• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.51-59
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• 2021

Objective : Several studies have reported inconsistent findings among countries on whether off-hour hospital presentation is associated with worse outcome in patients with acute stroke. However, its association is yet not clear and has not been thoroughly studied in Korea. We assessed nationwide administrative data to verify off-hour effect in different subtypes of acute stroke in Korea. Methods : We respectively analyzed the nationwide administrative data of National Emergency Department Information System in Korea; 7144 of ischemic stroke (IS), 2424 of intracerebral hemorrhage (ICH), and 1482 of subarachnoid hemorrhage (SAH), respectively. "Off-hour hospital presentation" was defined as weekends, holidays, and any times except 8:00 AM to 6:00 PM on weekdays. The primary outcome measure was in-hospital mortality in different subtypes of acute stroke. We adjusted for covariates to influence the primary outcome using binary logistic regression model and Cox's proportional hazard model. Results : In subjects with IS, off-hour hospital presentation was associated with unfavorable outcome (24.6% off hours vs. 20.9% working hours, p<0.001) and in-hospital mortality (5.3% off hours vs. 3.9% working hours, p=0.004), even after adjustment for compounding variables (hazard ratio [HR], 1.244; 95% confidence interval [CI], 1.106-1.400; HR, 1.402; 95% CI, 1.124-1.747, respectively). Off-hours had significantly more elderly ≥65 years (35.4% off hours vs. 32.1% working hours, p=0.029) and significantly more frequent intensive care unit admission (32.5% off hours vs. 29.9% working hours, p=0.017) than working hours. However, off-hour hospital presentation was not related to poor short-term outcome in subjects with ICH and SAH. Conclusion : This study indicates that off-hour hospital presentation may lead to poor short-term morbidity and mortality in patients with IS, but not in patients with ICH and SAH in Korea. Excessive death seems to be ascribed to old age or the higher severity of medical conditions apart from that of stroke during off hours.

• 한국기계가공학회지
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• 제14권6호
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• pp.49-56
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• 2015

For designing working devices of construction equipment, it is necessary to consider not only sufficient working ability but also available working range. Therefore, it is important to select the appropriate pivot positions of links. This paper presents a study on selection of pivot points of links used in construction equipment. To analyze the effect of each pivot point, a design program for pivot selection is developed. A conventional pivot design method requires a complicated process because it needs to create a certain working position manually to evaluate its performance. However, the developed program includes an automatic link assembly algorithm; thus, the working device can easily be analyzed by using pivot information of links. The developed program also included a kinematic/static analysis module and characteristic analysis algorithms. Therefore, it is possible to easily analyze a working device model created through the automatic assembly algorithm, whereby users can easily analyze the effect of each link pivot point for the actual product design.

• 대한인간공학회지
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• 제30권5호
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• pp.671-681
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• 2011

Objective: The purpose of this study is to compare the workload level at each lower limbs posture and suggest the ergonomic workstation guideline for working period by evaluating the imbalanced lower limbs postures from the physiological and psychophysical points of view. Background: Many workers like welders are working in various imbalanced lower limbs postures either due to the narrow working conditions or other environmental conditions. Method: Ten male subjects participated in this experiment. Subjects were asked to maintain 3 different lower limbs postures(standing, squatting and bending) with 3 different working conditions(balanced floor with no scaffold, imbalanced floor with 10cm height of scaffold, and imbalanced floor with 20cm height of scaffold). EMG data for the 4 muscle groups(Retus Femoris, Vastus Lateralis, Tibialis Anterior, Gastrocnemius) from each lower limbs posture were collected for 20 seconds every 2 minutes during the 8 minutes sustaining task. Subjects were also asked to report their discomfort ratings of body parts such as waist, upper legs, lower legs, and ankle. Results: The ANOVA results showed that the EMG root mean square(RMS) values and the discomfort ratings(CR-10 Rating Scale) were significantly affected by lower limbs postures and working time(p<0.05). The correlation was analyzed between the EMG data and the discomfort ratings. Also, prediction models for the discomfort rating for each posture were developed using physical condition, working time, and scaffold height. Conclusion: We strongly recommend that one should not work more than 6 minutes in a standing or squatting postures and should not work more than 4 minutes in a bending posture. Application: The results of this study could be used to design and assess working environments and methods. Furthermore, these results could be used to suggest ergonomic guidelines for the lower limbs postures such as squatting and bending in the working fields in order to prevent fatigue and pain in the lower limbs body.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.214-218
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• 1988

