• Annual Conference of KIPS
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• 2007.11a
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• pp.211-214
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• 2007

최근 멀티미디어 데이터, 특히 UCC를 중심으로 동영상 데이터가 급증하고 있다. 그러나 현재 대부분의 검색 시스템은 키워드 기반의 동영상 데이터 검색만을 지원하고 있으며, 따라서 사용자가 원하는 동영상 데이터를 효율적으로 검색하지 못하는 실정이다. 동영상 데이터에 대한 효율적인 검색을 지원하기 위해서는, 동영상의 내용(이미지, 색, 모양 등)을 고차원의 특징 벡터 데이터로 표현하여 유사한 동영상을 검색하는 내용-기반 검색이 요구된다. 본 논문에서는 내용-기반 검색을 위해 제안된 기존의 고차원 벡터 데이터 색인 구조를 실험을 통하여 성능을 비교하며, 이를 통해 동영상 내용-기반 검색에 가장 효율적인 색인 기법을 제시한다. 아울러 보다 효율적인 내용-기반 검색을 위한, 근사 k-NN 질의 탐색 기법의 유용성을 검증한다.

• Annual Conference of KIPS
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• 2007.05a
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• pp.1439-1442
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• 2007

임베디드 시스템이 빠른 속도로 활성화되는 가운데 기존의 웹서버가 임베디드 시스템에 적합하게 변형되거나, 또는 임베디드 시스템 전용 미니 웹서버가 개발 및 운영되고 있는 실정이다. 미니웹서버는 기존 웹서버들과는 여러 가지 면으로 다른 모습과 특징을 갖게 된다. Tiny Web 또는 Small Web 이라고 명명되기도 하며 각 미니 웹서버 마다 기능도 다양하다. 임베디드 미니 웹서버의 기능 및 성능을 기존 웹서버과 비교 분석한다.

• International journal of advanced smart convergence
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• v.13 no.3
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• pp.31-40
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• 2024

The proliferation of video streaming services has led to a need for flexible networking protocols. As a result, the Dynamic Adaptive Streaming over HTTP (MPEG-DASH) protocol has emerged as a dominant streaming protocol due to its ability to dynamically adjust playback bitrates according to the end-user's network conditions. In this paper, we propose a novel I/O scheduling scheme tailored for the storage of MPEG-DASH-enabled video servers. Using the renowned rate-reservation (RR) algorithm and bulk-SCAN mechanism, our proposed scheme improves storage bandwidth utilization while ensuring seamless playback of streams with varying bitrates. In addition, we provide a mechanism for reclaiming the idle I/O time typically incurred while retrieving video segments from storage. Consequently, our scheme offers practical solutions for reducing the storage costs of MPEG-DASH video servers. With a simple cost model, we evaluate the performance enhancements achieved by our proposed I/O scheduling scheme.

• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.91-100
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• 2020

This paper presents an evaluation framework for prototyping multimedia streaming services including audio and video in a distributed and/or decentralized storage that can evaluate service quality and performance under various network conditions. The evaluation framework focuses on important indicators which measure and improve service quality by applying decentralized storage to multimedia streaming services that can mimic the scalability of the existing server-client software architecture and the issue of a single point of failure. The integrated framework not only measures performance indicators for evaluating the quality and performance of multimedia streaming on open source based multimedia content streaming services, but also adjusts network quality using network virtualization technology for comprehensive evaluations. The experimental results show that the integrated framework has low overhead in building and operating a decentralized storage with multimedia streaming services on a single host computer which validates the scalability of the developed framework.

• The KIPS Transactions:PartC
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• v.11C no.5
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• pp.683-688
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• 2004

NAT is a very useful IP address translation technique that allows two connected networks using different and incompatible IP address schemes. But it is impractical to use NAT for an application which uses the encrypted IP packet, embedding IP addresses inside of data payloads, to guarantee End-to-End Security such as IPSec. In addition to rewriting the source/destination IP addresses in the packet, NAT must modify IP checksum every time, which could lead to considerable performance decrease of the overall system in the process of the address translation. RSIP is an alternative to solve these disadvantages of NAT and the address shortage problems. Both NAT and RSIP divide networks into inside and outside addressing realms. NAT translates addresses between internal network and external network, but RSIP uses a borrowed external address for outside communications. RSIP server assigns a routable public address to a RSIP client temporarily to communicate with public net-work outside of the private network. In this paper, RSIP gateway for intranet environment is designed and its performance is evaluated. From the results of performance evaluation, we knew that RSIP is operated less sensitive to the data traffic. Also, the experiment shows that RSIP performs better than NAT when the transmission data grows larger.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2370-2387
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• 2000

