• International Journal of Industrial Entomology and Biomaterials
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• 제2권1호
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• pp.75-78
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• 2001

The whitefly, Dialeuropora decempuncta Quaintance and Baker (Homoptera : Aleyrodidae) causing considerable damage to mulberry, Morus alba. Crop loss caused by the whitefly was estimated in mulberry. Quantitative yield loss was estimated on the basis of harvest data from both sprayed and unsprayed plots. Data on pest incidence has been recorded at weekly intervals in both sprayed and unsprayed plots from 30 th day of plant age till harvesting i.e., 60 days after pruning in August October season. An attempt has been made to establish a relationship between whitefly population and percentage of crop loss due to it. Percentage of crop loss due to whitefly has got a linear relationship with the whitefly population. An initial population of 24 adults/top leaf would be able to cause 24% loss (l,630 Kg leaf/ha ) in a period of 30 days. Economic analysis postulates that application of pesticide can stove a net amount of 1,630 Kg leaf/ha which is sufficient to produce 67.65 Kg of additional multivoltine cocoons. This determines the cost/benefit ratio which will enable to workout the economics of management practices.

• 대한인간공학회지
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• 제16권3호
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• pp.49-60
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• 1997

Although the tasks are being mechanized or automated today, many tasks are still performed manually in several industrial settings. Manual materials handling and improper sorking postures are known to be a major cause of low back injuries, which are one of the major problems in the economic and public health aspects. In this study, two machine repair shops of a manufacturing company in Pohang were recommended by the company health care center to investigate the potential risk factors that may cause low back injuries. Five machine repair tasks were selected from each machine repair shop, which are accountable for relatively high complaints of low back pain. The purpose of this study is to quantitatively evaluate the hazards of the tasks, and finally to recommend the improved methods and guidelines for safe work practices. In order to accomplish this goal, the questionnaire study and ergonomic evaluations were carried out and the results were analyzed. For most of the tasks under study, workers were found to be exposed to relatively high biomechanical stresses in low back, mainly due to the heaby objects handled and the improper working postures.

• 보건교육건강증진학회지
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• 제15권2호
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• pp.199-215
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• 1998

The health care environment exerts tremendous influence on community health practices. Here the author mention several major factors that will influence the future plan for health service and health education; that is, economic problem, the issues of decrement of infectious disease, increment of chronic degenerative disease due to natural increase of the elderly, increased frequency of traffic and industrial accidents and the issues of medical-technological advances etc. Therefore, special efforts by health personnel should be made to develop health education and health promotion strategies on a community-wide basis. Accordingly, the flexible accessibility, convenient availability, guaranteed medical service, sufficient supply of health information, and rapidly available medicaid service for special population such as the elderly, the handicapped, the disabled and the poor are considered. Also, the financial support from the central government and local self-government and active participation of health consumer to health service are needed in Korea, The role of the health personnel is to elicit, facilitate and maintain health promoting behavior with his and her assurance for health consumers being competent and supported in the voluntary choice of their health promoting activities. The health promoting activities such as the above mentioned will be produce escalation of their life Quality among Koreans.

• 한국환경과학회지
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• 제25권7호
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• pp.927-935
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• 2016

Dissolved oxygen is necessary for many biological processes as well as many industrial practices. Dissolved oxygen released from water in dissolved air flotation (DAF) systems can be have many different applications. However, DAF systems are very costly to operate. To develop more efficient DAF systems, a deeper understanding of the process of oxygen being released from water is required. In this study, molecular dynamics (MD) simulations were used to simulate 100 oxygen molecules surrounded by 31002 water molecules at temperatures ranging from $0^{\circ}C$ to $100^{\circ}C$. Simulations were carried out for 10 ns, during which, in most cases, all the oxygen molecules were released from the water droplet. With MD simulations, visualization of the molecules escaping the water droplet was possible, which aided the understanding of the interactions between molecules at the nano-scale. The results showed that as the oxygen molecules moved near the edge of the water droplet that the oxygen molecules hesitated before escaping the water droplet or returned to the interior of the water droplet. This was because of the attractive forces between the water and oxygen molecules. Moreover, after most of the oxygen molecules were released from the droplet, some were found to return to the droplet's edge or even the interior of the droplet. It was also confirmed that oxygen molecules were released at a faster rate at higher temperatures.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.34-39
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• 1999

In search of a method to achieve sustainable agricultural practices, a trickling filter was employed for the piggery wastewater treatment, where rice straw was the support medium in place of more commonly used materials. The filtrate from the trickling filter were applied to a soil, on which orchard grass (Dactylic glomerata L.) was grown followed by amendment of the treated straw medium. Orchard grass was cut twice, and growth parameters and yields were measured. Soil chemical properties before and after harvesting orchard grass were analyzed. Development of the forage crop was greatly enhanced by the application of the filtrate in terms of fresh weight, dry weight, and the absorption of nutrients. Better growth and higher nutrient uptake were found in the second cutting of the orchard grass. Organic matter content, ionic intensity, exchangeable cations, and phosphate of the soil increased with the application of the filtrate. The relative high concentrations of salts in the piggery trickling filtrate, expressed in electrical conductivity and content of sodium, exerted no detrimental effect on the crop and soil.

