• 문화기술의 융합
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• 제6권4호
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• pp.203-208
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• 2020

미국과 중국의 무역전쟁이 수년 간 지속되고 있고, 미국의 중국통신기업에 대한 제재는 점점 강화되고 있다. 이런 재제에도 중국의 대표적 통신장비업체인 ZTE(중싱)은 글로벌 5세대 이동통신(5G) 시장에서 점유율을 오히려 확대하고 있다. 이러한 ZTE의 성장과 경쟁력은 ZTE의 독특한 기업문화에 기반하고 있다. ZTE는 연구개발을 중시하며, 적재적소에 인재배치 및 활용, 중국 전통문화에 기반하여 겸손과 절제, 중용의 '온정문화(溫情文化)'라는 기업문화를 가지고 있다. ZTE는 사람중심 경영을 구현하기 위해 노력하면서, 내부경쟁을 적절히 활용하고 있다. ZTE의 기업문화는 상호 존중, 충실함, 혁신, 우수한 서비스, 연구개발과 브랜드 중시, 직원배려와 과학적 관리의 결합 등으로 설명된다. ZTE의 세계적 시장점유율과 기업경쟁력에도 불구하고, 한국에서는 연구된 바가 사실상 전무하다. 본 연구결과를 통해, 중국의 ICT산업과 통신장비기업에 대한 이해의 폭을 넓히고자 한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 가을 학술발표논문집 Vol.27 No.2 (2)
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• pp.538-540
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• 2000

본 논문에서는 적응적인 웨이블릿 변환에 기초한 저속 비트율 비디오 코딩 방법의 새로운 알고리즘을 제안한다. 접근 방법은 양자화된 웨이블릿 계수들이 웨이블릿 서브밴드 구조내에서 중복성을 활용하는 메커니즘에 의해서 전처리 된다면 코딩 절차가 더욱 효과적으로 나타난다. 그러므로 본 논문에서는 코딩부분의 최적화 활동에 초점을 맞추어 완전한 중복 블록 움직임 보상된 에어프레임에서 일치를 확보하기 위해 이용하고, 향상된 코사인 윈도우를 적용하였다. 또한 웨이블릿 변환은 각 일치한 움직임 보상된 에러 프레임을 전체적인 에너지 컴팩션에 도달하도록 적용된다. 움직임 벡터의 수평적, 수직적 컴포넌트는 적응적 산술적 코딩을 사용하여 독립적으로 인코드되는 반면에 의미있는 웨이블릿 계수는 적응적 산술 코딩을 사용함에 의해서 비트-플레인 순서로 인코드된다. 제안된 부호기는 28Kbits에서 PSNR이 평균적으로 각각 대략 2.07과 1.38dB에 존재하는 H.263과 ZTE를 초과한다. 전체순서 코딩에 대하여도 3DWCVC 방법은 평균적으로 각각 0.35와 0.71dB을 나타내는 H.263과 ZTE보다 우수한 성능을 보인다.

• 한국정보처리학회논문지
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• 제7권2S호
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• pp.701-710
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• 2000

This paper presents a new method for an efficient coding of very low bit-rate color video based on adaptive wavelet transform. Our approach reveals that the coding process works more efficiently if the quantized wavelet coefficients are preprocessed by a mechanism exploiting the redundancies in the wavelet subband structure. Thus, we focuses optimized activity of coding part, and exhaustive overlapped block motion compensation is utilized to ensure coherency in motion compensated error frames, and raised cosine window is applied. The horizontal and vertical components of motion vectors are encoded separately using adaptive arithmetic coding while significant wavelet coefficients are encoded in bit-plane order using adaptive arithmetic coding. On average the proposed codec exceeds H.263 and ZTE in peak signal-to-noise ratio by as much as 2.07 and 1.38dB at 28 kbits, respectively. Fore entire sequence coding, 3DWCVC method is superior to H.263 and ZTE by 0.35 and 0.71dB on average, respectively.

• 한국융합학회논문지
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• 제8권8호
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• pp.1-8
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• 2017

최근 전 세계적으로 사물 인터넷 분야의 기술 개발이 매우 활발히 이루어지고 있으며, 선진국들은 물론 중국의 성장세가 매우 두드러진 실정이다. 따라서, 본 논문은 사물 인터넷 분야에서 중국의 특허출원 현황을 분석하는 것을 목적으로 하였으며, 분석 결과는 다음과 같다. 첫째, 사물인터넷 관련한 중국 특허는 2010년부터 급격히 증가하였으며, 2014년까지는 미국을 앞지르는 양적 증가 추세를 보였다. 둘째, 이러한 양적 증가를 견인하는 주체는 ZTE를 비롯한 기업들과 난징우전대학(Nanjing University of Posts and Telecommunications)과 같은 고등 교육 기관들로 나타났다. 마지막으로 주요 기술분야 및 기술분야간 융합 네트워크 분석을 실시하였다. 그 결과, H04L(Electronic Communication Technique: 전기 통신 기술) 기술분야의 특허가 가장 활발히 출원되었을 뿐 아니라, 다른 기술분야와의 융합을 주도하고 있음을 알 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.908-911
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• 2002

