홀로그래픽 고분자 분산 액정을 이용한 홀로그램 이중 초점 렌즈 제작

이정훈,성기영,이상조,김기현,조영걸,곽종훈,송재봉,이윤우,Lee, Jung-Hoon,Sung, Gee-Young,Lee, Sang-Jo,Kim, Ki-Hyun,Joh, Young-Gul,Kwak, Chong-Hoon,Song, Jae-Bong,Lee, Yun-Woo 한국광학회 2003 한국광학회지 Vol.14 No.2

다기능성 아크릴레이트 단량체와 네마틱 액정 등을 혼합한 홀로그래픽 고분자 분산 액정 박막을 제작하고 액정의 농도와 피부에서 인가한 교류 전기장 등에 대한 실시간 회절효율을 측정하였다. WPDLC 박막에 기록된 홀로그램은 적절한 교류 전기장의 on/off에 의해 가역적으로 소거와 재생이 가능함을 보였다. 이러한 전기광학 특성을 이용하여 30 cm와 40 cm의 이중초점을 갖는 홀로그램 렌즈를 제작하였다. We Have fabricated a holographic polymer-dispersed liquid crystal (HPDLC) thin film, which is composed of multifunctional acrylate monomer blended with the nematic liquid crystal mixture, and then investigated the real-time diffraction efficiencies for various amounts of liquid crystals and applied AC electric fields. It is experimentally shown that the holographic gratings recorded in the HPDLC film can be reversibly erased and reconstructed by switching on and off an appropriate applied AC electric field. By use of these electro-optic properties we have developed bifocal holographic lenses having two different focal lengths of 30cm and 40 cm.

중환자실 간호사의 이직의도 예측요인

이정훈Lee, Jung Hoon),송영숙(Song, Yeoungsuk) 병원간호사회 2018 임상간호연구 Vol.24 No.3

Purpose: The purpose of this study was to understand morality identity, occupational stress and authentic leadership and identify factors contributing to turnover intention among intensive care unit (ICU) nurses. Methods: Data were collected from 230 nurses at the university hospitals in Daegu, Ulsan and Busan between February 15 and March 23, 2017. Instruments measuring turnover intention, moral identity, occupational stress, and authentic leadership were utilized. Statistical analysis included t-test, ANOVA, Pearson correlational analysis, and hierarchical regression analysis. Results: A total of 207 nurses in ICU participated in this study. The power of explanation with age and dependents on turnover intention was 4.1%. With inclusion of occupational stress, moral identity, and authentic leadership factors put into the model, further 20.4% was explained. The explanatory power of the turnover intention in the final model was 23.6% (F=11.63 p<.001), and occupational stress was the key factor explaining turnover intention (β=.28, p<.001). Predictive factors contributing to turnover intention were age, occupational stress, moral identity, and authentic leadership in final model. Conclusion: These findings demonstrated occupational stress, moral identity and authentic leadership as critical factors contributing turnover intention of ICU nurses. It is necessary to promote nursing manager’s authentic leadership, and to encourage moral identity in ICU nurses. In addition, providing intervention programs to reduce occupational stress for ICU nurses is necessary.

닭고기 수출 활성화를 위한 무슬림 시장 진출 방안

이정훈,김하정,김나경,박정민,김진만,Lee, Jung-Hoon,Kim, Ha-Jung,Kim, Na-Kyeong,Park, Jung-Min,Kim, Jin-Man 한국축산식품학회 2014 축산식품과학과 산업 Vol.3 No.1

A New Robust Continuos VSCS by Saturation Function for Uncertain Nonlinear Plants

이정훈,Lee, Jung-Hoon The Institute of Electronics and Information Engin 2011 電子工學會論文誌-SC (System and control) Vol.41 No.4