• Journal of Biosystems Engineering
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• 제35권5호
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• pp.323-329
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• 2010

Physical damages on fruits may be caused by shock and vibration inputs that transmitted from the transporting vehicle through the packaging and cushioning materials to the fruit. In this study, both half sine shock test and trapezoidal shock test were performed by MIL-STD-810F specification in order to investigate and represent the shock response properties such as peak acceleration and shock amplification factors of the pear according to packaging and cushioning materials for optimal packaging design during transportation. Shock excitation data that had been measured on the vehicle operating on the real road were used. Shock response properties measured by half sine shock test were smaller than those measured by trapezoidal shock test. Results represent that corrugation shapes and thickness can significantly affect the cushioning performance than the paper configurations of cushioning pad and showed that fruits may be damaged seriously while transported on the unpaved road without the properly cushioned packaging practices.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2170-2178
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• 2015

This paper presents the effective and reliable speed control of PMDC motors under variable loads and reference speeds. As is known DC motors are more preferred in industrial practices. This is that, the PMDC motors don’t require brush and commutator care and to increase in torque per motor depending on developments in power electronics. In this study, proportional-integral controller (PI) and fuzzy logic controller (FL) have been designed for speed control of PMDC motor. In the design of these controllers, characteristics such as minimum overrun time, response time to the load, settling time and ideal rise time have been taken into consideration for better stability performance. In this design, the best system response was searched by examining the effect of different defuzzification methods onto the fuzzy logic system response. In conclusion, it has been seen that FL controller has a better performance for variable speed-load control of PMDC motor compared to PI controller.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2005년도 추계학술대회 및 정기총회
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• pp.388-393
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• 2005

Private peering, public peering and transit are three common types of interconnection agreements between providers in the Internet. An important decision that an Internet service provider (ISP) has to make is which private peering/transit ISPs and Internet exchanges (IXs) to connect with to transfer traffic at a minimal cost. In this paper, we deal with the problem to find the minimum cost set of private peering/transit ISPs and IXs for a single ISP. There are given a set of destinations with traffic demands, and a set of potential private peering/transit ISPs and IXs with routing information (routes per destination, the average AS-hop count to each destination, etc.), cost functions and capacities. Our study first considers all the three interconnection types commonly used in real world practices. We show that the problem is NP-hard, and propose a heuristic algorithm for it. We then evaluate the quality of the heuristic solutions for a set of test instances via comparison with the optimal ones obtained by solving a mixed integer programming formulation of the problem. Computational results show that the proposed algorithm provides near-optimal solutions in a fast time.

• 산경연구논집
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• 제7권2호
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• pp.13-20
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• 2016

Purpose - The purpose of this research is to discover whether the presence of the product average rating introduces biases or change the way people perceive information. We posit that review's overall rating has a predisposition effect on consumers' perception towards detailed review information. Research design, data, and methodology - To test these hypotheses, we conducted an empirical study on a real-world setting of online shopping platform. We choose the Amazon website to test our results. The data we use were collected by the Stanford Network Analysis Project1 (McAuley et al., 2013). Results - With a dataset containing reviews of seven product categories from amazon.com., our findings could possess more generalizability as they are produced on the typical and influential online market. Second, as our research provides alternative views of consumers' shopping behavior, it is better to test our hypotheses by data from the same source. Conclusions - Our study reveals the impact of the collective rating presence on consumers' diagnosticity perception and sheds light upon some of the conflictive results in prior studies. Our research generates implications to both theories and business practices, and suggests future directions for the research question.

• 산경연구논집
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• 제9권2호
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• pp.17-26
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• 2018

Purpose - The purpose of this study is to provide a formalized process of decision making for companies or organizations that need to make various decisions in the age of uncertainty. Therefore, this study aimed to proposes a strategic decision-making approach citing the relatively easily accessible using IPA(important-performance analysis) and SWOT/AHP analysis. Research design, data, and methodology - To be specific, the first step is to derive necessary attributes and conduct IPA. The second step is to subdivide the IPA results into internal strength and weakness factors and the external opportunity and threat factors, hierarchize those factors, and weight them accordingly. The third step is to build a causality model to propose a method of supporting a rational decision making. Results - The foregoing approach seems to facilitate the diversification of decision-making strategies by helping businesses or organizations to measure and analyze the attributes needed for certain decisions. Additionally, the perceived importance and satisfaction (or achievement) usage of those derived attributes can be used as the reference data for SWOT/AHP analysis. Conclusions - The proposed stepwise approach is applicable to businesses or organizations in need of making stepwise decisions in line with their retained competencies in comparison to conventional or intuitive decision-making practices.