• 예술인문사회 융합 멀티미디어 논문지
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• 제8권4호
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• pp.259-267
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• 2018

부분집합 합 문제는 유한개의 정수로 이루어진 집합이 있을 때 이 집합의 부분집합 중에서 그 집합의 원소들의 합이 특정 값이 되는 경우가 있는지를 알아내는 문제로, 잘 알려진 다항식 시간 내에 풀기 어려운 NP-완비 문제이다. 유전 알고리즘은 선택과 교차, 돌연변이 등의 연산을 통해 주어진 문제의 최적해를 구하는 알고리즘이다. 동적 계획법은 주어진 문제를 풀기 위해서 문제를 하나 또는 여러 개의 하위 문제로 나누어 풀이하는 방법이다. 본 논문에서는 부분집합 합 문제를 풀이하는 유전 알고리즘을 설계 및 구현하고, 답을 찾는 데까지 걸리는 시간 성능을 동적 계획법의 경우와 실험적으로 비교하였다. 양의 정수인 원소 63 개를 가진 집합에서 '쉬움'과 '어려움'의 난이도를 고려하여 총 17 개의 문제를 선정하고, 이 문제들을 풀이하는 두 알고리즘의 성능을 비교하는 실험을 진행하였다. 17 개의 문제 중 13 개의 문제에서 본 논문에서 제시한 유전 알고리즘은 동적 계획법과 비교하여 약 84%가 우수한 시간 성능을 보였다.

• 운동영양학회지
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• 제13권1호
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• pp.75-81
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• 2009

This study aims to find out the effect of ingestion of 3 mg·kg^-1 caffeine on fluid-electrolyte balance and Tty change during exercise under heat environment of 30~32℃ (40-50% humidity). Five trained males who routinely trained for approximately 60 min·d^-1, 3-6 d·wk^-1 (age; 28.20±3.56yrs, height; 174.56±5.46 cm, body mass; 76.13±9.02 kg, body fat(%); 14.24±3.99, VO₂max; 54.00±4.30 mL·kg^-1·min^-1, exercise career; 4.20±1.95yrs) performed 40min of treadmill running in heat chamber. The study was a double-blind, randomized, crossover design. Body mass change following exercise was higher for the PLAC (Placebo) and CAFF (Caffeine) in comparison to the CON (Control), there was no significant difference between the CAFF, PLAC, CON (p= .997). The U_sg not significant differences (p= .731) and Osm_urine not significant differences between the CAFF, PLAC, CON (p= .901). There also were not significant between the CAFF, PLAC, CON for [Na⁺]_urine and [K⁺]_urine (p= .928, p= .469). In the case of Tty, although the increase rate of Tty was the highest for the CAFF on exercise early, exercise the second half in comparison to the CON and PLAC, there was not significant interaction effect between the CAFF, PLAC, and CON of Tty (p= .067), In conclusion, it was confirmed that the 3 mg·kg^-1 caffeine ingestion prior to exercising in heat environment does not impart negative effect on body fluid, electrolyte balance and changes in Tty.

• Journal of Preventive Medicine and Public Health
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• 제49권4호
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• pp.205-219
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• 2016

Objectives: No children-specified review and meta-analysis paper about the short-term effect of fine particulate matter ($PM_{2.5}$) on hospital admissions and emergency department visits for asthma has been published. We calculated more precise pooled effect estimates on this topic and evaluated the variation in effect size according to the differences in study characteristics not considered in previous studies. Methods: Two authors each independently searched PubMed and EMBASE for relevant studies in March, 2016. We conducted random effect meta-analyses and mixed-effect meta-regression analyses using retrieved summary effect estimates and 95% confidence intervals (CIs) and some characteristics of selected studies. The Egger's test and funnel plot were used to check publication bias. All analyses were done using R version 3.1.3. Results: We ultimately retrieved 26 time-series and case-crossover design studies about the short-term effect of $PM_{2.5}$ on children's hospital admissions and emergency department visits for asthma. In the primary meta-analysis, children's hospital admissions and emergency department visits for asthma were positively associated with a short-term $10{\mu}g/m^3$ increase in $PM_{2.5}$ (relative risk, 1.048; 95% CI, 1.028 to 1.067; $I^2=95.7%$). We also found different effect coefficients by region; the value in Asia was estimated to be lower than in North America or Europe. Conclusions: We strengthened the evidence on the short-term effect of $PM_{2.5}$ on children's hospital admissions and emergency department visits for asthma. Further studies from other regions outside North America and Europe regions are needed for more generalizable evidence.