• Safety and Health at Work
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• v.6 no.1
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• pp.25-29
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• 2015

Background: Shift work has been associated with occupational stress in health providers and in those working in some industrial companies. The association is not well established in the law enforcement workforce. Our objective was to examine the association between shift work and police work-related stress. Methods: The number of stressful events that occurred in the previous month and year was obtained using the Spielberger Police Stress Survey among 365 police officers aged 27-66 years. Work hours were derived from daily payroll records. A dominant shift (day, afternoon, or night) was defined for each participant as the shift with the largest percentage of total time a participant worked (starting time from 4:00 AM to 11:59 AM, from 12 PM to 7:59 PM, and from 8:00 PM to 3:59 AM for day, afternoon, and night shift, respectively) in the previous month or year. Analysis of variance and covariance were used to examine the number of total and subscale (administrative/professional pressure, physical/psychological danger, or organizational support) stressful events across the shift. Results: During the previous month and year, officers working the afternoon and night shifts reported more stressful events than day shift officers for total stress, administrative/professional pressure, and physical/psychological danger (p < 0.05). These differences were independent of age, sex, race/ethnicity, and police rank. The frequency of these stressful events did not differ significantly between officers working the afternoon and night shifts. Conclusion: Non-day shift workers may be exposed to more stressful events in this cohort. Interventions to reduce or manage police stress that are tailored by shift may be considered.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.39-48
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• 2012

It is well known that software testing amounts for a significant portion of software development cost. In order to reduce the cost of software testing. a lot of researches on automated test data generation have been performed. Sophisticated tools for performing symbolic execution or solving a system of path constraints are required to support automated test data generation. Developing or purchasing those tools leads to another factor of increasing the cost involving software testing. In this paper, we propose a dynamic test data generation approach that does not depend on symbolic execution or constraint solving at all. The proposed approach extends Korel's path-oriented method to satisfy the branch coverage criterion effectively. We conducted an experiment to evaluate the effectiveness of the proposed technique with a triangle classification program to show that branch coverage can be easily achieved.

• Journal of the Korean Ceramic Society
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• v.48 no.3
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• pp.236-240
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• 2011

In order to deposit a homogeneous and uniform ${\beta}$-SiC films by chemical vapor deposition, we demonstrated the phase stability of ${\beta}$-SiC over graphite and silicon via computational thermodynamic calculation considering pressure, temperature and gas composition as variables. The ${\beta}$-SiC predominant region over other solid phases like carbon and silicon was changed gradually and consistently with temperature and pressure. Practically these maps provide necessary conditions for homogeneous ${\beta}$-SiC deposition of single phase. With the thermodynamic analyses, the CVD apparatus for uniform coating was modeled and simulated with computational fluid dynamics to obtain temperature and flow distribution in the CVD chamber. It gave an inspiration for the uniform temperature distribution and low local flow velocity over the deposition chamber. These calculation and model simulation could provide milestones for improving the thickness uniformity and phase homogeneity.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.2 s.314
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• pp.1-10
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• 2007

Branch prediction accuracy is critical for the overall system performance. Branch miss-prediction penalty is the one of the significant performance limiters for improving processor performance, as the pipeline deepens and the instruction issued per cycle increases. In this paper, we propose "Dynamic Per-Branch History Length Fitting Method" by tracking the data dependencies among the register writing instructions. The proposed solution first identifies the key branches, and then it selectively uses the histories of the key branches. To support this mechanism, we provide a history length adjustment algorithm and a required hardware module. As the result of simulation, the proposed mechanism outperforms the previous fixed static method, up to 5.96% in prediction accuracy. Furthermore, our method introduces the performance improvement, compared to the profiled results which are generally considered as the optimal ones.

• The Journal of Korean Academic Society of Nursing Education
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• v.11 no.2
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• pp.270-277
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• 2005

Purpose: This study was to investigate relationships among self-care, self-efficacy and social support in patients with chronic obstructive pulmonary disease (COPD). Method: The subjects were 114 patients with COPD from both inpatient and outpatient department sin a branch hospital of C university located in Gyeonggi-do from April 2005 to May 2005. Self-care was measured by No Hyeon-Suk's (2003) scale, self-efficacy was measured by Wigal et al's (1991) scale, social support was measured by Park Sun-Ju's (2001) scale. Data were analyzed by using t-test, ANOVA, Pearson correlation coefficient, and stepwise multiple regression. Results: The total mean was 3.1 for self-care, 3.5 for self-efficacy, and 4.3 for social support. The levels of self-efficacy and social support were significantly and positively correlated with the level of self-care. The level of self-care was influenced by social support explaining 16% and the level of self-efficacy explaining 6%, giving a total of 22%. Conclusion: The result of this study showed that the patients with COPD carried out self-care better when they had higher levels of self-efficacy and social support. Thus, we will improve the level of self-care of patients with COPD by nursing intervention to increase self-efficacy and social support.

