• Journal of the Korean Ceramic Society
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• v.25 no.2
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• pp.125-130
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• 1988

The characteristics of the PZT/PMM and PZT/Butadiene composites with 3 dimensional network structure have been investigated as a function of the PZT volume fraction. The dielectric constants of the PZT composites increased linearly as the PZT volume fraction increased. However, they are not significantly affected by the polymer compliance. The piezoelectric d33 coefficients of the PZT/Butadiene are largest than the PZT/PMM because of the high elastic compliance which promotes stress transfer. The values of the mechanical quality factor adn frequency factor of the PZT/PMM composite are slightly larger, while the planar coupling factor is smaller, than the PZT/Butadiene composite. These results are due to strong interaction and mechanical coupling between PZT and PMM.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.408-414
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• 2005

The VCDRO(Voltage Controlled Dielectric Resonate. Oscillator) with low phase noise is designed using nonlinear analysis, and its phase noise characteristics are compared with that of Lesson's equation. The microstripline coupled with dielectric resonator is realized as a high impedance inverter to improve the phase noise performance, and the quality factor of resonator circuit can be transferred to active device with the enhanced the loaded quality factor. The worst case and part stress analyses are achieved to obtain the high reliability of VCDRO and the reliability analysis is accomplished to estimate the probability of operation at the end of life. The developed VCDRO has the oscillating tuning factor of 0.56MHZ1V for the control voltage range of 0-l2V. This VCDRO requires the DC power of 136mW. The phase noise characteristics exhibit good performances of -94.18dBc/Hz (a)10KHz and -116.3dBc/Hz (a)100KHz. And, the output power over 7.33dBm is measured.

• Ocean and Polar Research
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• v.29 no.4
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• pp.349-366
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• 2007

Seasonal variations of various physicochemical components (temperature, salinity, pH, DO, COD, DOC, nutrients-silicate, DIN, DIP) and potential limiting factor for phytoplankton primary production were studied in the surface water of semi-enclosed Masan Bay. Seasonal variations of nutrient concentrations, with lower values in summer and winter, and higher in fall, are probably controlled by freshwater loadings to the bay, benthic flux and magnitude of occurrence of phytoplankton communities. Their spatial distributional patterns are primarily dependent on physical mixing process between freshwater and coastal seawater, which result in a decreasing spatial gradient from inner to outer part of the bay. In the fall season of strong wave action, the major part of nutrient inputs (silicate, ammonium, dissolved inorganic phosphorus) comes from regeneration (benthic flux) at sediment-water interface. During the summer period, high Si:DIN and Si:DIP and low DIN:DIP relative to Redfield ratios suggest a N- and secondarily P-deficiency. During other seasons, however, silicate is the potential limiting factor for primary production, although the Si-deficiency is less pronounced in the outer region of the bay. Indeed, phytoplankton communities in Masan Bay are largely affected by the seasonal variability of limiting nutrients. On the other hand, the severe depletion of DIN (relatively higher silicate level) during summer with high freshwater discharge probably can be explained by N-uptake of temporary nanoflagellate blooms, which responds rapidly to pulsed nutrient loading events. In Masan Bay, this rapid nutrient consumption is considerably important as it can modify the phytoplankton community structures.

• International Journal of Quality Innovation
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• v.8 no.3
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• pp.156-172
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• 2007

The high-tech industry is the economic lifeline for Taiwan. Its characteristics are short product life cycle, rapid changes in the market, and a high obsolescence rate for new products. Under globalization, the high-tech industry has adopted Information Technology (IT) to shorten the manufacturing process, reduce costs and conduct product research and development (R&D) to increase the core competence of enterprises and achieve the goal of sustainable operations. Enterprises should actively strengthen their integration with internal and external resources and lead in R&D management to increase industrial operating performance. Effectively managing operations and R&D management evaluation in Taiwan's High-tech Industry has become a critical subject. This study adopted 4 major Balanced Scorecard (BSC) perspectives to establish the Total Performance Evaluation Indicators for the R&D management department in Taiwan's High-tech Industry. The Analytic Network Process (ANP) was applied to evaluate the overall performance of the R&D management department. The research framework is divided into 2 phases. The first phase is combined with the 4 major perspectives, Financial, Customer, Internal Business Process and Learning and Growth, as the related indicators for each measurement perspective. The Key Performance Indicators (KPI) were selected using Factor Analysis to identify the key factor from the complicated indicators. The relationship between the characteristics of each BSC's evaluation perspective is dependence and feedback. This study applied ANP to conduct the calculation and adjustment of correlation between each KPI, and determine on their relative weights for the objective KPI. The "Financial Perspective" for R&D management department in Taiwan's High-tech Industry focused on the budget achievement rate of R&D management. The weight indicator value is (0.05863). The "Customer Perspective" focused on problem-solving satisfaction. The weight value of this indicator is (0.17549). The "Internal Business Process Perspective" focused on the quantity and quality of R&D. The weight value of this indicator is (0.13506). The "Learning and Growth Perspective" focused on improving competence in the research personnel's professional techniques. The weight value of this indicator is (0.02789). From the total weighting indicators, the order of the Performance Indicators for the R&D management department in Taiwan's High-tech Industry is: (1) Customer Perspective; (2) Internal Business Process Perspective; (3) Financial Perspective; and (4) Learning and Growth Perspective.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.202-207
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• 2006

