• Journal of the Korean Society of Marine Environment & Safety
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• 제21권5호
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• pp.474-483
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• 2015

In order to understand the seasonal change of phytoplankton as well as the effect of water physico-chemical parameters, we investigated 18 stations in coastal areas of the East Sea in February, May, August and November in 2009. The taxa of phytoplankton observed in this study were classified as 37 Bacillariophyceae, 22 Dinophyceae, 1 Euglenophyceae, 3 Dictyophyceae and 1 Cryptophyceae. Phytoplankton abundance ranged from $1.2{\times}10^3cells/L$ to $246.6{\times}10^3cells/L$(with a mean value of $24.8{\times}10^3cells/L$), the highest biomass was observed in May. The dominant species were Leptocylindrus danicus, Chaetoceros affinis, Pseudo-nitzschia pungens, Thalassionema nitzschioides and etc. Pearson's correlation co-efficient between phytoplankton abundance and other water parameters showed the positive relationships with pH, DO, Secchi-disk depth, and SS, the negative relationships with $SiO_2-Si$. Seasonal patterns of phytoplankton dominant species were affected by the characteristics of water masses based on T-S diagram analysis. In particular, phytoplankton distributional patterns were related with water temperature in May and salinity in August, respectively. According to the result of MDS(Multi-dimensional scaling) using the phytoplankton abundance and species composition, the spatial distribution of phytoplankton were characterized with Ganwon(Group A) and Gyeongbuk(Group B) at the coastal areas of Jukbyeon or Uljin.

• Geophysics and Geophysical Exploration
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• 제6권3호
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• pp.143-152
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• 2003

Among the various geophysical approaches to identify the leakage of leachate with conductivity variation, conventional electrical resistivity survey has been mainly used at waste landfill. We adopted small-loop electromagnetic (EM) survey using multi-frequencies in parallel with electrical resistivity survey to delineate the leakage of leachate through the shallow soil layer at a waste landfill in Jeju Island, and also with self-potential monitoring to detect the streaming potential produced by the movement of leachate. There were no evidences of leakage from waste landfill according to the results of the electrical resistivity survey and SP monitoring, and it was also true from the results of water quality analysis at stream around waste landfill periodically. On the other hand, the results of one-dimensional inversion of spatially-filtered small-loop EM survey data showed the anomalous zone of low resistivity with depth both around and inner waste landfill.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제42권4호
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• pp.111-118
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• 2005

In this paper, we employ the modulation technique for improving the characteristics of beamformer in the low frequencies and thus improving the overall noise reduction performance. In the 1-dimensional uniform linear microphone arrays, we can suppress the narrowband noise component using the delay-and-sum beamforming. But, for the wideband noise signal, the delay-and-sum beamformer does not work well for the reduction of low frequency component because the inter-element spacing is usually set to avoid spatial aliasing at high frequencies. Hence, the beamwidth is not uniform with respect to each frequency and it is usually wider at the low frequencies. In order to obtain the beamwidth independent of frequencies, subarray systems[1][2][3][4] and multi-beamforming[5] have been proposed. However these algorithms need large space and more microphones since they are based on the theory that the size of the array is proportional to the wavelength of the input signal. In the proposed beamformer, we reduce the low frequency noise by using modulation technique that does not need additional sensors or non-uniform spacing. More Precisely, the array signals are split into subbands, and the low frequency components are shifted to high frequencies by modulation and reduced by the delay-and-sum beamforming techniques with small size microphone array. Experimental results show that the proposed technique Provides better performance than the conventional ones, especially in the low frequency band.

