• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.409-414
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• 2010

The applications based on geographical location are increasing rapidly in wireless sensor networks (WSN). Recently, various localization algorithms have been proposed but the majority of algorithms rely on the specific hardware to measure the distance from the signal sources. In this paper, we propose the Weighted Multiple Rings Localization(WMRL). We assume that each deployed anchor node may periodically emit the successive beacon signals of the different power level. Then, the beacon signals form the concentric rings depending on their emitted power level, theoretically. The proposed algorithm defines the different weighting factor based on the ratio of each radius of ring. Also, If a sensor node may listen, it can find the innermost ring of the propagated signal for each anchor node. Based on this information, the location of a sensor node is derived by a weighted sum of coordinates of the surrounding anchor nodes. Our proposed algorithm is fully distributed and does not require any additional hardwares and the unreliable distance indications such as RSSI and LQI. Nevertheless, the simulation results show that the WMRL with two rings twice outperforms centroid algorithm. In the case of WMRL with three rings, the accuracy is approximately equal to WCL(Weighted Centroid Localization).

• Journal of KIISE:Databases
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• v.32 no.1
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• pp.56-70
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• 2005

The results of location-dependent queries(LDQ) generally depend on the current locations of query issuers. Many mechanisms, e.g. broadcast scheme, hoarding, or racking policy, have been developed to improve the system peformance and provide better services, which are specialized for LDQs. Considering geographical adjacency of data and characteristics oi target area, caching policy and broadcast scheme affect the overall performance in LDQ. For this reason, we propose both the caching policy and broadcast scheme, which these features are reflected in. Based on the adjacency of data in LDQ, our broadcast scheme use Hilbert curve to cluster data. Moreover, in order to develop the caching policy suitable for LDQ on urban area, we apply the moving distance of a MH(Mobile Host) to our caching policy We evaluate the performance of the caching policy measuring the workload of MHs and the correctness of LDQ results and the performance of the broadcast scheme measuring the average setup-time of MHs in our experiments. Finally, we expect that our caching policy Provides more correct answers when executing LDQ in focal cache and leads significant improvement of the performance of MHs. It also seems quite probable that our broadcast scheme leads improvement of battery life of the MH.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.29-38
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• 2020

Recent research trend of North Korean mining and rock engineering in the past 10 years was analyzed by a literature review of mining and rock engineering papers published in North Korean major mining journals, 'mining engineering', 'geological and geographical science' and 'technology innovation' published in 2008-2017. Basic database was established by organizing bibliographic information and abstract data of research papers in each journal. For each journal, paper submission trend classified by research field was analyzed using the basic database. And further study was conducted to the papers which showed distinguishing methodology and result, to analyze the trend of North Korean mining and rock engineering. The literature study showed a recent trend of quantification and automation in mining and rock engineering researches in North Korea, which seems due to recent changes in North Korea's science and technology policy and deterioration of the mining conditions. The results of this study can be applied in the feasibility studies of North Korea's mineral resource development projects. Future inter-Korean technical cooperation and site survey on North Korean field can secure complement the reliability of this study.

• Journal of Korean Society of Rural Planning
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• v.26 no.4
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• pp.67-79
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• 2020

