• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.12-14
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• 2022

통신과 소재, 센서의 발전은 다양한 분야에서, 다양한 제품 개발을 유도하였다. 항로표지 또한 이러한 기술적인 변화의 흐름에 부합하기 위해 다양하게 진화 하고 있는 중이다. 기존에 기술적 측면에서 고려되어 앞으로 상용화 될 것이라 예측했던 각종 장비 및 기술들이 현실에 적용되기 시작하였다. 드론의 경우 택배, 농업, 소방, 해양안전등 다양한 방면에서 개발이 진행되어 상용화 되고 있으며, 자율주행 차량의 경우도 실제로 제품이 출시되어 운전자가 운전대를 조작하지 않고 숙면을 취하는 내용을 언론매체를 통해 종종 접하고 있다. 이러한 기술 및 장비가 과연 얼마나 항로표지에 적용되어 사용되고 있는지 알아보고 향후 나아갈 방향에 대해서 알아보도록 한다.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.684-693
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• 2012

The stormwater runoff from the increasing paved roads and vehicles resulted in the increase in the pollutants load to adjacent water bodies. The granular media filtration facilities are the most widely adopted to minimize the non-point source pollution from motorways. It is essential to consider the severe variation of hydraulic condition, suspended solid (SS) characteristics, and the medium characteristics for stormwater management filter. In this study, different types of media, including sand, were tested and the performance of downflow sand filters was investigated under various linear velocity and influent solid particle size. Results showed that the best medium is the coarse sand with large grain size, which showed the specific SS removal before clogging of more than $8.498kg/m^2$, the SS removal of higher than 95%, and minimum head loss. Linear velocity did not affect the total solid removal, while the performance was improved when fine solid was introduced. It is suggested that the life of a downflow sand filter bed can be extended by deep bed filtration when influent particles are fine. However, the captured particles can be washed out after a long period of operation.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.256-261
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• 2014

This study was carried out to determine the effect of the artificial pollination on fruit set, seed formation and fruit quality in kiwifruit and to confirm the effective pollination time for optimal fruit set in the shelter greenhouse cultivation. Also, the effect of artificial pollination practice by the pollen diluent solution was tested. By artificial pollination, fruit set, seed formation, and fruit quality was improved both in the open field condition and in the shelter greenhouse cultivation. In order to find the effective pollination period (EPP), artificial pollination was carried out every day until 7 days after full bloom. Number of seeds and fruit set rate and fruit growth of kiwifruit were no significantly different until 4 days after full bloom (DAFB), but, those of kiwifruit from 5 DAFB significantly decreased. Consequently, the effective pollination period of kiwifruit in the shelter greenhouse was 4 days after full bloom. Also, artificial pollination by the pollen diluent solution was showed the similar fruit set and fruit quality compare to that by lycopodium powder. Accordingly, artificial pollination by the pollen diluent solution should be very effective practice for labor saving in kiwifruit cultivation.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.365-370
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• 2019

In this study, effects of the ultrasonic irradiation during the reaction process were investigated for the enantioselective kinetic resolution (EKR) reaction of racemic epoxides in the presence of chiral cobalt salen catalysts, as compared to that of using the conventional mechanical stirring. In order to compare catalytic activities, the chiral cobalt salen complexes having $AlCl_3-$, $BF_3-$ and nitrobenzenesulfonic acid (NBSA) were synthesized and used as catalysts, and then three kinds of the racemic epoxides such as ephichlorohydrine (ECH), epoxy phenoxypropane (EPP) and propylene oxide (PO) were used as reactants. In addition, EKR reactions have been performed using the water and methanol as nucleophiles, respectively. The unique contribution of ultrasonic irradiation as a powerful mixing medium was evaluated in this study to improve the kinetics in comparison to the conventional mechanical agitation during EKR reactions. The reaction time to obtain the highest 99 ee% became shorten more than that of above 60%, when the ultrasonic irradiation was used. This result may be interpreted by the cavitation effect of ultrasound in the solution, generating a powerful shear force for the very violent mixing.

• Korean Journal of Legislative Studies
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• v.25 no.2
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• pp.5-33
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• 2019

This study aims to explore the implications of the 2019 European Parliament elections. Existing studies show that European elections serve as secondary elections dominated by domestic issues. However, the 2019 European elections have highlighted pan-European issues such as the Brexit negotiations and the rise of far-right populism, with voter turnout also rising sharply to 50.62%, which is the highest record since the 2000s. There was also a significant change in the number of parliamentary seats held by each political group. First, the European People's Party(EPP) and the Progressive Alliance of Socialists and Democrats(S&D), which had hitherto led the European Parliament, failed to achieve a majority. Second, the number of seats won by Renew Europe, a new liberal-centrist group, was considerably high. Third, the far-right groups organized a full-fledged political force by rallying around the Identity and Democracy(ID) group. The rise of liberal-centrism can be explained as a reaction to the popularity of anti-European populism. Renew Europe's emphasis on open-market competition has created a different issue, especially since the center-left and center-right groups have stressed on the need for state intervention in employment, welfare, security and immigration control. Along with far-right populism, liberal centrism has also reshuffled Europe's political cleavage, and the conflict between 'liberalism' and 'protectionism' has become more evident in the European Parliament.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.572-577
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• 2012

