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.

블럭탐색 제어를 이용한 프랙탈 영상 부호화 시간 향상과 컬러 영상에의 응용

박철우,정동웅,김태형,김두영 東亞大學校 附設 情報通信硏究所 1996 情報通信硏究所論文誌 Vol.4 No.1

In this paper, in order to reduce block search area during the process to determine the coefficient of IFS transform equation in Fractal Coding, We performed the following steps : First, We partitioned Domain blocks and Range blocks with certain critical point determined by the edge characteristcs and the direction of brightness. When similar block's detected, the Domain block in the same class of the given range was only searched. Second, When the processing is on, We determined the linear list structure with the second error limit, We, therefore, could control coding time, We tryed to improve the compression rate of the Image with reducing the number of times of tranformation by changing the area of block with Quadtree Partitioning, and also tried to progress the fidelity of the image by changing the search density of search area, according to the magnitude of range block. We applied these method to image compression of 24-bpp color. First of all, after converting the RGB coordinate into YIQ Coordinate which has brightness signal and chrominance signal, We minimized by a quarter and coded I,Q signal which implies the information of the color but takes just small part at image information and on the case of decoding, with linear interpolation method we got I,Q signal enlarged as it was. All throughout these processing, We could find out that There are no damages on the original image, and we are able to make better result on compression rate and fidelity of image comparing with those of conventional Fractal Coding method which was applied to the RGB images.

능동소나에서 다중경로환경을 고려한 표적의 도플러 탐지

이수형,이철목,박상배,이평기 위덕대학교 산업기술연구소 2000 산업기술연구소 논문집 Vol.4 No.1

최근 능동 소나에서는 표적의 탐지 성능을 향상시키기 위하여 "높은 시간-대역폭곱"의 파형들을 사용한다. 표적까지의 거리와 표적의 속도를 추정하는 방법으로 FFT-기반 상관관계 기법이 많이 사용되고 있으나, 다중경로 환경에서는 운용자의 요구를 만족하기에 충분한 결과를 나타내지 못하고 있다. 본 논문에서는 다중경로 환경에서 직접경로 신호의 도플러 변이와 도달시간의 탐지 정확도를 높이기 위한 새로운 기법을 제안하였다. In modern active sonar, so-called "high time-bandwidth product" waveforms are used to obtain processing gain for improved detection performance. FFT-based correlation processing is used to detect doppler shift for velocity of target and arrival time, but obtained results are not enough to satisfy the operational needs in multipath environment. In this paper, the new algorithm is proposed in order to improve detection accuracy of doppler shift and arriving time of direct path in multipath environment. It is achieved since the replica is made with considering multipath.

3차원 근거리 표적의 효과적인 위치 추정 알고리듬

이철목,이수형,박상배 위덕대학교 산업기술연구소 2000 산업기술연구소 논문집 Vol.4 No.1

본 논문에서는 다중 3차원 근거리표적의 위치를 효과적으로 추정하는 기법을 제안하였다. 제안한 기법은 세 개의 부분센서배열을 이용하여 기존의 3D MUSIC에서의 3차원 탐색을 3번의 1차원 탐색으로 대치함으로써 연 산량을 감소시켰다. 각각의 부분센서배열에서 얻은 센서신호로부터 표적이 원거리에 있다고 가정하고 원거리 입체각을 추정하면 추정된 입체각은 실제 근거리 표적의 위치인 방위각, 고각, 거리의 함수로 주어진다. 그러므로 세 개의 부분센서배열로부터 얻은 세 개의 함수를 연립하여 풀면 실제 근거리표적의 위치를 추정할 수 있다. 또 한 다중 표적의 경우, 추정치에 대하여 3차원 MUSIC 스펙트럼값을 비교함으로써 연관 문제를 해결하였다. In this paper, we are proposing an efficient 3D source localization algorithm using 3 uniform linear subarrays. The proposed algorithm replaces 3D search required in conventional 3D MUSIC algorithm with 3 1D searches, and thus reduces computational burden. The estimate of the 1D conic angle obtained from a subarray under the far-field assumption satisfies a nonlinear algebraic equation of the true source bearing angle, elevation angle, and range. The proposed algorithm estimates source location by solving 3 algebraic equations obtained from 3 subarrays. Comparing 3D MUSIC spectrums of the estimated source locations, the proposed algorithm solves pairing problem for multiple sources localization.

