• 한국통신학회논문지
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• 제25권9A호
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• pp.1340-1347
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• 2000

The international mobile telecommunication-2000(IMT-2000) system can support not only the non-realtime multimedia traffic such as data such as data image but also the realtime multimedia traffic such as voice, video. In the paper we propose multicode allocation and handoff schemes for efficient transmission of realtime and non-realtime data in cdma2000. In those schemes the bandwidth of target cell is reserved based on moving direction of mobiles to support QoS of realtime multimedia data and the reserved bandwidths is used by the non-realtime mobiles of the target cell until the mobiles want to perform hadoff. Our framework is able to guarantee QoS continuity of realtime multimedia data and carries the maximum number of subscriber. System performance is evaluated and compared with conventional scheme considering transmission delay channel utilization and blocking probability by computer simulation.

• KIEE International Transactions on Power Engineering
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• 제3A권2호
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• pp.93-99
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• 2003

This paper deals with the development and testing of a large-scale, realtime digital power system simulator for the Korean Electric Power Corporation. The KEPS Simulation Center is located at KEPCO's research center (KEPRI) in Taejon, South Korea and has been operated since September 2001. The KEPS Simulation Center includes a wide range of off line power system simulation and analysis tools, as well as an advanced realtime digital simulator for the study of large scale AC and DC system performance. Because the application scope of the KEPS realtime simulator is broad and because the network models being considered are significantly larger and more complex than in traditional realtime simulator applications, many developments and tests have been required during the course of the project. In this paper, the authors describe some of these developments and present results from various benchmark tests that have been performed.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.73-78
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• 2003

In this research, we implement Realtime Air Diffusion Prediction System which is a parallel Fortran model running on distributed-memory parallel computers. The system is designed for air diffusion simulations with four-dimensional data assimilation. For regional air quality forecasting a series of dynamic downscaling technique is adopted using the NCAR/Penn. State MM5 model which is an atmospheric model. The realtime initial data have been provided daily from the KMA (Korean Meteorological Administration) global spectral model output. It takes huge resources of computation to get 24 hour air quality forecast with this four step dynamic downscaling (27km, 9km, 3km, and lkm). Parallel implementation of the realtime system is imperative to achieve increased throughput since the realtime system have to be performed which correct timing behavior and the sequential code requires a large amount of CPU time for typical simulations. The parallel system uses MPI (Message Passing Interface), a standard library to support high-level routines for message passing. We validate the parallel model by comparing it with the sequential model. For realtime running, we implement a cluster computer which is a distributed-memory parallel computer that links high-performance PCs with high-speed interconnection networks. We use 32 2-CPU nodes and a Myrinet network for the cluster. Since cluster computers more cost effective than conventional distributed parallel computers, we can build a dedicated realtime computer. The system also includes web based Gill (Graphic User Interface) for convenient system management and performance monitoring so that end-users can restart the system easily when the system faults. Performance of the parallel model is analyzed by comparing its execution time with the sequential model, and by calculating communication overhead and load imbalance, which are common problems in parallel processing. Performance analysis is carried out on our cluster which has 32 2-CPU nodes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.654-659
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• 1993

In this paper, a robot controller that has a real time-multitasking OS (Operating System) is developed. It can do given jobs in realtime, so its effectiveness is increased. The controller has several CPU boards, and it is needed to communicate among these boards. For that reason, it is adopted VME bus system and VMEexec OS that can process multiprocess in realtime. Multiprocess includes robot language edit process, vision process, low level motion control process, and teach process in higher layer. And dynamics, kinematics, and inverse kinematics that require realtime calculation are included in lower layer.

• 한국정보통신학회논문지
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• 제3권1호
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• pp.75-82
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• 1999

무선 실시간 모니터링 시스템은 무선 모뎀, 중앙 모니터, 이동단말기, 데이터베이스 서버로 구성되며 환자의 이동성, 설치시간의 감소, 장기간으로 본 비용절감 등의 잇점을 제공한다. 또한 이 시스템은 환자 위치추적 서비스를 제공한다. 환자 위치 추적 서비스는 무선 모니터링 시스템의 경우 환자 이동중 위급 상황 발생시 응급 처치를 위해 반드시 제공되어야 한다. 본 논문에서는 개선된 CSMA/CA프로토콜과 환자 위치 추적 알고리즘을 제안하고 이를 이용하여 무선 실시간 모니터링 시스템을 구현하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.88-90
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• 2003

We implement Realtime Air Diffusion Prediction System which is designed for air diffusion simulations with four-dimensional data assimilation. For realtime running, we parallelize the system using MPI (Message Passing Interface) on distributed-memory parallel computers and build a cluster computer which links high-performance PCs with high-speed interconnection networks. We use 162­CPU nodes and a Myrinet network for the cluster

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.86-88
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• 2004

Personal Robot System in developing, have a module architecture, each module are connected through variety network system like ethernet, WLAN (802.11), IEEE 1394 (firewire), bluetooth, CAN, or RS-232C. In developing personal robot system. We think that the key of robot performance is interoperablity among modules. Each network protocol are well connected in the view of network system for the interoperability. So we make a bridging architecture that can routing converting, and transporting packets with matching each network's properties. Furthermore, we suggest a advanced design scheme for realtime / non-realtime and control signal (short, requiring hard-realtime) / multimedia data (large, requiring soft-realtime).

• 한국해양공학회지
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• 제25권6호
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• pp.116-122
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• 2011

A realtime simulator using an explicit integration method is introduced to improve the solving performance for the dynamic analysis of a wheeled vehicle. Because a full vehicle system has many parts, the development of a numerical technique for multiple d.o.f. and ground contacts has been required to achieve a realtime dynamics analysis. This study proposes an efficient realtime solving technique that considers the wheeled vehicle dynamics behavior with full degrees of freedom and wheel contact with soft ground such as sand or undersea ground. A combat vehicle was developed to verify this method, and its dynamics results are compared with commercial programs using implicit integration methods. The combat vehicle consists of a chassis, double wishbone type front and rear suspension, and drive train. Some cases of vehicle dynamics analysis are carried out to verify the realtime ratio.

• 정보처리학회논문지A
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• 제11A권1호
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• pp.21-28
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• 2004

본 논문에서는 실시간 리눅스 환경에서 상주형(residential) 게이트웨이의 설계와 핵심 기능들의 구현 방법에 대한 연구를 수행하였다. 기존 실시간 운영체계의 각 기능들에 관련된 최근의 연구 결과들을 활용하여 상주형 게이트웨이의 운영체계로서 실시간 리눅스론 안정적으로 실행시킬 수 있는 장치구동기(device driver)의 개발 사례를 제시하였으며, 시스템 내에서의 성능 특성을 정성적으로 분석하여 성능을 개선시킬 수 있는 방법을 설명하였다. 이를 통해 실시간 리눅스 환경에서 상수형 게이트웨이의 효율적인 구현 가능성을 제시하였다.

• 한국정밀공학회지
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• 제15권7호
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• pp.175-181
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• 1998

This paper describes realtime visual tracking system of moving object for three dimensional target using EKF(Extended Kalman Filter). We present a new realtime visual tracking using EKF algorithm and image prediction algorithm. We demonstrate the performance of these tracking algorithm through real experiment. The experimental results show the effectiveness of the EKF algorithm and image prediction algorithm for realtime tracking and estimated state value of filter, predicting the position of moving object to minimize an image processing area, and by reducing the effect by quantization noise of image.