• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4725-4747
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• 2020

Software defined networking (SDN) is considered to be one of the most promising paradigms in the future. To solve the scalability and performance problem that a single and centralized controller suffers from, the distributed multi-controller architecture is adopted, thus forms multi-domain SDN. In a multi-domain SDN network, it is of great importance to ensure a reliable control plane. In this paper, we focus on the reliability problem of multi-domain SDN against controller failure from perspectives of backup controller deployment and controller replication. We firstly propose a placement algorithm for backup controllers, which considers both the reliability and the cost factors. Then a controller replication mechanism based on shared data storage is proposed to solve the inconsistency between the active and standby controllers. We also propose a shared data storage layout method that considers both reliability and performance. Besides, a fault recovery and repair process is designed based on the controller backup and shared data storage mechanism. Simulations show that our approach can recover and repair controller failure. Evaluation results also show that the proposed backup controller placement approach is more effective than other methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권6호
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• pp.1674-1688
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• 2023

The remarkable advancement of quantum steganography offers enhanced security for quantum communications. However, there is a significant concern regarding the potential misuse of this technology. Moreover, the current research on identifying malicious quantum steganography is insufficient. To address this gap in steganalysis research, this paper proposes a specialized quantum steganalysis algorithm. This algorithm utilizes quantum machine learning techniques to detect steganography in general quantum secure communication schemes that are based on pure states. The algorithm presented in this paper consists of two main steps: data preprocessing and automatic discrimination. The data preprocessing step involves extracting and amplifying abnormal signals, followed by the automatic detection of suspicious quantum carriers through training on steganographic and non-steganographic data. The numerical results demonstrate that a larger disparity between the probability distributions of steganographic and non-steganographic data leads to a higher steganographic detection indicator, making the presence of steganography easier to detect. By selecting an appropriate threshold value, the steganography detection rate can exceed 90%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권2호
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• pp.511-527
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• 2024

This paper proposes a block-based self-organizing time-division multiple access (BSO-TDMA) protocol for very high frequency (VHF) data exchange system (VDES) in shipborne ad-hoc networks (SANETs). The BSO-TDMA reduces the collisions caused by the simultaneous transmission of automatic identification system (AIS) messages by uniformly allocating channel resources using a block-wise frame. For this purpose, the BSO-TDMA includes two functional operations: (1) frame configuration and (2) slot allocation. The first operation consists of block division and block selection. A frame is divided into multiple blocks, each consisting of fixed-size subblocks, by using the reporting interval (RI) of the ship. Then, the ship selects one of the subblocks within a block by considering the number of occupied slots for each subblock. The second operation allocates the slots within the selected subblock for transmitting AIS messages. First, one of the unoccupied slots within the selected subblock is allocated for the periodic transmission of position reports. Next, to transmit various types of AIS messages, an unoccupied slot is randomly selected from candidate slots located around the previously allocated slot. Experimental simulations are conducted to evaluate the performance of BSO-TDMA. The results show that BSO-TDMA has better performance than that of the existing SOTDMA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권7호
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• pp.1795-1816
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• 2024

A Software-Defined Wireless Sensor Networks (SDWSNs) architecture is firstly proposed to address the issues of inflexible architecture strategies and low scalability of traditional WSNs in this article. The SDWSNs architecture involves the design of a software-defined sensor network model and a customized controller architecture, along with an analysis of the functionalities of each management module within the controller architecture. Secondly, to tackle limited energy problem of sensor nodes, a network coding opportunistic routing method (SDN-COR) is presented based on SDWSNs. This method incorporates considerations of coding opportunities, vertical distance, and remaining energy of nodes to design a metric for encoding opportunistic routing. By combining opportunistic forwarding mechanisms, candidate forwarding sets are selected and sorted based on priority to prioritize data transmission by higher-priority nodes. Simulation results indicate that, comparing with conventional methods, this approach achieves reduction in energy consumption by an average of 21.5%, improves network throughput by 24%, and extends network lifetime by 20%.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.163-167
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• 2002

Recently, owing to performance elevation of telecommunication technology, increase of wireless internet's subscriber and diffusion of wireless device, Interest about LBS (Location Based Service) which take advantage of user's location information and can receive information in concerning with user's location is increasing rapidly. So, MOMS (Moving Object Management System) that manage user's location information is required compulsorily to provide location base service. LBS of childhood such as service to find a friend need only current location, but to provide high-quality service in connection with Data Mining, CRM, We must be able to manage location information of past. In this paper, we design distributed manage system to insert and search Moving Object in a large amount. It has been consisted of CLIM (Current Location Information Manager), PLIM (Past-Location Information Manager) and BLIM (Distributed Location Information Manager). CLIM and PLIM prove performance of searching data by using spatiotemporal-index. DLIM distribute an enormous amount of location data to various database. Thus it keeps load-balance, regulates overload and manage a huge number of location information efficiently.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 춘계학술발표대회
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• pp.95-98
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• 2010

