• Journal of Astronomy and Space Sciences
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• v.34 no.4
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• pp.257-270
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• 2017

Solar activity is known to be linked to changes in the Earth's weather and climate. Nonetheless, for other types of extreme weather, such as tropical cyclones (TCs), the available evidence is less conclusive. In this study the modulation of TC genesis over the western North Pacific by the solar activity is investigated, in comparison with a large-scale environmental parameter, i.e., El-$Ni{\tilde{n}}o$-Southern Oscillation (ENSO). For this purpose, we have obtained the best track data for TCs in the western North Pacific from 1977 to 2016, spanning from the solar cycle 21 to the solar cycle 24. We have confirmed that in the El-$Ni{\tilde{n}}o$ periods TCs tend to form in the southeast, reach its maximum strength in the southeast, and end its life as TSs in the northeast, compared with the La-$Ni{\tilde{n}}o$ periods. TCs occurring in the El-$Ni{\tilde{n}}o$ periods are found to last longer compared with the La-$Ni{\tilde{n}}o$ periods. Furthermore, TCs occurring in the El-$Ni{\tilde{n}}o$ periods have a lower central pressure at their maximum strength than those occurring in the La-$Ni{\tilde{n}}o$ periods. We have found that TCs occurring in the solar maximum periods resemble those in the El-$Ni{\tilde{n}}o$ periods in their properties. We have also found that TCs occurring in the solar descending periods somehow resemble those in the El-$Ni{\tilde{n}}o$ periods in their properties. To make sure that it is not due to the ENSO effect, we have excluded TCs both in the El-$Ni{\tilde{n}}o$ periods and in the La-$Ni{\tilde{n}}o$ periods from the data set and repeated the analysis. In addition to this test, we have also reiterated our analysis twice with TCs whose maximum sustained winds speed exceeds 17 m/s, instead of 33 m/s, as well as TCs designated as a typhoon, which ends up with the same conclusions.

• Journal of The Korean Astronomical Society
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• v.37 no.2
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• pp.79-85
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• 2004

We developed an algorithm to identify and determine periods of variable sources. With its robustness and high speed, it is expected to become an useful tool for surveys with large volume of data. This new scheme consists of an initial coarse. process of finding several candidate periods followed by a secondary process of much finer period search. With this multi-step approach, best candidates among statistically possible periods are produced without human supervision and also without any prior assumption on the nature of the variable star in question. We tested our algorithm with 381 stars taken from the ASAS survey and the result is encouraging. In about $76\%$ cases, our results are nearly identical as their published periods. Our algorithm failed to provide convincing periods for only about $10\%$ cases. For the remaining $14\%$, our results significantly differ from their periods. We show that, in many of these cases, our periods are superior and much closer to the true periods. However, the existence of failures, and also periods sometimes worse than manually controlled results, indicates that this algorithm needs further improvement. Nevertheless, the present experiment shows that this is a positive step toward a fully automated period analysis for future variability surveys.

• The Korean Journal of Ecology
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• v.8 no.1
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• pp.49-52
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• 1985

I have done several papers of flowering periods in selected floras of the world since 1969. In this paper, the patterns of flowering periods of floras, Tierra del Fuego, Isl. Barro Colorado and Karuizawa are compared. The total sums of monthly percentages of flowering taxa are 335.6 in Tierra del Fuego, 723.9 in Barro Colorado Isl. and 192.8 in Karuizawa, Japan. The patterns of Barro Colorado Isl. showed as a tropical area's patterns of flowering periods, therefore abundant flowers in there all the year round, but it is very different to tropical Java's flowering periods of the flora. The patterns of Tierra del Fuego is closely related to the patterns of flowering periods of the Falkland Isl. flora. The patterns of flowering periods of Karuiza flora is represented as patterns of northern temperate region's.

• Journal of KIISE
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• v.43 no.10
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• pp.1073-1078
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• 2016

(${\delta}$, ${\gamma}$)-matching for strings over integer alphabets can be applied to such fields as musical melody and share prices on stock markets. In this paper, we define ${\delta}$-approximate periods and ${\gamma}$-approximate periods of strings over integer alphabets. We also present two $O(n^2)$-time algorithms, each of which finds minimum ${\delta}$-approximate periods and minimum ${\gamma}$-approximate periods, respectively. Then, we provide the experimental results of execution times of both algorithms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1482-1487
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• 2011

