• Journal of Power Electronics
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• v.12 no.3
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• pp.429-438
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• 2012

This paper presents the use of a novel, single-stage high-power-factor electronic ballast with a symmetrical class-DE low-$d{\upsilon}$/$dt$ resonant rectifier as a power-factor corrector for fluorescent lamps. The power-factor correction is achieved by using a bridge rectifier to utilize the function of a symmetrical class-DE resonant rectifier. By employing this topology, the peak and ripple values of the input current are reduced, allowing for a reduced filter inductor volume of the EMI filter. Since the conduction angle of the bridge rectifier diode current was increased, a low-line current harmonic and a power factor near unity can be obtained. A prototype ballast, operating at an 84-kHz fixed frequency and a 220-$V_{rms}$, 50-Hz line input voltage, was utilized to drive a T8-36W fluorescent lamp. Experimental results are presented which verify the theoretical analysis.

• Korean Journal of Applied Biomechanics
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• v.26 no.3
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• pp.265-272
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• 2016

Objective: The aim of this study was to analyze X-factor, triple X-factor, and the center of pressure (COP) according to the feel of golf driver swing. Method: For this research, 9 golfers from the Korea Professional Golfers' Association (age: $30.11{\pm}2.98yrs$, height: $178.00{\pm}8.42cm$, weight: $76.22{\pm}8.42kg$, experience: $10.06{\pm}3.11yrs$) were recruited to participate in the experiment. Twelve Motion Analysis Eagle-4 cameras were installed and an image analysis was conducted by using the NLT (non-linear transformation) method, and 2 units of Kistler type 5233A dynamometer were used to measure ground reaction force. The sampling ratio was set at 1000 Hz. The golfers each took 10 swings by using their own driver, and chose the best and worse feel from among 10 shots. A paired-sample t-test was used to analyze the results. Results: In regard to feel, no change in head speed, X-factor, and the triple X-factor's X-factor stretch, hip rise, and head swivel, was observed (p>.05). Regarding ground reaction force, a difference was observed between the top of the backswing (p<.05) and impact (p<.05) in the vertical force of the left foot. For COP, a difference was also observed between the mid backswing (p<.001), late backswing (p<.001), and top of the backswing (p<.05) for the right foot X-axis and Y-axis mid follow through (p<.01). Conclusion: It can be reasoned that, irrespective of feel, the head speed, X-factor and triple X-factor's X-factor stretch, hip rise and head swivel did not have an effect on drive distance for domestic golfers, and the vertical reaction force of the left foot and left-right movement span's pressure dispersal of the right foot had an increasing effect on drive distance.

• Journal of the Korean Society of Food Culture
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• v.22 no.2
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• pp.210-217
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• 2007

The purpose of this study was to elicit types of food-related lifestyle of undergraduates and to examine the relationship between each ape of food-related lifestyle and an attribute of selecting a restaurant. Self-administrated questionnaires were completed by 368 students and data were analysed by frequency, factor, reliability and canonical correlation. Five factors were obtained from factor analysis of food-related lifestyle ; Factor1 'health seeking type', Factor2 'taste seeking type', Factor3 'Popularity seeking type', Factor4 'safety seeking type', Factor5 'mood seeking type'. Restaurant selection attribute were extracted into six factors, Factor1 'taste and service', Factor2 'interior‘, Factor3 'convenient for approach', Factor4 'marketing strategy', Factor5 'food quality', Factor6 ’menu and price‘ Canonical correlation analysis showed two significant functions. Canonical function1 showed that food-related lifestyles of taste seeking type and safety seeking type were indicated to have significant positive relationships with the food qualify, taste and service in the restaurant selection attributes. Canonical function2 also showed that a significant positive relationships between health seeking type and accessibility, and a significant negative relationships between health seeking type and taste & service and between health seeking type and menu & price. Finally the result of the study provide some insight into the types of marketing stratagem that can be effectively used by operator who manage restaurant.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.2
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• pp.93-100
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• 1998

In this paper we analyze the effect of nonlinear gain on laser modulation characteristics applying a small-signal analysis to the rate equation which includes a nonlinear gain term. Also we analyze the resonance frequency and the damping factor which determine laser modulation characteristics, define K factor which is the proportionality factor between resonance frequency and damping factor, and conclude that the decrease in K factor is due to increases in differential gain and no correlation between K factor and nonlinear gain is identified.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.196-198
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• 2003

The low load power factor causes various problems such as the increase of the power loss and the voltage instability. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power troublesome, from which the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is derived and its effects in supplying the reactive power and enhancing the load power factor are analyzed in a small-scale power system. The load power factor sensitivity of the generation cost is applied for determining the locations and capacities of reactive power compensation devices. It is shown that the generation cost can be reduced and the system power factor can be enhanced effectively using the load power factor sensitivity.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.11 s.158
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• pp.1636-1647
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• 2006

