• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.7-14
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• 2010

In this paper, we introduce a hierarchical internet application traffic classification system based on SVM as an alternative overcoming the uppermost limit of the conventional methodology which is using the port number or payload information. After selecting an optimal attribute subset of the bidirectional traffic flow data collected from the campus, the proposed system classifies the internet application traffic hierarchically. The system is composed of three layers: the first layer quickly determines P2P traffic and non-P2P traffic using a SVM, the second layer classifies P2P traffics into file-sharing, messenger, and TV, based on three SVDDs. The third layer makes specific classification of the entire 16 application traffics. By classifying the internet application traffic finely or coarsely, the proposed system can guarantee an efficient system resource management, a stable network environment, a seamless bandwidth, and an appropriate QoS. Also, even a new application traffic is added, it is possible to have a system incremental updating and scalability by training only a new SVDD without retraining the whole system. We validate the performance of our approach with computer experiments.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.9
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• pp.385-396
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• 2017

Many IoT platforms have been proposed for various IoT devices, from low-end to high-end performance. We previously proposed a new IoT platform called MinT that supports the operation of the sensing devices and network communication. In the proposed platform, the things can flexibly connect to each other and efficiently share their information. Most IoT platforms, including the MinT, support thread pooling to quickly process requests. However, using a thread pool with a fixed thread count can cause network delay and inefficient energy consumption. In this paper, we propose an enhanced method to manage the thread pool efficiently by adjusting the number of threads every cycle to regulate the device's performance. In particular, we aim to improve the performance of the Interaction Thread Pool Group, which is responsible for analyzing, processing, and re-transmitting the received packets. The experiment shows that the improved method increases the average throughput by approximately 25% compared to the existing platforms. Finally, using the proposed method, the MinT can reduce the transmission delay and energy consumption of devices in the IoT environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1639-1644
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• 2016

In this paper, we consider the performance improvement that can be obtained with interference alignment (IA) technique applied to 802.11ac based multi-BSS WiFi service. To this end, we developed a system simulator consisting of a link-level PHY simulator, based on 802.11ac specification, and multi-BSS proportional-fair scheduler. Specifically, assuming perfect channel side information and synchronization of signals from multiple APs, we used a SLNR based interference alignment algorithm proposed in [13] and compared its performance with that of multiuser beamforming based time-sharing system. The performance was evaluated in terms of average throughput per BSS and 5% worst user throughput. The results show that 70 to 100% throughput gain can be obtained in this ideal scenario.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.89-95
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• 2004

CDMA is the way that more than one users can share the time and frequency at the same time and connect with multiple access in mobile communication. Multiple Access is indispensible for mobile communication because the limited frequency is able to be used by many users in mobile communication. CDMA is also applied to home network, military, business and medical sectors. This paper, presents a users should share limited frequency resource. CDMA module implemented with 8-layer PCB which consists of the Slice-board circuit, keeping Radio frequency characteristics and a slot type connector.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.63-67
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• 2014

A distributed zero-beamforming based cooperative jamming technique is useless when an eavesdropper detects the sharing seed. In addition, the currently alternatives are very limited when the eavesdropper is located nearby a source for wiretapping. This letter presents a solution to this extreme case. Relay randomly generates and transmits a binary jamming message to both source and destination in the first phase. When these two receivers securely and correctly decode the message, the source creates and transmits another message based on the use of exclusive-or for its information message and the decoded message. Consequently, the next transmission can avoid the eavesdropping.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.199-202
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• 2003

IPsec is a standardization way for protection of IP packets in network layer and it is composed of three protocols that is AH(Authentication Header), ESP(Encapsulation Security Protocol) and IKE(Internet Key Exchange). Before doing encryption and decryption using AH or ESP protocols, both of communicating entities have to share same key safely. IKE protocol works automatically. But it has less interoperability because IKE protocol is not simple. A work which standardize IKEv2 has been done up to now. In this article, we will examine the Cryptographic Algorithms of IKEv2, and describe the AES usage with IPsec, based on the IETF Draft document.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.263-264
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• 2013

