• Journal of Educational Research in Mathematics
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• v.25 no.1
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• pp.21-58
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• 2015

The aim of this study is to look into the didactical background for teaching proportional reasoning in elementary school mathematics and offer suggestions to improve teaching proportional reasoning in the future. In order to attain these purposes, this study extracted and examined key ideas with respect to the didactical background on teaching proportional reasoning through a theoretical consideration regarding various studies on proportional reasoning. Based on such examination, this study compared and analyzed textbooks used in the United States, the United Kingdom, and South Korea. In the light of such theoretical consideration and analytical results, this study provided suggestions for improving teaching proportional reasoning in elementary schools in Korea as follows: giving much weight on proportional reasoning, emphasizing multiplicative comparison and discerning between additive comparison and multiplicative comparison, underlining the ratio concept as an equivalent relation, balancing between comparisons tasks and missing value tasks inclusive of quantitative and qualitative, algebraic and geometrical aspects, emphasizing informal strategies of students before teaching cross-product method, and utilizing informal and pre-formal models actively.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.119-140
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• 2019

Objectives: This study was based on the occurrence of a coffee roasting process-related disorder(bronchiolitis obliterans; published by NIOSH in the US) among workers exposed to chemicals called diacetyl in a coffee processing facility. Flavorings added to coffee contain diacetyl and 2,3-pentanedione, all of which are subject to exposure in a number of food manufacturing processes, including coffee roasting, grinding, and packaging. Therefore, this study aims to review the toxicity to workers related to food processing and food additive manufacturing to prevent occupational diseases. Methods: We surveyed the related literature, domestic and international references, and the status of relevant domestic and foreign professional organizations. The present situation of workers was investigated by reviewing literature on the safety and health of workers in the coffee roasting process using domestic and foreign literature and presentations. Expert advisory opinions were reflected, and experts were consulted by participating in domestic and overseas academic conferences. Results: Most of the fragrance materials for coffee were harmful and hazardous substances according to the GHS classification, and research was carried out through a second external consultation. A literature review on the measurement of air pollutant emissions from coffee roasters and the estimation of air pollutant emissions during coffee roasting examined the characteristics of pollutants emitted during coffee roasting. Conclusions: Two chemicals identified as causing bronchiolitis obliterans in the coffee roasting process are believed to explain why the disease is difficult to treat. This information can be used effectively in the future prevention of this disease. Future studies should clearly identify the potential for toxicity of alpha-diketones and the bases of OELs in relation to the occurrence of obstructive bronchiolitis, including measurement of various organic compounds and alpha-diketones from ground coffee, as well as various coffee grinds and coffee bean varieties. In particular, it is necessary to clarify the current understanding of the dose-response relationship between alpha-diketone and lung disease in workers involved in coffee roasting.

• Journal of Radiation Protection and Research
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• v.44 no.1
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• pp.8-14
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• 2019

Background: Management of an agricultural food product system following a nuclear accident is indispensable for reducing radiation exposure due to ingestion of contaminated food. The present study analyzes the effect of agricultural countermeasures on ingestion dose following a nuclear accident. Materials and Methods: Agricultural countermeasures suitable for domestic farming environments were selected by referring to the countermeasures applied after the Fukushima accident in Japan. The avertable ingestion doses that could be obtained by implementing the selected countermeasures were calculated using the Korean Agricultural Countermeasure Analysis Program (K-ACAP) to investigate the efficiency of each countermeasure. Results and Discussion: Of the selected countermeasures, the management of crops was effective when radionuclide deposition occurred during the growing season of plants. Treatment by soil additive and topsoil removal was effective when deposition occurred during the nongrowing season of plants. The disposal of milk was not effective owing to the small contribution of milk to the overall ingestion dose. Clean feeding of livestock was effective when deposition occurred during the growing season of fodder plants such as pasture and rice-straw. Finally, the effect of food restriction increased with the soil deposition density of radionuclide. The practical effect of countermeasures was very small when the avertable ingestion dose was absolutely low. Conclusion: The agricultural countermeasures selected to reduce the radionuclide ingestion dose after a nuclear accident must be made appropriate by considering the accident situation, such as the soil deposition density of the radionuclide and the deposition date in relation to farming cycles.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.81-88
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• 1997

Vanadate glasses using $B_2O_3$ as a network former and with CuO additive were mainly investigated in relation to electrical properties. Crystalline phases formed by heat-treatment in each composition were examined and dc electrical conductivity changes of the glasses were analyzed. Crystalline phases were identified as $V_3O_5,\;a-CuV_2O_6\;and\;{\beta}-CuV_2O_6$ by XRD analysis. Crystallization degrees of $V_2O_5$ and ${\beta}-CuV_2O_6$ were little changed with heat-treatment time, but those of ${\alpha}u-CuV_2O_6$ were changed sharply with heat-treatment time. The more crystallization of ${\alpha}u-CuV_2O_6$ occurred, the higher electrical conductivity was observed. Electrical conductivities with $10^{-2}~10^{-4}/{\Omega}/cm$ at room temperature(303K) could be obtained by controlling the glass compositions. The electrical conductivities were increased with increasing of $V_20_5$ content and decreasing of alkality($CuO/B_2O_3$). In this study, electron was proved to be charge carrier by seebeck coefficient measurement. Accordingly, the glasses are believed to be n-type semiconductor. Calculated activation energies for the conduction were in the range 0.098-0.124 eV. Electrical conduction mechanism was small polaron hopping without showing variable range hopping in the temperature range $30~200^{\circ}C$.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

