• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.740-754
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• 2015

This paper focuses on the reverse blocking busbar protection scheme with aim to improve the speed of its operation and at the same time to increase operational reliability, flexibility and stability of the protection during external and internal faults by implementation of the extended functionality provided by the IEC61850 standard-based protective Intelligent Electronic Devices (IEDs). The practical implementation of the scheme by the use of IEC 61850 standard communication protocol is investigated. The proposed scheme is designed for a radial type of a distribution network and is modeled and simulated in the DigSILENT software environment for various faults on the busbar and its outgoing feeders. A laboratory test bench is built using three ABB IEDs 670 series that are compliant with the IEC 61850 standard, CMC 356 Omicron test injection device, PC, MOXA switch, and a DC power supplier. Two types of the reverse blocking signals between the IEDs in the test bench are considered: hard wired and Ethernet communication by using IEC 61850 standard GOOSE messages. Comparative experimental study of the operational trip response speeds of the two implementations for various traffic conditions of the communication network shows that the performance of the protection scheme for the case of Ethernet IEC 61850 standard-based communication is better.

• 한국인터넷방송통신학회논문지
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• 제18권4호
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• pp.79-83
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• 2018

EMI 스프레이 코팅막의 차폐효과(Shield Effectiveness, SE)를 측정하기 위한 정확한 방법을 제안하였다. 고주파 시뮬레이션을 한 후에 원형 동축 표준 측정기를 제작하였다. 원형 동축 표준 측정기에 삽입하기 위하여 EMI 스프레이 코팅막의 시료를 가공하였다. 차폐효과 측정을 위한 측정기는 에이질런트 8722ES 벡터 네트워크 분석기를 이용하였다. 이러한 측정기와 측정시료의 구성으로 구리와 은의 혼합 스프레이 코팅 시료의 정확한 차폐효과를 측정하였다. 동박 시료의 차폐효과는 70 dB로 측정되었고, 구리와 은의 혼합 스프레이 코팅 시료의 차폐효과는 60 dB로 측정되었다. 이와 같은 측정 결과로 원형 동축 표준 측정기의 신뢰성을 확인하였다.

• 한국통신학회논문지
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• 제25권3B호
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• pp.504-509
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• 2000

This paper presents a noble operation and maintenance system for the optical subscriber loops and its feasibility through several experiments. In this system, a broadband CW (Continuous Wave) light source I used as monitoring of testing signals. and a FGF(Fiber Grating Filter) of which reflective wavelength is independent, is inserted somewhere in each subscriber loop for the reflection of monitoring of testing signals. The propose of the system is quick decision. whether the loop is just fault or not. rather than detailed information of loop state. At present, most of operation and maintenance system for the optical subscriber loops adopts OTDR(optical time domain reflectometer) for testing function. the OTDR is useful for detailed test, but not adequate for simple test because of long testing time . And it is difficult to test PON network by using general OTDR that has a single-wavelength light source. Compared to using OTDR, the proposed system can afford to shorten testing time and to test PON network. Moreover, we can cut down the system cost by simplifying circuits of the optical light sources. Our results show that the proposed system operates well according to the purpose mentioned above.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.23-28
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• 2022

The present study has been conducted to evaluate the experience in using peer-to-peer platforms and immersive technologies in the training of future masters of pharmacy from the Pharmaceutical Faculty of Bogomolets National Medical University, Ukraine. The selected participants were given the pre- and post-test containing multiple choice questions to assess the effectiveness of immersive technologies. Further, a self-designed structured questionnaire contained 10 questions with 5 options was delivered to consented participants through email and WhatsApp. The results of test presented that students attained an average of 26% in their pre-test while the average attained score post-test was 74% that showed a significant improvement with peer-to-peer platforms and virtual reality technology. The results of survey questions also showed an overall 86.73% satisfaction for the use of peer-to-peer platforms and virtual reality technology in the training of future masters of pharmacy. These results demonstrated that 90.81% showed agreement that they gained a high level of confidence through peer-to-peer platforms and virtual reality to handle patients in clinical practice. It can be concluded that participants of this study showed a strong agreement with positive experience in using peer-to-peer platforms and virtual reality technology in the training of future masters of pharmacy in medical lyceum.

• International Journal of Computer Science & Network Security
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• 제22권5호
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• pp.149-153
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• 2022

This study examines the effect of using interactive electronic models to teach mathematical concepts on students' achievement in the linear algebra course at university. The field sample consisted of 200 students divided into two equal groups, an experimental group of 100 students and a control group of 100 students. The researcher used an achievement test in some mathematical concepts related to linear algebra. The results of the study showed that there were statistically significant differences (0.05) between the average achievement scores of the experimental and control groups in the post application of the achievement test, in favor of the experimental group. The size of the influence of the independent factor on the results of the study, which is "interactive electronic forms", on the dependent factor, which is the students' academic achievement in the prepared test, had a very large effect. Also, the results of the study showed that there were statistically significant differences (0.05) between the mean scores of the experimental group in the pre and post applications of the achievement test, in favor of the post application. The researcher recommended the use of interactive electronic models in teaching mathematical concepts at the university level and diversifying the strategies of teaching mathematics, using technology to attract learners and raise their academic achievement.

