• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.34 no.6
• /
• pp.230-237
• /
• 1985

Shortest path calculations for a large-scale network have to be performed using a decomposition techniqre, since the calculations require large memory size which increases by the square of the number of vertices in the network. Also, the calculation time increases by the cube of the number of vertices in the network. In the decomposition technique,the network is broken into a number of smaller size subnetworks for each of which shortest paths are computed. A union of the solutions provides the solution of the original network. In all of the decomposition algirithms developed up to now, boundary vertices which divide all the subnetworks have to be included in computing shortest paths for each subnetwork. In this paper, an improved algorithm is developed to reduce the number of boundary vertices to be engaged. In the algorithm, only those boundary vertices that are directly connected to the subnetwork are engaged. The algorithm is suitable for an application to real time computation using a parallel processor system which consists of a number of micro-computers or prcessors. The algorithm has been applied to a 39- vertex network and a 232-vertex network. The results show that it is efficient and has better performance than any other algorithms. A parallel processor system has been built employing an MZ-80 micro-computer and two Z-80 microprocessor kits. The former is used as a master processor and the latter as slave processors. The algorithm is embedded into the system and proven effective for real-time shortest path computations.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.4
• /
• pp.288-295
• /
• 2023

This paper deals with the dynamic simulation method for analysis of driving characteristics of aircraft and towing vehicles (TUG) on carrier vessel in wave motions. For prompt deployment in a short period of time, optimization of the movement of carrier aircraft becomes a major issue. In this regards, strategy studies using real-time simulation technology and optimal decision-making technologies are being conducted. In the present work, the dynamic characteristics of carrier aircraft and TUG connected by towbar or towbarless mechanism were investigated by means of multi-body dynamics model. Meanwhile, for real-time simulation, Dugoff's model of tire loads calculation was adopted. Through comparative analysis it was confirmed that the similarity of results between the multi-body contact model and the tire load calculation model can be achieved by coefficients tuning.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.426-439
• /
• 1996

In this paper, we propose a simple algorithm to calculate the numbers of the passing cars by using an image processing sensor for the digital black and white images with 256 tone level. Shadow is one of the most troublesome factor in image processing. By differencing the tone level, we cannot discriminate between the body of the car and its shadow. In our proposed algorithm, the area of the shadow is excluded by recognizing the position of each traffic lane. For real-time operation and simple calculation, two lines of the tone level are extracted and the existences of cars are recognized. In the experimental application on a high-way, the recognition rate of the real-time operation is more than 94%.

• Proceedings of the KOSOMBE Conference
• /
• v.1994 no.05
• /
• pp.96-99
• /
• 1994

Despite the simplicity of processing, a conventional autocorrelation function(ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In case of weak or noise corrupted Doppler ultrasound signal. the ACF method is very sensitive to the threshold level and data window length. It is very troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm was adopted to estimate the FHR. This method is more accurate, robust and reliable than the ACF method. With a lot of calculation, however, it is impossible to process real time FHR estimation. This paper is presented a new FHR estimation algorithm for real time processing.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.11 no.4
• /
• pp.251-257
• /
• 2016

The multi-core technology has become pervasive in embedded systems. An implementation of the Doppler Beam Sharpening algorithm that improves the azimuth resolution by using doppler frequency shift is possible only in multi-core environment because of the amount of calculation. In this paper, we design of multi-core architecture for a real time implementation of DBS algorithm. And based on designed structure, we produce a DBS image on P4080 board.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.63 no.4
• /
• pp.260-265
• /
• 2014

Recently, many active noise control (ANC) systems, which employ the adaptive filter controlling method, have been reported for eliminating unwanted noise. ANC systems based on the filtered-X least mean square (FXLMS) algorithm have a problem with compensating the acoustic feedback of secondary route. It is difficult to apply the real time, because transfer function of secondary route must be measured by off-line method to solve this problem. In this paper, we propose the ANC system that applies a correlation LMS(CLMS) algorithm for improving a problem of transfer function measurement. The proposed algorithm is based on input of road noise. The proposed ANC systems have an advantage of real-time process without degradation of performance, although there are many calculation compared with FXLMS algorithm.

• Transactions of Materials Processing
• /
• v.30 no.4
• /
• pp.172-178
• /
• 2021

The cold forging process induces material deformation in an enclosed space, generating a very high forging load. Therefore, it is mainly designed as a multi-stage process, and fatigue failure occurs in forging die due to cyclic load. Studies have been conducted previously to quantitatively predict the fatigue limit of cold forging dies, however, there was a limit to field application due to the large error range and the need for expert intervention. To solve this problem, we conducted a study on the introduction of a real-time forging load measurement technology and an automated system for quantitative prediction of die life cycle. As a result, it was possible to reduce the error range of the quantitative prediction of die life cycle to within ±7%, and it became possible to use the die life cycle calculation algorithm into an automated system.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.4
• /
• pp.283-289
• /
• 2018

Launch Acceptability Region(LAR) means an area for successfully hitting the target. And LAR should be calculated in real time on aircraft so that LAR can be seen by pilot. LAR can be changed by the launch condition of the bomb, the impact condition of the target, and the atmospheric condition at the time of flight of the bomb. In this paper, we propose the calculation method of LAR using Artificial Neural Network(ANN). The learning data was generated by changing each condition from existing LAR model, and LAR model was derived through ANN learning. We confirmed the accuracy of the new LAR model by comparing the difference between the result data of existing LAR model and the new LAR model. And we confirmed the possibility of real time calculation of the LAR model on the aircraft by comparing the calculation time.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.258-263
• /
• 2010

Sound localization algorithm usually adapts three step process: sampling sound signals, estimating time difference of arrival between microphones, estimate location of sound source. To apply this process in indoor environment, sound localization algorithm must be strong enough against reverberant and noisy condition. Additionally, calculation efficiency must be considered in implementing real-time sound localization system. To implement real-time robust sound localization system we adapt four low cost condenser microphones which reduce the cost and total calculation load. And to get TDOA(Time Differences of Arrival) of microphones we adapt GCC-PHAT(Generalized Cross Correlation-Phase Transform) which is robust algorithm to the reverberant and noise environment. The position of sound source was calculated by using iterative least square algorithm which produce highly accurate position data.

• Journal of Aerospace System Engineering
• /
• v.12 no.5
• /
• pp.48-53
• /
• 2018

In this study, Real-Time Operating System(RTOS) and 3-D collision avoidance algorithm are implemented to three different Miciro Controller Unit(MCU)s and their performances compared. We selected Microchip Technology's ATmega2560, STM's ARM Cortex-M3 and ARM Cortex-M4, because they are widely used. FreeRTOS, an open-source operating system, was also used. The 3D collision avoidance algorithm consists of the vertical and the horizontal avoidance algorithm, which is implemented using C++. The performances of the MCUs were compared with respect to used memory and calculation time. As a result, Cortex-M4's calculation time was the fastest and ATmega2560 used least memory.