인버터 TIG용접기의 역률개선에 관한 연구

이정호,김재문,김연충,원충연 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

In this paper, We proposed AC/DC boost converter with high power factor in TIG welder. The proposed power factor correction circuit with UC2854AN acting on constant switching frequency average current control have a three-loop control structure : the inner current loop, the line voltage feedforward loop, and the outer voltage loop. Also, We applied the constant current control strategy to stabilized the output current using the analog PI controller. To demonstrate the practical significance of the proposed methods, some simulation studies and experimental results are presented.

시비방법별 벼 재배에 따른 전과정평가 방법을 적용한 환경영향 평가

신중두,임동규,김건엽,박문희,고문환,엄기철 한국환경농학회 2003 한국환경농학회지 Vol.22 No.1

Consoli가 설명한 것처럼 전과정평가의 개념 및 일반적인 정의에 따르면, 전과정평가는농업생산에 관련된 환경영향을 평가하는데 부합하는 방법이라고 생각되며, 특별히 전과정 평가방법인 Eco-indicator 95는 농업 체재에 대한 환경영향을 분석하는데 적절한 기법인 것으로 입정되었다. Eco-indicator 95 method를 이용하여 지구온난화 및 수계 부영양화와 관련된 시비체계에 따른 벼 재배에 대해 비교할만한 분석체계를 이루었다. 그렇지만 본 연구에서 전화정평가 항목에 기록된 모든 관련 정보가 환경 영향에 고려되지 않았기 때문에 Eco-indicator 95 method를 농업생산 체계에 적용할 때 몇 가지 난제에 부닥친다. Eco-indicator 95 method에 토양 및 자원의 이용과 같은 몇 몇 중요한 환경적인 문제가 포함되지 않았으며, 이 방법의 다른 문제는 환경 평가를 위하여 현장 정밀연구가 수행되지 않았다는 것이다. 그렇지만 본 연구에서 얻어진 생태지표 지수를 이용하여 벼 재배에 따른 시비방법 간의 차이점을 나타내기에 충분하다고 여겨지며, 가장 높은 생태지표 지수를 나타낸 화학비료를 시용한 구에서 가장 큰 환경영향이 관측되었고, 이러한 차이점은 주로 화학비료 투입에 의한 토양중의 높은 인산 함량의 축적 때문인 것으로 여겨진다. 분석한 시비체재는 특별히 지구온난화 보다는 수계의 부영양화의 환경적인 문제에 기여되는 것으로 나타났으므로 질소 시용비율 및 시용기술 이외에 액비 시용에 따른 양분 용탈이 수계 환경에 명확히 영향을 미치는 것으로 나타났다. The suitability of the Life Cycle Assessment (LCA) methodology to analyze'the environmental impact of rice cultivation with different fertilizing systems is investigated. The first part of an LCA is an inventory of parameters used and emissions released due to the system under investigation. In the following step, the Life Cycle Impact Assessment, the inventory data were analyzed and aggregated in order to finally get one index representing the total environmental burden. For the Life Cycle Impact Assessment (LCIA) the Eco-indicator 95 method has been chosen because this is well documented and regularly applied impact assessment method. The resulting index is called Ec -Indicator value. The higher the Eco-indicator value the stronger is the total environmental impact of an analyzed few system. The rice field experiment conducted in middle parts of korea was chosen as an example for the life cycle impact analysis. In this experiment the treatments were consisted of none fertilizer plot (NF), standard fertilizer plot (SF) applied chemical fertilizers based on soil chemical analysis before rice transplan ing, and efflux fertilized plot (EF) applied with pig wastes fermented as the same rates of SF plot as basis on total nitrogen content. The obtained Eco-indicator values were clearly different among the treatments in the rice trial. The total Eco-Indicator values for SF and EF have been observed 58 and 38% relative to the NF, respectively. For all the treatments the environmental effects of eutrophication contributed most to the total Eco-indicator value. The results appeared that the LCA methodology is basically suitable to assess the environmental impact associated with different fertilizer applications for rice cultivation. A comparative analysis of the fertilizing system's contribution to global warming and eutrophication is possible.

