한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

백색부후균 전처리에 의한 목재 칩의 Biopulping

강규영,김형진,양봉숙,조병묵,오정수 동국대학교 생명자원과학대학 연습림 2000 연습림논문집 Vol.- No.6

Pulping process is to mainly obtain lignocellulosic fibers for papermaking from wood resources. Three types of pulping method have been basically employed, such as chemical pulping, mechanical pulping, and their combination methods. Biopulping technique has been mainly applied in mechanical pulping by pretreatment of white-rot fungi into the ultrastructure of wood cell wall. The main purpose of biopulping is to improve the pulp qualities, paper properties, and to reduce the energy costs and environmental impact, compared to traditional pulping systems. Nowadays, biopulping is frequently tried in chemical pulping operation for environmental concept, fiber modification, improvement of physical properties of paper and economic savings. The pretreatment of white-rot fungi prior to chemical pulping could affect the swelling and softening of wood cell walls by the behaviors of modification and depolymerization of ligin compounds. This study was carried out to investigate the effectiveness of biological treatment to wood chips by white-rot fungus and its structural change of lignocellulosic fiber via kraft pulping. A rotary bioreactor was applied for pretreatment of biological action. The treatment of white-rot fungus was shown in weight loss of chips. After bio-kraft pulping, kappa number and total yield of pulps were measured, and reduced. Freeness(CSF) values were also decreased. Whereas brightness values were increased, compared to untreated control. The physical strength of handsheets was shown a slight increase in tensile, tear, burst, and folding endurance, with bio-treatments.

비글개에서 분만 후 자궁수복의 연속적 초음파상

손형원, 김홍석, 김형진, 김일화, 이기창, 이청산, 강현구 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

본문참고

로봇 매니퓰레이터의 선형모델을 이용한 다변수 제어기 설계

이준형,김정주,강진식 濟州大學校工科大學産業技術硏究所 1999 尖端技術硏究所論文集 Vol.10 No.1

In this paper, we present a multivariable controller for the robot manipulator. By using the linearized model, calculation time is reduced because of the linearized model could relax the nonlinear property. Since the linearized model improve the influence of the modification of the robot dynamic parameters, errors, caused by the variation of dynamics such as the unknown load of a manipulator, nonlinear properties are compensated. By this reason, The presented controller can be adopted in the industrial application. An usual multivariable controller, using pole placement, has relatively a large tracking errors. In order to obtain small tracking errors, rapid response, and stabilize the robot manipulator, the linearized dynamics of the manipulator and PID controller structure are used in the presented controller which is designed via pole placement algorism. To show the suggested controller have rapid trajectory tracking property, and it is not affected by the unknown load and load variation, the simulation results of the 2-link robot manipulator are presented.

로봇 매니퓰레이터의 선형모델을 이용한 다변수 제어기 설계

이준형,김정주,강진식 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.1

In this paper, we present a multivariable controller for the robot manipulator. By using the linearized model, calculation time is reduced because of the linearized model could relax the nonlinear property. Since the linearized model improve the influence of the modification of the robot dynamic parameters, errors, caused by the variation of dynamics such as the unknown load of a manipulator, nonlinear properties are compensated. By this reason, the presented controller can be adopted in the industrial application. An usual multivariable controller, using pole placement, has relatively a large tracking errors. In order to obtain small tracking errors, rapid response, and stabilize the robot manipulator, the linearized dynamics of the manipulator and PID controller structure are used in the presented controller which is designed via pole placement algorism. To show the suggested controller have rapid trajectory tracking property, and it is not affected by the unknown load and load variation, the simulation results of the 2-link robot manipulator are presented.

개방형 원심압축기에서의 틈새크기에 따른 유동특성에 관한 실험적 연구

김진형,조강래 연세대학교 산업기술연구소 1994 논문집 Vol.26 No.2

The Pressure loss due to leakage flow is directly related to the tip clearance size of centrifugal impeller. The performance and the pressure distribution along the shroud casing are measured by using pressure transducer system for unshrouded centrifugal compressor at different size of tip clearance. The characteristic curves With respect to the size of tip clearance are presented as one curve regardless of rotational speed. As the size of tip clearance increases form 0.5mm through 2.0 mm, the values of pressure coefficient of characteristic curves decrease linearly due to the increase of leakage loss. The reduction rate of static pressure coefficients per 1 mm tip clearance is 0.04∼0.047, and the reduction rate per c/b₂is 0.28 evenly. The pressure coefficient for radial direction on the shround casing surface is presented as one curve regardless of rotational speed and decreases linearly. The reduction rate of pressure coefficient is nearly identical to that of characteristic curves.

