• Korean Journal of Environment and Ecology
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• v.15 no.3
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• pp.276-285
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• 2001

This report surveyed degradation of forest environment and rehabilitation in Ashio of Japan. Since 1880, a large scale forestry in this area has been destroyed by sooty smoke, and the local government invested heavily to rehabilitate the damaged forestry and denuded mountains. These degradations are due to complex operations, such as sulfurous acid gas from copper refinery, forest fires, steep slope and disadvantageous climate. The rehabilitation works on degraded forestry(2,399ha) were undertaken by tree planting fur three years from 1897. However, forest degradation and disasters were continued, and the total damaged areas were about 2,400~3,000ha in 1956. A Manual labor method, a Helicopter method and also Combination of manual labor and helicopter method had been adopted to rehabilitation works from 1945 to 1996, while 828.19ha of the degraded mountains was rehabilitated. Total investment for those projects was 80 billion yen. A debris control dam, a soil arresting structure, a vegetation-block, a vegetation sack measures and tree planting have implemented significantly fur the method of rehabilitation. An objective of manual labor works is a complete rehabilitation on each place through 3 stage working. The revived green areas accounted fur 49% of the total, and the entire afforest areas are less than 10%. In coming 25 years, an amount of 21.3 billion yen will be invested to rehabilitate 564ha of degraded mountain lands. However, it is impossible to estimate that how long it will take until the whole degraded mountain lands are completely rehabilitated. Rehabilitation works in Ashio may be applicable to environmental restoration and revegetation in the abandoned coal-mine lands of Korea.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.4
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• pp.313-321
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• 2004

Korean government has offcially decided to adopt global geodetic reference system(ITRF and GRS80) from 2007 keeping pace with the spread of GNSS. Industries related with LBS and telematics have called for use of the new coordinate system suitable for GIS/GPS applications. The government also defined the single plane coordinate system that covers entire korean peninsula as UTM-K considering DB-based framework data and user-friendliness, and its defects were corrected while being applied to the building of road framework data. The TM projection, and origin scale factor of plane coordinate system, 0.9996were employed in order to satisfy the single plane coordinate system for the entire Korean peninsula. For the origin of plane coordinate system, longitude of $127^{\circ}$30'00" and latitude of $38^{\circ}$00'00" were applied and, for the initial value of plane coordinate system, N=2,000.000m and E=1,000,000m were used. In addition to considerable savings in costs, it is expected that the UTM-K is applicable for correcting errors occurred during acquisition of geographic information and for aggregating map data produced by different sources. However, during the initial stage for introduction, confusion is forecasted due to the use of two different coordinate systems, which may be minimized by continued publicity and education.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.5-14
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• 2018

Recently the construction of solar plant showed a steady growth in influence of renewable energy policy. It is very important to determine the optimal location and aspect of solar panel using analyzed data of solar radiation to solar plant area beforehand. This study analyzed solar radiation in solar plant area using DEM acquired from UAV geospatial information. Mean solar radiation of 2017 was calculated as $1,474,466W/m^2$ and total solar radiation of 2017 considering solar plant area showed $33,639MW/m^2$ on analyzed result. It is important to analyze monthly solar radiation in aspect of maintenance works of solar plant. Monthly solar radiation of May to July was calculated over $160,000W/m^2$ and that of January to February and November to December showed under $80,000W/m^2$ in monthly solar radiation analysis of solar plant area. Also this study compared with solar radiation being calculated from UAV geospatial information and that of National Institute of Meteorological Sciences. And mean solar radiation of study area showed a little high in comparison with whole country data of National Institute of Meteorological Sciences, because the 93.7% of study area was composed of south aspect. Therefore this study can be applied to calculate solar radiation in new developed solar plant area very quickly using UAV.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.361-370
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• 2021

