• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1216-1224
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• 2009

This paper presents cross-layer based packet scheduling and routing algorithm to effectively transmit delay-sensitive multimedia data over mobile ad hoc network. At first, packet urgency, node urgency, and route urgency are defined based on the end-to-end delay requirement of each packet and the number of hops over a route. Based on the urgency metric, the proposed transmission scheme is that packet scheduling algorithm at the MAC layer and routing algorithm at the network layer are tightly-coupled to improve the transmission performance for delay-sensitive multimedia. Finally, simulation results are provided to show the performance of proposed transmission scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1173-1178
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• 2007

Ubiquitous sensor network (USN) is composed of many sensor nodes which are one of the simplest form of embedded system. In developing the sensor network system, a debugging tool is necessary to test and verify the system. Recently, a so-called packet analyzer has been developed for this purpose, and it supports IEEE 802.15.4 which is considered as the standard for the sensor network protocols. The major function of the packet analyzer is to take RF packets from sensor nodes and show the structure and the data of the packets graphically to the user. However, the conventional packet analyzers do not support remote control because they require a USB interface along with a personal computer. To make it available for remote control, we propose a new packet analyzer based on a server-client scheme in which a server program is implemented on embedded Linux and a client program is implemented on Windows for convenient use.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3150-3171
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• 2018

In this paper, a heuristic method that leverages packet traces captured at the entire boarder of an ISP to distinguish and estimate the overall packet loss within an ISP's management domain (Intra_Path_Loss) and that in the outside Internet (Inter_Path_Loss) is proposed. Our method is inspired by that packet losses happened at different locations will cause different TCP sequence number patterns at the border of an ISP. Thereby, we leverage these TCP sequence number patterns to build a series of heuristic rules to estimate Intra_Path_Loss and Inter_Path_Loss, respectively. We do this work with an eye towards showing that the overall packet losses defined and estimated in this paper can provide the operators with some valuable information to help them precisely grasp the overall performance of network paths and narrow down the range of network anomalies. The proposed method is rigorously validated with simulations, and finally the results from a regional academic network JSERNET verify its effectiveness and practicability.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.279-289
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• 2009

As the TCP is the protocol designed for the wired network that packet loss probability is very low, because TCP transmitter takes it for granted that the packet loss by the wireless network characteristics is occurred by the network congestion and lowers the transmitter's transmission rate, the performance is degraded. In this article, we suggest the newly improved algorithm using two parameters, the local retransmission time value and the local retransmission critical value to the BS based on the Snoop. This technique adjusts the base stations local retransmission timer effectively according to the wireless link status to recover the wireless packet loss rapidly. We checked that as a result of the suggested algorithm through various simulations, A-Snoop protocol improve more the wireless TCP transmission rate by recovering the packet loss effectively in the wireless link that the continuous packet loss occur than the Snoop protocol.

• Information and Communications Magazine
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• v.24 no.11
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• pp.25-36
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• 2007

Deep packet inspection is widely recognized as a powerful way which is used for intrusion detection systems for inspecting, deterring and deflecting malicious attacks over the network. Fundamentally, almost intrusion detection systems have the ability to search through packets and identify contents that match with known attach. In this paper we survey the deep packet inspection implementations techniques, research challenges and algorithm. Finally, we provide a comparison between the different applied system.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.328-333
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• 2004

SK Telecom은 2000년 10월 세계 최초로 기존 IS-95A/B망에서 지원하였던 속도인 14.4Kbps나 56Kbps 보다 훨씬 빠른 최고 144Kbps로 무선인터넷이 가능한 CDMA2000 IX를 상용화 하였다. 또한, 2002년 1월에는 CDMA2000 IX보다 15배 이상 빠른 최대 2.4Mbps가 가능한 동기식 3세대 망인 CDMA2000 IxEV-DO를 세계 최초로 상용화 하였다. 이러한 초고속 무선 인터넷 서비스를 위해서 패킷 데이터 처리에 필수적인 PDSN(Packet Data Serving Node), HA(Home Agent), AAA(Authentication, Authorization and Accounting) 등의 노드들로 구성된 Packet Core Network(이하 PCN)이 도입되었으며, 이에 대한 운용 및 관리 방안이 중요한 issue로 등장하였다. 본 논문에서는 기존의 음성 서비스 관리를 위한 망관리 시스템(Network Management System)과는 다른 개념으로 관리되어야 할 패킷 서비스를 위한 NMS 구축 방안을 제시하고, 필수적인 관리 정보 및 서비스 관리를 위한 방향을 제시한다.

• ETRI Journal
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• v.39 no.2
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• pp.275-283
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• 2017

A green technology for reducing energy consumption has become a critical factor in ICT industries. However, for the telecommunications sector in particular, most network elements are not usually optimized for power efficiency. Here, we propose a novel energy-efficient packet switching method for use in an IP network for reducing unnecessary energy consumption. As a green networking approach, we first classify the network nodes into either header or member nodes. The member nodes then put the routing-related module at layer 3 to sleep under the assumption that the layer in the OSI model can operate independently. The entire set of network nodes is then partitioned into clusters consisting of one header node and multiple member nodes. Then, only the header node in a cluster conducts IP routing and its member nodes conduct packet switching using a specially designed identifier, a tag. To investigate the impact of the proposed scheme, we conducted a number of simulations using well-known real network topologies and achieved a more energy- efficient performance than that achieved in previous studies.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.659-665
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• 2015

Recent studies on network coding scheme for increasing transmission efficiency of the network has been actively conducted. In this paper, we apply RLNC in sub-packet unit and propose a joint scheme of sub-packet level network coding and LDPC code. The proposed method can have similar ability of network coding and obtain further error correction capability. The simulation results show that the proposed one enhances error correction capability compared to the case using only LDPC when extra packets are received.

• Proceedings of the IEEK Conference
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• summer
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• pp.39-41
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• 2004

In this paper, I propose a thread scheduling policy for faster packet processing on the network processors with multithreaded multiprocessor architecture. To implement the proposed policy, I derived several basic parameters related to the thread scheduling and included a new parameter representing the packet contents and the features of the multithreaded architecture. Through the empirical study using a network processor, I proved the proposed scheduling ploicy provides better throughput and load balancing compared to the generally used thread scheduling policy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.805-814
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• 1994

In this paper, we introduce a new method which is available for analyzing the throughput of the packet radio network by using the auxiliary Markov transient matrix with a failure state and a success state. And we consider the effect of symbol error for the network state(X, R) consisted of the number of transmitting PRU X and receiving PRU R. We examine the packet radio network of a continuous time Markov chain model, and the direct sequence binary phase shift keying CDMA radio channel with hard decision Viterbi decoding and bit-by-bit changing spreading code. For the unslotted distributed multi-hop packet radio network, we assume that the packet error due to a symbol error of radio channel has Poisson process, and the time period of an error occurrence is exponentially distributed. Through the throughputs which are found as a function of radio channel parameters, such as the received signal to noise ratio and chips of spreading code per symbol, and of network parameters, such as the number of PRU and offered traffic rate, it is shown that this composite analysis enables us to combine the Markovian packet radio network model with a coded DS/BPSK CDMA radio channel.