• 한국수학교육학회지시리즈C:초등수학교육
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• 제25권3호
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• pp.251-278
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• 2022

본 연구의 목적은 한국, 일본, 싱가포르, 핀란드의 초등 수학교과서의 소수의 곱셈과 나눗셈에 대하여 어떻게 제시하고 있는지 분석하여 수학교육을 위한 시사점을 얻고자 하는 것이다. 소수의 곱셈과 나눗셈은 학생들이 자주 오개념을 가지는 것에 비하여 이를 표현하는 최근 초등 수학교과서의 비교 연구는 많지 않았다. 이 연구를 위하여 한국의 초등 수학교과서와 TIMSS나 PISA와 같은 국제성취도 연구에서 높은 수학 성취도를 나타내는 일본, 싱가포르, 핀란드에서 널리 사용하는 초등 수학교과서를 선정하였다. 분석은 소수의 곱셈과 나눗셈과 관련한 초등 수학과 교육과정, 지도 시기와 내용, 실생활 소재, 시각적 모델의 사용, 알고리즘의 형식화 방법의 관점에서 살펴보았다. 연구 결과, 소수의 곱셈과 나눗셈 관련 수학과 교육과정은 한국과 핀란드의 경우 어림을 포함하고, 일본과 싱가포르는 실생활 연계를 보다 강조하며 핀란드는 중등에서 연산이 완성되도록 하고 있다. 지도 시기와 내용은 짧은 기간에 집중적으로 지도하거나 여러 학년과 학기에 분산하기도 한다. 실생활의 소재는 모든 나라에서 간단한 문장제 형식으로 제시하였고, 시각적 모델의 사용이나 알고리즘의 형식화 방법은 단위 환산 등에서 자연수의 연산과 연계하도록 한다. 이러한 분석을 통해 교과서 개발 및 교사 연수에 제안을 하였다.

• Journal of Periodontal and Implant Science
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• 제54권2호
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• pp.75-84
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• 2024

Purpose: This study investigated the relationship between the number of days that hospital visits were postponed and changes in clinical parameters due to the spread of coronavirus disease 2019 (COVID-19), after the Japanese government declared a state of emergency in April 2020. Methods: Regarding the status of postponement of appointments, we analyzed the patients who had visited the Nihon University Hospital at Matsudo for more than 1 year for supportive periodontal therapy (SPT) and classified them into low-, moderate- and high-risk subgroups according to the periodontal risk assessment (PRA). Clinical parameters for periodontal disease such as probing depth (PD), full-mouth bleeding score (FMBS), full-mouth plaque score, periodontal inflamed surface area (PISA), and periodontal epithelial surface area (PESA) were analyzed in 2 periods, from October 2019 to March 2020 and after April 2020. Correlation coefficients between days of deferral and the degree of changes in clinical parameters were calculated. Results: The mean age of the 749 patients was 67.56±10.85 years, and 63.82% were female. Out of 749 patients, 33.24% deferred their SPT appointments after April 2020. The average total of postponement days was 109.49±88.84. The number of postponement days was positively correlated with changes in average PD (rs=0.474) and PESA (rs=0.443) in the high-risk subgroup of FMBS, and average PD (rs=0.293) and PESA (rs=0.253) in the highrisk subgroup of tooth number (TN). Patients belonging to the high-risk subgroups for both FMBS and TN had a positive correlation between postponement days and PISA (rs=0.56). Conclusions: The findings, the spread of COVID-19 appears to have extended the visit interval for some SPT patients. Moreover, longer visit intervals were correlated with the worsening of some clinical parameters for SPT patients with high PRA.

