• Korean Journal of Construction Engineering and Management
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• v.25 no.1
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• pp.13-22
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• 2024

On January 8, 2021, the Act on the Punishment of Severe Disasters passed the Legislation and Judiciary Committee and has been in effect in earnest since January 2022. However, safety accidents at construction sites are still continuing, and it is necessary to discuss ways to improve the safety awareness of construction workers. Therefore, in this study, data were collected through a survey of construction site workers, and the effect of the organizational climate of the workplace on the level of safety consciousness of workers was studied. As a result of the study, the factors of organizational structure, guaranteeing autonomy and consideration of supervisors among the organizational climate of the workplace had a positive effect on the improvement of workers' safety awareness. Based on this, this researcher suggested that workers should be delegated the authority to perform some tasks according to the situation and content of the work during the field work and that incentives should be compensated according to performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1375-1380
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• 2021

Korea's security response to application service app is still insufficient due to the initial opening of the public safety network. Therefore, preemptive security measures are essential. In this study, we proposed to establish a 'public safety network app security system' to prevent potential vulnerabilities to the app store that distributes app in public safety network and android operating system that operate app on dedicated terminal devices. In order for an application service app to be listed on the public safety network mobile app store, a dataset of malicious and normal app is first established to extract characteristics and select the most effective AI model to perform static and dynamic analysis. According to the analysis results, 'Safety App Certificate' is certified for non-malicious app to secure reliability for listed apps. Ultimately, it minimizes the security blind spots of public safety network app. In addition, the safety of the network can be secured by supporting public safety application service of certified apps.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.277-280
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• 2004

최근 디지털 가전과 모바일 컴퓨팅이 화두로 떠오르면서 내장형 기술이 전성기를 맞이하고 있으며, 다양한 내장형 시스템들간의 상호 운용성, 플랫폼 독립성과 이식성을 지원할 수 있는 환경을 제공하는 내장형 미들웨어의 중요성이 부각되고 있다. 미들웨어는 신뢰성, 안전성, 보안성, 실시간성 등과 같은 기능에 직접 포함되지 않는 비기능적 요구를 응용 분야에 따라 요구할 수 있으며, 그 때마다 다양한 비기능적 요구에 맞는 미들웨어를 각기 따로 개발하는 것은 지극히 어려운 일이다. 따라서, 비기능적 요구에 적합하게 미들웨어를 동적으로 재구성하는 컴포넌트 개발 방법이 주목 받고 있으며, 이를 통해 재구성된 내장형 미들웨어에서는 비기능적 요구인 실시간성이 요구되므로, deadline 만족 여부를 확인하는 스케쥴링 분석이 중요하다. 많은 최적의 스케쥴링 분석 알고리즘이 존재하나 그들 중 어느 것도 동적 재구성이 될 때 태스크 집합상의 가정(assumption)이 변경되는 내장형 미들웨어를 만족 시킬 수 없다. 가정에 적합한 스케쥴링 알고리즘으로 대체하기 위한 제안들은 대부분 정적 조립 환경에서 새로운 버전에 의해 기존 클래스를 교체하는 코드 수정에 기반하나, 동적 재구성을 통해 행위를 변경하는 내장형 미들웨어에서는 응용하기 어렵다. 따라서, 본 논문에서는 동적 재구성 환경에서 수행되는 내장형 미들웨어를 위해, 적합한 스케쥴링 알고리즘으로 대체 할 수 있는 스케쥴러를 런타임 컴포넌트 개조 기술 중 하나인 Type-safe delegation이 적용된 strategy 패턴을 기반으로 설계하였으며, 이를 통해 내장형 미들웨어 스케쥴러의 유연성과 확장성을 증가하는 방안을 제시하였다.

• Journal of the Korean Geotechnical Society
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• v.33 no.7
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• pp.29-41
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• 2017

There are uncertainties about the seismic load caused by seismic waves, which cannot be predicted due to the characteristics of the earthquake occurrence. Therefore, it is necessary to consider these uncertainties by probabilistic analysis. In this paper, procedures to develop a fragility curve that is a representative method to evaluate the safety of a structure by stochastic analysis were proposed for cut slopes. Fragility curve that considers uncertainties of soil shear strength parameters was prepared by Monte Carlo Simulation using pseudo static analysis. The fragility curve considering the uncertainty of the input ground motion was developed by performing time-history seismic analysis using selected 30 real ground input motions and the Newmark type displacement evaluation analysis. Fragility curves are represented as the cumulative probability distribution function with lognormal distribution by using the maximum likelihood estimation method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.97-105
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• 2009

