• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.316-322
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• 2005

In this study, the concentration of 17 dioxin congeners in the soil samples near a waste incinerator with respect to distance from incinerator and wind directions were investigated. The effect of PCB source was investigated using the cluster analysis method. The total concentration and I-TEQ concentration of dioxin ranged from 31.065 to 7,257.499 pg/g(dry weight) and from 0.099 to 35.191 pg I-TEQ/g(dry weight.), respectively. There was a weak correlation(not statistically significant) observed between soil concentration and wind direction, and the distance from the incinerator. The reason may be due to the presence of the local combustion sources other than the target incinerator. The fraction of PCDFs and PCDDs was also examined to study the effect of incinerator. The fraction of PCDFs was decreased with the distance from the incinerator. The influence of target incinerator was found within a 500-meter radius. The high concentration in the for site was due to small incinerators and the use of agricultural chemicals such as PCP. To investigate the relationship between soil near the incinerator and the sources, the cluster analysis was conducted using the congener pattern. As a result soil samples were divided into four groups and were qualitatively estimated the influence of sources such as incinerator and PCP by comparing the congener pattern of each roups. It was thought that a cluster analysis was a useful statistical method for the source estimation of dioxin.

• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.479-484
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• 1999

본 연구에서는 사람의 턱 운동과 턱 사이에 작용하는 힘(혹은 압력)을 그대로 나타낼 수 있는 저작로봇을 개발하는 것을 궁극적인 목표로 한다. 이러한 저작로봇이 개발되면, 치과의사가 환자의 턱운동에 나타나는 병변을 진단하고 치료하는데 큰 도움이 될 것으로 사료된다. 또한 , 본 연구에 채택한 병렬기구(parallel mechanism)에대한 순기구학적( forward kinematics)분석은 일반적인 병렬기구의 실계에도 응용될 것으로 기대된다. 본 연구진이 1차적으로 설계한 모델은 베이스와 플랫폼(platform), 그리고 이 둘을 연결하는 3개의 다리로 구성되어 있다. 다리와 플랫폼은 3자유도의 관절로 다리와 베이스는 1자유도의 경첩 관절로 연결되어 있으며, 이 3개의 경첩 관절은 베이스 위의 수평면에서 직선을 따라 움직인다. 경첩 관절의 수평 변위와 세 다리의 길이가 주어졌을 때 플랫폼의 위치와 오리엔테이션을 구하는 순기구학의 해( 解)를 계산해내는 알고리즘을 개발하였다. 이 알고리즘의 특징은 매 순간 오차를 계산하여 이 오차가 줄어드는 방향으로 나아가도록 시간간격(time step)을 조절하는 것이다. 본 알고리즘은 현재 가장 보편적으로 사용되고 있는 뉴튼-렙슨 방법에 비하여 3가지 장점을 나타내고 있다. 우선 , 초기치(initial guess)에 관계없이 수렴한다는 것이다. 또한, 본 알고리즘은 뉴튼-렙슨 방법에 비하여 수렴속도가 훨씬 빠르며, 연산 시간이 매우 짧아져 실제적인 실시간 적용에 적합하다. 마지막으로, 뉴튼-렙슨 방법에서는 여러 개의 해 가운데 어느 곳으로 수렴할 지 예측 할수 없으나 본 알고리즘에서는 초기치에 가장 가까운 해로 수렴한다. 이러한 순기구학의 다중성(multiplicity)문제를 해결하기 위하여 두 개의 조건을 제시하였으며, 이를 적용한 시뮬레이션 결과에 의하면 항상 원하는 해(true solution)에 수렴할 수 있었다.발생량의 감소를 기대 할 수 있는 친환경기술로 유지관리비를 최소화할 수 있는 장점이 있었다. 않은 사람들 중 미래의 검진실행의지에 건강소식지가 영향을 미친 경우는 48.7%였다. 보건교육을 받은 후 유방암 자가검진 실천율은 사업군에서 53.9%로 받기 전의 27.3%보다 증가하였으나 대조군의 경우는 별 차이가 없었다. 연령별로는 60대가 가장 높았고 사업군에서 검진율의 증가분은 30대가 가장 컸다. 교육수준별로는 사업군은 고졸이, 대조군은 전문대졸이 가장 높았고 사업군에서 검진율의 증가분은 고졸에서 가장 컸다. 보건교육 후 유방암과 관련된 건강지식의 정도는 사업군이 3.7점으로 대조군보다 유의하게 높았으며, 유방암 자가검진법을 실천하는 사람들의 동기는 ‘일반 대중매체의 영향’이 가장 많았으며 건강소식지가 동기인 경우도 20.4%였다. 사업군에서 건강소식지가 유방암 자가검진법 실천에 영향을 미친 경우가 79.6%였으며 유방암 자가검진법에 관한 보건교육을 받고 실천하지 않은 사람들 중 미래의 실천의지에 건강소식지가 영향을 미친 경우는 43.6%였다. 이상의 소견에서 지역주민을 대상으로 인쇄매체를 통한 보건교육은 인쇄물만으로도 쉽게 실천 할 수 있는 유방암 자가검진법이 가장 효과적이었으며, 자궁암검진에 관해서도 검진을 받을 수 있도록 지역사회의 보건의료의 하부구조를 정비하여 제도적 장치를 마련하고 정보를 제공한다면 자궁암검진 실천율도 증가할 것이다.고 12.9% 의 발달율을 보여 유의적인 차이를 보이지 않았다. 이상의 결과로 보아 핵이식 수정란을 효율적으로 생산하기 위하여 수핵난자의 세포질에 ionomycin 과 DMAP 의 혼합처리로 탈핵난자의 활성화를 유도하는 것이 효율을 증진시킬 수 있었다고 본다. 또한 공핵수정란을 수정 후 90시간과 114시간 개별 배양하여 할구를 공핵체로 핵이식에 이용하였을 때도 그룹배양에 비하여 효율이 떨어지지 않음을 알 수 있었으며, 수정란의 할구

