• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1836-1839
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• 2005

We have developed Ethernet based real-time communication systems called "Vnet/IP" for DCS which is the control system for process automation. This paper describes the features and the technologies of the ASIC which is utilized in the communication interface hardware for Vnet/IP. Vnet/IP has been developed for mission-critical communications. Hence it has real-time feature, high reliability and precise time synchronization capability. At the same time, it is able to deal with standard protocols without influence on mission-critical communications. The communication interface hardware has a host interface and dual redundant network interfaces. The host interface can be chosen PCI-bus or R-bus which is the proprietary internal bus developed for the high reliable redundant controller. Each network interface is a RJ45 connection with 1Gbps maximum in compliance with IEEE802.3.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.414-414
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• 2000

This paper presents a method for building a real-time kernel of autonomous mobile robot control systems. Until now, most of robots have their own operation softwares dedicated only for their use. Sometimes, operation softwares were developed based on MS-DOS or other real -time kernel based on UNIX. However, MS-DOS has many restrictions for use as a robot operation system. Also, mix based real-time kernel has some Limitations for use with mobile robots. So, in this paper, we focus on building a real-time kernel based on Linux. The in this paper, the software modules of Task Management, Memory Management, Intertask Communication, and Synchronization are redesigned. To show the efficiency of the paper, it was applied to run Nomad Super Scout II avoiding obstacles detected by sonar sensor array.

• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.10-15
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• 2004

For effective conservation of the oceans and harbors, long-term and systematic development of the ocean and harbor monitoring system is essential. A monitoring system capable of real-time and accurate data acquisition is necessary for dealing with the level of contamination by situations, such as red tide and foods. This paper introduces an effective and economical real-time harbor environmental monitoring system that utilizes PCS wireless data communication technology. The monitoring system has various functions, such as multiple communication, TCP/IP protocol for wireless internet access, system time synchronization, and bi-directional communication between the measuring device and the server. The system has been implemented at Shinseondae harbor pier in Busan to validate the system's stability and effectiveness in data acquisition. The acquired real-time ocean and harbor environmental data is expected to have a large effect, when shared with the public through the Internet.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.63-68
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• 2003

For effective conservation of ocean and harbor, long-term and systematic development of the ocean and harbor monitoring system is essential. The monitoring system capable of real-time and accurate data acquisition is necessary for dealing with contamination such as red tide and the flood. This paper introduces the effective and economical real-time harbor environmental monitoring system that utilizes PCS wireless data communication technology. The monitoring system has various functions such as multiple communication, TCP/IP protocol for wireless internet access, system time synchronization, bi-directional communication between the measuring device and the server. The system has been implemented at Shinseondae harbor pier in Busan to validate the systems stability and effectiveness in data acquisition. The acquired real-time ocean and harbor environmental data is expected to have a large effect, when shared by public through internet.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.68-70
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• 1998

본 논문에서는 클록들을 주기적으로 동기화하는 분산 실시간 시스템에서 주어진 태스크의 시간 제약(timing constraint)을 변환시는 구가지 기법을 제안한다. 전형적인 이산 클록 동기화(discrete clock synchronization)알고리즘은 클록의 값을 순간적으로 보정(correct)하여 클록의 시간이 불연속적으로 진행학 한다. 이러한 시간상의 불연속성은 태스크의 시작제한시간(release time)이나 종료시한(deadline)과 같은 이벤트를 잃어버리거나 다시 발생시키는 오류를 범하게 한다. 클록 시간의 불연속성을 피하기 위해 일반적으로 연속 클록 동기화(continuous clock synchronization) 기법이제안되었지만 소프트웨어적으로 구현되기에는 많은 오버헤드를 유발시키는 문제점이 있다. 이에 따라 연속 클록 동기화는 PLL (Phase-Locked Loop)을 이용한 별도의 하드웨어를 사용하는 것이 보통이다. 본 논문에서는 연속 클록 동기화 기법을 사용하는 대신, 태스크의 시간 제약을 동적으로 변환시키는 DCT (Dynamic Constraint Transformation) 기법을 제안하였다. DCT는 소프트웨어 으로 구현이 가능하여 새로운 하드웨어를 필요로 하지 않으며, 이를 통해 기존의 이산적으로 동기화된 시스템에서 클록 시간의 불연속성에 의한 문제점들을 해결할 수 있다. 또 다른 문제점으로서, 클록의 물리적인 특성으로 인해 동기화된 클록들이 상한된(bounded from the above)오차(skew)를 갖는다는 것이다. 이러한 오차는 지역 클록(local clock)에 대해 만족될 수 있는 임의의 실기간 제약 조건이 전역 클록(global clock)에 대해서는 만족되지 않을 수 있음을 의미한다. 본 논문에서는 이를 위해 먼저 두 가지의 스케줄링 가능성, 지역적 스케줄링 가능서(local schedulability)과 전역적 스케줄링 가능성(global schedulability)을 정의하고, 실시간 제약을 정적으로 변환시키는 SCT (Static Constraint Transformation)기법을 제안하였다. SCT를 통해 지역적으로 스케줄링 가능한 태스크는 전역적으로 스케줄링이 가능하므로, 단지 지역적 스케줄링 가능성만을 검사하면서 스케줄링 문제를 해결할 수 있도록 하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.15-21
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• 2007

