• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.120-139
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• 1996

Experiment was performed to study the heat transfer characteristics in 27 kinds of 15 : 1 scale models of multi-louverred fin heat exchangers with a wide range of variables(R $e_{Lp}$ =100~1, 800, $L_p$/F$p$=0.3~0.9, $\theta$=20$^{\circ}$~40$^{\circ}$). Thermofoil heaters were used to heat the louver fins and the local average Nusselt number for each louver in the louver array was obtained at constant wall temperature conditions. Correlations are developed to predict the heat transfer characteristics and drag coefficients. Generally, the heat transfer characteristics in the multi-louvered fins is shown to be similar to those of the laminar heat transfer on a flat plate. As the Reynolds number, the louver pitch to fin pitch ratio$L_p$/F$p$and the louver angle($\theta$) increase respectively, the average Nusselt number increases, but the variation of average Nusselt number as a function of the louver angle is smaller than that as a function of the louver pitch to fin pitch ratio. In case of$L_p$/F$p$ <0.5, the average Nusselt number of the 3rd louver is especially lower than the others, it is expected that it is due to the flow structure such as a recirculation flow and a flow separation.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.689-698
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• 2019

Objectives: The study aimed to investigate the relationship between depression and number of present teeth in Korean elderly individuals. Methods: Data for this cross-sectional survey was obtained from the records of the sixth Korea National Health and Nutrition Examination Survey (KNHANES). The subjects were 1,199 Korean elderly individuals above 65 years of age. The survey and examination data were used for the independent variables. The KNHANES included health status, nutrition survey, and oral examination. $x^2-test$ was performed to identify the characteristics of depression and number of teeth present according to the characteristics of the study subjects. Logistic regression analysis was also performed to identify the relationship between depression and number of teeth present. The statistical significance level wa sset at 0.05. Results: The prevalence of depression in the subjects was 14.8%. There were statistically significant differences in the prevalence of depression, depending on gender (p<0.001), education level (p=0.001), income (p=0.001), spouse status (p<0.001), and alcohol consumption (p=0.020). The association between depression and the number of teeth present showed statistically significant difference after adjustment (p=0.040). Conclusions: Depression in elderly individuals was closely related to the number of teeth present. Therefore, public health policies for improving oral health should be established to prevent depression.

• Journal of agricultural medicine and community health
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• v.30 no.3
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• pp.263-277
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• 2005

Objectives: This study aimed to reveal the oral health conditions based on the dental health behaviors of a community-dwelling elderly. Methods: The subjects included 206 rural dwellers(100 men & 106 women) aged over 65 years old, who received dental health check-ups in the local public health center and its branches attached to 6 respective Myons of Chunchongnamdo Province, during the 2-month period from Jan. 1st to Feb. 28th, 2005. They were examined by dentists and given self-administered questionnaires asking about their dental heaith behaviors and subjective symptoms of gingival bleeding. Results: The oral health conditions based on dental health behavior showed that those who have not taken dental health service a year were found to have significantly greater number of missing teeth(p=0.002), DMFT(p=0.002) and CPITN(p=0.018), and those who have not observed intra-oral conditions a week to have significantly less number of filled teeth(p=0.002) and significantly greater number of missing teeth(p=0.000) and CPITN (p=0.000) than their respective counterparts. In terms of brushing, those who brushed their teeth below "3 times/day" were found to have significantly greater number of decayed teeth(p=0.000), missing teeth(p=0.000), DMFT(p=0.000) and CPITN(p=0.000) than their counterparts. In terms of time spent in brushing, those who spends "below 3 minutes" had significantly greater number of missing teeth(p=0.002) and DMFT(p=0.041), and significantly less number of filled teeth(p=0.036). According to the use of aid tools for cleaning teeth, the group who don't use them had significantly greater number of DMFT(p=0.041) and CPITN(p=0.018) than its counterpart. Classified by smoking habits, smoking groups had significantly greater number of decayed teeth(p=0.035) and CPITN(p=0.001) than non-smoking groups. Multiple regression analysis of the study data revealed that the significant factors influencing number of decayed teeth were number of brushing, sex and intra-oral observation (explanatory power of 14.2%). The significant factors for number of filled teeth were sex, intra-oral observation, use of aid tools, frequency of brushing, subjective health conditions and drinking of sweet beverages(explanatory power of 18.2%), those for number of missing teeth, number of brushing and age(explanatory power of 13.9%) those for DMFT, number of brushing, sex, use of dental service, age(explanatory power: 13.5%), and those for CPITN included smoking habits, use of dental service, use of aid tools (explanatory power: 10.8%). Conclusions: The study results revealed that the dental health behavior of the elderly population is in poor conditions and their consequent intra-oral health conditions are not good. To improve their oral conditions, public campaign and education will be needed to modify unhealthy dental health behaviors.

• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.323-331
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• 1995

This study was undertaken to investigate the changes of tooth contacts following orthodontic treatment , using T-Scan system. Occlusal contacts in maximum intercuspation were examined in 26 patients at the end of the active phase of orthodontic treatment and again 3 months into the retention phase to abbess the initial posttreatment occlusal changes. The obtained results of this study were as follows : 1. The mean total number of contacts increased from 11.27 at the end of orthodontic treatment to 13.15 at the fellow up visit, which was found to be statistically significant (P<0.05). 2. The change of number of contacts on anterior teeth was unchanged. 3. The change of number of contacts on posterior teeth was found to be statistically significnat (P<0.01). 4. The change of fetal number of teeth in contact was significant (P<0.05). 5. The number of ant. teeth in contact was slightly increased. but Which was not found to be statistically significant (P>0.05). 6. The number of post. teeth in contact significantly increased, which was statistically significant (P<0.05). 7. A statistically significant relationship was found between the total number of contacts at the end of treatment and the change in the contacts over time. The fewer the number of tooth contact was at the end of orthodontic treatment, the greater number of tooth contact increased over time(r=-0.38, P<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.11
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• pp.1584-1592
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• 2014

The objective was to evaluate the ingestive behavior of crossbred heifers finished on a Brachiaria brizantha cv. Marandu pasture receiving four levels of glycerin in their supplementation. Thirty-six crossbred heifers with average initial weight of $264.83{\pm}3.83kg$ and 20 months of age were distributed into a completely randomized design with four treatments and nine replications: control (0%), 4.82%, 10.12%, and 15.56% glycerin in the dry matter. The grazing time reduced linearly (p<0.05), whereas the time spent on activities like rumination, idleness, trough and total chewing time were quadratically affected (p<0.05). Bite rate and number of bites/day were quadratically influenced (p<0.05). The number of bites/swallowed cud and the number of bites/minute, however, increased linearly (p<0.05). Although the time spent on each cud and number of chews per cud were not affected (p>0.05).The number of rumination periods reduced linearly (p<0.05), whereas the number of grazing, idle and trough periods, and the times per grazing, idle, rumination and trough periods were quadratically affected (p<0.05). The feed and rumination efficiencies of the dry matter, non-fibrous carbohydrates, pasture dry matter and concentrate were quadratically affected (p>0.05) whereas the feed efficiency of neutral detergent fiber reduced linearly (p<0.05). Addition of glycerin in substitution of corn in supplements for animals managed on pastures does not influenced feed intake, but reduces the grazing time and increases the idle time. The supplementation also improves feed and rumination efficiencies.

• Journal of the Chungcheong Mathematical Society
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• v.28 no.4
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• pp.575-582
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• 2015

The Newton-Raphson method is used to compute the q-th roots of a p-adic number for a prime number q. The sufficient conditions for the convergence of this method are obtained. The speed of its convergence and the number of iterations to obtain a number of corrected digits in the approximation are calculated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.55-60
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• 2023

When performing the multiplication m×r=p of two binary numbers m and r on a computer, there is a shift-and-add(SA) method in which no time-consuming multiplication is performed, but only addition and shift-right(SR). SA is a very simple method in which when the value of the multiplier r_i is 0, the result p is only SR with m×0=0, and when r_i is 1, the result p=p+m is performed with m×1=m, and p is SR. In SA, the number of SRs can no longer be shortened, and the improvement part is whether the number of additions is shortened. This paper proposes an SA method to minimize addition based on the fact that setting a smaller number to r when converted to a binary number to be processed by a computer can significantly reduce the number of additions compared to the case of setting a smaller number to r based on the decimals that humans perform. The number of additions to the proposed algorithm was compared for four cases with signs (-,-), (-,+), (+,-), and (+,+) for some numbers in the range [-127,128]. The conclusion obtained from the experiment showed that when determining m and r, it should be determined as a binary number rather than a decimal number.