Over the past 30 years, many efficient 2D video coding techniques have been presented and developed from many research centers for commercialization. However, direct application of these monocular compression schemes is not optimal for stereo video coding. In this paper, we present a new technique for coding stereo video sequences based on Discrete Wavelet Transform (DWT). The proposed technique exploits Zerotree Entropy Coding (ZTE) that makes use of the wavelet block concept to achieve low bit rate stereo video coding. The one of two image streams, called main stream, is independently coded by modified MPEG-4 encoder and the other stream, called auxiliary stream, is coded by predicting from its corresponding image, its previous image or its follow image.

• 산경연구논집
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• 제6권1호
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• pp.27-35
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• 2015

Purpose - This research primarily assesses interactive quality in the service encounters of Ethiopian Telecom from the customer and contact personnel perspectives. Research design, data, and methodology - After reviewing the literature on service encounters and interactive quality, two separate questionnaires and structured personal interviews were conducted to collect the opinions of 400 customers and 100 employees of Ethiopian Telecom. The researchers used convenience sampling; the responses, measured on a five-point Likert-type scale, were analyzed through chi-square tests conducted on SPSS 17.0. Results - Regarding the outcome expected by customers, encounter effectiveness is very low. Regarding accessibility and materiality, the corporation's personnel are freely accessible, relatively well-dressed, and have access to sophisticated office equipment and physical facilities. Finally, with regard to agent satisfaction, the telecom's contact employees are shown to gain little professional satisfaction from service encounters. Conclusion - The study clearly presents the areas in which interactive quality strongly affects both telecom customers and employees; this will help the corporation take corrective action. This is of utmost contemporary importance for both practitioners and researchers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.2797-2820
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• 2015

In order to accommodate huge number of antennas in a limited antenna size, a large scale antenna array is expected to have a three dimensional (3D) array structure. By using the Active Antenna Systems (AAS), the weights of the antenna elements arranged vertically could be configured adaptively. Then, a degree of freedom (DOF) in the vertical plane is provided for system design. So the three-dimension MIMO (3D MIMO) could be realized to solve the actual implementation problem of the massive MIMO. However, in 3D massive MIMO systems, the pilot contamination problem studied in 2D massive MIMO systems and the inter-cell interference as well as inter-vertical sector interference in 3D MIMO systems with vertical sectorization exist simultaneously, when the number of antenna is not large enough. This paper investigates the interference management towards the above challenges in 3D massive MIMO systems. Here, vertical sectorization based on vertical beamforming is included in the concerned systems. Firstly, a cooperative joint vertical beams adjustment and pilot assignment scheme is developed to improve the channel estimation precision of the uplink with pilots being reused across the vertical sectors. Secondly, a downlink interference coordination scheme by jointly controlling weight vectors and power of vertical beams is proposed, where the estimated channel state information is used in the optimization modelling, and the performance loss induced by pilot contamination could be compensated in some degree. Simulation results show that the proposed joint optimization algorithm with controllable vertical beams' weight vectors outperforms the method combining downtilts adjustment and power allocation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권3호
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• pp.916-937
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• 2023

Most of the existing Distributed Denial-of-Service mitigation schemes in Software-Defined Networking are only implemented in the network domain managed by a single controller. In fact, the zombies for attackers to launch large-scale DDoS attacks are actually not in the same network domain. Therefore, abnormal traffic of DDoS attack will affect multiple paths and network domains. A single defense method is difficult to deal with large-scale DDoS attacks. The cooperative defense of multiple domains becomes an important means to effectively solve cross-domain DDoS attacks. We propose an efficient multi-domain DDoS cooperative defense mechanism by integrating blockchain and SDN architecture. It includes attack traceability, inter-domain information sharing and attack mitigation. In order to reduce the length of the marking path and shorten the traceability time, we propose an AS-level packet traceability method called ASPM. We propose an information sharing method across multiple domains based on blockchain and smart contract. It effectively solves the impact of DDoS illegal traffic on multiple domains. According to the traceability results, we designed a DDoS attack mitigation method by replacing the ACL list with the IP address black/gray list. The experimental results show that our ASPM traceability method requires less data packets, high traceability precision and low overhead. And blockchain-based inter-domain sharing scheme has low cost, high scalability and high security. Attack mitigation measures can prevent illegal data flow in a timely and efficient manner.