• Journal of Korea Multimedia Society
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• v.16 no.8
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• pp.954-961
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• 2013

To enhance the efficiency of network, content-centric networking (CCN), one of future Internet architectures, allows network nodes to temporally cache transmitted contents and then to directly respond to request messages which are relevant to previously cached contents. Also, since CCN uses a hierarchical content-name, not a host identity like source/destination IP address, for request/response packet routing and CCN request message does not include requester's information for privacy protection, contents-providers/ network nodes can not identify practical requesters sending request messages. So to send back relevant contents, network nodes in CCN records both a request message and its incoming interfaces on Pending Interest Table (PIT). Then the devices refer PIT to return back a response message. If PIT is exhausted, the device can not normally handle request/response messages anymore. Hence, it is needed to detect/react attack to exhaust PIT. Hence, in this paper, we propose improved detection/reaction schemes against attacks to exhaust PIT. In practice, for fine-grained control, this proposal is applied to each incoming interface. Also, we propose the message framework to control attack traffic and evaluate the performance of our proposal.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.939-949
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• 2006

With the development of industry, product data management system is becoming more and more important. An expanded view of product definition function that include a bill of material and routing database, current and historical engineering data and specifications and engineering changes order history. PDM (Product Data Management) systems hold and manage such material as product specifications, plans, geometric models, CAD drawings and images. Furthermore, PDM enables companies producing complex products to spread product data in to the entire launch process. Especially, PDTnet XML Schema is an international standard for exchanging of PDM data. But PDTnet XML Schema differs from existing XML Schema in the way that its property of IDREF/IDREFS is irregular. Therefore it is important factor that. what do we use storage devices and storage techniques. We developed storage techniques and application supporting various query types and preserving PDTnet XML Schema using a relational database that guaranteeing the performance nowadays. In this paper, we will show that our storage techniques minimize repeated data and optimize query processing by using application comparison with storage techniques of existing XML Schema data.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1221-1234
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• 2010

MANET(Mobile Ad-hoc Network)s have been researched primary at routing protocols and at the guarantees of QoS(Quality of Service) for mobile environments. Otherwise the Ubiquitous Sensor Networks (USNs) have some limitations in power energies and in processing of sensing data, as well as their network topologies are frequently changed by fading off and node failures. Thus we should redesign network protocols with concerning to energy efficiency for the USNs above all. In this paper, we focus on the protocol interface for managing for USNs based on the surveys. And then we figure the topology of USNs out and design the network protocol interface to make power saved, with data gathering and processing more efficient using our designed packet structures.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1077-1088
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• 2013

As broadcasting is the process that a node sends a packet to all nodes in the network. it is basic process used for discovering of a routes to a node and disseminating of control information message in Mobile Ad hoc NETwork (MANET). In this paper, we propose dynamically adjusted probabilistic mechanism based on distance ratio and node density for broadcasting in MANETs. The distance ratio can be calculated as the ratio of the radio strength length to the distance from sender of a node, and node density can be get from 1-hop nodes of neighbours. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio and node density of itself. Rebroadcast probability will be set as low value to a node which is located in nearby area of sender and has high 1-hop node density, So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• Journal of Korea Multimedia Society
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• v.9 no.2
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• pp.244-254
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• 2006

This paper presents an efficient hybrid technique to compact the trie indexing the huge forward table small enough to be stored into cache for speeding up IP lookup. It combines two techniques, an encoding scheme called bit-map and a controlled-prefix expanding scheme to replace slow memory search with few fast-memory accesses and computations. For compaction, the bit-map represents each index and child pointer with one bit respectively. For example, when one node denotes n bits, the bit-map gives a high compression rate by consumes $2^{n-1}$ bits for $2^n$ index and child link pointers branched out of the node. The controlled-prefix expanding scheme determines the number of address bits represented by all root node of each trie's level. At this time, controlled-prefix scheme use a dynamic programming technique to get a smallest trie memory size with given number of trie's level. This paper proposes standard that can choose suitable trie structure depending on memory size of system and the required IP lookup speed presenting optimal memory size and the lookup speed according to trie level number.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12C
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• pp.1123-1130
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• 2009

The advances in networking technology and importance of multimedia communication require real time transaction. In many applications, high reliable real-time communications are required more frequently. In this paper, we propose a reliable communication in cube-based multi -computer using the safety vector. Each node in a cube-based n dimensional multi-computer is associated with a safety vector of n bits, which is an approximated measure of the number and distribution of faults in the neighborhood. We propose an algorithm that can establish detour paths using the safety vector. The established detour paths are disjoint with the primary real-time channel. Therefore, our algorithm is more efficient than earlier proposed algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.820-824
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• 2004

