學生指導와 大學圖書館의 役割

鄭東華 仁川敎育大學 學生生活硏究所 1983 學生生活硏究 Vol.2 No.-

유도전동기 드라이브 시스템의 고성능 벡터제어를 위한 PI 및 퍼지 제어기의 비교

정동화,이홍균 순천대학교 2000 순천대학교 자연과학논문집 Vol.19 No.1

For high performance induction motor drives such as mill drives, elevator, spindle drive, NC and so on, accurate position and speed controls are usually required. In high performance drives of induction motors, the position and speed controller usually undergoes a windup because of voltage limitation due to an inverter saturation. This paper is proposes the performance comparison of PI, antiwindup PI and fuzzy controller for high performance vector control of induction motor drive system. An antiwindup PI controller is proposed for PI controller considering inverter saturation. The performance of a fuzzy controller is compared with that of an antiwindup PI controller in an internal loop. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.

유도전동기의 고성능제어를 위한 속도센서리스 벡터제어

鄭東和 순천대학교 공업기술연구소 1993 工業技術硏究所論文集 Vol.7 No.-

Recently, the elimination speed sensor has been one of the important requirement in vector control systems, because the speed sensor spoil the ruggedness and simplicity of induction motor. This paper proposes sensorless vector control for high performance of induction motor. The proposed vector control scheme is based on a rotor flux and speed control which are calculated from the stator voltage and currents with improved flux estimator. The characteristics of vector control employing stator voltage and current generally deteriorate as the speed gets lower because the calculated rotor flux depends on the stator resistance and it is difficult to calculate rotor flux at low speed of standstill. This new control system is that the stator resistance influence reduces on the torque control, and it makes possible to calculate rotor flux at low speed of standstill. These features are verified by the simulation results.

Staphylococcus aureus에 대한 벌꿀의 항균 활성

정동현,백승화 한국식품영양학회 2002 韓國食品營養學會誌 Vol.15 No.2

본 실험은 벌꿀이 항균활성에 미치는 영향을 규명하기 위해 국내산 벌꿀인 밤꿀, 잡화, 아카시아, 재래종 벌꿀과 외국산 벌꿀인 마누카, 클로버, 캐놀라 벌꿀 그리고 인공벌꿀을 각각 12.5%, 25.0%, 50% 의 희석액으로 조제하여 catalase 무첨가 또는 첨가한 경우에 있어서 벌꿀의 Staphylococcus aureus에 대한 항균활성을 agar well diffusion assay로 비교한 바 다음과 같은 결과를 얻었다. Catalase 무첨가의 경우 12.5% 희석한 벌꿀은 마누카꿀> 밤꿀이, 25.0%로 희석한 벌꿀은 마누카 꿀> 밤꿀 > 잡화꿀 > 재래종꿀 > 클로버 꿀 > 아카시아꿀이 , 50.0%로 희석한 벌꿀은 마누카꿀 > 밤꿀 > 캐롤라꿀 > 재래종 꿀 > 잡화꿀 > 클로버꿀 > 아카시아 꿀 순으로 항균활성이 인정되었다 (p >0.01). Catalase 무첨가의 경우 12.5%, 25.0%, 50.0%로 희석한 벌꿀의 생육억제환은 각각 5.85 ~ 6.60 mm, 4.26 ~ 8.27 mm, 5.24 ~ 11.49 mm 범위였다. Catalase 첨가의 경우 12.5%로 희석한 벌꿀은 마누카꿀에서만 항균활성을 나타냈다. 25.0% 로 희석한 벌꿀은 마누카꿀이 밤꿀보다 항균활성이 더 높게 나타냈다 (p > 0.01). 50.0% 로 희석한 벌꿀은 마누카꿀 > 밤꿀 > 클로버꿀 > 캐로라꿀 > 재래종꿀 순으로 항균활성이 높았으며 마누카꿀, 밤꿀, 클로버꿀, 캐롤라꿀, 재래종 꿀 사이에서 유의성이 인정되었다 (p > 0.01). Catalase 첨가의 경우 12.5 %, 25.0 %, 50.0 %로 희석한 벌꿀의 생육억제환은 각각 5.89 mm, 5.01 ~ 6.84 mm, 3.10 ~ 8.28 mm 범위였다. This study examined for the investigation the effect of honey on antibacterial activity. The experimental honey were used the domestics, or chestnut honey, multiflower honey, acassia honey, native honey and the foreign, or manuka honey, clover honey, canola honey, and the artificial honey, made with the diluted solution of each 12.5%, 25.0%, 50.0%. The result of compared the occasion of added-catalase with not added-catalase about the honey's antibacterial activity on Staphylococcus aureus by agar well diffusion assay were as follows. When catalase was not added, manuka honey antibacterial activity was superior to chestnut honey's in the diluted honey of 12.5% and on the occasion of the diluted honey of 25.0%, it was approved in the order of manuka honey > chestnut honey > multiflower honey > native honey > clover honey > acassia honey and the occasion of the diluted honey > multiflower honey > native honey > clover honey > acassia honey and the occasion of the diluted honey of 50.0j% , it was approved in the order of manuka honey > chestnut honey > canola honey > native honey > multiflower honey > clover honey > acassia honey (p > 0.01). The clear zone representing inhibition of growth in diluted honey of 12.5, 25.0, 50.0 % with non-treat catalase ranged from 5.85 to 6.60, 4.26 to 8.27, 5.24 to 11.49 mm, respectively. When the catalase was added, antibacterial activity only showed in the manuka homey of 12.5% and on the occasion of the diluted honey of 25.0% manuka honey's antibacterial activity was superior to chestnut honey (Pp > 0.01). On the occasion of the diluted honey of 50.0 %, antibacterial activity was high in the order of manuka honey > chestnut honey > clover honey > canola honey > native honey (p > 0.01). The correlation was approved significantly among the manuka honey, chestnut honey, clover honey, canola honey and native honey. The clear zone representing inhibition of growth in diluted honey of 12.5, 25.0, 50.0 % with treat catalase ranged from 5.89, 5.01 to 6.84, 3.10 to 8.18 mm, respectively.

