• Title/Summary/Keyword: prime numbers

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An Experimental Study of Accelerating Phase Change Heat Transfer

  • Oh, Yool-Kwon;Park, Seul-Hyun;Cha, Kyung-Ok
    • Journal of Mechanical Science and Technology
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    • v.15 no.12
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    • pp.1882-1891
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    • 2001
  • The present paper investigated the effect of ultrasonic vibrations on the melting process of a phase-change material (PCM). Furthermore, the present study considered constant heat flux boundary conditions unlike many of the previous researches adopted constant wall temperature conditions. Therefore, in the present study, modified dimensionless parameters such as Ste* and Ra* were used. Also, general relationships between melting with ultrasonic vibrations and melting without ultrasonic vibrations were established during the melting of PCM. Experimental observations show that the effect of ultrasonic vibrations on heat transfer is very important throughout the melting process. The results of the present study reveal that ultrasonic vibrations accompany the effects like agitation, acoustic streaming, cavitation, and oscillating fluid motion. Such effects are a prime mechanism in the overall melting process when ultrasonic vibrations are applied. They enhance the melting process as much as 2.5 tildes, compared with the result of natural melting. Also, energy can be saved by applying ultrasonic vibrations to the natural melting. In addition, various time-wise dimensionless numbers provide conclusive evidence of the important role of ultrasonic vibrations on the melting phenomena.

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A Study on the Safety Climate and Worker's Safe Work Behavior in Construction Site (건설현장의 안전 분위기와 작업자 안전행동에 관한 실증적 연구)

  • Choi, Soo-Il;Kim, Hong
    • Journal of the Korean Society of Safety
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    • v.21 no.5 s.77
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    • pp.60-71
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    • 2006
  • In recent years, the most safety studies have been focused on identifying the relationship between safety climate and safe work behavior in accordance with the awareness that prime causes of accidents are organizational, managerial, and human factors rather than pure technical failures across the world. This study focused empirical research aimed at finding out the safety climate factors and examining the relationships of the safety climate and safe work behavior in construction site in Korea, too. A 10 numbers of safety climate factors were adapted from the Mohamed's study(2002) and tested using PLS-GRAPH 3.0 expecting same results as Mohamed' study. And then the relationship between safety climate and safe work behavior was examined. Only two safety climate factors-personal risk appreciation and worker's safety competence-were found and a strong positive relationship between safety climate and safe work behavior was identified in this study. Discussed in details about the results and implications and suggested further studies.

LOCAL PERMUTATION POLYNOMIALS OVER FINITE FIELDS

  • Lee, Jung-Bok;Ko, Hyoung-June
    • Communications of the Korean Mathematical Society
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    • v.9 no.3
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    • pp.539-545
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    • 1994
  • Let $q = p^r$, where p is a prime. A polynomial $f(x) \in GF(q)[x]$ is called a permutation polynomial (PP) over GF(q) if the numbers f(a) where $a \in GF(Q)$ are a permutation of the a's. In other words, the equation f(x) = a has a unique solution in GF(q) for each $a \in GF(q)$. More generally, $f(x_1, \cdots, x_n)$ is a PP in n variables if $f(x_1,\cdots,x_n) = \alpha$ has exactly $q^{n-1}$ solutions in $GF(q)^n$ for each $\alpha \in GF(q)$. Mullen ([3], [4], [5]) has studied the concepts of local permutation polynomials (LPP's) over finite fields. A polynomial $f(x_i, x_2, \cdots, x_n) \in GF(q)[x_i, \codts,x_n]$ is called a LPP if for each i = 1,\cdots, n, f(a_i,\cdots,x_n]$ is a PP in $x_i$ for all $a_j \in GF(q), j \neq 1$.Mullen ([3],[4]) found a set of necessary and three variables over GF(q) in order that f be a LPP. As examples, there are 12 LPP's over GF(3) in two indeterminates ; $f(x_1, x_2) = a_{10}x_1 + a_{10}x_2 + a_{00}$ where $a_{10} = 1$ or 2, $a_{01} = 1$ or x, $a_{00} = 0,1$, or 2. There are 24 LPP's over GF(3) of three indeterminates ; $F(x_1, x_2, x_3) = ax_1 + bx_2 +cx_3 +d$ where a,b and c = 1 or 2, d = 0,1, or 2.

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Can We Reduce Workplace Fatalities by Half?

