• Imaging Science in Dentistry
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• 제40권3호
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• pp.103-107
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• 2010

Purpose : This study was performed to examine the effects of image filter on observer performance by counting the number of holes at each wedge step on a radiographic image. Materials and Methods : An aluminum step wedge with 11 steps ranged in thickness from 1.5 mm to 16.5 mm in 1.5 mm increments was fabricated for this study. Each step had 10 notched holes with 1.0 mm diameter on the bottom of the step wedge which were ranged in depths from 0.1 mm to 1.0 mm in 0.1 mm increments. Digital radiographic raw images of the aluminum step wedge were acquired by using CCD intraoral sensor. The images were processed using several types of noise reduction filters and kernel sizes. Three observers counted the number of holes which could be discriminated on each step. The data were analyzed by ANOVA. Results : The number of holes at each step was decreased as the thickness of step was increased. The number of holes at each step on the raw images was significantly higher than that on the processed images. The number of holes was different according to the types and kernel sizes of the image filters. Conclusions : The types and kernel sizes of image filters on observer performance were important, therefore, they should be standardized for commercial digital imaging systems.

• 대한영양사협회학술지
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• 제11권2호
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• pp.159-169
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• 2005

The purpose of this study was to assess the energy expenditure and investigate the relationship between related variables in 70 female university students. Resting energy expenditure estimated by Harris-Benedict formula, WHO/NAO/FAO formula and various formulas based on body weight and body surface area were 1366.9$\pm$74.4kcal/day, 1287.8$\pm$106.6kcal/day, 1171.4$\pm$155.8kcal/day and 1342.0$\pm$97.4kcal/day. Measured resting energy expenditure by indirect calorimetry(Model : Metavine and TrueOne2400) were 1582.0$\pm$150.1kcal/day and 1268.2$\pm$152.9kcal/day, respectively. Average step number per day was 11981.2$\pm$3014.4 steps and average step number per hour was 746.1$\pm$198.0 steps/hr. Daily energy expenditure by using Harris-Benedict formula, body weight formula, body surface area formula, WHO/NAO.FAO formula and 15-min check list formula were 2374.7$\pm$249.6kcal, 2033.5$\pm$313.2kcal, 2331.2$\pm$266.0kcal, 2240.8$\pm$185.5kcal and 2195.5$\pm$398.3kcal. Meanwhile energy intake of subjects was 1714.9$\pm$551.2 kcal. Daily energy expenditure has positive correlation(r=0.262) with daily step number. And there was significant positive correlations(r=0.35-0.68) between various daily energy expenditures and muscle mass. These results suggested that increase of daily step number by using pedometer is good method to increase daily energy expenditure. In particular, increase in step number can reinforce the amounts of muscle.

• 대한물리치료과학회지
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• 제16권1호
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• pp.31-39
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• 2009

Background: Community ambulation has been recently recognized as one of the most essential factors of activities of daily living in patients with post-stroke hemiparesis. This study aimed to compare walking velocity and step number in 5 community situations in patients with post-stroke hemiparesis. Methods: Ten chronic stroke patients volunteered for this study. The main variables analyzed were walking speed and step number, and these were measured in 5 different community situations: a physical therapy room, a parking lot, a bank, a crosswalk, and a hospital lobby. The measurements obtained for walking in the physical therapy room were measured using a 10m walk test and were used as baseline data for comparison with each option. The ambulation distance was set at 300m for the parking lot and the bank and 150m for the crosswalk and hospital lobby. For data analysis, walking speed and step number were standardized with the distance options of each ambulation. Results: Compared to the walking speed in the physical therapy room, those in the other situations, except for the parking lot, were significantly different (p<.05). Moreover, there were significant differences in the speeds between the bank and the parking lot and between the parking lot and the crosswalk (p<.05). Compared to the step number in the physical therapy room, those in all situations except for the crosswalk were significantly different (p<.05). Further, there was a significant difference in the step number between the bank and the crosswalk (p<.05). Conclusion: The walking ability of patients with hemiparesis in real environments within a community could be different from that in a physical therapy room. Therefore, the evaluation of walking should be performed in a variety of community situations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.635-639
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• 2003

When we carry out acoustic holography, step-by-step measurement provides us larger aperture size with same number of microphones. But when we carry out step-by-step measurement, it is blown that sound signal must be stationary. However, when transfer function between input and output signal is time-invariant, we can apply step-by-step measurement to acoustic holography even if sound signal is transient We have to do only some Processing on signals from step-by-step measurements to make the signal data of each step compatiable with other steps. This paper accounts for that processing method.

