• 대한기계학회논문집A
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• 제25권3호
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• pp.486-494
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• 2001

This paper presents a real-time multibody vehicle dynamic analysis method using recursive Kanes formulation and suspension composite joints. To shorten the computation time of simulation, relative coordinate system is used and the equations of motion are derived using recursive Kanes formulation. Typical suspension systems of vehicles such as MacPherson strut suspension system is modeled by suspension composite joints. The joints are derived and utilized to reduce the computation time of simulation without any degradation of kinematical accuracy of the suspension systems. Using the develop program, a multibody vehicle dynamic model is formed and simulations are performed. Accuracy of the simulation results is compared to the real vehicle field test results. It is found that the simulation results using the proposed method are very accurate and real-time simulation is achieved on a computer with single PowerPC 604 processor.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.69-74
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• 2003

This study is aimed to develop a system to position and manage object flow in real time. Logistics management system which position objects and vans using GPS is required to load, unload and keep freight effectively and in real time at sea or airport. In this study, a management system which is consisted of five sub-systems is developed; GPS position analysis system, GPS interface system, mapping system, network system and database management system.

• 정보처리학회논문지A
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• 제18A권6호
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• pp.271-280
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• 2011

실시간 소프트웨어 설계 구조 중의 하나인 시간 구동 구조 (TTA: Time-Triggered Architecture)는 미리 정해진 시간에 따라 특정 태스크를 수행하기 때문에 소프트웨어의 동작을 예측하기 쉽지만 이의 적용을 위해서는 시스템의 시간 제약성을 만족시키는 설계 과정이 필수적이다. 반면 이벤트 구동 구조 (ETA: Event-Triggered Architecture)는 외부의 이벤트가 발생함에 따라 대응되는 태스크를 수행하는 방식으로 소프트웨어의 구조가 직관적이고 이벤트에 대한 반응 시간이 빠르며 확장이 용이하다. 그러나 이 구조는 다양한 이벤트 발생 상황에 대한 시스템 동작의 예측이 어려워서 높은 안전도가 필요한 시스템 구현에 많이 사용되고 있지 않다. 많은 관련 연구에서 높은 안전도가 필요한 안전 지향 시스템에 TTA를 적용 할 것을 권장되지만, 실제 구현에 있어서는 이의 적용에 필요한 실시간성 분석에 많은 노력이 소요되고, 소프트웨어 공학기술 적용에 대한 인식 부족으로 TTA의 적용이 많지 않은 실정이다. 본 논문은 인간의 생명과 직결되어 이에 따른 실시간성과 안전성이 요구되는 인공심장 제어 시스템에 내장된 소프트웨어 구조를 TTA 기반으로 개선한 연구를 기술한다. 본 연구에서는 인터럽트 측정 소프트웨어를 구현하여 기존에 내장된 실시간 소프트웨어가 가진 태스크의 시간적 속성을 파악하고 RMA (Rate-Monotonic Analysis) 실시간 분석 기법을 통해 시스템의 실시간성을 만족할 수 있도록 설계를 개선하였다. 또한, 이를 바탕으로 인공심장 제어 소프트웨어의 구현을 개선하여 다양한 실험을 통해 개선된 TTA 기반의 소프트웨어를 탑재한 인공심장 시스템은 시스템의 동작 예측도를 획기적으로 높여주면서 기존의 인공심장 시스템과 동일하게 동작함을 확인하였다.

• 제어로봇시스템학회논문지
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• 제6권1호
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• pp.15-24
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• 2000

Stand-alone global position system receiver based on C/A code tracking generates position error of 100m mainly due to the selective availability and ionospheric and tropospheric delay errors. The differential GPS is the most commonly used method for removing those bias range error components. The relative GPS, although somewhat restrictive in its use, is ideally suited to the car monitoring system for improved Automatic Vehicle location, especially where the DGPS infrastructure is not available. The RGPS does not require any additional hardware, facility or external infrastructure and can be operated within the system with existing host computer and communication link. This paper presents detailed description of the RGPS concept and its implementation for real-time data processing. Performance of RGPS is evaluated with real data and is compared with DGPS.

• 전기학회논문지
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• 제59권2호
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• pp.242-247
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• 2010

This paper introduces a real-time load flow program for Korean energy management system(EMS). This study is concentrated on the following aspects. First, we propose the model of the real-time database and power system equipment for the real-time load flow. These models are extracted from the needs of load flow functions and are designed to the application common information. Second, several techniques are applied for the efficient convergence and computational speed. The generation/load mismatch is redistributed using generator participation factors which are separated to the reference bus. For the voltage control, the jacobian matrix is composed with the basic Y matrix elements and the voltage control elements. Through the optimally ordering, jacobian row and column for a column is changed. However all jacobian matrix entries have same order with the Y matrix. The proposed program is tested using the Korea Electric Power Corporation(KEPCO) system. Through the test, we verified that the proposed program can be effectively used to accomplish the Korean EMS system.

