• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.84-90
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• 2000

This study was conducted to determine the acid and phenol compounds in smoke total particulate matter(TPM) by the different tobacco variety, and grade of tobacco leaves. Sixteen kinds of tobacco leaves which were flue-curd, burley, orient, reconstituted tobacco, expanded stem, and expanded cut tobacco, were selected for this study. After collecting a TPM by using smoking machine, the concentration of TPM components was analyzed by GC. Acid components of TPM of mainstream smoke were different from the variety and grade. The order of the highest concentration of acid compounds in TPM was flue-cured > orient> burley> expanded cut tobacco> reconstituted tobacco> expanded stem. Though lactic acid and glycolic acid concentrations in flue-cured tobacco were twice higher than those in burley tobacco, the contents of 2-furoic acid and 3,4-dihydroxy butanoic acid in burley tobacco were higher than those in flue-cured tobacco. The content of phenolic compounds in the high grade and thick leaves was higher than that in other tobacco leaves. Phenol and catechol compounds in burley CD3W-2 revealed the least value in concentration among the samples tested. Pyrocatechol and hydroquinone concentrations in flue-cured tobacco were 2-3 times higher than those in burley and orient tobacco.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.163-171
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• 2011

Because Japanese cedar shows lower mechanical performance, glued-laminated timber (glulam) can be a better way to utilize Japanese cedar for structural purpose. However, low yield of higher grade lamination from log makes it difficult to design structural glulam. This study was aimed to increase the yield of higher grade lamination and provide higher efficiency of manufacturing structural lamination by ultrasonic log sorting technology. Logs were sorted by an existing log grading rule regulated by Korea Forest Research Institute (KFRI). It was found that the KFRI log grading rule contributed to finding better logs in viewpoint of the volumetric yield and it can reduce the number of rejected lumber by visual grading. However, it could not identify better logs to produce higher-grade products. To find an appropriate log-sorting-method for structural products, log diameter and ultrasonic time of flight (TOF) for the log were considered as factors to affect mechanical performance of resulting products. However, it was found that influence of log diameter on mechanical performance of resulting products was very small. The TOF showed a possibility to sort logs by mechanical performance of resulting products even though a coefficient of correlation was not strong (R = 0.6). In a case study, the log selection based on the ultrasonic TOF of the log increased the yield of the outermost tension lamination (E8 or better grade, KS F 3021) from 2.6% to 12.5% and reduced LTE5 (lower than E5 grade) lamination from 43.6% to 10.3%, compared with the existing KFRI log grading rule.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.4
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• pp.118-122
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• 2001

In this study, the variation of surface roughness was tested in surface grinding for the three working materials SM45C, heat-treated SM45C, and gray cat iron. IT was performed for the various grinding wheels with two grain size #60, #100, and three grade I, O, R and various grinding depths and feeds, The fractural grinding depths which were obtained when the grinding wheels were destructed in surface grinding works, were examined and compared with the calculated value sug-gested in this study, The results showed that the surface roughness was decreased by decreasing grinding depth, and feed, and increasing grain size and grades. The fracture grinding depths were increased by increasing grain size, grade and feed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.488-493
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• 2003

This paper presents new skill in tube-mill processing getting the increase in production efficiency and quality in response to the recent request of high grade pipe. In this study, researchers developed the method to improve the precision of pipe and tool life in tube-mill processing. Optimum tool shape is devised by analyzing various simulation and mechanism in cutting process. In order to verify the confidence of the proposed machining technology, it is applied to the real processing machinery in the field.

• Resources Recycling
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• v.28 no.3
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• pp.21-25
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• 2019

The utilization of incineration ash from municipal waste must be promoted to solve the social problem on the shortage of final disposal site. In this research, metals should be recovered to avoid the damage of the crushing machine during the utilization of incineration ash in cement industry. In fact, incineration bottom ash from municipal waste contains iron in 3-5%. Nonferrous metal and stainless steel in 1% is also included. The research and development on the physical recovery process was performed not only to remove the metals but also to recover high grade products. Metals were separated from incineration ash in Maruya Co. Ltd.. In fact, iron scrap recovered by magnetic separation can be selled. After that, mixed metal was separated from incineration ash using screen. In this research, mixed metal tried to divided copper, aluminum, brass and stainless steel using drum type magnetic separation, eddy current separation and high magnetic separation. As a result, recovered iron had an 80% for the grade. Aluminum was recovered by eddy current separation without copper and brass.

