• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.61-70
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• 2015

In an attempt to improve the maneuvering character of hull form renovated tuna purse seiner. A renovation was carried out on the 3 tuna purse seiner fishing vessel. To grasp the progress of maneuvering and resistance on ship B (730 ton class), new bulbous bow was only attached. The ship A (740 ton class) and C (600 ton class) were modified for new bulbous bow, enlarged slipway and rudder. And then the zigzag and the turning test were carried out. According to the turning test, the advance and the tactical diameter were improved very much for the modified ship. The sea trial was carried out for the original and modified ship A. It is showed that the results of sea trial corresponded with that of the tank test on the whole. In the result of the zigzag test on ship B, the turning ability was improved very much, but the yaw checking ability was deteriorated in just some degree. In the result of the zigzag test on ship C, the turning ability and yaw checking ability were remarkably improved. Ship C was greatly improved among the three ships for the maneuvering character of modified hull form.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.57-63
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• 2015

The incidence of fires caused by electrical factors has increased with the growth in domestic electrical consumption. According to the national fire data system of national emergency management agency, electrical fires accounted for 20% of all domestic fires in the last 10 years. Electrical fires are mainly caused by short circuit, leakage current, defect in an electrical equipment, over load, utility fault, etc. The fault current can be several times larger than the nominal current, thereby exceeding the rated current of cable. Consequently, the cable conductor, typically copper wire, heats up to a temperature that ignites surrounding combustibles. This paper describes the transient characteristics of the 0.6/1kV, TFR-8 cable have been investigated, and analyzed under the over current conditions for reduce the risk of electrical fire by experimental and FEM analysis. The experimental and FEM(Finite Element Method) analysis results of temperature and resistance variation according to the over current in copper wires were analyzed. The experimental results coincide well with the FEM analysis.

• Journal of Biosystems Engineering
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• v.32 no.3
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• pp.145-152
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• 2007

Uniformity of spray deposit is one of the important factors in spray performance affecting efficacy of pest management. Distributions of spray deposit on artificial targets were measured and analyzed to enhance the efficiency of spray application. The research was studied to understand the deposition characteristics of spray droplets and to determine the optimum conditions of chemical application. The deposit and its pattern by the lower fan speed was more uniform and higher than that by the higher fan speed. The upward blasting distance was limited within 3 m, but the limit to the ground level was expanded the distance more than 3.5 m because of the accumulated droplets. When the fan speed was higher at the distance of 2.5 m, deposit reached to maximum. When the distance increased, deposit was getting lower. At the both fan speeds, the deposit was concentrated below $30^{\circ}$ because of the gravitation and the resistance of wind. This research can be useful in designing an orchard sprayer and its operation for various tree canopies. To achieve a uniform distribution of deposit using the air-blast type orchard sprayer, the application rate from the middle boom should be increased as the air velocity to the upward increased. The spray rate to the side boom should be limited in a minimal level.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.253-257
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• 2012

The purpose of this study was to investigate the prevalence of Brachyspira species and antimicrobial susceptibility of Brachyspira (B.) hyodysenteriae isolates in Korea. A total of fifty-five Brachyspira species were isolated; five (1.0%) beta-hemolytic Brachyspira species and 50 (10.4%) weak hemolytic Brachyspira species from 116 different diarrheic pig samples and 367 apparently normal pig samples. In farm level, beta hemolytic and weak hemolytic Brachyspira species were detected in 7.4% (5/68) and 19.1% (13/68) of tested pig farms, respectively. By phenotypic and genotypic characterization, all beta hemolytic Brachyspira isolates was classified as group I (B. hyodysenteriae), whereas weak hemolytic Brachyspira species isolates were group III (B. innocens or B. murdochii). B. hyodysenteriae isolates showed high level of minimum inhibition concentrations to macrolide antimicrobials. This study shows that the prevalence of pathogenic B. hyodysenteriae in pigs is low but antimicrobial resistance of the pathogens is high in Korea. This is the first report of the prevalence of Brachyspira group III and antimicrobial susceptibility of B. hyodysenteriae in pigs in Korea. Our results could provide basic data for the management and treatment guidelines of Brachyspira infection.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.10
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• pp.1671-1686
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• 2010

This research presents a fashion adoption process model based on collective selection theory and examines the differences in the consumer adoption process of merchandising types at each stage of the fashion cycle. A questionnaire survey of 472 adult women was conducted for the purpose of empirical analysis of the fashion adoption process. The results show that fashionability and popularity (the primary attributes of fashion goods) have direct effects on resistance and adoption as well as indirectly through social compatibility and personal compatibility in the evaluation stage. In conclusion, on the theoretical side, this study verified the fashion process model according to consumer participation in the adoption process of fashion goods existing at different stage of the fashion cycle, internally through negotiating with individual tastes, and externally through interacting with others. On the practical side, this study presented an empirical result that can apply to merchandizing strategy centered on merchandizing type by connecting consumer adoption for the fashion goods released by actual companies.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.455-461
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• 2010

