• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.51-76
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• 2009

In this paper, a new hybrid opto-digital multiple information hiding and real-time extracting system was suggested and implemented using a volume holographic optical correlator. The multiple information hiding system in which the multiple information can be hided in an arbitrary cover image was digitally implemented by using the combination of pseudo random sequence and Hadamard matrix. In addition, a real-time optical extraction system in which the hided multiple information in a cover image can be extracted in real-time was implemented by using a volume holographic optical correlator. In the VanderLugt-type holographic optical correlator used in this experiment, the multiful matched spatial filters corresponding each of the hided informations were recorded in a photorefractive crystal by using the moving window-based angular multiplexing scheme.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1289-1293
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• 2010

A slipring or FORJ are usually adopted in order for power supply of Geo-centrifuge and input/output data acquisition. Since using slipring causes quite a lot electrical noise, an optical communication using FORJ becomes more general for data acquisition. Such data acquisition devices, however, require frequent maintenance and replacement due to deterioration by long term usage. DICT has set up a real-time wireless date acquisition system using wireless communication technology instead of FORJ. The system enables a remote measurement at any inertial acceleration field up to 100g level and provides as same performance as FORJ. The priority of this system is to use a normal modem substituting a special FORJ.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.241-248
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• 2009

This paper presents stochastic methodology based fault detection algorithm for induction motor systems. We measure current of healthy induction motors by means of hall sensor systems and then establish its probability distribution. We propose online probability density estimation which is effective in real-time implementation due to its simplicity and low computational burden. In addition, we accomplish theoretical analysis of the proposed estimation to demonstrate its convergence property by using statistical convergence and system stability theories. We apply our fault detection approach to three-phase induction motors and achieve real-time experiment for evaluating its reliability and practicability in industrial fields.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.605-613
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• 2009

In this paper, we studied for the real-time azimuthal measurement of HMD (Head Mounted Display) to control the tele-operated vision system on the mobile robot. In the preexistence tele-operated vision system, a joystick was used to control the pan-tilt unit of the remote camera system. To give the sense of presence to the tele-operator, we used a HMD to display the remote scene, measured the rotation angle of the HMD on a real time basis, and transmitted the measured rotation angles to the mobile robot controller to synchronize the pan-tilt angles of remote camera with the HMD. In this paper, we suggest an algorithm for the real-time estimation of the HMD rotation angles using feature points extraction from pc-camera image. The simple experiment is conducted to demonstrate the feasibility.

• Journal of Computing Science and Engineering
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• v.9 no.2
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• pp.108-117
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• 2015

Interrupt handling is generally separated from process scheduling. This can lead to a scheduling anomaly and priority inversion. The processor can interrupt a higher priority process that is currently executing, in order to handle a network packet reception interruption on behalf of its intended lower priority receiver process. We propose a new network interrupt handling scheme that combines interrupt handling with process scheduling and the priority of the process. The proposed scheme employs techniques to identify the intended receiver process of an incoming packet at an earlier phase. We implement a prototype system of the proposed scheme on Linux 2.6, and our experiment results show that the prototype system supports the predictable real-time behavior of higher priority processes even when excessive traffic is sent to lower priority processes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.107-112
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• 1996

In this paper it is proposed a new approach to the development of the automatic vision system to examine and repair the steam generator tubes at remote distance. In nuclear power plants workers are reluctant of works in steam generator because of the high radiation environment and limited working space. It is strongly recommended that the examination and maintenance works be done by an automatic system for the protection of the operator from the radiation exposure. Digital signal processors are used in implementing real time recognition and examination of steam generator tubes in the preposed vision system, Performance of proposed digital vision system is illustrated by experiment for similar steam generator model.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.172-176
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• 2013

This paper presents a modified filtered-x least mean square (FxLMS) algorithm to improve the stability of active noise control (ANC) system in realistic environment. A real-time ANC system employing modified FxLMS is designed and implemented on digital signal processor (DSP) board. The ANC system is evaluated for cancelling various tonal frequency noises in the range from 100 to 500 Hz and the performance is measured in terms of sound pressure level (SPL) attenuation. Experiment results show that a quiet zone with maximum 20 dB SPL attenuation can be generated around the location of error microphone.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.11
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• pp.660-668
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• 2005

Digital communication networks have become a core technology in advanced building automation systems. BACnet (Building Automation and Control networks) is a standard data communication protocol designed specifically for building automation and control systems. BACnet adopts Master-Slave/Token-Passing (MS/TP) protocol as one of its field level networks. Tn this study, we introduce a method of implementing bandwidth allocation scheme in the MS/TP protocol. The bandwidth allocation scheme improves the capability of real-time communication of the original MS/TP protocol. The bandwidth allocation scheme introduced in this paper can be easily implemented in the existing MS/TP protocol with a slight modification. In this study, we examined the validity of bandwidth allocation scheme using simulation models. The results from the simulation experiment show that the proposed scheme satisfies the requirements of real-time communication.

• Speech Sciences
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• v.3
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• pp.177-186
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• 1998

This paper describes the procedure of implementing a real-time speech codec, G.723.1 which was developed by DSP Group and standardized by ITU-T, using fixed-point DSP, ADSP-2181. This codec has two bit rates associated with it, 5.3 and 6.3 kbit/s. We implemented only one bit rate, 6.3 kbit/s, of the two with fixed-point 32-bit precision. According to the result of the experiment, the amount of computational burden is about 55 MIPS and its quality is similar to the result of the PC simulation with floating-point arithmetic. In this paper, we proposed a method to use a fixed-point DSP and a procedure for developing a real-time speech codec using DSPs and finally developed a G.723.l speech codec for ADSP-2181.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.1-8
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• 2004

A newly-built inverter has to undergo a series of stress tests in the final stage of production line. This can be achieved by connecting it to a dynamometer consisting of a three-phase machine joined by a rigid shaft to a DC load machine. The latter is controlled to create some specific load characteristic needed for the test. In this paper a test method is proposed, in which no mechanical equipment is needed. The suggested test stand consists only of a inverter to be tested and a simulator converter. Both devices are connected back-to-back on the AC-side via smoothing reactors. The simulator operates in real-time as an equivalent load circuit, so that the device under test will only notice the behaviour of a three-phase machine under consideration of the load. In oder to prove rightness of the suggested test method, the simulation and actural experiment carried out emulation for a 2.2kW induction motor.