• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.317-326
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• 2010

Nowadays, transmission bandwidth for network traffic is increasing and the type is varied such as peer-to-peer (PZP), real-time video, and so on, because distributed computing environment is spread and various network-based applications are developed. However, as PZP traffic occupies much volume among Internet backbone traffics, transmission bandwidth and quality of service(QoS) of other network applications such as web, ftp, and real-time video cannot be guaranteed. In previous research, the port-based technique which checks well-known port number and the Deep Packet Inspection(DPI) technique which checks the payload of packets were suggested for solving the problem of the P2P traffics, however there were difficulties to apply those methods to detection of P2P traffics because P2P applications are not used well-known port number and payload of packets may be encrypted. A proposed algorithm for identifying P2P heavy traffics based on flow transport parameters and behavioral characteristics can solve the problem of the port-based technique and the DPI technique. The focus of this paper is to identify P2P heavy traffic flows rather than all P2P traffics. P2P traffics are consist of two steps i)searching the opposite peer which have some contents ii) downloading the contents from one or more peers. We define P2P flow patterns on these P2P applications' features and then implement the system to classify P2P heavy traffics.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.231-243
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• 2009

Many DSP systems are streaming applications in which streams of data constantly flow through a set of filters. Dataflow programming paradigm is one of effective methods for representing these streaming applications. Dataflow programming model explicitly exposes parallelisms within an application, which helps compiling of the application onto a multicore platform. We propose SPEX(Signal Processing Extension), a language extension to a standard imperative language based on the parameterized dataflow model. Parameterized dataflow model is a kind of dataflow model that can express a modest fashion of dynamism contrary to the synchronous dataflow that can represent only static dataflow. SPEX facilitates characterizing an application written in conventional imperative languages such C/C++ as a streaming application. SPEX is comprised of a few keywords augmented to the conventional C++ syntax for representing dataflow paradigm. SPEX also restricts the syntax and semantics of C++ in order to fit the program within a certain streaming programming category. In this paper, we focus on the capability of SPEX in representing streaming computations within filters and streaming communications among filters.

• Proceedings of the Korea Database Society Conference
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• 2008.05a
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• pp.359-368
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• 2008

Although the important information are significantly increasing in the Web, it is easily disappeared because of the Web's characteristics. The purpose of this paper is researching and developing of base technology for archiving web records. First developing about the workflow which is the procedure of web archiving, and developing about metadata elements, the essential condition of preserving web records and accessing archived resources. Finally developing the architecture defined the overall items of web records archiving.

• Archives of design research
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• v.19 no.2 s.64
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• pp.229-240
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• 2006

It is very important issue in information design to improve information efficiency by adapting interesting factors in changing circumstance of information communication. The concept of infotainment is utilized in designing information contents in a way of combining entertainment factors with information itself based on various media and representation technologies. The information arousing user's attention, which includes interesting factors, is persuasive message comppared to the informative message conveying only information itself. The reason why infotainment is persuasive is because it makes the user absorb deeply in the information during the process of understanding by sensorial stimuli, cognitive interest, and situational interest. The sensorial stimuli originates from the expression elements of information design. The cognitive interest from the user's intellectual activities has a try to overcome mental block when user confronts with the redundant expression in the manner of unexpectedness and inharmony. The situational interest originates from user's optimum experience by the flow of satisfaction. Therefore, the attribute of infotainment is defined with the stimuli, the redundancy, and user's satisfaction. Its design elements consist of physical factors, organizational factors, and psychological factors. The physical factors through sensorial stimuli are utilized by visual manipulation such as visual analogy or visual pun, multimedia, and moving expression. The organizational factors through redundant expression bring user's imagination by adapting storytelling, event, and interaction in the process of understanding information. The psychological factors through expression of entertainment interests such as humor, play, and game give users psychological satisfaction with the flow. In conclusion the concept of infotainment can be adapted when the design factors should be integrated with its attributes, or the conveying information should go well with its purpose and characteristics.