잔향 환경에서 표적탐지 성능향상을 위한 능동소나 음원 형성기법 연구

이철목,박도현,이수형 위덕대학교 산업기술연구소 2001 산업기술연구소 논문집 Vol.5 No.1

천해에서 능동소나 운용시 잔향에 의해 표적탐지 성능이 심각한 영향을 받게 되므로 잔향의 영향을 최소화하기 위한 음원 형성기법에 대한 연구가 활발히 진행되고 있다. PTFM(Pulse Train Frequency Modulation) 신호는 CW 신호의 도플러 제거 특성과 LFM 신호의 넓은 대역폭 특성을 이용하여 잔향의 영향을 최소화하기 위해 고안된 펄스이다. 본 논문에서는 펄스의 종류에 따른 탐지성능을 분석할 수 있는 음향모델을 이용한 성능분석모데를 이용한 성능분석모델을 구현하였으며, 이를 이용하여 일반적인 능동소나의 송신신호와 PTFM 신호의 잔향제한 환경에서의 탐지성능을 분석하였다.

스포츠 활동 참여가 생산직 근로자의 직무만족에 미치는 영향

노형철,정용준,윤오남,박형태,김승동 조선대학교 스포츠과학연구소 2000 스포츠科學硏究 Vol.11 No.-

The purpose of this study was to examine effects of Sport activity Participation of Production Laborers on Job Satisfaction. 380 subjects who had lived in five major cities answered questionnaires. The results were as follows. 1. In proportion of participants to non-participants in sport and leasure activities, the proportion of participants was higher. The most frequently replied answer to the question that how many years have you participated in sport and leasure activities was 3 years. The highest frequency in participation during week-days was 2 3 times. 2. In comparison of personal characteristics of the labores with proportion of participation in sport and leasure activities, sex and marital status were significantly related to participation in the activities. Proportion of continuous participation in sports and leasure activities was higher in males while proportion of participation in the acti vities was higher in females than in males. Age, formal schooling, monthly income and types of job were not significantly related to participation in sport and leasure activities. 3. In comparison of personal characteristics of the labores with job satisfaction, job satisfaction was higher in participants in sport and leasure activities than in non-participants.

혈관 반응성에 대한 Cyclooxygenase 억제제 효과와 Cyclooxygenase 발현 변화

이기영,박진우,엄은아,강영진,이광윤,최형철 영남대학교 의과대학 2006 Yeungnam University Journal of Medicine Vol.23 No.1

진통과 해열작용을 가진 NSAIDs는 소화기계에 대한 부작용 때문에 COX-2 선택성 억제제로 대체되고 있다. 그러나 COX-2 선택적 억제제는 심혈관계에 대한 부작용이 보고되고 있어 혈관 평활근에 대한 직접적인 연구가 필요하다. 이에 본 연구에서는 혈관 반응성에 미치는 celecoxib와 aspirin, indomethacin의 영향을 비교 분석하였다. 또한 COX-1, COX-2 단백질 발현에 대한 indomethacin과 NO 공여제의 영향을 조사하였다. Phenylephrine 유발 수축반응에서 전처치 된 celecoxib, indometacin, aspirin 순서로 혈관 반응성을 증가시켜, cyclooxygenase를 억제하면 혈관 수축성물질에 대한 반응성이 커질 수 있음을 나타낸다. 이중 cyclooxygenase에 대해 비가역적으로 강한 억제를 나타내는 aspirin이 제일 강한 효과를 나타내어 여기에 대한 연구는 더 필요할 것으로 생각된다. 혈관평활근 세포의 COX-2 단백질 발현은 indomethacin과 SNP, NOR-3 처치에 의해 증가되었으며, LPS를 이용하여 혈관염증을 유발시키는 경우 혈관평활근 세포의 COX-2 단백질 발현이 증가되었고, 이 상태에서 SNP 100μM 전처치로 COX-2 단백질 발현을 감소되었으며, NOR-3 100 μM은 COX-2 단백질 발현을 증가시켰다. LPS 유도 nitrite 생성에서 NOR-3는 SNP 보다 더 많은 nitrite를 생성시켰다. 이는 혈관의 수축반응에서 aspirin은 강한 상승작용을 유발하고, 혈관평활근 세포의 COX-2 발현은 NO 공여제, 혈관염증 유무에 따라 차이가 있는 것을 나타낸다. Background: There is controversy regarding whether COX-2 specific inhibitors are associated with elevation of blood pressure. We compared the effects of aspirin, indomethacin, and celecoxib for vascular reactivity induced by phenylephrine. We also tested the effects of indomethacin and NO donor on COX-1 and COX-2 protein expression, as well as nitrite production in culture medium of vascular smooth muscle cells. Materials and Methods: In this experiment, we used the isometric tension study for vascular reactivity. After 45 minutes of pretreatment with aspirin, indomethacin, celecoxib, and phenylephrine induced contractions were tested. COX-1 and COX-2 protein expressions were analyzed by Western blot and nitrite production by the Griess reaction. Results: Although celecoxib pretreatment caused enhanced arterial contraction, aspirin pretreatment induced more potent arterial contraction than celecoxib in the isometric tension study of rabbit femoral artery. COX-1 protein expression was unchanged by indomethacin, SNP and NOR-3; COX-2 protein expression was increased by the addition of indomethacin, SNP, and NOR-3. Especially, NOR-3, a NO donor, significantly increased COX-2 protein expression with unstimulated conditions as well as LPS stimulation. Induction of nitrite production was higher with NOR-3 treatment than SNP treatment with LPS stimulation. Conclusion: These results suggest that aspirin caused more potent vascular contraction than celecoxib and indomethacin. COX-2 expression in VSMC depended on the types of NO donor and LPS stimulation.

