• 한국ITS학회 논문지
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• 제13권3호
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• pp.107-114
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• 2014

본 연구에서는 고령자와 비고령자의 성격과 교통안전 연관성을 분석하기 위한 목적으로 요인분석을 통해 고령자와 비고령자의 다양한 성격의 잠재요인을 도출하고 이를 요인회귀모형을 적용하여 성격과 교통안전의 연관모델을 구축하였다. 분석결과, 비고령자는 긍정적이고 활발하며 업무에 대한 자각이 높고 타인에 대한 배려가 부족할수록 교통여건의 만족도뿐만 아니라 과속경향이 높고 교통사고에 노출될 가능성이 높은 것으로 나타났다. 한편, 고령자는 업무성취에 대한 자각(완벽성, 효율성)이 높을수록 다시 말해 상대적으로 고등교육을 받은 고령자일수록 교통여건에 대한 만족도와 과속경향이 감소되며 사회활동이 많아질수록 교통사고에 노출되는 가능성이 높아지는 것으로 나타났다. 본 연구결과는 교통안전을 증진시키기 위한 도로이용자 맞춤형 교통안전 교육 및 정책 개발의 기초자료로 활용될 수 있을 것으로 판단된다.

• 한국건설관리학회논문집
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• 제19권5호
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• pp.101-110
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• 2018

건설업의 안전사고는 과거부터 현재까지 지속적인 증가추이를 보이고 있다. 이러한 건설현장의 안전사고를 미연에 방지하거나 최소화하기 위해서는 현장관리자 및 근로자들의 적극적이고 체계적인 안전관리 활동이 필요하다. 그러나 기존 선행연구들에서는 현재 건설현장의 규모별 안전 조직체계가 어떻게 구성되어 있고, 이들의 안전지식 및 업무수행 수준이 어느 정도인지를 명확히 파악한 연구가 미흡하다. 특히, 이들의 안전지식 공유 및 안전업무 협력체계가 어떠한 형태로 이루어지고 있는지를 분석하고, 이를 시각적으로 표현한 연구는 부재한 실정이다. 이에 본 연구는 국내 건설현장의 일반화된 안전 조직체계를 현장규모별로 도출하고, SNA 기법을 통해 구성원들의 안전지식 및 협력체계를 분석하여 향후 건설현장의 효율적인 안전관리 체계구축을 위한 실무 자료를 제시함을 목적으로 수행되었다.

• Journal of Power Electronics
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• 제7권1호
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• pp.64-71
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• 2007

This paper proposes a novel active frequency drift (AFD) method to improve the islanding detection performance with minimum current harmonics. To detect the islanding phenomenon of grid-connected photovoltaic (PV) inverters concerning the safety hazards and possible damage to other electric equipment, anti-islanding methods have been described. The AFD method that uses chopping fraction (cf) enables the islanding detection to drift up (or down) the frequency of the voltage during the islanding situation. However, the performance of the conventional AFD method is inefficient and causes difficulty in designing the appropriate cf value to meet the limit of harmonics. In this paper, the periodic chopping fraction based on a novel AFD method is proposed. This proposed method shows the analytical design value of cf to meet the test procedure of IEEE Std. 929-2000 with power quality and islanding detection time. To verify the validation of the proposed method, the islanding test results are presented. It is confirmed that the proposed method has not only less harmonic distortion but also better performance of islanding detection compared with the conventional AFD method.

• Structural Engineering and Mechanics
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• 제39권1호
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• pp.147-168
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• 2011

To ensure safety and long term performance, structural control has rapidly matured over the past decade into a viable means of limiting structural responses to strong winds and earthquakes. Nonlinear response history analysis requires rigorous procedure to compute seismic demands. Therefore the simplified nonlinear analysis procedures are useful to determine performance of the structure. In this investigation, application of improved capacity demand diagram method in the control of structural system is presented for the first time. Developed pole assignment method (DPAM) in structural systems control is introduced. Genetic algorithm (GA) is employed as an optimization tool for minimizing a target function that defines values of coefficient matrices providing the placement of actuators and optimal control forces. The ground acceleration is modified under induced control forces. Due to this, performance of structure based on improved nonlinear demand diagram is selected to threshold of nonlinear behavior of structure. With small energy consumption characteristics, semi-active devices are especially attractive solutions for limiting earthquake effects. To illustrate the efficiency of DPAM, a 30-story steel moment frame structure employing the semi-active control devices is applied. In comparison to the widely used linear quadratic regulation (LQR), the DPAM controller was shown to be just as effective and better in the reduction of structural responses during large earthquakes.

