• Title/Summary/Keyword: Computer-networks

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A Study on the Operation of Multi-Beam Antenna for Airborne Relay UAV considering the Characteristics of Aircraft (비행체의 특징을 고려한 공중중계 무인기 다중빔 안테나 운용 방안)

  • Park, Sangjun;Lee, Wonwoo;Kim, Yongchul;Kim, Junseob;Jo, Ohyun
    • Journal of Convergence for Information Technology
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    • v.11 no.4
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    • pp.26-34
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    • 2021
  • In the era of the Fourth Industrial Revolution, the future battlefield will carry out multi-area operations with hyper-connected, high-speed and mobile systems. In order to prepare for changes in the future, the Korean military intends to develop various weapons systems and form a multi-layer tactical network to support On The Move communication. However, current tactical networks are limited in support of On The Move communications. In other words, the operation of multi-beam antennas is necessary to efficiently construct a multi-layer tactical network in future warfare. Therefore, in this paper, we look at the need for multi-beam antennas through the operational scenario of a multi-layer tactical network. In addition, based on development consideration factors, features of rotary-wing and fixed-wing aircraft, we present the location and operation of airborne relay drone installations of multi-beam antennas.

A New Dual Connective Network Resource Allocation Scheme Using Two Bargaining Solution (이중 협상 해법을 이용한 새로운 다중 접속 네트워크에서 자원 할당 기법)

  • Chon, Woo Sun;Kim, Sung Wook
    • KIPS Transactions on Computer and Communication Systems
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    • v.10 no.8
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    • pp.215-222
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    • 2021
  • In order to alleviate the limited resource problem and interference problem in cellular networks, the dual connectivity technology has been introduced with the cooperation of small cell base stations. In this paper, we design a new efficient and fair resource allocation scheme for the dual connectivity technology. Based on two different bargaining solutions - Generalizing Tempered Aspiration bargaining solution and Gupta and Livne bargaining solution, we develop a two-stage radio resource allocation method. At the first stage, radio resource is divided into two groups, such as real-time and non-real-time data services, by using the Generalizing Tempered Aspiration bargaining solution. At the second stage, the minimum request processing speeds for users in both groups are guaranteed by using the Gupta and Livne bargaining solution. These two-step approach can allocate the 5G radio resource sequentially while maximizing the network system performance. Finally, the performance evaluation confirms that the proposed scheme can get a better performance than other existing protocols in terms of overall system throughput, fairness, and communication failure rate according to an increase in service requests.

A Case Study of Spatial CAD Education in Blended Learning Environment (혼합형 학습(Blended Learning) 환경에서의 공간디자인 CAD 수업 사례연구)

  • Hwang, Ji Hyoun;Lim, Haewon
    • The Journal of the Korea Contents Association
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    • v.21 no.10
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    • pp.115-126
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    • 2021
  • The purpose of this study is to closely analyze the case of blended-learning in order to provide a diverse and flexible learning environment while maintaining the nature of face-to-face classes, and to identify the learning environment that supports blended-learning in each class step and the educational experience of students. The experience and satisfaction of blended learning were investigated in various ways: course evaluation, LMS activity evaluation, and questionnaire before and after the class. As a result, the blended-learning is better than the traditional face-to-face classes, in providing real-time feedback, opportunities for various interactions, and textual conversations, anytime and anywhere. In addition, as a result of the preliminary survey, as a measure to solve the opinion that concentration was reduced due to problems such as networks and felt uncomfortable in the communication part, the theory and lectures of the design practice class were conducted non-face-to-face. The individual Q&A and feedback were conducted face-to-face and non-face-to-face. As a result of the follow-up survey, it was found that concentration and efficiency could be improved. This opens up possibilities for active use of the online environment in design practice classes.

A Study on Analysis and Development of Education Program in Information Security Major (대학의 정보보호 관련학과 교육과정분석과 모델개발에 관한 연구)

  • 양정모;이옥연;이형우;하재철;유승재;이민섭
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.13 no.3
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    • pp.17-26
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    • 2003
  • Recently, as the internet is widespread rapidly among the public, people can use a variety of useful information services through the internet. Accordingly, the protection of information supplied by computer networks 5 has become a matter of primary concern on the whole world. To accede to the realistic demands, it has been worked out some countermeasures to cultivate the experts in information security by the government and many educational facilities. Already the government authority has carried out the each kinds of concerning projects under the framed a policy, Five-Year Development Plan for Information Security Technology. Also, many domestic universities perceives such an international trend, and so they frame their plans to train for the experts in this field, including to found a department with respect to the information security. They are ready to execute their tangible works, such as establishment of educational goal, development of teaching materials, planning curriculum, construction of laboratories and ensuring instructors. Moreover, such universities lead to their students who want to be information security experts to get the fundamental knowledge to lay the foundation for acquiring the information security technology in their bachelor course. In this note, we survey and analyze the curricula of newly-established or member-extended departments with respect to information security fields of some leading universities in the inside and outside of the country, and in conclusion, we propose the effective model of curriculum and educational goal to train the students for the information security experts.

