• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.67-74
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• 2009

To study the influence of the rotifer Brachionus calyciflorus on harmful algal bloom suppression, we focused on assessing the rotifer's abilities using several prey species : Microcystis aeruginosa, Synechocystis sp., Chlorella vulgaris and Coelastrum sp. of the warm-weather species and the cold-weather centric diatom Stephanodiscus hantzchii. Grazing effects and growth rates of rotifers B. calyciflorus were 94.5% and $1.29d^{-1}$, respectively, for Synechocystis sp., 87.4% and $0.60d^{-1}$, respectively, for M. aeruginosa, 95.2% and $0.65d^{-1}$, respectively, for C. $vulgaris^{TM}$, 78.6% and $0.45d^{-1}$, respectively, for C. vulgaris UTEX., 86.5% and $0.99d^{-1}$, respectively, for Coelastrum sp., and 82.6% and $0.40d^{-1}$, respectively, for S. hantzchii. Of these, although the growth of Synechocystis and Coelastrum was effectively suppressed by rotifer grazing, efficient suppression effects on Stephanodiscus blooms were unexpected. The present study revealed that reproduction of B. calyciflorus was greatly influenced by its food types in the initial stages and the efficiencies of bio-agents as sole food sources vary depending on the target algae and the agent.

• The Journal of Korean Society for School & Community Health Education
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• v.17 no.1
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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.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5035-5042
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• 2014

Background: Knowledge and individual perceptions about adverse effects of all forms of tobacco exert direct influence on the level of tobacco consumption in various socio-demographic groups. The objective of this study was to determine the nature, extent and demographic correlates of knowledge, attitudes and perceptions of use of tobacco among adults in low and middle income countries. Materials and Methods: The Global Adult Tobacco Survey, conducted in fourteen different countries from 2008-2010, was sourced for the data analyzed in this study. Descriptive statistical analyses were conducted to determine the prevalent knowledge and individual perceptions amongst adults about all forms of tobacco consumption. Results: There was relatively high awareness about the harmful effects of smoking tobacco with main awareness being about its relationship with lung cancer (>90% in most countries). In contrast, there was relatively low awareness about harmful effects of smokeless tobacco (< 90% in all countries except India and Bangladesh), and observed correlation of smoking tobacco with heart attack (40.6% in China, 65.1% in India) and stroke (28.2% in China, 50.5% in India). Conclusions: A large proportion of adults living in low and middle income countries possess adequate knowledge about smoking tobacco but have inadequate awareness as well as false perceptions about smokeless forms of tobacco. Popular beliefs of inverse relationships of tobacco consumption with knowledge, attitudes and perception of populations towards tobacco are challenged by the findings of this study.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.968-973
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• 2003

As environmental restrictions have continuously become more strict, it has emphasized development of environment-friendly technologies. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on worker's health and working environment and, hence, recently there have been numerous attempts to minimize harmful effects of cutting fluids on environments. To minimize the use of cutting fluids in machining, conventional cutting fluids have been replaced with the technologies of pressurized cold air and minimum quantity lubrication(MQL). Compared with milling, turning is a continuous cutting process, where tools are continuously heated up and lack of lubricity could lead to tool wear and deteriorated surface roughness. In this study, it has been investigated how tool wear and surface roughness could be affected by cutting conditions, supply and cooling methods. The experimental results show that MQL technology is able to minimize harmful effects of conventional cutting fluids.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.167-178
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• 2016

Spectrum sensing in cognitive radio (CR) has a great role in order to utilize idle spectrum opportunistically, since it is responsible for making available dynamic spectrum access efficiently. In this research area, collaboration among multiple cognitive radio users has been proposed for the betterment of detection reliability. Even though cooperation among them improves the spectrum sensing performance, some falsely reporting malicious users may degrade the performance rigorously. In this article, we have studied the detection and nullifying the harmful effects of such malicious users by applying some well known outlier detection methods based on Grubb's test, Boxplot method and Dixon's test in cooperative spectrum sensing. Initially, the performance of each technique is compared and found that Boxplot method outperforms both Grubb's and Dixon's test for the case where multiple malicious users are present. Secondly, a new algorithm based on reputation and weight is developed to identify malicious users and cancel out their negative impact in final decision making. Simulation results demonstrate that the proposed scheme effectively identifies the malicious users and suppress their harmful effects at the fusion center to decide whether the spectrum is idle.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.3
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• pp.271-279
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• 1998

