• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.219-226
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• 2005

This paper describes the open API with integration of semantic web service with PARLAY X based open API in 4G mobile network. It can be expected that the intelligence such as the context-awareness, adaptation and personalization in 4G mobile network will be deployed. But the existing PARLAY based network lacks in considering context-awareness, adaptation and personalization. Therefore, the object of this paper is to support the architecture and the Application Programming Interface (API) of the network service for the context-awareness, adaptation and Personalization in 4G mobile network The open API is to provide users with the adaptive network service to the changing context constraints as well as detecting the changing context and user's Preference. For instance, the open API can Provide users with QoS in network according to the detected context and user's preference, after detecting the context such as location and speed and user's preference.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.780-788
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• 2011

This paper suggests one model, which can be monitor and control target system at anytime and anywhere by a WAP and ME based personal cellular phone(Feature phone) and internet connection. The suggesting model tried to overcome constraints of distance and mobility of conventional methods, TCP/IP based remote data monitoring system, which combine PDA and WLAN technologies. For the experiments of suggesting model, the target systems are constructed with individual modules, which need AC or DC power control. The development software for the control and monitor of local system use NI Labview for the easy-programming and confidence. Also, web server use APM setup for the general user. The mobile connection environments of personal cellular phone are programmed by use WML and mHTML language for the general access. Through the experiments, we have showed that suggesting model can overcome constraints of distance and mobility of conventional system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.673-676
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• 2005

In this paper, we propose a improved control performance for autonomous mobile robot using the embeded system. The proposed PID(PPID) control method removes steady state error, and has good performance in transient response. The integral term in the proposed method accumulates error in increment section, inverses errors in decrement section, and increases the effect of integral coefficient around target. Therefore, the PPID control method decreases the overshoot, and makes settling time faster than general PID(GPID) control method. In order to verify the effectiveness of the proposed method(PPID), we simulated the position control of DC motor, and experimented the velocity control of autonomous mobile robot. The PPID control method demonstrated good control performance that decrease overshoot and settling time in simulation and experiments.

• Annual Conference of KIPS
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• 2002.11a
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• pp.115-118
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• 2002

소켓 프로그래밍(socket programming) 인터페이스를 지원하는 C/C++, perl, python 과 같은 언어들은 폴링(polling) 기능을 갖는 select() 함수를 제공한다. 이 select()함수를 이용할 경우, 단일 쓰레드(또는 프로세스)로 다중의 클라이언트 요청을 처리할 수 있다. 최근 네트워크 프로그래밍 분야에서 주목받는 자바 언어의 경우, 최신 JDK 1.4 의 비동기 입출력 패키지에서 select()함수를 제공하고 있으나, JDK 1.3을 포함한 그 이하의 버전에서는 아직까지 이 함수를 제공하지 않고 있다. 일반적으로 다중 쓰레드를 이용하여 소켓서버 응용프로그램을 개발할 경우, 코드가 단순해지고 응답이 빠른 장점이 있는 반면에 네트워크 연결이 증가할수록 다수의 쓰레드를 관리하는 일이 CPU에 큰 부담이 된다. 반면에 소켓폴링(socket polling)을 사용할 경우, 이러한 연결 유지에 대한 부담이 줄어드는 대신, 다중 쓰레드를 이용하는 방법에 비하여 구현이 어렵다. 본 논문에서는 다양한 시뮬레이션 환경에서 세가지 소켓 프로그래밍 모델에 대하여 그 성능을 비교평가 하였다. 이 세가지 모델은 단순 다중 쓰레드 모델(typical multi-thread model), 단일 쓰레드 소켓폴링 모델(socket polling with single-thread model), 다중 쓰레드 소켓폴링 모델(socket polling with multi-threadmodel)이다. 본 논문에서는 다중 쓰레드 소켓폴링 모델을 제안하고 JDK 1.3.1을 이용하여 구현하였다. 이 모델의 경우 복잡한 구조에도 불구하고 단순 다중 쓰레드 모델와 유사하거나 더 나은 성능을 보여주었다. 또한 동일한 용량의 쓰레드 풀(thread pool)을 사용하더라도 단순 다중 쓰레드 모델보다 더 많은 수의 클라이언트를 수용할 수 있는 장점이 있다. 이러한 결과를 바탕으로 본 연구팀에서 수행중인 MoIM-Messge서버의 네트워크 모듈로 다중 쓰레드 소켓폴링 모델을 적용하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5701-5722
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• 2018

The continuous increase in the cost of energy production and concerns for environmental sustainability are leading research communities, governments and industries to amass efforts to reduce energy consumption and global $CO_2$ footprint. Players in the information and communication industry are keen on reducing the operational expenditures (OpEx) and maintaining the profitability of cellular networks. Meanwhile, network virtualization has been proposed in this regard as the main enabler for 5G mobile cellular networks. In this paper, we propose a generic framework of slice resource provisioning and customized physical resource allocation for energy-efficiency and quality of service optimization. In resource slicing, we consider user demand and population resources provisioning scheme aiming to satisfy quality of service (QoS). In customized physical resource allocation, we formulate this problem with an integer non-linear programming model, which is solved by a heuristic algorithm based on minimum vertex coverage. The proposed algorithm is compared with the existing approaches, without consideration of slice resource constraints via system-level simulations. From the perspective of infrastructure providers, traffic is scheduled over a limited number of active small-cell base stations (sc-BSs) that significantly reduce the system energy consumption and improve the system's spectral efficiency. From the perspective of virtual network operators and mobile users, the proposed approach can guarantee QoS for mobile users and improve user satisfaction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2496-2512
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• 2021

