• 로봇학회논문지
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• 제14권4호
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• pp.245-250
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• 2019

Milli-scale crawling robots have been widely studied due to their maneuverability in confined spaces. For successful crawling, the crawling robots basically required to fulfill alternating gait with elliptical foot trajectory. The alternating gait with elliptical foot trajectory normally generates both forward and upward motion. The upward motion makes the aerial phase and during the aerial phase, the forward motion enables the crawling robots to proceed. This simultaneous forward and upward motion finally results in fast crawling speed. In this paper, we propose a novel alternating mechanism to make a crab-inspired eight-legged crawling robot. The key design strategy is an alternating mechanism based on double four-bar linkages. Crab-like robots normally employs gear-chain drive to make the opposite phase between neighboring legs. To use the gear-chain drive to this milli-scale robot system, however, is not easy because of heavy weight and mechanism complexity. To solve the issue, the double-four bar linkages has been invented to generate the oaring motion for transmitting the equal motion in the opposite phase. Thanks to the proposed mechanism, the robot crawls just like the real crab with the crawling speed of 0.57 m/s.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.815-819
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• 1996

In this work, regular rotational gaits of the quadruped crawling robot required to change its moving direction without affecting be its orientation and its static stability margin are studied. The regular rotational gaits provide the quadruped crawling robot with omnidirectional characteristics. However, the ideal foothold region for each of legs of the quadruped crawling robot is assumed for simplicity. Nonetheless, it is expected that the results of this paper will provide the insight for both design of legs of the crawling robot with omnidirectional characteristics as well as its operation of the crawling robot system with specified stability margin.

• Journal of Multimedia Information System
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• 제8권1호
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• pp.69-74
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• 2021

This paper accumulates the product structure data such as bond obligation ratio and investment ratio for variable insurance using crawling from the insurance company's API, also accumulates variable insurance income and project expenses for variable insurance using crawling from the API of life insurance association. From these accumulated data, the correlation coefficient between fund product and customer preference is calculated with an investment algorithm, and variable insurance funds by customer investment preference and product structure are recommended according to market conditions. From the simulation results, it is shown that the proposed variable insurance management system properly recommends and manages variable insurance according to customer preferences.

• Interaction and multiscale mechanics
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• 제4권2호
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• pp.165-171
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• 2011

In this study, we proposed a three-dimensional dynamic model under the diffuse interface description for the single crawling cell. From the developed model, we described the clear evolution processes for crawling neutrophil and assessed the reliable quantitative chemotactic property, which confirmed the high possibility of adequate predictions. To establish the system considering of multiple mechanisms such as, diffusion, chemotaxis, and interaction with surface, a diffuse interface model is employed.

• 한국정보통신학회논문지
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• 제26권4호
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• pp.495-502
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• 2022

오늘날 웹상의 본문 수집에 주로 이용되는 웹 크롤러는 연구자가 직접 HTML 문서의 태그와 스타일을 분석한 후 수집 채널마다 다른 수집 로직을 구현해야 하므로 유지 관리 및 확장이 어렵다. 이러한 문제점을 해결하려면 웹 크롤러는 구조가 서로 다른 HTML 문서를 동일한 구조로 정형화하여 본문을 수집할 수 있어야 한다. 따라서 본 논문에서는 태그 경로 및 텍스트 출현 빈도를 기반으로 HTML 문서를 정형화하여 하나의 수집 로직으로 본문을 수집하는 웹크롤링 시스템인 WCTT(Web Crawling system based on Tag path and Text appearance frequency)를 설계 및 구현하였다. WCTT는 모든 수집 채널에서 동일한 로직으로 본문을 수집하므로 유지 관리 및 수집 채널의 확장이 용이하다. 또한, 키워드 네트워크 분석 등을 위해 불용어를 제거하고 명사만 추출하는 전처리 기능도 제공한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.924-927
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• 1996

In this work, we investigate the quasi-static crawling of the four-bar mechanism. Since the crawling of the mechanism is based on sliding of contact points of the mechanism with the ground, interaction forces and friction forces at contact points of the mechanism with the ground should be computed. For this purpuse, we introduce the concept of imaginary joints to find these forces. Therefore, we are able to treat the closed mechanism as a serial one. Also, sliding conditions of the mechanism in quasi-static equilibrium are examined. Lastly, the required torques for the mechanism to crawl with respect to various configurations of the mechanism but with a fixed ground friction are investigated.

