• Title/Summary/Keyword: stepwise multiple linear regression analysis

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Practical modeling of cigarette ventilation rate

  • Kim, Young-Hoh;Lee, Moon-Yong;Rhee, Kyu-Seo;Lee, Dong-Wook
    • Journal of the Korean Society of Tobacco Science
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    • v.21 no.2
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    • pp.109-118
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    • 1999
  • A model predicted describing the effect of cigarette making materials on the level of filter ventilation was developed and evaluated. The developed model was expressed in terms of a linear and quadratic relationship which was validated with experimental measurements for different porosity of plug wrap and tipping paper, unencapsulated pressure drop of filter plug and cigarette column and vent position. Forty-six experimental frequencies were determined as a result of using three levels with five factors Box-Behnken design and analyzed by the multiple regression analysis with backward stepwise in STATISTICA/PC under restricted conditions. The four factors, except filter pressure drop variable, were statistically significant at the level of 0.05 but most of all linear by linear interactions were comparatively lower significant. By the analysis of linear and quadratic regression coefficient, filter ventilation of the cigarette was affected by porosity of plugwrap (5.87, -4.25), porosity of tip paper (5.68, -1.00), vent position (-3.87, 3.08), tobacco column pressure drop (2.56, 0.66), and filter pressure drop (1.50, 0.58) in the decreasing order. It should be emphasized that the major conclusion of this study was not that any particular parameter was linear or quadratic on any limit scale, but that there were highly significant relationships among factors involving linear, quadratic and their interaction and perhaps even linearity between and within factors. While, there is also quite strong evidence that vent position from mouth end and cigarette making materials are reverse relationship on this experimental model. On the basis of the result, it can be concluded that the porosity of the plug wrap and tipping paper has a marked effect on degree of filter ventilation rate. The F-value of plug wrap and tipping paper porosity among five factors were 39.2 and 36.8 respectively with P-value of 0.000 indicating higher significant for both factors. According to the analysis of variance, the model fitted for filter ventilation was significant at 5% confidence level and the coefficient of determination ($R^2$=0.84) was the proportion to variability in the data well fitted for by the model.

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Determination of Chemical Composition of Toasted Burley Tobacco by Near Infrared Spectroscopy (근적외선분광법을 이용한 버어리 토스트엽의 화학성분 분석)

  • 김용옥;정한주;백순옥;김기환
    • Journal of the Korean Society of Tobacco Science
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    • v.17 no.2
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    • pp.177-183
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    • 1995
  • This study was conducted to develop the most precise NIR(near infrared spectrometric) calibration for rapid determination of chemical composition in ground samples of toasted burley tobacco using stepwise, stepup, principal component regression(PCR), partial least square(PLS) and modified partial least square(MPLS) calibration method. The number of wavelength(W) selected by stepup multiple linear regression using: second derivative spectra was as follows: total sugar(TS)-4 W, nicotine-9 W, total nitrogen(TN)-2 W, ash-8 W, total volatile base(TVB)-5 W, chlorine4 W, L of color-6 W, a of color-6 W and b of color-7 W. Comparing the calibration equations followed by each chemical components, the most precise calibration equation was MPLS for 75, a and b of color, PLS for nicotine, ash, TVB, chlorine and L of color and stepup for TN. The standard error of calibration(SEC) and standard error of performance(SEP) between result of near infrared analysis and standard laboratory analysis were 0.18, 0.40% for 75, 0.06, 0.08% for nicotine, 0.18, 0.16% for TN, 0.33, 0.46% for ash, 0.04, 0.03% for TVB, 0.08, 0.06% for chlorine, 0.54, 0.58 for L of color, 0.22, 0.22 for a of color and 0.27, 0.27 for b of color, respectively. The SEC and SEP of ash and TVB were within allowable error of standard laboratory analysis, nicotine, TN and chlorine were 1.2-2.0 times and 75 were 2.1-4.0 times larger than allowable error of standard laboratory analysis. The ratio of SEC and SEP to mean were 1.5, 1.6% for L of color, 3.7, 3.8% for a of color and 1.8, 1.8% for b of color, respectively. Key words : burley tobacco chemistry, near infrared spectroscopy.

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Breast Conserving Therapy and Quality of Life in Thai Females: a Mixed Methods Study

  • Peerawong, Thanarpan;Phenwan, Tharin;Supanitwatthana, Sojirat;Mahattanobon, Somrit;Kongkamol, Chanon
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.6
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    • pp.2917-2921
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    • 2016
  • Background: To explore factors that influence quality of life (QOL) in patients receiving breast conserving therapy (BCT). Materials and Methods: In this sequential mixed methods study, 118 women from Songklanagarind Hospital were included. We used participants' characteristics, Body Image Scale (BIS), and Functional Assessment of Cancer Therapy with the Breast Cancer Subscale (FACT-B) for analysis. The BIS transformed into presence of body image disturbance (BID). Factors that influenced QOL were determined by stepwise multiple linear regression. Forty-one participants were selected for qualitative analysis. Our female researcher performed the semi-structured interviews with questions based on the symbolic interaction theory. Final codes were analysed using thematic analysis along with investigator triangulation methods. Results: Ninety percent had early stage breast cancer with post-completed BCT, for an average of 2.7 years. The median BIS score and FACT-B score were 2 (IQR=10) and 130 (IQR=39). In the regression analysis, an age of more than 50 years and BID were significant factors. As for the value of conserved breasts, two themes emerged: a conserved breast is an essential part of a participant's life and also the representation of her womanhood; the importance of a breast is related to age. Conclusions: Body image influenced QOL in post BCT participants. The conserved breasts also lead to positive and better impact on their body image as an essential part of their life.

