• Journal of The Korean Association For Science Education
• /
• v.37 no.5
• /
• pp.835-846
• /
• 2017

The purpose of this study is to investigate the perceptions of scientifically gifted middle school students about their engineering design process according to gender and talent division. The instrument in surveying their perceptions about the engineering design process consists of 24 items (Likert 5 point type) five domains: problem definition, information collection and utilization, idea generation, inquiry performance, and teamwork (communication, cooperation, leadership). A total of 102 scientifically gifted students participated in the survey, according to gender (69 males and 33 females) and talent divisions (physics, biological sciences, software, mathematics, space-geological sciences, and chemistry). They had a high level of awareness of their engineering design ability. It is necessary to develop a customized gifted-education program so that their talent in their field of interest can be fully displayed according to the gender and talent division. In addition, the teaching and learning methods and strategies of the engineering design program for the scientifically gifted middle school students should be established to fully reflect the practical needs of the talented.

• Journal of Gifted/Talented Education
• /
• v.25 no.6
• /
• pp.971-987
• /
• 2015

This paper aims at analyzing SW club acitivities on the science core high school using information disclosure. Targeting 103 schools across the nation science core high schools, the factors influencing the SW Club was analyzed. And science core high school education plans, business plans and management reports were analyzed in SW club activities. It was the most influencing on the SW club in Creative-Experiential activities organization of computer courses. So computer curriculum reform is urgently needed. SW extra subject activities and funding was having a positive effect. Tuition reimbursement rates was having a negative effect. But academic achievement did not significantly affect. Therefore as many students as possible should be able to assist the SW extra subject activities. And it is required Programs and budget support that reflect the characteristics of local and school. Also, as science core high schools have STEAM education, science, mathematics and technology home economics teachers etc were leading the SW club activities by fusing the their curriculum and SW education. As these activities are consistent with the purpose of SW education, research should be more active autonomic consisting of various teachers.

• Education of Primary School Mathematics
• /
• v.16 no.2
• /
• pp.107-122
• /
• 2013

The purpose of the study is finding the effective teaching and learning methods on the concepts of figures through exploring the change of students' cognitive structures before and after the peer teaching activities. The difference of the peer teacher's and student's cognitive structures was investigated for the activities. Three teams, six students of 5th grade, were selected from the S elementary school in Boyeon. To figure out the students' cognitive structures, pre and post in-depth interviews were conducted and analyzed. Both peer teachers' and learners' cognitive structures were changed. Peer teachers' cognitive structures were changed more positively than peer learners. A consistent systematic planation and continuous teacher support and effort are needed for the activities.

• Journal of the Korea Convergence Society
• /
• v.8 no.6
• /
• pp.209-218
• /
• 2017

Flipped Learning is being suggested which is well known as a teaching method which lets students learn the contents they will learn in advance through the advance online video and have a discussion through the team interaction in the main class for them to solve the assignment through the cooperation in a self-initiated way. Therefore, this study was intended to confirm if the flipped learning class could improve the students' learning ability and raising the interest in math by complementing the problem on the lecture-type class by applying the flipped learning class to the college basic math subject. As a result, in the unit test result, the average score of the experimental group was more than 20 higher than one of the control group indicating that Flipped Learning had a great effect on improving the learning ability, and as for the introspection journal analysis, many subjects from the experimental group showed the positive attitude toward math they felt difficult unlike ones from control group indicating that it was effective in improving the interest level.

• Journal of Communications and Networks
• /
• v.15 no.1
• /
• pp.77-86
• /
• 2013

Cognitive radio (CR) has emerged as one of effective methods to enhance the utilization of existing radio spectrum. Main principle of CR is that secondary users (SUs) are allowed to use the spectrum unused by primary users (PUs) without interfering PU's transmissions. In this paper, PUs operate on a slot-by-slot basis and SUs try to exploit the slots unused by PUs. We propose OSA protocols in the single channel and we propose an opportunistic spectrum access (OSA) protocols in the multi-channel cognitive radio networks with one control channel and several licensed channels where a slot is divided into contention phase and transmission phase. A slot is divided into reporting phase, contention phase and transmission phase. The reporting phase plays a role of finding idle channels unused by PUs and the contention phase plays a role of selecting a SU who will send packets in the data transmission phase. One SU is selected by carrier sense multiple access / collision avoidance (CSMA/CA) with request to send / clear to send (RTS/CTS) mechanism on control channel and the SU is allowed to occupy all remaining part of all idle channels during the current slot. For mathematical analysis, first we deal with the single-channel case and we model the proposed OSA media access control (MAC) protocol by three-dimensional discrete time Markov chain (DTMC) whose one-step transition probability matrix has a special structure so as to apply the censored Markov chain method to obtain the steady state distribution.We obtain the throughput and the distribution of access delay. Next we deal with the multi-channel case and obtain the throughput and the distribution of access delay by using results of single-channel case. In numerical results, our mathematical analysis is verified by simulations and we give numerical results on throughput and access delay of the proposed MAC protocol. Finally, we find the maximum allowable number of SUs satisfying the requirements on throughput and access delay.

