• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.43-48
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• 2022

Although the distribution system has been structured as complicated as a mesh in the past, the connection points for each line are always kept open, so that it is operated as a radial distribution system (RDS). For RDS, the line utilization rate is determined according to the maximum load on the line, and the utilization rate is usually kept low. In addition, when a fault occurs in the RDS, a power outage of about 3 to 5 minutes occurs until the fault section is separated, and the healthy section is transferred to another line. To improve the disadvantages of the RDS, research on the construction of a networked distribution system (NDS) that linking multiple lines is in progress. Compared to the RDS, the NDS has advantages such as increased facility utilization, load leveling, self-healing, increased capacity connected to distributed generator, and resolution of terminal voltage drop. However, when a fault occurs in the network distribution system, fault current can flow in from all connected lines, and the direction of fault current varies depending on the fault point, so a high-precision fault current direction determination method and high-speed communication are required. Therefore, in this paper, we propose an accurate fault current direction determination method by comparing the peak value polarity of the fault current in the event of a fault, and a communication-based protection coordination method using this method.

• Journal of the Korea Society of Computer and Information
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• 제28권8호
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• pp.77-86
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• 2023

The background of this study lies in the increasing economic value of Korean fonts and the necessity for font development focused on small character design suitable for the mobile environment. The objective of this study is to analyze and propose strategies to improve readability on mobile screens. The research was conducted by applying eight attributes that could enhance readability according to Tim Ahrens to the design process of a Korean mobile font, adjusting Google's Noto Sans Korean for print/publishing and for small sizes. The results of the study indicate that 1. type width should be increased, 2. open counter (interior space) should be increased, 3. closed counter should be decreased, 4. font weight should be increased, 5. stroke contrast should be decreased, 6. spacing between characters should be increased. Therefore, distinct font families should be provided, differentiating between print/publishing and mobile use, as well as varying font weights and sizes, applying readability and legibility enhancement techniques for Korean fonts.

• Journal of the Korea Society of Computer and Information
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• 제19권10호
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• pp.197-205
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• 2014

This study set out to develop a logistics rationalization model to reduce logistics costs including return route costs by using open information systems that overcame the limitations of the old closed logistics systems by the corporations and applying the principle of freight car sharing among them. In recent years, information infrastructure that can be easily shared by many such as information networks, however, One of the causes of rising logistics costs is high empty transfer rates on return routes after goods are transported from the distribution center of each company to consumption sites, It is propose to promote logistic efficiency and innovation. The study especially identified a logistics rationalization plan by examining and analyzing the stages of transportation on the circulation route of a distribution system from the distribution center of a corporation to consumption sites and the empty transfer rates and their current state.

• The korean journal of orthodontics
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• 제42권4호
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• pp.218-224
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• 2012

Objective: To investigate the resistance to sliding (RS) in self-ligating and conventional ligation bracket systems at 5 different second-order bracket angulations by using low-stiffness alignment wires in a 3-bracket experimental model and to verify the performance of the main RS components in both systems when these wires are used. Methods: Interactive self-ligating brackets with closed and open slides were used for the self-ligating (SL) and conventional ligation (CL) groups, respectively; elastomeric ligatures (1 mm inner diameter) were used in the latter system. The alignment wire used was 0.014 inch heat-activated NiTi (austenitic finish temperature set at $36^{\circ}C$ by the manufacturer). A custom-made testing machine was used to measure frictional resistance. Tests were repeated 5 times at every angulation simulated. All data were analyzed statistically. Results: The RS increased significantly with increasing angulation in both SL and CL groups (p < 0.0001). However, the RS values were significantly higher at every angulation (p < 0.0001) in the CL group. Conclusions: Despite the relevance of the binding phenomenon, ligation forces predominantly affect the RS when lowstiffness alignment wires are used.

• Journal of Gastric Cancer
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• 제16권3호
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• pp.152-160
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• 2016

Purpose: Endoscopic diagnosis of gastric cancer (GC) that emerges after eradication of Helicobacter pylori may be affected by unique morphological changes. Using comprehensive endoscopic imaging, which can reveal biological alterations in gastric mucosa after eradication, previous studies demonstrated that Congo red chromoendoscopy (CRE) might clearly show an acid non-secretory area (ANA) with malignant potential, while autofluorescence imaging (AFI) without drug injection or dyeing may achieve early detection or prediction of GC. We aimed to determine whether AFI might be an alternative to CRE for identification of high-risk areas of gastric carcinogenesis after eradication. Materials and Methods: We included 27 sequential patients with metachronous GC detected during endoscopic surveillance for a mean of 82.8 months after curative endoscopic resection for primary GC and eradication. After their H. pylori infection status was evaluated by clinical interviews and $^{13}C$-urea breath tests, the consistency in the extension of corpus atrophy (e.g., open-type or closed-type atrophy) between AFI and CRE was investigated as a primary endpoint. Results: Inconsistencies in atrophic extension between AFI and CRE were observed in 6 of 27 patients, although CRE revealed all GC cases in the ANA. Interobserver and intraobserver agreements in the evaluation of atrophic extension by AFI were significantly less than those for CRE. Conclusions: We demonstrated that AFI findings might be less reliable for the evaluation of gastric mucosa with malignant potential after eradication than CRE findings. Therefore, special attention should be paid when we clinically evaluate AFI findings of background gastric mucosa after eradication (University Hospital Medical Information Network Center registration number: UMIN000020849).

