• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.335-339
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• 2003

We proposed a Web cache replacement technique of a divided scope base that considered a size reference characteristics of a Web object for efficient operation of a Web base system and, in this study, analyzed performance of the replacement technique that proposed it though an experiment. We analyzed a reference characteristics of size to occur by a user reference characteristics through log analysis of a Web Base system in an experiment. And we divide storage scope of a cache server as its analysis result and tested this replacement technique based n divided scope. The proposed technique has a flexibility about a change of a reference characteristics of a user. Also, experiment result, we compared it with LRU and the LRUMIN which were an existing replacement technique and confirmed an elevation of an object hit ratio.

• Journal of Korea Multimedia Society
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• v.18 no.10
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• pp.1172-1179
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• 2015

A wireless license plate region extracting module is proposed for LPR system controlling multiple gates. This module is cheaply implemented using Raspberry Pi which is open source and high performance. First, as the upper 1/3 of the captured image is discarded as it has no useful information on license plate. Using the OpenCV libraries the edge image is got by Canny algorithm after applying Gaussian filtering to gray image, and the labeling is conducted for 4 consecutive numbers in license plate. These numbers are located using various decision equations, and expanding the numbers region the final license plate region can be extracted. The result image is transferred to Server using wifi direct. Using the proposed module it becomes easy to set up and maintain the LPR system. The experimental results showed that the successful extracting rate was 98.4% using 500 car images with 640 × 480 resolution.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.235-237
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• 2001

본 논문의 웹 서버 디렉터는 웹 서버의 앞단에 설치되어 과부하 상태에서 서버의 성능 감소를 막는 역할을 한다. 본 논문을 통해 구현된 웹 서버 디렉터는 기존의 아파치와 같은 웹 서버의 수정 없이 그대로 사용하기 때문에, 그 동안 개발되어 온 웹 서버 모듈과 부가 기능을 모두 사용할 수 있는 장점이 있다. 또한, 서버의 I/O 모델로 가장 이상적이라고 검증된 단일 프로세스와 이산사건처리 방식을 채택하여, 일반 웹 서버에 비하여 최고 1.6배의 성능 향상을 보인다 부가적으로 SYN Flooding 과 같은 악의적인 웹 요청에도 견고한 특성을 보인다.

• Journal of information and communication convergence engineering
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• v.18 no.2
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• pp.100-105
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• 2020

With the advent of the 5G era, the rapid growth in demand for mobile content services has increased the need for additional backhaul investment. To meet this demand, employing a content delivery network (CDN) and optical access solution near the last mile has become essential for the configuration of 5G networks. In this paper, a cache-enabled architecture using the passive optical network (PON) is presented to serve video on demand (VoD) for users. For efficient use of mobile backhaul, I propose a request deduplication scheme (RDS) that can provide all the requested services missed in cache with minimum bandwidth by eliminating duplicate requests for movies within tolerable range of the quality of service (QoS). The performance of the proposed architecture is compared with and without RDS in terms of the number of requests arriving at the origin server (OS), hit ratio, and improvement ratio according to user requests and cache sizes.

• Journal of Computing Science and Engineering
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• v.5 no.4
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• pp.283-287
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• 2011

Due to the proliferation of software parallelization on multi-core CPUs, the number of concurrently executing processes is rapidly increasing. Unlike processes running in a server environment, those executing in a multi-core desktop or a multi-core mobile platform have various correlations. Therefore, it is crucial to consider correlations among concurrently running processes. In this paper, we exploit the property that for a given created location in the binary image of the parent process, the average running time of child processes residing in the run-queue differs. We claim that this property can be exploited to improve the overall system performance by running processes that have a relatively short running time before those with a longer running time. Experimental results verified that the running time was actually improved by 11%.

• Annual Conference of KIPS
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• 2003.11a
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• pp.127-130
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• 2003

웹 클러스터 시스템은 인터넷에서 요청되는 부하를 여러 실제 서버들에게 분산시켜서 어플리케이션에 따른 처리와 응답을 하는 서버 단 시스템이다. 부하는 서비스를 제공하는 서비스에 따라 다른 성향을 띄게 되므로 서비스 제공자는 부하의 특성을 파악하여 알맞은 웹 클러스터 시스템을 사용하여야 효율적이고 좋은 성능을 보이게 된다. 이 논문에서는 7 개의 다른 성향의 부하 상황과 Alteon Web Switch, ALBM Traffic Manager와 Linux Virtual Server를 사용하여 클러스터를 구성하고 각 부하 상황에서 클러스터 시스템들이 어떤 성능을 보여주는지 비교 분석한다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1553-1557
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• 2005

High performance and reliability of the storage system to handle a very large amount of data has been become very important. Many techniques have been applied on the various application systems to establish very large capacity storage that satisfy the requirement of high I/O speed and physical or logical failure protection. We applied RAID and LVM to construct a storage system for the global data center which needs a very reliable large capacity storage system. The storage system is successfully established and equipped on the latest Linux application server.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.168-174
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• 2010

User authentication is an important requirement to provide secure network service. Therefore, many authentication schemes have been proposed to provide secure authentication, such as key agreement and anonymity. However, authority of scheme is limited to one's self. It is inefficient when authenticated users grant a certification to other users who are in an organization which has a hierarchical structure, such as a company or school. In this paper, we propose the first authentication scheme to use Attributes-Based Re-encryption that creates a certification to other users with specified attributes. The scheme, which has expanded from Rhee et al. scheme, has optimized computation performance on a smart card, ensuring the user's anonymity and key agreement between users and server.

• Journal of the Korean Data and Information Science Society
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• v.18 no.1
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• pp.107-121
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• 2007

An efficient encoding algorithm (or encryption algorithm) is essential for mobile devices since their resources such as computation power and battery capacity are very limited. This study is to propose an efficient encoding scheme for protecting mobile music. In the proposed scheme, server distributes each music file in a shuffled form or an encrypted one, then only authorized consumers can play the music after un-shuffling or decrypting it. We show the effectiveness of our proposed scheme by implementing and evaluating the prototype system on WIPI emulator. Experimental results show that our scheme can achieve much better performance than the standard encryption algorithm of OMA DRM.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.171-177
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• 2012

Network mobility support has been taken into consideration for users who have multiple terminals to enjoy the seamless connectivity. This paper proposes a network mobility support scheme in the LISP architecture. During the mobile router attachment, the EID-to-RLOC mapping database is refreshed in the map server. Furthermore, map update is developed to support smooth handoff for the mobile network. An analysis of performance is given by comparing the proposed scheme with NEMO.