• Spatial Information Research
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• v.8 no.1
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• pp.51-67
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• 2000

This was preliminary research to develop the mapping method for the Urban Ecological Map. This research provided preliminary evaluation model for ecological conservation. The model was applied to Mt. Kwanak in Seoul, and the Urban Ecological Map was produced and tested. The results are as follows. First, some problems were found in the legal Ecological Map ; insufficient and only qualitative criteria for evaluation of the conservation value in an urban area, and exclusion of the areas designated by other was laws. Secondly, in order to improve the evaluation criteria for Ecological Map, some missed sites should be added to the legal list of valuable sites. Those are needed for ecological restoration, conservation of wildlife habitats managed by a city government , and establishment of eco-corridor. Third, the efficient mapping process for Urban Ecological Map must have two steps. On the first step an ecological evaluation should be done based on pure conservation value. On the second one the Ecological Map for legal action control should be made. And the Analytic Hierachy Process is considered as a Helpful technique for improving the objectivity of evaluation model. Fourth, the legal action control system for Urban Ecological Map should be reviewed.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.591-600
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• 1998

The purpose of this study was to investigate the root resolution and repair pattern of human teeth according to the force magnitude, direction and duration during the initial leveling and alignment phase. 40gms to 500gms of force applied to the 37 experimental teeth with duration of 3 weeks to 7 months. Then, the experimental teeth were extracted. 13 control teeth were extracted without treatment. The results are as follows: 1. $59.5\%$ of 37 teeth exhibited root resorption. The initial resorption site was visible at the apex within 3 weeks with 100 gms samples, and the initial repair site was visible at the apex within 3 months with 400 gms samples. 2. Number of resorbed teeth increased with the duration of the force. 3. The depth of the resorption increased with the magnitude of the force. 4. The areas of resorbed root corresponded with the loading pattern. 5. The areas of resorbed root were highly correlated with the magnitude of the force. The result of this study suggest that root resorption could occur during the initial leveling and alignment phase, These initial injuries are all small and insignificant. It is the extensive type of apical root resolution that must be regarded as deleterious to the function and stability of the tooth moved. During the initial leveling and alignment phase lighter force of the interrupted type and short treatment period would be favorable with regard to avoidance of root resorption and repair of resorbed root surface.

• Management & Information Systems Review
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• v.32 no.2
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• pp.165-191
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• 2013

A long debate has been made about whether job satisfaction facilitates or impedes union participation. This study analyzed the moderating effect of union instrumentality in the relationship between job satisfaction and union participation. The data collected from 826 employees of 22 workplaces were empirically evaluated. The result of the research revealed that both positive effect and negative effect were observed in the relationship between job satisfaction and union participation. The positive effect was noticed in the direct influence of job satisfaction on the union participation. However, given the interaction between job satisfaction and union instrumentality, the job satisfaction showed the negative effect on the union participation. Based on this result, we can conclude that the direct influence of job satisfaction on the union participation supports dissonance theory about the union participation and the interaction effect between job satisfaction and union instrumentality confirms the utility theory. The present study indicates that the effect of union participation is more reinforced when job satisfaction and union instrumentality are closely connected than when job satisfaction independently affects union participation. Thus, the result implicates that for the revitalization of the labor union, the organization needs to offer a variety of services to satisfy the expectation of whole union members in practical terms instead of concentrating on the labor movement for the political struggle. This point says a lot for a new direction of labor movement.

