• Food Science and Biotechnology
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• v.18 no.6
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• pp.1342-1350
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• 2009

This paper investigates the production and optimization of $\beta$-galactosidase enzyme using synthetic medium by Kluyveromyces lactis NRRL Y-8279 in stirred tank bioreactor. Response surface methodology was used to investigate the effects of fermentation parameters on $\beta$-galactosidase enzyme production. Maximum specific enzyme activity of 4,622.7 U/g was obtained at the optimum levels of process variables (aeration rate 2.21 vvm, agitation speed 173.4 rpm, initial sugar concentration 33.8 g/L, incubation time 24.0 hr). The optimum temperature and pH of the $\beta$-galactosidase enzyme produced under optimized conditions were $37^{\circ}C$ and pH 7.0, respectively. The enzyme was stable over a pH range of 6.0-7.5 and a temperature range of $25-37^{\circ}C$. The $K_m$ and $V_{max}$ values for O-nitrophenol-$\beta$-D-galactopyranoside (ONPG) were 1.20 mM and $1,000\;{\mu}mol/min{\cdot}mg$ protein, respectively. The response surface methodology was found to be useful in optimizing and determining the interactions among process variables in $\beta$-galactosidase enzyme production. Hence, this study fulfills the lack of using mathematical and statistical techniques in optimizing the $\beta$-galactosidase enzyme production in stirred tank bioreactor.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.39-42
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• 2008

G protein-coupled receptor(GPCR) family is a cell membrane protein, and plays an important role in a signaling mechanism which transmits external signals through cell membranes into cells. Now, it is estimated that there may be about 800-1000 GPCRs in a human genome. But, GPCRs each are known to have various complex control mechanisms and very unique signaling mechanisms. GPCRs are involved in maintaining homeostasis of various human systems including an endocrine system or a neural system and thus, disorders in activity control of GPCRs are thought to be the major source of cardiovascular disorders, metabolic disorders, degenerative disorders, carcinogenesis and the like. As more than 60% of currently marketed therapeutic agents target GPCRs, the GPCR field has been actively explored in the pharmaceutical industry. Structural features, and class and subfamily of GPCRs are well known by function, and accordingly, the most fundamental work in studies identifying the previous GPCRs is to classify the GPCRs with given protein sequences. Studies for classifying previously identified GPCRs more easily with mathematical models have been mainly going on. Considering that secondary sequences of proteins, namely, secondary binding structures of amino acids constituting proteins are closely related to functions, the present paper does not place the focus on primary sequences of proteins as previously practiced, but instead, proposes a method to transform primary sequences into secondary structures and compare the secondary structures, and then detect an unknown GPCR assumed to have a same function in databases of previously identified GPCRs.

• Human Ecology Research
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• v.53 no.1
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• pp.29-47
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• 2015

The purpose of this study is to conceptualize the definition of school readiness specific to the context of the Republic of Korea. The school readiness test can be used as basic data to enable early childhood educational institutes to determine the general readiness of preschoolers and provide support to fit individual characteristics. For this purpose, six stages of the school readiness development process were considered, that is, draft development, primary preliminary survey, primary expert verification, secondary expert verification, secondary preliminary survey, and main survey. In the main survey, tests were conducted using the school readiness final draft targeting 344 preschoolers living in Seoul and Gyeonggi-do. The item discrimination power analysis and factor analysis for the examination area and question area were also conducted. Consequently, a test tool was developed on the basic of the results obtained, consisting of 129 items in the five areas of knowledge, function, adaptation, tendency, and attitude. The knowledge area was divided into general, linguistic, and mathematical knowledge, and the function area into fine motor function, basic living ability, expressive function, and gross motor function. The adaptation area was classified into adaptation activity, separation anxiety, maladaptive behavior, and environment adaptation; the tendency area into learning tendency; others understanding, and individual tendency, and the attitude area into rule compliance and life habits.

• Journal of the Korea Society of Computer and Information
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• v.8 no.1
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• pp.156-165
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• 2003

The purpose of this study is concerned with possibilistic decision making model (PDMM) that can be used to help CEO and information systems managers decide which information systems should be selected. The application of IT which has influence on rapidly changed environment of enterprise plays an important role in enterprise's activity. When enterprise outsource IT, it is very important to select vendors that reflect goals and constraints of organization. For this purpose, mathematical model in which possibilistic programming is applied is suggested in this study. Although many researches have conducted in conventional programming and stochastic programming. they are still limited in solving practical problems and imprecise/uncertain situations. Multiple decision making model in which impreciseness of input variable is considered can be constructed in PDMM.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.15-18
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• 1999

A simple mathematical model for facilitated mass transport through a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation. The current model demonstrates that the facilitation factor depends on the extent of concentration fluctuation, the time scale ratios of diffusion to chemical reaction and the ratio of the carrier concentration to the solute solubility in matrix. The model was examined against the experimental data on oxygen transport in membranes containing metallo-porphyrin carriers, and the agreement was exceptional (within 10% error). The basic concept of this approach was applied to separate olefin from olefin/paraffin mixtures. A proprietaty carrier, developed here, resulted that the selectivity of propylene over propane was more than 120 and the propylene permeance exceed 40 gpu.