• Research in Mathematical Education
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• v.25 no.2
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• pp.135-158
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• 2022

This study aimed to building models to understand the relationships between reasoning resources and content knowledge. We applied Support Vector Machine and linear models to the data including fifth graders' scores in the Cornel Critical Thinking Test and the Iowa Assessments, demographic information, and learning science approach (a student-centered approach to learning called the Science Writing Heuristic [SWH] or traditional). The SWH model showing the relationships between critical thinking domains and academic achievement at grade 5 was developed, and its validity was tested across different learning environments. We also evaluated the stability of the model by applying the SWH models to the data of the grade levels. The findings can help mathematics educators understand how critical thinking and achievement relate to each other. Furthermore, the findings suggested that reasoning in mathematics classrooms can promote performance on standardized tests.

• Journal of Periodontal and Implant Science
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• v.53 no.1
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• pp.38-53
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• 2023

Purpose: The current Classification of Periodontal and Peri-Implant Diseases and Conditions, published and disseminated in 2018, involves some difficulties and causes diagnostic conflicts due to its criteria, especially for inexperienced clinicians. The aim of this study was to design a decision system based on machine learning algorithms by using clinical measurements and radiographic images in order to determine and facilitate the staging and grading of periodontitis. Methods: In the first part of this study, machine learning models were created using the Python programming language based on clinical data from 144 individuals who presented to the Department of Periodontology, Faculty of Dentistry, Süleyman Demirel University. In the second part, panoramic radiographic images were processed and classification was carried out with deep learning algorithms. Results: Using clinical data, the accuracy of staging with the tree algorithm reached 97.2%, while the random forest and k-nearest neighbor algorithms reached 98.6% accuracy. The best staging accuracy for processing panoramic radiographic images was provided by a hybrid network model algorithm combining the proposed ResNet50 architecture and the support vector machine algorithm. For this, the images were preprocessed, and high success was obtained, with a classification accuracy of 88.2% for staging. However, in general, it was observed that the radiographic images provided a low level of success, in terms of accuracy, for modeling the grading of periodontitis. Conclusions: The machine learning-based decision system presented herein can facilitate periodontal diagnoses despite its current limitations. Further studies are planned to optimize the algorithm and improve the results.

• Agricultural and Biosystems Engineering
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• v.3 no.1
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• pp.1-9
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• 2002

Garlic is one of the major seasoning vegetables in Korea and consumed mostly in a form of peeled cloves. Conventional Korean standards for garlic grading consist of four classes according to the size of bulb and its shape. Sorting and grading of garlic are manually done but could be in the process of automated mechanization using machine vision system in the near future. The proportion of mass of cloves in a garlic bulb to the volume of the bulb (g/ml) was determined to find out the best way of representing both the quantity and quality of cloves in each bulb. Garlic bulb was assumed as an ellipsoid and its major and minor axis and its height were measured to calculate its volume. The mass proportions and density of a garlic bulb and cloves were measured for four domestic varieties of garlic to propose it as a standard for Korean garlic grading machine.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.133-138
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• 2007

In this study, the castability and of commercially pure titanium(c.p.Ti) grade according to the casting condition which are the vacuum condition in casting machine and mold temperature of investment, was investigated. Argon-arc melt/centrifugal casting machine was used for casting the specimens. The microstructure and mechanical properties were evaluated by using optical microscope. The results were as follows; 1. It could make a sure that there's relatively not much defect of casting body of c.p.Ti according to the deference of air pressure. 2. It could make sure that it formed porosity on the surface inside of the casting body of c.p.Ti according to deferent temperature. and on excellent castability was below $200^{\circ}C$ 3. As the mold temperature of investment was increased, the lamellar structure of phase and coarse grains were shown, especially under 42MPa.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.9 no.1
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• pp.7-10
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• 2003

This study was carried out to investigate vibration shock of electric appliances during transport. Microwave oven, TV, washing machine and refrigerator were singled out as the study items. Transport courses were selected as follow ; an expressway between Kumi and Seoul for TV, an expressway between Kwangju and Seoul for microwave oven and washing machine, a national road between Inchon and Seoul for refrigerator. the values of vibration shock were measured to be ${\sim}3G$ on the national road and 1G on the expressway for up and down direction, ${\sim}0.5G$ on the national road and expressway for back and forth direction and ${\sim}0.8G$ on the national road and expressway for right and left direction. There was no damage during transport. These values were corresponding to grade II of KS A 1026 (General Rules of Performance Testing for Packaged Freights).