• Journal of Educational Research in Mathematics
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• v.9 no.2
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• pp.419-438
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• 1999

This paper explored the impact of dynamic geometry software such as CabriII, GSP on student's understanding deductive justification, on the assumption that proof in school mathematics should be used in the broader, psychological sense of justification rather than in the narrow sense of deductive, formal proof. The following results have been drawn: Dynamic geometry provided positive impact on interacting between empirical justification and deductive justification, especially on understanding the necessity of deductive justification. And teacher in the computer environment played crucial role in reducing on difficulties in connecting empirical justification to deductive justification. At the beginning of the research, however, it was not the case. However, once students got intocul-de-sac in empirical justification and understood the need of deductive justification, they tried to justify deductively. Compared with current paper-and-pencil environment that many students fail to learn the basic knowledge on proof, dynamic geometry software will give more positive ffect for learning. Dynamic geometry software may promote interaction between empirical justification and edeductive justification and give a feedback to students about results of their own actions. At present, there is some very helpful computer software. However the presence of good dynamic geometry software can not be the solution in itself. Since learning on proof is a function of various factors such as curriculum organization, evaluation method, the role of teacher and student. Most of all, the meaning of proof need to be reconceptualized in the future research.

• Culinary science and hospitality research
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• v.10 no.4
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• pp.84-95
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• 2004

This study was aimed at learning how the service quality of family restaurants affects guest satisfaction and their intention to visit the restaurants once again. The method of the study was based on books and various data at home and abroad that contain service quality and guest satisfaction and guest intention to visit the place again as well. Previous studies and real guest survey were used as analyzing data. This study showed that interiors, sanitation and employee's hospitality are critical for the service quality of the restaurants, while employee's hospitality, the feature of interiors and exteriors, and sanitation management are important for guest satisfaction. It also indicated that high quality of the family restaurants, the feature of interiors and exteriors, and attractive environment as well influenced on guest intention to visit the place again. The study suggested that high quality of the family restaurants, high sanitation and resonable price all had an effect on guest satisfaction. More research should be conducted continuously to seek the ways to promote more visits to family restaurants through objective analyzing service quality.

• Journal of the East Asian Society of Dietary Life
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• v.3 no.1
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• pp.12-17
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• 1993

This book is named 'The Ryuk-Jab-Rok' because it was written in the last page of 1820's almanac. This book is written purely in Korean and has not been published yet. This book comprises twenty eight items, among which there are eight items of vegetable preserving method, ten items of Jook preparation methods(a kind of cereal soup), nine items of Pyun-Myun methods(a kind of rice cakes and noodles) and Yak-Bab(a kind of spiced rice). In vegetable preserving method, the eggplant, the cucumber and a songi mushroom were preserved with the drying method., A radish, a sorojangii, and the root of white cabbage were used with the cold temperature preservation. A garlic was dried after salting. The sprouts of DooRub, which were coming in the hot room, were used. In the Jook preparations, there were five animal materials which were lamb, chick, crudian, oyster and abalone. In nine Pyun-Myun methods, Jap-Gua-Sil was illegible because the letters were not clear. Among eight items, the stick rice was used in four cases, the regular rice in two cases. The ground pine nuts, honey and the Chinese date were used most ofter. And the sesame salt and the chestnut were next. The analysis of the terms I this book revealed that 26 items were used for cooking processes. And it also showed us that there were seven kind of cutting procedure and eight kinds of heating procedure. The shapes and size of foods were revealed at only three places in all items. The one-chi(chi ; abut three cm) and three-Ja(Ja ; about thirty cm) which the terms represent the length were revealed twice and once respectively in this book. In the taste description, 'the good', the most common word, was used in seven times, and which was the most frequently introduce case. The measuring unit is hard to revive since the measurements were taken by the container, which were Jong-Ja, Sabal and Tang-gii, then in use. Fifteen kinds of containers and cookers were used for preparing foods. And all of them are now I use.

• Herbal Formula Science
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• v.24 no.1
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• pp.17-30
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• 2016