• Industrial Engineering and Management Systems
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• v.9 no.4
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• pp.312-322
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• 2010

An enterprise must achieve both a sound organizational management and effective development of individual members while maintaining a balanced approach. Relative to this, there is a research field dubbed as Organizational Activation. However, there is a necessity to clarify various factors required for organizational activation and to propose a methodology for organization management. This study is an attempt to create a model from an organization-a University Seminar Class-and agents therein-the Students and the Teacher-with an assumed goal of advancing together toward the students' self-growth. The model is expressed on two dimensional planes with vectors through a computer. Vectors are composed of the growth, demand, member, hindrance and student vectors. These vectors provide data to the mathematical model for a simulation. Each agent provided the individual information from the questionnaire-conducted to 169 university students. From the analysis data and extrapolations, this study was able to craft a guideline for future seminar activity. It also examines the possibility of assimilation of the Questionnaire Approach and that of the Computational Organization Theory approach. Finally, this study discusses the future possibility of application of the Assimilated Method for research and development, and for project management.

• Journal of Electrochemical Science and Technology
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• v.13 no.3
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• pp.377-389
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• 2022

The current global energy supply depends heavily on fossil fuels. This makes technology such as direct water splitting from harvesting solar energy in photoelectrochemical (PEC) systems potentially attractive due to its a promising route for environmentally benign hydrogen production. In this study, undoped and nickel-doped molybdenum oxide photoanodes (called photoanodes S₁ and S₂ respectively) were synthesized through electrodeposition by applying -1.377 V vs Ag/AgCl (3 M KCl) for 3 hours on an FTO-coated glass substrate immersed in molibdatecitrate aqueous solutions at pH 9. Scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used for microstructural and compositional characterizations of the photoanodes. In addition, the optical and photoelectrochemical characterizations of these photoanodes were performed by UV-Visible spectroscopy, and linear scanning voltammetry (LSV) respectively. The results showed that all the photoanodes produced exhibit conductivity and catalytic properties that make them attractive for water splitting application in a photoelectrochemical cell. In this context, the photoanode S₂ exhibited better photocatalytic activity than the photoanode S₁. In addition, photoanode S₂ had the lowest optical band-gap energy value (2.58 eV), which would allow better utilization of the solar spectrum.

• Journal for History of Mathematics
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• v.35 no.5
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• pp.131-146
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• 2022

This study is to find out how to use the materials of East Asian history in mathematics classroom. Although the use of the history of mathematics in classroom is gradually considered advantageous, the usage is mainly limited to Western mathematics history. As a result, students tend to misunderstand mathematics as a preexisting thing in Western Europe. To fix this trend, it is necessary to deal with more East Asian history of mathematics in mathematics classrooms. These activities will be more effective if they are organized in the context of students' real life or include experiential activities and discussions. Here, the study suggests a way to utilize the mathematical ideas of Bāguà and Liùshísìguà, which are easily encountered in everyday life, and some concepts presented in 『Nine Chapter』 of China and 『GuSuRyak』 of Joseon. Through this activity, it is also important for students to understand mathematics in a more everyday context, and to recognize that the modern mathematics culture has been formed by interacting and influencing each other, not by the east and the west.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.400-407
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• 2022

Innovations significantly affect the efficiency of the socioeconomic systems of the regions, acting as a system-forming element of their development. Modern models of economic development also consider innovation activity, intellectual potential, knowledge as the basic factors for stimulating the economic growth of the region. The purpose of the study is to develop methodological foundations for evaluating the effectiveness of a regional innovation system based on a multidimensional analysis of its effects. To further study the effectiveness of RIS, we have used one of the methods of multidimensional statistical analysis - canonical analysis. The next approach allows adding another important requirement to the methodological provision of evaluation of the level of innovation development of industries and regions, namely - the time factor, the formalization of which is realized in autoregressive dynamic economic and mathematical models and can be used in our research. Multidimensional Statistical Analysis for RIS effectiveness estimation was used to model RIS by typological regression. Based on it, multiple regression models were built in groups of regions with low and relatively high innovation potential. To solve the methodological problem of RIS research, we can also use the approach to the system as a "box" with inputs and outputs.

• Education of Primary School Mathematics
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• v.12 no.1
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• pp.39-55
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• 2009

For this study, the 'Game Activities' lessons presented in the math textbooks from the 1st grade to the 6th were examined in terms of learning materials, the learning members' make-up, the playing structures, and the relation with the contents. In addition, the survey by means of questionnaires was conducted to analyze the actual condition of teachers' guidance in the field. The findings from this research were as follows: First, as for the activities presented in the textbooks, it turned out that too much emphasis is placed upon plays mainly using learning materials such as cards and dice played by teams of two. In addition, there have been shown negative aspects in various ways of plays putting too much emphasis on certain types of plays such as and structures. As for the relation with the contents, although lots of efforts were taken to connect the playing activity to the lesson contents, there were units presenting plays based on the preceding lesson's repeated activity, ones that have weak link with the contents. Second, it turned out that the teachers had negative attitude on the guidance using the 'Game Activities' lesson, although they were aware of the effects of playing in math learning. This seemed to result from the delicate variety and insufficient preparation for the play. Besides, the findings indicate that the appreciation and activity of the 'Game Activities' lesson presented as a way of performance evaluation. for play need to be provided in school or classrooms for teachers and students to make good use of them.