• Title/Summary/Keyword: Scale Factor Stability

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Development of Korea Family Strengths Scale(KFSS-II) (한국형 가족건강성척도 II (KFSS-II) 개발 연구)

  • Yoo, Youngju;Lee, Insoo;Kim, Sunki;Choi, Heejin
    • Journal of Families and Better Life
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    • v.31 no.4
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    • pp.113-129
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    • 2013
  • The purpose of this study was to develop and validate the Korea Family Strengths Scale II (KFSS-II) which was modified and developed by Yoo(2004). For this purpose, the preliminary scale of family strengths which was based on Yoo(2004)'s sample survey that targeted 494 adults who live in Korea consisted of 30 items. Exploratory factor analysis of 29 items extracted 5 factors. It included the 5 dimensional constructs of family resilience, valuing each other & acceptance, qualitative bonding, economic stability and cooperation and caring about community. Confirmatory factor analysis confirmed the stepwise 5-factor model of 22 items considering family strengths. These results indicated that the simple template of Family Strengths Scale would be a concise and reliable tool for assessing and evaluating a family's strengths.

Experimental study of combustion stability assesment of injector (액체로켓엔진 안정성 예측을 위한 시험적 기법 연구)

  • Lee, Kwang-Jin;Seo, Seong-Hyeon;Moon, Il-Yoon;Han, Yeoung-Min;Seol, Woo-Seok;Lee, Soo-Yong
    • 한국연소학회:학술대회논문집
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    • 2003.12a
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    • pp.145-152
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    • 2003
  • The objective of the present study is to develop methodology for the assesment of combustion stability of liquid rocket injectors. To simulate actual combustion occurring inside of a thrust chamber, a full-scale injector has been employed in the study, which burns gaseous oxygen and mixture of methane and propane. The main idea of the experiment is that the mixing mechanism is considered as a dominant factor significantly affecting combustion instability in a full-scale thrust chamber. Single & multi split triplet injectors have been used with an open-end cylindrical combustion chamber. The characteristics revealed by excited dynamic pressures in gaseous combustion show degrees of relative acoustic damping depending on operating conditions. Upon test results, the direct comparison between various types of injectors can be realized for the selection of the best design among prospective injectors.

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Combustion stability assessment of muti-injector using simulant propellant in LRE (모의 추진제를 이용한 액체로켓엔진용 다중 분사기의 연소안정성 평가 방법)

  • Seo Seonghyeon;Song Joo-Young;Seol Woo-Seok;Lee Kwang-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.229-234
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    • 2004
  • The objective of the present study is to conduct model combustion tests for double swirl coaxial injectors to identify their combustion stability characteristics. Gaseous oxygen and mixture of methane and propane have been used as simulant propellants. Two model chambers tuned to the If acoustic resonance mode of a full-scale thrust chamber were manufactured to be used as a combustion cylinder. The main idea of the experiment is that the mixing mechanism is considered as a dominant factor significantly affecting combustion instability in a full-scale thrust chamber. Self-excited dynamic pressure values in a model chamber show different combustion stability zones with respect to a recess number. Upon test results, couplings between combustion conditions and the IT acoustic resonance mode become strengthened with the increase of a recess length.

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Nonlocal nonlinear stability of higher-order porous beams via Chebyshev-Ritz method

  • Ahmed, Ridha A.;Mustafa, Nader M.;Faleh, Nadhim M.;Fenjan, Raad M.
    • Structural Engineering and Mechanics
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    • v.76 no.3
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    • pp.413-420
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    • 2020
  • Considering inverse cotangential shear strain function, the present paper studies nonlinear stability of nonlocal higher-order refined beams made of metal foams based on Chebyshev-Ritz method. Based on inverse cotangential beam model, it is feasible to incorporate shear deformations needless of shear correction factor. Metal foam is supposed to contain different distributions of pores across the beam thickness. Also, presented Chebyshev-Ritz method can provide a unified solution for considering various boundary conditions based on simply-supported and clamped edges. Nonlinear effects have been included based upon von-karman's assumption and nonlinear elastic foundation. The buckling curves are shown to be affected by pore distribution, geometric imperfection of the beam, nonlocal scale factor, foundation and geometrical factors.