Objectives Rehmanniae Radix Preparata was prepared in the traditional Rehmanniae Radix Preparata preparation method set forth in the 『Treasured Mirror of Eastern Medicine(Donguibogam)』 with a view to measuring the contents of 5-Hydroxymethyl-2-furaldehyde(5-HMF) at individual stages of steaming and sundrying and identifying new chemical components.Methods Based on the traditional Rehmanniae Radix Preparata preparation method set forth in the 『Treasured Mirror of Eastern Medicine』, Rehmanniae Radix Preparata steamed and sundried once through nine times was prepared. Thereafter, 5-HMF contents were analyzed and new chemical components were identified in the Rehmanniae Radix Preparata using Waters HPLC e2695, 2640 detectors, a Waters Acquity UPLC system, and a Micromass Q-TOF Premier mass spectrometer.Results The Rehmanniae Radix Preparata preparation method set forth in the 『Treasured Mirror of Eastern Medicine』 is a unique preparation method in Republic of Korea different from that in China. In the first stage of the method, fresh Rehmanniae Radix Crudus was divided into high quality, medium quality, and low quality ones named Rehmanniae Radix Crudus (Caelum)(天黃), Rehmanniae Radix Crudus (Homo)(人黃), and Rehmanniae Radix Crudus (Terra)(地黃) respectively to use Rehmanniae Radix Crudus (Caelum) and Rehmanniae Radix Crudus (Homo) for preparation of juice while using Rehmanniae Radix Crudus (Terra) to make Rehmanniae Radix Preparata. In the second stage, Rehmanniae Radix Crudus (Caelum) and Rehmanniae Radix Crudus (Terra) were made into juice and Rehmanniae Radix Crudus (Terra) was soaked in the juice. In the third stage, among auxiliary materials, rice wine named Purum Vinum Oryzae(淸酒) brewed from sticky rice was sprinkled on Rehmanniae Radix Crudus (Terra) to the extent that Rehmanniae Radix Crudus (Terra) became wet. In the fourth stage, Rehmanniae Radix Preparata steamed in earthenware steamer was dried under natural sunlight. The contents of 5-HMF in Rehmanniae Radix Preparata steamed and sundried once through nine times were shown to be below 0.1% in all cases. Pomolic acid was identified as a new chemical component.Conclusions In conclusion, the Rehmanniae Radix Preparata preparation method set forth in the 『Treasured Mirror of Eastern Medicine』 is thought to be a unique preparation method in South Korea in which Rehmanniae Radix Preparata is completed through the first stage in which fresh Rehmanniae Radix Crudus collected from fields is divided into high, medium, and low quality ones and fresh Rehmanniae Radix Crudus juice is made, the second stage in which the high quality fresh Rehmanniae Radix Crudus is soaked in the fresh Rehmanniae Radix Crudus juice, the third stage in which the fresh Rehmanniae Radix Crudus is steamed, and the fourth stage in which the steamed Rehmanniae Radix Crudus is dried.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E4
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• pp.163-168
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• 2001

Estimating the emission rate of VOCs from a gasoline industry at national level can be a challenging take even though the estimation is mean-based. However, using the procedures in the US EPA AP-42 guidelines, it is possible to approximate the mean industry emission rate once enough data are available. However, this estimate can be misled in the sense that there exist many stochastic factors in the EPA\\`s estimation procedures and also throughout the marketing channels of gasoline industry. Addressing the stochasticity problem in EPA\\`s procedure is hard to tackle because the detailed data needed to execute the estimation are not usually available even from refiners. Instead, this research tries to stay focused on the second type of stochasticity issue, raised from the mean0based metrological and marketing practice data collected from the 4 major refiners. To do so emission raters from each marketing channels (8 marketing points by 3 transportation types and by storage facilities of 4 refiners) are estimated monthly, following AP-42 procedures and using Tank 4.0. Once these estimates are acquired, the distribution of VOC emission rate for each marketing channel of all 4 refiners is estimated through simulation method using @Risk. The mean-based emission rates are weighted by company quantities to estimate the emission rate from the whole gasoline industry. Simple economic implication is provided, based on the result. This study found that, on the mean-bases, about 0.66% of gasoline marketed are evaporated into air. Considering the stochasticity in the estimation, about 90% of simulation results fell into the range of 0.65 to 0.68%. For 90% chance, the estimated economic loss is $54.65 million to $57.17 million, not counting the cost caused by air quality degradation and associated health impact.

• Journal of the Korean Society of Costume
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• v.64 no.2
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• pp.113-125
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• 2014

Creative thinking requires an ability to draw ideas on the given topic in a given time period with concentration. For this, the development process of design concept on the topic was collected through experiments and interviews targeting 10 fashion education experts and 10 clothing majors. After the analysis, the results are as follows: First of all, divergent thinking was done to find as many ideas and possibilities as possible at the step of expanding the topic by analogy. This showed characteristics of spreading thoughts through the spread of lexicon to professional field knowledge of learned, individual's cultural background, other art fields. Second, abstracted and designed words that are expanded and listed by the topic analogy were specified the topic gradually through the free combination method between lexicons. The sentences made by the combination of lexicons were interpreted through the serial listing method, in which the connection between sentences had the meaning of orderly cause and effect form, and the parallel listing method that treated information at once. Third, the few characteristics of the procedure that visualizing into the specific design are as follows. Firstly, the method to transform image that lexicon has into the one appropriate to the topic, the case that reflects external characteristics of selected designed word, and the case which reflects as the extrinsic expression of personal immanent and tactic desires. This study has its means to propose methods and directions to help create more creative and systematic ideas by analyzing the characteristics that appeared during the process of thinking language-oriented design.