Recently porous polymer has widely been applied to packaging, heat isolation, and sound absorption in various fields from the electrics to the automobiles industry. A lot of micro porosities inside foamed polymer provide lower heat conduction and lighter weight than non-porous polymer, because they involve gas or air during foaming process. In this paper experimental approaches of the UV laser micro machining behavior for Expanded Polypropylene (EPP) foamed polymer materials, which have different expansion rates, were investigated. From these results, the ablation phenomena were finally observed that the ablation is depended upon stronger photo-chemical than photo-thermal effect. This study will also help us to understand interaction between UV laser beam and porous polymer.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.12
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• pp.1250-1256
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• 2012

Resilient materials are used to reduce the floor impact sound in apartment buildings. Since an on-dol layer is installed in the resilient materials' upper part, thickness deformation can be occur in the resilient material. It is necessary to check a thickness deformation grade for a long period of time. In this research, we measured thickness deformation over 400th day to the resilient materials(EPP, EPS, EVA) which is used in Korea. Although there was a difference according to the kind of measurement test specimens, it became clear that thickness was decreases as to time increased. The thickness deformation grade of ten years after was calculated based on the thickness measurement result. Compare with the calculated result and result of ISO 20392. Larger thickness deformation occurred in the measurement result of these research findings compare with the ISO standard.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.8 no.2
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• pp.263-268
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• 2005

Erythropoietic protoporphyria is a genetic disorder due to a deficiency of ferrochelatase resulting in excessive accumulation and excretion of protoporphyrin. The predominant clinical feature is photosensitivity. Severe hepatic failure occurs in a small percentage of patients, and neurological symptoms are very rare. We report a case of erythropoietic protoporphyria associated with severe hepatic dysfunction and neurological symptoms. A 9-year-old girl presented with severe abdominal pain, nausea, weakness and pain of extremities, and urinary retention. Ultrasonogram and abdominal CT scanning revealed a diffuse infiltrated and enlarged liver. Liver biopsy showed deposition of dense dark brown pigment within the bile, hepatocytes and Kupffer cells. Plus, dense dark brown deposits gave a red birefringent under polarize light. Porphyrin studies demonstrated markedly elevated serum free erythrocyte protoporphyrin. This girl was diagnosed as erythropoietic protoporphyria with severe liver dysfunction and neurological symptoms.

• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.125-134
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• 2006

Among the various physiological factors that affect nerve conduction velocity (NCV), temperature is the most important. Because the influence of temperature is the most important source of error. It is known from animal experiments that conduction is eventually completely blocked at low temperatures, the myelinated A fibers being the first affected and the thin fibers of group C the last. Many studies showed that the NCV decreases linearly with lowering temperature within the physiological range. The distal motor latency increased by $0.2msec/^{\circ}C$ drop in temperature between $25^{\circ}C$and $35^{\circ}C$ in the median, ulnar and peroneal nerves. The temperature affect the neuromuscular transmission; The miniature endplate potential (MEPP) and endplate potential (EPP) are increase with increasing temperature. In myasthenia gravis, the reduction in the decremental response is observed following cooling. The lowering temperature make increase the amplitude of sensory compound action potential; make enlarge the surface area of compound muscle action potential with very little increase in amplitude; make diminish the fibrillation potential and increase the myotonia in needle electromyography (EMG). Because of these findings mentioned above, the skin temperature should be routinely monitored and controlled during nerve conduction tests and needle EMG and should be taken into account when interpreting the findings.

• Journal of Korea Trade
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• v.26 no.5
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• pp.39-55
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• 2022

Purpose - This study empirically examines the effect of the Korean government export promotion program (EPP) on small and medium-sized enterprise (SMEs) export performance using firm-level data. Unlike most previous studies that investigated some specific samples of firms, this study analyzes a vast amount of SME data of the Korean Small and Medium Business Administration over the period 2005 to 2008. Design/methodology - An endogeneity problem arises when a firm's probability of being selected is correlated with the likelihood of successfully implementing EPPs. To control for the endogeneity of the EPPs in a relatively short-period sample, we employ 2-Stage Residual Inclusion (2SRI) RE-Tobit and bivariate Tobit procedure. Findings - Analyses show that Korean government EPPs have positive significant effects on SME exports. Empirical results also show that SME export activities are significantly encouraged by R&D investment and capital intensity, but not obviously by labor productivity. Originality/value - This study provides evidence that SME capital intensity, R&D investment, and the number of workers are significant determinants to SME exporting activities, whereas per worker labor cost and employee education are not. These results imply that even for SMEs, firm size is a major factor in promoting exporting activities.