• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.363-370
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• 1995

A famous result of Chow and Robbins [8] asserts that if ${X_n, n \geq 1}$ are independent and identically distributed (i.i.d.) random variables with $E$\mid$X_1$\mid$ = \infty$, then for each sequence of constants ${M_n, n \geq 1}$ either $$ (1) lim inf_{n\to\infty} $\mid$\frac{M_n}{\sum_{j=1}^{n}X_j}$\mid$ = 0 almost certainly (a.c.) $$ or $$ (2) lim sup_{n\to\infty}$\mid$\frac{M_n}{\sum_{j=1}^{n}X_j}$\mid$ = \infty a.c. $$ and thus $P{lim_{n\to\infty} \sum_{j=1}^{n}X_j/M_n = 1} = 0$. Note that both (1) and (2) may indeed prevail.

• Journal of Power Electronics
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• v.5 no.4
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• pp.247-256
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• 2005

In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.261-261
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• 1987

황해의 조석 역학을 포함한 중규모 순환을 연구하기 위해 수립되었던 황해 조석 모델(최, 1980 ; 최, 1984)을 세격자체계로서 개선하였다. 과거 기본모델의 위도 1/5도, 경도 1/4도의 해상도(약 12 해리)는 본 모델에 의해 위도 1/15도, 경도 1/12도의 세격자체계로서 육붕 전역을 자세히 해상시켰다. 모델은 일차적으로 주태음반일주조에 의한 황해의 평균 조석 상황을 재현시키는데 이용되었으며 산정된 조류의 검증은 86년 동계의 해양관측중 해류관측결과(미국 Florida 주립대 - 성균관대 협력연구)로서 수행하였다. 계산 결과에 의하면 과거 모델보다 높은 해상력에 의해 연안에서의 조석 파급 효과가 개선되게 산정되었으므로 연안 해양학적인 각종 응용에 더 나은 입력 및 해석에 이용될 수 있다. 계산 시간간격은 69.00333초로서 1태음조석 주기당 648 timestep 을 형성하였는데 매 조석주기당 약 80 C.P.U.(분)이었으며 7번째 조석주기의 산정 결과를 분석하는데 이용하였다. 본 연구는 기보고된 세계 여타 해역의 육붕모델보다도 자세한 해상도를 갖는 3차원 모델의 결과로서 여겨진다. 아마도 육붕단의 조석 관측이 모델 개선을 위해 필수적인 사항으로 대두되는데 이는 조석 입력(예: 구주 서측 deamphidromic zone)의 중요성이 판별되었기 때문이다. 모델을 이용한 추후의 연구는 극한 상황의 3차원적 해류 분포, 대륙붕 해저 경계층 연구를 포함하는 퇴적 역학 연구 등이 될 것이다.

• Journal of the Korean Mathematical Society
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• v.44 no.4
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• pp.787-797
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• 2007

In this paper, the following fourth-order rational difference equation $$x_{n+1}=\frac{{x_n^b}+x_n-2x_{n-3}^b+a}{{x_n^bx_{n-2}+x_{n-3}^b+a}$$, n=0, 1, 2,..., where a, b ${\in}$ [0, ${\infty}$) and the initial values $X_{-3},\;X_{-2},\;X_{-1},\;X_0\;{\in}\;(0,\;{\infty})$, is considered and the rule of its trajectory structure is described clearly out. Mainly, the lengths of positive and negative semicycles of its nontrivial solutions are found to occur periodically with prime period 15. The rule is $1^+,\;1^-,\;1^+,\;4^-,\;3^+,\;1^-,\;2^+,\;2^-$ in a period, by which the positive equilibrium point of the equation is verified to be globally asymptotically stable.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1561-1567
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• 2000

An experiment was conducted to investigate the effect of dietary protein levels and supplementation of phytase and pentosanase in wheat-soybean meal diet on the performance and output of N and P in broilers. Addition of phytase alone or in combination with pentosanase to reduced or control protein diets did not affect average final body weight of mixed sexes. However, addition of phytase and pentosanase in combination to reduced protein diets in male broilers significantly depressed body weights. Intestinal viscosity of 21d broilers was significantly decreased by addition of phytase and pentosanase alone or in combination. Tibia ash content was significantly increased by phytase supplementation. Supplementation of phytase alone and in combination with pentosanase to reduced protein diets significantly decreased P in manure and daily output of P. Daily N output was lowest in the reduced protein diet supplemented with phytase and pentosanase combination. The retention of DM, N and P was highest in the reduced protein diet supplemented with phytase and pentosanase combination. In conclusion, supplementation of phytase alone or in combination with pentosanase to reduced protein diets can decrease output of N and P. But the combination of the enzymes has no beneficial effects on the performance of broilers, especially those on wheat-soybean meal diet with reduced protein level.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.68.1-68.1
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• 2012

