• 센서학회지
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• 제16권1호
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• pp.52-61
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• 2007

Networked embedded systems using the smart device and fieldbus technologies are now found in many industrial fields including process automation and automobiles. However the discrepancy between a node's view of current time and the rest of the system can cause many difficulties in the design and implementation of a networked system. To provide a networked system with a global reference time, the problem of clock synchronization has been intensively studied over the decades. However, many of the existing solutions, which are mainly developed for large scale distributed computer systems, cannot be directly applied to embedded systems. This paper presents a fault-tolerant clock synchronization technique that can be used for a low-cost embedded system using a CAN bus. The effectiveness of the proposed method is demonstrated with a set of microcontrollers and DC motor-based actuators.

• 대한임베디드공학회논문지
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• 제4권2호
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• pp.97-102
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• 2009

In this paper, the problem of stability analysis for networked control systems with norm-bounded parameter uncertainties is investigated. By construction Lyapunov's functional, a new delay-dependent stability criterion for uncertain networked control system is established in terms of LMIs (linear matrix inequalities) which can be easily by various convex optimization algorithms. One numerical example is included to show the effectiveness of proposed criterion.

• 대한임베디드공학회논문지
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• 제9권1호
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• pp.33-41
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• 2014

This paper presents a IEEE1588 based clock synchronization technique for a sRIO (Serial RapidIO) network which is applied to a submarine system. Clock synchronization plays a key role in the success of a networked embedded system. Recently, the IEEE1588 algorithm making use of dedicated chipset has been widely used for the synchronization of various industrial applications. However, there is no chipset available for the sRIO network that can offer many advantages, such as low latency and jitter. In this paper, the IEEE1588 algorithm for a sRIO network is implemented using only software without any dedicated chipset. The proposed approach is verified with experimental setup.

• 대한임베디드공학회논문지
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• 제13권1호
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• pp.9-15
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• 2018

This paper describes the applicability of Bluetooth and ZigBee networks for real-time control in wireless networked control system and suggests an effective usage of them. The Bluetooth SCO link, SPP and HID profiles and the ZigBee non-beacon enabled network are analyzed and the latency of them are measured. A number of wireless networked control system experiments are performed via DC motor control system and the various profiles of Bluetooth and ZigBee in real-time wireless networked control system are compared.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.302-308
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• 2006

We introduce the concept of a remote distributed embedded system to integrated fieldbus based control systems in internet/Intranet. As a result fieldbus systems are opened up for remote monitoring, remote maintenance, and remote control applications using state of the art Web-technology. This paper addresses the design of a remote distributed embedded system using Internet and CAN for multi-Induction motor of Building and Industrial field. The fieldbus used the CAN based networked intelligent multi-motor control system using DSP2812 microprocessor. To build such a system, the TCP/IP-CAN Gateway which convert a CAN protocol to TCP/IP protocol and vice verse, was designed. A experimental simulation system consists of a TCP/IP-CAN Gateway in remote place and a command PC ti be connected ti Ethernet.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.184-188
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• 2009

To interactively share High Definition (HD)-quality visualization over emerging ultra-high-speed network infrastructure, several lossless and low-delay real-time media (i.e., uncompressed HD video and audio) transport systems are being designed and prototyped. However, most of them still rely on expensive hardware components. As an effort to reduce the building cost of system, in this paper, we propose the integration of both transmitter and receiver machines into a single bi-directional transport system. After detailed bottleneck analysis and subsequent refinements of embedded software components, the proposed integration can provide Real-time Transport Protocol (RTP)-based bi-directional transport of uncompressed HD video and audio from a single machine. We also explain how to interface the Gbps-bandwidth display output of uncompressed HD media system to the networked tiled display of 10240 $\times$ 3200 super-high-resolution. Finally, to verify the feasibility of proposed integration, several prototype systems are built and evaluated by operating them in several different experiment scenarios.

• 대한임베디드공학회논문지
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• 제6권3호
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• pp.149-156
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• 2011

Transmission delay and packet loss induced by a communication network can degrade the control performance and, even make the system unstable. This paper presents a method for compensating transmission delay and packet loss in a networked control system for unmanned underwater vehicle. The proposed method is based on Lagrange interpolation in order to satisfy the requirements of simplicity and model-independency. In this work, the lost/delayed data are estimated in real time by only using the past data without requiring any mathematical model of the controlled system. Consequently, the proposed method can be implemented independent of the controlled system, and also it can achieve fast and accurate compensation performance. The performance of the proposed technique is evaluated by numerical simulations with an unmanned underwater vehicle.

• 대한임베디드공학회논문지
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• 제15권2호
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• pp.103-109
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• 2020

This paper finds solutions for using ZigBee in wireless networked control system (WNCS). The round trip time delay and packet loss rate of the WNCS are measured. On the basis of these measured data, a playback buffer is used to solve the variable time delay in WNCS, and a Smith predictor is introduced to compensate for the time delay. The WNCS was able to be actually constructed to perform DC motor position control with 40 Hz sampling frequency.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권4호
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• pp.288-298
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• 2008

We introduce new type of networked robot, Ubiquitous Robotic Companion (URC), embedded with ATLAS Service-oriented architecture for enhancing the space sensing capability. URC is a network-based robotic system developed by ETRI. For years of experience in deploying service with ATLAS sensor platform for elder and people with special needs in smart houses, we need networked robots to assist elder people in their successful daily living. Recently, pervasive computing technologies reveals possibilities of networked robots in smart spaces, consist of sensors, actuators and smart devices can collaborate with the other networked robot as a mobile sensing platform, a complex and sophisticated actuator and a human interface. This paper provides our experience in designing and implementing system architecture to integrate URC robots in pervasive computing environments using the University of Florida's ATLAS service-oriented architecture. In this paper, we focus on the integrated framework architecture of URC embedded with ATLAS platform. We show how the integrated URC system is enabled to provide better services which enhance the space sensing of URC in the smart space by applying service-oriented architecture characterized as flexibility in adding or deleting service components of Ubiquitous Robotic Companion.

• 조명전기설비학회논문지
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• 제21권1호
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• pp.82-90
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• 2007

이 논문은 유도전동기 원격제어를 위한 분산 임베디드시스템에 관한 연구로 제어시스템은 CAN통신을 기반으로 하는 네트워크를 구성하였으며 원격제어를 위하여 Ethernet TCP/IP-CAN 게이트웨이를 개발하였다. 이를 통하여 유도전동기 2대의 구동시스템을 제작하여 원격제어실험을 수행하였으며 실험 결과 개발된 알고리즘 및 TCP/IP-CAN 게이트웨이가 매우 우수한 성능을 가지고 있음을 확인하였다.