• Journal of Digital Convergence
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• v.17 no.10
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• pp.243-249
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• 2019

In this paper, we have developed a device to reduce the standby power consumption that is unnecessarily consumed in unused electrical appliances. The Doppler sensor is used to automatically power off and power off the outlet depending on whether or not a person is present near the outlet. The Doppler sensor uses a coaxial cable trap to design a transmitting antenna and emits a 10 GHz band RF signal and receives a reflected wave signal whose wavelength is reflected from the target object to the receiver to detect an object and recognize human approach. It automatically cuts off and restores standby power to prevent unnecessary power consumption, saving energy and developing a standby power automatic shutdown and recovery device that can prevent the risk of large fires caused by leakage current.

• The Journal of Information Technology
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• v.4 no.2
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• pp.129-136
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• 2001

Most of the acoustic microscopes have been constructed acoustic image by simply measuring the amplitude of the reflected signal from the specimen. This method fails to produce images of good quality because the change in amplitude is not sensitive enough to specimen with fine variation. In this paper, we have been constructed the acoustic microscope system which has been able to measure simultaneously the amplitude and phase of the reflected ultrasonic signal. And also we have been constructed the amplitude and phase images for the 500 won coin as a sample and the alumium spacimen with internal round defect, and compared and analyzed these images. In expermental result, the phase image have shown better sensitive than the amplitude image and given better contrast for the micro height variation of specimen. It will be expected that the phase image can be used as an additional bit of information to improve ambiguituities in amplitude image on nondestructive testing for specimen with fine variation.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.48-54
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• 2013

With the development of IT convergence technology and the construction of infrastructure for water leakage detection, the detection technology of damaged pileline's location and size is being spotlighted. The exhaustion of water resource due to the leakage of water supply facilities renders it urgent to detect water leakage effectively. In this paper, we proposed the water leakage detection monitoring simulation using the power spectrum analysis. We measured the reflected wave signal by the proposed water leakage detection monitoring simulation. The rate variability is calculated form the acquired reflected wave signal. And the power spectrum analysis using the Fast Fourier Transform is evaluated the correlation between the water leakage's size and the reflected wave. Ultimately, this paper suggests empirical simulation to verify the adequacy and the validity. Accordingly, the satisfaction and the quality of services will be improved the efficient management by supporting the real-time water leakage detection.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.93-103
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• 2001

A reflection signal in an active sonar using a high frequency is mainly formed of a specular reflection from the surface of an object along with several equivalent scatters inside, which are characterized by the spatial distribution of the highlight on the object. This study analyze the existing echo signal synthesis models eq, random distribution model, equivalent interval distribution model & MUTAHID(Modified Underwater TArget by HIlight Distribution) model for simulated target, and compare the characteristics of the reflected signal synthesis results for each model in various conditions. These highlight distribution models can be efficiently applied to the simulated target signals synthesis of various real systems requiring the echo signal synthesis on the underwater target.

• Journal of Ocean Engineering and Technology
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• v.28 no.1
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• pp.55-63
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• 2014

In this paper, we propose an threshold-based Schur algorithm for estimating the media characteristics of sub-bottom multi-layers by using the signal generated by a parametric array transducer. We use the KZK model to generate a parametric array signal, and use the proposed threshold-based Schur algorithm for estimating the reflection coefficients of multiple sea bottom layers. Using computer simulation, we verify that the difference frequency component generated by the KZK model prevails over the signals of primary frequencies at long range. For the simulation, we use the transmit signal generated by the KZK and the reflected signal obtained from a lattice filter model for the seawater and sub-bottom of multi-level non-homogeneous layers. Through the simulation, we verify that the proposed threshold-based Schur algorithm can give much more accurate and efficient estimates of the reflection coefficients than methods using received signal, matched filter output signal, and normal Schur algorithm output.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1803-1804
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• 2006

