• Journal of Computing Science and Engineering
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• v.2 no.4
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• pp.321-338
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• 2008

This paper presents a Modified Multiple Depth First Search algorithm for the exploration of the indoor environments occupied with obstacles in random distribution. The proposed algorithm was designed and implemented to employ one or a team of Khepera II mini robots for the exploration process. In case of multi-robots, the BlueCore2 External Bluetooth module was used to establish wireless networks with one master robot and one up to three slaves. Messages are sent and received via the module's Universal Asynchronous Receiver/Transmitter (UART) interface. Real exploration experiments were performed using locally developed teleworkbench with various autonomy features. In addition, computer simulation tool was also developed to simulate the exploration experiments with one master robot and one up to ten slaves. Computer simulations were in good agreement with the real experiments for the considered cases of one to one up to three networks. Results of the MMDFS for single robot exhibited 46% reduction in the needed number of steps for exploring environments with obstacles in comparison with other algorithms, namely the Ants algorithm and the original MDFS algorithm. This reduction reaches 71% whenever exploring open areas. Finally, results performed using multi-robots exhibited more reduction in the needed number of exploration steps.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.487-490
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• 2005

이동 에이전트란 어떠한 동작을 수행하는 명령과 자신의 상태 정보를 포함하는 자율적인 소프트웨어 객체이다. 이동 에이전트는 자율적으로 이동할 수 있으며 복제와 증식이 가능하고 사용자의 업무를 대신해서 수행할 수 있다는 장점으로 인해 전자상거래에서 사용자를 대신하여 상품 검색 및 구매에 사용될 수 있다. 이 때 다수의 이동 에이전트가 하나의 그룹이 되어 서로 메시지를 주고받으며 사용자의 요구사항을 수행한다. 이동 에이전트간 전달되는 메시지는 상품의 정보뿐 아니라 사용자 또는 에이전트의 비밀정보가 될 수 있다. 악의를 가진 외부 개체로부터 그룹 멤버쉽이나 메시지가 변경된다면 이동 에이전트 그룹은 사용자가 의도하지 않는 동작을 수행할 수 있다. 본 논문에서는 이러한 공격을 방어하기 위해 그룹 멤버간 암호화 통신을 할 수 있는 그룹 세션키 생성 기법을 제안한다. 기존 기법과는 달리 본 논문에서는 중앙 키 분배 서버 없이 그룹에 참가하는 이동 에이전트 각자 그룹 세션키를 생성한다. 또한 키 갱신을 주기적으로 수행함으로써 외부 개체로부터 그룹 세션키의 습득을 어렵게 한다.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.129-134
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• 2003

This paper describes an application level composition mechanism called Generic Modeling Environment(GME) for web caching on an Application Level Active Network(ALAN). Web caching on an ALAN requires the application level composition mechanism and a service composition to support adaptability for self-organization. ALAN was developed to solve the problems of the network level Active Network(AN) ALAN has the features of both AN as well as mobile agents. The efficient composition mechanism for the existing AN Projects has been supported primarily for the network level AN. Conversely, ALAN lacks support for the application level AN The existing web caching technology is inter-connected in a manually configured hierarchical tree. Since a self-organization system is intended to be adaptive, web caching for self-organization does not involve a manual configuration or any low-level tuning of the individual nodes of the entire system but requires service composition to support adapting intelligence and fault-tolerance to enable self-organization.

• International Journal of Contents
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• v.5 no.1
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• pp.51-55
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• 2009

In this paper, we present a structure of personalized e-Learning system to study for a test formalized by uniform multiple-choice using on/off line mixed estimations as is the case of Driver :s License Test in Korea. Using the system a candidate can study toward the license through the Internet (and/or mobile instruments) within the personalized concept based on IRT(item response theory). The system accurately estimates user's ability parameter and dynamically offers optimal evaluation problems and learning contents according to the estimated ability so that the user can take possession of the license in shorter time. In order to establish the personalized e-Learning concepts, we build up 3 databases and 2 agents in this system. Content DB maintains learning contents for studying toward the license as the shape of objects separated by concept-unit. Item-bank DB manages items with their parameters such as difficulties, discriminations, and guessing factors, which are firmly related to the learning contents in Content DB through the concept of object parameters. User profile DB maintains users' status information, item responses, and ability parameters. With these DB formations, Interface agent processes user ID, password, status information, and various queries generated by learners. In addition, it hooks up user's item response with Selection & Feedback agent. On the other hand, Selection & Feedback agent offers problems and content objects according to the corresponding user's ability parameter, and re-estimates the ability parameter to activate dynamic personalized learning situation and so forth.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1577-1580
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• 2000

컴퓨터통신의 중요성이 부각되고 있는 가운데 이동 컴퓨팅 환경에서 데이터를 전송함에 있어서 손실 없이 할 수 있도록 해야한다. 외부 에이전트가 이동 노드로 전송하는 데이터를 이동 노드의 이동성에 의해 이동 노드로 전달되지 못하는 경우가 발생한다면 실시간 데이터는 연속적으로 데이터를 받지 못하여 끊김 현상이 발생하게 된다. 이동 노드는 이동한 새로운 외부 에이전트에 등록을 하고 인터넷 호스트로부터 데이터를 받을 수 있는 환경이 구축되기 전까지 데이터통신이 불가능하다. 그러므로 기존의 기법으로는 실시간 데이터 통신을 할 경우 이동 노드의 이동성을 지원할 수는 있지만 효과적이지는 않다. 이에 대한 해결책으로 외부 에이전트가 유선망과 무선망을 연계하고 이동 노드가 이동하며 실시간 데이터 통신을 하는 경우, 외부 에이전트는 홈에이전트와 인터넷 호스트에게 이동하게 될 외부에이전트의 정보를 보내서 홈에이전트는 이동노드에 대한 정보만을 갱신하여 효과적으로 성능을 개선할 수 있고, 인터넷 호스트는 바로 이동할 에이전트에게 데이터를 보내어 빠르고 연속적인 데이터를 보낼 수 있도록 하는 기법을 제안한다.

