• Title/Summary/Keyword: DEA method

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Application of 'Metaverse' teaching method, problems and usage plan ('메타버스' 교수법 적용, 문제점 및 활용방안)

  • Cho, Woo-Hong;Jang, Young-Eun;Byon, Kil-Hee;Choi, Dea-Hun;Kim, Mee-Kyung
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2022.07a
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    • pp.361-363
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    • 2022
  • 본 연구의 목적은 메타버스 교수법 적용을 통해 문제점을 파악하고 활용방안을 모색하고자 하였다. 본 연구의 교수법을 효율적으로 달성하기 위해 각각 전공이 다른 교수자가 참여하여 학습법을 공유하였다. 대부분 메타버스 활용으로 흥미로운 학습법이 이루어진 반면에 다양한 문제점도 나타났다. 활용방안으로 게임, 토론, 대화 등을 통해 사전에 충분히 숙달될 수 있도록 하고, 정규수업이 아닌 비정규 교과목에서 우선 적용, 아바타 꾸미기 활용으로 보다 즐겁게 수업 참여 유도, 가상현실속에서 예의범절 지키기 등 학습 환경 이해, 학생들의 가상공간을 통해 자신들의 언어로 수업을 이끌어 흥미 유발, 젭 스페이스에서 나만의 강의실 만들기, 친구와 대화 및 상호작용 시행, 이론 교과목 수업 메타버스 플랫폼을 활용, 모의토론 및 발표 자유롭게 유도, 자신만의 케릭터 꾸미기, 진로코칭 및 상담 적용, 수업 종료후 학생만의 추가 활동 유도 등 활용방안이 제시되었다.

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An Emergency Message Propagation Method with Stem and Branch Structure for Vehicle Safety Communication (차량안전통신을 위한 줄기와 가지 구조를 이용한 긴급 메시지 전파 방법)

  • Yu, Suk-Dea;Cho, Gi-Hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2A
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    • pp.203-212
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    • 2007
  • An advanced vehicle safety system can be constructed by exchanging danger-related information ,such as urgency stop, traffic accident, obstacle, and car trouble, among the vehicles. However, because network topology changes rapidly and frequently due to the mobility of vehicles, it is impossible to configure the network for information forwarding in this environment. In the most of vehicle safety communication applications, an emergency message is propagated in a form of broadcasting. The simple broadcasting causes a lot of problems in terms of efficiency due to multi-hop area and radio collision problem. This paper proposes a method of selective message forwarding with stem and branch structure for propagating the emergency messages. However, the proposed method raise the efficiency of message transmission with the selective forwarding based on the priority assignment as its location. We analyze and evaluate the performance by comparing the proposed scheme with other schemes that are presented in the paper.

An Inter-Vehicle Emergency Message Propagation Method with Vehicle Equivalent Group (차량동위그룹을 이용한 차량 간 긴급 메시지 전파 방법)

  • Yu, Suk-Dea;Cho, Gi-Hwan
    • Journal of KIISE:Information Networking
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    • v.34 no.5
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    • pp.340-347
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    • 2007
  • Vehicle safety service can be effectively achieved with inter-vehicle communication technologies, in which moving vehicles transmit a safety related urgency information such as traffic accidents, sudden stops, obstacle appearance etc. They usually utilize a broadcast of message propagation method because the communicating vehicles are not known each other. The pure broadcasting scheme does not satisfy the requirements of vehicle safety communication service due to the transmission delay with frequent message collisions. To resolve this problem, this paper presents a group based propagation method for the multi-hop transmission, in order to deliver an urgency message to the reasonable size of vehicle troop. A group header is elected in considering of the position information of vehicles and radio transmission range. And a vehicle equivalent group is formed with the header. With benefits of the group based transmission, it is possible to minimize the unnecessary transmission and the possibility of message collisions. Simulation results show that the message propagation performance is so stable regardless of vehicle's congestion degree.

