• 한국과학교육학회지
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• 제27권3호
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• pp.212-224
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• 2007

물질대사는 생명 현상을 이해하는데 중추적 위치를 차지하고 있지만, 개념의 추상적 성격으로 인해 학생들이 이해하기 어려운 내용으로 알려져 있다. 이 연구의 목적은 (1) 효소 반응 실험의 결과 해석 과정에서 체계적 비유를 적용한 후에 나타난 학생의 개념 변화를 알아보고, (2) 학생들의 개념 변화에 기여한 체계적 비유의 역할을 확인하며, (3) 개념의 존재론적 속성에 따른 학생들의 개념 이해 정도 차이를 알아보는 것이다. 이러한 연구 목적을 위해 중학교 과학영재 34명을 대상으로 실시한 사전검사와 사후검사 결과, 실험보고서 내용, 수업 후에 뚜렷한 개념 변화를 보인 4명의 학생들을 대상으로 한 면담 결과 등의 자료를 수집하여 분석하였다. 그 결과 수업 후에 활성화 에너지 감소에 의한 효소 반응 촉진 기능 이해, 효소 구조에 따른 반응 속도 변화 이해, 효소 작용 기작에 대한 이해 정도가 전반적으로 향상되었지만, 개념의 존재론적 속성에 따라 학생의 이해 정도에 차이가 있는 것으로 나타났다. 사건 범주에 속하는 효소의 기능에 대한 이해 정도는 높았지만, 평형 범주에 속하는 효소 반응 기작에 대한 이해 정도는 낮게 나타났다. 효소 개념은 이처럼 평형 범주의 속성을 가지고 있어 학생들의 이해가 어렵지만, 본 연구에서 일부 학생들이 사건 범주의 효소 개념에서 평형 범주의 효소 개념으로 변화를 보였으며, 이러한 개념 변화에 체계적 비유가 기여한 것으로 나타났다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1158-1158
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• 2001

Fast and dynamic biochemical, enzymatic and morphological changes occur during the so-called generative development and during the vegetative processes in seeds. The most characteristic biochemical and compositional changes of this period are the formation and decline of storage components or their precursors, the change of their degree in polymerization and an extensive change in water content. The aim of the present study was to detect the maturation processes in seed nondestructively and to verify the applicability of near infrared spectroscopic methods in the measurement of physiological, chemical and biochemical changes in wheat seed. The amount and variation of different water “species” has been changed intensively during maturation. Characteristic changes of three water absorption bands (1920, 1420 and 1150 nm) during maturation were analysed. It was concluded that the free/bound transition of water molecules could be followed sensitively in different region of NIR spectra. Kinetic changes of carbohydrate reserves were characteristic during maturation. An intensive formation and decline of carbohydrate reserves were observed during early stage of maturation (0 -13 days, high energy demand). An accelerated formation of storage carbohydrates (starch) was detected in the second phase of maturation. Five characteristic absorption bands were analysed which were sensitive indicators the changes of carbohydrates occurred during maturation. Precursors of protein synthesis and the synthesis of reserve proteins and their kinetic changes during maturation were followed from NIR spectra qualitative and qualitatively. Dynamic formation of amino acids and the changes of N forms were detected by spectroscopic, chromatographic and by capillary electrophoresis methods. Calibration equations were developed and validated in order to measure the optimal maturation time protein and moisture content of developing wheat seeds. The spectroscopic methods are offering chance and measurement potential in order to detect fine details of physiological processes. The spectra have many hidden details, which can help to understand the biochemical background of processes.

