• Title/Summary/Keyword: stepwise method

Search Result 779, Processing Time 0.026 seconds

Numerical Study on Floating-Body Motions in Finite Depth

  • Kim, Tae-Young;Kim, Yong-Hwan
    • International Journal of Ocean System Engineering
    • /
    • v.2 no.3
    • /
    • pp.176-184
    • /
    • 2012
  • Installing floating structures in a coastal area requires careful observation of the finite-depth effect. In this paper, a Rankine panel method that includes the finite-depth effect is developed in the time domain. The bottom boundary condition is satisfied by directly distributing Rankine panels on the bottom surface. A stepwise analysis is performed for the radiation diffraction problems and consequently freely-floating motion responses over different water depths. The hydrodynamic properties of two test hulls, a Series 60 and a floating barge, are compared to the results from another computation program for validation purposes. The results for both hulls change remarkably as the water depth becomes shallower. The important features of the results are addressed and the effects of a finite depth are discussed.

Factors Influencing Health Promoting Behaviors of University Students using Pender's Model (Pender 모형을 활용한 대학생의 건강증진 행위와 영향요인)

  • Kim, Hee-Kyung
    • Women's Health Nursing
    • /
    • v.12 no.2
    • /
    • pp.132-141
    • /
    • 2006
  • Purpose: The purpose of this study was to supply basic data for a health promoting program and to elevate the level of it by examining whether university students' health promoting behaviors were related to health perception, health concept, self- esteem, perceived benefits of action, perceived barriers of action, perceived self-efficacy, activity-related affect, social support, preference, prior related behavior, and a plan for action. Method: Subjects were 192 university students in K city. Data collection method was a structured questionnaire. Data was analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation, and stepwise multiple regression. Result: The most powerful predictor was previous related behavior (36%). Altogether previous related behavior, health status, a plan for action, perceived self-efficacy and number of admissions were proven to account for 57% of health promoting behaviors. Conclusion: It suggested that prior related behavior, health status, a plan for action, perceived self-efficacy, and number of admissions should be considered when developing a students' health promoting program.

  • PDF

A Study on the Optimal Vacuum Drying Conditions of Tobacco for Moisture Measuring (진공건조오븐과 Karl-Fischer법을 이용한 담배의 최적 수분측정법 연구)

  • Park, Bae-Sik;Kim, Bong-Ju;Park, Heung-Jin
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.19 no.2
    • /
    • pp.159-161
    • /
    • 1997
  • A study on the optimal drying condition by a vacuum drying oven was done using shredded tobacco lamina and commercial cigarettes ('This'). Changes in the mass of the experimental material were monitored for about 50 hrs at 6 different temperatures (5$0^{\circ}C$~10$0^{\circ}C$, 1$0^{\circ}C$ stepwise) while continuously operating a vacuum pump. After 30 hrs, small amount of samples from each material were taken sequentially to monitor changes in moisture content using a Karl-Fischer method (Metrohm KF 701 Titrino). Absolute moisture contents calculated from the measurements indicated an ideal data distribution could be obtained by drying at temperatures between 7$0^{\circ}C$~8$0^{\circ}C$. Results from cigarette products which contains humectant and tobacco lamina without it were compared.

  • PDF

Predictive Factors of Adolescents' Illicit Drug Use (청소년의 비치료적 약물사용에 관한 예측요인)

  • Kim, Hee-Young
    • Research in Community and Public Health Nursing
    • /
    • v.18 no.1
    • /
    • pp.136-145
    • /
    • 2007
  • Purpose: This study was attempted to illuminate danger signals through an extensive analysis of factors influencing adolescents' illicit drug use. On this basis, it built predictive factors of adolescents' illicit drug use. Method: A questionnaire was distributed to 1,238 subjects living in Seoul, and of them 1,082 answers were analyzed using the SAS 8.2 program. Also logistic regression analysis was conducted based on the stepwise selection method for constructing the predictive factors. Results: The findings of this study are as follows. Individual-related factors were psycho-somatic symptoms, self-esteem, fortune delinquent experience, and sexual-violence delinquent experience. Home-related factors were insincerity, threatening and the assessment of the parent (rearer)-adolescent communication type. Society-related factors were affection of friends and friends' attitude toward delinquency. Conclusion: These findings of this study suggest that a broad intervention program should be provided to nurture wholesome youth culture related to illicit drug use. It is also recommended that a variety of individual, home and society-related programs should be developed for drug users.