Personal Robot System in developing, have a module architecture, each module are connected through heterogeneors network systems like Ethernet, WLAN (802.11), IEEE1394 (Firewire), Bluetooth, USB, CAN, or RS-232C. In developing personal robot system we think that the key of robot performance is interoperability among modules. Each network protocol are well connected in the view of network system for the interoperability. So we make a bridging architecture that can routing, converting, transporting data packets with matcing each network's properties. Furthermore we suggest a advanced design scheme for realtime / non-realtime and control signal (short, requiring hard-realtime) / multimedia data (large, requiring soft-realtime). By some application systems, we could test performance, interoperability and stability. In this paper, we show our design concept, middleware architecture, and some applications systems using this middleware.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.163-166
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• 2003

In recent years, there has been increased to access multimedia service through the Internet due to rise of the access speed. We suppose the co-existence of the various access networks in adjacent area in the future, such as wireless LAN, Bluetooth, and 3G Cellular So, the size of the cell will be smaller and the number of access point will be increased. In other words, the potable devices need the efficient mobility scheme due to move between cells frequently Currently, the several of the scheme, which is Cellular IP, HAWAII, Mobile IPv4 regional registration, and hierarchical Mobile IPv6, is suggested to support micro-mobility but Mobile IPv4 is standard scheme to support the mobility of the mobile node. MPLS, which forwards the packet through switching instead of routing using IP address, has begun to deploy in the internet backbone to increase the performance of mobility protocol. The integration of both MPLS and Mobile IP improves the scalability of the Mobile IP data forwarding process by leveraging on the features MPLS which are fast switching and high scalability. Moreover it abbreviates IP-in-IP tunneling between HA and FA. In this paper, we suggest efficient mobility scheme through integration of both MPLS and hierarchical Mobile IPv6.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.308-310
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• 2012

최근 무선 센서 네트워크 환경에서 대용량 멀티미디어 데이터에 대한 요구가 증가하면서 통신 대역폭 및 한정적인 에너지의 한계를 극복하기 위한 대안으로 데이터 분할 및 다중 경로 기법들이 제안되었다. 기존 기법들은 데이터 전송 시에 발생하는 부하의 분산을 통해 네트워크의 성능을 향상시킬 수 있다는 것을 증명하였지만, 데이터의 효율적인 분할과 악의적인 공격에 의한 보안성 문제에 대해서 고려하지 않았다. 이러한 문제점을 해결하기 위해 본 논문에서는 비트평면 분할 기반의 보안성 있는 비-중첩 다중경로 라우팅 기법을 제안한다. 제안하는 기법은 멀티미디어 데이터를 비트평면 단위로 분할하여 다중 경로로 전송함으로써 기존의 키 기반의 암호화 기법을 사용하지 않고도 전체 네트워크에 대한 보안성을 향상 시켰다. 또한 경로 상 노드들의 잔여 에너지를 고려하여 데이터 전송을 수행함으로써 전체 네트워크의 에너지 효율성을 향상시켰다. 성능평가 결과, 제안하는 기법은 기존 기법에 비해 노드의 생존율이 평균 50% 이상 향상되었고, 데이터가 노출되더라도 해당 패킷을 가지고 본래 이미지를 복구하는 것이 불가능하기 때문에 높은 보안성을 제공한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.199-201
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• 2012

무선 멀티미디어 센서 네트워크를 활용하기 위한 응용에서는 대용량 멀티미디어 데이터 저장 및 처리 기술, 데이터 전송 기술 등과 같은 다양한 기반 기술들이 요구된다. 특히, 응용을 실제 환경에 적용하기 위해서는 대용량 데이터에 대한 데이터 보안 기술은 필수적이다. 본 논문은 여러 해킹 기술 중 하나인 스니핑 공격으로부터 원천적인 방어를 위해, 데이터 전송 경로를 위험 요소로부터 물리적으로 회피시키기 위한 다중 경로 라우팅 기법을 제안한다. 제안하는 기법은 위험 요소의 감지 반경과 움직임을 토대로 위험 요소의 인근에 위치한 센서 노드에 준비태세 단계를 설정한다. 이를 기반으로 데이터의 우선 순위를 설정하여 데이터 라우팅 과정에서 준비태세 단계와 데이터의 우선 순위를 고려하여 우선순위에 맞는 안전한 경로를 통해 위험요소 우회 다중 경로 라우팅을 수행한다. 시뮬레이션을 통해 제안하는 기법의 구현 가능성을 제시하였으며, 준비태세를 기반으로 효과적인 위험요소 우회 다중 경로 라우팅을 보였다.