• 한국물환경학회지
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• 제23권6호
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• pp.843-849
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• 2007

Monitoring of NOM characteristics is important for improving removal efficiency of natural organic matter (NOM) in water treatment processes. In this study, several NOM characteristics, which include specific UV absorbance (SUVA), total carbonate content, molecular weight distribution, and fluorescence properties, were measured using samples collected from a pilot-scale water treatment plant consisting of coagulation/flocculation (C/F), filtration, ozonation and granular activated carbon (GAC) processes. The highest removal of NOM was observed in C/F and filtration processes as demonstrated by the reduction of dissolved organic carbon (DOC) by 25% and 21%, respectively. Despite nearly no change in DOC, however, the lowest SUVA value and the highest total carbohydrate content were observed in the sample from ozonation process. This indicates that non-degradable aromatic compounds become depleted and biodegradable organic compounds are enriched during the process. Comparison of synchronous fluorescence spectra of the samples showed that ozoation process increased protein-like fluorescence while it decreased fulvic-like and terrestrial humic-like fluorescence. Consistently, a slight peak of protein-like fluorescence was observed in the sample from ozonation process. The greatest change in molecular weight distributions of the samples was observed in C/F process. Comparison of size exclusion chromatogram of the samples revealed that NOM fractions with the molecular weight greater than 2000 Da were reduced by over 90% after C/F process. SUVA values and total carbohydrate content of the samples were well correlated with a ratio of protein-like fluorescence and terrestrial humic-like fluorescence intensities with the correlation coefficients of 0.99 and 0.91, respectively. This suggests that synchronous fluorescence properties of NOM could be used as useful tolls for monitoring changes of some NOM characteristics during water treatment processes.

• The Journal of Advanced Prosthodontics
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• 제12권1호
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• pp.9-14
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• 2020

PURPOSE. The aim of this study was to investigate the effect of different numbers of heat treatments applied to superstructure porcelain on optical, thermal, and phase formation properties of zirconia. MATERIALS AND METHODS. Forty zirconia specimens were prepared in the form of rectangular prism. Specimens were divided into four groups (n = 10) according to the number of firing at heating values of porcelain. Color differences and translucency parameter were measured, and X-ray diffraction (XRD) analysis and differential scanning calorimetry (DSC) were performed. Data were analyzed with analysis of variance (ANOVA). RESULTS. There were no statistically significant differences in ∆E, TP, L, a, and b value changes of the zirconia specimens as a result of repetitive firing processes (P>.05). CONCLUSION. Although additional firing processes up to 4 increase peak density in thermal analysis, additional firing processes up to 4 times can be applied safely as they do not result in a change in color and phase character of zircon frameworks.

• Communications for Statistical Applications and Methods
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• 제27권2호
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• pp.163-175
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• 2020

We consider a wide class of general weakly-dependent processes, called ψ-weak dependence, which unify almost all weak dependence structures of interest found in statistics under natural conditions on process parameters, such as mixing, association, Bernoulli shifts, and Markovian sequences. For detecting the tail behavior of the weakly dependent processes, change point tests are developed by means of cumulative sum (CUSUM) statistics with the empirical distribution functions of sample extremes. The null limiting distribution is established as a Brownian bridge. Its proof is based on the ψ-weak dependence structure and the existence of the phantom distribution function of stationary weakly-dependent processes. A Monte-Carlo study is conducted to see the performance of sizes and powers of the CUSUM tests in GARCH(1, 1) models; in addition, real data applications are given with log-returns of financial data such as the Korean stock price index.

• 한국군사과학기술학회지
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• 제3권1호
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• pp.231-236
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• 2000

The wall thickness of the Ti-6Al-4V Large-Diameter Seamless Tube, which is supposed to be a very important parameter in a system design, was measured during $360^{\circ}$ cold bending processes. The factors or processes affecting the wall thickness include 1) primary bending, 2)secondary or finishing step of the $360^{\circ}$ bending, 3)cleaning processes in CERO TRUTM(CT)process. But thinning effects of the wall thickness during the cleaning processes are negligible compared to those during the formers. The variations in the percentages of the change in wall thickness were found to be from -14% to +16%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.234.1-234.1
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• 2014