• Korean journal of food and cookery science
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• v.11 no.5
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• pp.446-455
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• 1995

The nutritional properties of the Chol-Pyon were investigated with changing the materials (mugwort and pine leaves). In proximate composition, rice powder added mugwort and pine leaves showed the lligher con-tents of crude protein, crude lipid and crude ash than in rice powder. Ihe pH of rice powder, mugwort and pine leaves was 6.4, 6.8 and 3.5, respectively. The rice powder added pine leaves showed the lowest pH value. The content of the free sugar in raw materials for ChOl-PyOn preparation was 0.9% in rice powder, 0.3% in mugwort and 2.7％ in pine leaves. Eighteen kinds of amino acids were determined in raw materials for ChOl-fyOn preparation and their contents were 4.8% in mugwort, 4.2% in rice powder and 2.8% in pine leaves. The major minerals of raw materials for ChOl-PyOn preparation was 0.9％ increased in the order of K> Na > Mg > Ca in rice powder, Mg > K > Ca > Na in mugwort, and K > Ca > Mg > Na in pine leaves. Both of mugwort and pine leaves additives showed the higher contents of 8 kinds of minerals (Ca, Mg, K, Na, Mn, Fe, Cu, Zn) than in rice powder. In relation to changes in the texture of ChOl-PyOn, hardness, fracturability and adhesiveness at 25${\pm}$1$^{\circ}C$ were measured to be highest in white ChOl-PyOn. Cohesiveness was shown to be highest at 15％ in case of mugwort and 2.5％ in case of pine leaves. Elasticity was measured to be highest at 0.99 in case that 7.5% mugwort was added to raw materials for ChOl-PyOn. As a result of estimating the sensory qualities of the ChOl-PyOn prepared to which the additives were added in differing amounts, immediately after its preparation the mugwort additive of 7.5％ showed the superior sensory qualities Chol-PyOn (p < 0,01).

• Journal of Life Science
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• v.22 no.2
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• pp.161-166
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• 2012

This study was performed to investigate the feeding effects of different additives on the growth performance and carcass characteristics of Holstein steers. Twenty-four Holstein steers, five months of age and 176.6 kg, were randomly allocated to three experimental groups of eight animals each for an 18-month feeding trial. The groups were control (not additive), T1 (fed zinc, vitamin C, and sulfur), and T2 (fed choline and lysine). The average daily gain was no different between the treatment groups during the growing to early fattening period, but it was significantly higher in the T1 group than the T2 group in the late fattening period (p<0.05). The final BW of the T1 group was relatively high in relation to the other groups, but was not significantly different. The additives had no effects on DMI during the experimental period; however, the feed conversion ratio of the T1 group in the late fattening period was significantly lower than that of the T2 group (p<0.05). The results of yield traits, carcass weight, and yield index were similar between groups, but back fat thickness and rib eye area were relatively lower in the T2 group than in the other groups. In terms of quality traits, meat color, texture, and maturity were not significantly different between the three groups. However, marbling score and appearance rate of high quality grade ($1^{++}$, $1^+$, and 1) were higher in the T1 group compared with the T2 group. Thus, the present results suggest that vitamin C, zinc, and sulfur supplementation may improve the growth performance and carcass characteristics of Holstein steers.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.387-395
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• 2011

We analyzed the estimated daily intake of sweeteners in the Korean population, using data from national health and nutrition studies regarding the concentration of sweetener in each type of food, food intake by gender, age group, and weight. The level of safety of these sweeteners was evaluated by comparisons with the acceptable daily intake (ADI) data established by the Joint FAO/WHO expert committee on food additives. The estimated daily intake (EDI) of sodium saccharin was $52.31{\mu}g/kg{\cdot}bw$, $55.06{\mu}g/kg{\cdot}bw$ acesulpham-K, $145.47{\mu}g/kg{\cdot}bw$ aspartame, and $93.86{\mu}g/kg{\cdot}bw$ sucralose per day. The percentages in relation to ADI were 1.0%, 0.4%, 0.4%, and 0.6% respectively, which were all within safe levels. The relatively higher-consuming groups were taking $783.12{\mu}g/kg{\cdot}bw$ sodium saccharine, $4,399.09{\mu}g/kg{\cdot}bw$ aspartame, $1,557.09{\mu}g/kg{\cdot}bw$ acesulpham-k, and $2,700.72{\mu}g/kg{\cdot}bw$ sucralose per day, and their intake levels as a percentage of ADI were 15.7, 11.0, 10.4, and 18.0%, respectively, which were all within safe levels.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.225-231
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• 2002