스포츠센타 이용객의 구매행동분석

강병길,정문현 牧園大學校 1996 論文集 - 牧園大學校 Vol.30 No.-

The purpose of this study is to define demo-socialogical character of sports center consumer reference to purchase conduct and after all to after base data to marketing strategy income of sports center. To accomplish the purpose of this study, we investigate 420 sports center consumers of Taejon through questionaire who take part in swimming, bowling, and aerobics. And we drew conclusions like these : the demo- socialogical character of sports center users affects to purchase. As synthesizing these results, we find out that : the central area of sports center public relations is the area to takes about 20~30 minutes or foot or by bus ; electronic media for sports center public relations is not effective ; there are lots of cases that he who ever used sports center once or more can effect on public relations of sports center by intreducing to his friends or relations : the reason they use same sports center continuously is the local approachability ; the one using time of sports center is about 60~70 minutes and the cost of it is about 50,000~100,000 won per a month. Also, we found that their purposes of use sports center are not only to dissolve their stress but also to develop their body. These results will contribute to sports industry which subdivides continuously and to scientic and systematic marketing stretage of sports center.

직업적응훈련이 장애인의 인지능력에 미치는 효과에 관한 연구

배은지,이문정 대구대학교 특수교육재활과학연구소 2005 再活科學硏究 Vol.23 No.2

The purpose of this study was to evaluate the effects of work adjustment training for improving cognitive abilities of individuals with disabilities. The degree of changing on cognitive abilities was tested on the effects of changes between before and after that the work adjustment training program for individuals with disabilities. The results were utilized as measurement tools for the improvement of work adjustment training for individuals with disabilities. The followings was the findings obtained through date analysis in this paper. First, as the result of t-test, this verified that work adjustment program has positive effects on increasing the attention, discrimination, reasoning, perception and cooperation of students with disabilities. Second, it was found to significantly affect a sub-factor of attention (middle score of the reaction time), a sub-factor of reasoning (the number of correct answer), a sub-factor of discrimination and perception (the accuracy). Also, a sub-factor of coordination (total average time, error time, percentage error time, and ideal range time) were found to significantly like that. On the other hand, it was not found significantly to influence on a sub-factor of attention (the correct), a sub-factor of reasoning (performance speed), a sub-factor of perception and discrimination (perception speed). 본 연구의 목적은 직업적응훈련이 장애인의 인지능력에 미치는 효과를 알아보고자 대구대학교 재활과학대학 직업재활 임상실습실 훈련생들을 대상으로 직업적응훈련프로그램 실시전과 실시후 인지능력의 변화정도를 파악하였으며, 그 결과는 다음과 같다. 첫째, 인지능력 요인 변화에 있어서 직업에서 요구되는 중요한 인지요인인 주의집중력, 변별력, 추리력, 지각력, 협응능력은 긍정적인 변화가 있는 것으로 나타나 직업훈련프로그램이 인지능력 향상에 긍정적인 영향을 미치고 있다. 둘째, 주의집중력의 하위요인인 반응시간의 중앙값과 변별력, 지각력의 하위요인인 정확도, 추리력의 하위요인인 정답수, 협응능력의 하위요인인 총 평균시간 및 평균오류시간, 퍼센트 오류시간, 이상적 범위시간은 유의미한 차이가 나타났으나 그 외의 주의집중력의 하위요인인 정답과 변별력, 지각력의 하위요인인 인지속도, 추리력의 하위요인인 수행시간에서는 통계적으로 유의미한 차이가 나타나지 않아 일부 하위요인은 직업적응훈련프로그램의 효과가 없는 것으로 나타났다.

