• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.123-126
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• 2016

무선 센서 네트워크 하에서 불균일 네트워크의 에너지 효율은 주요 이슈 중의 하나로 고려된다. 불균일 네트워크에서, 개별 노드 초기 에너지의 무작위 분포는 네트워크 불안정을 초래할 수 있다. 따라서 네트워크 상 각 노드의 동작 시간 증가와 에너지 소비의 공평성 유지를 위해서는 적합한 방법이 마련되어야 한다. 본 논문에서는 서로 다른 시나리오의 불균일 네트워크 하의 분산 클러스터링 프로토콜(DCP)의 성능 평가를 보여준다. 본 시뮬레이션 결과는 불균일 네트워크에서의 LEACH 프로토콜 결과와 비교하였다. 추가적으로 불균일 네트워크에서의 시스템 성능을 균일 네트워크와 비교함으로써, 불균형 초기 에너지가 시스템의 개별 노드의 수명에 미치는 영향을 설명한다. 시뮬레이션 수행 결과 균일 및 불균일 네트워크에서 LEACH 프로토콜과의 성능 비교 결과는 DCP의 성능이 모든 경우에 성능 우위에 있음을 나타내었다.

• 한국멀티미디어학회논문지
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• 제11권4호
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• pp.504-515
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• 2008

유선 네트워크의 빠른 전송속도 및 다양한 서비스와 무선의 편리성 및 이동성이 결합되어 새로운 서비스 영역을 창출하고 사용자와 서비스 제공자 모두에게 새로운 변화를 가져올 신기술로 유/무선 통합 시대가 전개되고 있다. 유/무선 통합 서비스 중에서 네트워크의 통합은 이기종 네트워크간 연동에 의한 네트워크 융합과 네트워크상에서 전송기술간 융합으로써 매주 중요한 부분을 차지하고 있다. 이러한 상황 속에서 이기종 네트워크의 융합은 서로 다른 네트워크의 융합으로 인해 기존의 보안 기술 및 통신 기술을 그대로 적용하기가 매우 어려우며, 보안 측면에서도 많은 취약점을 내포하고 있다. 기존의 동종 네트워크에서 사용자의 인증 및 키 관리와는 다르게 이기종 네트워크간의 사용자 인증 및 키 관리는 새로운 기술이 필요한 실정이며 또한 동종 네트워크에서 이기종 디바이스간의 보안 기술 확립은 매우 중요한 사항이라 할 수 있다. 본 논문에서는 이기종 네트워크 환경에서의 안전하고 효율적인 키 관리를 제안하여, 이기종 네트워크 디바이스간의 안전한 통신을 제공 할 수 있다.

• 한국통신학회논문지
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• 제35권7B호
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• pp.1009-1017
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• 2010

Offering of different attractive opportunities by different wireless technologies trends the convergence of heterogeneous networks for the future wireless communication system. To make a seamless handover among the heterogeneous networks, the optimization of the power consumption, and optimal selection of interface are the challenging issues. The access of multi interfaces simultaneously reduces the handover latency and data loss in heterogeneous handover. The mobile node (MN) maintains one interface connection while other interface is used for handover process. However, it causes much battery power consumption. In this paper we propose an efficient interface selection scheme including interface selection algorithms, interface selection procedures considering battery power consumption and user mobility with other existing parameters for overlaying networks. We also propose a priority based network selection scheme according to the service types. MN‘s battery power level, provision of QoS/QoE and our proposed priority parameters are considered as more important parameters for our interface selection algorithm. The performances of the proposed scheme are verified using numerical analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4948-4967
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• 2017

On mobile devices, image sequences are widely used for multimedia applications such as computer vision, video enhancement, and augmented reality. However, the real-time processing of mobile devices is still a challenge because of constraints and demands for higher resolution images. Recently, heterogeneous computing methods that utilize both a central processing unit (CPU) and a graphics processing unit (GPU) have been researched to accelerate the image sequence processing. This paper deals with various optimizing techniques such as parallel processing by the CPU and GPU, distributed processing on the CPU, frame buffer object, and double buffering for parallel and/or distributed tasks. Using the optimizing techniques both individually and combined, several heterogeneous computing structures were implemented and their effectiveness were analyzed. The experimental results show that the heterogeneous computing facilitates executions up to 3.5 times faster than CPU-only processing.

