• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.175-181
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• 2024

In electrical power substations, bulky iron-core potential transformers (PTs) are installed in a tank of gas-insulated switchgear (GIS) to measure system voltages. This paper proposed a low-power voltage transformer (LPVT) that can replace the conventional iron-core PTs in response to the demand for the digitalization of substations. The prototype LPVT consists of a capacitive voltage divider (CVD) which is embedded in a spacer and an impedance matching circuit using passive components. The CVD was fabricated with a flexible PCB to acquire enough insulation performance and withstand vibration and shock during operation. The performance of the LPVT was evaluated at 80%, 100%, and 120% of the rated voltage (38.1 kV) according to IEC 61869-11. An accuracy correction algorithm based on LabVIEW was applied to correct the voltage ratio and phase error. The corrected voltage ratio and phase error were +0.134% and +0.079 min., respectively, which satisfies the accuracy CL 0.2. In addition, the voltage ratio of LPVT was analyzed in ranges of -40~+40℃, and a temperature correction coefficient was applied to maintain the accuracy CL 0.2. By applying the LPVT proposed in this paper to the same rating GIS, it can be reduced the length per GIS bay by 11%, and the amount of SF6 by 5~7%.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.222-229
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• 2024

As the operating condition for the penetrating missile has been more advanced, the survivability of main charge has been strongly required when the warhead impacts the target. Lots of efforts to desensitize explosives such as the development of insensitive molecular explosives or optimizing plastic-bonded explosives(PBX) systems has been made to enhance the survivability of main charge. However, these efforts face their limits as the weapon system require higher performance. Herein, we suggest a new strategy to secure the survivability of main charge. We applied structurally supportable aluminum honeycomb(HC) structure to cast PBX. The aluminum HC structure reinforces the mechanical strength of cast PBX and helps it to withstand external pressure without the reaction like detonation. In this study, impact resistance character, shock sensitivity and internal blast performance of PBXs reinforced with HC structure were investigated according to the application of aluminum HC structure. The newly suggested aluminum HC structure applied to cast PBX was proved to be a promising manufacturing method available for high-tech weapon systems.

• Journal of Korean Medicine Rehabilitation
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• v.34 no.3
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• pp.53-63
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• 2024

Objectives This study aims to analyze the effectiveness of manual therapy for the treatment of plantar fasciitis by reviewing existing randomized controlled trials. Specifically, it seeks to identify various manual therapy techniques and evaluate their applicability in clinical settings. Methods The study reviewed literature from six databases (PubMed, the Cochrane Library, China National Knowledge Infrastructure, ScienceON, Research Information Sharing Service, Korean studies Information Service System) up to April 2024. Studies were selected based on criteria including randomized controlled trials involving manual therapy for plantar fasciitis. Results An analysis of ten studies involving 714 patients revealed the use of techniques such as joint mobilization, muscle relaxation, and pressure point techniques. Manual therapy was found to be more effective in reducing pain than both extracorporeal shock wave therapy and routine physical therapy alone. However, caution is needed in generalizing these results due to the limited number of studies analyzed. No significant adverse effects were reported. Conclusions Manual therapy demonstrates potential as an effective treatment for plantar fasciitis, offering benefits in pain management and functional recovery. However, further high-quality randomized controlled trials are necessary to strengthen the clinical evidence and establish standardized treatment protocols.

• Asia-Pacific Journal of Business
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• v.15 no.2
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• pp.257-270
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• 2024

Purpose - The purpose of this study is to analyze the changes in the business environment, business conditions, and detailed indicators related to management of Korea's port industry companies as global supply chains have been reorganized since the shock of COVID-19 in 2020 and uncertainties in the global economy have expanded. Design/methodology/approach - This study use the business survey index of the port industry to analyze. It is a weighted BSI with the weight of workers applied. Findings - Since 2020 the BSI in the port industry including business conditions, sales unit price, profitability, and financial conditions fluctuated, but it has been generally above normal level(100). During the analysis period, the BSI for export sales was found to be better than that of domestic sales. Employment BSI was generally stable, and in the case of facility BSI, the port industry was shown to be very active in facility investment. Research implications or Originality - First, it is necessary to make manpower training systems to cultivate experts in the port industry to cope with uncertainties caused by the rapidly changing global economy and the global supply chain environment. Second, it is necessary to support for investment in technology and facilities for automation and smartization. Finally, it is necessary to establish a continuous monitoring system for the business conditions.

