• Title/Summary/Keyword: ratio variable

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A Study on the Variation of Physical Properties by the Water to Cement Ratio and the Mixing Speed for Grout Materials (그라우트재의 물시멘트비 및 혼합속도에 의한 물성변화에 관한 연구)

  • 천병식;김진춘;장의웅;송성호;이준우
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.445-452
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    • 2001
  • Generally, OPC(ordinary portland cement) is used for grouting in Korea, and bentonite has usually been added to prevent the deposition of cement particles. The dispersion of CB(cement bentonite) grout is influenced by variable factors i.e. water to cement ratio, particle size of cement, kind of bentonite, adding volume, methods of adding, viscosity of CB grout materials and curdling time. Among variable factors, the viscosity of CB grout materials is influenced by the dispersion, and dispersion is improved as increasing the mixing speed. In this paper, described a suitable mixing speed of the High Speed Mixer in field, engineering characteristics of CB grout materials vary with the water to cement ratio and the mixing speed as well as confirming the state of dispersion.

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A Numerical Study of Valve Lift on the Flow Characteristics in Gasoline Engine (가솔린 엔진에서 밸브리프트에 따른 유동특성에 관한 수치해석적 연구)

  • Kim, Dae-Yeol
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.4
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    • pp.81-88
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    • 2008
  • Flow characteristics have one of the effects in the process of engine. The numerical analysis makes it possible to predict the flow fields. This paper presents characteristics of steady flow according to variation of valve lift in a gasoline engine. The numerical computations have been made to observe the pressure distribution in accordance with the variable valve lift. Characteristics of tumble flow and swirl flow according to the variable valve has also been investigated. We could find that tumble ratio and swirl ratio is different between with/without PDA valve. The steady flow test was simulated through three-dimensional analysis on intake port design for comparing with experimental data and confirming the feasibility of applying analytic method. As a result, this study shows the possibility of the usage of numerical simulation to predict the flow characteristics for gasoline engine.

The Impact of Operating Cash Flows on Financial Stability of Commercial Banks: Evidence from Pakistan

  • ELAHI, Mustahsan;AHMAD, Habib;SHAMAS UL HAQ, Muhammad;SALEEM, Ali
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.11
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    • pp.223-234
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    • 2021
  • This study aims to examine whether operating cash flows influence banks' financial stability in Pakistan. The study employed annual panel data collected from annual reports of 20 commercial banks listed on the Pakistan Stock Exchange for the year 2011 to 2019. Free cash flow yield was taken as the dependent variable while cash flow ratio was selected as the independent variable, and net interest margin, income diversification, asset quality, financial leverage, the cost to income ratio, advance net of provisions to total assets ratio, capital ratio, financial performance, breakup value per share and bank size were taken as control variables. The study performed ordinary least square technique, random and fixed effects models, Hausman test, Lagrange multiplier test, descriptive and correlation analysis. Results showed that operating cash flows and net interest margin significantly and positively influenced banks' financial stability while the cost to income ratio and advances net of provisions to total assets ratio significantly and negatively associated with banks' financial stability. To improve financial stability, banks should become more cost-effective and enhance their liquidity levels by lowering lending activities. In the future, it would be useful to compare commercial and investment banks, also Islamic and conventional banks in the same research setting.

Design of CVT Composed of a K-H-V type Differential Gear Unit and a V-Belt Drive (K-H-V형 차동기어장치와 V-벨트식 기구를 결합한 무단변속기의 설계)

  • 김연수;박재민;정찬길;최상훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.799-802
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    • 2002
  • Continuously variable transmission(CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit(CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral.

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Compound CVT with K-H-V Differential Gear and V-belt Drive

  • Kim, Yeon-Su;Choi, Sang-Hoon
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.1
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    • pp.5-14
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    • 2005
  • Continuously variable transmission (CVT) mechanisms combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit (CVU). For the 24 different mechanisms, 12 of them are power circulation modes while the other 12 are power split modes. Some useful theoretical formulas related to speed ratio, power flow and efficiency were derived and analyzed. These mechanisms have many advantages: they decrease CVT size and weight, increase overall efficiency, extend speed ratio range, and generate geared neutral. Compound CVTs were developed by combining the power circulation mode and power split mode, which can offer backward motion, geared neutral, underdrive and overdrive.

Characteristics on the Output Coupled Type CVT Combined Differential Gear Unit (차동기어장치를 적용한 출력축 연결방식 무단변속기의 특성해석에 관한 연구)

  • Choi, Sang-Hoon;Kim, Yeon-Su
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.205-215
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    • 2001
  • Continuously variable transmission(CVT) mechanisms considered here combine the functions of a 2K-H I type differential gear unit and a V-belt continuously variable unit(CVU). One shaft of the V-belt CVU is connected directly to the differential gear unit and remaining shaft of it is linked to the output shaft. These mechanisms have many advantage which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. In this paper six different mechanisms of output coupled type CVT are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed, and theoretical analysis are proven by various experiments.

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Adaptive Shot Change Detection using Mean of Feature Value on Variable Reference Blocks and Implementation on PMP

  • Kim, Jong-Nam;Kim, Won-Hee
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.229-232
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    • 2009
  • Shot change detection is an important technique for effective management of video data, so detection scheme requires adaptive detection techniques to be used actually in various video. In this paper, we propose an adaptive shot change detection algorithm using the mean of feature value on variable reference blocks. Our algorithm determines shot change detection by defining adaptive threshold values with the feature value extracted from video frames and comparing the feature value and the threshold value. We obtained better detection ratio than the conventional methods maximally by 15% in the experiment with the same test sequence. We also had good detection ratio for other several methods of feature extraction and could see real-time operation of shot change detection in the hardware platform with low performance was possible by implementing it in TVUS model of HOMECAST Company. Thus, our algorithm in the paper can be useful in PMP or other portable players.

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Development of Blood Pressure Estimation Algorithm Using Variable Characteristic Ratios on Oscillometric Method (진동법에서 가변 특성 비를 이용한 혈압 추정 알고리즘의 개발)

  • Shin, Joon
    • Journal of Biomedical Engineering Research
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    • v.30 no.6
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    • pp.510-515
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    • 2009
  • In this paper, variable characteristic ratio algorithm based on oscillometric method is proposed to enhance the accuracy of blood pressure measurement. We combined the slope-based approach and fuzzy inference technique to change the characteristic ratios of height-based method. The proposed algorithm was assessed on 255 measurements from 85 subjects and compared with the conventional height-based algorithm. The testing results showed that the developed algorithm achieved an overall grade A for both systolic and diastolic blood pressures according to the BHS protocol. And, mean standard deviation between the observers and the developed algorithm were 5.71mmHg and 6.29mmHg for systolic and diastolic pressures respectively, which also fulfilled the AAMI criteria. In conclusion, this algorithm was successfully developed and recommended for further clinical trials with the wider adult population.

Performance of CVTs Composed of a Differential Gear Unit and a V-belt Drive (차동기어장치와 V-벨트식 변속기구를 결합한 무단변속기의 성능)

  • 최상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.199-208
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    • 2003
  • Continuously variable transmission (CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit (CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral.

Compound CVT realizing Power Circulation Mode and Power Split Mode (동력순환형과 동력분류형을 구현 가능한 복합형 무단변속기)

  • Choi Sang-Hoon;Kim Yeon-Su
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.4
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    • pp.96-103
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    • 2005
  • We designed the compound CVT(Continuously Variable Transmissions) by combining power circulation mode and power split mode, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU(Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments for efficiency, speed ratio, power flow, and power transmission ratio. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.