• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.341-358
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• 1998

The X-ray astronomy team of the Korea Astronomy Observatory(KAO) is planning to develop a multi-cell proportional counter, adopting an anti-coincidence method to reduce its internal background. We have developed a Monte Carlo code to determine the X-ray detection efficiency of the counter. As a check of our code, we successfully reproduced the detection efficiency of Ginga/LAC. In this paper, we report the simulation results for the counter being considered in KAO.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.205-211
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• 2014

The design parameters to affect the cooling capacity of a cryocooler were examined with the application of numerical modeling to optimize an inertance pulse tube cryocooler. This modeling includes the regenerator, pulse tube, inertance tube, gas reservoir, and heat exchangers. One-dimensional modeling on strings of acoustic and thermoacoustic elements was applied to compare the design parameters. The diameter and length of the pulse tube can significantly affect the cooling capacity and efficiency. The aftercooler was optimized by maintaining a certain size. The efficiency also improved as the length of inertance tube and volume of gas reservoir are increased. It was confirmed that effective design parameters are critical to the performance of an inertance pulse tube cryocooler considering the comparison of the dimensions of each part to optimize its cooling power and efficiency.

• Journal of Astronomy and Space Sciences
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• v.10 no.1
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• pp.94-102
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• 1993

We have develped a four-channel photoelectric photometer for the 61cm telescope of Sobaeksan Astronomy Observatory using optical fiber. We observed a standard star with each channel to check the efficiency difference between the channels, and found no differences. To calibrate the observing accuracy and efficiency, we have observed a short period W UMa type eclipsing binary star, BV Dra. Test observations show that the photometer is very stabel and the accuracy of the data is also increased. The observing efficiency is very increased compared with that of single channel photometer ; at least five times faster than older one in the case of one filter observation.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.258-269
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• 2022

In these days, innovative functions are required to unmanned parcel delivery lockers. As non-face-to-face transactions become the center due to the recent COVID-19 pandemic, many problem occurs in society such as theft crimes and lack of loading space. Therefore, New concept storage device is developed in korea. It has the functions that minimizes empty spaces by using the internal transport device to enable efficient space loading and refrigerate goods such as foods. In order to systematically approach the system design of the unmanned parcel delivery lockers which is the new function is applied, We applied model-based system engineering to improve the development efficiency and use a system modeling language to express the system. We conducted interworking research of CAD data including system modeling and design data. it is expected that this method will increase the effective development efficiency such as maintenance traceability and reduction of development period and cost.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.23-34
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• 2018

Recently, mainly in downtown, there have been frequent safety incidents in underground space like ground subsidence and land sinking. Out of diverse coping measures, the government is carrying forward the establishment of underground space integrated map. As a core element of the underground space integrated map, the 3D geotechnical information is used as major data of underground space impact assessment obliged in accordance with the "Special Act on the Safety Control of Underground Space Safety". The construction method of 3D geotechnical information is drawn when establishing the basic establishment plan of underground space integrated map, and the continuous construction is performed by the Integrated DB Center of National Geotechnical Information. However, it is necessary to draw concrete measures with accuracy, efficiency, and utilization. This study drew the construction plan considering the accuracy, utilization, and efficiency of 3D geotechnical information for the support of underground space safety. For this, accuracy between elevation and underground level is compared using MVS and MakeJiban which are software to construct boring information with geotechnical information in geotechnical information portal system. In the results of general analysis, the milepost-based construction of whole strata in a lump would be the most suitable in the aspect of accuracy, utilization, and efficiency. Based on the results of this study, Plan to construct 3D geotechnical information will be pursued.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.29.1-29.1
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• 2008

The temperature control system which is using liquid and gaseous nitrogen has been known as the most economical system to simulate space temperature condition due to relatively not expansive price of the liquid nitrogen (less than 0.2 USD per liter). And, among these systems, the closed loop system which circulates compressed nitrogen gas come from sprayed liquid nitrogen by blower and makes a target temperature with heat from an electrical heater and flow rate of liquid nitrogen is prevail all over the world. But, this complete closed loop system requires expansive equipments such as blower, heater, and liquid nitrogen injector, and special maintenance on the system. Therefore, KARI is developing efficient and simple open loop system which utilizes liquid and gaseous nitrogen with eliminating a special blower and other expansive units. In this study, this open loop system with more efficiency and flexibility will be designed and introduced.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3253-3269
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• 1994

