• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.264-271
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• 2011

ILS(Instrument Landing System) is the international standard system for approach and landing guidance. ILS was adopted by ICAO(International Civil Aviation Organization) in 1947 and is currently being used in commercial systems. To design the digital transmitter and receiver modules that can be mounted in the integrated ILS, we propose the digital design methods of digital double AM modulator and demodulator using FPGA chip, DDS(Direct Digital Synthesizer) for generation of sampling clock, demodulator of DDC(Digital Down Converter) structure, and spectrum analyzer using DSP chip. We demonstrate the efficiency of the proposed design method through experiments using developed transmitter and receiver modules. This system can be used as a high-performance commercial system.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.98-100
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• 2007

This paper proposes a robust digital controller for PWM voltage source inverter using CRA method. The usual inverter controller for the operation of constant voltage and constant frequency consists of a double looped PI controller for the outer voltage controller and the inner current controller, of which the order of characteristic polynomial is high and so the gain tuning is difficult. Considering the limited switching frequency of the devices and sampling frequency of the digital controller, the gain tuning is usually based on the engineering experiences with the try and error method. In this paper, the error-space approach is used to get the system model including the controller with low order, and the characteristic ratio assignment (CRA) method is proposed for the design of robust controller which has the advantage to design the optimal gain to meet the referenced response and overshoot within the limit range. The PSiM simulation and experience results are shown to verify the validity of the proposed controller.

• Journal of Power Electronics
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• v.15 no.2
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• pp.411-418
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• 2015

In this paper, a new method for the online estimation of equivalent series resistances (ESR) of the DC-link capacitors in induction machine (IM) drive systems with a front-end diode rectifier is proposed, where the ESR estimation is conducted during the regenerative operating mode of the induction machine. In the first place, a regulated AC current component is injected into the q-axis current component of the induction machine, which induces the current and voltage ripple components in the DC-link. By processing these AC signals through digital filters, the ESR can be estimated by a recursive least squares (RLS) algorithm. To acquire the AC voltage across the ESR, the DC-link voltage needs to be measured at a double sampling frequency. In addition, the ESR current is simply reconstructed from the stator currents and switching states of the inverter. Experimental results have shown that the estimation error of the ESR is about 1.2%, which is quite acceptable for condition monitoring of the capacitor.

• Women's Health Nursing
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• v.16 no.2
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• pp.116-125
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• 2010

Purpose: The purpose of this study was to investigate the relationship between health locus of control, exercise self-efficacy and exercise benefits / barriers of female college students. Methods: Convenient sampling was used to recruit participants from a University based in Pusan. Data were collected from October 15 to December 20, 2007, and participants were 322 students. The questionnaires administered consisted of Multidimensional Health Locus of Control (HLOC) Scales, Exercise Self-efficacy Scale, and Exercise Benefits / Barriers Scale. Descriptive statistics, ANOVA, and Pearson's correlation coefficients were used to analyze the data. Results: The mean scores for the HLOC among female students was HLOC-I: 22.24, HLOC-P: 16.82, HLOC-C: 15.16. The mean scores were exercise self-efficacy: 37.45, exercise benefit: 2.96, and exercise barriers: 2.89. The 'double external' response pattern of HLOC was the largest group in female students with significant difference in exercise benefit between response patterns of HLOC. There were significant correlations between HLOC-I, exercise self-efficacy, and exercise benefit/barriers. Conclusion: The results of this study suggest that tailored health management program by pattern of HLOC should be developed to promote the exercise behavior and enhance the exercise self-efficacy and benefit for female students.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.763-771
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• 2011

Development and distribution of Japanese mantis shrimp, Oratosquilla oratoria (De Haan) larvae were investigated in the northwestern water off Incheon. O. oratoria larvae were monthly collected at 15 stations from early June to early October in 2007. Bongo net with 330 and 505 um mesh was deployed in a double once with an oblique tow way. Larval densities were relatively higher in southerner stations in July and in northerner stations in August and September. No larvae were discovered in June. Zoea I and II were not captured during the entire sampling period. Zoea III occurred in July for the first time and were found until September. Thereafter, the proportion of later stages increased. The number of zoeal stages decreased during the summer months and no larvae were found in October. Of zoeal stages, zoea IV was the most abundant in number. Zoeal densities were highest in July and August, particularly at the stations near the coast. O. oratoria larvae may be retained and grow within our study sites without advection to growing areas. Non-occurrence of zoea I and II indicate that they were retained near spawning grounds or near parental burrows. Pattern of larval occurrence was coincided with previous researches conducted in conspecific distribution ranges.