Efficient RSA-Based PAKE Procotol for Low-Power Devices (저전력 장비에 적합한 효율적인 RSA 기반의 PAKE 프로토콜)

  • Lee, Se-Won;Youn, Taek-Young;Park, Yung-Ho;Hong, Seok-Hie
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.19 no.6
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    • pp.23-35
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    • 2009
  • Password-Authenticated Key Exchange (PAKE) Protocol is a useful tool for secure communication conducted over open networks without sharing a common secret key or assuming the existence of the public key infrastructure (PKI). It seems difficult to design efficient PAKE protocols using RSA, and thus many PAKE protocols are designed based on the Diffie-Hellman key exchange (DH-PAKE). Therefore it is important to design an efficient PAKE based on RSA function since the function is suitable for designing a PAKE protocol for imbalanced communication environment. In this paper, we propose a computationally-efficient key exchange protocol based on the RSA function that is suitable for low-power devices in imbalanced environment. Our protocol is more efficient than previous RSA-PAKE protocols, required theoretical computation and experiment time in the same environment. Our protocol can provide that it is more 84% efficiency key exchange than secure and the most efficient RSA-PAKE protocol CEPEK. We can improve the performance of our protocol by computing some costly operations in offline step. We prove the security of our protocol under firmly formalized security model in the random oracle model.

High Quality Video Streaming System in Ultra-Low Latency over 5G-MEC (5G-MEC 기반 초저지연 고화질 영상 전송 시스템)

  • Kim, Jeongseok;Lee, Jaeho
    • KIPS Transactions on Computer and Communication Systems
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    • v.10 no.2
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    • pp.29-38
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    • 2021
  • The Internet including mobile networks is developing to overcoming the limitation of physical distance and providing or acquiring information from remote locations. However, the systems that use video as primary information require higher bandwidth for recognizing the situation in remote places more accurately through high-quality video as well as lower latency for faster interaction between devices and users. The emergence of the 5th generation mobile network provides features such as high bandwidth and precise location recognition that were not experienced in previous-generation technologies. In addition, the Mobile Edge Computing that minimizes network latency in the mobile network requires a change in the traditional system architecture that was composed of the existing smart device and high availability server system. However, even with 5G and MEC, since there is a limit to overcome the mobile network state fluctuations only by enhancing the network infrastructure, this study proposes a high-definition video streaming system in ultra-low latency based on the SRT protocol that provides Forward Error Correction and Fast Retransmission. The proposed system shows how to deploy software components that are developed in consideration of the nature of 5G and MEC to achieve sub-1 second latency for 4K real-time video streaming. In the last of this paper, we analyze the most significant factor in the entire video transmission process to achieve the lowest possible latency.

Evaluation of Electromagnetic Pulse Shielding Effectiveness and Bonding Performance of Inorganic Paint based on Carbon Material (탄소재료 기반 무기계 도료의 전자파 차폐성능 및 부착성능 평가)

  • Jang, Kyong-Pil;Kim, Sang-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.801-807
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    • 2021
  • In various industrial fields and infrastructure based on electronic components, such as communication equipment, transportation, computer networks, and military equipment, the need for electromagnetic pulse shielding has increased. Two methods for applying electromagnetic pulse shielding are effective. The first is construction using shielding materials, such as shielding concrete, shielding doors, and shielding windows. The other is coating shielding paints on non-shielding structures. Electromagnetic pulse shielding paints are made using conductive materials, such as carbon nanotubes, graphite, carbon black, and carbon fiber. In this paint, electromagnetic pulse shielding performance is added to the commonly used water-based paint. In this study, the shielding effectiveness and bonding performance of paints using conductive graphite and carbon black as shielding materials were evaluated to develop electromagnetic pulse shielding inorganic paints. The shielding effectiveness and bonding performance were evaluated by applying six mixtures composed of different kinds and amounts of shielding material. The mixture of conductive graphite and carbon black at a weight ratio of 1:0.2 was the most effective in shielding as 33.6 dB. Furthermore, the mixture produced using conductive graphite only showed the highest bonding performance of 1.06 MPa.