  • Koh, David Soo Quee
    • Safety and Health at Work
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    • v.3 no.2
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    • pp.104-109
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    • 2012
  • Singapore, an island republic of over 5 million inhabitants, has 3.1 million workers. Most are employed in the service, finance and tourist/transport industry. Significant numbers work in manufacturing, construction and heavy industry. Following a series of construction and shipyard accidents with multiple deaths in 2004, the government announced its intention to reduce workplace fatalities from 4.9 to 2.5 per 100,000 by 2015. There was strong political will to achieve this target. The strategic approaches were to build workplace safety and health (WSH) capabilities; implement legislative changes with enforcement; promote benefits of WSH and recognize best practices, and enhance partnership with stakeholders. The anticipated outcomes were to reduce workplace fatality and injury rates; have WSH as an integral part of business; and establish a progressive and pervasive WSH culture. With these measures, the workplace fatality rate declined from 4.9/100,000 in 2004, to 2.2/100,000 in 2010. However, other confounding factors could also account for this decline, and have to be considered. The next target, announced by Singapore's Prime Minister in 2008, is to further reduce the workplace fatality rate to 1.8/100,000 by 2018, and to have "one of the best workplace safety records in the world".

Relationship between Assertiveness and Attitudes toward Nurse-Physician Collaboration in General Hospital Nurses (종합병원 간호사의 자기주장과 간호사-의사의 협업에 대한 태도의 관계)

  • Lee, Sangmin;Sohn, Suekyung
    • Journal of East-West Nursing Research
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    • v.21 no.2
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    • pp.156-164
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    • 2015
  • Purpose: This study was conducted to identify the relationship of assertiveness and attitudes toward nurse-physician collaboration in general hospital nurses. Methods: The subjects were 196 clinical nurses from two general hospitals in P city. Data were collected from August 1 to 30, 2014 and analyzed by SPSS 18.0 program using descriptive statistics, t-test, ANOVA, $Sheff{\acute{e}}^{\prime}s$ test, and Pearson's correlation coefficients. Results: The mean scores of assertiveness and attitudes toward nurse-physician collaboration were $3.20{\pm}.42$ and $3.20{\pm}.30$, respectively. Assertiveness and attitudes toward nurse-physician collaboration according to the general characteristics showed significant differences on the numbers of advisors and job satisfaction. There was a significant positive correlation between assertiveness and attitudes toward nurse-physician collaboration. Conclusion: Based on results of this study, additional variables related to attitudes toward nurse-physician collaboration need to be identified. Educational programs to improve the attitudes toward nurse-physician collaboration should be developed.

ANALOGUE OF WIENER INTEGRAL IN THE SPACE OF SEQUENCES OF REAL NUMBERS

  • Ryu, Kun Sik
    • Journal of the Chungcheong Mathematical Society
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    • v.25 no.1
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    • pp.65-72
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    • 2012
  • Let T > 0 be given. Let $(C[0,T],m_{\varphi})$ be the analogue of Wiener measure space, associated with the Borel proba-bility measure ${\varphi}$ on ${\mathbb{R}}$, let $(L_{2}[0,T],\tilde{\omega})$ be the centered Gaussian measure space with the correlation operator $(-\frac{d^{2}}{dx^{2}})^{-1}$ and ${\el}_2,\;\tilde{m}$ be the abstract Wiener measure space. Let U be the space of all sequence $<c_{n}>$ in ${\el}_{2}$ such that the limit $lim_{{m}{\rightarrow}\infty}\;\frac{1}{m+1}\;\sum{^{m}}{_{n=0}}\;\sum_{k=0}^{n}\;c_{k}\;cos\;\frac{k{\pi}t}{T}$ converges uniformly on [0,T] and give a set function m such that for any Borel subset G of $\el_2$, $m(\mathcal{U}\cap\;P_{0}^{-1}\;o\;P_{0}(G))\;=\tilde{m}(P_{0}^{-1}\;o\;P_{0}(G))$. The goal of this note is to study the relationship among the measures $m_{\varphi},\;\tilde{\omega},\;\tilde{m}$ and $m$.

The correlation between the internal·external satisfaction and organizational commitment of dental hygienist (치과위생사의 내적·외적만족과 조직몰입도의 관련성)

  • Ryu, Hae-Gyum
    • Journal of Korean society of Dental Hygiene
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    • v.17 no.5
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    • pp.735-745
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    • 2017
  • Objectives: This study was conducted to provide a basic set of data on the correlation relationship between the internal external satisfaction and organizational commitment of dental hygienist. Methods: The research subjects were a total 264 numbers of dental hygienists in Busan and Gyeongnam. The study was conducted from July 1 to August 30, 2016. Structured questionnaires were used for analysis. The collected data was analyzed using IBM SPSS. Statistics 20.0. Results: Job satisfaction according to general characteristics showed high internal satisfaction and external satisfaction in age and prime duty, and internal satisfaction in career. The factors affecting organizational commitment were sub-factors of job satisfaction, external satisfaction and internal satisfaction. Conclusions: The atmosphere composition must be to improve that in the dental clinic, the dental hygienist's scope of work, autonomy, and sense of accomplishment through job the organizational commitment of the dental hygienists. This should be supported by the effective management of human resources, salary structure and the improvement of the system.