• Structural Engineering and Mechanics
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• 제48권6호
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• pp.757-774
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• 2013

An integrated simulation tool for multilayer stepped pyramidal structures is presented. The tool, based on a semi-analytical mathematical strategy, is able to calculate the temperature distributions and thermal stresses at the interfaces between the layers of such structures. The core of the thermal solver is the analytical simulator for power electronic devices, DJOSER, which has been supplemented with a mechanical solver based on the finite-element method. To this end, a new ele-ment is proposed whose geometry is defined by its mean surface and thickness, just as in a plate. The resulting mechanical model is fully three-dimensional, in the sense that the deformability in the direction orthogonal to the mean surface is taken into account. The dedicated finite element code developed for solving the equilibrium problem of structures made up of two or more superimposed plates subjected to thermal loads is applied to some two-layer samples made of silicon and copper. Comparisons performed with the results of standard finite element analyses using a large number of brick elements reveal the soundness of the strategy employed and the accuracy of the tool developed.

• Earthquakes and Structures
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• 제12권2호
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• pp.223-236
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• 2017

Seismic assessment and rehabilitation of Monumental Buildings constitute an important issue in many regions around the world to preserve cultural heritage. On the contrary, many recent earthquakes have demonstrated the high vulnerability of this type of structures. The high nonlinear masonry behaviour requires ad hoc refined finite element numerical models, whose complexity and computational costs are generally unsuitable for practical applications. For these reasons, several authors proposed simplified numerical strategies to be used in engineering practice. However, most of these alternative methods are oversimplified being based on the assumption of in-plane behaviour of masonry walls. Moreover, they cannot be used for modelling the monumental structures for which the interaction between plane and out-plane behaviour governs the structural response. Recently, an innovative discrete-modelling approach for the simulation of both in-plane and out of-plane response of masonry structures was proposed and applied to study several typologies of historic structures. In this paper the latter model is applied with reference to a real case study, and numerically compared with an advanced finite element modelling. The method is applied to the St.Venerio church in Reggiolo (Italy), damaged during the 2012 Emilia-Romagna earthquake and numerically investigated in the literature.

• 한국자기공명학회논문지
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• 제20권4호
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• pp.129-137
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• 2016

Transmembrane(TM) proteins are closely related to transport, channel formation, signaling, cell to cell interaction, so they are the crucial target of modern medicinal drugs. In order to study the structure and function of these TM proteins, it is important to prepare reasonable amounts of proteins. However, their preparation is seriously difficult and time-consuming due to insufficient yields and low solubility of TM proteins. We tried to produce large amounts of Syndecan-4 containing TM domain(SDC4-TM) that is related to the wound healing and tumor. Also, mutated SDC4-TM was studied to investigate structural change by modification of dimerization motif. We performed the structure determination by the Polarity Index at Slanted Angle (PISA) wheel pattern analysis based on $^{15}N-^1H$ 2D SAMPI-4 solid-state NMR of SDC4-TM and computational modeling using Discovery Studio 2016.

• 한국지구과학회지
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• 제27권7호
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• pp.730-744
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• 2006

The United States curriculum reform movement has recently started in each area of science education. The initiatives on curriculum reform stem from a notion that the low rate of science curricula offered in schools has been a serious problem. The schools in the United States are not only facing a lack of offerings within science curricula but also low enrollment in science courses, especially in physics, chemistry, and earth science. This trend resulted in low performances on international achievement tests including TIMSS and PISA. This paper introduces the efforts to solve existing problems through curriculum reform; including ChemCom, BioCom, EarthComm, and Active Physics. In this paper, a discussion is presented to show how the curricula can help address the status quo in science education. More specifically, this paper focuses on curriculum reform in high school earth science (EarthComm), providing a closer look at the scope and sequence of the reform movement. EarthComm was chosen because it was released based on the development of the National Science Education Standards (NRC, 1996). Consequently, EarthComm became a curriculum that espoused the visions of the Standards, which has been guiding the reform of the US curriculum. At the end of this paper, two research outcomes of the EarthComm curriculum implementation in schools are discussed in terms of student learning and differences from conventional curricula.