환경농업 시범마을 논에서 시비에 따른 무척추동물 개체 수 변화

한민수,신중두,나영은,이남종,박문희,김세근 한국환경농학회 2002 한국환경농학회지 Vol.21 No.2

논의 관리방법에 따른 수서생물상의 변동 양상을 파악하기 위하여 종합적인 환경농업기술 시범 2개 지역의 논 및 하천에서 주기적으로 조사 분석하였다. 논에서의 수서 무척추동물의 총 개체 수는 두 지역 모두 농가관행구에 비해 화학비료 토양검정 시비구에서 62% 이상 높았고 그 다음은 두 지역에서 서로 다르게 나타나 옥천의 경우 농가관행구, 양평은 화학비료+개량재 순으로 많고, 가장 적은 처리는 무비구였다. 수서곤충의 총 개체 수는 토양검정시비구가 농가관행구 옥천 및 양평 각각 328, 45.1/L보다 56%, 69% 더 많았다. 갑각류의 총 개체수는 옥천 지역에서는 토양검정 화학비료구> 화학 비료+개량제구> 농가관행구> 무비구 순으로 많았으며, 양평에서는 화학비료+개량제구>토양검정 화학비료>무비> 농가관행구 순으로서 과다 비료시용구인 농가관행구에서 가장 적었다. 두 지역의 논관류 하천에서 서식하는 수서 무척추동물은 59과 76종이 분류되었고, 미확인종이 14종으로 조사되었으며, 특히 물방개과 중 노란테 콩알 물방개 및 땅콩 콩알 물방개가 채집되었고 양평 지역에서는 날도래 종류가 다양하게 서식하고 있는 것으로 나타났다. 하천지류별 수서 무척추동물 서식밀도는 두 지역 모두에서 상류보다는 하류에서 밀도가 높았으며, 옥천의 연평균 성적에서도 하류에서 1300/0.09 ㎡로 최상류에 비해 172% 더 많은 밀도를 나타냈다. 친환경 농업 실천 2개 지역에서의 논 서식 수서 무척추동물 개체 수 조사 결과 일반관행 농가 논 91.1/L 보다 58% 더 많았다. This study was conducted to survey and identify kinds and population of the freshwater invertebrate fauna according to the managements of paddy rice fields at Ok-Chun and Yang-Pyung. The experiment was conducted in 4 paddy plots; conventional fertilization plot (CF), fertilization by prescription with soil testing with (ST+A) or without soil amendment (ST), and no fertilization as the control. In addition, the freshwater invertebrate fauna was also surveyed at 3 sections of as upper, intermediate and down, in both Jitan and Bungsan stream. The total number of the freshwater invertebrates was higher in the order of ST>CF>ST+A>C and ST>ST+A>CF>C at Ok-Chun and Yang-Pyung, respectively. The population density of aquatic insects was higher in plots fertilized by prescription with soid testing than in the other plots at both demonstration villages. The freshwater invertebrates collected in Jitan and Bungsan stream were identified and classified into 59 families and 90 species, and their population density was highest in the downstream among.

Three-Dimensional Contact Dynamic Model of the Human Knee Joint During Walking

Mun, Joung-Hwan,Lee, Dae-Weon The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.2

It is well known that the geometry of the articular surface has a major role in determining the position of articular contact and the lines of action for the contact forces. The contact force calculation of the knee joint under the effect of sliding and rolling is one of the most challenging issues in this field. We present a 3-D human knee joint model including sliding and rolling motions and major ligaments to calculate the lateral and medial condyle contact forces from the recovered total internal reaction force using inverse dynamic contact modeling and the Least-Square method. As results, it is believed that the patella, muscles and tendon affect a lot for the internal reaction forces at the initial heel contact stage. With increasing flexion angles during gait, the decreasing contact area is progressively shifted to the posterior direction on the tibia plateau. In addition, the medial side contact force is larger than the lateral side contact force in the knee joint during normal human walking. The total internal forces of the knee joint are reasonable compared to previous studies.

A Method for the Reduction of Skin Marker Artifacts During Walking : Application to the Knee

Mun, Joung-Hwan The Korean Society of Mechanical Engineers 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.6

Previous studies have demonstrated the importance of joint angle errors mainly due to skin artifact and measurement errors during gait analysis. Joint angle errors lead to unreliable kinematics and kinetic analyses in the investigation of human motion. The purpose of this paper is to present the Joint Averaging Coordinate System (JACS) method for human gait analysis. The JACS method is based on the concept of statistical data reduction of anatomically referenced marker data. Since markers are not attached to rigid bodies, different marker combinations lead to slightly different predictions of joint angles. These different combinations can be averaged in order to provide a "best" estimate of joint angle. Results of a gait analysis are presented using clinically meaningful terminology to provide better communication with clinical personal. In order to verify the developed JACS method, a simple three-dimensional knee joint contact model was developed, employing an absolute coordinate system without using any kinematics constraint in which thigh and shank segments can be derived independently. In the experimental data recovery, the separation and penetration distance of the knee joint is supposed to be zero during one gait cycle if there are no errors in the experimental data. Using the JACS method, the separation and penetration error was reduced compared to well-developed existing methods such as ACRS and Spoor & Veldpaus method. The separation and penetration distance ranged up to 15 mm and 12 mm using the Spoor & Veldpaus and ACRS method, respectively, compared to 9 mm using JACS method. Statistical methods like the JACS can be applied in conjunction with existing techniques that reduce systematic errors in marker location, leading to an improved assessment of human gait.