본 연구에서는 수정된 상태변수 의존 비선형 형을 바탕으로 부정합조건 불확실성과 정합조건 외란을 갖는 비선형 시스템의 제어를 위한 새로운 둔감한 비선형 연속 가변구조제어기의 체계적인 설계를 제안한다. 부정합조건 불확실과 정합조건 외란 비선형 시스템을 상태변수 의존 비선형 시스템 형으로 표현한 후 체계적인 둔감한 새로운 제어기 설계를 한다. 대상 시스템의 확장을 위하여 비선형 시스템 함수의 불확정성을 상태변수 의존 항과 비의존 항 두 부분으로 나눈다. 본 비선형 제어는 제어 결과 동특성을 선형으로하기 위하여 그리고 슬라이딩 모드 존재조건을 쉽게 만족시키기 위하여 변환된 선형 슬라이딩 면을 선정한다. 선정된 슬라이딩 면 위에 슬라이딩 존재조건과 폐루프 지수 안정성을 만족하는 제어입력을 제안한다. 정리를 통하여 증명한다. 본 제어의 실용성을 위하여 가변구조제어의 내재된 특성인 제어입력의 불연속성을 극적으로 개선한다. 설계 예와 시뮬레이션 연구를 통하여 제안된 제어기의 유용성을 입증한다. In this note, a systematic design of a new robust nonlinear continuous variable structure control system(VSCS) based on the modified state dependent nonlinear form is presented for the control of uncertain affine nonlinear systems with mismatched uncertainties and matched disturbance. After an affine uncertain nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a new robust nonlinear VSCS is presented. The uncertainty of the nonlinear system function is separated into the tow parts, i.e., state dependent term and state independent term for extension of target plants. To be linear in the closed loop resultant dynamics and in order to easily satisfy the existence condition of the sliding mode, the transformed linear sliding surface is applied. A corresponding control input is proposed to satisfy the closed loop exponential stability and the existence condition of the sliding mode on the linear transformed sliding surface, which will be investigated in Theorem 1. For practical application, the discontinuity of the control input as the inherent property of the VSS is improved dramatically. Through a design example and simulation studies, the usefulness of the proposed controller is verified.

응급실을 내원한 구강악안면외과 안면골 골절 환자의 변화에 대한 비교 연구

이정훈,김용덕,신상훈,김욱규,김종렬,정인교,Lee, Jung-Hoon,Kim, Yong-Deok,Shin, Sang-Hun,Kim, Uk-Kyu,Kim, Jong-Ryoul,Chung, In-Kyo 대한악안면성형재건외과학회 2005 Maxillofacial Plastic Reconstructive Surgery Vol.27 No.2

Although there have been many clinical studies about the facial trauma in the recent as well as in the past, severity and frequency of facial trauma are reported multifarious. It seemed to be because of variety of social, cultural, and environmental factors, and the view point of investigators. In this study, we investigated about the patients visiting emergency room during recent 5 years(1999-2003), and compared with retrospective study during former 5 years(1992-1996) in Dept. OMS Pusan Univ-Hospital. We are assessed the cause, type, demographic ect. And analyzed alterations of facial bone fractures during past 2 periods. the results were as follows. The total number of patients was increased slightly. 429 patients treated for maxillofacial fractures between January 1992 and December 1996 and 466 patients treated between January 1992 and December 1996. The male-to-female ratio reduced in the second period by a factor of 0.7. Patients in the age groups of 10-19 years and 20-29 years increased by a factor of 4.2 and 7.9 in the second period. Assaults and falls in the second period decreased by a factor of 15.4 and 7.9. But, traffic accidents and slip downs in the second period increased by a factor of 6 and 6.6. The mandibular fractures(70.6%) showed the highest incidence, followed by zygomatic bone and arch fractures(7.5%), maxillary bone fractures(4.0%), and nasal bone fractures(4.0%). In the second period, the mid-face fracture was increased slightly. So, the mandibular fractures(69.0%) followed by maxillary bone fractures(12.9%), zygomatic bone and arch fractures(8.0%), nasal bone fractures(7.0%). Ramus fractures and body fractures of mandible was increased slightly in the second period.

