• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.428-431
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• 2007

A floating-point number system is used to represent a wide range of real numbers using finite number of bits. The standard the IEEE adopted in 1987 divides the range of real numbers into intervals of [$2^E,2^{E+1}$), where E is an Integer represented with finite bits, and defines equally spaced equal counts of discrete numbers in each interval. Since the numbers are defined discretely, not only the number representation itself includes errors but in floating-point arithmetic some strange behaviors are observed which cannot be agreed with the real world arithmetic. In this paper errors with floating-point number representation, those with arithmetic operations, and those due to order of arithmetic operations are analyzed theoretically with help of and verification with the results of some MATLAB program executions.

• Honam Mathematical Journal
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• v.35 no.2
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• pp.137-146
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• 2013

Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to present explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function.

• Education of Primary School Mathematics
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• v.27 no.3
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• pp.247-260
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• 2024

In real life, the concepts of number range and approximation are frequently used. These concepts are closely related to various mathematical concepts, and the need for research on the defining and learning of these related terms is emphasized. The learning contents of seven mathematical terms related to the range of numbers and approximation were analyzed, focusing on the definition of terms and the context of real life. As a result of analyzing the contents of 10 currently used elementary school mathematics textbooks, the lessons were organized according to the achievement standards presented in the curriculum, but the composition and order, real-life context, examples used in definitions, and the highlighted parts and directions of the activities varied depending on the author's intent. Based on the analysis results, implications for textbook writing and classroom instruction were presented.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.78-89
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• 1996

Every mechanical component is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums. Since the range of shape variation can be represented by the variation of the coordinate system attached to the shape, the transformation matrix of the coordinate system would mathematically express the range of shape variation if the interval numbers are inserted for the elements of the transformation matrix. For the shape entity specified by the geometric tolerance with reference to datums, its range of variation can be also derived by propagating the transformation matrices composed of interval numbers. The propagation depends upon the order of precedence of datums.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.451-458
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• 1999

Purpose : To determine normal CT number range of parotid gland by analyzing the change by age increase and the difference among individuals and between both sexes in CT number of normal parotid gland. Materials & Methods : 134 subjects who took the CT scan between the period of Jan. 1996 and Dec. 1997 at Yonsei University, Dental Hospital were selected. Criteria for selection were that the patients must be within the normal range clinically and radiologically, and the entire parotid gland on the axial view must be shown. Among the axial views. the one showing the greatest parotid gland size was selected and its CT number was recorded. Also. CT numbers from both masseter muscle were recorded as its control. Results : There was statistically significant correlation between CT number of right and left of parotid glands and masseter muscles. With the increase of age. there is a significant decrease in the CT number of parotid gland(p<0.05). There was no statistically significant difference in CT number between sexes except the 7th decade and beyond age group of parotid gland(p>0.05). Conclusion : As age increases, CT number of parotid gland has a tendency to decrease, and there is no significant difference in the CT numbers between left and right parotid gland. Therefore in the CT scan of patients suspected of having a salivary gland disease of the parotid gland. to consider normal range of the age-dependent CT numbers of parotid gland and compare the CT numbers of the right and left parotid gland might be useful in diagnosing the disease.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.27-34
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• 2015

In this study, preconditioned adjoint equations for the quasi one-dimensional Euler equations are developed, and their computational benefit at all speed is assessed numerically. The preconditioned adjoint equations are derived without any assumptions on the preconditioning matrix. The dissipation for Roe type numerical flux is also suggested to scale the dissipation term properly at low Mach numbers as well as at high Mach numbers. The new preconditioned method is validated against analytical solutions. The convergence characteristics over wide range of Mach numbers is evaluated. Finally, several inverse designs for the nozzle are conducted and the applicability of the method is demonstrated.