This paper suggests mathemathical engine model which can simulate generalized gasoline engine. Suggested engine model contains air/fuel inlet element, intake manifold, combustion, engine dynamics. In order to analyze a gasoline engine, physical characteristics of engine and steady state engine data should be controlled. In adaptation for abrupt change of circumstance or drive conditions, this model can analyze important physical phenomena in the intake manifold by computer simulation. This model can also evaluate statuses of drive under various working conditions precisely. Therfore, this model suggests basic datum to evaluate the engine system which are needed in designing and development of engine controller.

• 응용통계연구
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• 제27권7호
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• pp.1243-1255
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• 2014

본 연구에서는 업종에 따른 다양한 근로환경 요인들을 파악하고 관련 분야의 산업안전보건 정책을 판단할 수 있도록 근로환경조사 기초자료를 분석하여 사회요인을 고려한 지수 및 지표 개발을 목표로 하였다. 지표개발을 위해 OECD에서 제시하는 지표개발 가이드라인과 해외의 지표개발 사례들을 벤치마킹하여 수행되었다. OECD의 압력-상태-대응 모형을 벤치마킹하여 건강과 관련 있는 지표들을 제시하였다. 근로환경조사의 압력-상태 건강관련 지표는 압력은 물리적 위험환경, 노동시간, 업무환경, 사회 환경으로 구성되었고, 이에 따른 상태 항목은 건강관련 항목으로 정신건강, 신체건강, 건강문제로 인한 결근, 업무 만족으로 구성되었다. 그 결과 임금근로자, 상용근로자, 관리자, 사무종사자, 전문가 및 관련 종사자, 50세 미만 근로자의 압력-상태 지표가 상대적으로 양호하였다. 반대로, 50세 이상, 자영업자, 일용 직, 농림어업 숙련직, 단순노무, 장치 기계 조립 근로자의 압력-상태 지표가 상대적으로 취약한 것으로 나타났다.

• 한국전자거래학회지
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• 제18권2호
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• pp.257-277
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• 2013

경영정보시스템 분야 및 DeLone and McLean의 정보시스템 성공모형 등에 관한 연구들은 기업 등의 정보시스템 도입 및 이용을 통해 이용자 개인 및 기업 등의 성과에 영향을 미칠 수 있도록 관련 요소가 개발 운영되어야 함을 제시하고 있다. 본 연구의 목적은 콜센터 고객정보 시스템의 이용자 만족도에 영향을 미치는 요인을 탐구함에 있다. 근무환경 및 직무 만족에 관한 선행 연구와 수정된 DeLone and McLean의 정보시스템 성공모형을 이용한 구조방정식 모형을 설정하여 콜센터 상담사원 539명을 대상으로 설문조사를 실시하였다. 본 연구의 결과는 다음과 같다. 첫째, 정보시스템의 세 가지 품질이 근무환경, 직무만족, 이용자 만족도에 영향을 미치는 11개 가설 중 7개 가설이 채택되었으며 둘째, 근무환경은 시스템 품질 및 정보 품질과 이용자 만족도간 부분매개를, 서비스 품질은 완전매개 효과가 있음을 확인하였다. 시사점으로는 향후 정보시스템의 운영 성과가 제고될 수 있도록 이용자의 좋은 근무환경 구축 및 개선이 필요함을 제시하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2000년도 제14회 학술강연논문집
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• pp.8-8
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• 2000

