• 한국멀티미디어학회논문지
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• 제15권10호
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• pp.1212-1220
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• 2012

In this paper, a collision-free resource reservation scheme for WUSB (Wireless Universal Serial Bus) networks with WiMedia D-MAC (Distributed Medium Access Control). Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WUSB with WiMedia D-MAC can be deteriorated. In addition, when we consider multi-hop environment, "mobile" hidden node problem due to mobility of WUSB devices can be happened, and it is a critical problem to mobile WUSB devices transceiving real-time QoS (Quality of Service) traffic. To tackle the problem, we propose a new DRP reservation mechanism to prevent DRP conflicts for multi-hop mobility support in WUSB networks with WiMedia D-MAC and show its improved performance via simulation results.

• 한국멀티미디어학회논문지
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• 제15권4호
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• pp.516-525
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• 2012

본 논문에서는 와이미디어(WiMedia) 통신네트워크용 분산협력적 매체접근제어 프로토콜(D-MAC)의 멀티미디어 서비스 QoS를 개선하기 기법을 제안하였다. D-MAC방식은 고속 WPAN시스템에 적용하기 위한 것으로 기존에 제안된 중앙집중적 방식인 IEEE 802.15.3 프로토콜과 달리 모든 디바이스 장치들이 자원을 분산적 예약이 가능하게 하는 방식이다. 본 논문에서는 기존의 WiMedia 프로토콜에서는 채널의 링크 상태 변화를 적절하게 대처하지 못하여 발생하는 멀티미디어 QoS 감소문제를 해결하는 분산협력방식 DMAC 프로토콜 기법을 제안하여 성능을 분석하였다.

• 정보처리학회논문지B
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• 제9B권1호
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• pp.47-56
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• 2002

분산 멀티미디어 문서 시스템은 네트워크로 연결된 여러 서버에 있는 미디어들은 검색하여 제시된 시간 관계에 따라 미디어들을 프리젠테이션한다. 효과적인 프리젠테이션을 위해서는 동기화가 지원되어야 하며, 특히, 분산 환경에서의 프리젠테이션은 네트워크 대역폭과 지연시간 등에 의해 영항을 받기 때문에, 그러한 요소들이 고려되어 동기화가 지원되어야 한다. 본 연구에서는 분산 환경에서 프리젠테이션을 효과적으로 수행할 수 있는 분산 멀티미디어 프리젠테이션 시스템을 제안하고, 프리젠테이션을 위해 미디어들이 각 서버로부터 전송될 때 네트워크의 상태와 자원을 검사하여 그에 따른 변화를 서버에 피드백시켜, 서버로부터 전송되는 데이터의 양을 조절함으로서 동기화를 지원하기 위한 기법을 제안한다. 네트워크의 상태 변화를 효과적으로 파악하여 서버로 피드백하기 위해, 버퍼에 경계점을 설정하여 버퍼를 관리하는 기법과 서버로부터 패킷이 전송되는 시간과 클라이언트에 도착하는 시간의 차이를 체크하는 기법을 함께 사용하고 있다.

• 한국멀티미디어학회논문지
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• 제2권2호
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• pp.200-216
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• 1999

본 연구에는 멀티미디어 타이틀의 저작과 동기화 문제를 효과적으로 명세하고 분석할 수 있으며, 타이틀의 재생을 직접 제어할 수 있는 통합모형인 BTPN모형과 패러다임들을 제시한다 타이틀내의 객체들간의 모든 관계들을 BTPN구조와 BTPN언어로 명세하는 방법과 잔여시간형 도달성그래프, 타이밍다이어그램 둥을 이용하여 BTPN을 분석하는 방법을 제시하였다. 특히, PERT/CPM방법으로부터 도입한 임계객체경로나 최 장경로 개념은 타이틀 저작 및 재생시의 불확실성을 모형화하며 재생시간의 조정도 가능하게 하고 있다.

