• Title/Summary/Keyword: general mathematics

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Analysis of ICT literacy levels of elementary and middle school students according to their skill sets (초.중학생의 영재분야에 따른 ICT 리터러시 능력 수준 분석)

  • Lee, SeungJin;Kim, JaMee;Lee, WonGyu
    • The Journal of Korean Association of Computer Education
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    • v.16 no.2
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    • pp.69-78
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    • 2013
  • For the increasingly complicated and technology dependent 21st century, ICT literacy is being emphasized by education authorities as a key ability needed to succeed in a knowledge-based society. Accordingly, since 2007, several studies have been conducted to measure the ICT literacy levels of students. This study aimed at analyzing how ICT literacy levels vary according to students' skill sets from the viewpoint of educational convenience. To fulfill this goal, the ICT literacy abilities of 167 elementary students and 159 middle school students (all receiving education at "gifted students" education centers) were compared with the following results. First, elementary students displayed differences with regards to 'computer and network' and 'information society and ethics' among the content elements, and 'critical mind' and 'information communication' among capability elements according to their skill sets. Second, middle school students displayed differences with regards to 'information society and ethics' and 'information organization and creation' elements according to their skill sets. The significance of this study lies in the fact that it measured the ICT literacy levels of --and made suggestions for education to-- students specially gifted in information, science and mathematics rather than general students.

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Development and Students' Perceptions after Application of a Subject Substitute STEAM Program - Focusing on Energy Unit in 6th Grade Curriculum - (교과대체형 STEAM(융합인재교육) 프로그램 개발 및 적용 후 학생들의 인식 분석 - 6학년 에너지 관련 단원을 중심으로 -)

  • Lim, Sung-Man;Chae, Dong-Hyun;Kim, Eun-Jeong;Hyun, Dong-Geul;Kim, O-Beom;Han, Je-Jun
    • Journal of the Korean Society of Earth Science Education
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    • v.7 no.1
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    • pp.119-132
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    • 2014
  • In recent years, Korea encourages teachers to do STEAM education(Science, Technology, Engineering, Arts & Mathematics), which includes Arts to STEM education to train creative science technology talent. Related to this, we developed a subject substitute STEAM program for the 6th grade students in elementary school and applied it in a field. The STEAM program which substitutes contents in curriculum related to Energy unit was developed and it was taught to twenty four sixth grade students during regular classes. During the classes, all activities of students were observed and they were written in recording notes during the observation. After all STEAM program ended, how students recognize the subject substitute STEAM program compared to general class, understand learning contents and think about the program before and after the STEAM classes were analyzed through questionnaire and interviews. The results were as follows. First, some students had difficulty in reconciling different ideas in group, creative thinking and crafts but most students liked the STEAM classes because many activities are fun and it is easy to understand. Second, learners regarded practical use of knowledge, learning different subjects together and interests as the reasons they can understand learning contents easily during STEAM program. Third, learners recognized STEAM classes are good to understand knowledge, think creative ideas and improve social skills after the STEAM classes while they showed anticipation, worry and fear before taking the classes. It is found that a subjective substitute STEAM program is helpful to increase learners' interests in learning, understand learning contents, increase creativity and have a good personality through a qualitative research.

Estimation for the Variation of the Concentration of Greenhouse Gases with Modified Shannon Entropy (변형된 샤논 엔트로피식을 이용한 온실가스 농도변화량 예측)

  • Kim, Sang-Mok;Lee, Do-Haeng;Choi, Eol;Koh, Mi-Sol;Yang, Jae-Kyu
    • Journal of Environmental Science International
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    • v.22 no.11
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    • pp.1473-1479
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    • 2013
  • Entropy is a measure of disorder or uncertainty. This terminology is qualitatively used in the understanding of its correlation to pollution in the environmental area. In this research, three different entropies were defined and characterized in order to quantify the qualitative entropy previously used in the environmental science. We are dealing with newly defined distinct entropies $E_1$, $E_2$, and $E_3$ originated from Shannon entropy in the information theory, reflecting concentration of three major green house gases $CO_2$, $N_2O$ and $CH_4$ represented as the probability variables. First, $E_1$ is to evaluate the total amount of entropy from concentration difference of each green house gas with respect to three periods, due to industrial revolution, post-industrial revolution, and information revolution, respectively. Next, $E_2$ is to evaluate the entropy reflecting the increasing of the logarithm base along with the accumulated time unit. Lastly, $E_3$ is to evaluate the entropy with a fixed logarithm base by 2 depending on the time. Analytical results are as follows. $E_1$ shows the degree of prediction reliability with respect to variation of green house gases. As $E_1$ increased, the concentration variation becomes stabilized, so that it follows from linear correlation. $E_2$ is a valid indicator for the mutual comparison of those green house gases. Although $E_3$ locally varies within specific periods, it eventually follows a logarithmic curve like a similar pattern observed in thermodynamic entropy.