This paper proposes a new design strategy that can overcome limitations of two existing approaches, focusing on performance and scalability issues among various architectural issues which must be considered in designing workflow systems. In the proposed approach, we suggest to introduce 'delegation model' which corresponds to the high-level strategy utilizing the fundamental characteristics of mobile agents, after establishing a mobile agent-based workflow system architecture focused on performance and scalability. We point out three major issues that should be considered in this approach and propose a 3-tier mobile agent-based workflow system architecture that effectively reflects these considerations. Also, we show that the new approach can provide better performance and scalability than existing ones - approaches based on the client-server paradigm and other approaches based on mobile agent paradigm represented by DartFlow system - by evaluating performance of the proposed architecture through the GSPN simulation.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.45-53
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• 2014

UI-Mashup is widely used as a service method to add value, which is composed of distributed various contents on the internet and has turned out to be one of the latest trends in web application program development. Previous UI-Mashup-related studies have focused primarily on the dynamic service composition and have not been able to adapt to a rapidly changing Web Standard, thusthe end users conclude that UI-Mashups are slow, incompatible and poor security services. In this study, We propose an architecture for the performance improvements of UI-Mashup.In order to provide fast services and security enhancements, the proposed architecture collects UI fragments on the server in parallel, and sends layouts and contents of Mashups UI to the client through a special delivery channel supporting fast reaction and response time. In this study, the implementation and performance tests were proceeded to verify the proposed architecture experimentally. As a result of the performance testing, the proposed architecture has two to three times faster response time and more than four times throughput compared to the previous UI-Mashup technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.111-117
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• 2017

The National Competency Standards (NCS) was designed to implement a competence-based society and solve the problem of inconsistency between the industrial field and education, training, and certification system. This study designed and developed the Korean NCS core vocational competence system, in accordance with the NCS, as an infrastructure to solve fundamental problems such as re-education and the social costs that are incurred in the workplace. Further, this study designed and developed standard indicators to evaluate the technical performance of the system for the global advancement of the Korean NCS core vocational competence system. The NCS core vocational competence system has been developed as an appropriate response type for multiple devices such as computers, tablet PCs, and cellular phones. For the global advancement of the Korean NCS core vocational competence system, this study designed and developed 10 performance evaluation indicators in accordance with 10 global standards, such as linkage-target operating system, interface protocol, packet format, encryption, class component, simultaneous access number, supervisor-to-testtaker response speed, server-to-admin response speed, auto-recovery speed for test answers, and real-time answer transmission speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.166-174
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• 2010

SSDs are one of the best media to support portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major database storage components for desktop and server computers. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of flash memory operations, as compared to RAM memory. In order to achieve this goal, we propose a new index management scheme based on a compressed hot-cold clustering called CHC-Tree. CHC-Tree-based index management improves index operation performance by dividing index nodes into hot or cold segments and compressing pointers and keys in the index nodes and clustering the hot or cold segments. The offset compression techniques using unused free area in cold index node lead to reduce the number of slow erase operations in index node insert/delete processes. Simulation results show that our scheme significantly reduces the write and erase operation overheads, improving the index search performance of B-Tree by up to 26 percent, and the index update performance by up to 23 percent.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.99-107
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• 2010

SNMP(Simple Network Management Protocol) is most commonly used as a standard protocol for effective network management by supporting the increasing size of the network and the variety of network elements such as router, switch, server and so on. However, SNMP has performance drawbacks of network overhead, processing latency, and the inefficiency in data retrieval. In this paper, we propose two schemes to improve the performance of SNMP; 1) the first scheme to reduce the amount of redundant OID information within a SNMP-GetBulk response message, 2) the second scheme of newly proposed SNMP-GetUpdate message combined with the cache in MNS. Through the analysis with real experiments, we show that our first scheme reduces the network overhead and the second scheme improves the processing latency and the retrieval of SNMP MB tables. And, therefore the scalability of network management can be improved.