The tumor microenvironment, particularly sufficient nutrition and oxygen supply, is important for tumor cell survival. Nutrition deprivation causes cancer cell death. Since apoptosis is a major mechanism of neuronal loss, we explored neuronal apoptosis in various microenvironment conditions employing neuroblastoma (NB) cells. To investigate the effects of tumor malignancy and differentiation on apoptosis, the cells were exposed to poor microenvironments characterized as serum-free, low-glucose, and hypoxia. Incubation of the cells in serum-free and low-glucose environments significantly increased apoptosis in less malignant and more differentiated N-type IMR32 cells, whereas more malignant and less differentiated I-type BE(2)C cells were not affected by those treatments. In contrast, hypoxia (1 % $O_2$) did not affect apoptosis despite cell malignancy. It is suggested that DLK1 constitutes an important stem cell pathway for regulating self-renewal, clonogenicity, and tumorigenicity. This raises questions about the role of DLK1 in the cellular resistance of cancer cells under poor microenvironments, which cancer cells normally encounter. In the present study, DLK1 overexpression resulted in marked protection from apoptosis induced by nutrient deprivation. This in vitro model demonstrated that increasing severity of nutrition deprivation and knock-down of DLK1 caused greater apoptotic death, which could be a useful strategy for targeted therapies in fighting NB as well as for evaluating how nutrient deprived cells respond to therapeutic manipulation.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.503-507
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• 2011

Objective: This paper presents the factors influencing the effectiveness of materials handling equipments in agriculture. Background: Agriculture is one of the job categories where work-related musculoskeletal disorders(MSDs) are the most common. Statistics shows that majority of farm workers is exposed to repetitive and forceful body movements, lifting, lowering, pushing, pulling, or carrying heavy materials. In such a working environment, materials handling equipments are required and introduced to assist in the prevention of MSDs and other farm injuries. Method: Examples of materials handling equipments are rail carts, portable lifts, and bale handlers. Contributing factors influencing the effectiveness of materials handling equipments supplied in agriculture were identified based on the lessons learned from previous government-funded ergonomic projects. Results: Contributing factors identified include: (1) forward-looking attitude for the standardization of farming, its environments, and handling equipments, (2) participation of farm members in the process and evaluation of project, (3) leadership of project manager, (4) reinforcement of safety education and training, and (5) project selection and priority of handling equipment. Conclusion: Government-funded research planners, farmers, ergonomists, and farm machine experts are recommended to consider the factors identified when implementing materials handling equipments in agriculture. Application: Actual or potential application of this research includes recommendation for the effective implementation of material materials handling equipments in agricultural sectors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.5
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• pp.270-275
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• 2017

Current progress in the development of semiconductor technology in applications involving high electron mobility transistors (HEMT) and power devices is hindered by the lack of adequate ways todissipate heat generated during device operation. Concurrently, electronic devices that use gallium nitride (GaN) substrates do not perform well, because of the poor heat dissipation of the substrate. Suggested alternatives for overcoming these limitations include integration of high thermal conductivity material like diamond near the active device areas. This study will address a critical development in the art of GaN on diamond (GOD) structure by designing for ideal heat dissipation, in order to create apathway with the least thermal resistance and to improve the overall ease of integrating diamond heat spreaders into future electronic devices. This research has been carried out by means of heat transfer simulation, which has been successfully demonstrated by a finite-element method.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1690-1695
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• 2007

Lightweight metallic truss structures with open, periodic cell are currently being investigated because of their multi-functionality such as thermal management and load bearing. The Kagome truss PCM has been proved that it has higher resistance to plastic buckling, more plastic deformation energy and lower anisotropy than other truss PCMs. The subject of this paper is an examination of the failure mechanism of Wire woven Bulk Kagome(WBK). To address this issue, the out-of-plane compressive responses of the WBK has been measured and compared with theoretical and finite element (FE) predictions. For the experiment, 2 multi-layered WBK are fabricated and 3 specimens are prepared. For the theoretical analysis, the brazed joints of each wire in WBK are modeled as the pin-joint. Then, the peak stress of compressive behavior and elastic modulus are calculated based on the equilibrium equation and energy method. The mechanical structure with five by five cells on the plane are constructed is modeled using the commercial code, PATRAN 2005. and the analysis is achieved by the commercial FE code ABAQUS version 6.5 under the incremental theory of plasticity.