We present a comprehensive study of the stellar populations in two faint M31 dwarf satellites, And XI and And XIII. Using deep archival images from the Wide Field Planetary Camera 2 (WFPC2) onboard the Hubble Space Telepscope (HST), we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new template light curve fitting routine (RRFIT) detected RRL populations from both galaxies. The mean periods of $RR_{ab}$ (RR0) stars in And XI and And XIII are < $P_{ab}$ > = $0.621{\pm}0.040$, and < $P_{ab}$ > = $0.648{\pm}0.038$ respectively. Even though the RRL populations show a lack of $RR_{ab}$ stars with high amplitudes (Amp(V) > 1.0 mag) and relatively short periods ($P_{ab}$ ~ 0.5 days), their period - V band amplitude (P-Amp(V)) relations track the lower part of the general P-Amp(V) trend in the M31 outer halo RRL populations. The metallicities of $RR_{ab}$ stars were calculated via the [Fe/H]-log $P_{ab}$-Amp(V) relationship of Alcock et al. The metallicities thus obtained ($[Fe/H]_{And}$ $_{XI}=-1.75%$; $[Fe/H]_{And}$ $_{XIII}=-1.74$) are consistent with the values calculated from the RGB slope indicating that our measurements are not significantly affected by the evolutionary effects of RRL stars. We discuss the origins of And XI and And XIII based on a comparative analysis of the luminosity-metallicity (L-M) relation of Local Group dwarf galaxies.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.19-23
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• 2011

In this study three types of domatia; Tuft (T), Pocket-Tuft (PT) and Pocket (P) were observed on some species of the genus Cornus. Cornus officinalis Sieb & Zuee and C. florida Linnaeus possess T type, C. controversa Hemsl and C. walteri Wangerin possess PT type while C. alba Linnaeus possess P type. A total of 120 leaves were investigated for foliar mite's population. T type domatia was the habitat of 329 mites (48.89%), followed by PT type where 198 mites (29.41%) were found, and the least favored was the P type domatia that accommodated 146 mites (21.70%) out of 673 mites in total. The mean number of mites per domatia was $8({\pm}0.22)$, $4({\pm}0.95)$ and $3({\pm}0.70)$ for T, PT and P type, respectively. The alternative hypothesis that foliar mites prefer T type domatia as a habitat than PT and P type domatia was accepted based on these findings at a probability of P<0.05. Thus, it was concluded that foliar mites prefer T type domatia than the other two types. This could be due to the nature and efficiency of T type domatia in ensuring mites protection from predators and unfriendly environmental conditions. Therefore, the presence of denser tufts lowers the risks of predation and unfriendly environmental conditions and results in a higher number of mites.

• Nutrition Research and Practice
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• v.13 no.3
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• pp.240-246
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• 2019

BACKGROUND/OBJECTIVES: Diabetes is diagnosed after an average of 10-12 years of diabetic development. Strict glycemic control in diabetic patients promotes the normalization of blood glucose and reduces cardiovascular diseases (CVDs) and diabetic complications. Therefore, early diagnosis in non-aware individuals is very important. SUBJECTS/METHODS: Clinical indices and nutrient intakes in Korean diabetic adults aged 19-64 years were examined according to the awareness of diabetes, using 2012 and 2013 Korea National Health and Nutrition Examination Survey (KNHANES) data. The aware group was defined as individuals who were aware of having diabetes from diagnosis by physician before the survey and the non-aware group as individuals who were not aware of having diabetes. RESULTS: The average age was higher in the aware group compared to the non-aware group in both men (P = 0.002) and women (P = 0.004). The prevalences of hypertension and dyslipidemia were not different between the two groups, but the diagnosis rate was significantly lower in the non-aware group. In the non-aware group, total and LDL-cholesterol were significantly higher (P < 0.001), the risk for total cholesterol over 240 mg/dL was 3.4 times (95% CI: 1.58-7.52) higher (P = 0.002) and the risk for LDL-cholesterol over 160 mg/dL was 4.59 times (95% CI: 2.07-10.17) higher (P < 0.001). The calorie intake of the female non-aware group was significantly higher compared to the female aware group (P = 0.033). CONCLUSION: The results suggested that the recommendation of screening test is necessary even for young adults. Studies on the methodology for early diagnosis of diabetes are also needed.

• Mycobiology
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• v.29 no.2
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• pp.85-89
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• 2001

URP primers of 20 mer derived from repetitive sequence of rice were used to assess genetic variation of oyster mushroom consisting of 10 cultivars of Pleurotus ostreatus, two cultivars of P. florida and two cultivars of P. sajor-caju which were registered in Korea. URP2F and URP38F primers produced cultivar-specific PCR polymorphic bands in the Pleurotus species. UPGMA cluster analysis using the URP-PCR data showed that 14 Pleurotus cultivars are genetically clustered into large three groups. The URP-PCR data provided important information for more efficient breeding strategies of Pleurotus cultivars.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E3
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• pp.129-136
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• 2003

Effects of inorganic aerosols on the kinetics of the hydroxyl radical reactions with selected aliphatic alkanes have been investigated using the relative rate technique. The relative rates in the absence and presence of aerosols were determined for n-butane, n-pentane, n-hexane, n-octane, and n-decane. P-xylene was used as a reference compound. Inorganic aerosols including (NH$_4$)$_2$SO$_4$, NH$_4$NO$_3$, and NaCl aerosols at two different aerosol concentrations that are typical of polluted urban conditions were tested. Total surface areas of aerosols were 1400 (Condition I) and 3400 $\mu$$m^2$ cm$^{-3}$ (Condition II). Significant changes in the relative rates in the presence of the inorganic aerosols were not observed for the n-butanel/$.$OH, n-pentanel/$.$OH, n-hexanel/$.$OH, n-octanel/$.$OH, and n-decanel/$.$OH reactions versus p-xylenel/$.$OH reaction. These results suggest that the promoting effects depend on the semiconducting property of the aerosols and the nature of the organic compounds.