• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.838-843
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• 2002

Recently, PDA and cellular phone with color LCD have been widely used in various fields by high efficiency and micro miniaturization technology. According to maturity of these mobile environments, user request about mobile application field is increased. Mobile applications provide various information which is concerned with user's position through cable and wireless transmission. This paper discusses the issues related to the mobile framework for integrated 4S data. The integrated 4S data mean spatial data fusion on GIS, SIIS, ITS, and GNSS. The mobile framework provides not only spatial data but also location services such as reverse geocoding, directory service, etc. It consists of client subsystem, service provider, and data provider.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.361-364
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• 2002

EJB(Enterprise JavaBeans)는 서버 상의 Java 컴포넌트와 그 컴포넌트를 위한 동작 환경을 제공하는 전체 프레임웍(Framework)이다. EJB 에서 동작하는 컴포넌트를 엔터프라이즈 빈(Enterprise Bean)이라고 하고, 그 컴포넌트가 동작하기 위한 환경을 컨테이너(Container)라 한다 EJB 에서는 기존에 개발자가 직접 컴포넌트로 제공해 주어야 하는 트랜잭션, 영속성, 보안문제, 데이터베이스 연결 풀링, 쓰레딩 관리 같은 기능을 컨테이너에서 처리해 줌으로 일반 개발자는 복잡한 하부 로직에 신경쓰지 않으면서 더 쉽고 빠르게 동일한 기능을 구현할 수 있게 된다. 본 논문에서는 이러한 EJB 컨테이너를 설계함에 있어서 하나의 중요한 요소인 트랜잭션 관리에 관한 설계를 논한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.401-404
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• 2002

EJB 는 분산 트랜잭션 기반의 엔터프라이즈 어플리케이션을 위한 컴포넌트 컴퓨팅을 위한 아키텍처이다. EJB 는 J2EE 플랫폼을 위한 서버 측 컴포넌트 아키텍처이며, J2EE 플랫폼의 재사용 가능하고 J2EE 기술 중에서 다중 플랫폼 또는 다중 서버에 이식 가능한 비즈니스 로직을 표현하는 코어 기술이다. EJB 기술을 사용하게 되면 응용 로직 개발자들은 시스템 영역의 서비스들 즉, 트랜잭션, 보안, 생명주기, 쓰레딩, 영속성_등의 기능을 직접 구현하지 않고 손쉽게 응용 로직을 개발할 수 있다. 본 논문에서는 J2EE 의 핵심 서버인 EJB 서버 시스템의 설계 사상과 네이밍 및 디렉토리 관리 모듈에 대한 구체적인 설계 방안을 제시한다.

• Electronics and Telecommunications Trends
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• v.24 no.3
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• pp.69-77
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• 2009

세계 주요 국가들은 HDTV 이후의 방송 서비스를 위한 준비 작업들을 진행하고 있으며, 그 중 하나가 UHDTV이다. UHDTV는 가정에서 70 mm 영화 수준의 화질(화면 해상도 $7680{\times}4320$, HD 화면 16배 크기에 해당)을 갖는 초고선명 비디오 서비스 제공을 목표로 한다. 본 고에서는 초고선명 비디오 서비스의 핵심 기술 중 하나인 초고선명 비디오 부호화 기술에 대한 기술 동향을 소개한다.

• ETRI Journal
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• v.32 no.2
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• pp.255-264
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• 2010

Interference scenarios and methodologies between a terrestrial mobile service (MS) system and mobile-satellite service (MSS) system in a co-channel environment are established. Taking into account a practical deployment situation for both systems, we perform computational simulation of interference in terms of carrier-to-interference ratio (C/I) and interference-to-noise ratio (I/N) to evaluate the cofrequency interference from an MS system into an MSS system, and from an MSS system into an MS system, respectively. The methodology and results can be used as a guide when planning the deployment of MSS and MS systems with no unacceptable interference impact between them.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1587-1605
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• 2015