• Journal of Multimedia Information System
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• v.5 no.1
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• pp.43-46
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• 2018

The paper considers the main processes of evolution and convergence of information and communication technologies, which have a permanent source for creation and introduction of innovations in learning and education. The modern scientific and technological revolution gives new features to all modern activities, including activities in the sphere of education, influencing it and transforming its phases, form and content, and perhaps understanding in general. Consequently, general understandings about the essence of the provision of educational services and their technological support are also being transformed. Note that, according to scientists, convergence is a new determinant of the development of society, and evolution is a multidimensional natural process of development (becoming).

• Safety and Health at Work
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• v.14 no.2
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• pp.141-152
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• 2023

Objective: We performed a meta-analysis of epidemiological results for the association between occupational exposure as a firefighter and cancer as part of the broader evidence synthesis work of the IARC Monographs program. Methods: A systematic literature search was conducted to identify cohort studies of firefighters followed for cancer incidence and mortality. Studies were evaluated for the influence of key biases on results. Random-effects meta-analysis models were used to estimate the association between ever-employment and duration of employment as a firefighter and risk of 12 selected cancers. The impact of bias was explored in sensitivity analyses. Results: Among the 16 included cancer incidence studies, the estimated meta-rate ratio, 95% confidence interval (CI), and heterogeneity statistic (I²) for ever-employment as a career firefighter compared mostly to general populations were 1.58 (1.14-2.20, 8%) for mesothelioma, 1.16 (1.08-1.26, 0%) for bladder cancer, 1.21 (1.12-1.32, 81%) for prostate cancer, 1.37 (1.03-1.82, 56%) for testicular cancer, 1.19 (1.07-1.32, 37%) for colon cancer, 1.36 (1.15-1.62, 83%) for melanoma, 1.12 (1.01-1.25, 0%) for non-Hodgkin lymphoma, 1.28 (1.02-1.61, 40%) for thyroid cancer, and 1.09 (0.92-1.29, 55%) for kidney cancer. Ever-employment as a firefighter was not positively associated with lung, nervous system, or stomach cancer. Results for mesothelioma and bladder cancer exhibited low heterogeneity and were largely robust across sensitivity analyses. Conclusions: There is epidemiological evidence to support a causal relationship between occupational exposure as a firefighter and certain cancers. Challenges persist in the body of evidence related to the quality of exposure assessment, confounding, and medical surveillance bias.

• Structural Monitoring and Maintenance
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• v.5 no.3
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• pp.379-390
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• 2018

In this paper, a novel and effective damage diagnosis algorithm is proposed to detect and estimate damage using two stages least squares support vector machine (LS-SVM) and limited number of attached sensors on structures. In the first stage, LS-SVM1 is used to predict the unmeasured mode shapes data based on limited measured modal data and in the second stage, LS-SVM2 is used to predicting the damage location and severity using the complete modal data from the first-stage LS-SVM1. The presented methods are applied to a three story irregular frame and cantilever plate. To investigate the noise effects and modeling errors, two uncertainty levels have been considered. Moreover, the performance of the proposed methods has been verified through using experimental modal data of a mass-stiffness system. The obtained damage identification results show the suitable performance of the proposed damage identification method for structures in spite of different uncertainty levels.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.2
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• pp.25-33
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• 2016

The thermal stratification phenomenon in the nuclear power plant can cause abnormal deformation of the piping, contact with the support, damage to the support system. Repetition of the thermal stratification phenomenon or variation of the thermal boundary layer can cause thermal fatigue. Thermal stratification phenomenon in nuclear power plants is still an ongoing issue and active research has been carried out. In this paper, the current situation in Korean nuclear power plants is described, followed by the status of research and the future problems on the thermal stratification phenomenon in Korea.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.1
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• pp.38-44
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• 2002

60% Pt on Vulcan XC-72 with similar Pt sizes to fuel cell grade Pt black was investigated by $\^$13/C nuclear magnetic resonance spectroscopy (NMR), cyclic voltammery (CV), transmission electron microscopy (TEM). Experiments were carried out on electrochemically cleaned samples as well as as-received. The TEM and CV results showed that the average particle sizes were changed by cleaning. However, the chemical shift （$\delta$$\_$G/） of $\^$13/C of $\^$13/CO absorbed on Pt surfaces did not show any appreciable variation with particle size change as did in Pt black. These results indicate that a combination of different analytic techniques is essential to understand the properties of the metal particle catalysts and that the presence of carbon black support strongly influences the NMR data, probably through metal-support interaction.