Clinical Factors which Affect the Amount and Length of Intravenous Heparin Infusion in Stroke (허혈성 뇌졸중환자의 헤파린 주입량과 주입기간에 영향을 미치는 임상적 요인)

  • Choi, Ja-Yun;Kim, Mi-Won
    • Journal of Korean Biological Nursing Science
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    • v.11 no.1
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    • pp.14-22
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    • 2009
  • Purpose: This study was conducted to examine the clinical factors which affected the amount and the duration of infusion of intravenous (IV) heparin on ischemic stroke. Method: A cross-sectional descriptive study was designed to examine the factors. A total of 101 patients with ischemic stroke from a University hospital in G-city, Korea from January to December, 2006 were participated in this study. Data were analyzed by t- and ANOVA test, correlation coefficient, and stepwise multiple linear regression analysis. Result: This study showed that the patients who have been temporarily stopped to infuse iv heparin for more than one hour, had cardioembolic stroke, and had the lower count of initial red blood cell (RBC) had significantly lower amount of iv heparin infusion per body surface. In addition, this study founded that the patients with lower count of initial RBC and the lower level of initial blood sugar were significantly less likely to have the lower length of iv heparin infusion. Conclusion: Continuous monitoring and controlling the count of RBC and the level of blood sugar are needed to increase the efficacy of iv heparin therapy on ischemic stroke. Further empirical studies should be conducted to support the results of this study.

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Relationship between Environmental Factors and Short-term Variations of Mesozooplankton During Summer in Jangmok Bay, South Coast of Korea (여름철 장목만의 환경요인과 중형동물플랑크톤 단주기 변동과의 상관성)

  • Jang, Min-Chul;Shin, Kyoung-Soon;Jang, Pung-Guk;Lee, Woo-Jin
    • Ocean and Polar Research
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    • v.32 no.1
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    • pp.41-52
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    • 2010
  • Daily samples were collected during summer in order to analyse changes in the mesozooplankton community and to identify the major environmental factors that may influence mesozooplankton abundance in Jangmok Bay. A single site in the bay was sampled 47 times from July to September 2003. Mesozooplankton community, hydrographic (watertemperature, salinity, dissolvedoxygen) and biological (chlorophyll-a, ciliates densities, Noctiluca scintillans densities) factors were determined. The mesozooplankton abundance varied remarkably from 954 to $14,816\;inds.\;m^{-3}$. The six taxa of Evadne tergestina, barnacle nauplii and cypris, Paracalanus parvus s.1., Acartia omorii, Penilia avirostris and Sagitta crassa dominated numerically, contributing 86% of total mesozooplankton abundance. Stepwise multiple linear regression analysis was applied to find correlation between environmental factors and fluctuation in the abundance of dominant species and mesozooplankton. A. omorii was significantly correlated with temperature and N. scintillans densities. E. tergestina was correlated with temperature, salinity, and ciliate densities, whereas P. avirostris was correlated with temperature and dissolved oxygen. Among the environmental factors, mesozooplankton abundance correlated most strongly with N. scintillans densities. Accordingly, N. scintillans may be a key player in controlling the fluctuation of mesozooplankton abundance as a strong competitor for same food resources.

The associations between serum leptin, adiponectin and intercellular adhesion molecule-1 in hypercholesterolemic patients

  • Park, Eun-Ju;Shin, Min-Jeong;Chung, Nam-Sik
    • Nutrition Research and Practice
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    • v.1 no.1
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    • pp.65-69
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    • 2007
  • We examined the associations between adiponectin or leptin and serum ICAM-1 levels in seventy-six hypercholesterolemic patients (mean age 59 yrs, 25 males and 51 females, LDL-cholesterol>=130mg/dL at screening). Blood lipid profiles and HOMA-IR derived from fasting glucose and insulin concentrations were determined. Serum levels of adiponectin, leptin and ICAM-1 were analyzed using ELISA The results showed that serum levels of leptin were positively associated with serum levels of ICAM-1 independent of age, sex and BMI (r=0.392, p<0.001). Serum levels of adiponectin were negatively associated with serum levels of ICAM-1 independent of age, sex and BMI (r=-0.343, p<0.005). Stepwise multiple linear regression analysis showed that serum leptin was an independent factor to be associated with serum ICAM-1 levels after adjusting for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.001). With respect to adiponectin, its association with serum ICAM-1 was attenuated but still significant when further adjustments were made for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.005). In conclusion, this study suggests that adiponectin and leptin are associated with endothelial derived inflammation.