OpenFlow 는 인터넷 스위치(라우터 포함)를 부분적으로 개선하여 연구자가 기존 네트워크의 정상적인 서비스를 간섭하지 않으면서 새로운 네트워킹 기술을 테스트할 수 있는 미래인터넷 (Future Internet) 연구를 위한 프로토콜이다. 하지만 OpenFlow 기반 테스트베드의 상태 정보를 확인하고 발생한 플로우들을 제어할 수 있는 도구(tool)가 부족하여, 연구자가 실험의 다양성을 제공 받기 어렵다. ENVI(Extensible Network Visualization & Control Framework)는 OpenFlow 네트워크 가시화를 위한 프레임워크로, 사용자의 목적에 맞는 인터페이스를 만들도록 제공해 준다. 본 논문에서는 OpenFlow 기반 테스트베드의 토폴로지 정보 및 플로우 상태를 쉽게 확인하고, 플로우 경로를 제어하는 OpenFlow 제어기 응용의 개발과 ENVI 의 확장을 설계하고 이를 구현을 통해 검증한다.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1184-1192
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• 2008

가상공간 즉 웹상에서 가상 실험실을 개발하여 공학 실험교육을 수행하려는 시도가 많이 이루어지고 있다. 본 논문에서는 가상교육의 현실성 부족이라는 문제점의 해결책으로 실시간 원격실험실을 제안하고 구현하였다. 원격실험실은 실험실험 관련 회로 및 장비를 웹상에서 원격 제어하여 실험을 하며, 그 결과 데이터 및 영상 정보를 되돌려 받을 수 있도록 하는 기능을 제공하여 학습자로 하여금 시간과 장소에 구애 없이 현장감 있는 실험학습을 수행할 수 있도록 설계 구현되었다. 서버 클라이언트 환경에서 개방형 JAVA WEB START 기술, FTP 기술, TELNET 기술 등 인터넷 활용 기술을 기반으로 하는 본 논문의 원격 실험실 모듈은 저렴한 비용으로 구현할 수 있고, 실시간 하드웨어 제어와 관련된 다양한 분야의 공학실험교육에 효과적으로 적용할 수 있을 것이다.

• 한국실천공학교육학회논문지
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• 제4권1호
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• pp.65-71
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• 2012

이 연구에서는 LabVIEW와 NI ELVIS를 이용하여 컴퓨터 기반의 공학교육 사례 즉 다양한 컴퓨터 기반의 공학실습을 소개한다. 여러 유명대학이나 연구소, 회사 등에서 웹/인터넷 또는 네트웍으로 제어되는 원격 실험과 같은 형태의 원격 실습이 가능하다. 컴퓨터 및 그래피칼프로그래밍 기술의 공학실습교육 적용을 통하여 공학 실험실습의 흥미와 효과를 제고하였다.

• Journal of Communications and Networks
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• 제8권2호
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• pp.234-240
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• 2006

We study the dynamic burst assembly based on traffic prediction and offset and delay differentiation in optical burst switching network. To improve existing burst assembly mechanism and build an adaptive flexible optical burst switching network, an approach called quality of service (QoS) based adaptive dynamic assembly (QADA) is proposed in this paper. QADA method takes into account current arrival traffic in prediction time adequately and performs adaptive dynamic assembly in limited burst assembly time (BAT) range. By the simulation of burst length error, the QADA method is proved better than the existing method and can achieve the small enough predictive error for real scenarios. Then the different dynamic ranges of BAT for four traffic classes are introduced to make delay differentiation. According to the limitation of BAT range, the burst assembly is classified into one-dimension limit and two-dimension limit. We draw a comparison between one-dimension and two-dimension limit with different prediction time under QoS based offset time and find that the one-dimensional approach offers better network performance, while the two-dimensional approach provides strict inter-class differentiation. Furthermore, the final simulation results in our network condition show that QADA can execute adaptive flexible burst assembly with dynamic BAT and achieve a latency reduction, delay fairness, and offset time QoS guarantee for different traffic classes.

• 한국통신학회논문지
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• 제41권10호
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• pp.1301-1308
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• 2016

인터넷 속도의 증가와 다양한 응용의 개발로 인해 인터넷 사용자와 이들이 발생시키는 인터넷 트래픽의 양이 급격히 증가하고 있다. 트래픽 분석에 있어서 트래픽 응용 식별 방법은 페이로드 시그니쳐에 의존적이기 때문에 시그니쳐의 구성이나 개수에 따라 높은 부하와 처리 속도가 느린 단점을 갖는다. 따라서 본 논문에서는 응용 식별을 위한 페이로드 시그니쳐의 중요도를 평가하는 방법과 이를 바탕으로 높은 효율의 시그니쳐를 탐색하는 방법을 제안한다. 각 시그니쳐 별로 3가지 기준을 바탕으로 가중치를 계산하고 계산된 가중치와 시그니쳐 맵을 통해 고효율의 시그니쳐 세트를 탐색한다. 제안하는 방법을 실제 트래픽에 적용했을 때 기존 대비 약 4배의 응용 식별 능력을 가진 높은 효율의 시그니쳐들을 정의할 수 있었다.