• Title/Summary/Keyword: inverse coefficient

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Nurses' Death Anxiety and Spirituality (간호사의 죽음불안과 영성)

  • Kim, Sook-Nam;Choi, Soon-Ock
    • The Journal of Korean Academic Society of Nursing Education
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    • v.16 no.1
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    • pp.101-110
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    • 2010
  • Purpose: This study was a descriptive research study that investigates nurses' beliefs concerning death anxiety and spirituality. Method: The subjects were 150 nurses working at general hospitals located in Busan city. Data collection was carried out from October 15 to November 30, 2008. The study used a 'Death Anxiety Scale' and a 'Korean Spirituality Scale.' The collected data was analyzed for frequency, percentage, t-test, ANOVA, and Pearson's correlation coefficient with the SPSS/WIN 17.0. Result: The level of death anxiety of the subjects averaged 3.25. In each sub-factor, 'awareness of shortness of time' was the highest at 3.57 points. Spirituality level of the subjects averaged 3.51. In each sub-factor, meaning and purpose of life was the highest at 3.70 points. In differences of death anxiety followed by general characteristics, there were significant differences according to age, and educational level. For spirituality, followed by general characteristics, there were significant differences according to age, educational level, religion, working period, and understanding about death and spirituality. There was a weak inverse correlation among fear for accidents involved with death, total spirituality level and meaning, and purpose of life. Conclusion: Future research should examine relations between nurses' death anxiety and spirituality level through random sampling and research to check psychological and social variables that influence death anxiety and spirituality. Development of a program to lessen nurses' death anxiety and to raise their spirituality level would be prudent.

Influence of the Flow Stress of the Rivet on the Numerical Prediction of the Self-Piercing Rivet (SPR) Joining (Self-Piercing Rivet 접합공정의 수치예측에 미치는 리벳 유동응력의 영향)

  • Kim, S.H.;Bae, G.;Song, J.H.;Park, K.Y.;Park, N.
    • Transactions of Materials Processing
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    • v.29 no.5
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    • pp.257-264
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    • 2020
  • This paper is concerned with the influence of the plastic property of the rivet on the numerical prediction of the Self-Piercing Rivet (SPR) Joining. In order to predict the plastic property of the rivet, a ring compression specimen was directly fabricated from the rivet used for the mechanical joining of dissimilar materials, and the FE analysis together with the ring compression test was iteratively carried out by changing the plastic property of the rivet. For reliable FE analysis, a friction coefficient was estimated based on a friction calibration curve, measuring the reductions in inner diameter and height of the ring specimen after the compression test. From each simulation result, the force-displacement curves were then compared from each other so as to obtain the rivet plastic property that shows good agreement with the experimental result. The SPR joining between GA590 1.0t and Al5052 2.0t was conducted, and the numerical prediction was performed with the use of the plastic property evaluated based on the inverse analysis and the one referred from Mori et al. [11]. Comparison of the experiment and the numerical predictions in terms of the interlock and bottom thickness revealed that the reliable evaluation of the plastic property of the rivet is necessary for the trustworthy numerical prediction of the SPR joining.

Analysis of Relationship Between LST and NDVI using Landsat TM Images on the City Areas of Jeju Island (Landsat TM 영상을 이용한 제주도 도심지역 지표면온도분포와 식생지수의 상관성 분석)

  • Quan, He-Chun;Lee, Byung-Gul
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.4
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    • pp.39-44
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    • 2009
  • To analysis the LST distribution of Jeju island, remote sensing techniques using Landsat TM band 6 data were used. In this study, we made the LST distribution map based on the NASA. The study areas are the Jeju and Seogwipo cities of the Jeju Island. And we analyzed the correlation between the LST and NDVI which was calculated from the Landsat TM band 3 and ban 4. From the result, we found that the coefficients of the correlation were -0.77 and -0.74 on the Jeju and the Seogwipo cities, respectively. Finally, from the correlation between the land cover and LST, we also found that an inverse relationship between the LST and NDVI was exist.

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Implementation of Impedance Method to Estimate Blood Flow Variation with Cuff Pressure Change (커프 압력 조절에 따른 혈류량 변화 평가를 위한 임피던스법의 구현)