Ta 치환에 따른 비납계 (Na_0.53K_0.47)(Nb_1-xTa_x)O₃ 세라믹의 압전 및 유전 특성

이정훈,류경현,성연수,조종호,송태권,김명호,Lee, Jung-Hoon,Ryu, Gyung-Hyun,Sung, Yeon-Soo,Cho, Jong-Ho,Song, Tae-Kwon,Kim, Myong-Ho 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.5

Pb(Zr,Ti)$O_3$ (PZT) based ceramics with superior piezoelectric properties have been extensively used in various domestic and industrial appliances. However, PZT ceramics causing environmental contamination and health problems need to be eventually replaced by any of Pb-free materials. $(Na_{0.53}K_{0.47})(Nb_{1-x}Ta_x)O_3$ (NKNT), one of Pb-free piezoelectric ceramics, has long been known but its properties are not fully understood and developed. In this study, dielectric and piezoelectric properties of Pb-free NKNT ceramics were studied with Ta substitution for B-site at x = 0~0.6. It was found that polymorphic phase transition (PPT) between orthorhombic and tetragonal phases was notably influenced by Ta substitution. The highest piezoelectric coefficient ($d_{33}$) of 284 pC/N was occurred at x = 0.45.

공통현 기반 삼변측량 보정 알고리즘 및 복합 측위 시스템 개발

이정훈,박부곤,김용길,최지훈,김정태,배경훈,Lee, Jeonghoon,Park, Bu-Gon,Kim, Yong-Kil,Choi, Ji-Hoon,Kim, Jung-Tae,Bae, Kyung-Hoon 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.3

공통현을 이용한 삼변측량 기반 실내 측위의 경우 각 AP로부터 이동체까지의 거리를 구하여, 각 AP별로 해당 거리를 반지름으로 하는 원을 이용하여 원들의 둘레가 교차 되는 접점들을 이용하여 이동체의 위치를 예상한다. 거리 오차로 인하여 원 간의 접점이 생성되지 않는 경우, 위치 예상에 실패하게 된다. 본 논문에서는 이를 개선하기 위한 알고리즘을 제안하였는데, 거리에 따라 반지름의 크기에 비례한 값을 임의로 추가하여 강제로 접점을 생성하여 예상 위치를 생성한 뒤, 해당 원의 반지름에 추가된 임의 값과 원점으로부터, 거리에 따른 보정을 하였다. 기존 삼변측량의 거리 오차로 인한 좌표 생성 실패 비율과 좌표 측위 오차를 최소화하는 발전된 알고리즘을 제안하고 시스템을 제작하여 성능을 분석하였다. Indoor positioning based on trilateration using common chord estimates location of a mobile subject by using intersection points between each circles which the radius is same as distance between the mobile subject and each radio-frequency transmitter. However, if the intersection points are not found due to error of the distance measurement, it causes failure of estimating the mobile subject's location. To prevent this case, numbers which is proportionate to radius of each circles, are temporarily added to each distances in order to lengthen radius of the circles. Although the estimated location includes error due to the radius extension, it is corrected again by the added value and distance from reference point. With introduction of the advanced correction algorithm, potential issues of existing trilateration such as failure of estimating location and distance measurement error will be minimized.

A New Integral Variable Structure Regulation Controller for Robot Manipulators with Accurately Predetermined Output Performance

이정훈,Lee, Jung-Hoon Institute of Korean Electrical and Electronics Eng 2004 전기전자학회논문지 Vol.8 No.1

