• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.629-632
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• 1989

The scattered light intensity from a spherical particle passing through the cross-over region of two coherent laser beams, varies periodically. Photodetection of this light beams produces a periodic signal of varying amplitude. The phase of the signal varies with the particle size and refractive index, the beam crossing angle and wavelength, and the position and size of the scattered ligth collecting aperture. In this paper the phase variation with respect to the particle absorptive index of retraction, collecting lens size and beam crossing angle is calculated using both Mie scattering theory and reflection theory. The two theories show good agreement in phase predictions, especially for large absorptive indices and for small collection lenses. Both theories predict phase to be inversely proportional to the beam crossing angle.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.75-77
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• 2005

When measuring impedance of electronic component and so on, even the small size can reject the interference to shielding object. But, the interference through human body is grown when measuring bioimpedance without establishing shield specially. Consequently, when measuring bioimpedance in this paper, it proposed impedance measurement method to take advantage of spread spectrum technology, so that can reject the interference without establishing shield specially. Spread spectrum impedance measurement method to propose in this paper can reject the interference signal that occurring from medical instruments in the human body, the interference signal that is flowed in from surrounding environment when measuring impedance. It improved SJR(signal to jamming ratio) about 22dB than conventional method that actually realize and experiment spread spectrum impedance measurement method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.76-82
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• 1999

This study was carried out to verify finding performance of dental diamond bur and investigate the possibility of AE application in density field. Work pieces were made of acryl and bovine respectively for the experiments in this study. Grinding test was conducted to get the data of grinding resistance and specific finding energy of low different types of diamond bur by using tool dynamometer. AE signal was acquired to verify grinding process in the AE measuring system. AErms value was increased as the grinding velocity and depth were increasing, but it decreased as the feed rate was increasing. The case of the small value of AE signal is due to abnormal grinding in D type diamond bur. By analyzing AErms start and finish time of grinding working, abnormal grinding state can be confined. Abnormal state can be found through the behavior of AE signal in the finding working. As a result, it is expected that forecast of abnormal state is possible using AE equipments under real time process.

• Journal of Sensor Science and Technology
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• v.20 no.3
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• pp.162-167
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• 2011

In this paper, we propose a vision system using a field programmable gate array(FPGA) and a smart vision chip. The output of the vision chip is varied by illumination conditions. This chip is suitable as a surveillance system in a dynamic environment. However, because the output swing of a smart vision chip is too small to definitely confirm the warning signal with the FPGA, a modification was needed for a reliable signal. The proposed system is based on a transmission control protocol/internet protocol(TCP/IP) that enables monitoring from a remote place. The warning signal indicates that some objects are too near.

• Journal of Korean Society of Transportation
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• v.5 no.1
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• pp.3-23
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• 1987

Traffic signal control problems in urban street networks are formulated in two ways. In the formulations network flows are assumed to satisfy the user route choice criterion. the first formulation which is called implicit substiuation incorporates user route behavior implicitly in the objective function by recognizing the dependence of the link flows on the signal variables. On the other hands, the second one which is called 'penalty formulation' consists in expressing the route choice conditions in the form of a single nonlinear constraint. Approximate solution algorithm for each of the formulations was investigated in detail and computer codes were written to examine key aspects of each algorithm. A test was done on a network which is small in size but sufficiently complex in representing real-world traffic conditions and the test result shows that both algorithms produce converged solutions. It is recommended, however, that further studies should be done in order to compare the performance of each algorithm more in depth.

• International journal of advanced smart convergence
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• v.7 no.2
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• pp.33-37
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• 2018

In this study, we propose an iterative clustering algorithm that automatically clusters a set of voice signal data without a label into an optimal number of clusters and generates hmm model for each cluster. In the clustering process, the likelihood calculations of the clusters are performed using iterative hmm learning and testing while varying the number of clusters for given data, and the maximum likelihood estimation method is used to determine the optimal number of clusters. We tested the effectiveness of this clustering algorithm on a small-vocabulary digit clustering task by mapping the unsupervised decoded output of the optimal cluster to the ground-truth transcription, we found out that they were highly correlated.

• 한국컴퓨터산업교육학회:학술대회논문집
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• 2003.11a
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• pp.99-102
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• 2003

Data acquisition of biomedical signal is important that can convert health of human body to measurable datas. In this paper, we developed system that can send multiple ECG data, ECG signal in biomedical signals, using Bluetooth wireless transmission. Developed system has several features, total gain of 1000, filtering data for noise reduction in hardware / software parts, portable to carry cause it has small size and battery operation. And system was designed which can measures data in several OS(Windows 2000, Windows CE).

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.87-96
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• 1997

A pixel profile in the conventional DANTE sequence is so poor that the excited area by DANTE sequence is a small portion of a pixel. This causes poor signal to noise ratio in DANTE image. In this paper, a frequency modulated(FM) DANTE imaging sequence is proposed to improve pixel profile in DANTE image. A DANTE pulse train is shaped by an FM function so that all the spins within a pixel are excited, thereby improving the signal to noise ratio. It also shows that the pixel profiles are dependent on the sweep in FM signal. Computer simulations and experimental result obtained using a 7.0 T NMR imaging system are presented.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.176-181
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• 2001

As the data rate between chip-to-chip gets high, the skin effect and load of pins deteriorate noise margin. With these, noise disturbances on the bus channel make it difficult for receiver circuits to read the data signal. This paper has proposed a new pre-emphasis driver circuit which achieves wide noise margin by enlarging the signal voltage range during data transition. When data is transferred from a memory chip to a controller, the output boltage of the driver circuit reaches the final values through the intermediate voltage level. The proposed driver supplies more currents applicable to a packet-based memory system, because it needs no additional control signal and realizes very small area. The circuit has been designed in a 0.18 ${\mu}m$ CMOS process, and HSPICE simulation results have shown that the data rate of 1.32 Gbps be achieved. Due to its result, the proposed driver can achieved higher speed than conventional driver by 10%.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.361-367
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• 2004

This paper describes design of an algorithm for analyzing human activity using body-fixed 3-axis accelerometer in the small of the back. In the first step, we distinguish static and dynamic activity period using AC signal analysis. Then five postures were classified by applying the threshold in DC signal corresponding to the static activity period. Also, after comparison of average power and taking negative peak signal in the dynamic activity period, the four dynamic activities were classified by adaptive threshold method. To evaluate the performance of the proposed algorithm, the measured signals obtained from six subjects were applied to the proposed algorithm and the results were compared with the simultaneously measured video data. As a result, the activity classification rate of 95.7％ on average was obtained. Overall results show that the proposed classification algorithm has a possibility to be used to analyze the static and dynamic physical activity.