  • Jeong, Do-Un;Bae, Jin-Woo;Shon, Jung-Man;Yae, Su-Yung;Choi, Byeong-Cheol;Nam, Ki-Gon;Kim, Cheol-Han;Jeon, Gye-Rok
    • Journal of Sensor Science and Technology
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    • v.13 no.6
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    • pp.462-472
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    • 2004
  • In this study, we measured the blood flow on arm by non-invasive method and implemented a system to measure variation of the blood flow by estimating bio-electrical impedance and arterial pressure according to cuff pressure. The implemented system measured impedance variation according to pressure variation applied by artificial cuff pressure on the measuring position. The system consisted of pressure measuring part and impedance measuring part using 4-electrode method. Pressure measuring part was composed of semiconductor pressure sensor and electronic circuit for signal processing of sensor output signal. In addition, impedance measuring part was composed of constant current source circuit and lock-in amplifier for detecting impedance signal. We conducted experiments of impedance measuring part using standard resistance for performance evaluation of the implemented system. In addition we experimented to estimate variation of the blood flow by measuring impedances of the experimental group. We estimated ratio of the blood flow resistance using mean arterial pressure and variation of the blood flow. As a result the ratio of the blood flow resistance and variation of blood flow were in an inverse relationship with each other and the correlation coefficient was -0.96776.

A Numerical Analysis of Gravity and Free Surface Effects on a Two-Dimensional Supercavitating Flow (2차원 초공동 유동의 중력과 자유표면 효과에 대한 수치해석)

  • Kim, Hyoung-Tae;Lee, Hyun-Bae
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.5
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    • pp.435-449
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    • 2014
  • The effects of the gravity field and the free surface on the cavity shape and the drag are investigated through a numerical analysis for the steady supercavitating flow past a simple two-dimensional body underneath the free surface. The continuity and the RANS equations are numerically solved for an incompressible fluid using a $k-{\epsilon}$ turbulence model and a mixture fluid model has been applied for calculating the multiphase flow of air, water and vapor using the method of volume of fluid and the Schnerr-Sauer cavitation model. Numerical solutions have been obtained for the supercavitating flow about a two-dimensional $30^{\circ}$ wedge in wide range of depths of submergence and inflow velocities. The results are presented for the cavity shape, especially the length and the width, and the drag of the wedge in comparison with those of the case for the infinite fluid flow neglecting the gravity and the free surface. The influences of the gravity field and the free surface on the aforementioned quantities are discussed. The length and the width of the supercavity are reduced and the centerline of the cavity rises toward the free surface due to the effects of the gravity field and the free surface. The drag coefficient of the wedge, however, is about the same except for shallow depths of submergence. As the supercavitating wedge is approaching very close to the free surface, it is found the length and the width of a cavity are shorten even though the cavitation number is reduced. Also the present result suggests that, under the influence of the gravity field and the free surface, the length of the supercavity for a certain cavitation number varies and moreover is proportional to the inverse of the submergence depth Froude number.

A Study on the Factors Affecting the Arson (방화 발생에 영향을 미치는 요인에 관한 연구)

  • Kim, Young-Chul;Bak, Woo-Sung;Lee, Su-Kyung
    • Fire Science and Engineering
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    • v.28 no.2
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    • pp.69-75
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    • 2014
  • This study derives the factors which affect the occurrence of arson from statistical data (population, economic, and social factors) by multiple regression analysis. Multiple regression analysis applies to 4 forms of functions, linear functions, semi-log functions, inverse log functions, and dual log functions. Also analysis respectively functions by using the stepwise progress which considered selection and deletion of the independent variable factors by each steps. In order to solve a problem of multiple regression analysis, autocorrelation and multicollinearity, Variance Inflation Factor (VIF) and the Durbin-Watson coefficient were considered. Through the analysis, the optimal model was determined by adjusted Rsquared which means statistical significance used determination, Adjusted R-squared of linear function is scored 0.935 (93.5%), the highest of the 4 forms of function, and so linear function is the optimal model in this study. Then interpretation to the optimal model is conducted. As a result of the analysis, the factors affecting the arson were resulted in lines, the incidence of crime (0.829), the general divorce rate (0.151), the financial autonomy rate (0.149), and the consumer price index (0.099).

Comparative Evaluation of User Similarity Weight for Improving Prediction Accuracy in Personalized Recommender System (개인화 추천 시스템의 예측 정확도 향상을 위한 사용자 유사도 가중치에 대한 비교 평가)

  • Jung Kyung-Yong;Lee Jung-Hyun
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.42 no.6
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    • pp.63-74
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    • 2005
  • In Electronic Commerce, the latest most of the personalized recommender systems have applied to the collaborative filtering technique. This method calculates the weight of similarity among users who have a similar preference degree in order to predict and recommend the item which hits to propensity of users. In this case, we commonly use Pearson Correlation Coefficient. However, this method is feasible to calculate a correlation if only there are the items that two users evaluated a preference degree in common. Accordingly, the accuracy of prediction falls. The weight of similarity can affect not only the case which predicts the item which hits to propensity of users, but also the performance of the personalized recommender system. In this study, we verify the improvement of the prediction accuracy through an experiment after observing the rule of the weight of similarity applying Vector similarity, Entropy, Inverse user frequency, and Default voting of Information Retrieval field. The result shows that the method combining the weight of similarity using the Entropy with Default voting got the most efficient performance.