The Development of Evaluation Indicators for the Performance of Defense Core-Technology R&D Projects Using SMR/AHP (SMR/AHP 기법을 활용한 국방핵심기술 연구개발사업 성과평가지표 개발)

  • Lee, Hyung-Jun;Kim, Chan-Soo;Kim, Woo-Je
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.1
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    • pp.70-79
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    • 2009
  • Currently, the investment on Research and Development(R&D) for defense core technology is continuously increasing to maintain advanced country's R&D level. In accordance with this trend, the national defense R&D investment management system is being more strengthening, and importance of performance evaluation is being emphasized more and more. However, the existing indicators of performance evaluation for defense core technology R&D is limited in efficient management because of the qualitative evaluation items and subjective allocation of points. In this paper, we developed a novel indicator for defense core technology R&D performance evaluation through domestic and foreign related literature and inquiry, brainstorming, and analysis techniques by Stepwise Multiple linear Regression(SMR) and Analytic Hierarchy Process(AHP). And we verified effectiveness of proposed indicators of performance evaluation by comparing with the existing evaluation indicators. Our proposed indicators for performance evaluation will create superiority performance on defense R&D fields.

A Study on Keratinized Gingival Thickness in Healthy Korean Adults (한국 성인의 각화치은 두께측정에 관한 연구)

  • Kang, Chul-Heun;Chang, Moon-Taek;Ryu, Sung-Hoon;Kim, Hyung-Seop
    • Journal of Periodontal and Implant Science
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    • v.30 no.1
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    • pp.179-187
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    • 2000
  • The objectives of this study were to measure keratinized gingival thickness in healthy Korean adults, and to correlate the keratinized gingival thickness with width of keratinized gingiva, probing pocket depth and gingival recession.Thickness measurements were performed in 37 Korean dental students using an ultrasonic device(SDM). Width of keratinized gingiva, gingival recession and probing pocket depth were measured with a Williams periodontal probe.The results showed that the keratinized gingival thickness varied from 0.83 mm(canines) to 1.16 mm(central incisors) in the maxilla and, in the mandible, from 0.68 mm(1st premolars) to 1.69 mm(2nd molars). In a stepwise multiple linear regression analysis, 23% of variation of gingival thickness could be explained by width of keratinized gingiva and probing pocket depth. It could be concluded that the keratinized gingival thickness depends on tooth type and correlates with width of keratinized gingiva and probing pocket depth.

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Influence of Nurses' Attitude toward Death and Perception of Hospice and Palliative Care on their Terminal Care Stress in Long-term Care Hospitals (요양병원 간호사의 죽음에 대한 태도, 호스피스완화의료인식이 임종간호 스트레스에 미치는 영향)

  • Song, Yeon Ju;Kim, Kyung Ah
    • Journal of Korean Academic Society of Home Health Care Nursing
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    • v.28 no.3
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    • pp.256-265
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    • 2021
  • Purpose: This study examined the effects of nurses' attitude toward death and their perception of hospice and palliative care on their terminal care stress in long-term care hospitals (LCHs). Methods: Participants included 127 nurses from 6 Incheon LCHs. Data were collected between July and August, 2020. Self-report questionnaires were administered to collect data on their general characteristics, terminal care stress, attitude toward death, and perception of hospice and palliative care. Data analysis included descriptive statistics, independent t-test, one-way ANOVA, Pearson's correlation coefficient, and stepwise multiple linear regression using the SPSS 23.0 statistical program. Results: Nurses' terminal care stress was affected by their attitude toward death (𝛽=.30, p<.001) and perception of hospice and palliative care (𝛽=.28, p=.002) with an explanatory power of 21.6%. Conclusion: Terminal care stress was significantly associated with their attitude toward death and perception of hospice and palliative care. Therefore, educating nurses in LCHs about death and hospice and palliative care is essential to manage their terminal care stress effectively.

Searching of Biomechanical Determination Factor for Improving Club Head Speed during the Driver Swing in Male Golf Players (남자 골프선수의 드라이버 스윙 시 클럽 헤드 스피드 향상을 위한 운동역학적 결정요인 탐색)

  • Jae-Woo Lee;Young-Suk Kim;Jun-Sung Park
    • Korean Journal of Applied Biomechanics
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    • v.34 no.1
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    • pp.1-8
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    • 2024
  • Objective: The aim of this study was to identify the biomechanical determination factor for improving club head speed during the driver swing in male golf players. Method: Twenty-seven golf players were participated in this study. Eight motion capture cameras (250 Hz) and two force plates (2,000 Hz) were used to collect peak angular velocity and ground reaction force data. It was performed stepwise multiple linear regression analysis and alpha set at .05. Results: The peak plantar flexion angular velocity of the left ankle joint and the peak adduction angular velocity of the right shoulder joint were statistically significant. The peak plantar flexion angular velocity of the left ankle joint and the peak adduction angular velocity of the right shoulder during downswing. Conclusion: It is suggested that applying body conditioning training aimed at improving related body functions to increase maximum plantar flexion angular velocity in the left ankle joint will be effective in improving club head speed.