• Safety and Health at Work
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• v.10 no.4
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• pp.512-517
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• 2019

Background: Rest breaks at work are reported to reduce fatigue and job stress. Apartment janitors in Korea who perform night shift work and work long hours can be exposed to various health problems (HPs). However, few studies have evaluated relationships between their rest breaks and HPs. This study was conducted to examine the relationships between long working hours, shift work, and insufficient rest breaks and HPs among Korean apartment janitors. Methods: Data on 1,212 selected male apartment janitors were obtained from the 3rd and 4th Korean Working Conditions Surveys. Demographic and occupational characteristics were collected using self-reported questionnaires. Rest breaks at work were classified as "sufficient" or "insufficient." Long working hours were considered as working more than 60 hours per week. Zero-inflated negative binomial (ZINB) regression was performed to investigate the effects of shift work and long working hours on HPs and the effects of rest breaks on relationships between HPs and long working hours and shift work. Results: Among those with insufficient rest breaks at work, significant associations were found between long working hours and the risk of HPs [odds ratio (OR) = 1.489; 95% confidence interval (CI) = 1.038-2.136] and work-related HPs (WRHPs) [OR 1.621; 95% CI = 1.156-2.272], and between shift work and HPs [OR = 1.603; 95% CI = 1.084-2.372]. These relationships became nonsignificant when sufficient rest breaks were provided. Conclusion: It is important to provide breaks at work to reduce HPs because of long working hours and shift work among aged workers such as apartment janitors.

• Genomics & Informatics
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• v.14 no.3
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• pp.125-135
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• 2016

Helicobacter pylori is a Gram-negative bacteria that is responsible for gastritis in human. Its spiral flagellated body helps in locomotion and colonization in the host environment. It is capable of living in the highly acidic environment of the stomach with the help of acid adaptive genes. The genome of H. pylori 26695 strain contains 1,555 coding genes that encode 1,445 proteins. Out of these, 340 proteins are characterized as hypothetical proteins (HP). This study involves extensive analysis of the HPs using an established pipeline which comprises various bioinformatics tools and databases to find out probable functions of the HPs and identification of virulence factors. After extensive analysis of all the 340 HPs, we found that 104 HPs are showing characteristic similarities with the proteins with known functions. Thus, on the basis of such similarities, we assigned probable functions to 104 HPs with high confidence and precision. All the predicted HPs contain representative members of diverse functional classes of proteins such as enzymes, transporters, binding proteins, regulatory proteins, proteins involved in cellular processes and other proteins with miscellaneous functions. Therefore, we classified 104 HPs into aforementioned functional groups. During the virulence factors analysis of the HPs, we found 11 HPs are showing significant virulence. The identification of virulence proteins with the help their predicted functions may pave the way for drug target estimation and development of effective drug to counter the activity of that protein.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.621-627
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• 2005

Halitosis is mainly caused by the presence of volatile sulfur-containing compounds (VSC's) produced by proteolytic periodontopathic bacteria in the oral cavity. Various mouth-rinses have been offered on the market as solutions to reduce halitosis. The aim of this study was to find a potent substance for the prevention of halitosis. The halitosis prevention substance (HPS) from cumin seed powder was purified by solvent extraction, silica gel column chromatography and preparative TLC to yield an oil phase (0.98%). Instrumental analysis such as FT-IR, $^1H$-NMR and $^{13}C$-NMR showed that HPS contained an -OH group, -HC=CH-, -COO-, and long chain acyl group. HPS was therefore determined to be 2-hydroxyethyl-${\beta}$-undecenate. HPS inhibited the growth of Fusobacterium nucleatum and Porphyromonas gingivalis, by 72.44% and 64.37% at $1{\times}10^{-2}\;M$, and by 99.85% and 91.62% at $5\;{\times}\;10^{-2}\;M$, respectively. It also inhibited the activity of L-methionine-${\alpha}$-deamino-${\gamma}$-mercaptomethane-lyase (METase), which was produced by oral microbes. Furthermore, the VSC production by oral microbes in the human mouth air decreased with increasing HPS concentration. These results suggested that HPS from cumin seed is an efficient halitosis prevention agent.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2789-2791
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• 1999

This paper deals with the design of the HPS electronic ballast, which consists of the ignitor for turning-up and the resonant converter for driving the lamp. Also it contains Power Factor Controller to improve the electronic efficiencies such as power factor, crest factor, low distortion, etc. To make this circuit, it is necessary to simulate it on the computer before we implement it actually. In this paper, we try to modelize the HPS lamp and ballast, and have experiments with 150 watt-HPS lamp from Kwangjunsa.