• The Journal of Bigdata
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• 제5권1호
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• pp.11-27
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• 2020

In this paper, we developed a big data platform to store, process, and analyze effectively on such education longitudinal study data. And it was applied to the Seoul Education Longitudinal Study(SELS) to confirm its usefulness. The developed platform consists of data preprocessing unit and data analysis unit. The data preprocessing unit 1) masking, 2) converts each item into a factor 3) normalizes / creates dummy variables 4) data derivation, and 5) data warehousing. The data analysis unit consists of OLAP and data mining(DM). In the multidimensional analysis, OLAP is performed after selecting a measure and designing a schema. The DM process involves variable selection, research model selection, data modification, parameter tuning, model training, model evaluation, and interpretation of the results. The data warehouse created through the preprocessing process on this platform can be shared by various researchers, and the continuous accumulation of data sets makes further analysis easier for subsequent researchers. In addition, policy-makers can access the SELS data warehouse directly and analyze it online through multi-dimensional analysis, enabling scientific decision making. To prove the usefulness of the developed platform, SELS data was built on the platform and OLAP and DM were performed by selecting the mathematics academic achievement as a measure, and various factors affecting the measurements were analyzed using DM techniques. This enabled us to quickly and effectively derive implications for data-based education policies.

• Korean Journal of Environment and Ecology
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• 제25권4호
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• pp.621-630
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• 2011

This research examines the push and pull factors of temple stay in Korean national parks. 152 participants of temple stay in Woljeongsa and Guryongsa in national parks in Gangwon-do area completed a survey to access their reasons for participating in temple stay(push factors) and to evaluate how well the visiting experience performed on a selected set of attributes(push factors). Demographics of respondents were similar to the visitor characteristics of Korean national parks. The result of factor analysis identified 6 push factor domains of 'self actualization', 'health enhancement', 'nature assimilation', 'relationship elevation', 'religious experience', and 'leisure experience'. 6 pull factor domains were 'recuperative quality', 'quality of a temple stay program', 'attributes of a temple', 'user convenience', 'tourism experience' and 'accessibility and transportation'. Satisfaction level of temple stay in a national park was very high of 4.71 in a 5 Likert scale. Gangwon- Do was most preferred with the percentage of 89.2 as a suitable area for temple stay in a national park. Findings of multi-dimensional tourism motivations of temple stay in a national park that encompass nature tourism, cultural tourism and religious tourism is expected to provide useful information for the future development of a more competitive temple stay program and a marketing strategy. However, more defined successive research work is required to generalize findings of wellness oriented push and pull factors of temple stay based on nature in national parks.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제26권1호
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• pp.1-7
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• 2013

Structural design and analysis of a coiling arm unloading machine for submarine cable have been originally conducted in this study. Three-dimensional CAD modeling process is practically applied for the structural design in detail. Finite element method(FEM) and multi-body dynamics(MBD) analyses are also used to verify the safety and required motions of the designed coiling arm structure. The effective moving functions of the designed coiling arm with respect to rotational and radial motions are achieved by adopting bearing-roller mechanical parts and hydraulic system. Critical design loading conditions due to its self weight, carrying cables, offshore wind, and hydraulic system over operation conditions are considered for the present structural analyses. In addition, possible inclined ground conditions for the installation of the designed coiling arm are also considered to verify overturn stability. The present hydraulic type coiling arm system is originally designed and developed in this study. The developed coiling arm has been installed at a harbor, successfully tested its operational functions, and finished practical unloading mission of the submarine cable.

• Journal of the Korea Society of Computer and Information
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• 제12권1호
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• pp.177-188
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• 2007

A star schema consists of a central fact table, which is surrounded by one or more dimension tables. Each row in the fact table contains a multi-part primary key(or a composite foreign key) along with one or more columns containing various facts about the data stored in the row. Each of the composit foreign key components is related to a dimensional table. The combination of keys in the fact table creates a composite foreign key that is unique to the fact table record. The composite foreign key, however, is rarely unique to the fact table retold in real-world applications, particularly in financial applications. In order to make the composite foreign key be the determinant in real-world application, some precalculation might be performed in the SQL relational database, and cached in the OLAP database. However, there are many drawbacks to this approach. In some cases, this approach might give users the wrong results. In this paper, an approach to fact table modeling and related MDX query composing, which can be used in real-world applications without performing any precalculation and gives users the correct results, is proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• 제27권6호
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• pp.689-698
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• 2009