• 한국유체기계학회 논문집
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• 제17권6호
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• pp.84-88
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• 2014

A long term passive cooling system is considered as the most important safety feature for the nuclear design after the Fukushima Daiichi nuclear power plant accident in 2011. The conventional active pump driven safety systems are not available during a station Black Out (SBO) accident. The current design requirement on cooling time of the Passive Auxiliarly Feedwater System (PAFS) is about 8 hours only. To meet the 72 hours cooling time, the pool capacity of cooling water tank should be increased as much as 3~4 times larger than that of current water cooling tank. In order to extend the cooling time for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility of the combined passive air-water cooling system. The current pool capacity of water cooling system is preserved, and the cooling capability is extended by an additional air cooler.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.146-157
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• 1999

Safety systems for road vehicles have been rapidly developed in recent years. Especially, the VDC(Vehicle dynamics Control) system is a new active safety system for road vehicles which controls its dynamic vehicle motion in emergency situations . In the case of configuring the VDC system by utilizing the ABS(Anti-lock Brake System), the role of a control logic which directly influences the vehicle motion is very important. In this study the performance of the VDC vehicle was compared to the performances of the CBS (Conventional Brake system )and ABS vehicle. For various driving conditions , the simulation of vehicle dynamics with known VDC control logics was performed. Analysis results showed the VDC vehicle could stably perform even on the road of low coefficient of friction. In addition it was shown that the basic control logic for the VDC system could outstandingly improve driving stability in the case of braking as well as constant speed cruising.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.222-227
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• 1998

Collision warning systems have been an active research and development area as the interests and demands for ASV's (Advanced Safety Vehicles) have increased. This paper presents an experimental investigation of a collision warning system for automobiles. A collision warning HiLS(Hardware-in-the-Loop Simulation) system has been designed and used to test the collision warning algorithm, radar sensors, and warning displays under realistic operating conditions in the laboratory. the collision warning algorithm is operated by a warning index, which is a function of the warning distance and the braking distance. The computer calculates velocities of the preceding vehicle and following vehicle, relative distance and relative velocity of the vehicles using vehicle simulation models. The relative distance and the relative velocity are applied to the vehicle simulator controlled by a DC motor.

• Smart Structures and Systems
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• 제20권6호
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• pp.759-767
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• 2017

Wear and aging associated damage is a severe problem for safety and maintenance of engineering structures. To acquire structural operational state and provide warning about different types of damage, research on damage identification has gained increasing popularity in recent years. Among various damage identification methods, the Lamb wave-based methods have shown promising suitability and potential for damage identification of plate-type structures. In this paper, a comprehensive study was presented to elaborate four remarkable aspects regarding the Lamb wave-based damage identification method for plate-type structures, including wave velocity, signal denoising, image reconstruction, and sensor layout. Conclusions and path forward were summarized and classified serving as a starting point for research and application in this area.

• 한국안전학회지
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• 제18권2호
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• pp.56-63
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• 2003

Flame retardancy and mechanical properties of recycled polyolefinic plastics/inorganic filler composite systems were investigated by using several inorganic flame retardants such as magnesium hydroxide and slag powder generated electro arc furnace Compatibilizer user each maleic anhydride functionalized polyethylene (PE-g-MAH) and polypropylene(PP-g-MAH) or used mixture of these. The effect of polymeric compatibilizers on the properties of composites was studied by tensile and impact test, differential scanning calorimetry, in the changed fracture mechanism. The improved adhesion was particularly reflected in the mechanical properties. The flame retardancy of composites was examined by measuring limiting oxygen index(LOI, ASTM D2863), smoke density(ASTM D2843) and vertical burning test(UL94). Regarding the flame retardant effect, the EAF slag powder is behaving as synergists as they are only active in the presence of magnesium hydroxide.

• 대한안전경영과학회지
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• 제14권4호
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• pp.211-218
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• 2012

In this paper, we propose a system architecture of the AMI to be applied in the modern agricultural sector. Agricultural electricity costs in South Korea is very inexpensive compared with other industries. It is expected to increase oil prices to rise over the medium to long term so the facilities must to be installed for farmers in terms of energy savings and energy costs. The research and development of plant factory which can replace the ills of modern agriculture is very active. The technologies of smart grid and plat factory are good paradigm of next generation agricultural sector. Good use of smart grid technologies, the traditional energy consumption industries, agriculture sector can be self-sufficiency industry. In this article the AMI architecture is developed and it will be applicable for modern farmers plant factory.