The purpose of this study was to identify the factors influencing college life stress and life satisfaction of nursing students. The subjects included nursing students from some select areas. The research was conducted in November and December 2020. The data of a total of 227 nursing students were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlations, and stepwise multiple regression analysis. The findings show that college life stress, economic conditions, and interpersonal relationships had significant effects on life satisfaction of the nursing students with an explanatory power of 27.1%. The study examined life satisfaction based on general characteristics and found variations according to college life satisfaction (F=5.88, p=.003), grades (F=7.07, p=.001), interpersonal relationships (F=8.80, p=.000), and economic conditions (F=10.53, p=.000). There was a statistically significant negative correlation between their college life stress and life satisfaction (r=-.436, p<.001). To summarize, these findings raise a need to provide nursing students with a strategy to address economic issues by reducing their academic stress through an improved educational environment, help them keep positive interpersonal relationships through effective communication, and offer them active information such as counseling so that they can achieve life satisfaction.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.75-80
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• 1986

Heterotopic bone formation is a complication which occurs in 0.6 to $61.7\%$ of patients after total hip replacement arthroplasty. We reviewed 4 patients (8 hips) who received postoperative irradiation on their hi ps for prevention of heterotopic bone formation in the Department of Therapeutic of Therapeutic Radiology, Seoul National University versify Hospital from January 1981 through August 1985. Radiation therapy was started 6 to 10 days postoperatively with the dosage of 2,000 cGy given in 10 fractions. As a result, 7 hips had Grade 0 and 1 hip had Grade 1 heterotopic ossification according to modified Blocker system. Our result and review of the literatures strongly support that the postoperative radiotherapy is effective for prevention of heterotopic bone formation in high risk group.

• Journal of KIISE:Software and Applications
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• v.36 no.1
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• pp.92-108
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• 2009

The Princeton WordNet (PWN), which was developed during last 20 years since the mid 80, aimed at representing a mental lexicon inside the human mind. Its potentiality, applicability and portability were more appreciated in the fields of NLP and KE than in cognitive psychology. The semantic and knowledge processing is indispensable in order to obtain useful information using human languages, in the CMC and HCI environment. The PWN is able to provide such NLP-based systems with 'concrete' semantic units and their network. Referenced to the PWN, about 50 wordnets of different languages were developed during last 10 years and they enable a variety of multilingual processing applications. This paper aims at describing PWN-referenced Korean Wordnet, KorLex 1.5, which was developed from 2004 to 2007, and which contains currently about 130,000 synsets and 150,000 word senses for nouns, verbs, adjectives, adverbs, and classifiers.

• The Korean Journal of Financial Management
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• v.22 no.2
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• pp.135-164
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• 2005

We analyze trade and balance records of 10,000 stock investment accounts of individual investors for the period of 1998 to 2003. Individual investors em an annual gross return of 12.3% while the KOSPI and the value weighted composite including KOSDAQ stocks yield 13.6% and 9.7% respectively during the same period. Net return performance is 8.3%, a drop of 5.3% mainly due to heavy trading. Individual investors' annual turnover amounts to over 270 percent. In an analysis of groups formed on the month's end position value, the performance of the top quintile is found comparable to the market while the rest yield significantly lower risk-adjusted returns than the market. We also find evidence rejecting the rational expectation model while supporting the overconfidence hypothesis which states overconfidence leads to a higher level of trading, resulting in poor performance. Individuals tilt their stock investment toward high-beta, small, and value stocks.

• Radiation Oncology Journal
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• v.14 no.3
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• pp.181-189
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• 1996

