• Journal of Navigation and Port Research
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• v.45 no.1
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• pp.26-32
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• 2021

In ocean field, the spread of the Fourth Industrial Revolution based on information and communication technology requires high precision and stable PNT&D (Position, Navigation, Timing and Data). As the IMO (International Maritime Organization) and IALA (The International Association of Marine Aids to Navigation and Lighthouse Authorities) are requiring backup systems due to mitigate vulnerabilities and the increase of dependency on GNSS (Global Navigation Satellite System), Korea is conducting a research & development of R-Mode. An DGPS (Differentiate Global Positioning System) reference station that uses MF, an existing maritime infrastructure, and AIS (Automatic Identification System) base stations that use 34 integrity station and VHF will be utilized in this study to avoid redundant investment. Because there are radio shadow areas that display low signal levels in the west sea, the establishment of new R-Mode reference and integrity station will be intended to resolve problems regrading the radio shadow area. Because the frequency has a characteristic in that radio wave transmits well along the ground (water surface) in low frequency band, simulation and measurement were conducted therefore this paper to propose candidate sites for R-Mode reference and integrity station resulted through p wave's propagation characteristics analysis. Using this paper, R-Mode reference and integrity station can be established at appropriate locations to resolve radio shadow areas in other regions.

• Korean Journal of Social Welfare Studies
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• v.41 no.4
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• pp.313-343
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• 2010

The aim of this study is to examine the factors influencing network centrality on women's welfare organizations, and to investigate how the level of network centrality influence the effectiveness of the organization. To achieve this goal, this study conducted a survey on women's welfare organizations in Seoul from March to June, 2009. Network analysis method was used to get each organization's network centrality value. Also, through the Structural Equation Modelling, organizational characteristics predicting network centrality and effect of network centrality on organizational effectiveness. The main results are as follows. First, the significant affecting factors were different between three types of centralities with regards to the type of organization, recognition of resource dependency, attitude of top manager, and established year. Second, the common factors affecting three network centralities were the number of informal ties, accepting feminism as the main organizational philosophy, and the number of qualified staffs. Third, only closeness centrality positively predicted the level of organizational effectiveness among three types of centralities. The faster the organization reaches to other organizations in a network, the organizational effectiveness becomes higher, which means high closeness centrality is more important factor than high degree centrality or high betweenness centrality to increase organizational effectiveness. This result shows social welfare organization should consider changing inter-organizational network strategy from quantity-focused to quality-focused.

• Korean Journal of Social Welfare
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• v.55
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• pp.205-230
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• 2003

This article examines the continuity and change of Korean welfare regime during 1990s. Democracy, globalization and the financial crisis changed the landscape of Korean society as a whole and provided a catalyst for the change of the Korean welfare regime. In order to show how and what changed in Korean welfare regime, this study concentrates on the transformations of income maintenance programmes and social welfare services. The changed aspects are as follow: (1) The ratio of social expenditure to GDP has increased during 1990s and now stood at ten percent level. (2)Rather than backing up the company welfare, government strove to build and expand income maintenance devices for all citizens. (3) The poverty and inequality reduction effects of income maintenance programs are very weak in early 1990s, but they are gradually getting stronger impact on poverty and inequality. But, there are also continuance. (1) In spite of the relative development of income maintenance programs, social welfare services are still poorly designed as before. (2) The expenditure level of social welfare services shows sharp contrast to income maintenance programs and lagged behind the other OECD countries. (3) The expansion of social service sector employment are also not so salient. In 2002, social service employment is only at close to 2.5 per cent of the total employment. Accordingly, korean welfare regime is now characterized by a model which is to curb poverty and inequality by engaging in direct government provision of income maintenance programs, but refrain from expanding social service by relying on net welfare which encourage the provision of services within the family. A implication of our analysis is that the expansion of social welfare Korea saw after 1997 was not really an regime shift. According to the arguments of Peter Hall, first and second order changes in policy do not automatically lead to third order changes which imply regime shift. Policy changes which occurred during 1990s was not accompanied by a shift in policy paradigms. Family dependency in welfare is not yet changed.