Development of a DEVS Simulator for Electronic Warfare Effectiveness Analysis of SEAD Mission under Jamming Attacks (대공제압(SEAD) 임무에서의 전자전 효과도 분석을 위한 DEVS기반 시뮬레이터 개발)

  • Song, Hae Sang;Koo, Jung;Kim, Tag Gon;Choi, Young Hoon;Park, Kyung Tae;Shin, Dong Cho
    • Journal of the Korea Society for Simulation
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    • v.29 no.4
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    • pp.33-46
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    • 2020
  • The purpose of Electronic warfare is to disturbe, neutralize, attack, and destroy the opponent's electronic warfare weapon system or equipment. Suppression of Enemy Air Defense (SEAD) mission is aimed at incapacitating, destroying, or temporarily deteriorating air defense networks such as enemy surface-to-air missiles (SAMs), which is a representative mission supported by electronic warfare. This paper develops a simulator for analyzing the effectiveness of SEAD missions under electronic warfare support using C++ language based on the DEVS (Discrete Event Systems Specification) model, the usefulness of which has been proved through case analysis with examples. The SEAD mission of the friendly forces is carried out in parallel with SSJ (Self Screening Jamming) electronic warfare under the support of SOJ (Stand Off Jamming) electronic warfare. The mission is assumed to be done after penetrating into the enemy area and firing HARM (High Speed Anti Radiation Missile). SAM response is assumed to comply mission under the degraded performance due to the electronic interference of the friendly SSJ and SOJ. The developed simulator allows various combinations of electronic warfare equipment specifications (parameters) and operational tactics (parameters or algorithms) to be input for the purpose of analysis of the effect of these combinations on the mission effectiveness.

A New Incentive Based Bandwidth Allocation Scheme For Cooperative Non-Orthogonal Multiple Access (협력 비직교 다중 접속 네트워크에서 새로운 인센티브 기반 주파수 할당 기법)

  • Kim, Jong Won;Kim, Sung Wook
    • KIPS Transactions on Computer and Communication Systems
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    • v.10 no.6
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    • pp.173-180
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    • 2021
  • Non Orthogonal Multiple Access (NOMA) is a technology to guarantee the explosively increased Quality of Service(QoS) of users in 5G networks. NOMA can remove the frequent orthogonality in Orthogonal Multiple Access (OMA) while allocating the power differentially to classify user signals. NOMA can guarantee higher communication speed than OMA. However, the NOMA has one disadvantage; it consumes a more energy power when the distance increases. To solve this problem, relay nodes are employed to implement the cooperative NOMA control idea. In a cooperative NOMA network, relay node participations for cooperative communications are essential. In this paper, a new bandwidth allocation scheme is proposed for cooperative NOMA platform. By employing the idea of Vickrey-Clarke-Groves (VCG) mechanism, the proposed scheme can effectively prevent selfishly actions of relay nodes in the cooperative NOMA network. Especially, base stations can pay incentives to relay nodes as much as the contributes of relay nodes. Therefore, the proposed scheme can control the selfish behavior of relay nodes to improve the overall system performance.

A Deep Learning Method for Cost-Effective Feed Weight Prediction of Automatic Feeder for Companion Animals (반려동물용 자동 사료급식기의 비용효율적 사료 중량 예측을 위한 딥러닝 방법)

  • Kim, Hoejung;Jeon, Yejin;Yi, Seunghyun;Kwon, Ohbyung
    • Journal of Intelligence and Information Systems
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    • v.28 no.2
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    • pp.263-278
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    • 2022
  • With the recent advent of IoT technology, automatic pet feeders are being distributed so that owners can feed their companion animals while they are out. However, due to behaviors of pets, the method of measuring weight, which is important in automatic feeding, can be easily damaged and broken when using the scale. The 3D camera method has disadvantages due to its cost, and the 2D camera method has relatively poor accuracy when compared to 3D camera method. Hence, the purpose of this study is to propose a deep learning approach that can accurately estimate weight while simply using a 2D camera. For this, various convolutional neural networks were used, and among them, the ResNet101-based model showed the best performance: an average absolute error of 3.06 grams and an average absolute ratio error of 3.40%, which could be used commercially in terms of technical and financial viability. The result of this study can be useful for the practitioners to predict the weight of a standardized object such as feed only through an easy 2D image.