• Journal of information and communication convergence engineering
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• v.10 no.4
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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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• v.4 no.2
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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.

• Journal of Information Technology Services
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• v.14 no.4
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.71-80
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• 2008

We have studied to protect location and identity privacy of mobile users in mobile communication environments. In this paper, we propose and analyze new mobile originated protocols as a part of our new integrated system for high level privacy protection service which is not provided in the traditional GSM[1] system of europe. Also our protocols support a roaming service into the remote domain as welt as the home domain.

• International journal of advanced smart convergence
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• v.4 no.1
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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.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.2
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• pp.14-20
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• 1999

In this paper, we discuss about implementation of a wireless communication system for a distributed autonomous robotic system. In order to achieve cooperative behavior among mobile robots, it is required to perform communication. Based on this requirements, we examined to the application in a wireless communication system used by mobile robots. This paper describes a conceptual and experimental framework which provides a distributed control architecture for the study of interactions between multiple mobile robots.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.2
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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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• v.1 no.1
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.586-592
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• 2006

Mobile Services are that function of information system are served in mobile environment. So, Success model for the mobile services might be derived through mixing success model of information system with mobile attributes. There are many kinds of mobile services. Specially, commerce, communication entertainment and information services are representative types in mobile services. In this paper, we do not only derive important factors that influence success of mobile services, but also analyze how the factors influence the success of mobile services. We also analyze whether measures of the factors might differ significantly among the types of mobile services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.786-796
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• 2009

Currently, web syndication is usually utilized in desktop environments, but not considering mobile environments. In this paper, we focus on the extension of the desktop based web syndication to the mobile internet. Simply adapting the desktop based web syndication to mobile devices can cause high wireless internet communication cost. We propose PMS(Proxy-based Mobile Syndication) model which achieves low cost mobile syndication. In the PMS model, MWProxy is defined as a proxy server between mobile devices and web sites. It can reduce the communication cost by peeking up modified items from the web sites and reducing the channel size. In this paper, we designed and implemented the PMS system in a mobile phone and evaluated the performance of the PMS system by conducting real experiments using mobile emulators.