• Tunnel and Underground Space
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• v.24 no.5
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• pp.354-365
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• 2014

The horizontal response spectra using the observed ground motions from 15 Fukuoka earthquake series, including main earthquake (2005/03/20; Mw=6.5), were analysed and then were compared to both the seismic design response spectra (Regulatory Guide 1.60), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings (1997). 178 horizontal ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that response spectrum have strong dependency on epicentral distance. The results also showed that the horizontal response spectra revealed higher values for frequency bands at two frequency bands (about 8 - 10 and 16- 20 Hz) than Regulatory Guide 1.60. The results were also compared to the Korean Standard Building Design Spectrum for the 3 different soil types and showed that thehorizontal response spectra revealed higher values for almost all period bands than the Korean Standard Response Spectrum (500 yrs; Return Period; Seismic province 1; SE soil conditions). Through the qualitative improvements and quantitative enhancement of the observed ground motions, the diversity of the observed ground motions should be considered more significantly to improve the certainty of response spectrum.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.227-234
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• 2010

The vertical response spectra using the observed ground motions from the recent more than 30 macro earthquakes were analysed and then were compared both to the seismic design response spectra (Reg Guide 1.60), applied to the domestic nuclear power plants, and to the Korean Standard Design Response Spectrum for general structures and buildings (1997). 176 vertical ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that response spectrum had strong dependency on epicentral distance. The results also showed that the vertical response spectra revealed much higher values for frequency bands above 5~7 Hz than Reg. Guide (1.60). The results were also compared to the Korean Standard Response Spectrum for the 3 different soil types and showed that the vertical response spectra revealed much higher values for the frequency bands below 0.2 second (5 Hz) than the Korean Standard Response Spectrum (SD soil condition). These frequency-dependent spectral values could be related to the characteristics of the domestic crustal attenuation and the effect of each site amplification. However, through the qualitative improvements and quantitative enhancement of the observed ground motions, the conservation of vertical seismic design response spectrum should be considered more significantly for the frequency bands above 5 Hz.

• Journal of Korean Society of Archives and Records Management
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• v.15 no.3
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• pp.55-86
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• 2015

This paper aims to interrogate the layered and dependent structure of the modern and official document management in Korea and Japan from 1894 to 1910. The focus of its study is on documents related with the strategic infrastructure construction in Jeonbuk Province through an analysis from the perspective of historic archival studies. For this study, the chosen period was when Japanese imperialists were on their way to seize the Korean official archival system. As such, our objects are the documents connected with the institution of the Japanese resident-general system in Korea and its infrastructural constructions as part of Japan's war plans of invading the continent. Among others, we examined the documents of the strategic infrastructure construction around Jeonju in Jeonbuk Province by Imperial Japan, in order to wage the Sino-Japanese War and subdue the Donghak Peasant Revolution. More specifically, we illuminate the sources and organization of the approval of the original documents in a higher level that is relevant to the determination of political, financial, and personnel matters, which were designed for the Japanese governmental rule over Korea from the era of the Gabo Reform to the period of the Japanese resident-generals, as well as analyze the actual states of the official documents ina lower level, which were drawn up by Korean government and the resident-general. Consequently, this paper suggests that official Korean archival system at this time must be understood under the context of a layered and dependent structure within the vertical connections between Korea and Japan, and not from the point of view of a national history.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.399-407
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• 2010

The horizontal response spectra using the observed ground motions from the recent more than 19 macro earthquakes were analysed and then were compared to both the seismic design response spectra (Reg Guide 1.60), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings (1997). 130 horizontal ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that response spectrum have strong dependency on epicentral distance. The results also showed that the horizontal response spectra revealed much higher values for frequency bands above 5 Hz than Reg. Guide (1.60). The results were also compared to the Korean Standard Response Spectrum for the 3 different soil types and showed that the vertical response spectra revealed much higher values for the frequency bands below 0.3 second than the Korean Standard Response Spectrum (SD soil condition). These spectral values dependent on frequency could be related to characteristics of the domestic crustal attenuation and the effect of each site amplification. However, through the qualitative improvements and quantitative enhancement of the observed ground motions, the conservation of horizontal seismic design response spectrum should be considered more significantly for the frequency bands above 5 Hz.