A Method of Enhancing Security of Internet Banking Service using Contents-Based CAPTCHA (콘텐츠 기반 캡차를 이용한 인터넷 뱅킹 서비스의 보안성 향상 기법)

  • Lee, Sang-Ho;Kim, Sung-Ho;Kang, Jeon-Il;Byun, Je-Sung;Nyang, Dea-Hun;Lee, Kyung-Hee
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.23 no.4
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    • pp.571-583
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    • 2013
  • Internet banking service has a advantage that is unrestricted by time. If automated programs are able to attack Internet banking services, a number of accounts can be attacked at the same time and as a result, damage will be considerably increased. To cope with such attacks, two methods, VPS and MS watermark, were introduced by Arcot and MS respectively. The methods use text-based CAPTCHAs in the process of transfer approval to distinguish automated programs from legal human users. In this paper, we point out the security threats of the methods when those are applied to Internet banking services. Especially, we consider the attack that are performed by extract specific string from text-based CAPTCHAs and it's countermeasure. Also we suggest a method of enhancing security of internet banking services. Our method is based on contents-based CAPTCHAs that are consist of known transfer information between user and server.

Smart Phone Copyright Violation and Forensic Apply Method (Smart Phone 저작권 위반과 포렌식 적용 방안)

  • Yi, Jeong-Hoon;Park, Dea-Woo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.11
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    • pp.2491-2496
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    • 2010
  • Smart Phone with domestic demand increasing rapidly, the utilization of multimedia services have become diverse. Smart Phone users use the copyrighted multimedia contents illegally from hacking their Smart Phone with Jail Breaking and Rooting. Legal issues according to the Korea-U.S. FTA. and high relevance with crime as mobile communication terminal, the utilization of created and saved digital evidence is high, the mobile forensic evidence study is required. This paper studied method and notice of legal seizure and search assuming the Smart Phone copyright violation. Research the status of Smart Phone copyright violation and related violation by category as broadcasting, movies, music, e-book etc. Research the method of submit a report to the court by applying techniques to forensic. The results of this research will contribute to the provide of Smart Phone crime evidence and mobile forensic technology.

Study on the Tree Height Using Unmanned Aerial Photogrammetry Method (무인항공사진측량 기법을 적용한 수고 산정 연구)

  • BANG, Dea-Sick;LEE, Dong-Gook;YANG, Sung-Ryong;LEE, Hyun-Jik
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.3
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    • pp.35-47
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    • 2018
  • Tree height is information that is used as a parameter for variety of tasks related to forests. Specifically, customized topics related to forests such as afforestation map are also used for production. In order to calculate tree height information, a field survey or drawing was using aerial photographs. However, there is a problem that is costing a lot of time and money. Therefore, it was suggested to calculate tree height using aerial photographs taken every two years. Thus, the method for calculating tree heights was validated by unmanned aerial photogrammetry, and tree heights were calculated using outputs generated by unmanned aerial photogrammetry applied to the unmanned aerial photograph and Aerial photograph DB. The comparison of calculated tree heights shows that the measures proposed in this study are efficient. and We expect to improve the usability of aerial photographs DB.

Direction Sensor Design for Reducing Perforation Risk in Endoscopy (천공부작용 해소용 내시경 Direction Sensor 설계)

  • Kang, Sang-man;Park, Dea-woo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.4
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    • pp.836-845
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    • 2017
  • Due to the development of endoscopic technology, endoscopic diagnosis and procedures have been actively performed. However, due to the increase in colorectal cancer and the effect of government's early cancer screening project, the number of endoscopic diagnosis and procedures has increased, thus medical accidents such as perforation and bleeding are increasing. Therefore, efforts to reduce such medical accidents are needed. In this paper, we propose a method to provide the direction information of the endoscope and the force applied to the probe in real time. We also propose and evaluate an interpolated complementary filter considering the very slow movement of the endoscope probe. The proposed interpolated complementary filter showed 34.6% and 27.6% performance improvement. The expected user interface for applying the proposed method to the endoscopic system is also presented. This shows that the proposed method is applicable to endoscopy system.