• KSBB Journal
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• v.30 no.4
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• pp.191-196
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• 2015

Blueberry juice possesses rich-procyanidins and - anthocyanidin, comprised a group of with numerous health benefits such as protection against coronary heart disease, detoxification, and obesity. Blueberry (Vaccinium virgatum) juice extracts were analyzed and separated by an HPLC method for the purpose of the separation and quantification in polyphenolic groups. In specific HPLC conditions, a binary mobile phase consisting of formic acid: water (10:90, v/v, solvent A) and formic acid: water: acetonitrile (10:60:30, v/v/v, solvent B) was utilized and it is detected at 546 nm wavelength. The phenolic contents of the extracts are determined using Folin-Ciocalteu phenol reagent. In order to test anti-inflammation activity assay, after producing nitric oxide (NO) in lipopolysaccharide activated RAW 264.7 cells, at concentration of $20-500{\mu}g/mL$ it reduced to NO production at a dose-dependent manner. Importantly, cytotoxicity assay with up to $500{\mu}g/mL$ of the extract from blueberry juice showed ~100% cell viability for RAW264.7 cell line. Therefore, Korean blueberry juice might have potential as anti-oxidant and antiinflammation agents.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.71-82
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• 2004

Recently, network model inspired by social insect behavior attracts the public attention. The AntNet is an adaptive and distributed routing algorithm using mobile agents, called ants, that mimic the activities of social insect. In this paper. we present a new hardware architecture to realize an AntNet-based routing in practical system on a chip application. The modified AntNet algorithm for hardware implementation is compared with the original algorithm on the various traffic patterns and topologies. Implementation results show that the proposed architecture is suitable and efficient to realize adaptive routing based on the AntNet.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.272-276
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• 2000

컴퓨터 및 인터넷의 대중화가 급속도로 이루어지면서 전자상거래의 한 부분인 전자경매에 대한 관심과 개발이 상당부분 이루어지고 있다. 웹을 통한 전자경매의 발달로 직접 경매장에 가지 않고서도 적은 비용으로 다양한 상품들을 구매 및 판매할 수 있으므로 소비자와 공급자 모두에게 편의성과 이익을 제공해 주고 있다. 한편 에이전트에 대한 관심이 높아지면서 전자경매 시스템에 이를 적용하여 경매참여자의 편의성과 효율성을 증대시키려는 노력들도 활발히 이루어지고 있다. 대표적인 에이전트 기반 전자경매 시스템으로는 미국 워싱턴대학의 eMediator, 미시건대학의 AuctionBot, 스웨덴의 FishMarket 등이 있다. 이들 시스템들은 지원하는 경매유형, 입찰가격정책, 상품유형, 경매대상, 에이전트의 역할 및 기능등에서 상당한 차이를 보이고 있다. 본 논문에서 제안하는 전자경매시스템은 특히 경매참여자인 사용자의 편의성과 경매관리 및 운영의 안정성을 목표로 하고 있다. 에이전트 기반의 전자경매 시스템을 개발함으로써 기본적으로 사용자 인터페이스를 통한 경매참여와 사용자가 직접 에이전트를 생성하여 이동시킴으로써 경매에 참여하는 방법을 제공한다. 두 방법 모두 참여자가 직접 경매에 참여하는 것이 아니고 에이전트를 통해 언제 어디서나 경매에 참여하여 원하는 가격대로 상품을 구매하거나 팔 수 있도록 시스템을 개발하는데 목적이 있다.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.119-125
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• 2006

Distributed Systems can be defined as set of computing resources connected by computer network. One of the most significant techniques in optimization problem domains is parallel genetic algorithms, which are based on distributed systems. Since the status of dynamic network environments such as Internet and mobile computing. can be changed continually, it must not be efficient on the dynamic environments to solve an optimization problem using previous parallel genetic algorithms themselves. In this paper, we propose the effective technique, in which the parallel genetic algorithm can be used efficiently on the dynamic network environments.

• Toxicological Research
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• v.35 no.2
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• pp.161-165
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• 2019

Cysteamine has been used in cosmetics as an antioxidant, a hair straightening agent, and a hair waving agent. However, recent studies indicate that cysteamine can act as an allergen to hairdressers. The objective of this study was to develop and validate a simple and effective reversed-phase high-performance liquid chromatography (RP-HPLC) method for the measurement of cysteamine and its dimer, cystamine. Sodium 1-heptanesulfonate (NaHpSO) was used as an ion-pairing agent to improve chromatographic performance. Separation was performed on a Gemini C18 column ($250mm{\times}4.6mm$, $5{\mu}m$ particle size) using a mobile phase composed of 85:15 (v/v) 4 mM NaHpSO in 0.1% phosphoric acid:acetonitrile. UV absorbance was monitored at 215 nm. The RP-HPLC method developed in this study was validated for specificity, linearity, limit of detection, limit of quantitation, precision, accuracy, and recovery. Cysteamine and cystamine were chromatographically resolved from other reducing agents such as thioglycolic acid and cysteine. Extraction using water and chloroform resulted in the recovery for cysteamine and cystamine ranging from 100.2-102.7% and 90.6-98.7%, respectively. This validated RP-HPLC method would be useful for quality control and monitoring of cysteamine and cystamine in cosmetics.