The purpose of this study was to provide data that can be used to suggest idealistic anchor's image to capture ratings for the news program and to suggest guide for casting and training anchors for the broadcasting stations by examining the idealistic looks and images of TV news anchors by asking the general viewers who watch TV, The research methods was questionnaire survey. The subjects were 839 male and female audiences in theire 20's and 40's who residing in Seoul and Gyeonggi area. The study results are as follows: 1) The factors that decide impression of a female anchor The factors that decide female anchor's impression were 'specialty factor, friendliness factor, elegance factor, dynamic factor, and attractiveness factor'. 2) The difference in formation of impression according to makeup and hair style of a female anchor In case of specialty and friendliness factors scored high when putting on natural makeup, dynamic factors scored high when putting on elegant makeup, and attractiveness factor when putting on natural and romantic makeup. All factor were high when a female anchor had short-cut style and straight hair 3) Formation of anchor's impression from makeup and hair style according to the perceiver's variables (gender and age) Male and female audiences both gave hish score for a female anchor's specialty such as 'confident and reliable' and friendliness such as 'warm and comfortable' when a female anchor puts on natural makeup. They gave high score for attractiveness factor such as' good impression and refined' when putting on romantic makeup and high score for dynamic factor such as 'positive and confident' when putting on elegant makeup. Both male and female audiences gave high score fur all except friendliness factor when a female anchor had short-cut style compared to bobbed hair and high score far specialty factor when a female anchor had straight hair. The audiences both in their 20's and 40's gave high score for specialty and friendliness when a female anchor put on natural makeup while the perceivers at their 20's gave high score for elegance and dynamic factor when a female anchor put on elegant makeup. The audiences both in their 20's and 40's gave high score for all factors when female anchor had short-cut hair.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.211-220
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• 2011

TOD(Transit Oriented Development) has recently been active, which presents that TOD planning elements should be comprehensively taken into consideration in order to enhance domestic transit ridership by changing environments in rail station areas and an empirical analysis on the type of rail station areas and transportation demand should be a prerequisite for usage of future development planning. This study aims to grasp a variety of TOD of influence factors in Seoul rail station area and to perform analysis to identify relationship between public transportation demand and these TOD design factors. To make it come true, we gathered data with respect to Density, Diversity, and Accessibility as representative TOD planning elements and carried out factorial and regression analysis. Consequently, we drew 7 influence factors base on factorial analysis: Factor 1(Diversity/ -Use Mix(LUM)), Factor 2(Density/development density), Factor 3(Accessibility/public transportation facility supply), Factor 4(Design/street design), Factor 5(Green/access mode (pedestrian, bike), Factor 6(Design/subway size), Factor 7(Accessibility/Public transit operation) As the result of model development by using factorial and regression analysis, positive influence factors on passenger flow in rail station area are Factor 1(Diversity : Land-Use Mix), Factor 3(Accessibility : public transportation facility supply), Factor 2(Density : development density), Factor 5(Design/ access mode) and Factor 6(subway size) Next, negative influence factor on passenger flow in rail station area shows Factor 7(Accessibility/Public transit operation) as the most influential factor. This is because the growth of service interval of linked subway and bus leads to reduced demand.

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.525-534
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• 2007

It is a common practice in many research areas that multiple range tests for a between subject factor such as Tukey are applied to a within subject factor in a repeated measures design. Tukey procedure, however, sometimes detects no pairs with different means even when the hypothesis of all equal level means is rejected. This study attempts to provide a rationale for the proposition that Tukey is inappropriate post hoc procedure for a within subject factor in which the observations are correlated. We introduce two multiple range tests, Bonferroni and Scheffe, for a within subject factor and show that Bonferroni is more appropriate than Scheffe for pairwise multiple comparisons. Subsequent simulation study indicates that Tukey has significantly less power than Bonferroni in detecting actual difference between means of some pairs when the observations of a within subject factor are highly correlated.

• Journal of Industrial Technology
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• v.18
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• pp.35-41
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• 1998

A watershed terrain factor is known to the very important in studies of a stream and a watershed. We have obtained the terrain factor in map directly or we have generated it in a digitalized map. In this study, DTED(Digital Terrain Elevation Data) offering in DMA(Defense Mapping Agency) was used to create a stream and a watershed and to extract the terrain factor. As comparison of the factors gererated in digitalized map the terrain factors extracted in DTED, DTED could be used to extract a terrain factor for a watershed management.

• Structural Engineering and Mechanics
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• v.87 no.4
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• pp.363-373
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• 2023

Since the first family of structure-dependent methods can simultaneously integrate unconditional stability and explicit formulation in addition to second order accuracy, it is very computationally efficient for solving inertial problems except for adopting auto time-stepping techniques due to no nonlinear iterations. However, an unusual stability property is first found herein since its unconditional stability interval is drastically different for zero and nonzero damping. In fact, instability might occur for solving a damped stiffness hardening system while an accurate result can be obtained for the corresponding undamped stiffness hardening system. A technique of using a stability factor is applied to overcome this difficulty. It can be applied to magnify an unconditional stability interval. After introducing this stability factor, the formulation of this family of structure-dependent methods is changed accordingly and thus its numerical properties must be re-evaluated. In summary, a large stability factor can result in a large unconditional stability interval but also lead to a large relative period error. As a consequence, a stability factor must be appropriately chosen to have a desired unconditional stability interval in addition to an acceptable period distortion.