A Study on Intrusion Detection in Network Intrusion Detection System using SVM (SVM을 이용한 네트워크 기반 침입탐지 시스템에서 새로운 침입탐지에 관한 연구)

  • YANG, Eun-mok;Seo, Chang-Ho
    • Journal of Digital Convergence
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    • v.16 no.5
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    • pp.399-406
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    • 2018
  • Much research has been done using the KDDCup99 data set to study intrusion detection using artificial intelligence. Previous studies have shown that the performance of the SMO (SVM) algorithm is superior. However, intrusion detection studies of new intrusion types not used in training are insufficient. In this paper, a model was created using the instances of weka's SMO and KDDCup99 training data set, kddcup.data.gz. We tested existing instances(292,300) of the corrected.gz file and new intrusions(18,729). In general, intrusion labels not used in training are not tested, so new intrusion labels were changed to normal. Of the 18,729 new intrusions, 1,827 were classified as intrusions. 1,827 instances classified as new intrusions are buffer_overflow. Three, neptune. 392, portsweep. 164, ipsweep. 9, back. 511, imap. 1, satan. Dogs, 645, nmap. 102.

The effect of RBS connection on energy absorption in tall buildings with braced tube frame system

  • Shariati, Mahdi;Ghorbani, Mostafa;Naghipour, Morteza;Alinejad, Nasrollah;Toghroli, Ali
    • Steel and Composite Structures
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    • v.34 no.3
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    • pp.393-407
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    • 2020
  • The braced tube frame system, a combination of perimeter frame and bracing frame, is one of the systems used in tall buildings. Due to the implementation of this system in tall buildings and the high rigidity resulting from the use of general bracing, providing proper ductility while maintaining the strength of the structure when exposing to lateral forces is essential. Also, the high stress at the connection of the beam to the column may cause a sudden failure in the region before reaching the required ductility. The use of Reduced Beam Section connection (RBS connection) by focusing stress in a region away from beam to column connection is a suitable solution to the problem. Because of the fact that RBS connections are usually used in moment frames and not tested in tall buildings with braced tube frames, they should be investigated. Therefore, in this research, three tall buildings in height ranges of 20, 25 and 30 floors were modeled and designed by SAP2000 software, and then a frame in each building was modeled in PERFORM-3D software under two RBS-free system and RBS-based system. Nonlinear time history dynamic analysis is used for each frame under Manjil, Tabas and Northridge excitations. The results of the Comparison between RBS-free and RBS-based systems show that the RBS connections increased the absorbed energy level by reducing the stiffness and increasing the ductility in the beams and structural system. Also, by increasing the involvement of the beams in absorbing energy, the columns and braces absorb less energy.

LARGE TIME ASYMPTOTICS OF LEVY PROCESSES AND RANDOM WALKS

  • Jain, Naresh C.
    • Journal of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.583-611
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    • 1998
  • We consider a general class of real-valued Levy processes {X(t), $t\geq0$}, and obtain suitable large deviation results for the empiricals L(t, A) defined by $t^{-1}{\int^t}_01_A$(X(s)ds for t > 0 and a Borel subset A of R. These results are used to obtain the asymptotic behavior of P{Z(t) < a}, where Z(t) = $sup_{u\leqt}\midx(u)\mid$ as $t\longrightarrow\infty$, in terms of the rate function in the large deviation principle. A subclass of these processes is the Feller class: there exist nonrandom functions b(t) and a(t) > 0 such that {(X(t) - b(t))/a(t) : t > 0} is stochastically compact, i.e., each sequence has a weakly convergent subsequence with a nondegenerate limit. The stable processes are in this class, but it is much larger. We consider processes in this class for which b(t) may be taken to be zero. For any t > 0, we consider the renormalized process ${X(u\psi(t))/a(\psi(t)),u\geq0}$, where $\psi$(t) = $t(log log t)^{-1}$, and obtain large deviation probability estimates for $L_{t}(A)$ := $(log log t)^{-1}$${\int_{0}}^{loglogt}1_A$$(X(u\psi(t))/a(\psi(t)))dv$. It turns out that the upper and lower bounds are sharp and depend on the entire compact set of limit laws of {X(t)/a(t)}. The results extend to random walks in the Feller class as well. Earlier results of this nature were obtained by Donsker and Varadhan for symmetric stable processes and by Jain for random walks in the domain of attraction of a stable law.

