• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.239-241
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• 2011

Recently, studies on the indoor positioning system in application of wireless AP have been actively going on. The indoor wireless positioning system can be classified into several types according to the positioning techniques. Among them, the fingerprint technique is a technique that establishes the radio map by collecting MAC information of AP and RSSI (Received Signal Strength Indication) before executing positioning and then determines the position in comparison with the information of AP collected during the course of positioning. In the traditional fingerprint techniques, they control and manage by installing APs that are utilized for positioning. However, in case of specific indoors, the management can be done by installing a small number of APs but, in case of wide outdoors, it's practically impossible to install and manage equipments for positioning. In order to solve such problem, there is an improved fingerprint technique that utilizes the APs that are already scattered around. This technique will allow positioning without additional cost, but even the improved fingerprint positioning technique may incur dropped accuracy as well due to wide fluctuation of the AP information. In this paper, the traditional fingerprint technique and the improved fingerprint technique are explained in comparison, and we will compares difference in performance with the proposed WPS_WS (Wi-Fi Positioning System_Weak Signal) technique.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.81-98
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• 1999

The influence of tunnelling on buildings has become an important issue in urban areas. The problem is an interactive one: not only do tunnelling settlements affect existing structures, but existing structures affect tunnel-induced soil movements. In order to examine the constraint of surface settlement and the degradation of building damage parameters, 3-dimensional elasto-plastic finite element analyses are peformed. Also, in this paper, the results of the parametric studies for the variations of the damage parameters due to the ground movements are presented by utilizing 2-dimensional elasto-plastic finite element models, totally 162 models. The width of a structure, its bending and axial stiffness, its position relative to the tunnel and the depth of tunnel are considered. The interaction is shown by reference to commonly-used building damage parameters, namely angular distortion, deflection ratio, maximum building settlements, maximum differential settlements and horizontal strain. By introducing relative stiffness parameters which combine the bending and axial stiffness of the structure with its width and stiffness of soil, design curves are established. These give a guide as to the likely modification of the greenfield settlement trough caused by a surface structure. They can be used to give initial estimates of likely building damage.

• KIEAE Journal
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• v.17 no.1
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• pp.63-68
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• 2017

Purpose: Various studies to solve the problem of increased energy consumption in the buildings are being carried out recently. Especially, the economic feasibility and insulation performance of the air-cap have been verified so that various studies regarding the reduction of building energy consumption have been carried out. However, previous studies regarding the air-cap were only carried out based on the verification of its insulation performance according to the size and attachment position of the air-cap. Therefore, the purpose of this study is to suggest a detachable air-cap module for improving the performance of the windows, evaluate the performance based on cooling, heating and light environments and verify its effectiveness through a real-scale testbed. Method: In this study, the energy saving performance in the circumstance where there is no attachment of an air-cap (Case 1), the circumstance where there is the attachment of air-cap on the glass surface of window (Case 2) and the circumstance where there is the attachment of an air-cap on the window frame (Case 3) were compared in order to verify the performance of the detachable air-cap module (Case 4), and the electricity consumption of cooling, heating and lighting equipment to maintain the appropriate indoor temperature and Illuminance for each case was calculated and utilized as indicators for the performance evaluation. Result: The result of this study is as follows. 1) In this study, the detachable air-cap module which was easily detachable through the principle of the magnet was suggested. 2) When Case 4 is applied, the electricity consumption of cooling and heating equipment can be reduced by 27.5%, 13.2% and 3.4% in comparison with Case 1, Case 2 and Case 3 respectively. 3) When the air-cap is applied to the window, the lighting energy consumption increases by 4 % in comparison to the non application of the air-cap, and this factor or aspect should be considered when applying the air-cap. 4) According to the performance evaluation result in consideration of cooling, heating and light environments, Case 4 demonstrates an energy saving ratio of 22.6%, 10.6% and 2.7% in comparison to Case 1, Case 2 and Case 3 respectively, indicating that it is effective for improving the performance of windows.