셀레콕시브 및 그 합성유도체들의 항암활성 스크리닝

박정란,강진형,구효정,노지영,류형철,박상욱,고동현,조일환,이주영,황다니엘,김인경 한국약제학회 2003 Journal of Pharmaceutical Investigation Vol.33 No.2

Selective COX (cyclooxygenase)-2 inhibitors including celecoxib have been shown to induce apoptosis and cell cycle changes in various tumor cells. New inhibitors are recently being developed as chemomodulating agents. We evaluated celecoxib and screened 150 synthetic compounds for anti-proliferative activities in vitro. Effects of celecoxib on COX activity, cell growth, cell cycle distribution, and apoptosis induction were determined in A549 COX-2 overexpressing human non-small cell lung cancer (NSCLC) cells. The COX inhibition of celecoxib increased with concentration up to 82% at 1μM after 24 hr exposure. Forty μM and 50μM of celecoxib induce G_1 arrest, and TUNEL-positive apoptotic cells, respectively. Among 150 compounds, several compounds were selected for having greater COX-2 inhibitory activity and higher selectivity than celecoxib with growth inhibitory activity. Celecoxib showed concentration-dependent COX inhibitory activity, and ability to induce cell cycle arrest and apoptosis in human NSCLC cells in vitro. Among synthetic analogues screened, several compounds showed promising in vitro activity as COX-2 inhibitory anticancer agents, which warrant further evaluation in vitro and in vivo.

Descriptor 시스템 모델링 밍 극배치 제어기 설계

김정주,이준형,강진식 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.1

Many of the engineering systems such a s electrical circuits. communication networks. power systems, aerospace systems and singular systems can be modelled by a descriptor system which is similar to the state space representation of the system. In this paper, we present a control algorithm for the descriptor system by using eigenstructxe assignment. When the number of poles of the system changed due to the parameters variation, the system can be modelled by two subsystems a s the one is static system and the other is dynamic. And two systems are connected serially by the manner that the one system output is connected to the input of the other system. The controller presented in this paper, designed by eigenstructure assignment, can treats such a singular system easily. To show the suggested controller has a good feature, we apply the presenied controller to the inverted pendulum system.

Descriptor 시스템 모델링 및 극배치 제어기 설계

김정주,이준형,강진식 濟州大學校工科大學産業技術硏究所 1999 尖端技術硏究所論文集 Vol.10 No.1

Many of the engineering systems such as electrical circuits, communication networks, power systems, aerospace systems and singular systems can be modelled by a descriptor system which is similar to the state space representation of the system. In this paper, we present a control algorithm for the descriptor system by using eigenstructare assignment. When the number of poles of the system changed due to the parameters variation, the system can be modelled by two subsystems as the one is static system and the other is dynamic. And two systems are connected serially by the manner that the one system output is connected to the input of the other system. The controller presented in this paper, designed by eigenstructure assignment, can treats such a singular system easily. To show the suggested controller has a good feature, we apply the presented controller to the inverted pendulum system.

흰쥐 생체시료 중 5-플루오로우라실 및 테가푸르의 안정성

장지현,박종국,강진형,정석재,심창구,구효정 한국약제학회 2004 Journal of Pharmaceutical Investigation Vol.34 No.3

5-Fluorouracil (5-FU) is an antimetabolite anticancer agent active against many types of solid tumors. Tegafur (TF), a prodrug of 5-FU, is frequently used in combination with uracil as dihydropyrimidine dehydrogenase (DPD) inhibitory fluoropyrimidine. We studied the stability of 5-FU and TF in biological fluids of rats and determined their bioavailability (BA) and excretion into bile, and urine. The drug concentrations were analyzed by an HPLC method. At room temperature, there was a 14-30% decrease in the concentration of 5-FU and TF in bile, urine, and plasma specimen at 10 and 100 μg/ml over 240 min. No significant difference was noted among the sample types or between two different concentrations of 10 and 100 μg/ml. The decrease in drug concentration was significantly less in samples kept on ice (6-12%) for both drugs. These data indicate that biological fluid samples containing 5-FU or TF in plasma, urine, or bile should be placed on ice during the sample collection. Following these storage guidelines, samples were collected after administration 50 ㎎/㎏ of each drug via i.v. or oral route. BA was 1.5 folds greater for TF (60%) than that of 5-FU (42%). Approximately 0.52 and 3.3% of the i.v. doses of 5-FU and TF was excreted into bile, respectively. Renal clearance of 5-FU was about 16% of its total body clearance. These results suggest that instability of 5-FU and TF in biological fluids should be considered in pharmacokinetic or pharmacogenomic studies.