• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.899-902
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• 2004

임베디드 시스템은 현재 가전, 단말, 제어, 통신등 다양한 분야에서 응용되고 있으며 컴퓨터 관련 기술의 발전과 더불어 응용분야는 더욱 넓어질 것이다. 이러한 임베디드 시스템의 관리나 테스트를 위해 모니터링 프로그램이 필요하다. 임베디드 시스템은 일반 PC 시스템과 달리 많은 제약을 가지고 있다. 본 논문에서는 자원적 제약을 가진 임베디드에 활용되어지는 NFS를 이용한 임베디드 장비 모니터링에 적합한 MONETA(distributed MONitoring for Embedded TArget system)를 설계, 구현하였다. MONETA에서 제시하는 구조는 모니터링을 위한 서버, 모니터링하는 대상인 클라이언트, 시스템 사용자의 3계층 구조의 분산 모니터링 시스템으로 각 장비별 CPU, Moemory, Disk, 트래픽량을 그래프로 나타도록 구현된다.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.135-140
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• 2015

The WDSS improves defensive capacity against web application layer DDoS attack by using web cache server and L7 switch which are added on the DDoS shelter system. When web DDoS attack occurs, security agents divert traffic from backbone network to sub-network of the WDSS and then DDoS protection device and L7 switch block abnormal packets. In the meantime, web cache server responds only to requests of normal clients and maintains stable web service. In this way, the WDSS can counteract the web DDoS attack which generates small traffic and depletes server-client session resource. Furthermore, the WDSS does not require IP tunneling because it is not necessary to retransfer the normal requests to original web server. In this paper, we validate operation of the WDSS and verify defensive capability against web application layer DDoS attacks. In order to do this, we built the WDSS on backbone network of an ISP. And we performed web DDoS tests by using a testing system that consists of zombie PCs. The tests were performed by three types and various amounts of web DDoS attacks. Test results suggest that the WDSS can detect small traffic of the web DDoS attacks which do not have repeat flow whereas the formal DDoS shelter system cannot.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1914-1924
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• 2016

In this paper, considering virtualized Evolved Packet Core(vEPC) network for 5G mobile network, we propose architecture for supporting Service Function Chaining(SFC) in 5G mobile network. Using SFC in 5G network, dynamic path configuration and providing network services based on subscriber and traffic information. SFC technology provides logical ordered set of network functions and delivers packet through providing logical path over the physical network. Based on the perspective of 5G core network in distributed manner, we design hierarchical SFC architecture to manage SFC for global path including vEPC and SGi-LAN network, and internal path between virtualized network functions in each cloud. In this paper, we define architecture and call flow for establishing data path using SFC. Finally, we design testbed architecture for real implementation based on open source software.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.191-201
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• 2023

As Edutech arises which is integrating IT technology into education, many related attempts have been tried on music education area. The focus has been shifted from the teachers to the learners, and this makes the personalized learning emerge. The learner's proficiency is an essential factor to support the personalized learning. The chord fingering is an important technique in piano learning. In this paper, a personalized learning tool for piano chords has been suggested. And then, several utilization ways have been described by analyzing the chords patterns. Specifically, the difficulty of the chords and the proficiency of the learner are derived from the accumulated practicing log data of the users. More effective learning way of the chords has been presented through hierarchical clustering based on chords similarity. Furthermore, the suggested approach where only the practicing log data are used lessens the learner's burden to measure the proficiency and the chord's difficulty without additional efforts like taking tests.

• Advanced Industrial SCIence
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• v.2 no.3
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• pp.8-14
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• 2023

The majority of IoT devices already employ AIoT, however there are still numerous issues that need to be resolved before AI applications can be deployed. In order to more effectively distribute IoT edge resources, this paper propose a machine learning-based approach to managing IoT edge resources. The suggested method constantly improves the allocation of IoT resources by identifying IoT edge resource trends using machine learning. IoT resources that have been optimized make use of machine learning convolution to reliably sustain IoT edge resources that are always changing. By storing each machine learning-based IoT edge resource as a hash value alongside the resource of the previous pattern, the suggested approach effectively verifies the resource as an attack pattern in a distributed AIoT context. Experimental results evaluate energy efficiency in three different test scenarios to verify the integrity of IoT Edge resources to see if they work well in complex environments with heterogeneous computational hardware.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.105-109
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• 2006