Purpose : To find the more effective treatment methods that improving the survival of patients with glioblastoma multiforme(GBM), we analyze the prognostic factors and the outcome of therapy in patients with GBM. Materials and Methods : One hundred twently-one patients with a diagnosis of GBM treated at Severance Hospital between 1973 and 1993 were analyzed for survival with respect to patients characteristics, that is, duration of symptom, age, and Karnofsky performance status, as well as treatment related variables such as extent of surgery and radiotherapy. Results : The median survival time(MST) and 2-year overall survival rate (OSR) of the patients with GBM were 13 months and $20.8\%$, respectively. Duration of symptom, age, Karnofsky performance status(KPS), radiotherapy, and extent of surgical resection were associated with improved survial in a univariate analysis. Patients whose duration of symptom was longer than 3 months, had the 2-year OSR of $47.2\%$(p=0.0082), who were younger than age 50, $32.9\%$(p=0.0003) In patients with a KPS of 80 or higher, the 2-rear OSR was $36.9\%$(p=0.0422). Patients undergoing radiotherapy had the 2-year OSR of $22.9\%$(p=0.0030), and surgical resection of $23.3\%$ (p<0.000). A Cox regression model confirmed a significant correlation of duration of symptom, age, radiotherapy, and extent of surgical resection with survival, excluding KPS(P=0.8823). The 2-year OSR were $22.3\%$ and $19.4\%$, combined with chemotherapy or without, respectively(p=0.6028). The duration of symptom of 3 months or shorter, 50 years of age or older, and undergoing stereotactic biopsy only were considered as risk factors, then patients without any risk factors had the MST of 29 months and 2-year OSR of $53.9\%$ compared to 4 months and $0\%$ for Patients who had all 3 risk factors. Most of all treatment failures occurred in the primary tumor site($80.4\%$). Conclusion : The duration of symptom, age, radiotherapy, and extent of surgical resection were a prognostically significant indeuendent variables. To get a better survival, it seems to be reasonable that the study design which improves the local control rates is warranted.

• 전기의세계
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• v.24 no.2
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• pp.99-99
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• 1975

우리나라에서 지상과제인 경제개발, 특히 중화학공업육성에 있어서 전기공업이 치지하는 비중이 큰것을 다시 말할 필요가 없다. 전기공업은 전원개발과 산업발전에 필요한 전기 기기등 중전기공업은 물론, 전선, 케이블, 계장제어기기, 가정용 전기 기기 및 조명기구등 그 범위가 넓고 선진국에서도 대기업이 전기공업을 바탕으로 크게 성장하여 왔다. 80년대에 국민소득 1,000불, 수출 100억불을 목표로 하는 우리나라는 산업의 원동력인 전력수요의 계속적인 증가에 대응하기 위해서 1986년에 1645만KW의 발전설비용량을 갖도록 하는 장기계획이 수립되여 전원개발이 추진되고 있는데 이에 수반되는 막대한 전기기기를 공급하고 나아가서는 수출을 신장하기 위해서 전기공업의 획기적인 발전을 강력히 기도되여야 할 단계에 왔다고 하겠다. 특히 전기공업은 그 부가가치가 크고 기술집약적이어서 정부방침과 같이 국산화방안이 강력히 추진된다면 금후 우리나라에서 크게 발전할 수 있는 업종이라고 하겠다.

• KIPE Magazine
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• v.14 no.1
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• pp.21-25
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• 2009

전력반도체소자는 1947년 트랜지스터의 출현으로 반도체시대가 도래한 이후 사이리스터, MOSFET 및 IGBT 등으로 발전하였다. 개발당시에는 10A 정도의 전류처리 능력과 수백V 정도의 진압저지능력을 가지고 있었지만, 현재에는 정격전류로는 약 8,000A, 정격전압으로는 무려 12kV 급까지 발전되었다. 그러나 전력반도체 소자의 대부분은 실리콘을 윈료로 제작되고 있으며 현재 실리콘의 물성적 한계에 직면하여 고전압, 저손실 및 고속 스위칭화에 대한 새로운 도전이 시작되고 있다. SiC 전력용 반도체는 실리콘 반도체의 이론적 물성한계를 극복할 수 있는 소재로서 80년대 이후 각광받아 왔다. 하지만 대구경의 단결정 웨이퍼 및 저결함의 에피박막의 부재로 90년대 중반까지는 가능성 있는 재료로서만 연구되었다. 90년대 중반 단결정 웨이퍼가 상용화된 이후 단결정 웨이퍼의 대구경화 및 저결함화가 급속히 진전되어 전력용 반도체 소자의 개발도 활기를 띄게 되었다. 본 기고에서는 탄화규소 반도체소자의 기술동향에 대해 소개하고자 한다.