• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1231-1233
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• 1996

This paper presents an estimation of relative distance and angle from a mobile robot to an object. From the number of pulses required to make the mobile robot move to the feature point, we find the relative distance and angle between the mobile robot and the object. The proposed method shows a practical way of measuring the relative distance and angle between the mobile robot and an object without setting up real world coordinate system.

• Journal of Korean Society for Quality Management
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• v.15 no.2
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• pp.74-81
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• 1987

The purpose of this paper is to find out the relative priority among the queueing products for next operation. Critical ratio scheduling is a technique for use in production scheduling to establish and maintain relative priority among the jobs. The relative priority is based on a ratio of when the completed job is required and how much time is required to complete it. A numerical example of "D" company is solved. Jobs are classified into 3 categories; the behind scheduling jobs, the on time jobs and the ahead scheduling jobs.

• Korean Journal of Mathematics
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• v.27 no.1
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• pp.17-51
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• 2019

In the paper we establish some new results depending on the comparative growth properties of composite entire and meromorphic functions using relative $_pL^*$-order, relative $_pL^*$-lower order and differential monomials, differential polynomials generated by one of the factors.

• Korean Journal of Mathematics
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• v.29 no.2
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• pp.239-252
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• 2021

The prime target of this paper is to compare some relative (k, n) Nevanlinna defects with relative (k, n) Valiron defects from the view point of integrated moduli of logarithmic derivative of entire and meromorphic functions where k and n are any two non-negative integers.

• The Pure and Applied Mathematics
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• v.30 no.2
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• pp.139-154
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• 2023

In this paper we wish to prove some results relating to the growth rates of composite entire and meromorphic functions with their corresponding left and right factors on the basis of their generalized relative order (α, β) and generalized relative lower order (α, β), where α and β are continuous non-negative functions defined on (-∞, +∞).

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.227-236
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• 1991

Background: The evaluation of individual renal function is important to diagnosis and follow-up of various diseases. Ureteral catheterization of each kidney has been widely used for this purpose, but this method had some technical difficulty, frequent complications and much restriction in reapplication. Therefore we tried to applicate radiopharmaceuticals for the evaluation of individual renal function. Methods: We measured 2 hour, 4 hour and 24 hour relative renal uptake of $^{99m}Tc-DMSA$ and relative glomerular filteration rate of $^{99m}Tc-DTPA$ with 59 patients with various renal diseases to determine their usefulness for assessment of individual renal function and to compare correlations between every renal uptake of $^{99m}Tc-DMSA$ and relative glomerular filteration rate. Results: The correlations between 2 hour-, 4 hour- and 24 hour- relative renal uptake of $^{99m}Tc-DMSA$ and relative glomerular filteration rate of $^{99m}Tc-DTPA$ were R=0.9190 (p < 0.001), R: 0.9229 (p<0.001) and R=0.9917 (p<0.001). In acute obstructive uropathy, the correlations at 2 hour and 4 houre were poor as R=0.1812 (p<0.05) and R=0.4923 (p < 0.05), but the correlation at 24 hour was good as R=0.9942 (p<0.001). Conclusions: We concluded that relative renal uptake at 2 hour and 4 hour had good correlation with relative DTPA uptake ratio in the cases without chronic renal failure and obstructive uropathy. Delayed image with 24 hour relative renal uptake $^{99m}Tc-DTPA$ had the best correlation with relative glomerular filteration rate of $^{99m}Tc-DTPA$ and that might be useful in evaluation of chronic renal disease in which showed increased beckground activity or acute obstructive uropathy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.25-34
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• 1999