• 한국수학교육학회지시리즈A:수학교육
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• 제50권1호
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• pp.89-102
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• 2011

The purpose of this study is to diagnose the problems of mathematics education in Korea by conducting an in-depth analysis of international comparative studies, a Delphi method, and a survey. Further analysis of TIMSS and PISA results also reveals several negative aspects of mathematics education practice in Korea. The mathematics education experts' opinions collected by Delphi method were classified into 12 categories: private education and test-driven education, curriculum and textbooks, lessons, evaluation, teacher, learner, teaching aid and facilities. affective aspects of mathematics, discrepancy between a theory and a practice, preservice/inservice teacher education and teacher employment test, education policy, and overall. Another survey was conducted to focus more on the development of curriculum which is a pending issue. Considering the fact that mathematics education should contribute to improve practical aspect as well as elaborate theoretical aspect, this study lays a foundation of improvement of mathematics education in Korea.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.855-870
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• 2012

The paper deals with three main topics: a) the definition of System Thermal-Hydraulics (SYS TH), b) a historical outline for SYS TH and, c) the description of elements for reflection when planning research projects or improvement activities, this last topic being the main reason for the paper. Distinctions between basic thermal-hydraulics and computational Fluid-Dynamics (CFD) on the one side and SYS TH on the other side are considered under the first topic; stakeholders in the technology are identified. The proposal of Interim Acceptance Criteria for Emergency Core Cooling Systems in 1971 by US NRC (AEC at the time) is recognized as the starting date or the triggering event for SYS TH (second topic). The complex codes and the main experimental programs (list provided in the paper) constitute the pillars for SYS TH. Caution or warning statements are introduced in advance when discussing the third topic: a single person (or a researcher) has little to no possibility, or capability, of streamlining the forthcoming investments or to propose a roadmap for future activities. Nevertheless, the ambitious attempt to foresee developments in this area has been pursued without constraints connected with the availability of funds and with industrial benefits or interests. Demonstrating the acceptability of current SYS TH limitations and training in the application of those codes are mentioned as the main challenges for forthcoming research activities.

• Computers and Concrete
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• 제12권4호
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• pp.553-563
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• 2013

The present study aims to show how the problem of reproducing, as closely as possible, binders of historic mortars by mixing raw materials which are commercially available, can be formulated as a linear optimization problem. The study points out that by mixing five standard raw materials (end-members) it is possible to obtain mortar binders with the almost same chemical compositions of those determined on the historic and archaeological mortar samples studied in some recent scientific papers. An advanced function of the Microsoft Excel spreadsheet, the Solver add-in, was used for the calculation of the right amount of each raw material to be mixed for producing the new binders. This approach could be useful to provide an optimal solution in the process of restoration of ancient monuments, where it is necessary to replace the historic mortars with new highly compatible repair mortars.

• Agribusiness and Information Management
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• 제1권2호
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• pp.43-60
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• 2009

To improve the performance of wide-issue superscalar processors, it is essential to increase the width of instruction fetch and the issue rate. Removal of control hazard has been put forward as a significant new source of instruction-level parallelism for superscalar processors and the conditional branch prediction is an important technique for improving processor performance. Branch mispredictions, however, waste a large number of cycles, inhibit out-of-order execution, and waste electric power on mis-speculated instructions. Hence, the branch predictor with higher accuracy is necessary for good processor performance. In global-history-based predictors like gshare and GAg, many mispredictions come from commit update of the branch history. Some works on this subject have discussed the need for speculative update of the history and recovery mechanisms for branch mispredictions. In this paper, we present a new mechanism for recovering the branch history after a misprediction. The proposed mechanism adds an age_counter to the original predictor and doubles the size of the branch history register. The age_counter counts the number of outstanding branches and uses it to recover the branch history register. Simulation results on the SimpleScalar 3.0/PISA tool set and the SPECINT95 benchmarks show that gshare and GAg with the proposed recovery mechanism improved the average prediction accuracy by 2.14% and 9.21%, respectively and the average IPC by 8.75% and 18.08%, respectively over the original predictor.