This study was carried out to investigate the possibility of improving the texture and flavor of Dasik by adding various types of sugar (syrup, honey) and flavor ingredients (omija, chija, coffee, green tea extract) to rice powder. Dasik samples were prepared, and the sensory quality and physical characteristics of those were compared. The moisture content of Dasik added with syrup was higher than that of honey. Coffee Dasik with syrup was the highest (23.6) in moisture content. In sensory quality, the omija and coffee Dasik showed the highest score in flavor quality (p<.001). Omija Dasik with honey and coffee Dasik with syrup showed the highest scores in overall acceptability (6.4, 6.2). Green tea Dasik with syrup showed the highest value in the lightness (L) of color. Omija Dasik with syrup showed the highest value in the redness (a) of color Chija Dasik was the highest in the yellowness(b) of color. In physical characteristics, the hardness was negatively correlated with the moistness, tenderness, and texture acceptability in sensory quality(p〈0.001). The cohesiveness was positively correlated with the overall acceptability in sensory quality (p〈0.01). In the relation of texture characteristics and sensory quality, the higher the moisture content, the lower the hardness and springiness were, but the higher the brittleness and the cohesiveness were(p〈.001). Overall, omija and coffee Dasik appeared to have desirable flavor, taste and overall acceptability.

• Journal of Venture Innovation
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• v.5 no.1
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• pp.107-127
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• 2022

Global challenges such as the corona pandemic, climate change and the war-on-tech ensure that the demand who the technologies of the future develops and monitors prominently for will be on the agenda. Development of, and applications in, agrifood, biotech, high-tech, medtech, quantum, AI and photonics are the basis of the future earning capacity of the Netherlands and contribute to solving societal challenges, close to home and worldwide. To be like the Netherlands and Europe a strategic position in the to obtain knowledge and innovation chain, and with it our autonomy in relation to from China and the United States insurance, clear choices are needed. Brainport Eindhoven: Building on Philips' knowledge base, there is create an innovative ecosystem where more than 7,000 companies in the High-tech Systems & Materials (HTSM) collaborate on new technologies, future earning potential and international value chains. Nearly 20,000 private R&D employees work in 5 regional high-end campuses and for companies such as ASML, NXP, DAF, Prodrive Technologies, Lightyear and many others. Brainport Eindhoven has a internationally leading position in the field of system engineering, semicon, micro and nanoelectronics, AI, integrated photonics and additive manufacturing. What is being developed in Brainport leads to the growth of the manufacturing industry far beyond the region thanks to chain cooperation between large companies and SMEs. South-Holland: The South Holland ecosystem includes companies as KPN, Shell, DSM and Janssen Pharmaceutical, large and innovative SMEs and leading educational and knowledge institutions that have more than Invest €3.3 billion in R&D. Bearing Cores are formed by the top campuses of Leiden and Delft, good for more than 40,000 innovative jobs, the port-industrial complex (logistics & energy), the manufacturing industry cluster on maritime and aerospace and the horticultural cluster in the Westland. South Holland trains thematically key technologies such as biotech, quantum technology and AI. Twente: The green, technological top region of Twente has a long tradition of collaboration in triple helix bandage. Technological innovations from Twente offer worldwide solutions for the large social issues. Work is in progress to key technologies such as AI, photonics, robotics and nanotechnology. New technology is applied in sectors such as medtech, the manufacturing industry, agriculture and circular value chains, such as textiles and construction. Being for Twente start-ups and SMEs of great importance to the jobs of tomorrow. Connect these companies technology from Twente with knowledge regions and OEMs, at home and abroad. Wageningen in FoodValley: Wageningen Campus is a global agri-food magnet for startups and corporates by the national accelerator StartLife and student incubator StartHub. FoodvalleyNL also connects with an ambitious 2030 programme, the versatile ecosystem regional, national and international - including through the WEF European food innovation hub. The campus offers guests and the 3,000 private R&D put in an interesting programming science, innovation and social dialogue around the challenges in agro production, food processing, biobased/circular, climate and biodiversity. The Netherlands succeeded in industrializing in logistics countries, but it is striving for sustainable growth by creating an innovative ecosystem through a regional industry-academic research model. In particular, the Brainport Cluster, centered on the high-tech industry, pursues regional innovation and is opening a new horizon for existing industry-academic models. Brainport is a state-of-the-art forward base that leads the innovation ecosystem of Dutch manufacturing. The history of ports in the Netherlands is transforming from a logistics-oriented port symbolized by Rotterdam into a "port of digital knowledge" centered on Brainport. On the basis of this, it can be seen that the industry-academic cluster model linking the central government's vision to create an innovative ecosystem and the specialized industry in the region serves as the biggest stepping stone. The Netherlands' innovation policy is expected to be more faithful to its role as Europe's "digital gateway" through regional development centered on the innovation cluster ecosystem and investment in job creation and new industries.