Reliability and Validity of the Malay Version of the Breast-Impact of Treatment Scale (MVBITS) in Breast Cancer Women undergoing Chemotherapy

  • Zainal, Nor Zuraida;Shuib, Norley;Bustam, Anita Zarina;Sabki, Zuraida Ahmad;Guan, Ng Chong
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.463-468
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    • 2013
  • Background: Body image dissatisfaction among breast cancer survivors has been associated with psychological stress resultant from breast cancer and resultant surgery. This study aimed to examine the psychometric properties of the Malay Version of the Breast-Impact of Treatment Scale (MVBITS) and to investigate the associations of retained factors with the Hospital Anxiety and Depression Scale (HADS) and the Rosenberg Self-Esteem Scale (RSES). Materials and Methods: The MVBITS was 'forward-backward' translated from English to Malay and then administered to 70 female breast cancer patients who came to the Oncology Clinic of University Malaya Medical Centre, Kuala Lumpur, Malaysia to undergo chemotherapy. Principal component analysis (PCA) with varimax rotation was performed to explore the factor structure of the MVBITS. Associations of retained factors were estimated with reference to Spearman correlation coefficients. Results: The internal consistency reliability of MVBITS was good (Cronbach's alpha 0.945) and showed temporal stability over a 3-week period. Principal component analysis suggested two factors termed as 'Intrusion' and 'Avoidance' domains. These factors explained 70.3% of the variance. Factor 1 comprised the effects of breast cancer treatment on the emotion and thought, while Factor 2 informed attempts to limit exposure of the body to self or others. The Factor 1 of MVBITS was positively correlated with total, depression and anxiety sub-scores of HADS. Factor 2 was positively correlated with total and anxiety sub-scores of HADS. MVBITS was also positively correlated with the RSES scores. Conclusions: The results showed that the Malay Version of Breast-Impact of Treatment Scale possesses satisfactory psychometric properties suggesting that this instrument is appropriate for assessment of body change stress among female breast cancer patients in Malaysia.

Development of Premarital Preparation Evaluation Scale (결혼준비도 척도 개발 연구-기혼 남.녀를 중심으로)

  • 김혜선;신수아
    • Journal of the Korean Home Economics Association
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    • v.40 no.3
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    • pp.41-53
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    • 2002
  • The purpose of this study was to develop a scale for evaluation of premarital preparation. The subjects were 412 married couples(196 males and 216 females) who had been married for 1-37ears. They were selected from Seoul, Incheon, Daejeon, Gwangju, Pusan, and DaeGu. The questionnaire was composed of 82 items. The data was analyzed by frequencies, percentages, factor analysis, Pearson's r, and Cronbach'$\alpha$. The major findings were as followings; 1. The 54 items of 82 items scale were selected through item discriminant method. The discriminant coefficients of the items(Cromer's V ranged from .33 to .68. 2. The 7 factors that were extracted from the factor analysis explained 42% of premarital preparation. The subscales were labelled as rearing child$.$financial management role division, maturity, understanding each other$.$love$.$sex, views about marriage, understanding his/her family and friends, capacity of communication and conflict resolution, and independence from parents. The criterion validity of this scale was assessed by the correlation between this premarital preparation scale and marital stability. All coefficients were significant(ranged from r=.10 to .44, p<.01, p<.001). 3. The internal consistency of this scale was acceptable(Cronbach's $\alpha$=.91).

Landing Stability Simulation of a 1/6 Lunar Module with Aluminum Honeycomb Dampers

  • Pham, Van Lai;Zhao, Jun;Goo, Nam Seo;Lim, Jae Hyuk;Hwang, Do-Soon;Park, Jung Sun
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.4
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    • pp.356-368
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    • 2013
  • The Korea Aerospace Research Institute plans to launch a lunar module by 2025, and so is carrying out a preliminary study. Landing stability on the lunar surface is a key design factor of a lunar module. In this paper, a 1/6 scale model of a lunar module is investigated, for its landing stability on non-level surfaces. The lunar module has four tripod legs, with aluminum honeycomb shock absorbers in each leg strut. ADAMS$^{TM}$, the most widely used multi-body dynamics and motion analysis software, is used to simulate the module's lunar landing. Three types of dampers in the struts (rigid, viscous, and aluminum honeycomb dampers), and two types of lunar surfaces (rigid and elastic) are considered. The Sforce function is adopted, to model the aluminum honeycomb dampers. Details on the modeling and analysis of the landing stability of the 1/6 scale lunar module and the simulation results are provided in this paper.