• Journal of Information Processing Systems
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• 제2권2호
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• pp.82-87
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• 2006

In spite of the rapid development of the public network, the variety of network-based developments currently raises numerous risks factors regarding copyright violation, the prohibition and distribution of digital media utilization, safe communication, and network security. Among these problems, multimedia data tend to increase in the distributed network environment. Hence, most image information has been transmitted in the form of digitalization. Therefore, the need for multimedia contents protection must be addressed. This paper is focused on possible solutions for multimedia contents security in the public network in order to prevent data modification by non-owners and to ensure safe communication in the distributed network environment. Accordingly, the Orthogonal Forward Wavelet Transform-based Scalable Digital Watermarking technique is proposed in this paper.

• 한국멀티미디어학회지
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• 제4권4호
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• pp.16-30
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• 2000

• 한국정보처리학회논문지
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• 제6권11호
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• pp.3034-3045
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• 1999

For efficiently providing multimedia services, distributed computing environments are specified the requirements of various services and distributed object platforms applied an object-oriented technology by TINA Consortium and OMG CORBA. Because multimedia service applications are becoming large and distributing, their servicing managing interfaces among objects are being complicated. In order to solve these defects, it is necessary to suggest a new object grouping model and specify object service/management requirements can be introduced under the object groups. We have been developed the distributed object group platform that can group all individual objects by the relating services and can supply trading functions for interconnecting between distributed objects or object groups. In this paper, we designed and implemented the Virtual Drawing Board for remote equational services on the distributed object group platform we mentioned above. As results, we designed a basic structure and service interfaces, and showed execution procedures of VDB system consisted of distributed objects and objects groups for educational services. For supporting distributed services of VDB system, we used three kinds of tools as follows; IONA orbix 2.2 of CORBA compliance as an object middleware, OrbixTrader 1.0 for interconnection of distributed objects, and the OGTG we developed for interconnection of distributed object groups and checking access rights of objects included in an arbitrary object group.

• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.33-41
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• 2020

Nowadays, distributed mobility management (DMM) approaches have been widely adopted to address the limitations of centralized architectural methods to support seamless data transmission schemes in wireless sensor networks. This paper deals with the end-to-end (E2E) integration of Network Mobility (NEMO) basic support protocol in distributed wireless sensor network systems in structural health and environmental monitoring of social overhead capital (SOC) public infrastructures such as bridges, national highways, tunnels, and railroads. The proposed scheme takes advantage of the features of both the NEMO basic support protocol and partially distributed network-based DMM framework in providing seamless data transmission and robust mobility support. The E2E seamless data transmission scheme allows mobile users to roam from fixed-point network access locations and mobile platforms (i.e., vehicles such as cars, buses, and trains) without disconnecting its current sessions (i.e., seamless handover).

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.64-68
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• 2016

These fields are integrated to visualize and finalize the proposed development, in simulation environment. SCADA (supervisory control and data acquisition) systems and distributed control systems (DCSs) are widely deployed in all over the world, which are designed to control the industrial infrastructures, in real ways. To supervise and control the various parts of designed systems; trends to require a deep knowledge to understand the overall functional needs of industries, which could be a big challenge. Industrial field devices (or network sensors) are usually distributed in many locations and are controlled from centralized site (or main control center); the communication provides various signs of security issues. To handle these issues, the research contribution will twofold: a method using cryptography is deployed in critical systems for security purposes and overall transmission is controlled from main controller site. At controller site, multimedia components are employed to control the overall transmission graphically, such as system communication, bytes flows, security embedded parameters and others, by the means of multimedia technology.

• 한국멀티미디어학회논문지
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• 제1권1호
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• pp.18-25
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• 1998

The basic requirements of distributed multimedia systems are intramedia synchronization which asks the strict delay and jitter for the check period of media buffer and the scaling duration with periodic continuous media such as audio and video media, and intermedia synchronization that needs the constraint for relative time relations among them when several media are presented in parallel. In this paper, a distributed intermedia synchronization algorithm that solves the intermedia synchronization problem by using variable service rates based on the fuzzy logic is designed and then the performance is evaluated through simulation.