A Method for the Reduction of Skin Marker Artifacts During Walking : Application to the Knee

Joung Hwan Mun 대한기계학회 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.6

Previous studies have demonstrated the importance of joint angle errors mainly due to skin artifact and measurement errors during gait analysis. loint angle errors lead to unreliable kinematics and kinetic analyses in the investigation of human motion. The purpose of this paper is to present the loint Averaging Coordinate System (lACS) method for human gait analysis. The lACS method is based on the concept of statistical data reduction of anatomically referenced marker data. Since markers are not attached to rigid bodies, different marker combinations lead to slightly different predictions of joint angles. These different combinations can be averaged in order to provide a "best"' estimate of joint angle. Results of a gait analysis are presented using clinically meaningful terminology to provide better communication with clinical personal. In order to verify the developed lACS method, a simple three-dimensional knee joint contact model was developed, employing an absolute coordinate system without using any kinematics constraint in which thigh and shank segments can be derived independently. In the experimental data recovery, the separation and penetration distance of the knee joint is<br/> . supposed to be zero during one gait cycle if there are no errors in the experimental data. Using the lACS method, the separation and penetration error was reduced compared to welldeveloped existing methods such as ACRS and Spoor & Veldpaus method. The separation and penetration distance ranged up to 15 mm and 12 mm using the Spoor & Veldpaus and ACRS method, respectively, compared to 9 mm using lACS method. Statistical methods like the lACS can be applied in conjunction with existing techniques that reduce systematic errors in marker location, leading to an improved assessment of human gait.

A New Experimental Error Reduction Method for Three-Dimensional Human Motion Analysis

Mun, Joung-Hwan The Korean Society of Medical and Biological Engin 2001 의공학회지 Vol.22 No.5

Average Coordinate Reference System (ACRS) 방법은 인체 보행 분석 시 발생하는 실험오타를 줄이기 위해서 개발되었다. 실험적으로 측정되어지는 운동학 데이터가 인체 모델링 분석을 수행하기 위해서 사용되어지며. 그 모델의 정확성은 그 측정된 데이터에 직접적인 연관 관계가 있다. 그러나, 인체가 보행하는 동안에 피부의 움직임과 골격구조의 변형이 발생하고 또한 운동 분석 실험장비 자체가 가지고 있는 여러 가지의 한계 때문에. 그 실험 데이터에 정확도는 의문시되어 진다 개발된 ACRS 방법은. 인체 운동분석을 수행하는 여러 종류의 시스템에 적용할 수 있는데. 본 연구에서는 ACRS 방법을 광학적으로 추적이 되는 표적을 인체의 각 세그멘트에 붙인 시스템에 적용하였다 ACRS 방법에서는. 각 세그멘트에 붙어있는 각각의 표적들이 독립적으로 그 세그멘트 안에서 국부좌표계의 원점으로 취급되어질 수 있다. 실험 과정에서 발생하는 본래부터의 오타 때문에. 각 원점에서 계산된 Euler angle은 서로 상이한 값을 갖는다 실험 초기에 측정한 보정 세그멘트 기준 프레임의 지식을 이용하면, 각 표적 위치에서 계산된 Euler angles들의 평균값을 계산할수 있고, 그 평균값은 피부의 확장과 회전의 영향을 최소화한 값이다. 운동분석에 일반적으로 적응되는 Euler angle 방법과 개발된 ACRS 방법을 비교하여 보면. ACRS 방법을 사용하였을 때 오차가 줄어들었다 만약에, 보행 실험 데이터에 오타가 존재하지 않는다면, 절대좌표계를 사용한 무릎 관절의 분리와 관통된 거리는 일회 보행구간 동안에 제로가 될 것으로 생각된다. 일반적으로 적용되는 Euler angle 방법을 적용하였을 때, 분리와 관통된 거리는 약 18 mm 가지 분포가 되었고, 개발된 ACRS 방법을 사용하였을 시에는 약 12 mm 까지 분포가 되었다. The Average Coordinate Referenee System (ACRS) method is developed to reduce experimental errors in human locomotion analysis. Experimentally measured kinematic data is used to conduct analysis in human modeling, and the model accuracy is directly related to the accuracy of the data. However. the accuracy is questionable due to skin movement. deformation of skeletal structure while in motion and limitations of commercial motion analysis system . In this study. the ACRS method is applied to an optically-tracked segment marker system. although it can be applied to many of the others as well. In the ACRS method, each marker can be treated independently. as the origin of a local coordinate system for its body segment. Errors, inherent in the experimental process. result in different values for the recovered Euler angles at each origin. By employing knowledge of an initial, calibrated segment reference frame, the Euler angles at each marker location can be averaged. minimizing the effect of the skin extension and rotation. Using the developed ACRS methodology the error is reduced when compared to the general Euler angle method commonly applied in motion analysis. If there is no error exist in the experimental gait data. the separation and Penetration distance of the femoraltibial joint using absolute coordinate system is supposed to be zero during one gait cycle. The separation and Penetration distance was ranged up to 18 mm using general Euler angle method and 12 mm using the developed ACRS.

唯物史觀의 諸 問題点

최정주,정오룡,김병대,문정민 朝鮮大學校 社會科學硏究所 1984 社會科學硏究 Vol.7 No.-