SOLAP system integrates and complements the functions of both OLAP and GIS systems. This enables users not only to easily access geospatial data but also to analyze and extract information for decision making. In this study a SOLAP system was designed and implemented to provide urban planners with GIS information when making urban planning decisions. Rapid urbanization in Korea has brought about ill-balanced urban structure as the result of development without detailed analysis of urban plans. Systematic urban planning procedures and automated systems are crucial for detail analysis of future development plans. Data regarding the development regulations and current status of land use need to be assessed precisely and instantly. Multi-dimensional aspects of a suggested plan must be formulated instantly and examined thoroughly using 'what if' scenarios to come up with a best possible plan. The SOLAP system presented in this study designed the dimension tables and the fact tables for supplying timely geospatial information to the planners when making decisions regarding urban planning. The database was implemented using open source DBMS and was populated with necessary attribute data which was freely available from the Statistics Korea bureau homepage. It is anticipated the SOLAP system presented in this study will contribute to better urban planning decisions in Korea through more timely and accurate provision of geospatial information.

• Convergence Security Journal
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• 제19권3호
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• pp.117-126
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• 2019

Historically, the United Nations supported the establishment of the government of the Republic of Korea after liberation and played a decisive role in defending liberal democracy and peace by sending peacekeepers during the Korean War. With the political and military support of the United Nations, the Republic of Korea was able to grow into the world's 10th largest economy today, and now it is time to fulfill its responsibilities and roles to contribute to peace and prosperity in the international community as a middle power. The international peace operations of the United Nations are comprehensive concepts encompassing conflict prevention, peacemaking, peace enforcement, peacekeeping, and peace building, and are implemented in accordance with the Security Council resolutions based on the UN Charter. In order to effectively respond to changes in the international security environment and conflict factors after the post-Cold War, the UN promoted a paradigm shift in international peace operations through the 2000 Brahim Report and the 2015 High-Level Panel Report on UN Peace Activities. Therefore, this study aims to assess the Korean military's international peace operations at a limited level, such as reconstruction assistance and humanitarian assistance, and to present development measures for more active participation as a middle power in the future. To this end, we reviewed the history and specificities of conflict, the conflicting factors after the post-Cold War, and the new paradigm of UN peace operations, focusing on the African region where a number of UN peacekeeping missions are stationed. And it also suggested ways to develop international peace operations that the Korean military should pursue in the future.

• Journal of Ecology and Environment
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• 제29권6호
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• pp.489-494
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• 2006

For the ecosystem conservation and the effective management of naturalized plant species on 261 uninhabited islands distributed in southern and western sea in Korea, we tested the interrelationship between the pattern of distribution and dispersal of the naturalized plant species and the factors of geographical environment of uninhabited islands such as island area, distance from mainland, latitude, longitude, human impacts and habitat diversity. Out of 261 uninhabited islands surveyed, 106 species of the naturalized plants occurred on 229 (87.7%) islands. The naturalized plant species per island averaged 4.6 (SD=4.07) species, and plant species number were higher in southern group (87 species) than in western group (64 species) of islands. Plant species occurred on more than 100 islands were three species : Rumex crispus L. (153 islands), Erigeron annuus Pers. (130 islands), and Conyza canadensis (L.) Cronquist (121 islands), the highest grade '5' of 'degree of naturalization'. The occurrence frequency of 106 naturalized plant species was significantly correlated with island area, distance to mainland, strength of human impacts, and latitude and longitude. Correlation coefficient (r=-0.330) between occurrence frequency and distance from mainland was higher than between occurrence frequency and island area (r=-0.182). The result of path analysis confirmed that plant species number was significantly affected by island area p=0.336) and distance from mainland (p=-0.490), but in this analysis the effect of human impacts on plant species number was very weak (p=0.003). On the basis of these results, strategies on the conservation of ecosystem and the management of naturalized plant species in the uninhabited islands of Korea were discussed.