The Steering and Sailing Rules of International Regulation for Preventing Collisions at Sea now in use direct actions to avoid collision when two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision. But these rules do not refer to the minimum relative distances and safety relative distances between two vessels when they should take such actions.In this paper the ship's collision avoiding actions being analyzed from a viewpoint of ship motions, the mathematical formulas to calculate such relative distances necessary for taking actions to avoid collision were worked out. The values of maneuvering indices being figured out through experiments of 20 actual ships of small, medium, large and mammoth size and applied to calculating formulas, the minimum relative distances and safety relative distances were calculated. The main results were as follows. 1. It was confirmed that the criterion elements for collision avoiding actions in head-on situation of two vessels shall be the minimum relative distances and safety relative distances between them. 2. On the assumption that two vessels same in size and condition were approaching each other in head-on situation, the minimum relative distance of small vessel(GT : 160~650tons) was found to be about 4.7 times her own length, and those of medium (GT:2,300~4,500tons),large(GT:15,000~62,000tons) and mommoth (GT:91,000~194,000tons) vessels were found to be about 5.2 times, about 5.2 times and about 6.1 times their own lengths respectively. 3. On the assumption that two vessels same in size and condition were approaching each other in head-on situation, the safe relative distance of small vessel (GT : 160~650tons) was found to be about 6.8 times her own length, and those of medium (GT : 2,300~4,500tons), large (GT: 15,000~62,000tons) and mammoth (GT : 91,000~194,000tons) vessels were found to be about 9.0 times, about 6.3 times, and about 8.0 times their own lengths respectively. 4. It is considered to be helpful for the safety of ship handling that the sufficient safe relative distances for every vessels shall be more than about 12~14 times which are 2 times minimum relative distance, their own length on above assumption.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.55-62
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• 2020

The Relative weight index is an index for evaluating nutritional condition of fish by calculating a ratio of observed weight to standard weight. The purpose of this study is estimating standard Length-Weight relationships (standard LWRs) to calculate standard weight for application of relative weight index and analyze frequency distribution of relative weight index of 10 freshwater fish in the South Korea. The standard LWRs for each species was calculated by the Length-Weight data sets from 798 times of captures at 141 sites. The correlation of determination (r²) for all species was over 0.9 and values of parameter b were within the expected range according to Froese (2006). We calculated in increments of 10 from 10 to 90 percentile of relative weight index for each species, and it could be used as a standard for quantitative assessment of nutritional condition of freshwater fish.

• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.412-424
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• 2015

Objectives: An ultra dry air environment of nearly ${\leq}2%$ RH is often required in lithium battery factories. The objective of this study is to evaluate the subjective eye, pulmonary, nose, and skin symptoms of workers exposed to ultra-low relative humidity and thionyl chloride. Methods: We recruited 274 workers using a self-reported questionnaire in March 2014. Those who worked in ultra-low relative humidity and with thionyl chloride were identified and their prevalence of symptoms was compared with that of other workers. We excluded white collar workers, researchers and other workers who were exposed to various hazard factors, and finally included 164 workers. Results: There were significant differences in the rate of self-reported eye and skin symptoms between exposure group_1 and exposure group_2. Exposure group_2 experienced more frequent eye, and skin symptoms. Multinomial logistic regression analysis for experience of dry eye symptoms and skin symptoms in exposure group_2 showed that dry eye symptoms (odds ratio [OR], 6.33, 95% confidence interval [CI], 2.19-18.24, p<0.001), and itchiness (OR, 6.45, 95% CI, 1.94-21.43, p<0.01) were the significant variables. The complaints of workers experiencing ultra-low relative humidity and thionyl chloride were high compared with other workers. Conclusion: These findings suggest that exposure to ultra-low relative humidity and thionyl chloride may be associated with more frequent eye and skin symptoms than exposure to ultra-low relative humidity alone. The current precautions to protect workers from the adverse effects of ultra-low relative humidity and thionyl chloride appear to be insufficient, indicating that additional management plans to reduce symptoms should be considered.

• Journal of Labour Economics
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• v.40 no.2
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• pp.1-29
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• 2017

We examine the extent to which students' performance relative to peers affects their career choice. Specifically, we analyze the relationship between a student's mathematics ranking in his/her school and the likelihood of choosing Mathematics and Science track in high school. Using a panel dataset of students in Seoul, we measure a student's performance using two variables: absolute performance and relative performance. The former measures a student's performance relative to the entire sample, while the latter measures performance relative to the student's peers in the same school. After controlling for test scores and other characteristics, we find that the students with a poor relative ranking are 11 percentage points less likely to choose the Mathematics and Science track. Relative performance affects girls more greatly than boys. Although relative performance affects a student's self-efficacy and class participation, our accounting exercise suggests that this channel accounts for only 12 percent of the impact, implying that students may respond to the relative ranking mostly due to other factors, such as strategic consideration to perform well in college applications.