• The Korean Journal of Air & Space Law and Policy
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• v.9
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• pp.445-488
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• 1997

In the forthcoming 21st century new technical and scientific developments in outer space demands new approaches towards the problems arising in several fields of the use and exploitation of outer space including practical applications. The main purposes of this study are to analyze the legal problems of geostationary orbital position, telecommunication, direct television broadcasting by uses of artificial satellites. Communication via artificial Earth satellites was one of the first applications of space technology and is now one of the most developed field. From the technical and economic standpoints the advantages of world-wide satellites communication system are too all obvious. However, as the practical uses of space technology become more freguent, the legal conflicts among nations have become more divisive. One of the problem grown in uses of artificial satellites is that of the increasing shortage of suitable orbital slot positions for satellites, especially in geostationary orbit. Legal status of geostationary orbit as a limited resourece have to be reviewed in consideration of the side effect of the "First use, first-served" principle. The geostationary orbit is to be used for the benifits of all mankind and to be guaranteed for each state institutionaly in order to have eguitable access to the use of the orbit. Rapid increase of satellites broadcasting system in not only developed countries but also in developing countries opened up new possibilities with one another's scientific and cultural achievements. But there is also a potential danger that this powerful new instrument of influencing public opinion will be abused. Such a danger incudes spill-over or harmful interference. This controversial issue brings about the question whether prior consent from the receiver nation is needed to broadcast across international boundaries. Some states have rejected prior consent because it interfere with the free flow of information. Many other countries have opposed that opinion as an invasion and violation of sovereignty and as a violation of the 1967 Treaty and the UN Charter. Since declaration of the First Year of Outer Space in 1985, our country have promoted the plan of launching communication and broadcasting satellites. With the Koreasat launched in 1995 as the start, a real satellite-telecommunication era was opened in korea. According to this new development of our country, there will also rise various legal problems related to satellite broadcasting and telecommunication such as the inflow of foreign programs, the permeation of culture and the infringement of program copyright. Consequently the effective reactions to these problems in satellite-communication era should be tried including international cooperation. It is therefore to take into careful consideration the legal issues which may arise in outer space activities and to formulate positive policy on international cooperation with surrounding or advanced countries and international organization concerned. For this purpose the United Nations also prepares the UNISPACE III in 1999, to enable the international community to meet a more promising 21st century.

• Spatial Information Research
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• v.15 no.2
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• pp.111-121
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• 2007

The GPS positioning offer 3D position using code and carrier phase measurements, but the user can obtain the precise accuracy positioning using carrier phase in Real Time Kinematic(RTK). The main problem, which RTK have to overcome, is the necessary to have a reference station(RS) when using RTK should be generally no more than 10km on average, which is significantly different from DGPS, where distances to RS can exceed several hundred kilometers. The accuracy of today's RTK is limited by the distance dependent errors from orbit, ionosphere and troposphere as well as station dependent influences like multipath and antenna phase center variations. For these reasons, the author proposes Network based GPS Carrier Phase Differential Positioning using Multiple RS which is detached from user receiver about 30km. An important part of the proposed system is algorithm and software development, named DAUNet. The main process is corrections computation, corrections interpolation and searching for the integer ambiguity. Corrections computation of satellite by satellite and epoch by epoch at each reference station are calculated by a Functional model and Stochastic model based on a linear combination algorithm and corrections interpolation at user receiver are used by area correction parameters. As results, the users can obtain the cm-level positioning.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.70-81
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• 2009

Statement of problem: The position and length of cantilever influence on the stress distribution of implants, superstructure and bone. In edentulous mandible, implant-supported cantilever prostheses that based 4 or 6 implants between mental foramens has been attempted. Excessive bite force loaded at cantilever prosthesis causes bone resorption and breakage of superstructure prosthesis around posterior implants. To complement the cantilever length of conventional prosthesis, In 1992, (McCartney) introduced "cantilever-rest-implant" and Malo reported "All-on-Four" in 2003. Purpose: Analyze and compare the stress distribution of conventional cantilever prostheses with rest implant and All-on-$Four^{TM}$ implant prostheses. Material and method: The external loads(300 N vertically, 75 N horizontally) are applied to first molar area. The stress value, stress distribution and aspect of stress dispersion are analyzed by three-dimensional finite element analysis program, ANSYS ver. 10.0. Results: 1. The rest implant and "All-on-Four" implant system are superior to conventional cantilever prostheses to reduce stress on the bone and the superstructure around implants. 2. The rest implant was of the greatest advantage to stress distribution on bone, implant and superstructure. 3. With same number of implants, distally tilted implants are preferred to conventional cantilever prostheses for reducing the length of cantilever.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.183-190
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• 1993

Determining accurate geoid height is very important because it is the basis of the 3-D coordinate transformation and determination of the orthometric height. In this study, for determining the geoid height, bi-linear method grounded on the interpolation method, GPS leveling and OSU91A was applied to the $5km{\times}5km$ area and $60km{\times}60km$ area in the latitude $N\;36^{\circ}{\sim}37^{\circ}$ and the longitude $E\;127^{\circ}{\sim}128^{\circ}$. The results obtained by these methods were compared with conventional leveling data. In case of bi-linear method, it was dependent upon the shape of interpolation network and undulation of ground. If leveling data are satisfactory, GPS leveling is more proper than any other method. Also, it is 62 cm that an average difference of GPS leveling and OSU91A. As a result, in order to determine more precise geoid height, the development of local geoid model is a pressing problem to be solved. The result of the research will provide reference data for settling the 3-D coordinate transformation, and it is expected that it will also be applied to determination of 3-D position.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.421-432
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• 2010