• 제어로봇시스템학회논문지
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• 제8권3호
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• pp.226-232
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• 2002

In this work, the quasi-static crawling of the four-bar mechanism is investigated. Since the crawling of the mechanism is based on sliding of contact points of the mechanism with the ground, interaction forces and friction forces at contact points of the mechanism with the ground should be computed. For this purpose, we introduce the concept of imaginary joints to find these forces and treat the closed mechanism as a serial one. Lastly, the required torques for the mechanism to crawl with respect to various configurations of the mechanism on a flat ground with uniform friction coefficient, based on sliding conditions of the mechanism in quasi-static equilibrium, are investigated.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2017년도 제56차 하계학술대회논문집 25권2호
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• pp.241-244
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• 2017

인터넷을 이용하는 사용자들은 원하는 정보를 획득하고 타인들과 소통하기 위한 방법으로 소셜 네트워크 서비스를 이용한다. SNS는 사용자별로 차별화된 기능을 제공함으로써 수요자를 증가시키지만 이를 활용하는 사용자들은 무분별한 콘텐츠를 접함으로써 사용자 인터페이스에 대한 불편함은 더해가고 있다. 본 연구는 SNS를 이용하는 사용자들의 사용자 편이성을 증가하고 콘텐츠 접근성을 강화하는 방안으로 원하는 관심사만 자동으로 수집하여 열람하도록 JAVA WEB CRAWLING을 활용하여 시스템을 개발하였다.

• 한국컴퓨터정보학회논문지
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• 제24권4호
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• pp.123-128
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• 2019

In modern society, there are WEB sites that provides information in various fields by many advances in IT technology. As the number of users accessing the Web increases, one server becomes unavailable, and multiple servers are deployed to provide the service. In addition, systems that control servers are required to manage multiple servers. However, server control systems in the existing market are mostly those that notify managers through SMS and apps when a server's down or a controlled port is closed. However, in case of servers that generate a lot of traffic, the Web server and the WAS are operated and managed each independently. The WEB and WAS provide service by connecting to each other. However, the connection between WEB and WAS may be disconnected due to various environmental factors. In this case, the existing control system can not determine whether the service is working properly. Even in the case of WEB and WAS of a server that is operated independently, there is a phenomenon that the existing control system does not know the problem even when the normal service is not provided due to environmental factors such as disconnection to DB. In this paper, we implemented a system to check the normal state of Web service using Web crawling to solve this problem.

• 한국멀티미디어학회논문지
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• 제22권3호
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• pp.374-385
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• 2019

A Web Crawler is a program, which is commonly used by search engines to find the new brainchild on the internet. The use of crawlers has made the web easier for users. In this paper, we have used unstructured data by structuralization to collect data from the web pages. Our system is able to choose the word near our keyword in more than one document using unstructured way. Neighbor data were collected on the keyword through word2vec. The system goal is filtered at the data acquisition level and for a large taxonomy. The main problem in text taxonomy is how to improve the classification accuracy. In order to improve the accuracy, we propose a new weighting method of TF-IDF. In this paper, we modified TF-algorithm to calculate the accuracy of unstructured data. Finally, our system proposes a competent web pages search crawling algorithm, which is derived from TF-IDF and RL Web search algorithm to enhance the searching efficiency of the relevant information. In this paper, an attempt has been made to research and examine the work nature of crawlers and crawling algorithms in search engines for efficient information retrieval.