• Journal of Sensor Science and Technology
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• v.27 no.6
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• pp.362-367
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• 2018

A complementary metal oxide semiconductor (CMOS) binary image sensor is proposed for low-power and low-noise operation. The proposed binary image sensor has the advantages of reduced power consumption and fixed pattern noise (FPN). A gate/body-tied (GBT) p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET)-type photodetector is used as the proposed CMOS binary image sensor. The GBT PMOSFET-type photodetector has a floating gate that amplifies the photocurrent generated by incident light. Therefore, the sensitivity of the GBT PMOSFET-type photodetector is higher than that of other photodetectors. The proposed CMOS binary image sensor consists of a pixel array with $394(H){\times}250(V)$ pixels, scanners, bias circuits, and column parallel readout circuits for binary image processing. The proposed CMOS binary image sensor was analyzed by simulation. Using the dynamic comparator, a power consumption reduction of approximately 99.7% was achieved, and this performance was verified by the simulation by comparing the results with those of a two-stage comparator. Also, it was confirmed using simulation that the FPN of the proposed CMOS binary image sensor was successfully reduced by use of the double sampling process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.517-532
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• 2021

Safe geological disposal of spent nuclear fuel (SNF) requires knowledge of the deep hydrochemical characteristics of the repository site. Here, we conducted a set of deep hydrochemical investigations using a 750-m borehole drilled in a model granite system in Wonju, South Korea. A closed investigation system consisting of a double-packer, Waterra pump, flow cell, and water-quality measurement unit was used for in situ water quality measurements and subsequent groundwater sampling. We managed the drilling water labeled with a fluorescein dye using a recycling system that reuses the water discharged from the borehole. We selected the test depths based on the dye concentrations, outflow water quality parameters, borehole logging, and visual inspection of the rock cores. The groundwater pumped up to the surface flowed into the flow cell, where the in situ water quality parameters were measured, and it was then collected for further laboratory measurements. Atmospheric contact was minimized during the entire process. Before hydrochemical measurements and sample collection, pumping was performed to purge the remnant drilling water. This study on a model borehole can serve as a reference for the future development of deep hydrochemical investigation procedures and techniques for siting processes of SNF repositories.

• Child Health Nursing Research
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• v.29 no.1
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• pp.72-83
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• 2023

Purpose: North Korean refugee women struggle with the double burden of adaptation and parenting as mothers in a new environment. This study aimed to identify the knowledge, confidence, and educational needs regarding newborn care among North Korean refugees, and to determine differences between these variables according to participants' characteristics. Methods: Data were collected from September to October 2022, and 150 North Korean refugee women recruited using convenience sampling participated in the study. Descriptive statistics, the t-test, analysis of variance, and Pearson correlation analysis were used for data analysis. Results: The mean scores were as follows: parenting knowledge, 14.97 out of 25; infection prevention knowledge and confidence, 20.09 out of 33 and 51.37 out of 80, respectively; and educational needs, 245.86 out of 310. Significant differences were observed in newborn care, knowledge, and confidence according to maternal age, educational level, family structure, and pregnancy history. Significant positive correlations were observed between the participants' newborn care knowledge, confidence, and educational needs. Conclusion: Personalized educational programs should be implemented to enhance North Korean refugee women's confidence in newborn care, focusing on areas with low knowledge levels and high educational needs and enabling women to achieve healthy pregnancy and childbirth, and to parent well.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.118-126
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• 2022

This study attempts a comparison between AHP(Analytic Hierarchy Process) in which the importance weight is structured by individual subjective values and regression model with importance weight based on statistical theory in determining the importance weight of casual model. The casual model is designed by for students' satisfaction with university, and SERVQUAL modeling methodology is applied to derive factors affecting students' satisfaction with university. By comparison of importance weights for regression model and AHP, the following characteristics are observed. 1) the lower the degree of satisfaction of the factor, the higher the importance weight of AHP, 2) the importance weight of AHP has tendency to decrease as the standard deviation(or p-value) increases. degree of decreases. the second sampling is conducted to double-check the above observations. This study empirically checks that the importance weight of AHP has a relationship with the mean and standard deviation(or p-value) of independence variables, but can not reveal how exactly the relationship is. Further research is needed to clarify the relationship with long-term perspective.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.82-93
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• 2023

The purpose of this study is to investigate the effect of female college students' participation in dance sports on their perception of body attractiveness and their desire for exercise. In order to achieve the purpose of this study, female college students residing in Gwangju Metropolitan City and Jeonnam in 2022 were selected as the population, and a total of 390 students were selected as study subjects using cluster random sampling. A total of 300 participants, 170 participants in dance sports and 130 non-participants, were selected as study subjects, excluding 90 copies of double entry and insincere data. As a survey tool, the questionnaire whose reliability and validity had already been verified in previous domestic and foreign studies was modified and supplemented to suit the purpose of this study. The collected data were computerized according to the purpose of analysis using SPSS Windows 20.0 Version, a statistical program. The results obtained through this procedure are as follows. First, there were partial differences in physical evaluation according to demographic characteristics. Second, there was a partial difference in exercise desire according to demographic characteristics. Third, physical evaluation was found to partially affect exercise desire.