• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.159-167
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• 2023

Objective: • To detect black hole and warm hole attacks in wireless sensor networks. • To give a solution for energy depletion and security breach in wireless sensor networks. • To address the security problem using strategic decision support system. Methods: The proposed stackelberg game is used to make the spirited relations between multi leaders and multi followers. In this game, all cluster heads are acts as leaders, whereas agent nodes are acts as followers. The game is initially modeled as Quadratic Programming and also use backtracking search optimization algorithm for getting threshold value to determine the optimal strategies of both defender and attacker. Findings: To find optimal payoffs of multi leaders and multi followers are based on their utility functions. The attacks are easily detected based on some defined rules and optimum results of the game. Finally, the simulations are executed in matlab and the impacts of detection of black hole and warm hole attacks are also presented in this paper. Novelty: The novelty of this study is to considering the stackelberg game with backtracking search optimization algorithm (BSOA). BSOA is based on iterative process which tries to minimize the objective function. Thus we obtain the better optimization results than the earlier approaches.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.1033-1035
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• 2005

일반적으로 기존의 Ad-hoc 무선 네트워크 환경에서의 라우팅 정책은 가장 빠르게 데이터를 전송할 수 있는 경로를 찾는 것이 목적이었다. 그러나 한정된 전력을 가진 노드로 구성한 네트워크에서 각 노드의 잔여전력량을 무시하고 라우팅 경로를 설정하면 수명을 다한 특정 노드로 인해 네트워크의 성능이 저하되는 문제점이 발생한다. 따라서 본 논문에서는 각 노드의 생존시간을 최대한 보장할 수 있도록 라우팅 경로를 선택하여 네트워크의 성능 저하를 최소화하는 라우팅 정책을 제안한다. 이 정책은 기존의 테이블 기반 라우팅 정책에 두 가지 metric을 더하여 잔여 전력이 많은 노드를 포함하는 경로를 설정할 수 있게 해 준다.

• ETRI Journal
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• v.35 no.3
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• pp.550-553
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• 2013

Due to limited spectrum resources and differences in link loads, network congestion is one of the key issues in cognitive radio wireless mesh networks. In this letter, a congestion avoidance model with power control, channel allocation, and routing under the signal-to-interference-and-noise ratio is presented. As a contribution, a nested optimization scheme combined with a genetic algorithm and linear programming solver is proposed. Extensive simulation results are presented to demonstrate the effectiveness of our algorithm.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.257-260
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• 2004

This paper describes the software download framework for SDR(Software Defined Radio). SDR is expected to solve the compatibility problem among various mobile communication standards so that people can use the same device for different wireless network. We integrated the SDR software download process into Jini architecture, and modified Jini's several functions. We implemented this proposed framework on a Linux and windows operating systems with Java programming language. With Java platform, we can easily transfer this framework into hand-held devices.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.379-383
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• 2007

무선 센서 네트워크에서는 네트워크 부하를 줄이기 위해 다수의 소스 노드가 전송한 데이터를 중간 노드에서 병합하여 전송하는 라우팅 기법을 사용한다. 기존의 DD-G(Directed Diffusion-Greedy) 데이터 병합 라우팅 기법은 데이터 병합 노드의 에너지 효율을 고려하여 단일 경로를 구축함으로써 에너지 소모를 줄일 수 있었다. 하지만 싱크 노드에 근접할수록 에너지 소모가 집중되거나 통신 지연이 증가하는 문제점이 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 부하 분산을 고려하여 다중 데이터 병합 경로를 구축하는 새로운 데이터 병합 라우팅 기법을 제안한다. 이 기법은 싱크 노드 주변의 네트워크 부하집중을 분산시키고, 데이터 손실에 대한 재전송 비용을 감소시키기 위해 다중 경로를 이용한다.

• ETRI Journal
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• v.31 no.3
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• pp.333-335
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• 2009

To match the requirements of heterogeneous mobile devices, video objects may be transcoded, which requires considerable CPU resources. Alternatively, multiple versions of the same video may be stored on servers, but this requires a lot of disk space. We formulate the trade-off between the versions that are stored on disk and the need for transcoding. We propose an optimal solution to this formulation based on dynamic programming. Experiments show that our scheme allows up to 68% more clients to be admitted than conventional schemes when a reasonable amount of storage is available.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.442-450
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• 2006

Inter-operability between heterogeneous radio access technologies (RATs), in the sense of seamless vertical han-dover (VHO) support with common radio resource management (CRRM) functionalities, has recently attracted a significant research attention and has become a prominent issue in standardization fora. In this paper, we formulate the problem of load balancing between cooperative RAT's as a mathematical program and by trading off a pre-defined delay tolerance per request we propose a vertical handover batch processing (VHBP) scheme. To quantify the performance of the proposed VHBP scheme we compare it with a baseline processing scheme, where each VHO request is processed independently under a number of different network scenarios. Numerical investigations reveal significant net benefits of the proposed scheme compared with the baseline, both in terms of achieved load balancing levels but also with regard to the acceptance rate of the VHO requests.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.13-20
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• 2008

Sensor network consists of a large number of sensor node distributed in the environment being sensed and controlled. The resource-constrained sensor nodes tend to have various and heterogeneous architecture. Thus, it is important to make its software environment platform-independent and reprogrammable. In this paper, we present BeeVM, a Java operating system designed for sensor networks. BeeVM offers a platform-independent Java programming environment with its efficiently executable file format and a set of class APIs for basic operating functions, sensing and wireless networking. BeeVM's high-level native interface and layered network subsystem allow complex program for sensor network to be short and readable. Our platform has been ported on two currently popular hardware platforms and we show its effectiveness through the evaluation of a simple application.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.155-164
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• 2000

Recently Fiber-optic Micro-cellular Wireless Network is considered to solve frequent handoffs and local traffic unbalance in microcellular systems. In this system, central station which is connected to several microcells by optical fiber manages the channels. We propose an efficient sectorization algorithm which dynamically clusters the microcells to minimize the blocked and handoff calls and to balance the traffic loads in each cell. The problem is formulated as an integer linear programming. The objective is to minimize the blocked and handoff calls. To solve this real time sectorization problem the Tabu Search is considered. In the tabu search intensification by Swap and Delete-then-Add (DTA) moves is implemented by short-term memory embodied by two tabu lists. Diversification is considered to investigate proper microcells to change their sectors. Computational results show that the proposed algorithm is highly effective. The solution is almost near the optimal solution and the computation time of the search is considerably reduced compared to the optimal procedure.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.552-556
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• 2005

이동통신사의 다양한 플랫폼은 콘텐츠 개발회사의 다중개발에 의한 경제적 손실을 발생시키고 경쟁력약화로 이어져 다양한 콘텐츠 개발에 집중하지 못하고 있는 문제점을 안고 있다. 이를 해결하기 위한 방안으로 기존의 무선인터넷 플랫폼 환경을 WIPI(Wireless Internet Platform (or Interoperability) 라는 모바일 표준 플랫폼으로 표준화하게 되었다. WIPI 표준 플랫폼은 다운로드에 의한 DLL(Dynamic Linking Library)을 지원함에 따라 무선망을 통해 동적으로 API (Application Programming Interface)를 추가/갱신하는 기능을 제공한다. 본 논문에서는 메모리 사용을 최소화 및 최적화하여 성능을 개선한 콘텐츠 뷰어를 개발하고, 이를 통해 동적 API 추가 및 갱신 모듈을 구현함으로써 효율적인 WIPI 콘텐츠 제작 환경을 제공하고자 한다.