• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.05a
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• pp.149-166
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• 2002

국내·외 사회 전 분야의 급속한 전자상거래 발전에 따라 해운·항만 분야에도 인터넷 사업의 진출기회가 확대되고 전략적 활동이 증가하고 있다. 그 중에서도 인터넷을 기반으로 세계가 하나의 시장으로 통합되는 경향을 보이고 있어 기업의 활동 범위가 광역화되고 있으며, 시간과 장소의 통합이 기업간 거래에서 중요시 되고 있다. 지금 세계 각 국은 해상연계 물류, 무역 등 물품의 중개 관련 사이트 및 선박 운송에 따른 각종 해운관련 서비스를 가상 공간에서 제공하는 사이버 해운 시장의 선점 및 구축에 모든 힘을 쏟고 있다. 해상 운송에 따른 각종 수송서비스를 생산, 공급하는 경제활동을 해운 활동이라 한다. 해운 시장의 불확실성, 다변성, 국제성, 개방성을 특성으로 하는 해운 거래는 전자상거래를 통해 효율적으로 처리될 수 있다. 즉, 해운 거래의 비용 감소와 양질의 서비스로 선주, 화주 등 거래 당사자들의 만족도를 높일 수가 있다. 이에 따라 국내에서도 오프라인상의 해운 거래소가 사이버 해운거래소로 옮겨질 예정이다. 가상 공간을 통한 해운 거래의 구체적인 장점은 다음과 같다. 구매업체는 기존 공급업체에 대한 접근 및 새로운 공급업체의 확보가 용이하며, 경쟁 입찰 등을 통해 저렴한 비용으로 물품을 구입할 수 있다. 판매 업체의 경우 채널 확장이 가능하며 판매비를 절감할 수 있다. 또한 e-Marketplace의 입장에서 보면 해운 산업 전체를 위한 새로운 시장을 형성할 수 있으며, 이를 통해 지속적인 수익 창출도 가능하다. 이러한 해운 거래의 B2B e-Marketplace의 출현은 향후 해운 거래의 새로운 패러다임으로 자리 잡을 것이다. 사이버 해운 거래소는 선박 매매와 용선, 화물 거래를 위한 선·화주의 연결, 표준화된 카탈로그 구축, 각종 전자문서 생성, 전자 결제, 온라인 보험 가입, 해운 선용품 판매 및 관련 정보 제공 등 해운 거래를 위한 종합적인 서비스가 제공되어야 한다. 이를 위해, 본문에서는 e-Marketplace의 효율적인 연계 방안에 대해 해운 관련 업종별로 제시하고 있다. 리스트 제공형, 중개형, 협력형, 보완형, 정보 연계형 등이 있는데, 이는 해운 분야에서 사이버 해운 거래가 가지는 문제점들을 보완하고 업종간 협업체제를 이루어 원활한 거래를 유도할 것이다. 그리하여 우리나라가 동북아 지역뿐만 아니라 세계적인 해운 국가 및 물류 ·정보 중심지로 성장할 수 있는 여건을 구축하는데 기여할 것이다.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.313-317
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• 2005

The network ingress filtering is a simple and efficient method for preventing IP source spoofing of fixed nodes. Since mobile hosts cannot communicate with its correspondent nodes if the network ingress filtering is configured in mobile IPv4 network, reverse tunneling was considered as a method for avoiding network ingress filtering. But, unfortunately this method does not solve IP source spoofing of mobile nodes. In this paper, we propose a simple and efficient method for preventing IP source spoofing of mobile nodes assuming that only the mobile hosts connected to foreign agents and the network that foreign agent manages is small.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1847-1854
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• 2005

This paper proposes a approach to configure efficient video-on-demand system by introducing Multicast and Cache Video-on-Demand (MCVoD) system. As a key element or the MCVoD system, interchange agent provides this system with multicasting and switching functions. With the multicasting, the MCVoD system is able to reduce the load on the network as well as VoD servers by transmitting only one video request instead of sending multiple requests on a same video stream. The switching enables clients to receive the lust stream of requested video streams instantly without waiting time and also allows avoiding undesirable duplication of video streams in the system. With various experiment results through simulation about waiting tine and cache hit ratio, we show that the MCVoD system employing the interchange agent provides better performance than current uni-proxy based system.

• Journal of KIISE:Databases
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• v.36 no.1
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• pp.22-29
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• 2009

The World Wide Web has emerged as largest media which provides even a single user to market their products and publish desired information; on the other hand the user can access what kind of information abundantly enough as well. As a result web holds large amount of related information distributed over multiple web pages. The current search engines search for all the entered keywords in a single webpage and rank the resulting set of web pages as an answer to the user query. But this approach fails to retrieve the pair of web pages which contains more relevant information for users search. We introduce a new search paradigm which gives different weights to the query keywords according to their order of appearance. We propose a new arc weight measure that assigns more relevance to the pair of web pages with alternate keywords present so that the pair of web pages which contains related but distributed information can be presented to the user. Our measure proved to be effective on the similarity search in which the experimentation represented the e~arc ranking measure outperforming the conventional ones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.91-97
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• 2022

There is hare and tortoise racing algorithm(HTA) for single-source(SS) singly linked list(SLL) with O(n) time complexity. But the fast method is unknown for general graph with multi-source, multi-destination, and multi-branch(MSMDMB). This paper suggests linear time cycle detection algorithm for given undirected and digraph with MSMDMB. The proposed method reduced the given graph G contained with unnecessary vertices(or nodes) to cycle into reduced graph G' with only necessary vertices(or nodes) to cycle based on the condition of cycle formation. For the reduced graph G', we can be find the cycle set C and cycle length λ using linear search within linear time. As a result of experiment data, the proposed algorithm can be obtained the cycle for whole data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1205-1214
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• 2021