CT상의 HU 수치에 따른 상악골 전방견인 효과의 유한요소 분석

정동화 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.6

유한요소분석의 결과는 표현된 물성과 구조, 유한요소의 밀도, 그리고 경계 및 하중조건에 의존하게 된다. 상악견인장치의 사용에 있어 상악의 실제 구조와 밀도를 물성으로 반영하여 새로이 개선된 유한요소 모델과 기존의 방식을 따른 유한요소 모델을 비교하였다. 연구에서 대상이 된 환자는 13세 6개월된 남자 환자였으며 전산화단층사진 촬영으로 얻은 DICOM 영상정보를 개인용 컴퓨터로 옮긴 후 3차원 영상프로그램을 이용하여 3차원 입체영상을 제작하였다. CT상에서 Gray scale을 표현하는 수치인 Hounsfield unit (HU)값을 이용하여 24단계의 물성을 가진 모델(모델1)과 고전적인 방법에 따라 2가지의 물성만을 가진 모델(모델2)을 구성하였다. FH plane하방 45˚ 방향에서 500g의 힘으로 견인하여 다음과 같은 결론을 얻었다. 관골하 능선 후방에 있는 상악골의 부위는 전방부보다 더 넓고, 낮은 밀도를 가진 해면골로 구성되어 있었다. 따라서 같은 견인력을 적용하였음에도 24개의 물성을 가진 모델1의 제1소구치가 모델2의 제1소구치보다 전방과 하방으로의 더 많은 이동이 가능했다. 이에 대한 반응으로, 상악골은 시상면과 전두면상에서 휘어졌고, 소구치를 포함한 전방부위의 상악골이 아래 방향으로 움직이게 되었다. 고전적인 방법의 2개의 물성을 이용한 모델의 경우, 제1소구치 골 주위에서의 전하방 이동이 작게 나타났으며 상악결절부위에서는 상방으로의 이동양상을 보여 결과적으로 이 모델에서는 상악 제1대구치의 전방을 중심으로 시계방향의 회전을 보여 주었다. 따라서 물성 지정의 차이에 따라 유한 요소분석의 결과에 차이를 보였으며 HU 값을 이용했을 때 좀 더 역학적 구조가 잘 표현해 내리라 고려된다. Objective: The result of finite element analysis depends on material properties, structural expression, density of element, and boundar or loading conditions. To represent proper elastic behavior, a finite element mode1 was made using Hounsfield unit (HU) values in CT images. Methods: A 13 year 6 month old male was used as the subject. A 3 dimensional visualizing program, Mimics, was used to build a 3D object from the DICOM file which was acquired from the CT images. Model 1 was established by giving 24 material properties according to HU. Model 2 was constructed by the conventional method which provides 2 material properties. Protraction force of 500g was applied at a 45 degree downward angle from Frankfort horizontal (FH) plane. Results: Model f showed a more flexible response on the first premolar region which had more forward and downward movement of the maxillary anterior segment. Maxilla was bent on the sagittal plane and frontal plane. Model 2 revealed less movement in all directions. It moved downward on the anterior part and upward on the posterior part, which is clockwise rotation of the maxilla. Conclusion: These results signify that different outcomes of finite element analysis can occur according to the given material properties and it is recommended to use HU values for more accurate results.