In this paper a new concept, named the Extended Operational Space Formulation, has been proposed for the effective analysis and real-time control of the robot manipulators with kinematic redundancy. The extended operational space consists of operational space and optimal null space. The operational space is used to describe robot end-effector motion; whereas the optimal null space, defined as the target space of the self motion manifold, is used to express the self motion for the secondary tasks. Based upon the proposed formulation, the kinematics, statics, and dynamics of redundant robots have been analyzed, and an efficient control algorithm has been proposed. Using this algorithm, one can optimize a performance measure while tracking a desired end-effector trajectory with a better computational efficiency than the conventional methods. The effective ness of the proposed method has been demonstrated with simulations.

• Korean Institute of Interior Design Journal
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• no.29
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• pp.94-102
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• 2001

The urban land is incapacitated to grow and correspond to demand the space in urban area. And recently, rapid increasing of population and complex of urban function on pushed to develop the underground space. In Korea, the underground space development in inefficient in aspect. because development of underground space have not consistent and systematic planning method in underground environment inclounding interion design, extererior design. Therefore this study is suggested the design element for comfortable underground living environment and assortment on utilization of underground space. The results of this study on utilization are security of space through land use efficiency, conservation of historical place, building and natural environment, and technological characteristics, mental image. Accordingly, this study is proposed design element that make comfortable underground space as aspect from stimulation and diversity, sapciousness and feeling of warmth and dryness to compensate improper image of underground space, spacial orientation and way finding.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.2
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• pp.25-35
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• 2002

This paper is to evaluate an open space on university campuses enclosed within buildings, with respect to building elevation a wall of an open space including outer wall materials and window forms and an open space itself. It uses case study methods to periodically know specific details about open spaces and surrounding buildings elevation. It was found, at first, that it was emphasized vertical elements on window frames as well as building elements in an era of the 1910's to the 1930's. It, however, was changed into emphasizing on horizontal features in the era of the 1960's to the 1970's. Meanwhile the period from the 1940's to the 1950's was a turning point. The horizontal style was continued until the 1980s and the style was changed into various style mixed with various types. Secondly, an open space was recognized as a valuable design criteria for a construction of buildings in the 1930s to the 1970s. It was, however, a forgotten criteria during the late 1970's and the 1980's because of short age of the construction budget of the government. In the 1990's, the importance of open space design reappeared on the design of a block plan. Thirdly, a design style of an open space was authoritarianism using symmetrical and magnificent style in the 1910's to the 1930's. The time of 1945 to the 1950's was a turning point from authoritarianism to an idea of efficiency. In the 1960's and the 1970s, an idea of efficiency emphasizing their functions was prevalent to the design of buildings and open spaces and this trend was continued until the 1980's. A romanticism was realized on the design of an open space and surrounded building's.

• Tunnel and Underground Space
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• v.2 no.1
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• pp.1-10
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• 1992

As our global population grows each day, it is apparent that we must find new ways to provide space for habitation and the services necessary to support large urban areas. It is no longer advisable nor acceptable to continue to expand our cities on the surface, encroaching on valuable agricultural land and open space. We must also find ways to be more energy efficient in every aspect of our societies. Effective use of underground space can provide the space necessary to accommodate larger populations and the services necessary for their support in existing urban areas we can also find new ways to utilize underground facilities to improve urban efficiency and function. Underground technology has improved dramatically in the last two decades and continues to evolve to meet a great variety of applications. The confluence of available technology, economic feasibility, and greater acceptance of underground solutions with recognition of the need to change the ways we build and use out urban areas and their surrounding environment indicates that we are witnessing only the beginning of appropriate and innovative use of underground space future generations will indeed 'Think deep'.