Edge Computing is used as a solution to the cost problem and transmission delay problem caused by network bandwidth consumption that occurs when IoT/CPS devices are integrated into the cloud by performing artificial intelligence (AI) in an environment close to the data source. Since edge computing runs on devices that provide high-performance computation and network connectivity located in the real world, it is necessary to consider application integrity so that it is not exploited by cyber terrorism that can cause human and material damage. In this paper, we propose a technique to protect the integrity of edge computing applications implemented in a script language that is vulnerable to tampering, such as Python, which is used for implementing artificial intelligence, as container images and then digitally signed. The proposed method is based on the integrity protection technology (Docker Contents Trust) provided by the open source container technology. The Docker Client was modified and used to utilize the whitelist for container signature information so that only containers allowed on edge computing devices can be operated.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.1
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• pp.107-116
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• 2009

Quantum-dot Cellular Automata (QCA) is one of the most promising next generation nanoelectronic devices which will inherit the throne of CMOS which is the domineering implementation technology for large scale low power digital systems. In late 1990s, the basic operations of the QCA cell were already demonstrated on a hardware implementation. Also, design tools and simulators were developed. Nevertheless, its design technology is not quite ready for ultra large scale designs. This paper proposes a new approach which enables the QCA designs to inherit the verification methodologies and tools of CMOS designs, as well. First, a set of disciplinary rules strictly restrict the cell arrangement not to deviate from the predefined structures but to guarantee the deterministic digital behaviors is proposed. After the gate and interconnect structures of. the QCA design are identified, the signal integrity requirements including the input path balancing of majority gates, and the prevention of the noise amplification are checked. And then the digital logic is extracted and stored in the OpenAccess common engineering database which provides a connection to a large pool of CMOS design verification tools. Towards validating the proposed approach, we designed a 2-bit adder, a bit-serial adder, and an ALU bit-slice. For each design, the digital logic is extracted, translated into the Verilog net list, and then simulated using a commercial software.

• Journal of Korean Library and Information Science Society
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• v.51 no.2
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• pp.1-21
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• 2020

The purpose of this study is to explore semantic characteristics of IFLA school library guidelines through network analysis. There are two versions, 2002 edition and 2015 revision of the guidelines. This study analyzed the 2002 edition and 2015 revision of the IFLA school library guidelines view point of semantic network, and compared characteristics of two versions. The keywords were to extracted from two texts, semantic network were composed based on co-occurrence relations with keywords. The centrality(degree centrality, closeness centrality, betweenness centrality) was analyzed from the network. In addition, this study conducted topic modeling analysis using LDA function of NetMiner4.0. The result of this study is following these. First, When comparing the centrality, the 'Program, Teaching, Reading, Inquiry, Literacy, Media' keyword was higher in the 2015 revision than in the 2002 edition. Second, 'Inquiry' in degree centrality and 'Achievement' in closeness centrality which were not included in the 2002 edition top-ranked keyword list, have new appeared in 2015 revision. third, As a result of the analysis of topic modeling, compared to the 2002 version, the importance of topics on programs and services, teaching and learning activities of librarian teacher, and media and information literacy is increasing in the 2015 revision.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.847-854
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• 2005

Since the propagation speed of the Internet worms is quite fast, worm detection in early propagation stage is very important for reducing the damage. Virus throttling technique, one of many early worm detection techniques, detects the Internet worm propagation by limiting the connection requests within a certain ratio.[6, 7] The typical throttling technique increases the possibility of false detection by treating destination IP addresses independently in their delay queue managements. In addition, it uses a simple decision strategy that determines a worn intrusion if the delay queue is overflown. This paper proposes a two dimensional delay queue management technique in which the sessions with the same destination IP are linked and thus a IP is not stored more than once. The virus throttling technique with the proposed delay queue management can reduce the possibility of false worm detection, compared with the typical throttling since the proposed technique never counts the number of a IP more than once when it chicks the length of delay queue. Moreover, this paper proposes a worm detection algorithm based on weighted average queue length for reducing worm detection time and the number of worm packets, without increasing the length of delay queue. Through deep experiments, it is verified that the proposed technique taking account of the length of past delay queue as well as current delay queue forecasts the worn propagation earlier than the typical iuぉ throttling techniques do.

• Journal of KIISE:Databases
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• v.35 no.1
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• pp.17-28
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• 2008

Recently, main memory access is a performance bottleneck for many computer applications. Cache memory is introduced in order to reduce memory access latency. However, it is possible for cache memory to reduce memory access latency, when desired data are located on cache. EST tree is proposed to solve this problem by improving T tree. However, when doing a range search, EST tree has to search unnecessary nodes. Therefore, this paper proposes $CST^+$ tree which has the merit of CST tree and is possible to do a range search by linking data nodes with linked lists. By experiments, we show that $CST^+$ is $4{\sim}10$ times as fast as CST and $CSB^+$. In addition, rebuilding an index Is an essential step for the database recovery from system failure. In this paper, we propose a fast tree index rebuilding algorithm called MaxPL. MaxPL has no node-split overhead and employs a parallelism for reading the data records and inserting the keys into the index. We show that MaxPL is $2{\sim}11$ times as fast as sequential insert and batch insert.