• The Journal of Engineering Geology
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• v.32 no.4
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• pp.725-733
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• 2022

This study applied a hydraulic rock splitting system equipped with a hybrid packer to the bench-cut method. The hybrid packer system is an improvement of the packer developed in previous studies; it is designed efficiently to reduce vibration and noise during rock excavation by combining the two functions of inducing hydraulic fractures using injection pressure and then expanding and extending them using a rubber packer. Field experiments assessed the efficiency of rock excavation with respect to the injection conditions; the adjusted experimental conditions included the distance from the free surface and the test holes drilled at the top of the slope and the injection settings. Using a separation of 5 m left some unexcavated parts, but using a separation of 1 m left no unexcavated parts. The hydraulic fractures generated by the injection pressure developed generally parallel to the free surface and expanded and extended as the rubber packer expanded, thus facilitating bench-cut excavation. For hydraulic rock splitting to be broadly applicable to bench-cut rock excavation, it is important to accumulate results from many field experiments conducted under varying experimental conditions for various types of rockmass.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.1-15
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• 2023

In this study, the number of truck traffic accidents was predicted by using Poisson and negative binomial regression analysis to understand what factors affect accidents using expressway data. Significant variables in the truck traffic accident prediction model were continuous driving time, link length, truck traffic volume. number of bridges and number of drowsy shelters. The calculated LOSS rating was expressed on the national expressway network to diagnose the risk of truck accidents. This is expected to be used as basic data for policy establishment to reduce truck accidents on expressways.

• The Korean Journal of Financial Management
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• v.9 no.2
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• pp.295-342
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• 1992

전통적으로 기업이 사채차환(社債借換)(bond refunding)을 행하는 이유는 시장이자율이 발행이 자율보다 낮은 경우 단순히 이자비용을 절감하려는데에 그 동기가 있었다. 이러한 전통적인 이자 비용절감이라는 동기외에 타동기에 대해서 사채차환이 주가수익율과 회사의 위험에 미치는 영향에 관한 실증적인 분석은 거의 없었다고 할 수 있다. 본 연구에서는 사채차환에 대해서 (1) 만기연장가설(滿期延長假說), (2) 이자비용절감가설(利子費用節減假說), (3) 세금절감가설(稅金節減假說), (4) 주당순리익가설(株當純利益假說), (5) 제한조항완화가설(制限條項緩和假說) 및 (6) 레버리지가설(假說)등 6가지의 가설(假說)을 계시하고 사채차환(私債借換)의 공표가 보통주수익율과 위험에 미치는 일반적인 영향을 위의 여섯가지 가설하에서 검증을 하였다. 본 연구의 결과 전통적인 이자비용절감 가설은 주식 가격에 음의 영향을 미치는 것으로 나타난 반면, 오히려 세금절감가설이 강하게 지지되었다. 또한 세금절감을 위한 사채차환이 공표되는 경우 주식베타 및 총수익율분산은 Hamada (1969, 1972)의 견해와 같이 유의적인 양의 변화가 나타났다. 부수적으로 외생변수로서의 기업규모는 초과수익과 역의 관계가 나타났으며, 사채차환의 규모효과가 존재한다는 것을 확인하였다. 본 연구의 다양한 사채차환가설의 초과수익예측이 상호배타적이지는 않으나 시장모형의 베타로 측정되는 주식위험의 변화를 도입하는 경우 이러한 가설들의 효과를 명백히 분리시킬 수 있게 된다. 따라서 횡단면 분석시 전통적인 잔차분석방법에 추가적으로 주가베타 및 총수익율분산을 종속변수로 사용했다는 것이 본 연구의 중요한 공헌이라 하겠다.

• Annual Conference of KIPS
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• 2007.11a
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• pp.59-62
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• 2007

태어나면서부터 건강에 대한 욕구는 현대 사회에서 많은 부분을 차지하게 된다. 물론 어려서부터의 건강관리가 건강 수명 연장은 물론 가장 기본적인 행복한 삶의 추구까지도 보장되고 있는 실정이다. 이를 위해 본 논문에서는 한의학에서 환자의 질병을 진단하기 위해 사용되고 있는 망진(望診)과 청진(聽診)의 이론적 근거를 바탕으로 소아 감기 질환에 대한 진단 시스템을 개발하고자 한다. 특히 소아감기는 일반적으로 제일 발병률이 높은 질환으로 얼굴 부위에 열을 동반한다는 것과 울음소리가 인체의 모든 조음기관과 연관되어 있다는 한의학적 이론을 기반으로 소아의 생체신호를 분석하여 소아 감기와의 상관성을 분석하고자 한다. 이를 위해 소아 감기 환자에 대한 1차 실험으로 얼굴 영상에서의 열 관련 여부에 대한 색상 분석을 행하였으며 2차 실험으로는 조음기관에 대한 성분음을 추출하는 스펙트럼 분석을 수행하였다. 이를 통해 정상 소아와 감기 질환을 앓고 있는 소아 환자간의 차이점을 추출하고자 한다.