징병 신체검사에서 나타난 청소년기 추간반탈출증의 유병률과 임상적 특징 : A Study Based on Examinations for Conscription

홍창기,박철기,박형천,윤승환 대한척추신경외과학회 2004 Neurospine Vol.1 No.1

Objective: The authors analyzed the large series of intervertebral disc herniation in adolescence to evaluate the prevalence, clinical characteristics, and possible risk factors on the basis of the data from the examinations for conscription. Material and Methods: Of 77685 nineteen-old-males who were given an examination for conscription at Regional Military Manpower Administration of Seoul in 2002, 382 patients exempted from conscription due to intervertebral disc herniation were analyzed. The diagnosis were made from the medical certificate, medical record, magnetic resonance imaging(MRI)(or computed tomography(CT)) which examinee presented and confirmed with the aid of reexamination of CT. Radiological char cteristics and severity of intervertebral disc herniation as well as structural abnormalities of vertebral columns were carefully evaluated with CT scan and MRI scan. Possible risk factors like overweight, structural abnormality of vertebral column, trauma were analyzed statistically using one-sample T-test and chi - square test on the assumption that P value less than 0.05 was considered statistically significant. Result: Prevalence of intervertebral disc herniation in adolescence aged nineteen years and younger were 0.5%. L4-5 level was the most frequently affected site followed by L5-S1. Of all 382 patients of intervertebral disc herniation, 29% were considered serious with reference to radiological evidence of root compression or siginificant discogenic spinal stenosis. Limbus fracture was found in 6.8% of patients. Overweight was the significant risk factor of the disease(p=0.0). However, neither structural abnormality of vertebral column nor trauma showed any relation to pathogenesis of intervertebral disc herniation. Conclusion: In adolescence aged nineteen years and younger, the prevalence of intervertebral disc herniation was 0.5% and accompanying limbus fracture was more frequent when compared with adult. Overweight was the only significant risk factor of the disease.

탄화물 입자 강화 7075 Al 합금 기지 복합재료의 미끄럼마멸 특성 연구

강석하,박형철,강신철,김용석 국민대학교 생산기술연구소 2002 공학기술논문집 Vol.25 No.-

Effects of the type and volume fraction of carbide-particle-reinforcements on dry sliding wear behavior of 7075 Al alloy matrix composites were investigated. SiC, TiC and B₄C reinforced 7075 Al alloy matrix composites were manufactured by a pressureless infiltration technique and wear tested. Wear tests were carried out using a pin-on-disk wear tester with varying loads of 3N-160N at a constant sliding velocity of 0.2m/s. AISI 52100 bearing steel ball was a counterpart of the composites. Wear resistance of the composites was always higher than that of the monolithic alloy except the TiC reinforced 7075 Al matrix composite. The resistance increased with the increase of volume fraction of the reinforcing particles. Among the composites, the TiC reinforced composite had the lowest wear resistance and the B4C reinforced composite showed the highest wear resistance.

신경독성 물질에 폭로되지 않은 건강한 남자의 신경행동학적 검사 수행능력

이세훈,김형아,이원철,장성실,이경재,박정일,정치경 大韓産業醫學會 1995 대한직업환경의학회지 Vol.7 No.1

Five items among neurobehavioral core test battery of World Health Organization, including Santa Ana dexterity, pursuit aiming, digit symbol, simple reaction time, and Benton visual retention, were administered to the workers occupationally non-exposed to neurotoxic agents by operational guide for the WHO neurobehavioral core test battery. Subjects were volunteers from the industrial workers(117) and clerks(40). Detailed occupational history such as exposed agents including noise or vibration, educational level, residence, smoking and drinking habit were recorded. Most of the neurobehavioral tests were correlated with age and educational level. Smoking was correlated with pursuit aiming and digit symbol. Vibration affected pursuit aiming. Job type(industrial workers vs. clerks) and noise exposure did not affected among tested items. Multiple regression analysis was done for establishing predict equation to estimate normal ranges of the tests for male workers. Age was shown to be main independent variable affected for all tests except wrong dot of pursuit aiming. Educational level was also shown to affected most of the tests except Santa ana dexterity and wrong dot of pursuit aiming. Alcohol consumption affected Santa Ana dexterity, non-preferred hand, and smoking affected only wrong dot of pursuit aiming after multiple regression analysis.