• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.372-377
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• 2012

In this paper, we propose an implementation of a real-time operating system for the two-wheel mobile robot. With this implementation, we have the ability to control the complex embedded systems of the two-wheel mobile robot. The advantage of the real-time operating system is increasing the reliability and stability of the two-wheel mobile robot when they work in critical environments such as military and industrial applications. The real-time operating system which was ported to this implementation is open systems and the corresponding interfaces for automotive electronics (OSEK/VDX). It is known as the set of specifications on automotive operating systems, published by a consortium founded by the automotive industry. The mechanical design and kinematics of the two-wheel mobile robot are described in this paper. The contributions of this paper suggest a method for adapting and porting OSEK/VDX real-time operating system to the two-wheel mobile robot with the differential drive method, and we are also able to apply the real-time operating system to any complex embedded system easily.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.29-33
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• 2015

In this paper, we propose the method to improve the performance of the antenna system that contains three bands, such as Lte3G, WLAN and Lte4G. This antenna has an advantage that can cover the three different frequency bands 2.1GHz, 2.4GHz and 2.6GHz through one antenna design. The design and simulations are done using CST Microwave Studio 2014 program. The antenna is designed by using the FR-4 (lossy) substrate with the dielectric constant of er=4.3 and dielectric loss tangent 0.025. The substrate dimensions are the following; Thickness[h] is 1.6mm, Length is 90mm, and Width is 40mm. The ground is designed by using the PEC material with h=0.035mm. The patch is designed by using the copper with h=0.035mm. In the near future, we will fabricate the antenna, which we have designed, and then apply this antenna to the mobile communication system. And we will test this mobile communication system for the diverse environments.

• 한국IT서비스학회지
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• 제14권4호
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• pp.257-267
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• 2015

We propose a vehicle-mounted, location-aware mobile digital signage system that can be used for public transportation through mobile communication. This paper proposes the installations of the LED display panels at the backside of the bus., which display traffic information to cars behind the bus. Information to be displayed would include, but is not limited to, road information, public commercials and private commercials. We propose the system architecture and further implement the prototype of mobile digital signage system for demonstration. The system is based on the Client-Server system. Each bus has a client terminal which detects the current location by a GPS receiver and sends its location information to the server using mobile communication function. The terminal device receives advertisements and traffic information from the server and displays it to the large LCD or LED panel installed at the inside and outside of the bus. We use the Android smartphone as a client system, which inherently equipped with GPS and mobile communication function. GPS detects the location of bus and reports its geo-location data to the traffic information center server via a wireless communication network. On the server side, we developed a specially designed control server, where it communicates with the other traffic information center and updates and manages the databases contents being displayed by each position. The server contains location dependent variable information and returns selected information back to the vehicle in real time. Spatial database is used to process location based data. Server system periodically receives the real time traffic information from the road information center database. And it process the information by bus location and bus line number. In this paper, we propose a mobile digital signage service and explain the system implementation of this service.

• 한국정보통신학회논문지
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• 제12권1호
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• pp.71-80
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• 2008

본 논문은 차세대 이동통신 환경에서 이동 사용자에 대한 위치와 신분 프라이버시를 만족하기 위해 개발 중인 새로운 통합시스템의 일부로, 종전 유럽의 GSM(1) 시스템에서 제공되지 못한 고수준의 프라이버시를 만족하는 새로운 이동발호프로토콜을 제안하고 분석 한 것이다. 아울러 제안하는 프로토콜은 이동 사용자가 홈 도메인에서만 머무르는 것이 아니라 원격지 도메인으로 이동하는 경우를 포함한다.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.71-87
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• 2015

Mobile users want to be provided with undisrupted network services when they navigate on the Next-Generation (NG) wireless networks. For that, interlocking with a heterogeneous network is important, but there have been few studies on the method for guaranteeing global mobility. Thus, this paper proposes the Proxy-LMA technique, the mobile IP-based global inter-networking system, to enhance global mobility and interoperability within the Next-Generation (NG) network environment. The purpose of the proposed Proxy-LMA system is to expand the boundary of the mobility with regards to the existing mobility management protocol (PMIPv6 and MIPv6) in order to guarantee global mobility and interoperability within the heterogeneous network environment. The results of the performance evaluation showed that the proposed Proxy-LMA system was more efficient than other methods from the standpoint of signaling cost and delay in the heterogeneous network environment.

