• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.799-805
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• 2011

This study presents three different magnetization models for identifying unknown magnetization of the ferromagnetic thin plate of a ship. First, the forward problem should be solved to accurately predict outboard magnetic fields due to the magnetization distribution estimated at a certain time. To achieve this, three different modeling methods for representing remanent magnetization (i.e., magnetic charge method, magnetic dipole array method, and magnetic moment method) were utilized. Material sensitivity formulas containing the first-order gradient information of an objective function were then adopted for an efficient search of an optimum magnetization distribution on the hull. The validity of the proposed methods was tested with a scale model ship, and field signals predicted from the three different models were thoroughly investigated with reference to the experimental data.

• BMB Reports
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• v.53 no.9
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• pp.466-471
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• 2020

Several humanized mouse models are being used to study humanspecific immune responses and diseases. However, the pivotal needs of fetal tissues for the humanized mice model have been huddled because of the demand for ethical and medical approval. Thus, we have verified the hematopoietic and immunomodulatory function of HepaRG and developed a new and easy humanized mouse model to replace the use of fetal liver tissue. HepaRG co-transplanted Hu-NSG mice significantly increased CD45+ lymphocytes and CD19+ B cells and CD3+ T cells than normal Hu-NSG, suggesting enhanced reconstitution of the human immune system. These results have improved the applicability of humanized mice by developing new models easily accessible.

• Journal of Environmental Impact Assessment
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• v.12 no.4
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• pp.291-302
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• 2003

This paper examined the impacts of the regional developments and dwellers behavior on the Seacoast. Seacoast features a variety of landforms which are created by the action of waves and tidal flows. The coastal landforms are found mainly in the interface between land and sea. Although erosional landforms constitute prominent landscape features as sea stack, sea arch, and rock cliff do, it is nonetheless the depositional features such as beaches, tidal flats, offshore bars, deltas, sanddunes, and coastal plains that have various ramifications for human communities. Among these, beaches and coastal sanddunes are special in that their formation is attributable to the combined action of waves, tidal flows, and winds. The main line of discussion in this dissertation is concerned with the transformation of group of beaches sanddunes along the coastline of Chungcheong-Namdo Province. To some extent, the erosion of coastal dunes has been a global phenomenon. The degradation process occurs most actively when the spring tides attack beaches, berms, and foredunes. Also involved in the transformation of coastal dunes are factors of human agency. The extent, speed, and pattern of their morphological changes are a function of land-use pattern. The reclamation of swale and the exploitation of sands as construction material and silica sand, for example, ruin the feature of coastal dunes.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.3
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• pp.289-295
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• 2014

The composition of bright flash device is a pyrotechnic mixture consisting of metal powder, oxidizer and additives. A pyrotechnic mixture of bright flash device generates a bright flash through burning after being ignited by initiator. The function of bright flash is to distract or incapacitate electro optical sensor systems and enemy eyes temporally. This study is to develop composition of pyrotechnic mixture of bright flash and to analyze the test results by considering intensity and efficiency of light.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.4
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• pp.300-306
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• 2016

The gas ventilated by supercavitation splits into smaller bubbles and follows the water passage of the cavitation tunnel. The bubbles quickly return to the test section by rather high speed flow, and interrupt the observation of the supercavitation. To secure clear observation in the test section, the bubble collecting section(settling chamber) of large volume is prepared to collect bubbles in the water passage ahead of the test section. The bubble collecting section should provide enough buoyancy effect to the bubbles for proper bubble collecting. However, rather high-speed oncoming flow produces non-uniform velocity distribution and deteriorates buoyancy effect in the bubble collecting section. In the present study, the bubble collecting space and three porous plates are designed and analyzed through numerical methods, and the bubble collecting function is experimentally validated by 1/10-scaled model in terms of the formation of uniformly low velocity distribution in the bubble collecting section.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.654-667
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• 2003

This paper presents a consequence of the systematic approach to identify the aerodynamic parameters of an unmanned aerial vehicle (UAV) equipped with the automatic flight control system. A 3-2-1-1 excitation is applied for the longitudinal mode while a multi-step input is applied for lateral/directional excitation. Optimal time step for excitation is sought to provide the broad input bandwidth. A fully automated programmed flight test method provides high-quality flight data for system identification using the flight control computer with longitudinal and lateral/directional autopilots, which enable the separation of each motion during the flight test. The accuracy of the longitudinal system identification is improved by an additional use of the closed-loop flight test data. A constrained optimization scheme is applied to estimate the aerodynamic coefficients that best describe the time response of the vehicle. An appropriate weighting function is introduced to balance the flight modes. As a result, concurrent system models are obtained for a wide envelope of both longitudinal and lateral/directional flight maneuvers while maintaining the physical meanings of each parameter.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.409-414
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• 2018

Extrapolating the correction information of ionosphere is essential for expanding wide area differential GPS (WADGPS) service area beyond the reference station network. In this paper, design and analysis of the artificial neural network for expanding the ionospheric correction region will be proposed. First, analysis about influence of each input of neural network were performed. The inputs are the day/year periodic function, sunspot number, and geomagnetic index (Ap). Second, performance analysis with respect to the number of hidden layers and neurons in the neural network is shown. As a result, estimation of total electron contents (TEC) on the high/low latitude regions in solar max(2014) are displayed.

• Journal of Korean Society for Quality Management
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• v.44 no.3
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• pp.487-508
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• 2016

Purpose: Current testing method for drying rate used in military textiles has different results according to the public testing institute. So the purpose of this study was to suggest the alternative method which secure the reliability of the drying rate test. Methods: We measured the drying rate by various test methods for military clothes 14 species including quick drying function and compared the test results. Also, the collected data through the test was analyzed using one-way ANOVA. The p-value of results was compared by various testing institutions. Results: The results of this study are as follow; A deviation occurred among the testing institutions in original test method(KS K 0815). Whereas it is verified that there is no deviation among the institutions in 5% significance level by another test method(ISO 17617). Also it would increase work efficiency by reducing the testing time required to test by using ISO 17617. Conclusion: Based on the results, we can suggest the reliable test method of the drying rate.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.1-13
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• 2020

This study examines the effect of managerial ownership on firm value in capital markets where outside governance mechanisms to discipline managers are weak or non-existent. We hypothesize that strong market forces in the U.S. confound the effect of managerial ownership on firm value, i.e., the convergence of interest argument. We test the hypothesis using data from 112 firms from Singapore Stock Exchange and 205 firms from the Stock Exchange of Thailand prior to the Asian financial crisis in 1997 when the market forces were weak, yet the investor protection was sufficient to prevent outright appropriation from management. For ease of comparison, we use methodologies from studies done on the U.S. sample firms during the same study period as ours. We find that, both in Singapore and Thailand, firm value is a function of managerial ownership, and the relation is of the famous inverted U-shaped. Moreover, the relation is robust under different model specifications. The results from Thai sample, with weaker market forces than in Singapore, lend support to many agency cost hypotheses advanced in the U.S. Our results provide useful implication for investors in emerging and frontier markets where outside governance mechanisms are yet to be fully developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.203-211
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• 2009

In the area of the telecommunication industry, a few products have been developed before related technical regulation has been made. Government agency is forced to make a final decision on whether a requested product is sellable in the market only after the structure and function of requested product is tested. The introduction of a 'SDoC', and 'privatization of technical regulation' to our legal system could be a solution for minimizing the situation mentioned above. Both 'SDoC' and 'privatization of technical regulation' are systems which are capable of minimizing the appearance of products without technical regulations. Furthermore, 'Temporary approval system' would provide a government agency with administrative procedure for new product without technical regulation.