• 한국멀티미디어학회논문지
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• 제10권3호
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• pp.373-380
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• 2007

본 논문에서는 Personal Area Network (PAN)을 구성하는 모바일 디바이스에서의 전자서명 생성 및 검증을 위한 계산상 오버헤드를 감소시키는 효율적인 인증 프로토콜을 제안한다. 특히, 제안 프로토콜은 일회용 전자서명 기법을 사용함으로써 전통적인 공개키 전자서명 연산을 제거하였으며, 제한된 컴퓨팅 능력을 가진 모바일 디바이스를 위해 기 제안된 인증 프로토콜과 달리 서명 서버의 지원없이 전자서명 생성 및 검증을 수행할 수 있다. 또한, 제안 프로토콜은 PAN에서 모바일 디바이스들의 인증서 상태 관리를 위한 통신 및 계산상 오버헤드를 경감시키기 위해 해쉬체인에 기반한 간략화된 인증서 상태 검증 절차를 제공한다.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.405-412
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• 2014

Due to the popularity of mobile phones, Peer-to-Peer (P2P) content sharing in mobile phones is highly desirable, especially in a mobile data connection. In addition, there has been an increasing demand for content sharing applications for P2P communication in Android-based smartphones as ubiquitous mobile devices. However, due to wireless network limits, unstable characteristic and restricted storage space, mobile users confront challenges in establishing connections and sharing video frames with other users. To solve this issue, we propose an architectural design and implementation of key frame sharing application that uses Chord, a distributed lookup protocol to establish a content sharing platform for mobile devices, combined with the Chord SDK based on Android. Our proposed system enables users easily to share key information on video data in real-time over a wireless network without manual processing of devices which join or leave the group and cost associated with the 3G/4G network.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.441-457
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• 2014

Observed from the recent performance evaluation of clustering schemes in wireless sensor networks, we found that most of them did not consider various sensor characteristics and its application environment. Without considering these, the performance evaluation results are difficult to be trusted because these networks are application-specific. In this paper, for the fair evaluation, we measured several clustering scheme's performance variations in accordance with sensor data pattern, number of sensors per node, density of points of interest (data density) and sensor coverage. According to the experiment result, we can conclude that clustering methods are easily influenced by POI variation. Network lifetime and data accuracy are also slightly influenced by sensor coverage and number of sensors. Therefore, in the case of the clustering scheme that did not consider various conditions, fair evaluation cannot be expected.

• 한국멀티미디어학회논문지
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• 제20권2호
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• pp.216-224
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• 2017

Abnormal situation caused by aggressive behavior of pigs adversely affects the growth of pigs, and comes with an economic loss in intensive pigsties. Therefore, IT-based video surveillance system is needed to monitor the abnormal situations in pigsty continuously in order to minimize the economic demage. Recently, some advances have been made in pig monitoring; however, detecting each pig is still challenging problem. In this paper, we propose a new color image-based monitoring system for the detection of the individual pig using a fast region-based convolution neural network with consideration of detecting touching pigs in a crowed pigsty. The experimental results with the color images obtained from a pig farm located in Sejong city illustrate the efficiency of the proposed method.

• 한국멀티미디어학회논문지
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• 제7권1호
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• pp.113-125
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• 2004

능동 네트워크는 능동 네트워크 애플리케이션의 통신 중 요구사항의 처리를 할 수 있게 하는 소프트웨어 프레임 워크를 제공한다. 능동보안을 위한 컴포넌트 아키텍쳐는 관련 컴포넌트들의 조합으로 재사용 시스템을 쉽게 구축할 수 있다. 이 아키텍쳐는 컴포넌트를 획득하고, 이해하며 조립하기 위한 표준 계층으로서 컴포넌트 식별, 탐색과 조정을 위한 지침을 제공해야 한다. 본 논문에서는 최근 연구되어지고 있는 능동네트워크의 보안에 대한 부분을 관리하기 위한 능동보안 컴포넌트 개발을 위한 아키텍쳐 설계 및 도메인 분석을 하였으며, 능동보안 도메인 아키텍쳐를 이용한 컴포넌트 개발을 위한 설계명세에 대하여 연구하였다.

• Journal of Multimedia Information System
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• 제3권2호
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• pp.21-26
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• 2016

Our networked world has been growing exponentially fast. The explosion in volume of machine-to-machine (M2M) transactions threatens to exceed the transport capacity of the networks that link them. Therefore, it is quite essential to reconsider the tradeoff between using many data sets versus using good data sets. We focus on this tradeoff in the context of the quality of information aggregated from many sensors in a noisy environment. We start with a basic theoretical model considered in the famous "CEO problem'' in the field of information theory. From a point of view of large deviations, we successfully find a simple statement for the optimal strategies under the limited network capacity condition. Moreover, we propose an open problem for a sensor network scenario and report a numerical result.

• 한국통신학회논문지
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• 제34권11B호
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• pp.1191-1199
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• 2009

As the Internet service evolves from the best effort data service to a multimedia service such as a mix of voice, data and video, a need for the guarantee of the quality of service to network services became one of the hot issues for the network operators. On the other hand, the introduction of the multimedia services over the IP network requires a managed differentiated service that adopts a prioritized treatment of packets. This incurs a need for a differentiated pricing scheme for the packets that receive different level of quality of service. This work proposes an analytic framework about packet pricing scheme for these services, and investigate the effect of service differentiation to the packet price for each class. Via numerical experiment, we validate our argument and illustrate the implication of the work.

• 전자공학회논문지A
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• 제33A권4호
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• pp.57-67
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• 1996

This paper aims to support delay-sensitive multimedia applications by suggesting a mechanism in which maintains almost constant end-to-end delay thus providing the optimum playout synchronization. For this task the sum of network delay and buffering delay is entiredly managed and to eliminate little delay fluctuations and instantaneous delays at a buffer and a network, a low pass filter is used. Furthermore the correction function, which is used for maintaining the buffering level ot a reference value, is a non-linear step function, unlike the existing linear and continuous function. it has a different step sizes adapting to a traffic characteristics of a network congestion. the proposed mechanism has been confirmed of it sefficiency through SLAM-II netowrk.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.105-108
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• 2003

In the next generation backbone networks based on dense-wavelength division multiplexing (DWDM), the routing and wavelength assignment with quality-of-service (QoS) recovery is essentially needed to support a wide range of communication-intensive and real-time multimedia services. This paper proposes a new dpmic routing method called as MW-MIPR (MultiWavelength-Minimum Interference Path Routing), which chooses a route that does not interfere too much with many potential future connection requests. This paper also proposes a differentiated RWA mechanisms combined with MW-MIPR algorithm to provide QoS recovery for various multimedia applications in the next generation backbone networks based on DWDM.

• 한국통신학회논문지
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• 제37권7B호
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• pp.550-564
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• 2012

In this work we propose a new pricing scheme for the wireless Internet services over WiMAX system. First, let us review the characteristics of wireless network which is based on multi-hop relay WiMAX system. Next, we show why usage-based and QoS-aware pricing scheme is needed in the wireless Internet. After that, we propose a theoretical model for the price of multimedia services called a DAP (DiffServ-aware pricing) scheme for the WiMAX multimedia network which takes into account the consumed radio resource of WiMAX system as well as the supported QoS in the IP backbone network. Finally, we present explicit formulae for the packet price, price of consumed radio resource, and price of consumed bytes.