The purpose of this paper is to implement a Labview based TFDR Real Time system through the instruments of Pci eXtensions for Instrumentation(PXI). The proposed load impedance measurement algorithm was verified by experiments via the implemented real time system. The TFDR real time system consisted of the reference signal design, signal generation, signal acquisition, algorithm execution and results display parts. To implement real time system, all of the parts wore programmed by the Labview which is one of graphical programming languages. In the application software implemented by the Labview we were able to design a suitable reference signal according to the length and frequency attenuation characteristics of the target cable and controled the arbitrary waveform generator(ZT500PXI) of the signal generation part and the digital storage oscilloscope(ZT430PXI) of the signal acquisition part. By using the TFDR real time system with the terminal resistor on the target cable, we applied to the load impedance measurements. In the proposed load impedance algorithm a normalized time-frequency cross correlation function and a cross time-frequency distribution function was employed to calculate the reflection coefficient and phase difference between the input and the reflected signals.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2006.06a
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• pp.97-100
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• 2006

A sensor and measuring system were implemented to measure both uroflow and urophonography signal during urination for diagnose the BPH(benign prostatic hypertrophy). The implemented system was composed of the uroflow sensor using the load-cell, the urophonography measurement sensor so as stethoscope type, pre-processing part for sensors signal detection, amplifier and filter, system control parts and PC measurement program. A simulator of the lower urinary system that is experimental equipment implemented for evaluates the developed system. The two signals were measured using implemented system and analyzed these signal by means of time domain and frequency domain for extraction of the characteristic parameter which can most effectively reflected by the occlusion of the lower urinary system. Furthermore two signals were measured and analyzed with the subject of 5 healthy adult for clinical application possibility of the implemented system. As a result, the most influence bandwidth of effect according to occlusion of the lower urinary system is $253{\sim}282Hz$ of the urophonography signal.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1824-1827
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• 1998

A Laser Doppler Vibrometer(LDV) was developed using He-Ne laser as a light source. The heterodyne method was employed and its output signal was digitally processed with a $\mu$-processor and the result was displayed with LCD. The frequency shifted object beam(40 MHz) by a Bragg cell was focused on the surface of the moving target and the Doppler shifted reflected beam was recombined with reference beam at the fast photodetector to produce frequency modulated signal centered at 40 MHz. The signal from the detector was amplified and downconverted to intermediate frequency centered at 1 MHz after mixing process. The voltage output that was proportional to the velocity of the moving surface was obtained using PLL. With the same method, the fringe pattern signal of the moving surface is obtained. This fringe pattern signal is converted to TTL signal with ZCD(zero-crossing detector) and then counted to calculate the displacement due to the vibration, which is displayed with LCD. This LDV can be used to measure the resonant frequency of the electric equipments such as circuit breakers and transformers, of which resonant frequencies are changed when they are damaged.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.189-194
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• 2006

Dam jerk causes a chronic stomach disorder. The number of the patient of the Dam jerk increase in these days. However, there are no objective and quantitative study for a diagnosis of Dam jerk. Therefore, we designed diagnosis system using ultrasonic response signal for a diagnosis of Dam jerk. It was used to collect the response signal that is reflected at Dam jerk region of the abdominal. And then, the response signal at the Dam jerk region is 20% higher than the normal region. In the result. we could prove the reliability of the system.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.91-95
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• 1984

Because of layer and scattering in the ocean, there are some problem in algorithm currently used for the recognition of targets. Those are time delay of processing and circuit design. The simple method of detecting direct sound wave in noise caused by time delay is proposed-recognized, estimated, and then direcxt sound wave is reconstructed by the AMDF and $\mu$-processor. 2KHz, 4KHz, 8KHz, 12KHz, 16KHz sound waves are used in experiment. To obtain a reference signal, anechoic water tank is used is processing and aluminium water tank used instead of real ocean. As a result, there are a few errors which caused by anechoic water tank error, decreasing of frequency make errors. Possibility of application to Sonar Signal Processing is proved.