본 연구에서는 고도의 비선형 로봇 매니플레이터를 위한 새로운 적분 가변 구조 제어기를 설계하였다. 특수 적분 슬라이딩 면과 외란 관찰기를 이용한 사전 성능을 갖는 개선된 레귤레이션 제어이다. 어떠한 리칭 구간도 없이 주어진 초기조건부터 원점까지 슬라이딩 궤적을 정확히 사전 결정하기 위하여 특수한 초기 조건을 갖는 적분 변수를 갖는 슬라이딩 면이 채택되었다. 그리고 외란 관찰기를 사용한 연속 입력은 큰 계산 부하 없이 사전 추적오차 범위내의 사전에 결정된 슬라이딩 궤적을 추적하게 한다. 사전에 결정된 슬라이딩 궤적을 사전에 결정된 추적 오차의 성능은 슬라이딩 면의 값과 슬라이f딩 출력의 오차와 관계와 페루프 안정성과 함께 두 개의 정리를 통하여 명확히 검진되었다. 제안된 레귤레이션 제어기의 설계는 성능 설계와 강인성 설계로 각 독립 링크 상에 분리된다. 제안된 알고리즘의 유용성은 매개변수 불확실성과 페이로드 변동하의 이 축 로봇의 레귤레이션 제어에 대한 시뮬레이션 연구를 통하여 무 리칭 구간, 무 오버슈트, 사전 추적 오차를 갖는 사전 결정 출력, 용이한 출력 가변성, 설계 단계의 분리 등의 관점에서 입증되었다. In this paper, a new integral variable structure regulation controller(IVSRC) is designed by using a special integral sliding surface and a disturbance observer for the improved regulation control of highly nonlinear robot manipulators with prescribed output performance. The sliding surface having the integral state with a special initial condition is employed in this paper to exactly predetermine the ideal sliding trajectory from a given initial condition to origin without any reaching phase. And a continuous sliding mode input using the disturbance observer is also introduced in oder to effectively follow the predetermined sliding trajectory within the prescribed accuracy without large computation burden. The performance of the prescribed tracking accuracy to the predetermined sliding trajectory is clearly investigated in detail through the two theorems together with the closed loop stability. The design of the proposed IVSRC is separated into the performance design and robustness design in each independent link. The usefulness of the algorithm has been demonstrated through simulation studies on the regulation control of a two link manipulator under parameter uncertainties and payload variations, in view of no reaching phase, no overshoot, predetermined response with prescribed accuracy, easy change of output performance, separation of design phase, and so on.

Tilt-rotor 항공기 동력계통 중량 추정에 대한 상쇄연구

이정훈,Lee, Jung-hoon 항공우주시스템공학회 2014 항공우주시스템공학회지 Vol.8 No.4

This paper presents the trade-off study of conducting a survey of the weights for various kind of propulsion systems installed in the Smart Unmanned Aerial Vehicle TR-100, a tilt-rotor vehicle, which is developed by Korea Aerospace Research Institute, in order to predict the appropriate propulsion system for present and future Personal Air Vehicle, which has single mode and vertical take-off & landing. In order to perform the trade-off study, we set the requirements that the vehicle hovers for 1 hour with 1,000 kg maximum take off weights. In this study, the power systems are classified engine, which uses the fossil fuel - turboshaft engine, piston engine, diesel engine and rotary engine, and electric motor with fuelcell or Li-Ion battery. The results of trade-off study shows the power systems using fossil fuel are superior to using fuelcell or Li-Ion battery for weight of propulsion system. Also turboshaft engine is the best power system for the aspects of system weight, and the nexts are rotary engine, piston engine, diesel engine, electric motor with Li-Ion battery, and electric motor with fuelcell.

항공기 피치 조종력 비행시험

이정훈,Lee, Jung-hoon 항공우주시스템공학회 2014 항공우주시스템공학회지 Vol.8 No.3

This paper presents the procedures and the results of the pitch control force via flight test for a light airplane in order to make out the stability of the aircraft and the compliance with concerned regulation. The flight test procedures were determined in order to obtain the aircraft type certification. The instrumentation equipments including airspeed indicator, accelerometer, and pitch control force measurement tools are used to perform the flight test. For the flight test, the airspeed and the pitch control force with related normal acceleration are measured sustaining turn flight with bank angle derived from trim speed. The flight test results showed that the handling qualities of the airplane are complied with the KAS-23, the regulation of the Korean government for the light airplane type certification.