• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.43-50
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• 2010

Recently, the Internet telephony has been used rather than the traditional telephony by many Internet users, with low cost. Session Initiation Protocol(SIP) is the standard of application layer protocol for establishment and disconnection of the session for Internet telephony. SIP mainly runs over the UDP for transport. So in case of the loss of the INVITE request message, the message is retransmitted by an appropriate timer for reliable transmission of the UDP message. Though the retransmission is useful for ensuring the reliability of SIP messages sent by the users, it may cause the overload traffic in the SIP proxy server. The overload in SIP proxy servers results in the loss of many input messages. This paper presents a non-linear overload control algorithm to resolve the overload condition of the server. we simulate our proposed algorithm using the network simulator ns-2. The simulation results show that the throughput of the server with the proposed algorithm have been improved about 12% compared to the existing linear control algorithm.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.66-74
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• 2022

To improve the solubility of β-carotene, three types of β-carotene-loaded nanocapsules were prepared using chitosan (CS) and two cross-linkers, sodium tripolyphosphate (TPP) and hyaluronic acid (HA), alone or in combination (CS-TPP, CS-TPP-HA, and CS-HA). The entrapment efficiency of all nanocapsules significantly increased with an increase in TPP and HA, with the efficiency ranging from 95% to 99%. The solubility of β-carotene was significantly improved by CS nanoencapsulation before and after lyophilization and during storage. CS/HA nanoencapsulation significantly improved (by 11-fold) the water solubility of β-carotene. In particular, CS/HA nanoencapsulation was the most effective in terms of not only the solubility of β-carotene, but also the redispersibility ratio. Therefore, CS/HA encapsulation could be useful for improving the solubility of poorly soluble active ingredients, such as β-carotene.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.1
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• pp.39-48
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• 2016

The tacit knowledge transfer cultivate the value and mount of tacit knowledge. The tacit knowledge transfer plays the most important role for improving the competitiveness of the organization. Despite the tacit knowledge transfer is very important, the research related with tacit knowledge transfer has not been actively carried out. The barriers to tacit knowledge transfer interfere with the tacit knowledge transfer. The barriers to tacit knowledge transfer are lack of understanding knowledge experts, heavy over-work, insufficient compensation, trust shortage and knowledge stickiness. In order to overcome the barrier of the tacit knowledge transfer, it is necessary to promote knowledge broker. The knowledge broker is the foundation for the tacit knowledge transfer and the critical success factor for efficient tacit knowledge transfer. However, most research related on the knowledge broker had focused on the degree, centrality and density of the knowledge network. The framework is needed to performance indicator for diagnosing the tacit knowledge transfer. Therefore, we suggest the knowledge broker framework based on the social network analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.351-351
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• 2022

현재 우리나라는 기후변화가 심화되고 강우의 불확실성이 높아지면서 자연 재해와 홍수 피해가 증가하고 있고 이에 따른 댐이나 보 운영의 고도화가 요구되고 있다. 특히 댐의 경우 다양한 원인에 의해 상류와 하류에서 홍수 피해가 빈번하게 발생하기도 하며, 방류 조절에 따라 담수 유입으로 인한 해수의 염도 변화나 수질 오염 등의 결과를 야기시킨다. 따라서 효율적인 댐 운영을 위해서는 방류량에 대한 지속적인 검증 측정이 필요하며, 유역 내 상하류 유출 특성 변화에 대한 모니터링이 요구된다. 따라서 본 연구에서는 탐진강 유역에 위치한 장흥군(별천교)관측소와 장흥군(예양교)관측소를 대상으로 가동보 운영과 식생영향, 취수영향, 공사에 따른 수위-유량관계 변화를 분석하였다. 탐진강 최상류에 위치한 장흥군(별천교)관측소의 경우 2013년 이후 유량조사가 이루어지지 않아 2021년 하류 가동보 수문 운영 조건과 수중식생 영향, 취입보 운영 조건에 따른 변화를 모니터링하고 유량측정을 실시하여 수위-유량관계의 변동성을 분석하였다. 또한 탐진강 하류에 위치한 장흥군(예양교)관측소는 기존 설치되어 있던 상하류 가동보에 대해 철거공사가 금년 진행되었으며, 이에 따른 지속적인 모니터링과 유량측정을 통해 흐름 특성 변화를 분석하였다. 추가로 저평수기와 홍수기에 장흥댐 수문 방류량에 대한 검증 측정을 수행하여 고시된 방류량과 실측된 방류량을 각각 적용하여 탐진강 유역 유출 특성 변화에 대해 분석하였다. 결과적으로 본 연구에서는 탐진강 유역 하천 내의 보 운영과 식생, 취수, 공사영향에 따른 모니터링과 유량측정을 통해 신뢰도 높은 수위-유량관계곡선식을 개발하였고, 이를 통해 생산된 유량자료는 정확도가 매우 높은 것으로 분석되었다. 또한 장흥댐 수문 방류량에 대해 실제 측정된 방류량을 유출 분석에 적용한 결과 향상된 결과를 보였으며 정상적인 상하류 관계를 나타냈다.