상업스포츠센터의 조직문화 개념과 유형에 관한 정립

정동화 中央大學校 韓國敎育問題硏究所 2001 韓國敎育問題硏究所論文集 Vol.- No.16

It is necessary to investigate the concept and pattern of the organizational culture in order to offer basic materials inducing the profit gaining, the consumers' satisfaction. and the participation in the daily athletics by means of the understanding of the organizational culture in commercial sports centers . 1.An organization can be defined as a mediative system to accomplish its object by means of the division of labor and the hierarchy of Power, and so the culture has a microscopic meaning, which can be called the refinement of spirit. 2.The organizational culture has two opposite functions; one can be called a progressive for the systematic stability of a society; the other is a retrogressive function which can be thought a condition against an innovation. 3.For the accomplishment of the object, the organizational culture is made up of various forms of value. ideology, creature. strategy, members, circumstances, systems, rules. Consciousness, images, belief, symbols, attitudes, myth, and so on 4. The pattern of the organizational culture can be divided into two dimension; one can be said a maintenance-oriented and activity-oriented dimension; and the other intimate, progressive, conservative , reasonable dimension.

기업화 스포츠센터의 발전과정과 전망에 관한 고찰

정의권,정동화 중앙대학교 스포츠과학연구소 2001 體育硏究 Vol.- No.15

How to connect the quality of life and the promotion of health with the Leisure Age which is given as a by-product of the modern industrial society is the task of the modern Sports Centers. With the previous developmental process, the objective of this research is to map out the strategy of the industrial sports. 1. The development of sports centers have shown rapid growth by the early 1990s since the '88 Seoul Olympics, and especially have expanded much more through the restucturing period in 1994. 2. The regional distribution of sports centers is concentrated in large cities; for example, among the total number of 184 sports centers in the country, Seoul has 96 sports centers, Kyeong-ki 29, Bu-san 15, Tae-gu 9, In-cheon 8. In particular, there is no sports center in Kangwon-do and Cheon-ra Nam-do. 3. The sports centers are forms of enterprise, which are equipped with spacial and functional facilities for the promotion of health. And the marketability has been expanded and subdivided for the customer-oriented marketing. 4. The prospect of sports centers can be understood through the emergence of distinctive small-sized sports centers, the sports centers for the welfare of employees, the net-work of sports centers for the beauty care, and the sprots centers for the medical care and resort.

약계자 영역에서 SynRM의 MTPA를 위한 속도 센서리스 제어

정동화,이정철,이홍균 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

In this paper, a new approach for the SynRM(Synchronous Reluctance Motor) control which ensures producing MTPA (Maximum Torque per Ampere) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using flux observer. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified validity through simulation.

SynRM 드라이브 시스템의 고성능 운전을 위한 최적 효율제어

정동화,이정철 순천대학교 2000 순천대학교 자연과학논문집 Vol.19 No.1

This paper is proposed an optimum efficiency control algorithm for a synchronous reluctance motor which minimizes the copper and iron losses. The constraint in obtaining the optimal angles is constant output torque for given operating speed. The efficiency of the motor can be improved by proposed method especially in the light load condition. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency maximized control scheme. The proposed algorithm allows the electromagnetic losses in variable speed and torque drives to be reduced while keeping good torque control dynamics. Simulation results are presented to show the validity of the proposed algorithm.

유도전동기를 제어하기 위한 인버터의 공간벡터 퍼지제어

鄭東和,朴奎南 순천대학교 공업기술연구소 1998 工業技術硏究所論文集 Vol.12 No.-

A system with fast torque response is very beneficial in applications where direct self control(DSC) is highly desirable. The response of DSC is slower during startup and during change in command torque. Fuzzy control is used for implementation of DSC to improve its slow response. Simulation implementation of the fuzzy logic controller was carried out to verity the behavior of the controller. The simulation results with fuzzy control are compared with those of the conventional DSC. The starting flux and torque response and the responses to the step changes in command torque with fuzzy implementation show a considerable improvement over the conventional control. The steady state responses in both the cases are the same.