• Safety and Health at Work
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• v.10 no.1
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• pp.30-38
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• 2019

Background: Police officers' stress perception, frequency of stressful events (stressors), and police work characteristics may contribute to poor sleep quality through different mechanisms. Methods: We investigated associations of stress severity (measured by stress rating score) and frequency of stressors with sleep quality and examined the influence of police work characteristics including workload, police rank, prior military experience, and shift work on the associations. Participants were 356 police officers (256 men and 100 women) enrolled in the Buffalo Cardio-Metabolic Occupational Police Stress Study from 2004 to 2009. A mean stress rating score and mean frequency of stressors occurring in the past month were computed for each participant from the Spielberger Police Stress Survey data. Sleep quality was assessed using the global score derived from the Pittsburgh Sleep Quality Index survey. Linear associations of the stress rating score and frequency of stressors with sleep quality (Pittsburgh Sleep Quality Index global score) were tested. Age, sex, race/ethnicity, and smoking status were selected as potential confounders. Results: The stress rating score was positively and independently associated with poor sleep quality (${\beta}=0.17$, p = 0.002). Only workload significantly modified this association (${\beta}=0.23$, p = 0.001 for high workload group; p-interaction = 0.109). The frequency of stressors was positively and independently associated with poor sleep quality (${\beta}=0.13$, p = 0.025). Only police rank significantly modified the association (${\beta}=0.007$, p = 0.004 for detectives/other executives; p-interaction = 0.076). Conclusion: Both police officers' perception of stress severity and the frequency of stressors are associated with poor sleep quality. Stress coping or sleep promotion regimens may be more beneficial among police officers reporting high workloads.

• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.127-133
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• 2007

The purpose of this study is to apply WDA (Work Domain Analysis) for the development of EID (Ecological Interface Design) of vehicle control display. At first, a work domain model on the automobile operation was developed using the AH (Abstraction Hierarchy) which is one of WDA tools. Secondly, information requirements that should be included in vehicle control displays were extracted on the basis of the completed model. The vehicle control information that typical automobiles interface displays currently provide occurred on the low level of the work domain model. This implies that current control displays impose too heavy cognitive workload on automobile drivers. Information requirements that can be included new vehicle control display are also discovered in the high level of the work domain model. The detailed information for EID was not proposed in this study. In the further study, the development of vehicle control display will be deeply conducted, using the results of this study.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.1
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• pp.105-115
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• 2009

Background: The resource-based relative value scale has been applied to Korean medicine services as part of the National Health Insurance, yet the proper scoring method for physician's work needs to be developed. Objectives: To measure physician's work for Korean medicine services using Analytical Hierarchy Process(AHP) and to compare results abstracted by AHP with those by Magnitude Estimation method. Methods: We developed the AHP questionnaires for Korean Medicine services and administered it to 12 Korean medicine insurance experts. Weighted scores were calculated and were converted into physician's work scores. Results: In AHP measurement, the physician's work scores for acupuncture activities, especially special acupunctures, far increased, while those for diagnosis and basic consultations decreased. Variations in the scores enlarged. Conclusions: As an alternative, AHP method can be considered for measuring the physician's work for Korean medicine services with careful management of scoring variation.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.159-164
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• 2005

In this paper, we study some problems of the scheduling on the fixed area in a shipbuilding. The scheduling, constrainted a working area, is not easy to make a load balance and to operate a change of daily work plan. we proposed a block arrangement algorithm to make the load balance and developed a system used to operate the change of daily work plan.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.360-363
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• 2004

This review is concerned with the MP (multipactor) phenomena of the diplexer for RFDU DM of next generation satellite. The MP discharge is serious problems to design RF components in space applications such ase damage of physical structure, performance degradation, and mission failure of the satellite. In this work, we employed the 3D finite element method (FEM) to calculate the critical gap points and adopted ESTEC curve, MP susceptibility zone, to analyze the maximum handling RF power in the diplexer. And this work also recommends that one should design the tx filter of the diplexer which is more wider bandwidth upto the points to escape the ears of the group delay especially the cavity type of RF components in space applications.

• Journal of Family Resource Management and Policy Review
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• v.17 no.2
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• pp.19-35
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• 2013

The purpose of this study is to analyze the effective factors that influence subjective cognition, conflict degree of work-family balance, and cognition of family strength according to general characteristic factors, working environmental factors, and home environmental factors, as well as analyze the relationships among subjective cognition, conflict degree, and cognition of family strength. The main data source for analysis in this study is the Second National Survey of Korean Families by the Ministry of Gender Equality and Family in 2010. The survey includes the analysis of 419 respondents who have a dual income and live with their wife. The collected data are analyzed using SPSS 19.0. The results of the study are as follows. First, subjective cognition of work-family balance is influenced by satisfaction of work, division of housework, and care of family. Second, the conflict degree of work-family balance is influenced by age, working week, and satisfaction with work. Third, the relationship between subjective cognition and conflict degree of work-family balance is a negative correlation. The relationship between subjective cognition of work-family balance and cognition of family strength is a positive correlation but the difference between conflict degree of work-family balance and cognition of family strength is not significant. Finally, for the married men, the working environmental factor is a significant factor for the work-family balance. And the higher the satisfaction of work and division of domestic work, the greater is the balance between work and family. This suggests that they also have a higher cognition of family strength.