• Korean Journal of Social Welfare
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• v.67 no.2
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• pp.137-159
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• 2015

This longitudinal study examined the influence of substandard housing conditions and housing affordability on physical and mental health. Using data from the Korea Welfare Panel Study, this study followed 8,583 adults who continued to participate in the survey from 2009 to 2013. Multivariate analyses involved linear and logistic regression models with the hybrid method that incorporates both fixed and random effects. Results show that substandard housing conditions and excess housing cost burden had significant adverse effects on adults' mental health (e.g., depressive symptoms). About one fourth of the entire sample and one third of those in poverty reported having lived in substandard housing conditions. Additionally, nearly one fourth of those in poverty reported having experienced excess housing cost burden, which is 4 times greater than that of the entire sample. Our findings show that a substantial proportion of individuals, particularly among the poor, have a difficulty in accessing to decent, affordable housing, and that housing assistance may have additional benefits of improving the mental health of individuals with housing issues.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.2
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• pp.200-208
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• 2003

This paper proposes a separation and feature extraction of image signals using the independent component analysis(ICA) based on neural networks of efficient learning rule. The proposed learning rule is a hybrid fixed-point(FP) algorithm based on secant method and momentum. Secant method is applied to improve the performance by simplifying the 1st-order derivative computation for optimizing the objective function, which is to minimize the mutual informations of the independent components. The momentum is applied for high-speed convergence by restraining the oscillation in the process of converging to the optimal solution. The proposed algorithm has been applied to the composite images generated by random mixing matrix from the 10 images of $512\times512$-pixel. The simulation results show that the proposed algorithm has better performances of the separation speed and rate than those using the FP algorithm based on Newton and secant method. The proposed algorithm has been also applied to extract the features using a 3 set of 10,000 image patches from the 10 fingerprints of $256\times256$-pixel and the front and the rear paper money of $480\times225$-pixel, respectively, The simulation results show that the proposed algorithm has also better extraction speed than those using the another methods. Especially, the 160 basis vectors(features) of $16\times16$-pixel show the local features which have the characteristics of spatial frequency and oriented edges in the images.

• The Journal of Korean Association of Computer Education
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• v.8 no.3
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• pp.43-60
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• 2005

Teaching computer and ICT skills in K-12 helps to bridge the digital divide of the students at the minimum cost, and provides them with a chance of getting a Quality of life as well as a Quality of work in the future. From examining the education policies of U.S., EU, Canada, and other countries, concerning computer education, several factors, including vision and national-level policy, Quality of manpower, needs for computer-related technology, structure of IT industry, overall demand for IT specialists, have been identified as those with major impacts on the curriculum of computer education. Based upon the analysis of domestic key factors, three levels of computer education program are suggested. At the most basic and least controversial level, basic ICT-skill program for effective learning needs to be provided for every student. Next level is concerned with improving the Quality of life and work. A program for introductory level of computer science can be provided as extra-curricular classes for bright and eager students, who might want to be computer expert or specialists.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.75-86
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• 2017

The facial palsy is one of the most common illness in Western-Korean collaborative treatment (hereinafter "collaborative treatment"). The purpose of this study is to analyze facial palsy patients'collaborative treatment use patterns. By analysing the 2014 National Health Insurance Review and Assessment Patient Sample Data (NPS 2014) with the episode of care unit, we have found the following results. First, the collaborative treatment is preferred by patients over 50 years old and female. Second, western medicine mainly focuses on diagnosis and medical examination while korean medicine and collaborative treatment focus more on treatment activity. Third, western medicine showed the shortest treatment period, followed by korean medicine and collaborative treatment. However, the cost of medical treatment per day is highest in western medicine. The analysis of the use patterns of collaborative treatment shown in the study is expected to provide a direction for the development of clinical practice guidelines and the establishment of medical policies in the future.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.88-102
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• 2006

In multimedia information retrieval, multimedia data are represented as vectors in high dimensional space. To search these vectors effectively, a variety of indexing methods have been proposed. However, the performance of these indexing methods degrades dramatically with increasing dimensionality, which is known as the dimensionality curse. To resolve the dimensionality curse, dimensionality reduction methods have been proposed. They map feature vectors in high dimensional space into the ones in low dimensional space before indexing the data. This paper proposes a method for dimensionality reduction based on a function approximating the Euclidean distance, which makes use of the norm and angle components of a vector. First, we identify the causes of the errors in angle estimation for approximating the Euclidean distance, and discuss basic directions to reduce those errors. Then, we propose a novel method for dimensionality reduction that composes a set of subvectors from a feature vector and maintains only the norm and the estimated angle for every subvector. The selection of a good reference vector is important for accurate estimation of the angle component. We present criteria for being a good reference vector, and propose a method that chooses a good reference vector by using Levenberg-Marquardt algorithm. Also, we define a novel distance function, and formally prove that the distance function lower-bounds the Euclidean distance. This implies that our approach does not incur any false dismissals in reducing the dimensionality effectively. Finally, we verify the superiority of the proposed method via performance evaluation with extensive experiments.