• Journal of KIISE:Computer Systems and Theory
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• v.37 no.1
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• pp.35-42
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• 2010

Guest operating systems running over the virtual machines share a variety of resources. Since CPU is allocated in a time division manner it consequently leads them to having the unknown physical time. It is not regarded as a serious problem in the server virtualization fields. However, it becomes critical in embedded systems because it prevents guest OS from executing real time tasks when it does not occupy CPU. In this paper we propose a hypercall to register a timer service to notify the timer request related real time. It enables hypervisor to schedule a virtual machine which has real time tasks to execute, and allows guest OS to take CPU on time to support real time. The following experiment shows its implementation on Xen-Arm and para-virtualized Linux. We also analyze the real time performance with response time of test application and frames per second of Mplayer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.5
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• pp.271-279
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• 2014

In this paper, the two design techniques of the embedded system which provides a wireless image observation with temporary ad-hoc network are proposed and developed. The first method is based on the embedded system design technique for a nearly real-time wireless short observation application, having a specific remote monitoring node with a built-in image processing function, and having the maximum rate of 1 fps (frame per second) wireless image transmission capability of a $160{\times}128$size image. The second technique uses the embedded system for a general wireless long observation application, consisting of the main node, the remote monitoring node, and the system controller with built-in image processing function, and the capability of the wireless image transmission rate of 1/3 fps. The proposed system uses the wireless ad-hoc network which is widely accepted as a short range, low power, and bidirectional digital communication, the hardware are consisted of the general developed modules, a small digital camera, and a PC, and the embedded software based upon the Zigbee stack and the user interface software are developed and tested on the implemented module. The wireless environment analysis and the performance results are presented.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.3
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• pp.141-152
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• 2007

In this paper, we present a network-oriented lightweight real-time system, which is composed of an event-driven operating system called the Embedded Lightweight Operating System (ELOS) and a generic multi hop ad hoc routing protocol suite. In the ELOS, a conditional preemptive FCFS scheduling method with a guaranteed time slot is designed for efficient real-time processing. For more elaborate configurations, we reinforce fault tolerance by supplementing semi-auto configuration using wireless agent nodes. The developed hardware platform is also introduced, which is a scalable prototype constructed using off-the-shelf components. In addition, in order to evaluate the performance of the proposed system, we developed a ubiquitous network test-bed on which several experiments with respect to various environments are conducted. The results show that the ELOS is considerably favorable for tiny ubiquitous networked systems with real-time constraints.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.30-37
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• 2007

Hardware for monitoring the water quality is developed using water fleas. Water flea is a frequently used biological sensor for monitoring the water quality. Water fleas quickly respond to the incoming toxic water by changing their activity when they are exposed. By measuring the activity of water fleas, the incoming toxic water is instantly detected in real time. So far the measurement of activity of water fleas has been done with a system equipped with a light source of LED and a light detector of photo transistor. Water flea itself is, however, sensitive to light resulting in incorrect response and the system has two inconvenient separate parts of the light source and the detector. This paper suggests a system using a CCD camera instead of a light source and a detector. The suggested system processes the image data from the CCD camera in real time without any delay. The developed system becomes a part of the remote water monitoring embedded system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.418-420
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• 2012

최근 자동차 산업의 활성화로 인해 교통사고가 문제화 되면서 사고를 미연에 방지할 수 있는 운전자 보조시스템 연구가 활발하게 이루어지고 있다. 그 중 AVM 시스템(Around-View Monitoring System)에 대한 연구 및 개발이 활발해 지고 있다. 기존 AVM 시스템은 차량 주변 상황을 실시간으로 제공하기 위해 임베디드 시스템 또는 SoC(System on Chip)의 형태로 개발되었다. 그러나 Car PC가 차량에 장착되면 AVM 시스템을 추가의 비용이 없이 소프트웨어만으로 시스템을 개발할 수 있다. 본 논문에서는 Car PC 기반의 AVM 시스템 기능에 위치 정보 기능을 추가하여 위치정보를 제공하는 AVM 시스템을 구현하고자 한다.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.365-374
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• 2005

Schedulability analysis is necessary to build reliable embedded real-time systems. For schedulability analysis, worst-case execution time(WCET) analysis that computes upper bounds of the execution times of tasks, is required indispensably. WCET analysis is done in two phases. The first phase is high-level analysis that analyzes control flow and finds longest paths of the program. The second phase is low-level analysis that computes execution cycles of basic blocks taking into account the hardware architecture. In this thesis, we design and implement integrated WCET analysis tools. We develop the WCET analysis tools for XScale-based system called WATER(WCET Analysis Tool for Embedded Real-time system). WATER consist of high-level flow analyzer and low-level execution time analyzer. Also, We compare real measurement for execution of program with analysis result calculated by WATER.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.791-799
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• 2008

An image recognition for surrounding conditions is very important in image transmission. In recently rears, as the information infrastructure is more general, the user-centered demands in which they want to identify by object's states image using wire or wireless environment have increased. However, existing mobile solution could be hard to expect high quality mage, because limitation of software processing according as network based on mobile terminal which has low band width supports software codec. To solve this weak point, this paper describes on hardware codec design based on MPEG-4 which is international video compression standard. Implemented system contains the embedded CPU for optimized design and it works high quality service as transmission speed and resolution in mobile circumstance.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.27-32
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• 2008

This paper presents the implementation of simple genetic algorithm using hardware description language for evolvable hardware embedded system. Evolvable hardware refers to hardware that can change its architecture and behavior dynamically and autonomously by interacting with its environment. So, it is especially suited to applications where no hardware specifications can be given in advance. Evolvable hardware is based on the idea of combining reconfigurable hardware device with evolutionary computation, such as genetic algorithm. Because of parallel, no function call overhead and pipelining, a hardware genetic algorithm give speedup over a software genetic algorithm. This paper suggests the hardware genetic algorithm for evolvable embedded system chip. That includes simulation results for several fitness functions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.363-372
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• 2016

SIGMA(Scientific cubesat with Instruments for Global Magnetic field and rAdiation) CubeSat has been developed for magnetic field measurement of the Earth and space radiation measurement at Kyung Hee university. The flight software plays important roles in controlling the satellite and processing the data in the space mission. In this paper, the Flight Software has been implemented to process all the tasks in the one thread without RTOS(Real Time Operating System). This is an effective mothed not only to concentrate the space mission of CubeSat but also to reduce the overhead of the Flight Software by considering the mission perform procedures and the system control methods.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.1-13
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• 2024

This study aims to provide a customized dynamic kiosk screen that considers user characteristics to cope with changes caused by increased use of kiosks. In order to optimize the screen composition according to the characteristics of the digital vulnerable group such as the visually impaired, the elderly, children, and wheelchair users, etc., users are classified into nine categories based on real-time analysis of user characteristics (wheelchair use, visual impairment, age, etc.). The kiosk screen is dynamically adjusted according to the characteristics of the user to provide efficient services. This study shows that the system communication and operation were performed in the embedded environment, and the used object detection, gait recognition, and speech recognition technologies showed accuracy of 74%, 98.9%, and 96%, respectively. The proposed technology was verified for its effectiveness by implementing a prototype, and through this, this study showed the possibility of reducing the digital gap and providing user-friendly "barrier-free kiosk" services.