• Journal of IKEEE
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• v.23 no.1
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• pp.280-288
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• 2019

In the CR-enabled MANET, routing paths can be easily destroyed due to node mobility and channel unavailability (due to the emergence of the PU of a channel), resulting in significant overhead to maintain/recover the routing path. In this paper, network caching is actively used for route maintenance, taking into account the properties of the CR. In the proposed scheme, even if a node detects that a path becomes unavailable, it does not generate control messages to establish an alternative path. Instead, the node stores the packets in its local cache and 1) waits for a certain amount of time for the PU to disappear; 2) waits for a little longer while overhearing messages from other flow; 3) after that, the node applies local route recovery process or delay tolerant forwarding strategy. According to the simulation study using the OPNET simulator, it is shown that the proposed scheme successfully reduces the amount of control messages for path recovery and the service latency for the time-sensitive traffic by 13.8% and 45.4%, respectively, compared to the existing scheme. Nevertheless, the delivery ratio of the time-insensitive traffic is improved 14.5% in the proposed scheme.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.1
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• pp.23-34
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• 2022

With the development of network technology, the application area has also been diversified, and protocols for various purposes have been developed and the amount of traffic has exploded. Therefore, it is difficult for the network administrator to meet the stability and security standards of the network with the existing traditional switching and routing methods. Software Defined Networking (SDN) is a new networking paradigm proposed to solve this problem. SDN enables efficient network management by programming network operations. This has the advantage that network administrators can flexibly respond to various types of attacks. In this paper, we design a threat level management module, an attack detection module, a packet statistics module, and a flow rule generator that collects attack information through the controller and switch, which are components of SDN, and detects attacks based on these attributes of SDN. It proposes a method to block denial of service attacks (DoS) of advanced attackers by programming and applying honeypot. In the proposed system, the attack packet can be quickly delivered to the honeypot according to the modifiable flow rule, and the honeypot that received the attack packets analyzed the intelligent attack pattern based on this. According to the analysis results, the attack detection module and the threat level management module are adjusted to respond to intelligent attacks. The performance and feasibility of the proposed system was shown by actually implementing the proposed system, performing intelligent attacks with various attack patterns and attack levels, and checking the attack detection rate compared to the existing system.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.99-107
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• 2018

In this study, the injector transfer function (ITF) of a gas-gas coaxial jet-swirl injector is measured by perturbing jet or swirl flow using a speaker as jet flow increases. As a result of measuring the ITF varying feed system length, a peak occurs at a resonance frequency of space where the perturbed flow passes. With jet excitation, the ITF magnitude decreases, but increases thereafter as increasing the jet flow. Therefore the larger the velocity difference between jet and swirl flow, the larger the ITF. With swirl excitation, ITF decreases as increasing the jet flow because of the energy decrease with respect to the constant downstream flow.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.97-105
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• 2019

The tactical mobile ad-hoc network(MANET) consists of distributed autonomous networks between individual ground nodes, which is effective in terms of network survivability and flexibility. However, due to constraints such as limited power, terrain, and mobility, frequent link disconnection and shadow area may occur in communication. On the other hand, the satellite network has the advantage of providing a wide-area wireless link overcoming terrain and mobility, but has limited bandwidth and high-latency characteristic. In the future battlefield, an integrated network architecture for interworking multi-layer networks through a heterogeneous network gateway (HNG) is required to overcome the limitations of the existing individual networks and increase reliability and efficiency of communication. In this paper, we propose a new HNG architecture and detailed algorithm that integrates satellite network and the tactical MANET and enables reliable data transfer based on flow characteristics of traffic. The simulations validated the proposed architecture using Riverbed Modeler, a network-level simulator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.575-577
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• 2013

The research was aimed at the hotel industry's employees in order to test the efficiency of e-Learning, which is emerging as the alternative training system to the conventional one. The independent variables are the quality of e-Learning, including the qualities of the system, contents, and service of e-Learning, and the learning characteristic factor, including the quality factor of e-Learning, the self-efficacy of the user, learning motivation, and the flow of learning. Furthermore, the intervening variables are its perceived usefulness and the satisfaction factor of the user known as the so-called utility of e-Learning, continuous intention to use in terms of efficaciousness, and the spread of education and training. The dependent variable is customer orientation, known as the ultimate efficaciousness of corporate e-Learning.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.691-698
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• 2017

In this study, the injector transfer function (ITF) of a gas-gas coaxial jet-swirl injector is measured by applying excitation to jet or swirl flow using a loudspeaker. As a result of measuring the ITF according to the variation of feed system length, the ITF peak occurs at the resonance frequency of the space where the perturbed flow passes. When applying the excitation to the jet flow, as the jet flow increases up to 56 slpm, the magnitude of ITF decreases, and ITF increases thereafter. Therefore the larger the velocity difference between the jet and the swirl flow, the larger the ITF. In the case of the swirl excitation, the ITF decreases as the jet flow increases because of the decrease of the energy with respect to the constant flow at the downstream. This difference is caused by the location of the hot wire anemometer on the downstream of the injector center axis.