• 디지털융복합연구
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• 제15권6호
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• pp.391-398
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• 2017

본 논문에서는 "퍼지 컨트롤 언어를 이용한 공격 특징 선택기반 네트워크 침입탐지 시스템"[1]과 "RNN을 이용한 공격 분류를 위한 지능형 침입탐지 시스템 모델"[2]의 성능을 비교 하였다. 이 논문에서는 KDD CUP 99 데이터 셋[3]을 이용하여 두 기법의 침입 탐지 성능을 비교하였다. KDD CUP 99 데이터 셋에는 훈련을 위한 데이터 셋과 훈련을 통해 기존의 침입을 탐지 할 수 있는 테스트 데이터 셋이 있다. 또한 훈련 데이터 및 테스트 데이터에 존재 하지 않는 침입의 유형을 탐지할 수 있는가를 테스트 할 수 있는 데이터도 존재한다. 훈련 및 테스트 데이터에서 좋은 침입탐지 성능을 보이는 두 개의 논문을 비교하였다. 비교한 결과 존재하는 침입을 탐지 하는 성능은 우수하지만 기존에 존재하지 않는 침입을 탐지 하는 성능은 부족한 부분이 있다. 공격 유형 중 DoS, Probe, R2L는 퍼지를 이용하는 것이 탐지율이 높았고, U2L은 RNN을 이용하는 것이 탐지율이 높았다.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• 전기전자학회논문지
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• 제27권4호
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• pp.668-678
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• 2023

FlexRay는 차량 내 네트워크(In-Vehicle Network)로 최대 2개의 채널로 각 채널당 최대 10Mbps 전송 속도를 가진다. FlexRay는 TDMA(Time Division Multiple Access)와 FTDMA(Flexible Time division Multiple Access) 방식을 사용하여 효율적으로 데이터를 전송하면서도 실시간 통신을 보장하기 때문에 파워트레인 등 안전성이 필수적인 차량 모듈의 실시간 전자 제어에 사용된다. 본 논문에서는 ISO 17458 표준과 FlexRay 컨소시엄 문서를 바탕으로 FlexRay의 프로토콜(Protocol), 시간 계층(Time Hierarchy), 메시지 프레임(Message Frame), 커뮤니케이션 컨트롤러(Communication Controller), 적합성 시험(Conformance Test)에 대해 자세히 설명한다.

• 디지털콘텐츠학회 논문지
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• 제3권1호
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• pp.101-111
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• 2002

인터넷을 중심으로 최근의 네트워크의 발전은 데이터 전송량의 범위를 멀티미디어 정보까지 확대시킴에 따라 멀티미디어 서비스를 보장하기 위해서 기존 인터넷의 Best Effort service에서 제공하지 못하는 end-to-end QoS(Quality of Service)의 제공이 필수적이다. 이를 위해 일정한 수준의 대역폭, 전송지연, 지연변이, 데이터 손실률 등의 network parameter 뿐만 아니라 시스템 내에서도 일정 수준의 CPU time 이나 메모리를 보장해 주어야 한다. 이에 따라 한정된 자원 안에서 멀티미디어 데이터를 분산시켜 네트워크 자원을 효율적으로 관리하기 위해 네트워크 자원 상황에 따라 적절하게 서비스 레벨을 조절하는 QoS 기반 통신 미들웨어의 개발이 시급하다. 또한 네트워크 시스템 및 application 개발자의 입장에서는 이를 구현하기 위해 실제 사용자가 느끼고 평가하게 되는 QoS의 객관적이고 사실적인 측정이 절실히 요구된다. 이를 위해 ATM 망상에서 보다 편리한 QoS 측정장치를 개발하고 또한 이러한 측정기술을 바탕으로 데이터를 추출하여 향상된 QoS를 제공하기 위한 개선된 미들웨어의 실질적인 메커니즘 개발과 검증에 적용한다.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.335-343
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• 2021

The study aimed to elucidate how to design a learning environment on the premise of micro-learning (ML) and investigate its impact on website designing skills and achievement motivation among secondary school students. Adopting the experimental approach, data were collected through an achievement test, a product evaluation form, and a test to gauge motivation for achievement. The sample was divided into two experimental groups. Results revealed statistically significant differences at 0.05≥α between the mean scores of the two groups that experienced ML, irrespective of the two modes of presenting the video in the pre-test and post-test, as for the test of websites design skills, product evaluation form, and achievement motivation test. Besides, there have been statistically significant differences at 0.05≥α between the mean scores of the first experimental group that had exposure to ML using the split-video presentation style and the scores of the second experimental group that underwent ML using continuous video presentation style in the post cognitive test of website design and management skills in favor of the group that had segmented-video-presentation ML. Another salient finding is the nonexistence of significant differences at 0.05≥α between the mean scores of the first experimental group that underwent segmented-video-presentation ML and the grades of the second experimental group that received ML with continuous video presentation style in the post-application of the product scorecard of websites designing skills and the motivation test. In light of these salient findings, the study recommended using ML in teaching computer courses at different educational stages in Saudi Arabia, training computer and information technology teachers to harness ML in their teaching and using ML in designing courses at all levels of education.