The requirements for powerful computing capability, high capacity, low latency and low energy consumption of emerging services, pose severe challenges to the fifth-generation (5G) network. As a promising paradigm, mobile edge networks can provide services in proximity to users by deploying computing components and cache at the edge, which can effectively decrease service delay. However, the coexistence of heterogeneous services and the sharing of limited resources lead to the competition between various services for multiple resources. This paper considers two typical heterogeneous services: computing services and content delivery services, in order to properly configure resources, it is crucial to develop an effective offloading and caching strategies. Considering the high energy consumption of 5G base stations, this paper considers the hybrid energy supply model of traditional power grid and green energy. Therefore, it is necessary to design a reasonable association mechanism which can allocate more service load to base stations rich in green energy to improve the utilization of green energy. This paper formed the joint optimization problem of computing offloading, caching and resource allocation for heterogeneous services with the objective of minimizing the on-grid power consumption under the constraints of limited resources and QoS guarantee. Since the joint optimization problem is a mixed integer nonlinear programming problem that is impossible to solve, this paper uses deep reinforcement learning method to learn the optimal strategy through a lot of training. Extensive simulation experiments show that compared with other schemes, the proposed scheme can allocate resources to heterogeneous service according to the green energy distribution which can effectively reduce the traditional energy consumption.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.297-302
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• 2008

In case of display a lot of information from mobile devices, those systems are being developed that display the information from mobile devices on remote devices such as TV using the mobile devices as remote controllers because it is difficult to display a lot of information on mobile devices due to their limited bandwidth and small screen sizes. A lot of cost is required to design and develop interfaces for these systems corresponding to each of remote display devices. In this paper, a mobile environment based remote display system for displays at real times is proposed for continuous monitoring of status data for unique 'Mote IDs'. Also, remote data are collected and monitored through sensor network devices such as ZigbeX by applying status perception based remote displays at real times through processing ubiquitous computing environment data, and remote display applications at real times are implemented through PDA wireless mobiles. The system proposed in this paper consists of a PDA for remote display and control, mote embedded applications programming for data collections and radio frequency, server modules to analyze and process collected data and virtual prototyping for monitoring and controls by virtual machines. The result of the implementations indicates that this system not only provides a good mobility from a human oriented viewpoint and a good usability of accesses to information but also transmits data efficiently.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.257-260
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• 2004

This paper describes the software download framework for SDR(Software Defined Radio). SDR is expected to solve the compatibility problem among various mobile communication standards so that people can use the same device for different wireless network. We integrated the SDR software download process into Jini architecture, and modified Jini's several functions. We implemented this proposed framework on a Linux and windows operating systems with Java programming language. With Java platform, we can easily transfer this framework into hand-held devices.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.121-129
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• 2017

In this study, we investigated a cooperative control system of assembly robots using wireless LAN. We developed two different types of robots to assemble three blocks on a workbench. Robot1 can assemble blocks on a workbench and Robot2 can carry blocks to Robot1. We constructed an ROS-based communication system and shared data. Three blocks and one workbench were recognized by camera-image processing By developing the UI using Windows programming language Visual C#, we evaluated the status of the robots and blocks and controlled the robots. The control system was developed by constructing all elements necessary for cooperative control, such as robot design and fabrication, motor control, ROS-based communication, and image processing. Thus, we completed fundamental tasks required for assembly.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.643-645
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• 2002

이동 에이전트는 분산 응용에 있어서 네트워크의 부하와 대기시간을 줄일 수 있는 좋은 기술 중 하나이며, 다양한 네트워크 환경에 대한 유연성과 보안성 좋아 향후 기대되는 환산 응용 기반 기술이라 할 수 있다. 본 논문에서는, 이동 에이전트 기반의 다양한 분산 응용에 효율적으로 적용할 수 있는 이동 에이전트 플랫폼인 HUMAN이 설계 구현되었다. 이동 에이전트 플랫폼, HUMAN은 파일 탐색, 그룹 어드레싱, 다양한 여정 모드, 유연 응답 기능 등의 고급 유틸리티 등을 지원하고 있어, 에이전트 프로그래밍에 있어서 높은 수월성을 제공하고 있으며, 불법파일 탐색 등과 같은 분산 응용에 특히 유용할 수 있다. 또한 에이전트 등록, 해지 등을 위한 관리 서버 등을 제공하고 있어, peer-to-peer관련 분산 응용 시스템의 개발에도 용이하게 적용할 수 있다는 장점을 가지고 있다.