• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.354-362
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• 2016

PURPOSE. The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs). MATERIALS AND METHODS. The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (${\alpha}=.05$). RESULTS. The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups. CONCLUSION. Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized.

• The Korean Journal of Zoology
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• v.7 no.2
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• pp.41-47
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• 1964

D.auraria is a species belonging to the D.melanogaster group, and this species was divided into 3 races(A, B and C race ) by morphoogical difference of the genitals . Korean populations of D.auraria A race are polymorphic with respect to the pigmentation of the abdominal tergites. The female shows two forms of color pattern, dark and light, on the sixth to the ninth tergites, and the male has no distinction shown by the female. Crossing experiments in the laboratory have shown that the difference between these color forms is due to a single pair of allelic genes located on an autosome. In natural populations, the light forms of females are always commoner than the dark one. The number of the light form increases relatively in southern localities and decreases relatively in northern localities. Furthermore, the number of the light form increases relatively in summer and decreases relatively in fall and spring. By genetic analyses of these wild flies, the relation, d/d>d/D>D/D has been disclosed as regards the relative frequencies of the genotypes in natural populations. Three experimental populations have been set up in the laboratory. Homozygous dark forms and homozygous light forms were mixed together and cultured in population cage at the temperature of 25 $^{\circ}C$. Approximately one year later, the frequencies of the light and the dark forms reached an equilibrium , the light one being usually more frequent than the dark one. This indicates that the heterozygous dark form possesses the highest adaptive value, the homozygous light being intermediate and the homozygous dark lowest. In number of adults hached, the homozygous light form was superior to the heterozygous dark form and the homozygous dark form, but the differences are scarcely significant.

• Fashion & Textile Research Journal
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• v.13 no.6
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• pp.877-887
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• 2011

The purpose of Sassanian dynasty was to succeed the civilization of Achaemenid dynasty but it shows vestiges of Parthian civilization in many ways. This study is an attempt to take a look at Sassanian civilization through analyzing these rock reliefs since these features are shown on the rock relief of Ardashir I in early Sassanian Iran. The way carried out this study was first, to collect and search documentary data to establish the theoretical background, and collect positive data by exploring this region and then we comparatively analyzed the two data in general and the result is the following: The form of costume is different according to the person's status. In the early period of Ardashir I the costume style of the royals is reflected by clothes such as tunic, trousers in parthian style. However, trousers do not have vertical pleats which are commonly shown in the case of parthian trousers. It assumed that after the early period of Ardashir I, Sassanians formed their own styles. The form of cap is also different according to the person's status. Ardashir I and the Ahura mazda god put on crown and Korymbos which symbolized the sovereign power. Except the king and the god, the prince and the king's vassal put on high caps called Kolah. Diadem which symbolized sovereign power of king was used by the king, the god and the crown prince. There are two kinds of diadem. The first form has vertical pleats and the other does not have pleats. This form became different depending on the social position. The form of hairstyle is generally thick curly hair which goes down until the shoulder. There is no difference in their hairstyle in terms of the social position. The beard style is generally in the form of scoop. There is also no difference in terms of the person's status.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.31-40
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• 2003

In this paper, optimal cutting condition to minimize the form error in side wall machining with a flat end mill is studied. Cutting forces and tool deflection are calculated considering surface shape generated by the previous cutting such as roughing. Using the form error prediction method from tool deflection, optimal cutting condition considering form accuracy is investigated. Also, the effects of tool teeth number, tool geometry and cutting conditions on form error are analyzed. The characteristics and the difference of generated surface shape in up and down milling are discussed and over-cut free condition in up milling is presented. Form error reduction method through successive up and down milling is also suggested. The effectiveness and usefulness of the presented method are verified from a series of cutting experiments under various cutting conditions. It is confirmed that form error prediction from tool deflection in side wall machining can be used in optimal cutting condition selection and real time surface error simulation for CAD/CAM systems. This study also contributes to cutting process optimization for the improvement of form accuracy especially in precision die and mold manufacturing.

• Korean Journal of Child Studies
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• v.1
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• pp.15-27
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• 1980