• International Journal of Human Ecology
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• v.6 no.2
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• pp.37-49
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• 2005

This paper gives special attention to the changes of time use patterns of the German population for eating and drinking as well as for household work. It especially examines the changes in time use for meals eaten at home and away from home as well as the division of labour for nutrition provision activities between men and women. The presented results originated from two time budget surveys conducted in Germany in 1991/92 and 2001/02. In a secondary analysis time use patterns for eating and drinking and nutrition provision activities were examined on a base of a representative sample of 12600 private households. Surprisingly the amount of time spent on eating and drinking increased over the period. More Germans ate away from home at least once a day, whereas meals at home were still dominant. Moreover comparisons over time revealed that the share in household and food provisioning work has narrowed between men and women, especially in households with both partners being employed. Overall the analysis shows that time use data allow general statements regarding the amount and changes of time spent on daily eating, household work and especially food provision activities. The extent of women's employment has shown to be most decisive for an equal division of household work between gender. To be able to better interpret the results and to understand the consequences for family life, it is necessary to complement time use data with qualitative interviews to gain comprehensive insight into peoples nutrition goals, motives and barriers of action.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.583-590
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• 2008

최근 작업자 숙소 및 이송용 외에 작업용으로 사용 가능한 Barge선의 일종인 Accommodation Work Barge 선의 건조량이 증가 추세인 바 현재 중국에서 건조 중인 해당 선박의 HVAC & Refrigeration system에 대하여 정리하였다. 본 시스템은 R404A Direct expansion 냉각방식 (직접팽창방식)이 적용되었으며 HVAC system 중 Air conditioning 부분에 대해서는 선박의 각 Deck 기준으로 Zoning 하여 개별적인 Air handling unit와 Condensing unit를 구성하였으며 (각 unit의 용량은 필요용량의 100%), 냉동 창고의 Refrigeration system은 해당 격실 (육고, 어고, 야채고)에 각각 Unit cooler를 설치하고, Condensing unit를 기계실에 설치하였다. 장비는 전체 용량 100%에 대하여 항시 운전하는 100% 용량의 장비와 비상시에 운전하는 100% 용량의 예비 장비로 구성된다. 냉동 창고에 인접한 Dry provision store는 냉동 창고와는 별개로 중앙 공조기로부터의 냉각 공기를 이용하여 Spot cooling하였다. 본 System의 구성에 대한 장점 및 단점은 아래와 같다. 1. Air conditioning system이 각 Zone에 대하여 구성되므로 각 Zone에 대하여 제어가 가능하다. 2. Air con. 실에 Air handling unit와 Condensing unit가 설치되므로 냉매 배관의 길이가 짧다. 3. Air con. 실에 Air handling unit와 Condensing unit가 설치되므로 실내의 Maintenance space 상에 여유가 없다.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.73-81
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• 1997

In this paper, it is intended to present more reproducible and quantitative method for adhesion assemssement. In scratch test, micromechanical analysis on the stress state beneath the indenter was carried out considering the additional blister field. The interface adhesion was quantified as work of adhesion through Griffith energy approach on the basis of the analyzed stress state. The work of adhesion for DLC film/WC-Co substrate calculated through the proposed analysis shows the identical value regardless of distinctly different critical loads measured with the change of film thickness and scratching speed. On the other hand, uniaxial loading was imposed on DCL film/Al substrate, developing the transverse film cracks perpendicular to loading direction. Since this film cracking behavior depends on the relative magnitude of adhesion strength to film fracture strength, the quantification of adhesion strength was given a trial through the micromechanical analysis of adhesion-dependence of film cracking patterns. The interface shear strength can be quantified from the measurement of strain $\varepsilon$s and crack spacing $\lambda$ at the cessation of film cracking.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.48-56
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• 2009

In this paper, laser-assisted machining(LAM) has been employed to machine hot isostatically pressed (HIPed) Si3N4 work pieces. Due to little residual flaws and porosity, HIPed $Si_3N_4$ work pieces are more difficult to machine compared to normally sintered $Si_3N_4$ workpieces. In LAM, the intense energy of laser was used to enhance machinability by locally heating the workpiece and thus reducing yield strength. In experiments, the laser power ranges from 200W to 800W and the diameter of work pieces is 16mm. While machining, the surface temperature was kept nearly constant by laser heating except for a short period of rise time of max. 58 seconds. Results showed as feed rate increases the surface temperature of $Si_3N_4$ workpieces decreases slightly, whereas the effect of depth of cut is disregardable. With a laser power of 800W, achievable maximal depth of cut as 0.7mm and feed rate was 0.03mm/rev.