In this paper are presented main power and gasdynamic characteristics of C-l6VK hypersonic test cell of Research Test Center of CIAM. Gasdynamic adjustment of the C-l6VK test cell was carried out with the working section constructed on scheme of Ramjet/scramjet test in free stream. Gasdynamic adjustment was conducted stage by stage in tile following sequence. First, check and preparation of all technical systems and checking measuring system. Than determination of the characteristics of test cell on cold (without the heating of air at entrance) regime and determination of the characteristics of test cell on regimes with the heating of air. Finally determination of tile characteristics of test cell with the loading of the working part by object. On tile final stage of gasdynamic adjustment two experiments with tile axisymmetric Scramjet model loaded into the working part of test cell were conducted. The first experiment was conducted with the purpose of determination of flow parameters with the object leaded into the working part and verification of experiment cyclogram. The second experiment was conducted with injection of hydrogen into the combustion chamber of object, that is tile conditions on test cell simulated Scramjet flight Mach number M = 6. Such methodology of gasdynamic adjustment allows to determine influence of experimental object on flow parameters in the working part at different conditions of experiment (with the burning in combustion chamber of object and without the homing), and also to compare flow characteristics in the object duct.

• 한국학교ㆍ지역보건교육학회지
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• 제17권1호
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• pp.59-73
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• 2016

Objectives: The working environment affects employees' physical and mental aspects, and has a deep associations with depression. The purposes of this study are to investigate how hazardous environment working experience impacts on depression, to provide rationale and practical implications for reducing depression and drinking. Methods: This study targeted 215 dental hygiene students from 3 universities located in Gyeonggi-do from November 30 to December 4, 2015. We analyzed the data with frequency analysis, descriptive statistics, t-test. One-way ANOVA, Pearson correlation coefficient, Regression analysis by using SPSS. Results: This study showed that experience working in hazardous environments increased depression and alcohol drinking, on the other hand alcohol drinking reduced depression. In addition, experience working in hazardous environments effected on depression indirectly through mediating of drinking, subjective health had not role of Moderating Effects between experience working in hazardous environments and depression. Conclusions: In order to reduce workers' depression and alcohol, the improvements of harmful environment are needed. For this governments and local governments should efforts to support enhancing workplace environment, to develop model of standard work environment, and to change employers' awareness on the harmful environment.

• 한국생활과학회지
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• 제21권5호
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• pp.863-874
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• 2012

This study examined the factors affecting the number of hours spent in child care centers by children of dual-working families. Data for this study was collected by way of a survey that involved a total of 33 child care centers. A total of 465 families took part in the study. Child factors, parental factors, household factors, and child care center factors were included in the hierarchical regression model on which this study was based. The results of this study identified eight primary factors related to the number of hours spent in child care centers by children of dual working families, which were as follows: (1) children's engagement in extracurricular activities, (2) maternal working hours, (3) parents' preference for child care center as a non-parental care provider, (4) the number of children attending the child care center in the household, (5) the presence of adults other than parents in the household, (6) accessibility to the child care center, (7) the satisfaction with child care services, and (8) the primary purpose of child care center use.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1303-1309
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• 2003

This paper presents the static and dynamic measurements for the strength and motion characteristics as well as the improved procedures to assess strength of wheel loaders. Two scenarios for static measurement were decided by which cylinder was actuating. The dynamic measurement was performed for two types of motion, that is, simple reciprocation of the working devices and actual working motion including traveling, digging and dumping. The measured items were stresses, cylinder pressures and strokes. Stress induced by bucket working showed higher level than that by boom working. The measured cylinder speeds were relatively superior to the design speeds. Working stress histories were thought to be closer to static rather than dynamic. A fully assembled FE model was prepared for structural analysis. In this paper, a more simple method was suggested to avoid nonlinearity caused by heave of rear frame under digging forces. Also how brake affected on structural behavior and digging force was examined closely in relation with tire pressure. It was confirmed that the overall stress level of wheel loader during turning traveling with loaded bucket was far lower than the yield stress of material.