• 환경위생공학
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• 제16권2호
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• pp.38-46
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• 2001

In this work, the heterogeneous ion exchange membrane was used in a electrodialysis apparatus to treat a Ni planting rinse water because the heterogeneous ion exchange membrane was excellent efficiency as compared with low manufacturing cost, was easy to make, and had a good mechanical properties. For a regeneration of membrane and to obtain the optimal condition for a scale-up of apparatus after treating Ni plating rinse water, we would find about the limiting current density and the concentration polarization. When the Ni plating rinse water 150mg/L was treated with the electrodialysis apparatus using the heterogeneous ion exchange membrane, the limiting current density was about $1.49{\;}mA/\textrm{cm}^2$. And the limiting current density increased with the flow rate and concentration of Ni plating rinse water. We recognized that the used membrane could be reused by periodic backwashing because efficiency was constant when the membrane was backwashed after treating wastewater.

• ETRI Journal
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• 제38권3호
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• pp.529-539
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• 2016

Recently, a product-matrix (PM) framework was proposed to construct optimal regenerating codes for homogeneous distributed storage systems (DSSs). In this paper, we propose an extended PM (EPM) framework for coding of heterogeneous DSSs having different repair bandwidths but identical storage capacities. Based on the EPM framework, an explicit construction of minimum remote-repair bandwidth regenerating (MRBR) codes is presented for a specific heterogeneous DSS, where two geographically different datacenters with associated storage nodes are deployed. The data reconstruction and regeneration properties of the MRBR code are proved strictly. For the purpose of demonstration, an example implementation of MRBR code is provided. The presented MRBR code is the first optimal strict-regenerating code for heterogeneous DSSs. In addition, our proposed EPM framework can be applied to homogeneous systems also.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.68-86
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• 2015

Future wireless network aims to integrate different radio access networks (RANs) to provide a seamless access and service continuity. In this paper, a new resource denotation method is proposed in the WLAN and LTE heterogeneous networks based on a concept of spectral bandwidth mapping. This method simplifies the denotation of system resources and makes it possible to calculate system residual capacity, upon which an economic model-based network selection algorithm is designed in both under-loaded and over-loaded scenarios in the heterogeneous networks. The simulation results show that this algorithm achieves better performance than the utility function-based access selection (UFAS) method proposed in [12] in increasing system capacity and system revenue, achieving load balancing and reducing the new call blocking probability in the heterogeneous networks.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.544-547
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• 2013

차세대 네트워크 환경은 유선과 무선, 방송과 통신, 음성과 데이터의 융합을 고려한 통합망 형태로 진화하고 있다. 특히, 인터넷 프로토콜(IP) 기반의 코어 네트워크(Core network)를 중심으로 다양한 접속기술을 갖는 서로 다른 이기종(Heterogeneous) 접속망이 존재하는 환경에서 대용량의 멀티미디어 서비스들을 언제, 어디서나, 이동 중에도 끊김 없이 제공받고자 하는 사용자의 요구 또한 증가하고 있는 상황이다. 본 논문에서는 이러한 융합 서비스 관리자로서 유비쿼터스 식별자(UID)를 사용하여 통합된 식별체계와 인증 및 과금을 지원하고 통합 프로파일 관리를 통하여 사용자 정보를 서비스 제공자에게 제공하는 알고리즘을 구현 단말이 이동되는 경우에도 융합 서비스를 제공할 수 있도록 제시한다.

• 경영과학
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• 제26권1호
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• pp.113-126
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• 2009

By the newly emerging network access technology, we face the new heterogeneous network environment. Focusing on the co-existence of multiple access network technology and the complex service needs of users, the wireless service operators should present the stable service quality for every user. For this, the service operators should build the new operation framework which combine the pre-established network and newly adopted one. Our problem is finding the optimal heterogeneous network operation framework. We suggest market-based marginal cost function for evaluating the relative value of resource of each network and develop the whole new heterogeneous network operation framework. To test the applicability of developed operation framework, we build large-scale JAVA simulator. By this development, we can easily test the new network environment in practical engineering field.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4405-4418
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• 2015

Different network provides different service. To maximize the profit, heterogeneous networks form a whole, which may either compete or cooperate with each other. In this paper, the healthcare monitor network architecture is introduced to build the competitive and cooperative mechanisms of heterogeneous networks which contain three networks, namely, cellular network, WLAN and WMAN. This paper considers the natural growth rate of the network with competitive and cooperative effects. Then, the stability of the proposed model and its equilibrium points are analyzed by the ordinary differential principle. Finally, simulation results show that the natural growth rate cannot increase the profit of the network, but effective cooperative among heterogeneous networks can increase the profit of each network, and competitive may decrease the profit of each network.