In Korea, about 80 academic departments related to fire science are in operation throughout the country, but fire science is not included as a branch science in the science classification system acknowledged by the Ministry of Education, Science and Technology and its position as a science is not solid yet. In response to this problem, research is being made actively to establish fire science recently. This study aims at composing the fire service policy theory which is one of sub areas of fire science. First, the concept of fire service policy should be established, and fire service policies should be divided into different types. In addition, it is necessary to examine the direction of the development of fire service policies in Korea, and the unique characteristics of fire service policies should be described. Next, we will mention fire service policy making and participants, theories on the determinants of fire service policies, the execution of fire service policies, and the evaluation of fire service policies. Particularly, based on the peculiarity of fire service, it is necessary to explain policies on fire prevention and precaution, fire investigation, rescue and first aid, public campaigns for safety and prevention, fire insurance, etc. Finally, we suggest the future directions of fire service policies according to the change of environment in the future.

• Fire Science and Engineering
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• v.34 no.1
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• pp.47-54
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• 2020

This paper proposes a solution to the problems of constructing and installing sway braces for existing standpipes in narrow spaces and pits. The study develops a floor-fixed sway brace for a narrow space that can support the ground area under horizontal seismic loads (X-axis, Y-axis) as well as vertical seismic loads (Z-axis). The results of structural analysis using SolidWorks simulation showed that the eccentric load was generated in the first design according to the anchored position along the vertical direction, and the problem of exceeding the allowable stress of the material along the horizontal and vertical directions. In the second design model, deformation caused by the eccentric load along the vertical direction, similar to the first design model, did not occur. The maximum strain rate was 0.17%, which is approximately 12.84% less than the first design model (Maximum strain rate of 13.01%). It was confirmed that the structural stability and durability improved. Compressive and tensile load testing of the prototypes showed that all of them meet the performance criteria of the standard.

• Lingua Humanitatis
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• v.6
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• pp.147-166
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• 2004

Whitehead's discussion of language is not to be found in any one book or article. It is interwoven with his discussion of many other questions. He was, however, greatly concerned with the problem of symbolism in general and the uses of language. He regards language, spoken or written, as an instrument devised by men to aid them in their adjustment to the environment in which they live Language is used for many specific purposes in the process of this adjustment. Words are employed not only to refer to data and to express emotions. They may be used also to record experiences, and thoughts about these experiences. Worts also function as instruments in the organization of experiences as they are considered in retrospect. Thus words free us from the bondage of the immediate. And Whitehead's theory of meaning is implicit in his discussion of the functions of language. According to him, the human mind is functioning symbolically when some components of its experience elicit consciousness, beliefs, emotions, and usages, respecting other components of its experiences. The former set of components are the 'symbols', and the latter set constitute the 'meaning' of the symbols. Whitehead points out that one word may have several meanings, i.e. refer to several different data. In order to understand, thus, the meaning to which a word refers, it is sometimes very important to appreciate the system of thought within which a person is operating. Further, Whitehead's discussion of language includes a number of cogent warning the deficiencies of language, and hence the need for great care in the use of words. In fact, language developed gradually. For the most part we have created words designed to deal with practical problems. Attention focuses on the prominent features in a situation, in particular the changing aspects of things. With reference to such data our words are relatively adequate. However, this issues in an unfortunate superficiality. The enduring, the subtle, the complex and the general aspects of the universe do not have adequate verbal representation. for this reason, Whitehead's position concerning the uses of language in speculative philosophy is stated with pungent directness. The uncritical trust in the adequacy of language is one of the main errors to which philosophy is liable. Since ordinary language does not do justice to the generalities, profundities and complexities of life, it is obvious that philosophy requires new words and phrases, or at least the revision of familiar words and phrases. Proceeding to develop the theme Whitehead contends that words and phrases must be stretched towards a generality foreign to their ordinary usage. In the same vein Whitehead refers to the need to realize that language which is the tool of philosophy needs to be redesigned just as in physical science available physical apparatus needs to be redesigned. But even these words and phrases, stretched or redesigned, are never completely adequate in philosophical speculations. They are, in his opinion, merely a great improvement over ordinary language or the language science, mathematics or symbolic logic.