• Journal of information and communication convergence engineering
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• 제5권2호
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• pp.131-135
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• 2007

In this paper, The proposed algorithm consists of three steps. In the first step, TD(Transition Density) calculation has to be performed. a CLB-based CPLD low-power technology mapping algorithm considered a Trade-off is proposed. To perform low-power technology mapping for CPLDs, a given Boolean network has to be represented in a DAG. Total power consumption is obtained by calculating the switching activity of each node in a DAG. In the second step, the feasible clusters are generated by considering the following conditions: the number of inputs and outputs, the number of OR terms for CLB within a CPLD. The common node cluster merging method, the node separation method, and the node duplication method are used to produce the feasible clusters. In the final step, low-power technology mapping based on the CLBs packs the feasible clusters. The proposed algorithm is examined using SIS benchmarks. When the number of OR terms is five, the experiment results show that power consumption is reduced by 30.73% compared with TEMPLA, and by 17.11 % compared with PLA mapping.

• 제어로봇시스템학회논문지
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• 제16권4호
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• pp.313-318
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• 2010

This paper deals with the relationship between zeros and step response of the second and third order LTI (Linear Time Invariant) SISO (Single-Input and Single-Output) systems with complex poles. Although it has been known that the maximum number of local extrema is less than the number of zeros in the system with only real poles[8], some cases with complex poles are shown in this paper to have many local extrema. This paper proposes monotone nondecreasing conditions and describes the relationship between the transient response and the number of local extrema in step response with each region of zeros.

• Journal of information and communication convergence engineering
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• 제5권1호
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• pp.59-63
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• 2007

In this paper, a CLB-based CPLD low-power technology mapping algorithm considered a Trade-off is proposed. To perform low-power technology mapping for CPLDs, a given Boolean network has to be represented in a DAG. The proposed algorithm consists of three steps. In the first step, TD(Transition Density) calculation has to be performed. Total power consumption is obtained by calculating the switching activity of each node in a DAG. In the second step, the feasible clusters are generated by considering the following conditions: the number of inputs and outputs, the number of OR terms for CLB within a CPLD. The common node cluster merging method, the node separation method, and the node duplication method are used to produce the feasible clusters. In the final step, low-power technology mapping based on the CLBs packs the feasible clusters. The proposed algorithm is examined using SIS benchmarks. When the number of OR terms is five, the experiment results show that power consumption is reduced by 30.73% compared with TEMPLA, and by 17.11 % compared with PLA mapping.

• Structural Engineering and Mechanics
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• 제22권6호
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• pp.701-717
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• 2006

In the existing reports regarding free transverse vibrations of the Euler-Bernoulli beams, most of them studied a uniform beam carrying various concentrated elements (such as point masses, rotary inertias, linear springs, rotational springs, spring-mass systems, ${\ldots}$, etc.) or a stepped beam with one to three step changes in cross-sections but without any attachments. The purpose of this paper is to utilize the numerical assembly method (NAM) to determine the exact natural frequencies and mode shapes of the multiple-step Euler-Bernoulli beams carrying a number of lumped masses and rotary inertias. First, the coefficient matrices for an intermediate lumped mass (and rotary inertia), left-end support and right-end support of a multiple-step beam are derived. Next, the overall coefficient matrix for the whole vibrating system is obtained using the numerical assembly technique of the conventional finite element method (FEM). Finally, the exact natural frequencies and the associated mode shapes of the vibrating system are determined by equating the determinant of the last overall coefficient matrix to zero and substituting the corresponding values of integration constants into the associated eigenfunctions, respectively. The effects of distribution of lumped masses and rotary inertias on the dynamic characteristics of the multiple-step beam are also studied.

• Journal of Power Electronics
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• 제18권1호
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• pp.266-276
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• 2018

This paper presents a new step-up and step-down multi-pulse auto-transformer rectifier unit (ATRU) topology. This structure can achieve a wide range of output voltages, which solves the problem of auto-transformer output voltage being difficult to regulate. Adding middle taps to the primary winding and reasonably setting the number of auto-transformer windings, constituted two groups of three-phase output voltages with a $30^{\circ}$ phase difference. Multi-pulse output DC voltage is obtained after a three-phase output voltage across two rectifier bridges and inter-phase reactor. Thus, the output DC voltage is related to the number and configuration of the auto-transformer winding. In this paper, the relationship between the voltage ratio of the auto-transformer and the ratio of winding, input current and auto-transformer kilovoltampere rating are deduced and validated by simulations. On this basis, the output voltage range is optimized. An experiment on two different voltage ratio principle prototypes was carried out to verify the correctness of the analysis design.

• Journal of the Optical Society of Korea
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• 제15권3호
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• pp.244-251
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• 2011

We propose a new 2-step phase-shifting digital holographic optical encryption technique and analyze tolerance error for this cipher system. 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or ${\pi}$/2 in the reference beam path of the Mach-Zehnder type interferometer. Digital hologram with the encrypted information is Fourier transform hologram and is recorded on CCD camera with 256 gray-level quantized intensities. The decryption performance of binary bit data and image data is analyzed by considering error factors. One of the most important errors is quantization error in detecting the digital hologram intensity on CCD. The more the number of quantization error pixels and the variation of gray-level increase, the more the number of error bits increases for decryption. Computer experiments show the results to be carried out encryption and decryption with the proposed method and the graph to analyze the tolerance of the quantization error in the system.