• Industry Promotion Research
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• v.6 no.1
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• pp.55-62
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• 2021

This study regards the need for jobs to overcome the poverty of the elderly in an aged society, and as well as researches ways to participate in active economic activities in old age. The results of the study are as follows. First, the legal system needs to be improved. In addition to institutional support for the expansion of jobs for the elderly, improvement of awareness of the elderly and reinforcement of infrastructure such as a delivery system are required, and a legal basis for this is needed. To this end, occupations targeting the elderly must be selected first, and legal procedures must be prepared by the government. Second, there must be social consideration and support for the elderly. Extension of the retirement age plays an important role in enhancing employment for the elderly. Along with the improvement of the legal system, social consideration is required. Therefore, since the elderly policy without social consensus is bound to fail, various support methods that can lead to social support must be devised. Third, the elderly must have a sense of poverty and willingness to rehabilitate themselves. Elderly people should not only ask for their children and social support. The elderly must be able to find a way to become the economic agent themselves. To do this, a basic awareness of the elderly poverty consciousness is needed, and a change of awareness to escape the poverty of the elderly is necessary. Therefore, the elderly need to be self-reliant, and they must choose jobs according to their own abilities. In conclusion, the elderly job program is a part of income increase that solves the poverty of the elderly in the aged society, and the elderly are required to actively participate in economic activities.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.578-585
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• 2015

Track elastic components can be technically and economically efficient when integrated well into track superstructure of a railway network. In such cases, the elastic rail pad is larger than a 800m radius curve provides smooth rail branching and allows for high-speed operation ($V{\geq}160km/h$). High track resistance causes the tamping intervals to stand out because the constantly increasing share of the sleeper pad further extends the increase of the tamping interval and the long grinding period; the engineering and construction of the small curve radius track provides some measures for reducing the solid sounds. Installation of elastic mats under the ballast can have a good effect, particularly in the context of protection against dust during construction or extensive renovation measures when laying new lines. However, such a process requires special attention and proper installation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.655-668
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• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.436-441
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• 2003

The physiochemical properties of wheat flour dough added with onion powder were investigated. The color value of mixed onion powder was added and had low values of lightness and redness, as well as high value of yellowness. Water absorption of the wheat flour dough decreased with the increase in the onion powder. Both development time and stability of the wheat flour dough with onion powder added were less than those of the control. An increase in the added amount of onion powder resulted in an increase of weakness. The maximum viscosity gradually decreased with the increase the amount of onion powder, while the temperature of gelatination did not change. The wheat flour dough extensibility decreased, and the resistance of extension and area under the curve increased in the onion powder. It is of considerable note that the pH of the wheat flour dough decreased in the process of fermentation with an increase in the amount of onion powder.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.281-293
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• 2021

Patients who went through maxillectomy can have severely impaired swallowing, mastication, and pronunciation functions because of palatal defects. Leakage occurs through the nasal cavity while eating, chewing becomes difficult due to the loss of teeth and alveolar ridges, and oral and nasal passages are not separated, leading to hyper-nasal sound, and significantly reducing the quality of life. To prosthetically reconstruct the defect, the weight of the obturator should be reduced as much as possible to minimize dropout because of gravity, and the bulb of the obturator should be properly extended into the defect to get additional retention and stability. In this case of a partially edentulous patient who underwent additional maxillary resection because of tumor recurrence, a metal framework was designed by applying the basic design principles of removable partial dentures. An obturator with improved retention, stability, and support was fabricated through functional impressions. The patient was satisfied with the improved facial expression, mastication, swallowing, and pronunciation, and showed stable occlusion and oral hygiene management during the follow-up period.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.583-595
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• 2014

Currently, Korean transportation policies are aiming for increase of safety and environment-friendly and efficient operation, by avoiding construction and expansion of roads, and upgrading road alignments and facilities. This is revealed by that there have been 22 road expansion projects (30%) and 50 road improvement projects (70%) under the 3rd Five-Year Plan for National Highways ('11~'15), while there were 53 road expansion projects (71%) and 22 road improvement projects (29%) under the 2nd Five-Year Plan for National Highways. For more effective road improvement projects, there is a need of choosing projects after an objective and scientific safety assessment of each road, and assessing safety improvement depending on projects. This study is intended to develop a model for this road safety analysis and assessment. The major objective of this study is creating a road safety analysis and assessment model appropriate for Korean society, based on the HSM (Highway Safety Manual) of the U.S. In order to build up data for model development, the sections thought to have identical geometrical structure factors in 5 lines, Cheonbuk province, were divided as homogeneous sections, and representative values of geometric structures, facilities, traffic volume, climate conditions and land usage were collected from the 1,452 sections divided. In order to build up data for model development, the sections thought to have identical geometrical structure factors in 5 lines, Cheonbuk province, were divided as homogeneous sections, and representative values of geometric structures, facilities, traffic volume, climate conditions and land usage were collected from the 1,452 sections divided. The collected data was processed correlation analysis of each road element was implemented to see which factor had a big effect on traffic accidents. On the basis of these results, then, an accident model was established as a negative binomial regression model.Using the developed model, an Crash Modification Factor (CMF) which determines accident frequency changes depending on safety performance function (SPF) predicting the number of accident occurrence through traffic volume and road section expansion, road geometric structure and traffic properties, was extracted.