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance[ECR], Inductively Coupled Plasma[ICP], Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. Among them, Some researchers have been studied on multiple sources In this study, we attempted to determine the possibility of multiple inductively coupled plasma (ICP), and helicon plasma sources for large-area processes. Experiments were performed with the one and two coils to measure plasma and electrical parameters, and a circuit simulation was performed to measure the current at each coil in the 2-coil experiment. Based on the result, we could determine the possibility of multiple ICP sources due to a direct change of impedance due to current and saturation of impedance due to the skin-depth effect. However, a helicon plasma source is difficult to adapt to the multiple sources due to the consistent change of real impedance due to mode transition and the low uniformity of the B-field confinement. As a result, it is expected that ICP can be adapted to multiple source for large-area processes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.389-392
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• 1999

Fatigue is a process of progressive permanent internal structural change in a material subjected to repeitive stresses. These change may be damaging and result in progressive growth of cracks and complete fracture if the stress repetitins are sufficiently large. For structural members subjected to cyclic loads, the continuous and irrecoverable damage processes are taking place. These processes are referred as the cumulative damage processes due to fatigue loading. Moreover, increased use of high strength concrete makes the fatigue problem more important because the cross-section and dead weight are reduced by using high strength concrete. The purpose of this study is to investigate the shear fatigue behavior of reinforced concrete beams according to shear reinforcement ratio and concrete compressive strength under repeated loadings. For this purpose, comprehensive static and fatigue tests of reinforced concrete beams were conducted. The major test variables for the fatigue teats are the concrete strength and the amount of shear reinforcements. The increase of deflections and steel strains according to load repetition has been plotted and analyzed to explore the damage accumulation phenomena of reinforced concrete beams. An analytical model for shear fatigue behavior has been introduced to analyze the damage accumulation under fatigue loads. The failure mode and fatigue lives have been also studied in the present study. The comparisons between analytical results and experimental data show good correlation.

• 한국IT서비스학회지
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• 제15권4호
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• pp.175-191
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• 2016

This paper investigates changing processes of new product development (NPD) systems. In order to continuously develop first-class products, world wide super-class products and hit products, R&D (Research & Development) must be competitive. Firms must achieve competitiveness in terms of quality and cost by launching new products. Most films focus on improving effectiveness and efficiency of NPD process. However, sometimes, they face to the critical challenge of transforming NPD processes entirely reflecting dramatic change of their core products. Transforming of NPD process is difficult in that it involves technological and organizational changes in marketing, R&D, Engineering and manufacturing systems. The purpose of this paper is to shed light on processes and factors affecting successful transformation of new product development systems. We present a case study on the changing processes of S company's NPD process. S company has changed new product development systems successfully from a major IT equipment supplier to an automotive supplier. Empirical results show successful changes of 10 core NPD processes from understanding the market and customers process to after sales process. In case of transformation of NPD, adaption of attribute of business is crucial for success factors in the process innovation. This paper shows the bridging the gap between IT and automotive industrial dynamics and growth through adaption of two processes in the NPD.

• 한국IT서비스학회지
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• 제5권1호
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• pp.17-34
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• 2006

As insurers have undergone changing customer expectations, increased cross-industry competition and restructured distribution channels, they need to enhance customer relationships, cut costs, increase agility and streamline operations while differentiating the core competency. As such, the importance of e-business transformation has increased where organizational core processes are restructured around customers and interned-based technology is adopted for flexible and adaptive information systems. This paper presents a case study of process innovation for e-business transformation in a Korea-based leading property & casualty insurance company. The company initiated three years-long e-business transformation program to remain competitive and to keep sustainable growth under risky and down economy. The program, which covered enterprise-wide business processes such as product, marketing & sales, customer, claim, investment & loan, accountings, etc., included redesigning processes from customers' viewpoint and then implementing process-aligned information systems. Leadership, sponsorship, change management, performance measurement, business and IT alignment, empowerment, and customized methodology, were emphasized throughout the program. As a result, the company could expect not only improvements in customer-centricity, sales productivity, and operational excellence but also increased revenues and profits in the next three years. The presented case addresses a feasible approach for enterprise-wide e-business transformation. Although the strategies, actions, and business and IT models are not described in detail due to confidentiality, the methodology and the success factors would be applicable to other insurers and possibly organizations in different industries.