The Development and Validity of a Scale for Measuring Mother's Reaction to Children's Negative Emotions (아동의 부정적 정서표현에 대한 어머니 반응 척도 개발과 타당화)

  • Oh, Ji Hyun
    • Korean Journal of Child Studies
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    • v.34 no.6
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    • pp.97-122
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    • 2013
  • The aim of this study was to develop and validate measures of a mother's reaction to children's negative emotions. After construct factors of a mother's reaction to children's negative emotions based on the theoretical basis and existing scales were explored, the first preliminary items were extracted. After the content validity was confirmed by expert opinions, the second preliminary items were composed, and the initial survey was carried out. Using exploratory factor analysis, three principal factors and 21 items were revealed to be most suitable. The factors of the scale consist of emotion-coaching-reactions, oversensitive reactions, and emotion-minimizing-reactions, respectively. In addition, the reliability analysis and validation analysis of the scale was conducted, by means of surveying 413 elementary students. The internal coherence reliability and test-retest reliability were verified as was the general internal coherence and timing stability of the scale. There were three additional verifications to validate the scale. (1)For the evidence based on internal structure, the confirmatory factor analysis and convergent-discriminant evidence; this resulted in confirming the factor structure of the scale as being reliable. (2)In order to understand the relationships to other variables, the correlation analysis came in effect to the overall scale and each of its sub-factors, showing that they are significantly correlated with the scale of the child's perception on rearing attitudes of the mother. (3)As for evidence based on the consequences of the test, the correlation analysis produced a result showed that sub-factors of the scale have as significant correlation with the child's emotional intelligence and resilience.

Applications of Eigen-Sensitivity for Contingency Screening of Transient Stability in Large Scale Power Systems (대규모 전력계통의 과도안정도 상정사고 선택에 고유치감도 응용)

  • Shim, Kwan-Shik;Nam, Hae-Kon;Kim, Yong-Ku;Song, Sung-Geun
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.193-196
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    • 1999
  • This paper presents a new systematic contingency selection and screening method for transient stability. The variation of modal synchronizing torque coefficient(MSTC) is computed using eigen-sensitivity analysis of the electromechanical oscillation modes in small signal stability model and contingencies are ranked in decreasing order of the sensitivities of the MSTC(SMSTC). The relevant clusters are identified using the eigenvector or participating factor. The proposed algorithm is tested on the KEPCO system. Ranking obtained by the SMSTC is consistent with the time simulation results by PSS/E.

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Large-Scale Slope Stability Analysis Using Climate Change Scenario (2): Analysis of Application Results (기후변화 시나리오를 이용한 광역 사면안정 해석(2): 결과분석)

  • Oh, Sung-Ryul;Lee, Gi-Ha;Choi, Byoung-Seub;Lee, Kun-Hyuk;Kwon, Hyun-Han
    • Journal of the Korean Association of Geographic Information Studies
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    • v.17 no.3
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    • pp.1-19
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    • 2014
  • This study aims to assess the slope stability variation of Jeonbuk drainage areas by RCM model outputs based on A1B climate change scenario and infinite slope stability model based on the previous research by Choi et al.(2013). For a large-scale slope stability analysis, we developed a GIS-based database regarding topographic, geologic and forestry parameters and also calculated daily maximum rainfall for the study period(1971~2100). Then, we assess slope stability variation of the 20 sub-catchments of Jeonbuk under the climate change scenario. The results show that the areal-average value of safety factor was estimated at 1.36(moderately stable) in spite of annual rainfall increase in the future. In addition, 7 sub-catchments became worse and 5 sub-catchments became better than the present period(1971~2000) in terms of safety factor in the future.