• Journal of Radiation Protection and Research
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• 제11권2호
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• pp.130-138
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• 1986

A study on the measurement of alpha activity in ground air has been carried out using CA 80-15 and LR 115-1 cellulose nitrate nuclear track detectors. The detection efficiency of the detectors were determined by making use of an $^{241}Am$ alpha source of $0.1{\mu}Ci$ in activity under a known geometrical arrangement. For the field measurement of alpha activity of emanated radon and its progeny in ground air two different radon cups were installed for a certain period of time in two neighbouring ground holes of about 15 cm in diameter and 45 cm in depth. Of the two radon cups one kept closed space during the detecting period, while the other kept open space with a hole enabling the air to ventilate. The etched tracks were read out by a microscope and the results obtained through statistical analysis were evaluated in terms of alpha activity per unit volume of air.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제12권6호
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• pp.207-213
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• 2012

With development of IT technology, B2C Social Commerce makes the change from closed type of transaction to the form of an open trading. Also by dramatically reducing the intermediate distribution and removing distribution costs, it provides goods at unbeatable prices to consumers. Depending on the flow of the times, the business-to-business struggles with the difficulty of PRM management and fast promotion of new products. Therefore, it is required B2B Social Commerce, new platform that can collect distribution and consumption firms in one place which is similar to B2C Social Commerce. Unlike the case of B2C social commerce, B2B Social Commerce should have an essential element, Installment payment system to pay over the period without purchase in accordance with the payment paid as a lump sum. B2B Social Commerce model which is introduced in this study will provide the solution of B2B transaction problems, opening up new markets and bring the expansion of the electronic market.

• YAKHAK HOEJI
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• 제49권5호
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• pp.437-442
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• 2005

The purpose of this study was to characterize the putative anxiolytic-like effects of phenylpropanoids using the elevated plus maze (EPM) test in mice. Cinnamic acid, p-coumaric acid, caffeic acid and ferulic acid were orally administered to male ICR mice, 1 h before behavioral evaluation in an EPM, respectively. Control mice were treated with an equal volume of vehicle, and positive control mice diazepam (1 mg/kg). A single treatment with phenylpropanoids (at 8 mg/kg) significantly increased time-spent and arm entries into the open arms of the EPM, and decreased time-spent and arm entries into the closed arms of the EPM versus control (P<0.05). However, no changes in the locomotor activity and myorelaxant effect were seen in any group versus the saline control. These results suggest that phenylpropanoids may be an effective anx-iolytic agent.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제11권5호
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• pp.151-157
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• 2011

This study analyzed the posture balance of time variation for exercising body a period of time. Posture balance measured output values for the posture balance system of body moving in the multi-parameter. Posture moving variation had three methods such as open and closed eye, head moving and upper body moving. There were checked a parameter that measured vision, vestibular, somatosensory, CNS. This system was evaluated a data through the stability. This system has catched a signal for physical condition of body data such as a data acquisition system, data signal processing and feedback system. The output signal was generated Fourier analysis that using frequency of 0.1Hz, 0.1-0.5Hz, 0.5-1Hz and 1Hz over. The posture balance system will be used to support assessment for body moving the posture balance of time variation. It was expected to monitor a physical parameter for health verification system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제32권4호
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• pp.242-251
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• 2020

In this study, the extraction efficiency and reflection coefficient by a two-dimensional OWC (Oscillating Water Column) WEC (wave energy converter) installed in front of a seawall was investigated for regular/irregular waves. The matched eigenfunction expansion method (MEEM) based on the linear potential theory was applied as an analytical tool. The diffraction problem by the incident wave in the open-chamber and the radiation problem by the oscillating pressure in the closed-chamber were solved to obtain the volume fluxes at the internal free-surface. Applying the volume fluxes into the continuity equation for the airflow in a chamber, we got the oscillating air pressure. The maximum extracted power and corresponding reflection coefficient were determined at the optimal turbine coefficient that maximizes the extracted power. OWC device designed for a high extracted efficiency simultaneously contributes to reduce reflected waves.