기존의 도서관 정보서비스는 도서관 업무담당자에 의한 1:n 방식의 온라인 지식서비스만을 강조하였다면 스마트 도서관시스템에서는 빅데이터를 통해 지식을 생성, 검증, 분류하여 지능형지식, 실감형지식, 맞춤형지식, 체험형지식 등을 제공할 수 있다. 또한 빅데이터를 활용한 다자간 콘텐츠 공유, 상호 의견 교환이 가능하며, 집단지성에 의해 구축되는 학습 콘텐츠 및 지식 베이스는 국가의 지식자원 경쟁력을 향상시킬 수 있으며, 차세대 이러닝 환경에서의 지능형 튜터링을 통해 창의적 인재육성, 공교육의 질적 향상, 사교육비 절감, 교육 기회 균등 배분, 지역 및 계층 간 위화감 해소 등 국가정책 목표 실현할 수 있다. 제안된 빅데이터 기반의 스마트도서관 정보서비스시스템에서는 멀티테넌트 환경에서 구현이 가능한 핵심요소들을 개발하였다. 그러므로 초기 투자비용이 거의 없고, 쉽고, 간편하며, 저비용 IT 서비스가 가능한 SaaS 기반의 소프트웨어 온-디멘드 방식의 서비스 모델로 시스템을 구현하였다. 또한 연결방식으로는 N고객:1인스턴스, 제공 프로그램은 동일한 코드 사용, 커스터마이징은 고객이 테넌트별 환경 설정을 통해서 직접 수정가능, 데이터는 테넌트별 자료를 공유해서 사용할 수 있으며 기존의 디지털도서관 시스템 서비스의 단점을 해결할 수 있도록 성능을 개선하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.8-11
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• 2020

4 차 산업혁명 시대의 도래와 함께 AI, ICT 기술의 융합이 진행됨에 따라, 유저 레벨의 디바이스에서도 AI 서비스의 요청이 실현되었다. 이미지 처리와 관련된 AI 서비스는 피사체 판별, 불량품 검사, 자율주행 등에 이용되고 있으며, 특히 Deep Convolutional Neural Network (DCNN)은 이미지의 특색을 파악하는 데 뛰어난 성능을 보여준다. 하지만, 이미지의 크기가 커지고, 신경망이 깊어짐에 따라 연산 처리에 있어 낮은 데이터 지역성과 빈번한 메모리 참조를 야기했다. 이에 따라, 기존의 계층적 시스템 구조는 DCNN 을 scalable 하고 빠르게 처리하는 데 한계를 보인다. 본 연구에서는 DCNN 의 scalable 하고 빠른 처리를 위해 3 차원 메모리 구조의 Processing-In-Memory (PIM) 가속기를 제안한다. 이를 위해 기존 3 차원 메모리인 Hybrid Memory Cube (HMC)에 하드웨어 및 소프트웨어 모듈을 추가로 구성하였다. 구체적으로, Processing Element (PE)간 데이터를 공유할 수 있는 공유 캐시 및 소프트웨어 스택, 파이프라인화된 곱셈기 및 듀얼 프리페치 버퍼를 구성하였다. 이를 유명 DCNN 알고리즘 LeNet, AlexNet, ZFNet, VGGNet, GoogleNet, RestNet 에 대해 성능 평가를 진행한 결과 기존 HMC 대비 40.3%의 속도 향상을 29.4%의 대역폭 향상을 보였다.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.29-38
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• 2012

As smart convergence occurs, solving the digital divide issue for weak layers such as the elderly, handicapped and poor groups is becoming an emerging issue. This study aims to promote information service to encourage active participation of the weak layers and to bridge the digital divide among those under the digital switchover and the smart phone convergence environments. This study, comparing the environments of Korea and other major countries with respect to digital divide, found some differences and tried to suggest proper policies for Korea to remain as a leading IT country. We expect this study to help the government, industries, schools cope with the divide issues and establish proper policies to provide weak layers with equal opportunities to IT in the coming smart convergence era.

• Archives of design research
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• v.18 no.1 s.59
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• pp.215-222
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• 2005

Gaining information via the internet is becoming pivotal in today's society as the internet is becoming the center of knowledge and information. The goal of this study is to present the guideline of web interface design for the elderly who are alienated in gaining information from the Internet. If the internet were more user friendly to the elderly, they would be able to spend more time in doing what they enjoy and also in self development, with the information gained on the internet. This study investigated current portal sites to understand the present situation, surveyed and interviewed the elderly, and researched literatures on how the elderly perceive various stimulants and also researched documents for previous guidelines on interface design for them. This study investigated internet sites which the elderly use to gather information about products and which entice their purchasing desires. The conclusion is that the usability can be improved by eliminating visual dizzy elements in the pages, simplifying the layout and the menu designs which represent the information architecture.