• 대한전기학회논문지:전력기술부문A
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• 제55권11호
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• pp.476-484
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• 2006

The failure prediction and preventive maintenance for the equipment of nuclear power plant area using reliability-centered maintenance have been grown. On the other hand, the maintenance for power distribution system consists of time-based maintenance mainly. In this paper, the new maintenance algorithms for power distribution system are developed considering reliability indices. First of all, Time-varying failure rates are extracted from data accumulated at KEPCO using exponential distribution function and weibull distribution function. Next, based on the extracted failure rate, reliability for real power distribution system is evaluated for applying the effective maintenance algorithm which is the analytic method deciding the maintenance point of time and searching the feeder affecting the specific customer. Also the algorithm deciding the maintenance priority order are presented based on sensitivity analysis and equipment investment plan are analyzed through the presented algorithm at real power distribution system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.58-63
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• 1998

B.Widrow established fundamental relations between the least-mean-square (LMS) algorithm and the digital Fourier transform［1］. By extending these relations, we proposed the short time spectra analysis system using the LMS algorithm［2]. In that paper, we used the normal LMS algorithm on the thought of dealing with only real analytical signal. This algorithm minimizes the real mean-square by recursively altering the complex weight vector at each sampling instant. But, the short time spectra analysis sometimes deals with the complex signal that is outputted from complex analog filter. So, in order to optimize and develop this methods, furthermore it is necessary to derive an algorithm for the complex analytical signal. In this paper, we first discuss the new adaptive system for the spectra analysis using the complex LMS algorithm and then derive convergence condition, time constant of coefficient adjustment and frequency resolution by extending the discussion. Finally, the effectiveness of the proposed method is experimentally demonstrated by applying it to the measurement of transfer performance on complex analog filter.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.167-176
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• 2023

This study presents the performance analysis of real-time orbit determination and prediction for navigation message generation of Regional Navigation Satellite System (RNSS). Since the accuracy of ephemeris and clock correction in navigation message affects the positioning accuracy of the user, it is essential to construct a ground segment that can generate this information precisely when designing a new navigation satellite system. Based on a real-time architecture by an extended Kalman filter, we simulated orbit determination and prediction of RNSS satellites in order to assess the accuracy of orbit and clock prediction and signal-in-space ranging errors (SISRE). As a result of the simulation, the orbit and clock accuracy was at 0.5 m and 2 m levels for 24 hour determination and six hour prediction after the determination, respectively. From the prediction result, we verified that the SISRE of RNSS for six hour prediction was at a 1 m level.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.557-564
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• 2001

The objective of he study is to record the real conditions along with the soccer ball that is, each player's ball keeping time, the number football keeping, accuracy of passing to other player, direction, etc., on a real-time basis, measure them in numbers and get necessary analyzed output as much as one needs. The study consists of the following stages: (1) Record the data by drawing through Visual Interface on a real-time basis; (2) Graphic windows to display the recorded data item by item in graphic; (3) Form windows to display the individual or team scores anytime when needed; (4) Windows to display the analyzed data in visualized form. The effect of the study is threefold: (1) It inputs all the game-related data on a real-time basis, which was impossible before and shows analyzed contents during the game enabling each tea manager o use; (2) In cse of TV broadcasting or newspaper articles, it explains objectively the situations of he game to the TV viewers or readers; (3) After the game, it provides importance information on each team's playing ability and individual player's technical improvement through data analysis.

• Journal of Electrical Engineering and information Science
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• 제1권1호
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• pp.118-128
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• 1996

In safety critical hard real-time systems, a timing fault may yield catastrophic results. In order to eliminate the timing faults from the fast responsive real-time control systems, it is necessary to schedule a code based on high precision timing analysis. Further, the schedulability enhancement by having multiple processors is of wide spread interest. However, although an instruction level parallel processing is quite effective to improve the schedulability of such a system, none of the real-time applications employ instruction level parallel scheduling techniques because most of the real-time scheduling models have not been designed for fine-grain execution. In this paper, we present a timing constraint model specifying high precision timing constraints, and a practical approach for constructing static schedules for a VLIW execution model. The new model and analysis can guarantee timing accuracy to within a single machine clock cycle.