This study was conducted to compare the serum composition and urinary excretion in four institutional groups and the effects of intakes of good foods and harmful foods according to the Sasang constitiution for a short time on serum and ruine compositon. The contitutions of 33 female stucdents were classified by O-ring test and muscular strength test according to the Sasang constitution, The number of each institutional group was So-yang-in 11, So-em-in 10 and Tae-em-in 12. No subject belonged to Tae-yang-in There were no significant differences among contitutional groups in the values of most serum composition and urinary excretion Serum levels of total cholesterol, glucose, calcium and phosphorus in Tae-em-in was the highest among groups and the level of albumin and total protein in So-em-in was highest. The values of serum compositions changed after the 33 subjects took good foods and then harmful foods according to The Sasang constitution for a short time(5 days). Dietary behavior of the subjects had some effects among the constitutional groups in the values of most serum composition and urinary excretion. But the effects of dietary behavior on the serum composition and urinary excretion showed various trends in the four institutional groups.

• Proceedings of the SCSK Conference
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• 1992.09a
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• pp.69-78
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• 1992

It is well hewn that ultraviolet light(UV) penetrates into the skin depends on the wavelength and causes many biochemical reactions in the skin. The enormous amount of information reveals that UV effects sun-burn, sun-tan and photoaging etc. In addition to these, it is now recognized that UV initiates immuno-suppression, and associated with this, skin cancer. In this review, I tried to illuminate the processes of injurious effects of UV on the skin.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.128-135
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• 2003

To decrease environmental damage, the development of environmental friendly fluids provides attractive alternative to the conventional fluids. In this study, the effects of harmful ingredients (Cl, S) contained in the fluids that used in grinding and cutting processes to influence on the nasal cavities of the white rats were measured indirectly. Also, the level of the environmental influence in workshops was graded through analyzing the concentration and chemical ingredients of flying-dust, which generated from the friction and combustion in the cutting process, that for analyzing how harmful the influence of particles to workers then it could be used as the basic data for improving the environment. To improve the conventional machining fluid, which can be harmful on worker's bodies and the environment, the environmental friendly machining method was suggested through analyzing each lubrication properties of vegetable fluid and used-edible oil as alternative fluid. As a result, it was known that an emulsion type fluid might be the main cause leading to some respiratory ailments. Also this paper presents the possibility to use vegetable fluid and used-edible oil as the alternative of cutting fluids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.487-494
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• 2006

The effects of water temperature, salinity and irradiance on the growth of harmful algae Chattonella marina isolated from Gamak Bay in South Sea, Korea were investigated. C. marina was able to grow in temperatures of $15-30^{\circ}C$ and salinities of 10-35 psu. Maximum specific growth rate (0.64/day) was observed with combination of $25^{\circ}C$ and 25 psu. Optimal growth (${\ge}70%$ of maximum specific growth rate) was obtained with all salinities of the above $20^{\circ}C$. This result indicated that C. marina is a stenothermal of the high water temperature and euryhaline organism. C. marina was did not grow at irradiance ${\le} 10{\mu}mol$ photons/($m^2\;s$). Photoinhibition did not occur at $300{\mu}mol$ photons/($m^2\;s$), which was the maximum irradiance used in this study. The irradiance-growth curve was described as ${\mu}=0.78(I-11.4)/(I+34.1)$ at $25^{\circ}C$ and 25 psu. The half-saturation photon flux density (PFD) ($K_s$) was $56.9{\mu}mol$ photons/($m^2\;s$) and compensation PFD ($I_c$) was $11.4{\mu}mol$ photons/($m^2\;s$). The result of the present study indicate that C. marina has advantage physiological characteristic to the interspecific competition at the embayment and costal areas of South and West Sea, Korea in summer.

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.221-226
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• 1998

This study was conducted to develop labor-saving cultural techniques for weed control using herbicides in Rehmannia glutinosa and Astragalus membranaceus, Napropamide, linuron(preemergence) and paraquat (postemergence) showed significant herbicidal effects. At the same time they did not turn out to be harmful to the growth of Rehmannia glutinosa. The yield of Rehmannia, glutinosa treated with paraquat was higher than that of the untreated. Napropamide showed significant herbicidal effect without harmful effects to the growth of Astragalus membranaceus. Etha1flura1in and metolachlor, however, were s1ightly harmful. The yield of Astragalus membranaceus was highest with napropamide.