Mobile cloud computing (MCC) combines mobile Internet and cloud computing to improve the performance of applications. In MCC, the data processing and storage for mobile devices (MDs) is provided on the remote cloud. However, MCC faces the problem of energy efficiency caused by randomly varying channels. In this paper, by introducing the Lyapunov optimization method, we propose a combined service subscription and delivery (CSSD) algorithm that can guide the users to subscribe to services reasonably. This algorithm can also determine whether to deliver the data and to whom data is sent in the current time unit based on the queue backlog and the channel state. Numerical results validate the correctness and effectiveness of our proposed CSSD algorithm.

• ETRI Journal
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• v.38 no.3
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• pp.551-559
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• 2016

In this paper, we propose a hybrid sensor calibration scheme for mobile crowdsensing applications. As the number of newly produced mobile devices containing embedded sensors continues to rise, the potential to use mobile devices as a sensor data source increases. However, because mobile device sensors are generally of a lower performance and cost than dedicated sensors, sensor calibration is crucial. To enable more accurate measurements of natural phenomena through the use of mobile device sensors, we propose a hybrid sensor calibration scheme for such sensors; the scheme makes use of mobile device sensors and existing sensing infrastructure, such as weather stations, to obtain dense data. Simulation results show that the proposed scheme supports low mean square errors. As a practical application of our proposed scheme, we built a temperature map of a city using six mobile phone sensors and six reference sensors. Thanks to the mobility of the sensors and the proposed scheme, our map presents more detailed information than infrastructure-based measurements.

• Korean Journal of Remote Sensing
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• v.19 no.1
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• pp.81-89
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• 2003

A provision of spatial information is expected to make a market explosion in various fields. A distribution of spatial data on wireless mobile environments indicates a huge expansion of mobile technology as well as a spread of geospatial applications. For high-qualified spatial information, the 4S technology Project that is integrating four kinds of spatial systems is currently being executed with the goal of nationwide integration of spatial data and spatial information systems. In terms of network environments, a mobile ad hoc network where mobile terminals communicate with each other without any infrastructures has been standardized for the next generation mobile wireless network. With respect to the future technologies for spatial information, it is necessary to design 4S applications on mobile ad hoc networks. This paper addresses the issue, which is proposing design concepts for distributing 4S spatial data on mobile ad hoc networks and for ad hoc styled 4S applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4044-4062
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• 2016

We investigate the optimization of energy consumption in Mobile Cloud environment in this paper. In order to optimize the energy consumed by the CPUs in mobile devices, we put forward using the asymptotic time complexity (ATC) method to distinguish the computational complexities of the applications when they are executed in mobile devices. We propose a multi-scale scheme to quantize the channel gain and provide an improved dynamic transmission scheduling algorithm when offloading the applications to the cloud center, which has been proved to be helpful for reducing the mobile devices energy consumption. We give the energy estimation methods in both mobile execution model and cloud execution model. The numerical results suggest that energy consumed by the mobile devices can be remarkably saved with our proposed multi-scale scheme. Moreover, the results can be used as a guideline for the mobile devices to choose whether executing the application locally or offloading it to the cloud center.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.844-849
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• 2002

A provision of spatial information is expected to make a market explosion in various fields. A distribution of spatial data on wireless mobile environments indicates a huge expansion of mobile technology as well as a spread of geospatial applications. For high quality spatial information, 4S technology project integrating 4 kinds of spatial systems is currently being executed with the goal of nationwide integration of spatial data and spatial information systems. In terms of network environments, a mobile ad hoc network where mobile terminals communicate with each other without any infrastructures has been standardized for the next generation mobile wireless network. With respect to the future technologies for spatial information, it is necessary to design 4S applications on mobile ad hoc networks. This paper addresses the issue, which is proposing design points for distributing 4S spatial data on mobile ad hoc networks and ad hoc styled 4S applications.