Hypercube has a regular and hierarchical structure, therefore it can be applied to the development of efficient diagnosis algorithm. Kranakis and Pelc [7] have proposed HYP-DIAG algorithm to implement different method of HADA/IHADA and adaptive cube partition method after embedding the small size of ring that includes all the faulty nodes. In this paper, we propose new method to reduce testing rounds by analyzing the syndrome of RGC-rings gained in the first step of HYP-DIAG and analyze the proposed algorithm.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.2
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• pp.114-124
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• 2009

In this paper, we propose a practical TCP friendly rate control scheme that considers the minimum channel bandwidth of the network when transporting SVC (scalable video coding) video over IP netowrks such as Internet. RTP and RTCP is mainly designed for use with UDP (User Datagram Protocol) for real-time video transport over the Internet. TCP-friendly rate control was proposed to satisfy the demands of multimedia applications while being reasonably fair when competing for bandwidth with conventional TCP applications. However the rate control model of the conventional TCP-friendly rate control scheme does not consider the minimum channel bandwidth of the network. Thus the estimated channel bandwidth by the conventional rate control model might be quite different from the real channel bandwidth when the packet loss ratio of the network is very large. In this paper, we propose a modified TCP-friendly rate control scheme that considers the minimum channel bandwidth of the network. Based on the modified TCP-friendly rate control, we assign the minimum channel bandwidth to the base layer bitstream of SVC video, and remaining available bandwidth is allocated to the enhancement layer of SVC video for the TCP friendly scalable video transmission. It is shown by simulations that the modified TCP-friendly rate control scheme can be effectively used for a wider range of controlled bit rates depending on the packet loss ratio than the conventional TCP-friendly control scheme. Furthermore, the effectiveness of the proposed scheme in terms of objective video quality is proved by comparing PSNR performance with the conventional scheme.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.50-56
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• 2010

Supervisory Control and Data Acquisition Systems (SCADAs) is real-time monitor and control systems. SCADA systems are used to monitor or control chemical and transportation processes, in municipal water supply systems, electric power generation, transmission and distribution, gas and oil pipelines, and other distributed processes. SCADA refers to a large-scale distributed system. The supervisory control system is placed on top of a real time control system to control external processes. Emerging security technologies and security devices are decreasing the vulnerability of the power system against cyber threats. Dealing with these threats and analyzing vulnerabilities is an important task for equipment such as RTU, IED and FEP. To reduce such risks, we develop such a SCADA testbed. This paper presents the development of a testbed designed to assess the vulnerabilities SCADA networks(including serial communication).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.57-65
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• 2007

The overlay multicast that has been recently presented as IP alternative for the IP multicast has been getting much persuasion by the computing power of the hardware and the advancement of the network techniques to enforce Routing in application-level. In an overlay multicast, the system resource and the network bandwidth must be utilized efficiently to service real-time HDTV images. Specifically, the system must consider the delay and the jitter that can be incurred at the application-level. In this paper, we implement a server and a client to broadcast HDTV, in the session composed by the existing overlay multicast protocol. The broadcasting server performs the service using a TV tuner, An HDTV camcorder, and files, clients constituting a multicast group relay the received data to other clients. At this time, the information that the clients report periodically, including their delay and the network state, to the server is used as an important information to maintain an overlay session. The implementation is based on the DirectX and its performance is evaluated by the LAN test bed that has been set.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1213-1220
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• 2011

In this paper, a new ensemble system using dynamic weighting method with added weight information into classifiers is proposed. The weights used in the traditional ensemble system are those after the training phase. Once extracted, the weights in the traditional ensemble system remain fixed regardless of the test data set. One way to circumvent this problem in the gating networks is to update the weights dynamically by adding processes making architectural hierarchies, but it has the drawback of added processes. A simple method to update weights dynamically, without added processes, is proposed, which can be applied to the already established ensemble system without much of the architectural modification. Experiment shows that this method performs better than AdaBoost.