• Journal of Mechanical Science and Technology
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• v.17 no.8
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• pp.1226-1233
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• 2003

Experimental heat transfer data for single-phase water flow in the annuli with corrugated inner tubes are presented. In the annuli with parallel flow, ten different annular arrangements are considered. For water flow rate in 1,700${\gamma}$$\^$*/). As P/e becomes closer to 8 in the range below the radius ratio (${\gamma}$$\^$*/) of 0.5, Nusselt numbers increase. However, Nusselt numbers decrease in the range above the radius ratio (${\gamma}$$\^$*/) of 0.5 because flow reattachment position becomes farther in the narrower clearance.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.4
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• pp.584-591
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• 2012

To evaluate the role of using forage, shade and shelterbelts in attracting birds into the range, three trials were undertaken with free range layers both on a research facility and on commercial farms. Each of the trials on the free range research facility in South Australia used a total of 120 laying hens (Hyline Brown). Birds were housed in an eco-shelter which had 6 internal pens of equal size with a free range area adjoining the shelter. The on-farm trials were undertaken on commercial free range layer farms in the Darling Downs in Southeast Queensland with bird numbers on farms ranging from 2,000-6,800 hens. The first research trial examined the role of shaded areas in the range; the second trial examined the role of forage and the third trial examined the influence of shelterbelts in the range. These treatments were compared to a free range area with no enrichment. Aggressive feather pecking was only observed on a few occasions in all of the trials due to the low bird numbers housed. Enriching the free range environment attracted more birds into the range. Shaded areas were used by 18% of the hens with a tendency (p = 0.07) for more hens to be in the paddock. When forage was provided in paddocks more control birds (55%) were observed in the range in morning than in the afternoon (30%) while for the forage treatments 45% of the birds were in the range both during the morning and afternoon. When shelterbelts were provided there was a significantly (p<0.05) higher % of birds in the range (43% vs. 24%) and greater numbers of birds were observed in areas further away from the poultry house. The results from the on-farm trials mirrored the research trials. Overall 3 times more hens used the shaded areas than the non shaded areas, with slightly more using the shade in the morning than in the afternoon. As the environmental temperature increased the number of birds using the outdoor shade also increased. Overall 17 times more hens used the shelterbelt areas than the control areas, with slightly more using the shelterbelts in the afternoon than in the morning. Approximately 17 times more birds used the forage areas compared to the control area in the corresponding range. There were 8 times more birds using a hay bale enriched area compared to the area with no hay bales. The use of forage sources (including hay bales) were the most successful method on-farm to attract birds into the range followed by shelterbelts and artificial shade. Free range egg farmers are encouraged to provide pasture, shaded areas and shelterbelts to attract birds into the free range.

• Speech Sciences
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• v.7 no.2
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• pp.127-137
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• 2000

This paper presents a macro script to analyze numeric sounds by a speech analysis shareware, Praat, and analyzes those sounds produced by three students who were born and raised in Pusan. Recording was done in a quiet office. To make a meaningful comparison, dynamic time points in relation to the total duration of voicing segments were determined to measure acoustical values. Results showed that a strong correlation coefficient was found between the repetitive production of numeric sounds within and across the speakers. Very high coefficients among diphthongal numbers (0 and 6) which usually show wide formant variation were noticed. This supports that each speaker produced numbers quite coherently. Also, the frequency differences between the three subjects were within a perceptually similar range. To identify a speaker among others may require to find subtle individual differences within this range. Perceptual experiments by synthesized numeric sounds may lead to resolve the issue.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.46-53
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• 2021

In the present study, wind tunnel experiments were performed to reduce the drag of a paragliding helmet in the range of Reynolds numbers from 46,000 to 155,000. The drag force of the helmet model with dimples and deflectors installed was measured by varying the dimple depth and the slant angle of the deflector. The dimples were effective in reducing the drag at low Reynolds numbers, but no significant drag reduction was found in the Reynolds number range in which an actual paraglider flight takes place. On the other hand, the deflector installed tangentially to the side outline of the helmet showed an average drag reduction of 7% in the flight Reynolds number range of real paragliding. This was because the deflector shrunk the size of the wake region and moved the wake region downstream of the deflector.