• Journal of Korea Multimedia Society
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• v.17 no.8
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• pp.988-994
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• 2014

Software Defined Network (SDN) is a new technology in computer network area which enables user to centralize control plane. The security issue is important in computer network to protect system from attackers. SYN flooding attack is one of Distributed Denial of Service attack methods which are popular to degrade availability of targeted service on Internet. There are many methods to protect system from attackers, i.e. firewall and IDS. Even though firewall is designed to protect network system, but it cannot mitigate DDoS attack well because it is not designed to do so. To improve performance of DDOS mitigation we utilize another mechanism by using SDN technology such as OpenFlow and sFlow. The methodology of sFlow to detect attacker is by capturing and sum cumulative traffic from each agent to send to sFlow collector to analyze. When sFlow collector detect some traffics as attacker, OpenFlow controller will modify the rule in OpenFlow table to mitigate attacks by blocking attack traffic. Hence, by combining sum cumulative traffic use sFlow and blocking traffic use OpenFlow we can detect and mitigate SYN flooding attack quickly and cheaply.

• Journal of the Korea society of information convergence
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• v.5 no.2
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• pp.67-76
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• 2012

XML-based open protocol, XMPP users to pass messages to other users, which means that a decentralized communication network is the network infrastructure and enable it. In addition, XMPP servers using a professional server-to-server protocol to communicate with each other and decentralized social networks and collaboration framework provides an important possibility. In this paper, the features of XMPP messaging protocol is applicable to automotive telematics terminals XMPP-based platform design, and presence of two-way communication point for the problem, point-to-point session setup issues, security issues, compatibility issues, and to solve the scalability problem XMPP-based messaging system was implemented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.398-403
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• 2006

In this paper, we describe a fuzzy threshold selection technique for feature extraction in digital color images. this is achieved by the formulation a fuzzy inference system that evaluates threshold for feature configurations. The system uses two fuzzy measures. They capture desirable characteristics of features such as dependency of local intensity and continuity in an image. We give a graphical description of a nonlinear sketch feature extraction filter and design the fuzzy inference system in terms of the characteristics of the feature. Through the design, we provide selection method on the choice of a threshold to achieve certain characteristics of the extracted features. Experimental results show the usefulness of our fuzzy threshold inference approach which is able to extract features without human intervention.

• Journal of Internet Computing and Services
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• v.2 no.5
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• pp.41-47
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• 2001

This paper deals with an EJB-based database agent(component) used to define workflow processes, which is a core function of the e-Chautauqua workflow management system that is an on-going research product. We describe about how to design and implement the EJB-based DB agent that is deployed on EJB server as a component. The agent is located between the build-time clients and the database system, and manages database accesses, such as retrieves and stores, from the workflow definition components. Through the EJB technology, we are able to accomplish a stable database agent that can be characterized by the distributed object management, reliable recovery mechanism from system failovers, reliable large-scale transaction management, and the security functions.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.41-46
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• 2012

Visible light communication(VLC) system based on LED devices has some specific advantages compared with RF system. First, visible light is harmless to human and there is no limit to using frequency band. Also, VLC system has good security performance, and it can use the very wide frequency band for data transmission. However, for simultaneously using the illumination and data transmission in VLC systems, degradation of code rate is occurred. So, in this paper, we proposed the novel line coding scheme for flicker free and efficient dimming control in VLC systems. From the simulation results, it is confirmed that proposed scheme has good flicker, dimming, and transmission performance compared to conventional variable pulse position modulation(VPPM) scheme.

• Journal of Digital Contents Society
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• v.4 no.1
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• pp.1-10
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• 2003

This research focuses on the system design of a service method for a customized electronic card on the internet. It develops the system which covers from the input stage of the credit information including a credit card number, a debit card number, and a bank account number, through the process of decision for issuing the customized electronic card and for the payment of business transaction, to the payment stage. Users are allowed to make their own customized card depending on their situations by choosing a limit of balance, a number of usage, expiration date, recharge, and, anonymity of electronic card on the internet. These characteristics enhances convenience and security of card users. In addition, user's financial damage can be minimized when a credit card is lost by any reason.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.352-356
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• 2005

Content management, distribution system and DRM technology have been developed respectively, many contents services are more focused on the system like stability of distribution system or contents security than user-orient. In this paper, we would suggest multimedia contents management based on DRM and distribution model for the users of massive multimedia. The suggested model will be a total solution of content management, DRM and Watermarking functions as well as it will offer convenience to the users with Indexing DBMS which is focused on users.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.134-143
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• 2017

Machine fault diagnosis recovers all the studies that aim to detect automatically faults or damages on machines. Generally, it is very difficult to diagnose a machine fault by conventional methods based on mathematical models because of the complexity of the real world systems and the obvious existence of nonlinear factors. This study develops an automatic machine fault diagnosis system that uses pattern recognition techniques such as principal component analysis (PCA) and artificial neural networks (ANN). The sounds emitted by the operating machine, a drill in this case, are obtained and analyzed for the different operating conditions. The specific machine conditions considered in this research are the undamaged drill and the defected drill with wear. Principal component analysis is first used to reduce the dimensionality of the original sound data. The first principal components are then used as the inputs of a neural network based classifier to separate normal and defected drill sound data. The results show that the proposed PCA-ANN method can be used for the sounds based automated diagnosis system.

• Journal of Korean Academy of Nursing Administration
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• v.12 no.3
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• pp.373-384
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• 2006

Purpose: This is a pilot study to identify patient safety risk factors and strategies for patient safety management perceived by nurses. Methods: Data were collected and analyzed with an open questionnaire from April to May 2005, targeted on 100 nurses working in two hospitals. The issues were 'what are risk factors for patients, nurses, and other medical practitioners? How do they prevent with the aftermath of risk factors, causes of incidents?' For data analysis, types and frequency of risk factors were worked out, using the Australian Incident Monitoring System Taxonomy. Results: The types of patient safety risk factor perceived by nurses were as follows ; therapeutic devices or equipment, infrastructure and services (29.5%), nosocomial infections (16.3%), clinical processes or procedures (15.4%), behavior, human performance, violence, aggression, security and safety (12.2%), therapeutic agents (9.7%), injuries and pressure ulcers (8.7%), logistics, organization, documentation, and infrastructure technology (5.6%). Strategies for patient safety included training of prevention of infection, education about safety management for patients and medical professionals, establishment of reporting system, culture of care, pre-elimination of risk factors, cooperative system among employees, and sharing information. Conclusion: These results will be used to provide evidences for patient safety management and educational program.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.59-69
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• 2006

Generally, network attacks are based on a scenario composed of a series of single-attacks, scenario attacks are launched over a wide network environment and their targets are not apparent. it is required to analyze entire packets captured on the network. This method makes it difficult to detect accurate patterns of attacks because it unnecessarily analyzes even packets unrelated to attacks. In this paper, we design and implement a simulation system for attacks scenario, which helps packet classification connected with attacks. The proposed system constitutes a target network for analysis in a virtual simulation environment, and it simulates dumping TCPDUMP packets including scenario attacks under the constructed virtual environment, We believe that our proposed simulation system will be a useful tool when security administrators perform the analysis of patterns of attack scenarios.