• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권4호
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• pp.173-178
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• 2003

The rotational force of ultrasonic motors is able to get from the frictional force of elliptical vibration by contact between rotor and stator. Generally, ultrasonic motors are suitable for driving at resonant frequencies of about 20∼80［KHz］. The driving characteristics of ring type ultrasonic motors are the object of this study. A two-phase driving signal is delivered to the tested ultrasonic motor, which has a $90^0$ phase difference respectively with both sine and cosine voltage waveforms. The driving frequency is almost equal to the mechanical resonant frequency for the proper operation, and the driving signal is supplied by the two-phase parallel resonant inverter. The validity of the proposed driving method is verified by experimental results with stable operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1058-1060
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• 2004

This paper presents a characteristic analysis method for an air gap flux density of axial-flux type brushless dc (BLDC) motor. The magnetic flux density for the torque, and vertical force characteristics is calculated by using analytical method, based on the concept of magnetic charge. The calculated results by the presented method is compared with those by 3 dimensional finite element method (3D FEM). Using the presented method, the characteristics of single and double sided axial-flux type BLDC motors are investigated through distributions of air gap flux density.

• 한국정밀공학회지
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• 제14권8호
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• pp.146-154
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• 1997

Solenoid-folw control type ABS is used with a 'dump and reapply' pressure control arrangement instead of using 2/2 (normal open/close) solenoid valves in convensional systems(sol. -sol. control type), a flow control valve is used which replaces the (no) inlet valve. The flow control valve controls fluid flow providing a nearly constant reapply rate( .theta. ) after the dump plase of ABS operation. In this study, to investigate a characteristics of brake pressure by PWM control, test rig was consisted of ABS hydraulic modulator, digital controller, pneumatic power supply and brake master cylinder. For comparison with experi- mental results, system modelling and computer simulation were performed. As a result, experiment results showed fairly agreement with the simulation. Also, it is shown that the pressure gradient (tan .theta. ) is affected by pressure, frequency, duty ratio and expressed with an exponential funtion.

• 한국농촌건축학회논문집
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• 제23권4호
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• pp.21-29
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• 2021

The purpose of this study is to present the basic direction of the desirable spatial plan for elderly care facilities by analyzing the spatial characteristics of elderly care facilities in gyeongnam-province. As a research method, 189 elderly care facilities in gyeongnam-province were investigated for location conditions, site area, floor area, total floor area, and space composition. In addition, the area of each specific space was analyzed for two elderly care facilities with a typical floor plan. The results of the survey and analysis are as follows. First, the average number of people in the facility was 53.8, and the number of people in the facility needs to be planned to be medium or less so that they can live in a more comfortable environment in the future. Second, in the location type, it was found that many facilities were distributed in the order of suburban and rural type, urban type, mountain type, and waterfront type. In addition, in terms of facility space composition, the proportion of detached facilities was 50.8%. Complex facilities require a reasonable plan in consideration of the location type and other functional facility characteristics. Third, the average total floor area per person of elderly care facilities was 27.57m². There is a limit to constructing a unique nursing space. In the composition of bedrooms, quadruple rooms account for 67.4%, but it is necessary to expand the proportion of bedrooms that can be used by fewer people.

• 한국작물학회지
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• 제44권1호
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• pp.59-63
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• 1999

Yield and growth characteristics were compared for five rice cultivars; a new Tongil-type, so called "super-rice", Dasanbyeo, an old Tongil-type Milyang 23, two japonicas Dongjinbyeo and Ilpumbyeo, and a new plant type (NPT)line IR65600-27-1-2. The objective of this stusy was to clarify the high yielding capacity of Dasanbyeo in terms of growth characteristics. The average grain yield (9 t/ha) of Dasanbyeo was higher than that of Milyang 23 by ca. 9% that of japonicas by 20 to 30%, and that of NPT line by ca. 100%. The higher grain yield of Dasanbyeo was attributable not only to the greater dry matter production but also to the higher harvest index (HI). Dasanbyeo showed the greatest dry matter at harvest owing not only to the rapid leaf expan-sion at early growth stage and the resulting high LAI through the entire growth stage but also to the high NAR despite the high LAI. The rapid leaf expansion of Dasanbyeo at early growth stage seemed to be related in part to the profuse tillering capacity. HI was 0.53 in Dasanbyeo, 0,51 in Milyang 23, 0.41 in japonicas, and 0.35 in NPT line. Dasanbyeo was indebted for its higher HI to the relatively high grain filling ratio in spite of a much greater sink size than the other cultivars. Dasan had a greater source to sink ratio during grain ripening as measured by LAD/spikelet and dry matter production/spikelet which showed positove correlations with the grain ripening ratio. New plant type (NPT) line showed the lowest grain yield owing to the small sink size and the low grain filling ratio which seemed to have resulted from the abundant occurrence of weak-strength spikelets. The weak sink strength, in turn, seemed to have suppressed photosynthesis during the grain ripening stage.

