• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.8
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• pp.615-622
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• 2013

Fast and accurate signature extraction is essential to improve the performance of the payload signature-based traffic analysis methods. However the slow manual process in extracting signatures make difficult to deal with the rapidly changing application in current Internet environment. Therefore, in this paper we propose a system automatically generating signatures from ground-truth traffic data. In addition, we improve the efficiency of signature extraction by recognizing the application protocol using a protocol filters and generating signatures automatically according to the application-specific protocol contents. In order to verify the validity of the system proposed in this paper, we compared the signatures automatically generated from our system with the signatures manually created for a few popular applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.3026-3045
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• 2012

In this paper, diversity-multiplexing tradeoff (DMT) of three-user wireless multiple-antenna cooperative systems is investigated in general fading channels when half-duplex and decode-and-forward relay is employed. Three protocols, i.e., adaptive protocol, receive diversity protocol, and dual-hop relaying protocol, are considered. The general fading channels may include transmit and/or receive correlation and nonzero channel means, and are extensions of independent and identically distributed Rayleigh or Rician fading channels. Firstly, simple DMT expressions are derived for general fading channels with zero channel means and no correlation when users employ arbitrary number of antennas. Explicit DMT expressions are also obtained when all users employ the same number of antennas and the channels between any two users are of the same fading statistics. Finally, the impact of nonzero channel means and/or correlation on DMT is evaluated. It is revealed theoretically that the DMTs depend on the number of antennas at each user, channel means (except for Rayleigh and Rician fading statistics), transmit and/or receive correlation, and the polynomial behavior near zero of the channel gain probability density function. Examples are also provided to illustrate the analysis and results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.464-472
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• 2011

As wireless sensor networks are applied to various applications such as environment monitoring and disaster sensing system, there are increased needs for wireless communication in underground environment. Since the previous wireless communication technology using electromagnetic wave is not appropriate for the underground environment, a new alternative is required. Recently a magnetic field communication technology has been proposed and standardized as a domestic KS standard. In this paper, we analyze the media access control protocol of the KS standard by an analysis and a simulation study.

• International Journal of Contents
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• v.10 no.2
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• pp.9-17
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• 2014

Since vehicles' trajectories are so complex and dense traffic changes in nature frequently, the VANET (Vehicles Ad-hoc Network), using Omni-directional Antenna, has many channel collisions (or overlapping) on Data Link phrases (MAC layers). It is not easy to keep a good seamless communication status for VANET because of its unpredictable network environment. Among VANET research, Directional Antenna have been proposed as one of the most common systematical solutions to reduce (or to mitigate) this miss-communication problems by narrowing communicational ranges and making use of its customized error-detection process. However, even though Directional Antennas help VANET keep good seamless communication, many VANET researchers have reported that Directional VANET still has miss-communicational problems - this has lead to problems like 'Directional Hidden Terminal Problem', 'Deafness', 'Un-accuracy Lobe Scopes' and 'High Deployment Cost' being reported in various papers. To establish well-organized design assessments for a good Directional VANET MAC protocol to overcome these problems, we rearranged and grouped current Directional VANET' qualitative criteria from several current survey papers using these categories- 'Directional Discovery', 'Directional Forwarding' and 'Directional Handover'. In addition, based on the results of the following analysis, we show the essential design concerns that need to be looked at in order to develop a well-designed Directional-VANET MAC protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1323-1332
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• 2005

EAP (Extensible authentication protocol) is a sort of general framework for authentication rather than a specific authentication protocol. An important consequence of this is that EAP can accommodate a variety of authentication/key-establishment protocols for different internet access networks possibly integrated to a common IP core network This paper tries a comparative analysis of several specific authentication/key establishment protocols for EAP, and suggest a strategic viewpoint toward the question: which one to un. In addition, we tried to make things clear about an intellectual property right issue with regard to some password-based protocols.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.1031-1038
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• 2005

In this paper, the maximum traffic quantity and actual traffic quantify of the data which are needed to grasp the statement of a system will be measured more accurately. A concrete quality measurement will be conducted by analysing a change of traffic quantity according to a protocol change and traffic under an overload condition when there is an accident. As a result can make an opportunity to maximize safety of power SCADA. Furthermore, future traffic quantity can be prospected by knowing current traffic quantity and grasping the rate of increase by the analysis and the information can be used as data to secure the band width in advance. It can make stable operation of power SCADA by arranging the limited network resources efficiently by information analysis of a network and expects more confidence.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.635-644
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• 2002

We propose the PBSM(Protocol-Based Security Module) system which guarantees the secure data transmission under web environments. There are two modules in the PBSM architecture. One is Web Server Security Module(WSSM) which is working on a web server, the other is the Winsock Client Security Module(WSCSM) which is working on a client. The WSCSM security module decrypts the encrypted HTML document that is received from the security web server. The decrypted HTML document is displayed on the screen of a client. The WSSM module contains the encryption function for HTML file and the decryption function for CGI(Common Gateway Interface). The formal analysis methodology is imported from format theory for analyzing the data flow of the PBSM system. The formal analysis methodology is based on the order theory.

• ETRI Journal
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• v.33 no.3
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• pp.382-392
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• 2011

This paper proposes the streaming radio frequency identification (RFID) protocol to support robust data streaming in a passive communication, which is extended from the ISO18000-6 Type C RFID standard. By observing and modeling the unique bit error behavior through detailed analysis in this paper, we found that performance is significantly limited by inaccurate and unstable link frequencies as well as low SNR which are inevitable for passive devices. Based on the analysis, we propose a simple and efficient protocol to adaptively insert extra error control sequences in a packet for tolerating tough link condition while maximizing the throughput and preserving the minimal implementation cost. To evaluate effectiveness of our proposal in real-time streaming applications, we experimented on real-time H.264 video streaming and prototyped the system on FPGA. To our best knowledge, our paper is the first work to take analytical approach for maximizing the throughput and demonstrate the possibility of the realtime multimedia streaming transmission in the passive RFID system.

• Journal of the Korea Society for Simulation
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• v.16 no.1
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• pp.59-68
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• 2007

IT (Intrusion Tolerant) technology is for guaranteeing the availability of service for certain amount time against the attacks which couldn't be prevented by the currently deployed information security countermeasures. IT (Intrusion Tolerant) technology mainly makes use of the replication of service and system fur enhancing availability, and voting scheme and GMP (Croup Management Protocol) are used for the correctness of service. This paper presents a scheme to analyze dependability of IT (Intrusion Tolerant) technology through probabilistic and simulation method. Using suggested analysis scheme, we can analyze the robustness and make a sensible trade-offs in of IT (Intrusion Tolerant) technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.7
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• pp.602-617
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• 1990

In this paper, we analyze the performance of D-channel access protocol at the S-reference point for the ISDN user network interface recommended by CCITT. For the case of multipoint access to D-channel, a queueing model of D-channel access protocol is proposed. The delay is analyzed by decomposing it into waiting queue delay and contention delay. The contention delay is decomposed further into vain contention delay and pure contention delay so the analysis of the priority queueing system with symmetrical and asymmetrical arrival rates may be applied. The numerical results obtained are compared with the results of the single station queueing system served by the non-preemptive priority.