This study was conducted for the purpose of examinating the safety and economical efficiency of large high tension bolted joints. The specimen using F10T-M30 large high strength bolts has been selected and static tensile test has been conducted to evaluate the slip characteristics. In addition, finite element analysis has been carried out to estimate the number of required bolts. As a result, the average slip coefficient of M30 high strength bolts exceeded 0.4 - the standard in highway bridge design specification - and has satisfied the slip strength, which is the same as that of M22 high strength bolts. In addition, if F13T-M22 high strength bolts were applied, the number of required bolts decreased by 21%, and if F10T-M30 high strength bolts were applied, the number of required bolts decreased by 46%, that leads to the conclusion that the economical efficiency in accordance with diametering of high strength bolts was now verified.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.495-501
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• 2019

Recently, research has been carried out into the use of carbon fiber reinforced polymer (CFRP), which has good tensile strength and corrosion resistance, as an alternative to rebar. But as of yet, the research into fatigue failure of CFRP is insufficient. In this paper, an analysis was performed of the mechanical behavior and failure patterns of CFRP reinforced concrete beams according to static and cyclic loads, in order to evaluate the safety and validity of CFRP rebar as an alternative material for rebar. The cyclic load ranged from 10 % to 70% of the ultimate load, and was loaded at a speed of 3Hz using a sine wave in the form of a three-point loading method. Through the static load test, the maximum load or stiffness of the beam was found to increase remarkably with the increase of the reinforcement, but the fatigue test showed that the number of repetitions decreased and the amount of deflection increased with the increase of the reinforcement.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.11-22
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• 1999

In this study, the validity of the currently used seismic regulations for seismic isolated building structures is investigated, and a new formula for vertical distribution of seismic load is proposed. The distribution formula in UBC-91 did not provide sufficient safety, and thus revised in 1994. However it is pointed out that the revised formula overestimates the seismic load because of its similarity to that of the fixed-base structure. Therefore, in the proposed approach, it is intended to satisfy safety, economy, and applicability by combining the mode shapes of the seismic isolated structure idealized as two degrees of freedom system and those of fixed-base structure. For verification of the proposed formula, both a moment resisting frame and a shear wall system are analyzed. The results obtained from the proposed method turn out to be close to the results from a dynamic analysis.

• Journal of Korean Home Economics Education Association
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• v.21 no.3
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• pp.111-122
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• 2009

This study assessed the levels of knowledge and behavior about food safety, the factors influencing them and the causal relationship between them. The data were collected from 297 high school students in Gyeongbuk region by the self-administered questionnaire. The questionnaire was composed of closed-end questions regarding each respondent's characteristics such as sex and grade, recognition on food safety, concern about hazardous elements towards foods and knowledge and behavior about food safety. The results of this study were as follows. Both levels of knowledge and behavior about food safety were not particularly high. The factors affecting the level of knowledge about food safety were mother's age and concern about hazardous elements towards foods. Grade, father's educational level, concern about hazardous elements towards foods, and the level of knowledge about food safety influenced the level of behavior about food safety. The results of the path analysis showed that grade and father's educational level directly affected the level of behavior about food safety. In addition, concern about hazardous elements towards foods had direct and indirect effect on the level of behavior about food safety On the other hand, the level of knowledge about food safety had an direct influence on the level of behavior about food safety.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1222-1230
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• 2022

The rotor blade is an important component of a tidal stream turbine and is affected by a large thrust force and load due to the high density of seawater. Therefore, the performance must be secured through the geometrical and structural design of the blade and the blade structural safety to which the composite material is applied. In this study, a 1 MW class large turbine blade was designed using the blade element momentum (BEM) theory. GFRP is a fiber-reinforced plastic used for turbine blade materials. A sandwich structure was applied with CFRP to lay-up the blade cross-section. In addition, to evaluate structural safety according to flow variations, static load analysis within the linear elasticity range was performed using the fluid-structure interactive (FSI) method. Structural safety was evaluated by analyzing tip deflection, strain, and failure index of the blade due to bending moment. As a result, Model-B was able to reduce blade tip deflection and weight. In addition, safety could be secured by indicating that the failure index, inverse reserve factor (IRF), was 1 or less in all load ranges excluding 3.0*Vr of Model-A. In the future, structural safety will be evaluated by applying various failure theories and redesigning the laminated pattern as well as the change of blade material.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.313-320
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• 2012

A hybrid floating structure system combined with pontoon and semi-submersible type modules is proposed. This new system can reduce tensile forces of bottom slabs which could cause fatal damage of concrete floating structures. We performed a parametric study on the dimensions of this new system and investigate the sensitivity of the parameters to the behavior. In order to investigate various cases efficiently, we developed a simple two-step static analysis method for the fluid-structure interaction. An optimum system is derived from the investigation of the analysis results, weights and drafts of the hybrid structure. This study shows that introducing this new system to concrete floating structures is an effective way to reduce the tensile force of the bottm slab of such a floating structure. Also, it was found that when the length of the semi-submersible module is about 15%, the behavior would be optimal in the considered case.