• 대한치과기공학회지
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• 제42권3호
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• pp.240-247
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• 2020

Purpose: This study aimed to employ a Q-methodological approach that can understand the characteristics of each type according to the subjective structures of humans, to help understand type-specific characteristics and to provide a basis for creating the image of dental technicians among dental technology students based on the characteristics of each type. Methods: The Q-methodology was used for this study. 120 Q-statements were obtained from a qualitative survey of 120 students of the department of dental technology. To select the Q-sample, the Q-population was categorized by taking several repeated readings. The selected statements were reviewed and revised by experts and 33 Q-samples were finally selected. The data were then analyzed using the PQ method program. Results: Among 42 P specimens, 22 were classified into type 1, 9 types 2, and 11 types 3. "Type 1" recognizes the image of dental technicians positively and optimistically (Z=1.29) (Z=1.74), but it is named "self-development oriented" in the sense that steady self-development must be underpinned (Z=1.37). "Type 2" agreed strongly that they could work for a lifetime without age or gender discrimination (Z=2.09). This type was referred to as "professional-oriented" because the recognition of dental technicians is more focused on "professional." "Type 3" was tagged "pride-oriented," showing the strongest agreement that they can be proud of their job as healthcare workers (Z=1.08). Conclusion: Many studies on such an image should be carried out to determine the importance of occupational images and establish desirable status for dental technicians to continue developing.

• 한국주거학회논문집
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• 제10권2호
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• pp.223-234
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• 1999

The purpose of this study was to provide basic information for future residential flooring planning by identifying differences in preference for flooring materials of livingroom by characteristics of housewives living in apartment housing and by describing their perception of residential flooring materials and by analyzing their degree of satisfaction with the current flooring materials of livingroom. For this purpose, a survey was conducted by 281 housewives who lives in apartment, and analyzed by using frequency, percentage, mean, factor analysis, χ² test, t-test, one-way ANOVA and Duncan's Multiple Range test. The results of the study were obtained as follows: 1) The most preferred flooring materials was wood in the livingroom. Also, most of the reasons for preferred this flooring materials were good for health and good texture. 2) As a result of typifying housewives' perceptions of residential flooring materials, it was classified into fashoin-pursuit type, personality-expression type, beauty-pursuit type, health-pursuit type and practicality-pursuit type. 3) In the degree of satisfaction with the current flooring materials of livingroom, wood showed the highest level of satisfaction. 4) Differences in the degree of satisfaction with the current flooring materials of livingroom by personal characteristics of residents were analyzed. As results, it was found that the group who were later stage of family life cycle and experienced in replacing the flooring materials showed higher degree of satisfaction with the current flooring materials of livingroom.

• 물과 미래
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• 제29권6호
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• pp.225-235
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• 1996

본 연구에서는 계단식어도의 격벽 형상에 따른 수리학적 특성과 어류의 상류이동에 미치는 효과를 다루고 있으며, 상류이동이 용이하도록 격벽의 적정 형태를 제시하는 것으로 하였다. 격벽 형상에 따른 수리학적 특성을 조사하고 적정 형태를 결정하기 위해 수리실험을 실시하였다. 실험결과 zig-zag 형태로 설치된 작은 notch를 가진 직사각형 격벽이 notch가 없는 단순 직사각형 격벽이나 사다리꼴 형태의 격벽보다 좋은 것이며이 밝혀졌는데, 이는 수위 저하시에도 어류의 상류이동이 가능하고 더우기 상류이동을 용이하게 하는 notch를 통한 낙하 흐름을 형성하기 때문인 것으로 판단되었다. Notch는 월류 최대유속이 어류의 유영한계유속을 넘지 않는 범위 내에서 표면류를 지속하도록, 즉 무차원유량 값이 0.27과 0.41 범위 내에 들도록 설계하는 것이 바람직한 것으로 나타났다.

• 오토저널
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• 제13권3호
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• pp.32-42
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• 1991

In SI engine research the pressure data in cylinder is the most important fundamental ones leading to engine efficiencies and performances. It is, therefore, necessary to obtain accurate pressure data and yet it is often impossible to install a reliable data producing, flush-mounted type pressure transducer in a cylinder of small and medium size multicylinder SI engines. When flush mounting the transducer is not possible, the spark-plug type pressure transducer is commonly used as an alternative. In this case, the transmission tube of spark-plug type pressure transducer introduces distortions in the pressure signal. Efforts were made to understand the dynamic characteristics of spark-plug pressure transducer by shock tube tests and real engine experiments. In engine experiment the cylinder pressure data were simultaneously obtained by both flush mounted and spark-plug type pressure transducers of certain transmission tube geometry. Those pressure data collected by spark-plug type pressure transducer were tested for correction to flush mounted ones by the application of transfer function. As a result of the calibration the IMEP difference between F/M data and improved S/P data was shown to be corrected about 75-98% from the original ones.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.476-479
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• 1997

The focus of this paper is to implement of virtual plant using module concept for the dynamic simulation of drum type boiler and to simulate the control trends of dynamic characteristics. MAtlab & Simulink is used for implement virtual plant & analyzation the dynamics & control trends. They are available for analyzing the dynamic characteristics of drum type Boiler by means of applying well measured data to virtual plant.