This study was to find out users' satisfaction on the dormitory high school in Jeonju City and to propose it's physical environmental improvement directions. This was performed by a questionnaire survey method, and the questionnaire was designed by researchers considering relative literatures. Data were collected from 200 students, who had been dwelling 4 high school dormitories in Jeonju City. By analyzing those data, findings were as follows : 1) Users of students were satisfied the whole of their dormitory; facilities, spaces, and living. 2) They were highly concerned about a library and a personal unit space in their dormitory. 3) They needed their personal unit space to be designed bedroom+bathroom type with 2 persons' sharing and be equipped one story bed and desk furniture. Also, they needed improvement on heating & cooling, small space and indoor air quality of unit space. 4) The users' satisfaction on unit space were 3.23, and the space utility and the space size of functional factor and the heating/ventilation of technical factor were highly effected their satisfaction.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.51-58
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• 2010

Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. In this study measured stem effect correction factor for length of ionization chamber from medical linear accelerator recommend to with the use of stem correction method. For a model of the Farmer-type chamber, were used to calculate the beam quality correction factor. These interactions contribute to the apparent measured exposure. Additionally, it needs to consider ionization chamber use of small volume and stem effect of cable by a large field. Linear accelerator generated photons energy and increased dose repeatedly measured by using stem correction method. Stem effect was dependence of the energy and increases with photon energy conditions improved of beam quality. In conclusion, stem effect correction factor was measured within 0.4% calculated according to the exposures stem length and also supposed to determined below 1% of another stem correction method.

• Journal of the Korean Society of Food Culture
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• v.17 no.1
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• pp.49-56
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• 2002

The purpose of this study was to analyze staff satisfaction with staff foodservice in hospitals. The study compared the hospital staff's expectations and perceptions of foodservice. The quality satisfaction values were indicated as the differences between their expectations and perceptions. The subjects were 643 hospital staff in 11 Daegu . Kyungpook hospitals. Written questionnaires were used to collect the data. The completion rate was 76.9%. There were 17 attributes for foodservice quality, which were divided by factor analysis into four main quality factors; sensory, nutrition, sanitation and service. The high expectation and low perception items on the expectation and perception grid were: seasoning of the meals, taste of the meals, variety of the menu, nutritional considerations, cleanliness of the dishes, and prompt handling of meal complaints. On all the attributes measured, expectations were higher than perceptions. The quality satisfaction values were all negative. There were highly significant(p<0.001) correlations between quality satisfaction and variety of the menu(r=0.783), nutritional considerations(r=0.770), prompt dealing with meal complaints(r=0.762), cleanliness of meals(r=0.689), and courtesy of employees (r=0.653). There is a need to improve taste, menu variety, nutrition, sanitation, speed of handling meal complaints, and courtesy.

• The Korean Journal of Pain
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• v.34 no.2
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• pp.139-155
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• 2021

The quality of subgroup analyses (SGAs) in chronic non-cancer pain trials is uncertain. The purpose of this study was to address this issue. We conducted a comprehensive search in MEDLINE and EMBASE from January 2012 to September 2018 to identify eligible trials. Two pairs of reviewers assessed the quality of the SGAs and the credibility of subgroup claims using the 10 criteria developed by Sun et al. in 2012. The associations between the quality of the SGAs and the studies' characteristics including risk of bias, funding sources, sample size, and the latest impact factor, were assessed using multivariable logistic regression. Our search retrieved 3,401 articles of which 66 were eligible. The total number of SGAs was 177 of which 52 (29.4%) made a subgroup claim. Of these, only 15 (8.5%) were evaluated as being of high quality. Among the 30 SGAs that claimed subgroup effects using an appropriate method of performing interaction tests, the credibility of only 5 were assessed as high. None of the subgroup claims met all the credibility criteria. No significant association was found between the quality of SGAs and the studies' characteristics. The quality of the SGAs performed in chronic pain trials was poor. To enhance the quality of SGAs, scholars should consider the developed criteria when designing and conducting trials, particularly those which need to be specified a priori.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.1
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• pp.1-8
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• 2003

When solving the problems of electric power quality the converters with high Power factor are useful for the DC arc furnace power supply. In this paper, resonant converters of 50(60) Hz AC to DC arc described, where in each period of network voltage the capacitor and inductor of an oscillatory circuit are switched from series into parallel and vice versa parametrically. The duration of series and parallel connection and also the transformation ratio are dependent on load. Parallel oscillatory circuit restricts the short circuit current. These converters have high power factor from no-load to short-circuit and fit very well to supply are furnaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.173-176
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• 2004

The piezoelectric ceramics for AE sensor piezoelectric devices are desirable to possess higher resonance vibrations. The compositions of $0.9Pb(Zr_xTi_{1-x})O_3-0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$ (PZT-PMNS) in this work are selected for obtaining especially large electromechanical coupling factor, high mechanical quality factor and high Curie temperature. This ceramic has higher piezoelectric activity and higher electromechanical coupling factor, but the ceramic has lower Curie temperature. The piezoelectric and dielectric characteristics of PZT-PMNS ternary system are investigated as functions of $Ti^{2+}$, $Zi^{2+}$ mol rate. As the results, MPB(morphotropic phase boundary) in this piezoelectric ceramic is x=0.522. Resonance vibrations of PZT ceramics are investigated as ball-bearing drop test. For the use of AE sensor that driving with pre-amplifier, filter circuit after packed this ceramic and an elastic body.