PURPOSE This study was intended to analyze the play-form of normal preschool children as related to age, sex, educational experience and social maturity. METHOD 1. Subjects The subjects of this study were eighty seven 3-, 4- and 5-year-old preschool children attending educational institutions in Seoul. 2. Instruments The instruments used in this study consisted of twenty one-minute observations in 5 preschool settings and a questionnaire designed to measure the children's social maturity filled in by their parents. The observations provided information on the children's free play, that is 1) play-form: solitary, parallel and group play 2) use/non-use of toys 3) behavior: play, activity, doing nothing, onlooking 4) stationary/moving dimensions 5) play group size The questionnaire measured such factors as communication, socialization, locomotion, self-help and self-direction. 3. Data Analysis Data analysis consisted of percentage and Chi square. RESULTS 1. Play-Form The relationship between age and play-form proved to be significant at the .05 level. That is, in both boys and girls, solitary play decreased with age and group play increased with age while parallel play maintained a similar position. The relationship between sex and play-form proved to be significant at the .05 level in 3-& 4-year-old children, but not significant in 5-year-old children. That is, in their $3^{rd}$ year boys engage in the solitary play more than girls and in their $4^{th}$ year boys engage in more group play than girls. 2. Toys Without differentiation of sex and age, cases of using toys in play exceed those cases where toys were not used. 3. Behavior The relationship between age and behavior proved to be significant at the .05 level in both boys and girls. That is, with increase of age, play decreased and activity increased in boys while play increased and doing nothing decreased in girls. 4. Moving Status Totally, moving occurred more frequently in play than stationary status. Moving proved not to have a significant relationship with age, but it did Navel a significant relationship with sex at the .05 level. That is, moving tended to increase with the increase in age in both boys and girls, but not at a significant level. Boys moved significantly more than girls in all three age levels. 5. The Relationship between Educational Experience and Play-Form There was a tendency for children with longer preschool experience to engage in less solitary play and more group play than children who had less than one semester of preschool experience, but this difference was not statistically significant. 6. The Relationship between Social Maturity and Play-Form The high social maturity group engaged in less solitary play and more group play than the low social maturity group, but this was not a statistically significant difference. 7. Play Group Size Play group size was 2~10 children, but the majority of play groups consisted of 2~3 children. There was a tendency for play groups composed of 2 children to decrease with age and play groups composed of 3 children to increase with age. No significant difference was found between the sexes in play group size.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.59-65
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• 1996

A major problem in automation of turning operations is the difficulty in obtaining a sufficient and reliable chip control. Therefore it becomes desirable to find a method which can detect the chip form. Newly born chips in usual metal cutting radiate infrared rays. When such chips run out of cutting point quickly, the radiated energy from the zone around the tool is low compared with that of the case when long tangled chips are staying around the tool. The difference in chip pattern can be detected from the output of pyrometer. But, strictly speaking, only the output of pyrometer does not identify the chip form because that is the removal of chip. Therefore, in this paper, a method of the identification of chip form using output of pyrometer and fuzzy inference is developed.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.168-172
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• 1998

The morphlogical characteristics and cytotoxic acitivity for14 local varieties fo Codonopsis lanceolata collected from Korea were examined to get basic data for breeding and selection of good cultivars. Plant height ranged from 197.2 cm to 253.2 com, that from Beakunsan(No.11) was the highest and and that form Samcheok(No.5) was the lowest. Generally, plant height of those form northern area of Korea tends to be shorter than those from Southern area. Leaf width and length of that form Husando (No. 12) was the largest While that form chejudo(No.4) was the smallest and those from other areas showed no significant difference. As to the number of branches, that form Yanggu(No.1) was theleast and those from other areas did not show Chejudo(No.14) were the heaviest. Among 14 varieties tested, Heongseong(No.3) and Huksando(No.6) exhibited strong cytotoxicity , which showed 45.0 an d62.0$\mu\textrm{g}$. $m\ell$ respectively.

• Journal of Power System Engineering
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• v.4 no.4
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• pp.108-115
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• 2000

The continuous chip in turning operation deteriorates the precision of workpiece and can cause a hazardous condition to operator. Thus the chip form control becomes a very important task for reliable turning process. Using the difference of energy radiated from the chip, the chip form is identified using the neural network of supervised data. The feed mechanism is adjusted in order to break continuous chip according to the result of the chip form recognition and shows a good approach for precision turning operation.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.663-669
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• 2011

Since railway vehicle's improvements on speed and weight has caused interior noise, the passenger's convenience fell dramatically. Therefore many on-going researches are dedicated to reduce interior noise. In this study the analytical prediction of interior noise reduction has done through filling up the empty space using form and to modify the floor structure, which contributes highly with interior noises. Using Statistical Energy Analysis(SEA), the interior noise of the vehicles without the form filling on the floor structure and the vehicles with form filling and also a modified structure has been predicted. The selected percentage of form filling was 0, 50, 100% and through this research the analysis of noise reduction by form filling has been made. When floor structure has been filled with form, approximately 2 dB of noise reduction was observed and the difference of noise reduction level with 50 and 100% form filling was predicted to be very little. Through this study, the expectation of interior noise reduction in high speed trains is considered high.

• East Asian mathematical journal
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• v.16 no.1
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• pp.97-103
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• 2000

In this work, we consider a finite difference operator $L^2_N$ corresponding to $$Lu:=-(u_{xx}+u_{yy})\;in\;{\Omega},\;u=0\;on\;{\partial}{\Omega}$$, in $S_{h^2,1}$. We derive the relation between the absolute value of the bilinear form $l_{N^2}$(u, v) on $S_{h^2,1}{\times}S_{h^2,1}$ and Sobolev $H^1$ norms.