• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.12A
• /
• pp.1883-1890
• /
• 1999

Wireless communication in an urban area, the accurate prediction of wave propagation characteristics are very important to determine communication service areas, select optimal base-stations, and design cells, etc. The CCIR model is a propagation prediction model using a shadowing by the buildings in an urban area. This model represent the shadowing rate by the means of the effect of shadowing between base-station and mobile unit in a shaped linear plane. But, This one occurred a lot of prediction error because it did not consider that density area by the buildings and terrain configurations by the hill and mountain on Line-Of-Sight. In this thesis, an improved propagation prediction model is proposed to reduce prediction error. We presents a new equation, which is using the SAS. This equation is associated with the shadow height by the buildings that considers the topology and the number of blocks that can affect the building shadow in the Line-Of-Sight. We measure the received electrical field level of base-station that high density area, medium density area, and low density area, and then compare and analysis the result to prediction of CCIR model and proposed model. The result compared with the measurement, the proposed model has the improvement of 9.71dB in a high density area, 9.66dB in a medium density area, and 4.02dB in a low density area better than the CCIR model. The result compared with the measurement, the proposed model has the improvement of 9.71dB in a high density area, 9.66dB in a medium density area, and 4.02dB in a low density area better than the CCIR model.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.7
• /
• pp.288-292
• /
• 2016

The purpose of this study was to improve the refuge safety area in the high-rise building type. Each simulation was conducted to evaluate the performance of three types in improving the refuge safety area. Targeting the first 63 floors (no refuge safety area), secondly, to target up to the $30^{th}$ floor (refuge safety area on the $30^{th}$ floor, $47^{th}$ floor) specified in domestic laws, and finally, the $20^{th}$ floor (evacuation safety area on the $20^{th}$ floor, $42^{th}$ floor) were considered as targets. Through this analysis, the following results were obtained : The floor for the refuge safety area through simulations showed that the evacuation time is low. It is necessary to improve the floor for the refuge safety area by using the characteristics of the domestic fire fighting vehicle. The first floor for the refuge safety area from the ground floor differs according to the distance and height of the building floor. However, in the case of a business facility it is 15F, and in the case of apartment housing, it is 20F.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.13 no.6
• /
• pp.1-12
• /
• 2010

This study aims at analyzing the development status of surroundings of natural environment conservation areas and securing an adequate distance from development activities to conserve natural environment conservation areas efficiently or developing an improvement plan for setting conservation areas. Findings from the study shows that 1) rather than simply designating a legal natural environment conservation area, a conceptual scope approach of a "core area", "buffer area", and "transition area" such as in zoning of a "biosphere reserve" by UNESCO is recommended; 2) when setting an adequate range in a natural environment conservation area, it should be set by fully considering locational situation and the regional and environmental features of surroundings rather than setting a certain distance uniformly; 3) instead of designating wetlands only as a conservation area, entry and exit areas should be also included as buffer areas and in the case of wild animals, not only habitats but also feeding areas should be designated as conservation areas; and 4) an adequate horizontal separation space is important in the case of ground development, but for natural resources related to subterranean water and geological situation such as wetlands, an adequate vertical separation space should be fully considered.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.2
• /
• pp.301-309
• /
• 2006

In this paper, we show the improved fuzzy c-means clustering method. To improve, we use the double clustering as principal component analysis from objects which is located on common region of more than two clusters. In addition we use the degree of membership (probability) of fuzzy c-means which is the advantage. From simulation result, we find some improvement of accuracy in data of the probability 0.7 exterior and interior of overlapped area.

• Journal of the Korean Professional Engineers Association
• /
• v.38 no.4
• /
• pp.19-22
• /
• 2005

Since 1996, like other countries the PSM(Process Safety Management) System has been applied into chemical plant in Korea in accordance with the Occupational Safety & Health Law section 49 paragraph 2. This report is to point out the status and the area of concern, further suggest alternative measures along with the wide and in-depth idea of improvement and recommendation to prevent from industrial accident.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1994.03a
• /
• pp.83-88
• /
• 1994

The DDC(dynamic deep compection) was carried out the main method of ground improvement for construction of municipal high way. The project area is composed of the municipal waste dumped, demolished building debris, coal ash and industrial waste made between 1983 and 1989. From the result of fileld measurement, it was found that waste landfill was compressed considerably (15 ~ 20% of full depth), and the strength was increased satisfactorily(20 ~ 120% of original N-value, 55 ~ 230% of original dynamic cone penetration resistance). And the chemical inclination of the municipal waste landfill was analyzed for expection and control of settlement.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2007.04a
• /
• pp.243-248
• /
• 2007

This study proposed a procedure to improve the error defection of attached cadastral maps using digital map data. In addition, this study also provided the direction for the accuracy improvement of attached cadastral maps by comparing analysis methods. - such as centroid, Lee Sallee shape index, and area index. The analysis is performed as follows. First, by using centroid measurement, the center point of cadastral maps and attached cadastral maps are compared. Secondly by using Lee Sallee shape measurement, the location accuracy of range area is investigated. Thirdly, by using area measurement, the range area within allowable error scope is verified. Based on analysis, the discrepancy between cadastral maps and the attacked cadastral maps are detected as follows; 98.2% from Lee Sallee shape index, 41.8% from centroid, 15.4% from area index in the whole error.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1766-1784
• /
• 2011

In the past, station-area development projects were proceeded for modernizing the station facilities and improving the customer's convenience facilities by attracting private financing. But the site of station-are a development has a limitation that limits of benefits comparing with initial cost and absence of collateral by constructed the national property. For the advancing business value, merchandising facilities were adopted. There were many problems like coming the loss of city development opportunities. Now, station-area developments are considered the station and city plan. so, they are rapidly rised up the life in the station, need of making cultural space, improvement efficiency, combination and connectivity of transportation system and need of journey to Work Distance. Accordingly, this study suggests the station-area development projects by analysis of market conditions and forecast about housing and office that meets the trend of station-area development and secures feasible business value.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.425-427
• /
• 2008

Active area of dye-sensitized solar cell (DSSC) has an effect on the efficiency of DSSC. As the active area increases, the efficiency goes down in a general way. This is caused by the increase of internal resistance in DSSC. The internal resistances are related to various resistant elements. The charge transfer processes at Pt counter electrode and the sheet resistance of TCO are two of these resistant elements. In this study, we try to divide the active area into several small sections in a large sized cell to reduce these two internal resistant elements. As a result, we find out that the fill factor is increased and then the conversion efficiency is improved as the number of dividing active area into several small sections is increased.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.1
• /
• pp.69-82
• /
• 2016

In this study, Art area -based STEAM education programs that take advantage of the Scratch was to analyze the effect of the development of elementary school students' creativity. The winter break of ${\bigcirc}{\bigcirc}$ university education donation application students 3, 4, 5th grader was verified two research hypothesis to the target. First, Art area -based STEAM education programs will be effective on the development of elementary school students' creativity. Second, Art area -based STEAM education programs will be more effective on the development of the elementary school girls' creativity than the elementary school boys' creativity. Art area -based STEAM education programs is to show a significant difference on the development of elementary school students' creativity, mean change of elementary school girls were remarkable than boys.