• Korean Journal of Health Education and Promotion
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• v.29 no.1
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• pp.109-120
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• 2012

Objectives: The objectives of this study were to assess the implementation status of Health Promoting Schools (HPS) among elementary, middle and high schools and to identify characteristics of the schools that affect the implementation of HPS. Methods: A total of 703 teachers (male 32.2%, females 67.8%) from 70 elementary, middle and high schools in Seoul and Gyeonggi participated in the survey. A 60-item self-evaluation questionnaire was used to assess implementation status of HPS. Results: Implementation of HPS in elementary schools were more favorable than middle and high schools after controling for participants' characteristics, such as age, gender, and their duties at school (<0.001). Being a private school was associated with higher score on implementation of HPS in both elementary (${\beta}$=0.170) and middle/high schools (${\beta}$=0.275). However, being located in rural areas (${\beta}$=-0.409) and having larger number of students (${\beta}$=-0.521) were associated with lower score on implementation of HPS in middle/high schools. Conclusions: Middle and high schools, especially large public and/or rural schools, were less favorable in implementing HPS. Therefore, supporting those schools are necessary and developing evaluation and monitoring system for HPS implementation will contribute to promote students' health.

• Advances in concrete construction
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• v.8 no.3
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• pp.199-206
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• 2019

High performance sandcretes (HPS) are new concretes characterized by particles having a diameter less than 5 mm, as well as very high mechanical strength and durability. This work consists in finding solutions to make sandcretes with good physico-mechanical and durability properties for this new generation of micro-concrete. However, upgrading ordinary sandcrete into high performance sandcrete (HPS) requires a thorough study of formulation parameters (equivalent water/binder ratio, type of cement and its dosage, kind and amount of super plasticizer, and gravel/sand ratio). This research study concerns the formulation, characterization and durability, in a sulphate environment, of a high performance sandcrete (HPS), made from local materials. The obtained results show that the rheological properties of fresh concrete and mechanical strength differ with the mineralogy, density and grain size distribution of sands and silica fume used.

• Korean Medical Education Review
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• v.13 no.2
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• pp.47-57
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• 2011

Purpose: This study was conducted to explore the current usage of high integration mannequin human patient simulators (hereafter HPS) in nursing education. Methods: Thirty-two faculty members in 11 nursing schools participated in this survey. the questionnaire consisted of some multiple-choice questions and open questions to collect data on the experience of faculty members with using HPS as well as quantitative information. Results: The faculty members who used HPS in their classes recognized the need to use simulation in nursing education. They identified the advantages of simulation education as promoting adaptation to the clinical environment(46.9%), promoting self-confidence(28.1%), promoting critical thinking(28.15), and making direct nursing skill practice available(28.1%). However, they considered the obstacles to the use of simulation in nursing education to be insufficient manpower(62.5%), insufficient time(40.6%), and difficulty in preparing a teaching strategy(34.4%). Conclusion: HPS is useful in nursing education, but systematic plans and policies regarding on its operation are needed to confirm its effectiveness. The results of this study generally provide a basic information for use of HPS in nursing education.

• Journal of Power Electronics
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• v.19 no.2
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• pp.549-559
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• 2019

This paper proposes an adaptive sliding mode control (ASMC) strategy with an enhanced optimal reaching law (EORL) for the robust current tracking control of the boost converter based hybrid power source (HPS) in an electric vehicle (EV). A conventional ASMC strategy based on state observers and the hysteresis control method is used to realize the current tracking control for the boost converter based HPS. Then a novel enhanced exponential reaching law is proposed to improve the ASMC. Moreover, an enhanced exponential reaching law is optimized by particle swarm optimization. Finally, the adaptive control factor is redesigned based on the EORL. Simulations and experiments are established to validate the ASMC strategy with the EORL. Results show that the ASMC strategy with the EORL has an excellent current tracking control effect for the boost converter based HPS. When compared with the conventional ASMC strategy, the convergence time of the ASMC strategy with the EORL can be effectively improved. In EV applications, the ASMC strategy with the EORL can achieve robust current tracking control of the boost converter based HPS. It can guarantee the active and stable power distribution for boost converter based HPS.

• Journal of Power Electronics
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• v.9 no.4
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• pp.526-534
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• 2009

This paper introduces the electronic ballast for high pressure sodium (HPS) lamps which provides power regulation during the whole lamp life without using a closed-loop power control system, in spite of large variations of lamp characteristics resulting from lamp aging. The structure of the electronic ballast and the parameters of HPS lamps are described. A mathematical model for the ballast is developed and used for the design and analysis of the ballast. A design procedure is presented to design the ballast which provides intrinsic power regulation over the whole lamp life. To improve the technical specifications of the ballast, the practical and standard constraints are considered in the design. According to the design procedure, an electronic ballast for 250-W HPS lamps is designed. All theoretical analyses are verified with the help of a semi-industrial experimental setup. The results validate that the designed ballast provides power regulation during the whole lamp life.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1304-1306
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• 1996

A regenerative signal amplifying gate driver of self-excited electronic ballast is presented. It can be used for high pressure sodium (HPS) lamp without auxiliary external ignitor. Since the HPS lamp requires very high ignition voltage at start up, the resonant frequency of the circuit must be increased to obtain high voltage oscillations in spite of relatively small resonant current. The presented gate driver amplifies the current of gate drive transformer and raises the gate-source voltage Quickly to turn on the MOSFET switches. Hence, the resonant frequency can be increased more than 100kHz. The HPS lamp used in the simulation and experiment has the rating of 400W input power at 220V input ac voltage source. The experiments show that the resonant frequency is above 150kHz at start up.