• Korean journal of applied entomology
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• v.54 no.2
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• pp.91-97
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• 2015

The sweetpotato whitefly, Bemisia tabaci, is the major insect pest that transmitted over 100 plant viruses including tomato yellow leaf curl virus (TYLCV) of tomato plant as virus vector in the world. In this study, cDNA library of whitefly was constructed using Gateway system for selecting target gene in order to control of B. tabaci using virus-induced gene silencing (VIGS) vector with RNAi. First of all, when using oligo d(T) rimer, the calculated titer of cDNA library was confirmed with $1.4{\times}10^4$ clones and average insert sizes was confirmed with 1 kb. However, insert size was very big for construction of cDNA. Otherwise, when using attB-N25 random primer and sonication for 6 sec, the calculated titer of cDNA library was confirmed with $1.04{\times}10^5$ clones. But mostly insert band wasn't identified on the electrophoresis, because it seemed that insert size is too small (${\leq}100bp$), also the size of identified insert was somewhat big. Finally, when using oligo d(T) primer and sonication for 1 sec, cDNA insert of whitefly was appropriated for VIGS with 300-600 bp. However, cDNA sequence included a poly A and titer was very low to $5.2{\times}10^2$ clones. It was supposed that heat shock transformation was used instead of electro-transformation. It is considered that when constructing cDNA library for using VIGS vector, (1) random primer should be used for First strand cDNA synthesis in order to remove poly A and (2) sonication for 1 sec should be performed in order to get appropriated insert size and (3) electro-transformation should be performed in order to improve transformation efficiency.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.604-609
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• 2009

Background: Recently, percutaneous cardiopulmonary support (PCPS) has been widely used to rescue patients in cardiogenic shock or cardiac arrest. However, patients with cardiopulmonary bypass (CPB) weaning failure during open heart surgery still have very poor outcomes after PCPS. We investigated clinical results and prognostic factors for patients who underwent PCPS during open heart surgery. Material and Method: From January 2005 to December 2008, 10 patients with CPB weaning failure during open heart surgery underwent PCPS using the CAPIOX emergency bypass system ($EBS^{(R)}$, Terumo Inc, Tokyo, Japan). We retrospectively reviewed the medical records of those 10 patients. Result: The average age of the patients was $60.2{\pm}16.5$ years (range, $19{\sim}77$ years). The mean supporting time was $48.7{\pm}64.7$ hours (range, $4{\sim}210$ hours). Of the 10 patients, 6(60%) were successfully weaned from the PCPS While 5 (50%) were able to be discharged from the hospital. Complications were noted in 5 patients (50%). In univariate analysis, long aortic cross clamp time during surgery, mediastinal bleeding during PCPS and high level of Troponin-I before PCPS were significant risk factors. All of the discharged patients are still surviving $34{\pm}8.6$ months (range, $23{\sim}48$ months) post-operatively. Conclusion: The use of PCPS for CPB weaning failure during open heart surgery can improve the prognosis. More experience and additional clinical studies are necessary to improve survival and decrease complications.

• Journal of Chest Surgery
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• v.43 no.1
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• pp.20-24
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• 2010

Background: Fulminant myocarditis is a rare, but life threatening condition. Its prognosis is related with proper management in the acute phase. A cardiopulmonary support device can be very useful in this phase. We report on our experiences with managing acute fulminant myocarditis with a cardiopulmonary support (CPS) device. Material and Method: We reviewed retrospectively 9 patients who had a CPS device used for their fulminant myocarditis between September, 2006 and October, 2008. A Capiox emergency bypass system (Terumo Inc, Tokyo, Japan) was percutaneously inserted in all the patients. Upon implantation, all the patients were in cardiogenic shock because of ventricular arrhythmia or severe left ventricular dysfunction. The mean left ventricular ejection fraction (EF) was $20{\pm}6%$ according to transthoracic echocardiography. Result: 3 patients died despite CPS. The CPS was bridged to a transplanted heart in one patient. The rest were successfully explanted after a mean time of $107{\pm}70$ hours of running. The mean EF after discharge was $56{\pm}7%$ without dilated cardiomyopathy. Conclusion: Fulminant myocarditis can be fatal, but its prognosis is excellent if these patients receive proper, timely treatment. A cardiopulmonary support device can be very useful in this acute period. However, the implantation and management protocol of cardiopulmonary support are not yet settled. Further study is necessary to lower the complications of cardiopulmonary support for patients with fulminant myocarditis.