• Environmental and Resource Economics Review
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• v.13 no.4
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• pp.593-619
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• 2004

This study analyzes the interfuel substitution of energy demand in Korean manufacturing sector using static and dynamic linear logit models. For the period of 1981~2002, this study uses petroleum, electricity, natural gas and coal as energy sources. According to the empirical results, firstly, the own-price elasticity of coal has been increased steadily even though its elasticity is smallest compared with those of other energy sources. On the other hand, price elasticity of natural gas is largest, but its value has been decreased after 1997. Price elasticities of petroleum and electricity are very stable over the sample period. One of the main features in trends of interfuel substitution is as follows. Substitution effect of a change in price of natural gas on both petroleum and coal has been increased especially after 1997. The implication of the empirical results is summarized as follows: First, the fact of inelastic own-price elasticity of petroleum implies that the dependency of Korean manufacturing sector on petroleum and coal will be persistent even in a sharp fluctuation of petroleum price. Second, the effects of price increase in natural gas on demand for petroleum and coal are very significant. Thus, price decline of natural gas rather than price declines of coal and petroleum could be more effective as an energy price policy for the reduction of $CO_2$ emission. The assessment on this implication will remain for future researches.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.603-608
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• 2010

A study has been conducted experimentally to investigate behavior of ignition and flame spread over metal dust deposits with particle size using by a developed apparatus and thermogravimetric analysis(TGA). Zr, Ta and Mg-Al(90:10 wt%) alloy metal powders including Mg and Ti with different particle size were used. Also we used PMMA(Polymethylmethacrylate) powder to compare the combustion properties to those of metal powders. When dust layers were more than 5 mm in thickness, the dependency of deposit depth on flame spread rate over dust layer was not shown. With decreasing mean particle diameter, flame spread rate over Ti dust layer decreased, while the spread rate over Mg dust layer increased. For mean diameter of $51{\mu}m$, fire spread rate over pure Mg dust layer decreased to about 50 percent in Mg-Al(90:10 wt%) dust layer. The oxide thickness of metal dust used in this study tended to be inversely proportional with the spread rate, and it was quite small for influence with particle size. From the results of TGA for Ti and Mg, weight increasing curves(550 for Mg, 578 for Ta) were observed in the oxidation process, and they seems to be caused by ignition of upper dust layer.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.175-181
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• 2012

Purpose: This study aimed to analyze the influence of aquaplastic mask which is used for the radiotherapy for patients with head and neck cancer on patient positioning by analyzing the results of 2D/2D matching with the use of Exactrac 6D couch system. Materials and Methods: 2D/2D matching-based Image guidance was performed with the use of Exactrac 6D couch system on a total of 14 patients with head and neck cancer who received radiotherapy at this hospital in a period from June 2010 to June 2011. The adjusted 6D values obtained after the image guidance were classified into values related with patients and values not related with patients as to the correlation between the results. Results: In the analysis of the relation of each adjusted value to patients, the coefficient of determination ($R^2$) of longitudinal and pitch direction was 0.76, of longitudinal and yaw direction was 0.48, and of pitch and yaw direction was 0.42 although the coefficient of determination for above factors was 0.03 or less when the dependency of patients was excluded. Conclusion: It was demonstrated that intrinsic factors of aquaplastic mask had influence on the immobilization of patients by aquaplastic mask although various factors related with patients had influence on the immobilization of patients. It is believed that if these factors are adjusted, the treatment of patients with head and neck cancer can be more accurate.