• 전자공학회논문지T
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• 제36T권2호
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• pp.14-20
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• 1999

본 논문에서는 자율분산로봇의 무선 통신시스템에 관하여 연구하였다. 이동로봇 사이의 협조 동작을 위하여 통신의 구현이 필요하다. 따라서, 우리는 이동로봇에 무선통신시스템을 적용하여 실험하였다. 그리고, 여러 이동로봇 사이의 상호작용을 연구하기 위하여 분산된 제어구조의 개념과 실험적 구조를 설명한다.

• 대한산업공학회지
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• 제32권2호
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• pp.120-125
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• 2006

Since Korean government has implemented the "Number Portability System" in the domestic mobile communications market, mobile communication companies have been striving to hold onto existing customers and at the same time to attract new customers. This paper presents a competing risk model that considers the characteristics of a customer in order to predict the customer's life under the "Number Portability System." Three competing risks considered are pricing policy, quality of communication, and usefulness of service. It was observed that the customers who pay more are less sensitive on pricing policy younger people are less sensitive than older people to the quality of communication and women are more sensitive than men to the degree of usefulness of service. We expect that the result of this study can be used as a guideline for effective management of mobile phone customers under the Number Portability System.

• IEIE Transactions on Smart Processing and Computing
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• 제1권1호
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• pp.65-71
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• 2012

Mobile RFID is a new application that uses a mobile phone as an RFID reader with wireless technology and provides a new valuable service to users by integrating RFID and ubiquitous sensor network infrastructures with mobile communication and wireless Internet. Whereas the mobile RFID system has many advantages, privacy violation problems on the reader side are very concerning to individuals and researchers. Unlike in regular RFID environments, where the communication channel between the server and reader is assumed to be secure, the communication channel between the backend server and the RFID reader in the mobile RFID system is not assumed to be safe. Therefore it has become necessary to devise a new communication protocol that secures the privacy of mobile RFID-enabled devices. Recently, Lo et al. proposed a mutual key agreement protocol that secures the authenticity and privacy of engaged mobile RFID readers by constructing a secure session key between the reader and server. However, this paper shows that this protocol does not meet all of the necessary security requirements. Therefore we developed an enhanced mutual key agreement protocol for mobile RFID-enabled devices that alleviates these concerns. We further show that our protocol can enhance data security and provide privacy protection for the reader in an unsecured mobile RFID environment, even in the presence of an active adversary.

• 한국정보통신학회논문지
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• 제10권3호
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• pp.586-592
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• 2006

모바일서비스는 정보시스템의 기능을 모바일 환경에서 제공하는 것이라고 할 수 있다. 따라서, 모바일서비스의 성공모형은 정보시스템의 성공모형에 모바일의 특성을 적용하여 도출될 수 있다. 다양한 모바일서비스들이 존재하고 있으며 특히, Commerce, Communication, Entertainmant, Information등은 많이 이용되고 있는 모바일서비스 유형들이다. 본 논문에서는 모바일서비스의 성공에 영향을 미치는 주요 요인들을 도출하고 서비스 유형별로 각 요인들이 어떠한 차이가 있는지를 분석해 본다.

• 한국통신학회논문지
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• 제34권8B호
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• pp.786-796
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• 2009

현재 웹 신디케이션 기술은 주로 데스크탑 환경에서 구현 활용되고 있기 때문에 이동성에 대한 고려가 되어 있지 않다. 본 논문에서는 데스크탑 기반의 웹 신디케이션 기술을 모바일 인터넷으로 확장하는데 초점을 맞추었다. 모바일 단말기에서 데스크탑 기반의 웹 신디케이션을 단순히 적용하게 되면 정기 구독으로 인해 높은 무선통신 비용을 초래할 수 있다. 본 논문은 낮은 통신 비용으로 모바일 신디케이션을 구현할 수 있는 PMS(Proxy-based Mobile Syndication) 모델을 제안한다. PMS 모델은 모바일 단말기와 웹 사이트 사이에 프록시 서버인 MWProxy를 정의한다. 프록시 서버는 웹 사이트에서 수신한 채널에서 변경된 아이템을 선택하여 간소화한 채널로 재구성함으로써 통신 비용을 줄일 수 있는 장점이 있다. 본 논문에서는 PMS 모델을 실제 휴대폰 상에서 설계 구현하고 에뮬레이터를 이용하여 성능을 평가하였다.