  • PDF

Analysis of payload compartment venting of satellite launch vehicle

  • Mehta, R.C.
    • Advances in aircraft and spacecraft science
    • /
    • v.4 no.4
    • /
    • pp.437-448
    • /
    • 2017
  • The problem of flow through the vent is formulated as an unsteady, nonlinear, ordinary differential equation and solved using Runge-Kutta method to obtain pressure inside payload faring. An inverse problem for prediction of the discharge coefficient is presented employing measured internal pressure of the payload fairing during the ascent phase of a satellite launch vehicle. A controlled random search method is used to estimate the discharge coefficient from the measured transient pressure history during the ascent period of the launch vehicle. The algorithm predicts the discharge coefficient stepwise with function of Mach number. The estimated values of the discharge coefficients are in good agreement with differential pressure measured during the flight of typical satellite launch vehicle.

A Study on the Optimum Design of Multi-Object Dynamic System for the Rail Vehicle (철도차량 동적 진동특성을 고려한 다목적함수 최적설계)

  • Park, Chan-Kyoung;Lee, Kwang-Ki;Kim, Ki-Hwan;Hyun, Seung-Ho;Park, Choon-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2000.06a
    • /
    • pp.894-899
    • /
    • 2000
  • Optimization of 26 design variables selected from suspension characteristics for Korean High Speed Train (KHST) is performed according to the minimization of 58 responses which represent running safety and ride comfort for KHST and analyzed by using the each response surface model from stochastic design experiments. Sensitivity of design variables is also analyzed through the response surface model which ineffective design prameters to the performance index are screened by using stepwise regression method. The response surface models are used for optimizing design variables through simplex algorism. Values of performance index simulated by optimized design parameters are totally lower than those by initial design parameters. It shows that this method is effective for optimizing multi-design variables to multi-object function.

  • PDF

An Analysis of the Factors Affecting Smoking Cessation Intention of Smoking Adolesoents (흡연 청소년의 금연의향에 미치는 요인분석)

  • Lim, Eun-Sun;Yoo, Jang-Hak
    • Research in Community and Public Health Nursing
    • /
    • v.17 no.2
    • /
    • pp.253-262
    • /
    • 2006
  • Purpose: This study was done to evaluate the predictive factors of smoking cessation intention of smoking adolescents at H. district in Chungchungnam-do. Method: A convenience sample was recruited from a public health center at H. district in Chungchungnam-do. A total of 100 smoking adolescents were enrolled in this study. A self-report survey method was used to identify the predictive factors related to smoking cessation. Result: A forward stepwise logistic regression analysis identified four factors associated with smoking cessation intention of smoking adolescents: accompanied friends during the smoking cessation program (OR=20.14), preparation for smoking cessation (OR=5.12), smoking cessation knowledge after the smoking cessation program (OR=1.41), and the number of cigarettes (OR=0.15). Conclusion: Based on this study results, the effective programs in reducing adolescent smoking rates should include components to accompany peers, increase the knowledge of smoking impact, and the benefit of smoking cessation.

  • PDF

Study for Improving Properties of Squid Viscera Oil Using Transesterification and Adsorption (에스테르 교환반응과 흡착제를 이용한 오징어 내장유의 품질 개선)

  • Roh, Myong-Kyun;Uddin, Salim;Chun, Byung-Soo
    • Journal of Marine Bioscience and Biotechnology
    • /
    • v.2 no.4
    • /
    • pp.257-262
    • /
    • 2007
  • Squid viscera oil was investigated by pretreatment method for enhancing the commercial value. Transeterification was performed to reduce rancidity of the oil, off-flavor was removed by using activated carbon adsorption. Analysis using ATD (Automatic Thermal Desorber) and GC/MG shows the efficacy of off-flavor removement. The rates of Transesterification employing inorganic catalyst and biocatalyst were tested, respectively. With stepwise addition of ethanol, the most efficiency of the reaction was achieved by inorganic catalyst. The efficiency of the reaction was estimated by acid value corresponding to rancidity of reaction product.

  • PDF

A Method to Adjust the Optimal Phase Angle of Resolver Excitation Signal (레졸버 여자신호의 최적 위상 조정 방법)

  • Kim, Kyung-Seo
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.15 no.3
    • /
    • pp.252-258
    • /
    • 2010
  • If the speed measurement of resolver and the generation of PWM signals are implemented with single microcontroller, it is easy to reduce the system cost and to avoid the switching noise of inverters. To avoid the switching noise and to improve the accuracy of measurement, PWM switching and A/D sampling of the resolver should be synchronized. Phase angle of the resolver excitation signal is increased in stepwise manner, then, the output signal of the resolver is measured in each step. From the measured data, the optimal phase angle of resolver excitation signal is estimated using the least square approximation method.

Retention Behavior of Transition Metal ions with Some Complexing Agents on Cation Exchanger

  • Park, Yang-Soon;Joe, Kih-Soo;Lee, Gae-Ho;Han, Sun-Ho;Eom, Tae-Yoon
    • Bulletin of the Korean Chemical Society
    • /
    • v.14 no.6
    • /
    • pp.692-696
    • /
    • 1993
  • Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.