As globalization, international cooperation has grown in importance. In accordance with this trend, Korea has been receiving high demands from international organizations about expanding the scale of Official Development Assistance(ODA) in line with its improved national status. In addition, in the economic aspect of Korea, the ODA project is expected to provide new growth opportunities in the mid- to long-term by promoting cooperation with developing countries. Uganda is an area with high strategic value due to good agricultural conditions and favorable geographical conditions. The poultry industry is a business that is generally carried out to the Ugandan, but due to economic problems such as initial investment cost, most of them have raised poultry on a small scale which is not enough for main income. This paper proposes the construction and operation plan of adapting to small poultry farms in the village-intensive type to sustainable income for residents in Uganda through ODA project in Korea's agricultural technology. The economic feasibility was analyzed from the long-term perspective when the initial construction cost was supported or not and the poultry species ratio was adjusted in terms of initial and operating costs. Economic analysis was performed using Net Present Value(NPV) method. As of after 10 years, when operating in the form of shifting kuroiler to layers, it was estimated to earn about 700,000 ugx more than when only kuroiler is raised, and it is able to reduce about 14 million ugx from the initial cost than when only raising layers. As of 20 years, the most profitables scenario was the breeding of 100 kuroilers and 400 layers methods. however, this case was anlayzed to be unsuitable for Uganda farmers, with initial costs more than three times higher than the shifting method of the kuroiler to layers. If the initial construction cost is supported by ODA project, the initial investment cost can be recovered in the first year with the shifting method, whereas raising only layers take two years to recoup the cost. In the meantime, when studying livestock industry in Uganda, it was examined by relying on statistical data, but this paper is meaningful in that it predicted how much it is economically effective based on field experience.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.17-35
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• 2004

Svg(Scalable Vector Graphics) is xml graphic standard recommended by E3C as a language based on xml to express two-dimension graphic. Svg can accommodate all Xml's patency and advantage of interoperability, and can used as various web applications being combined with other xml language. In addition, Svg can be applied to the fields of electronic commerce, geographical information, computer education and advertisement because it can produce high quality of dynamic from real-time data. SVG's application can be enhanced by linking with database. In this paper, we discuss how Svg can be utilized in theater reservation system, not just explaining svg's meaning or ability. Svg added graphic advantage in addition to xml's advantage. This means that svg retains not only graphic element but also xml's softness. It becomes easier to designate seats and add them. Current reservation system provided in general only information on time and price for a ticket, but the system using SVG in this paper provides additional information on position, price, cancellation and purchase availability of seat.

• Journal of Korea Water Resources Association
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• v.51 no.10
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• pp.929-939
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• 2018

In North Korea, hydropower which occupies about 63% of power generation is a major electric power source, and North Korea has many advantages in the geographical for developing hydroelectric power. In this study, Information on the basin and dam capacity for 33 potential development site of hydroelectric dam was analyzed using DEM, and potential annual power generation was estimated by applying results of long-term runoff simulation with MWSWAT model for recent 30-year. The potential annual power generation at 33 dam was estimated to be about 28% of the current hydroelectric power in North Korea. In addition, a priority of dam development in each province was assessed by estimating the scale of an industry and prospecting the population change in the future. And a priority for dam development within the province was estimated based on the dam capacity and the potential annual power generation. The priority of each province was ranked in order of Pyeongannamdo, Hamgyungnamdo, Hamgyungbukdo, Hwanghaebukdo, Pyeonganbukdo, Jagangdo, Ryanggangdo, Hwanghaenamdo, and Gangwondo. The results of this study can be used as an initial review data for advancing to hydropower development project in North Korea.

• Korean Journal of Medicinal Crop Science
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• v.14 no.1
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• pp.14-18
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• 2006

This study was carried out to investigate the distribution and habitat characteristics of Boehmeria for utilization and conservation plan of natural agro-plant resources in South Korea. The native habitat of B. longispica Steud., B. platanifolia Fr. et Sav., B. spicata Thunb., and B. tricuspis var. unicuspis Mak. were distributed nearly all areas in South Korea. B. nivea Gaudich. was distributed south of Chungnam but B. pannosa Nak. et Sat. and B. sieboldiana Bl. were partially distributed toward the southern part in South Korea. The average number of plant species growing with Boehmeria in natural habitat was found 124.9 species and Artemisia princeps var. orientalis Hara showed the highest importance value among neighbor species. B. platanifolia Fr. et Sav. and B. spicata Thunb. were the most commonly neighbor species growing with Boehmeria in rate of 49%. Average yearly precipitation and temperature of habitat for Boehmeria were 1100 mm to 1390 mm and $11.3^{\circ}C\;to\;13.7^{\circ}C$ respectively. Soil characteristics of habitat for Boehmeria. were that pH was 5.3 to 7.2 and B. nivea Gaudich. was higher content of organic matter than the other Boehmeria. Content of K and Na were similar among Boehmeria. $P_2O_5$, Ca and Mg were shown a little difference among seven species.