In this paper, we propose a technique of a practical symbol acquisition and tracking using a low complex ADC and simple digital circuits for noncoherent asynchronous impulse-radio-based Ultra Wideband (IR-UWB) receiver based on energy detection. Compared to previous approaches of detecting an exact acquisition time that require much hardware resource, the proposed technique is to detect the target symbol by finding the symbol acquisition interval per symbol with a target symbo, thus the complexity of the complete signal processing and power consumption by ADC are reduced. To do this, we define the bit decision window (BDW) and analyze the relation between SNR, hardware resource, size of BDW and BER(Bit Error Rate). Using the results, the optimum BDW size for the minimum BER with limited hardware resource is selected. The proposed synchronization technique is verified with an aid of a simulator programmed by considering practical impulse channels.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.37-45
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• 2007

A lot of conventional algorithms has tried to cancel the Residual Frame Synchronization Error (RFSE), which causes the performance degradation of channel estimation when using interpolation in lattice-type pilot-aided Time Division Duplex (TDD) OFDM systems. Among them, a pre- and post-compensation method has been attractive to eliminate the effects of RFSE, providing good performance but requiring high computational complexity. In this paper we propose a new method which lowers computational costs by adjusting the starting point of TDD OFDM systems' FFT window in order to compensate for the RFSE. For the performance verification, we apply the proposed method to IEEE 802.16e standard and also estimate additionally required computational power of it compared to the pre- and post-compensation method. Simulation and implementation results show that the proposed algorithm has performance similar to the conventional method and is very efficient with low power implementation, requiring only 4.9 % of the power which the conventional method needs additionally.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.56-65
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• 2006

In this paper, we introduce modified difference type symbol timing detection method of simple structure and show the relations between S/N ratio and timing detection performance which less influenced by multipath channel delay profile and added noise level and it show very exact GI detection performance characteristics. In the computer simulations, 4 symbol time duration of short and long training of IEEE802.11a standard OFDM frame are used for symbol synchronization timing detection. The computer simulation results show the very exact symbol timing detection performance characteristic within 1 sample error of OFDM signal regardless channel delay profile from minimn phase channels of phase rotation ${\pi}/2$ to non-minimum phase channels of phase rotation ${\pi}/2$ of received OFDM signal and added noise level in channel.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.540-546
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• 2008

In the near future, robots should be able to understand human's emotional states and exhibit appropriate behaviors accordingly. In Human-Human Interaction, the 93% consist of the speaker's nonverbal communicative behavior. Bodily movements provide information of the quantity of emotion. Latest personal robots can interact with human using multi-modality such as facial expression, gesture, LED, sound, sensors and so on. However, a posture needs a position and an orientation only and in facial expression or gesture, movements are involved. Verbal, vocal, musical, color expressions need time information. Because synchronization among multi-modalities is a key problem, emotion expression needs a systematic approach. On the other hand, at low intensity of surprise, the face could be expressed but the gesture could not be expressed because a gesture is not linear. It is need to decide the emotional boundaries for effective robot behavior generation and synchronization with another expressible method. If it is so, how can we define emotional boundaries? And how can multi-modality be synchronized each other?

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.37-48
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• 2004

The SyncML, the standard synchronization protocol, supports the synchronization of various application services between a client and a server such as an address book, a calendar. Even with this standard protocol, SyncML application developers usually spend a long time and efforts implementing service specific logics and databases. This paper designed and implemented the SDE(Service Development Environment) which is an integrated development environment for SyncML server developers to develop an application service rapidly and correctly. The SDE consists of two components i.e., the Sync Library and the SEG(Sync Engine Generator) tool. To prove the applicability of this study we implemented a SyncML server by using the SDE and also carried out the correctness tests and the performance test. We hope this system helps developers implement mobile application services more efficiently.