• Asia Marketing Journal
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• v.7 no.3
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• pp.83-104
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• 2005

This case describes Lotte Mart's practices and achievement in the aspect of social responsibilities and ethics management and its implications in retail industry. Lotte Mart set ethics management as core business objective, and establishes and operates a variety of ethics management programs for each of customer, shareholders, employees, suppliers and society. By these programs, Lotte Mart could achieve improvement in quality and price competitiveness through better partnership with supplier, get more efficiency in business through higher morale among employees, and gain improved customer loyalty through customer satisfaction.

• Composites Research
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• v.36 no.6
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• pp.422-428
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• 2023

The electrical contact resistance between the bipolar plate (BP) and the carbon felt electrode (CFE), which are in contact by the stack clamping pressure, has a great impact on the stack efficiency because of the relatively low clamping pressure of the vanadium redox flow battery (VRFB) stack. In this study, a polyethylene (PE) composite-CFE hybrid bipolar plate structure is developed through a local heat welding process to reduce such contact resistance and improve cell performance. The PE matrix of the carbon fiber composite BP is locally melted to create a direct contact structure between the carbon fibers of CFE and the carbon fibers of BP, thereby reducing the electrical contact resistance. Area specific resistance (ASR) and gas permeability are measured to evaluate the performance of the PE composite-CFE hybrid bipolar plate. In addition, an acid aging test is performed to measure stack reliability. Finally, a VFRB unit cell charge/discharge test is performed to compare and analyze the performance of the developed PE composite-CFE hybrid BP and the conventional BP.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.203-211
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• 2024

Utilizing programming languages for data visualization can enhance the efficiency and effectiveness in handling data volume, processing time, and flexibility. However, practice is required to become proficient in programming. Therefore public data-based the problem bank was developed to practice data visualization in a programming automatic assessment system. Public data were collected based on topics suggested in the curriculum and were preprocessed to make it suitable for users to visualize. The problem bank was associated with the mathematics curriculum to learn various data visualization methods. The developed problems were reviewed to expert and pilot testing, which validated the level of the questions and the potential of integrating data visualization in math education. However, feedback indicated a lack of student interest in the topics, leading us to develop additional questions using student-center data. The developed problem bank is expected to be used when students who have learned Python in primary school information gifted or middle school or higher learn data visualization.

• Smart Media Journal
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• v.13 no.8
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• pp.9-15
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• 2024

Software testing is essential in the software development process. Modified Condition / Decision Coverage (MC/DC) is a test case derivation technique that enhances the stability and reliability of software by effectively verifying complex conditions and decision structures. We propose the MCC Test Cases (MTC) generator in this study. This generator generates Multiple Condition Coverage (MCC) test cases using binary numbers to confirm the maximum coverage value of MC/DC testing. The proposed MTC generator utilizes some conditions from the Traffic Alert and Collision Avoidance System (TCAS)-II specification. It converts them into a Comma-Separated Values (CSV) file and then validates the coverage results through the VectorCAST program. So, MC/DC testing was performed using the MCC test case to confirm the maximum coverage value when performing MC/DC tests for each condition of the TCAS-II specification. This research is helpful for the verification of MC/DC test cases by confirming the maximum coverage value when performing MC/DC tests. Moreover, having more test cases increases the likelihood of discovering defects. Therefore, it can improve the efficiency of software test coverage verification, as well as the quality and stability of software.

• Journal of IKEEE
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• v.28 no.3
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• pp.369-374
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• 2024

This paper addresses the design optimization of capacitorless DRAM(one-transistor DRAM., 1T-DRAM), which has gained attention as a next-generation memory technology. To overcome the limitations of conventional capacitor-based DRAM, an asymmetric dual-gate structure is proposed to enhance retention time and overall performance. The zero-temperature coefficient (ZTC) point is set at 1.25 V to minimize performance degradation due to temperature variations. Current-voltage characteristics were analyzed at various temperatures (300K-400K), confirming stable memory operation at the ZTC point, even under temperature fluctuations. The proposed design demonstrates reliable operation at high temperatures, proving the potential for high-efficiency, highly reliable memory technology. As a result, the 1T-DRAM device can make a significant contribution to the development of next-generation memory devices.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.199-210
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• 2022

This study aimed to develop a cropping system to use limited crop-land with optimum efficiency, while considering management from farmers. To establish the cropping system involving a two-year rotation of three crops, three types of cropping system were evaluated in Suwon (Seogcheon series) and Anseong (Geumcheon series) in the middle plain area using six crops from 2018 to 2019: maize-perilla-onion, potato-sesame-garlic, and maize-sesame-onion. The crop productivity and income of the cropping systems involving food-, oilseed-, and horticultural crops were analyzed, and the optimal cropping system was reviewed. The total yield of each crop was as follows: maize 1,281 kg, potato 4,837 kg, perilla 125 kg, sesame 120 kg, onion 6,503 kg, and garlic 1,027 kg per 10a. However, in terms of gross profit, the potato was more than 3.8 times more profitable than corn, sesame was 1.8 times more profitable than perilla, and garlic was more than 2.8 times more profitable than onions. As a result, in terms of net income, the potato-sesame-garlic cropping system produced the highest income per unit area. Sesame seedlings were planted after the potato harvest, thereby solving the problem of competition between the first and last crops. Overall, this study confirmed that the potato-sesame-garlic cropping system, a two-year rotation of three crops, contributed to the improvement of upland crop productivity and farmers' income and was an overall effective cropping system.