• Journal of Powder Materials
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• v.25 no.6
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• pp.487-493
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• 2018

The impact of different mixing methods and sintering temperatures on the microstructure and piezoelectric properties of PZNN-PZT ceramics is investigated. To improve the sinterability and piezoelectric properties of these ceramics, the composition of $0.13Pb((Zn_{0.8}Ni_{0.2})_{1/3}Nb_{2/3})O_3-0.87Pb(Zr_{0.5}Ti_{0.5})O_3$ (PZNN-PZT) containing a Pb-based relaxor component is selected. Two methods are used to create the powder for the PZNN-PZT ceramics. The first involves blending all source powders at once, followed by calcination. The second involves the preferential creation of columbite as a precursor, by reacting NiO with $Nb_2O_5$ powder. Subsequently, PZNN-PZT powder can be prepared by mixing the columbite powder, PbO, and other components, followed by an additional calcination step. All the PZNN-PZT powder samples in this study show a nearly-pure perovskite phase. High-density PZNN-PZT ceramics can be fabricated using powders prepared by a two-step calcination process, with the addition of 0.3 wt% MnO2 at even relatively low sintering temperatures from $800^{\circ}C$ to $1000^{\circ}C$. The grain size of the ceramics at sintering temperatures above $900^{\circ}C$ is increased to approximately $3{\mu}m$. The optimized PZNN-PZT piezoelectric ceramics show a piezoelectric constant ($d_{33}$) of 360 pC/N, an electromechanical coupling factor ($k_p$) of 0.61, and a quality factor ($Q_m$) of 275.

• Journal of Periodontal and Implant Science
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• v.53 no.1
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• pp.85-95
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• 2023

Purpose: In recent years, guided implant surgery has been widely used for the convenience of patients and surgeons. Further streamlining the surgical procedure would make implant surgery more convenient. Low-speed water-free conditions are often used in guided implant surgery. Therefore, in this study, we attempted to confirm once again whether drilling was safe at a low speed without water. The main purpose of this study was to evaluate whether a simplified drilling protocol that omits some intermediate steps in the drilling process was safe from the viewpoint of heat generation. Methods: D1 density artificial bone blocks were drilled under 50 rpm, 10 N·cm water-free conditions, and the surface temperature was measured using a digital infrared camera. First, drilling was performed with the sequential drilling method, which is the most widely used technique. Second, for each drill diameter, the temperature change was measured while performing simplified drilling with omission of the previous 1, 2, or 3 steps. Results: In sequential drilling, the heat generated during drilling at all diameters was less than the critical temperature of osteonecrosis (47℃) except for the ⌀2 drill. Statistical significance was observed in all groups when comparing sequential and simplified drilling in the ⌀3.2, ⌀3.8, and ⌀4.3 drills (P<0.001). However, in the simplified drilling procedures, the temperature was below the osteonecrosis threshold temperature (47℃) except for the ⌀4.3 drill with the omission of the previous 3 steps (⌀3.0, ⌀3.2, and ⌀3.8). Conclusions: In general, drilling under low-speed, water-free conditions has shown stable results in terms of heat generation. Simplified drilling showed statistically significantly greater heat generation than sequential drilling. However, most of the diameters and omitted steps seem to be clinically acceptable, so it will be useful if an appropriate selection is made according to the patient's clinical condition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.137-142
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• 2019

There are two methods for evaluating two or more mutually exclusive projects. One is a total investment approach and the other is an incremental investment approach. The former can rank projects by the criterion of the net present value, but the latter can't do it. An incremental investment approach is only possible when all pairwise alternatives are compared. Thus an incremental investment approach is superior in ranking them over an incremental investment approach. To do so, a principle of comparison must be established. Comparisons of profitability are reasonable when operating the same amount of investment over the same period of time. One principle is that all projects are invested in the largest of the projects. Another principle is that all projects are invested during the longest project life of the projects. In this paper, even if the principle is followed, it will be shown that the external rate of return fails to rank them. However, the productive rate of return criterion would prove to be able to rank them like the net present value standard, provided that the principle of comparison is kept. In addition, rate of returns can be assessed so that all mutually exclusive projects can be compared at once, such as on the criterion of the net present value. That is, it can be also compared with many other returns, such as the profit rates on financial investments or real investments.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.53-62
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• 2013

This paper proposes a method of automatically predicting the vanishing point for the purpose of detecting the road region from natural images. The proposed method stably detects the vanishing point in the road environment by analyzing the dominant orientation of the image and predicting the vanishing point to be at the position where the feature components of the image are concentrated. For this purpose, in the first stage, the image is partitioned into sub-blocks, an edge sample is selected randomly from within the sub-block, and RANSAC is applied for line fitting in order to analyze the dominant orientation of each sub-block. Once the dominant orientation has been detected for all blocks, we proceed to the second stage and randomly select line samples and apply RANSAC to perform the fitting of the intersection point, then measure the cost of the intersection model arising from each line and we predict the vanishing point to be located at the average point, based on the intersection point model with the highest cost. Lastly, quantitative and qualitative analyses are performed to verify the performance in various situations and prove the efficiency of the proposed algorithm for detecting the vanishing point.