Synthesis of (Ni,Mg)Al2O4 Ceramic Nano Pigment by a Polymerized Complex Method (착체중합법을 이용한 (Ni,Mg)Al2O4 Cyan 나노 무기안료 합성)

  • Son, Bo-Ram;Yoon, Dea-Ho;Han, Kyu-Sung;Cho, Woo-Suk;Hwang, Kwang-Taek;Kim, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.50 no.3
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    • pp.195-200
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    • 2013
  • Here, we report preparation of cyan ceramic nano-pigment for inkjet printing and the Ni substitutional effects on the cyan color. $MgAl_2O_4$ was selected as the crystalline host network for the synthesis of nickel-based cyan ceramic nano-pigments. Various compositions of $Ni_xMg_{1-x}Al_2O_4$ ($0{\leq}x{\leq}1$) powders were prepared using the polymerized complex method. The powder was then preheated at $400^{\circ}C$ for 5 h and finally calcined at $1000^{\circ}C$ for 5 h. XRD patterns of $Ni_xMg_{1-x}Al_2O_4$ showed a single phase of the spinel structure in all the compositions. The particle sizes ranged from 20 to 50 nm in TEM observations. The characteristics of the color tones of $Ni_xMg_{1-x}Al_2O_4$ were analyzed by UV-Visible spectroscopy and CIE $L^*a^*b^*$ measurement. CIE $L^*a^*b^*$ measurement results indicate that the pigment color changes from light cyan to deep cyan due to the decrease of the $a^*$ and $b^*$ values with an increase of an Ni substitutional amount. In addition, the thermal stability and the binding nature of $Ni_xMg_{1-x}Al_2O_4$ are also discussed using TG-DSC and FT-IR results respectively.

Earth pressure of vertical shaft considering arching effect in layered soils (다층지반에서의 아칭현상에 의한 수직갱 토압)

  • Lee, In-Mo;Moon, Hong-Pyo;Lee, Dea-Su;Kim, Kyung-Ryeol;Cho, Man-Sub
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.1
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    • pp.49-62
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    • 2007
  • A new earth pressure equation acting on the vertical shafts in cohesionless soils has been proposed by modifying the equations proposed by others. In order to verify the modified equation, model tests which can control uniform wall displacement with depth to radial direction were conducted. Model tests were performed with three different wall friction angles and two different relative densities. The measured values were larger than estimated values when assuming $\lambda=1$ ; smaller than those when assuming $\lambda=1-sin\phi$. The parameter, $\lambda$ is the ratio of tangential stress to vertical stress and is the most critical value in proposed equation. A method which can estimate the earth pressure on vertical shafts in layered soils is also proposed by reasonably assuming the failure surface of layered soils and using the modified equation. In order to verify the proposed method, in-situ measurement data have been collected from the three in-situ vertical shafts installed in layered soils. Most of earth pressures converted from measured data match reasonably well with estimated values using proposed method.

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Performance Improvement of FMT-OFDM System in Underwater Channel Environment (수중 채널환경에서 FMT-OFDM 시스템의 성능 향상을 위한 연구)

  • Kim, Min-sang;Ko, Hak-lim;Kim, Seung-geun;Cho, Dea-young;Im, Tae-ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.3
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    • pp.365-370
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    • 2016
  • Recently, There are increasing number of studies that apply multi-carrier method, a land mobile communication method, to underwater channel environment in order to enhance the performance of underwater communication. Therefore, in this paper, in order to design a new system with improved communication performance compared to the multi-carrier method in underwater communication, we present that the RS(Resource Spreading) FMT-OFDM system has a diversity and repetition effect from resource spreading. Moreover, we verify the performance of RS FMT-OFDM system and existing FMT-OFDM system through simulations after modeling communication channels and setting the system parameter based on the data measured from the real sea. Our result indicate that, compared to the existing FMT-OFDM system, there has been an improvement in communication performance by 12dB based on BER $10^{-3}$ we also discovered that communication performance improves as the resource spreading rate increases.