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GENERAL FAMILIES OF CHAIN RATIO TYPE ESTIMATORS OF THE POPULATION MEAN WITH KNOWN COEFFICIENT OF VARIATION OF THE SECOND AUXILIARY VARIABLE IN TWO PHASE SAMPLING

  • Singh Housila P.;Singh Sarjinder;Kim, Jong-Min
    • Journal of the Korean Statistical Society
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    • v.35 no.4
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    • pp.377-395
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    • 2006
  • In this paper we have suggested a family of chain estimators of the population mean $\bar{Y}$ of a study variate y using two auxiliary variates in two phase (double) sampling assuming that the coefficient of variation of the second auxiliary variable is known. It is well known that chain estimators are traditionally formulated when the population mean $\bar{X}_1$ of one of the two auxiliary variables, say $x_1$, is not known but the population mean $\bar{X}_2$ of the other auxiliary variate $x_2$ is available and $x_1$ has higher degree of positive correlation with the study variate y than $x_2$ has with y, $x_2$ being closely related to $x_1$. Here the classes are constructed when the population mean $\bar{X}_1\;of\;X_1$ is not known and the coefficient of variation $C_{x2}\;of\;X_2$ is known instead of population mean $\bar{X}_2$. Asymptotic expressions for the bias and mean square error (MSE) of the suggested family have been obtained. An asymptotic optimum estimator (AOE) is also identified with its MSE formula. The optimum sample sizes of the preliminary and final samples have been derived under a linear cost function. An empirical study has been carried out to show the superiority of the constructed estimator over others.

The wage determinants of college graduates using Heckman's sample selection model (Heckman의 표본선택모형을 이용한 대졸자의 임금결정요인 분석)

  • Cho, Jangsik
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.5
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    • pp.1099-1107
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    • 2017
  • In this study, we analyzed the determinants of wages of college graduates by using the data of "2014 Graduates Occupational Mobility Survey" conducted by Korea Employment Information Service. In general, wages contain two complex pieces of information about whether an individual is employed and the size of the wage. However, in many previous researches on wage determinants, sample selection bias tends to be generated by performing linear regression analysis using only information on wage size. We used the Heckman sample selection models for analysis to overcome this problem. The main results are summarized as follows. First, the validity of the Heckman's sample selection model is statistically significant. Male is significantly higher in both job probability and wage than female. As age increases and parents' income increases, both the probability of employment and the size of wages are higher. Finally, as the university satisfaction increases and the number of certifications acquired increased, both the probability of employment and the wage tends to increase.

Fast Factorization Methods based on Elliptic Curves over Finite Fields (유한체위에서의 타원곡선을 이용한 고속 소인수분해법에 관한 연구)

  • Kim, Yong-Tae
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.10
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    • pp.1093-1100
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    • 2015
  • Since the security of RSA cryptosystem depends on the difficulty of factoring integers, it is the most important problem to factor large integers in RSA cryptosystem. The Lenstra elliptic curve factorization method(ECM) is considered a special purpose factoring algorithm as it is still the best algorithm for divisors not greatly exceeding 20 to 25 digits(64 to 83 bits or so). ECM, however, wastes most time to calculate $M{\cdot}P$ mod N and so Montgomery and Koyama both give fast methods for implementing $M{\cdot}P$ mod N. We, in this paper, further analyze Montgomery and Koyama's methods and propose an efficient algorithm which choose the optimal parameters and reduces the number of multiplications of Montgomery and Koyama's methods. Consequently, the run time of our algorithm is reduced by 20% or so than that of Montgomery and Koyama's methods.

Risk identification, assessment and monitoring design of high cutting loess slope in heavy haul railway

  • Zhang, Qian;Gao, Yang;Zhang, Hai-xia;Xu, Fei;Li, Feng
    • Structural Monitoring and Maintenance
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    • v.5 no.1
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    • pp.67-78
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    • 2018
  • The stability of cutting slope influences the safety of railway operation, and how to identify the stability of the slope quickly and determine the rational monitoring plan is a pressing problem at present. In this study, the attribute recognition model of risk assessment for high cutting slope stability in the heavy haul railway is established based on attribute mathematics theory, followed by the consequent monitoring scheme design. Firstly, based on comprehensive analysis on the risk factors of heavy haul railway loess slope, collapsibility, tectonic feature, slope shape, rainfall, vegetation conditions, train speed are selected as the indexes of the risk assessment, and the grading criteria of each index is established. Meanwhile, the weights of the assessment indexes are determined by AHP judgment matrix. Secondly, The attribute measurement functions are given to compute attribute measurement of single index and synthetic attribute, and the attribute recognition model was used to assess the risk of a typical heavy haul railway loess slope, Finally, according to the risk assessment results, the monitoring content and method of this loess slope were determined to avoid geological disasters and ensure the security of the railway infrastructure. This attribute identification- risk assessment- monitoring design mode could provide an effective way for the risk assessment and control of heavy haul railway in the loess plateau.