a gas turbine combustion chamber is studied. Direct numerical simulation of turbulent reacting flows demands extremely high computational resources, especially in more complicated geometry. The alternative choice may be left for Large Eddy Simulation (LES) by which only large scales are solved directly. In combustion problems, capturing the large scales' behavior without solving the details of small scales is a difficult task. Using a transport equation for description of the flame front propagation and therefore avoiding the calculation of inner flame structure is the basic idea of this study. For this purpose. the so-called G-equation has been used by which any iso-level of the G variable provides the flame location. A comparison with the experiment indicates that the present method can predict a turbulent velocity field and also capture a instantaneous 3-dimensional flame structure.

• 한국지능시스템학회논문지
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• 제20권3호
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• pp.413-421
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• 2010

본 논문에서는 로봇 축구용 카메라를 사용하는 기존 경로계획의 제한적인 사항을 극복하기 위해서 컬러 인식법에 의한 경로계획방법을 제시한다. 제안된 연구에서는 움직이는 목표물이 스웜로봇과 멀리 있어도 로봇의 직선 시야를 기반으로 동료 로봇을 따라가며, 움직이는 목표물을 추적 할 수 있다. 제안된 포텐셜 필드는 동료 로봇과의 충돌과 장애물과의 충돌을 피하면서 스웜 로봇들이 움직이는 목표물을 향하여 이동하게 한다. 결국, 스웜 로봇들 사이의 시각적 도움에 의해 최종 목표물에 모든 스웜 로봇들이 도달하게 된다. 제안된 방법은 움직이는 파티클, 즉 점 로봇이 아닌 논홀로노믹 제한이 있는 유니 사이클 로봇들을 대상으로 자기 조직화 방법을 제시하기 때문에 실제 하드웨어 적용시 유용하다.