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.130-140
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• 2018

Purpose: In this paper, we propose a design technique for the safety characterization grounding in the construction of the photovoltaic power generation complex which can be useful and useful as an alternative power energy source in our society. In other words, we will introduce the application of safety grounding for each application, which can improve and optimize the reliability of the internal grid from the cell module to the electric room in the photovoltaic power generation complex. Method: We analyze the earth resistivity of the soil in the solar power plant and use the computer program (CDEGS) to analyze the contact voltage and stratospheric voltage causing the electric shock, and propose the calculation and calculation method of the safety ground. In addition, we will discuss the importance of semi-permanent ground electrode selection in consideration of soil environment. Results: We could obtain the maximum and minimum value of ground resistivity for each of the three areas of the data measured by the Wenner 4 - electrode method. The measured data was substituted into the basic equation and calculated with a MATLAB computer program. That is, it can be determined that the thickness of the minimum resistance value is the most favorable soil environment for installing the ground electrode. Conclusion: Through this study, we propose a grounding system design method that can suppress the potential rise on the ground surface in the inner grid of solar power plant according to each case. However, the development of smart devices capable of accumulating big data and a monitoring system capable of real-time monitoring of seismic changes in earth resistances and grounding systems should be further studied.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.161-168
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• 2009

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at individual vehicle or platoon level through V2V and V2I communication. It is necessary to develop a new traffic management paradigm to take advantage of the ubiquitous transportation system environments. This paper proposed a preventive congestion management algorithm for uninterrupted flow, whose goal is to minimize the incident potential and maximize the productivity by maintaining traffic flow stability. The algorithm includes the following steps: Processing the raw data to produce the 3-dimension speed/flow/density profile and to produce the platoon profile and the shock wave profile, Determining the traffic state and the flow stability based on the processed data, Deciding the desirable speed the according the traffic flow state, and finally Providing the desirable speed information. It remains as further work to perform field experiments and calibrate the algorithm parameters.

• Strategy21
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• s.32
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• pp.36-70
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• 2013

Waegu(倭寇)'s invasion in the Late Goryeo(高麗) Dynasty was huge damage for Goryeo's local society. And It was shock that Goryeo government's basic foundation of rules. Invasion background of waegu for Kyeong-in-yeon(庚寅年, 1350) was Kyushyu(九州)'s political divide because of Nihon(日本) government's confusion. Waegu was huge damage for Goryeo's Jo-wun(漕運, the shipping system of grain paid as a tax) system. So, government started military response, but it was turn out a failure and had great damage. When execution of military operations failed, Goryeo government sent diplomatic delegation to request the prevent of waegu, but the invasion continued. Since waegu invasion, Goryeo was got nowhere with defence of waegu. So, some people demanded for a new understanding of the ocean defence in the government. Lee-Saek(李穡), Woo-Hyeonbo(禹玄寶), Lee-Hee(李禧) and Jung-Ji(鄭地) were representatives of a new understanding of the ocean defence. Their demands were received attention when all operations had been failed. Therefore, Goryeo government began to reorganization of the naval forces and set up a special committee of gunpowder manufacturing named Hwa-tong-do-gam(火筒都監). This administrative reform was achieved substantial results since then. In 1380, the naval battle at Jin-po(鎭浦) was a big event that first gunpowder attack the waegu. Since Jin-po, Goryeo's naval forces gain confidence. In 1389, Dae-ma-do(對馬島) was attacked by Park-Wi(朴葳). It was meant that Goryeo's naval forces had huge offense power. Goryeo's defence system was focused on a northern race before 14th century waegu's invasion. So they were neglected their ocean defence. But after military operation of waegu's invasion was failure, they focused on the ocean defence. A new understanding of the ocean defence was foundation of that. It means to us to a new understanding of the ocean defence. Now, East Asia has maritime disputes. And we have high exposure to potential threats. So, we have a new understanding of importance of the ocean defence. And we fight for 21th century's ocean threats as foundation of sense of national security.