Population Dynamics of Arisaema robustum (넓은잎천남성 (Arisaema robustum) 개체군의 동태)

  • 민병미;유진숙
    • The Korean Journal of Ecology
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    • v.21 no.1
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    • pp.27-33
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    • 1998
  • Arisaema robustum, which has the ability to change sex, was studied in a temperate broadleaf forest of Sanseong-ri, Joongbu-myeon, Gwangju-gun, Kyonggi Province, Korea. \ulcornerThe study, carried out from 1993 to 1997, focused on population dynamics energy budget among organs, size distribution, mortality, the relationships between sex and size, seed production and germination rate. In terms of energy budget among the organs, the ratio of aboveground to belowground biomass was 36.6 : 63.4 in non-female plants, and 81.4 : 18.6 in female plants. Also, in female plants, the ration of leaf to sexual organ biomass was 39.5 : 41.9. Therefore, the belowground ratio of female plants was lower than that of non-female plants. Plants were classified into 8 levels relative to the amount of leaf area by $100cm^2$. The rates of the smallest and the largest classes were 49% and 1%, respectively, and population distribution by size was relatively stable. The mortality averaged 13.1% per year and decreased in inverse proportion to leaf size (6.6% in the smallest and 0.0% in the largest size classes). Leaf areas were $64.1{\pm}48.5cm^2$ in non-flowering plants, $232.1{\pm}123.9cm^2$ in males and $444.8{\pm}153.9cm^2$ in females. The increase rates of leaf area per year varied from 1.9% in plants changing from female tomale, to 152.4% in plants changing from non-flowering to female. But plants which remained female for 2 years showed a decrease of 34.7%. >From this result, it is thought that the female plants invest more energy to reproduction than to vegetative organs. The correlation coefficient (CC) value between plant size and the number of seeds produced (0.55) was larger than the CC value between plant size and total seed weight (0.73). That is, the larger the plant size, the heavier the seed produced. The germination rate increased along with seed weight, and it was 95% in plants which were over 60mg fresh weight/seed.

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The Design of Polynomial RBF Neural Network by Means of Fuzzy Inference System and Its Optimization (퍼지추론 기반 다항식 RBF 뉴럴 네트워크의 설계 및 최적화)

  • Baek, Jin-Yeol;Park, Byaung-Jun;Oh, Sung-Kwun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.399-406
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    • 2009
  • In this study, Polynomial Radial Basis Function Neural Network(pRBFNN) based on Fuzzy Inference System is designed and its parameters such as learning rate, momentum coefficient, and distributed weight (width of RBF) are optimized by means of Particle Swarm Optimization. The proposed model can be expressed as three functional module that consists of condition part, conclusion part, and inference part in the viewpoint of fuzzy rule formed in 'If-then'. In the condition part of pRBFNN as a fuzzy rule, input space is partitioned by defining kernel functions (RBFs). Here, the structure of kernel functions, namely, RBF is generated from HCM clustering algorithm. We use Gaussian type and Inverse multiquadratic type as a RBF. Besides these types of RBF, Conic RBF is also proposed and used as a kernel function. Also, in order to reflect the characteristic of dataset when partitioning input space, we consider the width of RBF defined by standard deviation of dataset. In the conclusion part, the connection weights of pRBFNN are represented as a polynomial which is the extended structure of the general RBF neural network with constant as a connection weights. Finally, the output of model is decided by the fuzzy inference of the inference part of pRBFNN. In order to evaluate the proposed model, nonlinear function with 2 inputs, waster water dataset and gas furnace time series dataset are used and the results of pRBFNN are compared with some previous models. Approximation as well as generalization abilities are discussed with these results.

Measurement of Blood Flow Variation using Impedance Method (임피던스법을 이용한 혈류량 변화 측정)

  • Jeong Do-Un;Kang Seong-Chul;Jeon Gye-Rock
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2006.05a
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    • pp.693-696
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    • 2006
  • In this study, we made the system to measure variation of blood flow using bio-electrical impedance analysis method. The system, which could measure variation of impedance according to pressure change by artificial pressure, consists of pressure measurement and impedance measurement by 4-electrode method. Pressure measurement splits into semiconducting pressure sensor and electronic circuit for processing output signal. In addition, impedance measurement splits into constant current source circuit and lock-in amplifier for detection impedance signal. We experimented feature of impedance measurement using standard resistance to evaluate the system characteristic. As well as, we experimented to estimate variation of blood flow by measuring impedance and blood flow resistance ratio using mean arterial pressure and variation of blood flow with experimental group. As result of this study, blood flow resistance ratio and variation of blood flow were definitely in inverse proportion and were -0.96776 as correlation coefficient by correlation analysis.

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