• 한국전자거래학회지
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• 제6권1호
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• pp.17-33
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• 2001

EC(Electronic Commerce) which is done on the virtual space through Internet has strong point like independence from time and space. On the contrary, it also has weak point like security problem because anybody can access easily to the system due to open network attribute of Internet, Therefore, we need the solutions that protect the EC security problem for safe and useful EC activity. One of these solutions is the implementation of strong cipher system. YK2(Young Ku King) cipher system proposed in this paper is good solution for the EC security and it overcome the limit of current block cipher system using 128 bits key length for input, output, encryption key and 32 rounds. Moreover, it is designed for the increase of time complexity by adapting more complex design for key scheduling algorithm regarded as one of important element effected to encryption.

• 한국주거학회논문집
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• 제13권3호
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• pp.85-91
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• 2002

The purpose of this study is to find out the effective planning guidelines of elderly housing fur the aged people living with their sons or daughters. To investigate the actual conditions and the problems of housing environments, two hundred and six old people in Gwangiu city, aged over sixty and living with their sons and daughters, were interviewed individually and they provided the useful answers to the questions. The houses for three generations need to have the proper degree of privacy fur each family member, by arranging rooms for their own independent living space while securing the sufficient common space. Therefore, independent and safe living environments are to be made for the elderly and the choice of various types be made according to their own demands. It is also necessary to guarantee the continuation of inhabitation by establishing health care systems and life support services.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1693-1703
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• 2003

This paper presents a new local obstacle avoidance method for indoor mobile robots. The method uses a new directional approach called the Lane Method. The Lane Method is combined with a velocity space method i.e., the Curvature-Velocity Method to form the Lane-Curvature Method (LCM). The Lane Method divides the work area into lanes, and then chooses the best lane to follow to optimize travel along a desired goal heading. A local heading is then calculated for entering and following the best lane, and CVM uses this local heading to determine the optimal translational and rotational velocities, considering some physical limitations and environmental constraint. By combining both the directional and velocity space methods, LCM yields safe collision-free motion as well as smooth motion taking the physical limitations of the robot motion into account.

• 한국화재소방학회논문지
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• 제4권1호
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• pp.13-19
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• 1990

Recently, the expansion of underground shopping street has a tendency to make a large maze in urban underground space. As the passers -by in underground streets have little information about these spaces, there can be a great danger at fire. From this point of view, this study aims at offering the basic data which needs to make a reasonable planning of escape facilities of underground shopping street. Therefore, safe performance evaluation program is developed for evaluating inhabitants' safety at each model. This program is composed of systematic equations which generalize each phenomenon at fire.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.163-168
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• 2003

Analytical approach is applied to predict temperature of satellite box under worst hot condition from fairing jettison to separation. The box is tried to solve analytically which is exposed to known environmental heating condition and has internal heating and irradiation to space. For a single thermal mass, governing equation for temperature is simplified to 1st order ordinary differential equation(ODE) by several assumptions. Two cases are considered. The one is for constant mass box and the other is for mass-varying box. Each case has three different analytical solution by sign of constant term in ODE. One analytical solution for constant mass is applied to physical launch stage condition. It is concluded that the present analytical method can be used to quick predict the temperature of a satellite box and check whether a satellite is safe against space environment during launch stage.

• International Journal of Aeronautical and Space Sciences
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• 제1권2호
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• pp.30-42
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• 2000

On-orbit thermal environment test of KOMPSAT was performed in early 1999. An analysis of the test data are addressed in this paper. For the thermal-environmental simulation of spacecraft bus, an artificial heating through the radiator zones and onto some critical heat-dissipating electronic boxes was made by Absorbed-heat Flux Method. Test data obtained in terms of temperature history were reduced into flight heater duty cycles and converted into the total electrical power required for spacecraft thermal control. Verification result of flight heaters dedicated to the bus thermal control is presented. Additionally, an exhaustive heating-control process for maintaining the spacecraft thermally safe and for realistic simulation of the orbital-thermal environment during the test are graphically shown. Qualitative suggestions to post-test model correlation are given in consequency of the analysis.

• International Journal of Aeronautical and Space Sciences
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• 제5권2호
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• pp.43-53
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• 2004

Collision avoidance for multiple aircraft can be stated as a problem ofmaintaining safe distance between aircraft in conflict. Optimal collision avoidanceproblem seeks to minimize the given cost function while simultaneously satisfyingconstraints. The cost function could be a function of time or control input. This paper addresses the trajectory time-optimization problem for collision avoidance of unmanned aerial vehicles(UAVs). The problem is difficult to handle in general due to the two-point boundary value problem subject to dynamic environments. Some simplifying aleorithms are used for potential applications in on-line operation.Although under possibility of more complicated problems, a dynamic problem is transformed into a static one by prediction of the conflict time and some appropriate assumptions.

• 대한안전경영과학회지
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• 제6권4호
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• pp.99-106
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• 2004

In developing criteria for establishing workstation reach limits, it is essential to select the appropriate anthropometric stereotype for solving a specific design problem. The most important factor for comfortable workstation is to eliminate trunk flexion from the neutral (upright) posture. A solution to this design can be developed using population stature and link length data. This paper provides a methodology for design of comfortable workstation using anthropometric stereotype. Application of this methodology can be utilized in various designs for work space including standing and sitting workplace. For the purpose of this study, the data are measured by some parts on body such as stature, arm length, wrist height, elbow height, and shoulder hight. The samples for this study are randomly chosen from university students in Seoul and Kangnung during sixteen months (2003.3-2004.6).

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.31.1-31.1
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• 2010

On-Orbit상에서 인공위성의 탑재소프트웨어를 교정하는 경우는 크게 위성의 하드웨어 문제를 소프트웨어적으로 해결/완화, 임무 중 소프트웨어 기능 향상 그리고 지상테스트 동안 확인되지 못한 소프트웨어 문제를 수정하기 위해서 사용된다. 탑재소프트웨어 설계과정에서 이러한 요구조건을 만족할 수 있도록 탑재소프트웨어가 설계되어야 하며 소프트웨어 교정을 위한 잉여 메모리를 반드시 할당해야 한다. 또한, 탑재소프트웨어 실행파일 생성할 경우에도 각 섹션별로 패치가 가능하도록 메모리 맵을 생성해야한다. 기존 저궤도 위성에서는 휘발성 메모리인 RAM 영역에 한해서만 탑재소프트웨어 교정이 가능하였으나 현재 개발 중인 차세대 저궤도 위성에서는 비휘발성 메모리 영역 즉 SGM(Safe Guard Memory)와 NVMEM(Non-Volatile Memory)을 이용하여 탑재소프트웨어를 교정할 수 있는 방식을 제공하고 있다. 이 논문에서는 차세대 저궤도 위성의 탑재소프트웨어의 실시간 교정을 위한 탑재소프트웨어 아키텍처와 제한 사항에 대해서 설명하며 실제 탑재소프트웨어를 교정 하는 방안 과 절차에 대하여 설명한다.

• Steel and Composite Structures
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• 제30권4호
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• pp.315-325
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• 2019

Double skin composite walls offer structural and economic merits over conventional reinforced concrete counterparts in terms of higher capacity, greater stiffness, and better ductility. This paper investigated the axial behavior of double skin composite walls with steel truss connectors. Full-scaled tests were conducted on three specimens with different height-to-thickness ratios. Test results were evaluated in terms of failure mode, load-axial displacement response, buckling loading, axial stiffness, ductility, strength index, load-lateral deflection, and strain distribution. The test data were compared with AISC 360 and Eurocode 4 and it was found that both codes provided conservative predictions on the safe side.