• Kyungpook Mathematical Journal
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• v.59 no.3
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• pp.515-523
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• 2019

Consider a graph G of order n and maximum degree ${\Delta}$. Let $f:V(G){\rightarrow}\{0,1,{\cdots},{\lceil}{\frac{{\Delta}}{2}}{\rceil}+1\}$ be a function that labels the vertices of G. Let $B_0=\{v{\in}V(G):f(v)=0\}$. The function f is a strong Roman dominating function for G if every $v{\in}B_0$ has a neighbor w such that $f(w){\geq}1+{\lceil}{\frac{1}{2}}{\mid}N(w){\cap}B_0{\mid}{\rceil}$. In this paper, we study the bounds on strong Roman domination numbers of the Cartesian product $P_m{\square}P_k$ of paths $P_m$ and paths $P_k$. We compute the exact values for the strong Roman domination number of the Cartesian product $P_2{\square}P_k$ and $P_3{\square}P_k$. We also show that the strong Roman domination number of the Cartesian product $P_4{\square}P_k$ is between ${\lceil}{\frac{1}{3}}(8k-{\lfloor}{\frac{k}{8}}{\rfloor}+1){\rceil}$ and ${\lceil}{\frac{8k}{3}}{\rceil}$ for $k{\geq}8$, and that both bounds are sharp bounds.

• Korean Journal of Mathematics
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• v.30 no.2
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• pp.361-362
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• 2022

It is shown that the p-part of the class number of the lower layers of a cyclotomic ℤ_p-extension can grow exponentially.

• Korean Journal of Animal Reproduction
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• v.8 no.1
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• pp.36-45
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• 1984

This study was carried out to investigate the changes in ovary in repeatedly superovulated rabbits. A total of 57 New Zealand White and Californian, 25 mature virgin and 32 immature does were used in this study. For induction of repeated superovulation, PMSG and HCG were injected at 17-day and 30-day intervals for mature does and 17-day intervals for immature ones. The repeatedly superovulated does at 17-day intervals were induced luteolysis of pseudopregnant corpus luteum with PGF2${\alpha}$ on Day 8 to 9 p.c. The effect of repeated superovulation on reproductive organs was investigated on Day 3 p.c. in mature does and on Day 3 and 6 p.c. in immature ones, respectively. 1. In mature virgin does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 7.0 and 5.0 at 17-day intervals and 13.4 and 6.0 at 30-day intervals, respectively. These numbers were statistically similar to 9.5 ovulation points in the control. However, there were less (p<0.05) ovulation points in those periods compared with 22.1 ovulation points in the 1st superovulation period. 2. In immature does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 5.3 and 2.3, respectively. These numbers were significantly (p<0.05) decreased than 17.1 ovulation points in the 1st periods. The number of ovulation points in the 2nd superovulation period was similar to that in the control, but there was a significant (p<0.05) decrease in the number of ovulation points in the 3rd period as compared to the control. 3. In mature virgin does, the number of visible normal and hemorrhagic follicles (>1.0mm diameter) on day 3 p.c. averaged 19.1 and 8.9 in the 1st superovulation period, respectively. In the 2nd 3rd superovulation period, the number of normal follicles averaged 8.3 and 15.5 at 17-day intervals and 17.8 and 14.5 at 30-day intervals. The number of hemorrhagic follicles in the 2nd and 3rd superovulation period averaged 6.3 and 2.0 at 17-day intervals and 5.2 and 7.8 at 30-day intervals, respectively. There was a slight decrease, although not significant, in the number of normal and hemorrhagic follicles in the 2nd and 3rd period at 17-day intervals compared to that in the 1st period. 4. In immature does, the number of visible normal follicles on day 3 and day 6 p.c. in the 1st superovulation period averaged 27:3 and 26.1, respectively. The follicles on day 3 p.c. tended to increase slightly more than that in the cortrol, but the average number of normal follicles on day 6 p.c. did not differ from that in the control. The number of visible hemorrhagic follicles on day 3 and day 6 p.c. in the 1st of follicles in the 1st superovulation period average 10.2 and 9.9, respectively. There was a slight increase in the number of follicles in the 1st period compared to that in the control. In the 2nd and 3rd superovulation period, the number of normal follicles revealed a slight decrease in the 3rd period, but the number of hemorrhagic follicles was not different between periods. 5. The number of growing follicles with incipient intral formation on day 3 p.c. in mature does of the 1st superovulaton period average 29.7 and the average number of growing follicles in the 3rd period was 26.7 at 17-day intervals and 31.0 at 30-day intervals, respectively. These numbers did not differ from that in the control. In immature does, the number of growing follicles averaged 57.7, 45.0 and 59.3 in the 1st, 2nd and 3rd superovulation period, respectively. There was a slight but not significant decrease in the number of growing follicles in the 3rd period compared to that in the control.