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.75-87
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• 2001

Inter-port competition is fiercer than in the past because of technological evolution in transport systems : the increasing side of containerships implies only a few calls in three or four ports at each end of the trade and the rest of the traffic being served by smaller feederships. It is therefore essential for big ports to be selected as one of these calls by the main shipowners, consortia and alliances to avoid rmarginalisation. In order to compete effectively, many ports have been obliged to modernise and extend considerably its existing ports or to build new port facilities. With the advent of major environmental legislation around the world, however, amenities such as fish and wildlife, clean air and water, access to the waterfront, and view protection took on greater importance. Ports are now being forced to incorporate environmental considerations into their planning and management functions in order to avoid additional costs or timing delays. The aim of this paper is to analyse the port value by which port comparison(or selection) will be made with HFP(Hierarchical Fuzzy Process) method. This was done by extracting and grouping the evaluation factors of port value by port experts : facility and location factor, logistics service factor environment and amenity factor, city and economic factor, and human and system factor. For empirical test of this method, 6 major ports in Northeast Asia were chosen and analysed. The order of importance for five evaluation factors were 1) facility and location factor 2) logistics service factor 3) human and system factor, 4) city and economic factor, and 5) environment and amenity factor. This means that geographical location and logistics services are still being considered as the most important factor to call the port by port users. even though environment and amenity factor shows relatively low figure. Among 6 major ports, Port of Kobe was ranked the first position in a comprehensive evaluation, while Ports of Busan and Kwangyang were 4th and 5th respectively. This implies that Port of Busan should make much efforts to enhance the existing facilities as well as management system.

• Journal of Wetlands Research
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• v.8 no.3
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• pp.67-77
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• 2006

Sedimentological investigations on surface and suspended sediments were performed in Masan Bay of the South Sea in order to reveal recent changes in depositional environments concerning anthropogenic influence. Surface sediments had been classified as 3 sediment facies: mud, slightly gravelly mud, and gravelly mud. In general, mud facies with more than 60% of silt is predominant and slightly gravelly mud facies occurs at the watercourse of bay's central area. The silt-dominant mud faices appears to be predominant before and after dredging. Temperature and salinity changes during one tidal cycle for each season suggest that water columns were stratified without vertical mixing regardless of the season due to weak intensity of tide from the effect of geographical features. The effect of freshwater discharge from the land seems to be insignificant. The strongest current was observed during ebb tide in spring and autumn while observed during flood tide in summer and winter. Net sediment flux (fs) and net suspended sediment transport (Qs) for suspended sediment were determined by remaining drift developed here. Net suspended sediment transport loads were seaward with $62.02{\times}10^3kgm^{-1}$, $31.84{\times}10^3kgm^{-1}$ in spring and fall, respectively, and landward with $18.23{\times}10^3kgm^{-1}$, $3.22{\times}10^3kgm^{-1}$ in summer and winter, respectively.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.11-24
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• 2007

There exist various difficulties in runoff analysis due to many ungauged basins in Korea and the runoff phenomena is also more and more complicated by the change of geologic characteristics due to the urbanization. So, we use GIS technique which is widely used in hydrologic field and cell runoff concept for the fast and effective runoff simulation. This study uses the observations of 6 stage stations in Wi-Cheon watershed and simulates the watershed parameters by using WMS model. We construct DEM by the grids which are consisted based on the criteria of minimum area according to land use. The cell runoff is estimated by an average weighted method using mean annual streamflow and mean maximum daily streamflow obtained from six stage stations. The runoff ratio at arbitrary site is estimated by conducting the direction analysis of streamflow and by removing sinkhole. We compare the simulated and observed runoffs and know that the simulated runoff shows the valid results. So, we could use the geographical information and cell runoff concept for more fast and effective runoff simulation studies.