• Journal of the Korean Data and Information Science Society
• /
• v.23 no.2
• /
• pp.247-256
• /
• 2012

Recently, estimation of greenhouse gas (GHG) emission has continuously emerged as an important global issue. This study compares various statistical methods for estimation of fuel consumption, which is necessary for calculation of GHG emission in road transportation sector. Existing methods have focused on using merely transportation fuel supply or distance traveled for calculation of fuel consumption. Estimates of GHG emission based on fuel supply, however, cannot reflect various vehicle types or model year. This study suggests and compares, from statistical point of view, several methods, which can be applied to estimate fuel consumption of each vehicle, by combining distance traveled and fuel efficiency (mileage), and total fuel consumption of all vehicles. It also suggests practical measures that can reflect vehicle types and model year to suggested methods for future research.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.6
• /
• pp.1315-1331
• /
• 2014

Replacement rates which shows the ratio of retirement income relative to preretirement income is used for a valuable evaluation measures while discussing social security benefit levels or the adequacy of retirement income. However, replacement rates has been only used for an index for evaluating benefit level at the time of retirement or specific retirement period in advanced research projects. This article analyzes how much the uncertainty of survival has an influence on retirement income, and shows replacement rates in conformity with the period of survival as an index. The researchers named this index lifetime income replacement rates. Analysis based on this index shows both life replacement income rates of 38.3% in men's case and of 41.1% in women's case while enrolled for 20years in three pension plans - national pension, retirement pension and individual annuity.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.2875-2882
• /
• 2013

The design of PN(Pseudo Noise) sequences with good cross-correlation properties is important for many research areas in communication systems. Also analyses of cross-correlation frequency between designed sequences have been researched. In this paper we analyze of cross-correlation distribution and properties of non-linear binary sequences family $S^r=\{Tr^m_1\{[Tr^n_m(a{\alpha}^t+{\alpha}^{dt}]^r\}{\mid}a{\in}GF(2^m),0{\leq}t < 2^n-1\}$, where $gcd(r,2^m-1)=1$ with 5-valued cross-correlation.

• The Korean Journal of Applied Statistics
• /
• v.28 no.1
• /
• pp.9-21
• /
• 2015

The support vector machine has been successfully applied to various classification areas due to its flexibility and a high level of classification accuracy. However, when analyzing imbalanced data with uneven class sizes, the classification accuracy of SVM may drop significantly in predicting minority class because the SVM classifiers are undesirably biased toward the majority class. The weighted $L_2$-norm SVM was developed for the analysis of imbalanced data; however, it cannot identify irrelevant input variables due to the characteristics of the ridge penalty. Therefore, we propose the weighted $L_1$-norm SVM, which uses lasso penalty to select important input variables and weights to differentiate the misclassification of data points between classes. We demonstrate the satisfactory performance of the proposed method through simulation studies and a real data analysis.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.31 no.5
• /
• pp.247-254
• /
• 2017

The meridian theory(經絡學說) is one of the important Korean medical theories distinguishing it from western medicine. The meridian theory(經絡學說) can be divided broadly into meridians(經脈) and collaterals(絡脈). The studies on meridians(經脈) have been relatively advanced, but the studies on the collaterals(絡脈) has not been enough progressed so far. Fifteen main collaterals(十五絡脈) are the biggest and most important part of collaterals(絡脈). Unlike other collateral(絡脈), fifteen main collaterals(十五絡脈) have certain routes and their own collateral acupoints(絡穴). So we studied the structure of collateral(絡脈) mainly on fifteen main collaterals(十五絡脈). In addition, we searched the Asian symbolic-mathematical(象數學的) meaning of the fifteen main collaterals(十五絡脈) and newly described them. As a result, the concept of collaterals(絡脈) has been created by the accumulation of clinical experience later than that of meridians(經脈), and it has been formed while the meridian theory(經絡學說) were developed. The meaning of 'fifteen' in fifteen main collaterals(十五絡脈) could be analysed in three ways based on the result of symbolic-mathematical(象數 學的) study. According to those results, we could find that the structure of fifteen main collaterals(十五絡脈) in "Internal Classic(內經)" was accurate.