Progeny Analysis and Selection of Tomato Transformants with patII Gene linked to Inherent Disease Resistance Gene (제초제 저항성 유전자와 기존 병 저항성 유전자가 연관된 형질전환 토마토 개체 선발 및 후대분석)

  • Ahn, Soon-Young;Kang, Kwon-Kyoo;Yun, Hae-Keun;Park, Hyo-Guen
    • Horticultural Science & Technology
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    • v.29 no.4
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    • pp.345-351
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    • 2011
  • This study was carried out to develop a model system using selection method for disease resistant plant breeding programs using a herbicide bialaphos-resistant patII gene as a gene-based marker. Spraying bialaphos could eliminate the susceptible plants from the segregating populations such as ${F_2}^{\prime}s$ and thereafter. Tomato cv. Momotaro-yoke was transformed with patII gene 60 independent transformants were acquired. Total 42 transformants were analyzed in transgene copy numbers by Southern blotting and the segregation ratios for the bialaphos resistance. Statistical analysis revealed that the transgene copy numbers and the segregation ratios were not always coincided, especially having the tendency of underestimating the real numbers of the transgenes in the multicopy lines. A two-stepwise screening method was applied to select $T_1$ tomato plants which linked the transgenic patII to a disease resistance gene (I2 and Ve). Based on the resistant to susceptible ratios, T-20 plant was finally selected due to the estimated linkage 12-13 cM between the patII gene to the I2 gene on chromosome 11. This newly developed system could be applied to any economical crop in breeding programs.

The n+1 Integer Factorization Algorithm (n+1 소인수분해 알고리즘)

  • Choi, Myeong-Bok;Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.2
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    • pp.107-112
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    • 2011
  • It is very difficult to factorize composite number, $n=pq$ to integer factorization, p and q that is almost similar length of digits. Integer factorization algorithms, for the most part, find ($a,b$) that is congruence of squares ($a^2{\equiv}b^2$ (mod $n$)) with using factoring(factor base, B) and get the result, $p=GCD(a-b,n)$, $q=GCD(a+b,n)$ with taking the greatest common divisor of Euclid based on the formula $a^2-b^2=(a-b)(a+b)$. The efficiency of these algorithms hangs on finding ($a,b$) and deciding factor base, B. This paper proposes a efficient algorithm. The proposed algorithm extracts B from integer factorization with 3 digits prime numbers of $n+1$ and decides f, the combination of B. And then it obtains $x$(this is, $a=fxy$, $\sqrt{n}$ < $a$ < $\sqrt{2n}$) from integer factorization of $n-2$ and gets $y=\frac{a}{fx}$, $y_1$={1,3,7,9}. Our algorithm is much more effective in comparison with the conventional Fermat algorithm that sequentially finds $\sqrt{n}$ < $a$.

Multiplicative Thinking in Elementary Mathematics Education - Focusing on the development of teaching-learning materials for 5th graders - (초등에서의 곱셈적 사고 지도 - 초등 5학년을 위한 교수-학습 자료 개발을 중심으로 -)

  • Han, Eun-Hye;Ryu, Heui-Su
    • School Mathematics
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    • v.10 no.2
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    • pp.155-179
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    • 2008
  • Multiplication problems for the 7th curriculum focus on functional realms featuring the memorization and application of the multiplication table, exposing learners only to additive thinking characterized by simple counting and drawing. A diversity of research has yet to be conducted for the transition to multiplicative thinking that highlights the capability to solve problems by using multiplication and division in the expanded number scope like 'prime numbers', 'fractional numbers', and 'ratio/rates' and to describe accurately how they solved. This research was designed to develop and utilize teaching-learning materials for the transition of fifth graders' additive thinking to advanced multiplicative one and to analyze the application results in order to identify validity in material development. The following conclusions were made. First, the development and application of teaching-learning materials for multiplicative thinking cultivation facilitated the transition from additive thinking featuring simple counting and drawing to multiplicative thinking characterized by multiplication and accurate description in a more complicated and expanded number scope. Second, the development of materials featuring 'basic'-'intermediate'-'in-depth' courses by activity enabled learners to benefit from learning by level and expansion in number scope. Third, the use of topics and materials closely connected to daily lives stimulated learners' curiosity, helping them concentrate more on given problems. Fourth, communication between teachers and students or among learners themselves was promoted by continuously encouraging them to explain and by reviewing their documents identifying rules or patterns.

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