• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.95-102
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• 2014

This paper presents zero crossing point(ZCP) estimation methods considering discretization error for a high speed brushless DC(BLDC) motor drive. The ZCP is estimated by detecting the change of back-EMF polarity for the BLDC sensorless drive, and the discretization error exist on the estimated ZCP. The discretization error of the ZCP is a cause of the delay of a commutation timing of current and increment of a current ripple factor. Besides a delay of a ZCP estimation brings on the limitation of a speed range for the BLDC sensorless drive. The compensation method based on the error analysis with probability theory for reducing the effects of the discretization error of the ZCP is proposed. Also a ZCP estimation method according to the Back-EMF patterns is proposed to widen the speed range for the BLDC sensorless drive. The proposed methods are verified by the experiment.

• Computers and Concrete
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• v.14 no.2
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• pp.145-161
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• 2014

The article presents the statistical method of grouping the results of the compressive strength of concrete in continuous production. It describes the method of dividing the series of compressive strength results into batches of statistically stable strength parameters at specific time intervals, based on the standardized concept of "concrete family". The article presents the examples of calculations made for two series of concrete strength results, from which sets of decreased strength parameters were separated. When assessing the quality of concrete elements and concrete road surfaces, the principal issue is the control of the compressive strength parameters of concrete. Large quantities of concrete mix manufactured in a continuous way should be subject to continuous control. Standardized approach to assessing the concrete strength proves to be insufficient because it does not allow for the detection of subsets of the decreased strength results, which in turn makes it impossible to make adjustments to the concrete manufacturing process and to identify particular product or area on site with decreased concrete strength. In this article two independent methods of grouping the test results of concrete with statistically stable strength parameters were proposed, involving verification of statistical hypothesis based on statistical tests: Student's t-test and Mann - Whitney - U test.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.1
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• pp.1-7
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• 2010

Detecting data races is important for debugging programs with OpenMP directives, because races result in unintended non-deterministic executions of the program. It is especially important to detect the first data races to occur for effective debugging, because the removal of such races may make other affected races disappear or appear. The previous tools for race detecting can not guarantee that detected races are the first races to occur. This paper suggests a tool what detects the first races to occur on the program with nested parallelism using the two-pass on-the-fly technique. To show functionality of this tool, we empirically compare with the previous tools using a set of the synthetic programs with OpenMP directives.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.379-382
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• 1997

A method for measuring optical properties of biological medium was investigated by using the frequency domain spectroscopy. When amplitude-modulated light with the frequency of several tens up to several hundred MHz propagates through a scattering medium, the phase lag and the amplitude reduction occur. The phase lag depends on the average of optical path lengths. The amplitude reduction with respect to the radial distance is influenced by the penetration depth. The mean of optical path length and penetration depth are related to optical coefficients. The phase lag and the amplitude reduction were measured based on the heterodyne detection method. The experimental data were fitted with the theoretical curves derived from diffusion theory and the absorption and scattering coefficients were calculated.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1087-1094
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• 2004

Normally, formalization and standardization are followed while doing any system analysis and design. But, in actual system development, products can't be written using the automated tool for all products due to their own characteristics. That results the inconsistency among development products and various kinds of problem can occur in the products. In this paper, we present a technique that supports consistency among products of analysis and design phase developed according to object oriented method. And, this paper also presents the implementation tool.

• 전기의세계
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• v.22 no.1
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• pp.35-41
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• 1973

An automatic point traffic control method is recommended for more idealistic traffic flow over coarse road netowrks. The automatic control apparatus recommended, consists of a transceiver, amplifier, digital-to-analog converter, signal light controller for emergency and steady state, and digital counter as monitor. The transmitter sends a signal to the target vy means of Microwave-FM-CW and a diode detector picks up the echo signal. Thus the operation of the entire system will be carried out through an open loop state. Some factors necessary for an ideal detector system are rapid response, longevity and stability. An analytical method of the Doppler effect substitutes the conventional frequency deviation into the amplitude of detector output. The changing rate of amplitude is proportional to the voltage of the detector output. Some induced formula from Maxwell's radiation field theory ensures this new method, and, new method, and proves the fact with an experimental data presentation. Stability depends upon Klystron as an oscillator and a diode as a detector. the transceiver installation affects on the response and sensitivity of the system. In accordance with the detector output, several targets are easily classified by amplitudes on the scope. The traffic flow, i.e., target movement which is analyzed by the amplitude method, is shown through the scope and indicates it on the digital counter. The best efficiency for the amplitude analysis can be attained through use of an antenna having the highest sensitivity.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.1-12
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• 2003

Instead of sensory evaluation, we designed an evaluation method of the setting function of hairstyling products, based on an original theory focusing on changes in bending stress observed when a load with continuous bending is applied to human hair. Specifically, we developed a device to measure bending stress to quickly and objectively evaluate the condition of human hair, particularly its dynamic properties such as the setting function, following the application of hairstyling products. This device generates a load with continuous bending while applying a pendulum motion to a hair tress, one end of which is anchored. The setting function and holding power of resins of various molecular weight and ionic properties were evaluated using this device. The results demonstrated a close correlation with those obtained by experts' sensory evaluation. The evaluation results of bending stress and holding rate confirmed that the combined use of two different resins could improve the function of setting preparations. Evaluation using this device was able to substitute for sensory evaluation, and offers quick objective evaluation and detection of changes in the holding power of hairstyling products over time. We conclude that evaluation using this device is a promising new method.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.357-363
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• 1999

A frequency domain spectroscopic system was constructed to investigate the optical properties of multiple scattering media. The alternating current (AC) and phase lag components of backscattered light were measured by using the heterodyne detection method. Absorption and transport scattering coefficients were computed from the values based on diffusion theory. Predictions showed excellent matches in comparison with actual values of absorption and scattering. Predictable ranges of the optical coefficients were analyzed in terms of the distance between light source and detector, and modulation frequencies. A proposed compact experimental set-up using laser diodes can be utilized to estimate non-invasively the optical properties of multiple scattering media such as biological tissues.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.5
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• pp.29-36
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• 2002

In the maintenance and retrofit planning of a bridge system, the optimal strategy for inspection and repair are suggested by minimizing the expected total life-cycle cost, which includes the initial cost, the costs of inspection, repair, and failure. Degradation of seismic performance is modeled by using a damage function. And failure probability is computed according to the degree of damage detection by random vibration theory and the event tree analysis. As an example to illustrate the proposed approach, a 10-span continuous bridge structure is used. The numerical results show that the optimum number of the inspection and the repair are increased, as the seismic intensity is increased and the soil condition of a site becomes more flexible.

• Research in Community and Public Health Nursing
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• v.30 no.4
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• pp.471-483
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• 2019

Purpose: The purpose of this study was to identify factors associated with the intention of the prostate cancer screening (PCS). To achieve this purpose, a structural equation model was established based on the health belief model and the theory of planned behavior. Methods: The subjects of this study were 260 male participants who were between 40 and 74 years old and had not taken the PCS. Data were collected using a structured self-report questionnaire (i.e., perceived benefits, perceived barriers, attitude, subjective norms, perceived behavior control, and intention of the PCS). Descriptive statistics, reliability analysis, correlation analysis, confirmatory factor analysis, and fitness test were used to test hypotheses. Results: The intention of the PCS was directly affected by the perceived behavior control and indirectly influenced by the perceived benefits. The structural equation model also showed that the perceived behavior control explained 78% of the intention. Conclusion: To raise the intention to take the PCS, it is necessary to increase the confidence of a subject that may control its difficulties and inform the perceived benefits of the PCS to a subject.