This study evaluated the physicochemical characteristics and nutritional components of Goroshoe (Ace rmono Max.) sap related with collection periods. The changes of browning index, turbidity, pH, total acidity, organic acids, free sugar, crude protein, crude ash, and minerals were investigated. Browning index and turbidity were slightly increased, while pH and total acidity were not changed as collection periods increased. Citric acid decreased slightly from 0.081 to 0.045 mg/mL at middle collection periods. Malic acid also decreased from 0.494 to 0.416 mg/mL at middle collection periods but then afterward increased to 0.674 mg/mL as collection periods increased. Sucrose decreased from 1.759 to 1.000%, while fructose increased from 0.023 to 0.044% as collection periods increased. Crude protein increased remarkably from 0.80 to 17.49 mg% as collection periods increased. Crude ash decreased slightly from 0.04 to 0.03% at middle collection periods, and then increased afterward to 0.06% as collection periods increased. Potassium increased from 13.43 to 49.75 mg/L as collection periods increased. These results indicate that the useful components of Goroshoe sap increased with increasing collection periods, but turbidity could be reduced.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.499-503
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• 1994

One thousand and eighty eggs of Japanese quail (Coturnix coturnix Japonica) were set into the incubator maintaining 36 treatment groups (3 egg weight groups ${\times}3$ seasons ${\times}4$ preincubation holding periods) to evaluate their hatchability performances. Holding periods had significant (p<0.05) effect on hatchability and the seasons showed significant (p<0.05) effect on chick weight. All the parameters (except fertility) were significantly (p<0.01) influenced by the egg weight. None of the parameters maintained regular trend with egg weight and pre-incubation holding periods. Significant interactions were not observed on any of the parameters (except fertility) studied. The egg weight maintained significant (p<0.05) negative correlation with fertility and positive correlation with chick weight. Eggs of medium weight (9.10 to 10.00 cm) could be hatched satisfactorily between 4 and 7 days of pre-incubation holding periods in any season of the year.

• Journal of the military operations research society of Korea
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• v.30 no.2
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• pp.108-121
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• 2004

This paper deals with a procedure of changing the current inspection & replacement periods for ROKAF aircraft parts. ROKAF is mostly operating aircraft of foreign makes, and takes maintenance actions according to Technical Orders(TO.) published by foreign aircraft manufacturers. Therefore ROKAF inspects and replaces specific parts at the time noticed from T.O.. These inspection and replacement periods are determined by manufacturers according to the standard operating environment and parts' durability. But the standard operating environment Is different from operator's environment. Because of this difference, the inspection and replacement periods have to be changed according to operators' operation environment. It is resonable that the manufacturer, having design materials and life test data of parts, changes those periods together with materials of operators' operation environment. But we have many difficulties in obtaining the design materials and life test data. Then this paper proposes a procedure of changing the periods of aircraft's parts with life data obtained during operating aircraft. For the reliability analysis, a software of RELEST (Reliability Estimation Version 1.0) is used.

• The Korean Journal of Food And Nutrition
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• v.31 no.4
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• pp.449-456
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• 2018

The physicochemical characteristics and antioxidant activity of several varieties of foxtail millet were evaluated across different seeding periods. Results indicated the moisture, crude ash, fat, protein, and carbohydrate levels of the foxtail millet differed significantly according to the variety and seeding periods. The crude protein contents were highest when harvested during the early-season seeding periods; However, carbohydrate contents were highest when harvested during the late-season seeding periods. The lightness and yellowness of the Hwanggeumjo variety increased significantly as the seeding periods were delayed though the color of the Samdame variety decreased. The swelling power of foxtail millet increased as the seeding periods were delayed. Total polyphenol contents of the Hwanggeumjo and Samdame varieties were 298.68~315.13 and 288.84~297.73 mg GAE/100 g, and flavonoid contents were 181.32~172.92 and 172.49~183.86 mg CE/100 g, respectively. DPPH radical scavenging activity was 104.70~126.89 and 111.75~136.92 mg TE/100 g, and ABTS radical scavenging activity was 88.69~114.64 and 69.80~100.09 mg TE/100 g, respectively. Total polyphenol contents and the radical scavenging activity of Hwanggeumjo were highest when harvested during the seeding periods of the early-season, and Samdame was highest when harvested during the seeding periods of the late-season.

• The Korean Journal of Ecology
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• v.6 no.1
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• pp.18-21
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• 1983

Patterns of flowering periods of Ben Lawers, Eastern suburbs of Melbourne, and Tasmanian floras are compared. The total sum of each flowering period of the following floras are gradually increased from Ben Lawers to Tasmania and Eastern subarbs of Melbourne. These patterns seem to be related with the factors of temperature. A peak of the flowering periods of Ben Lawers flora occur' in July, while Eastern suburbs of Melbourne in October, and Tasmania in November to Decomber. The patterns of these flowering periods are characteristic of and divided into two categories, northern arctic and southern temperaturate hemispheric types.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.450-454
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• 2003

Natural periods are usually determined by the so-called linearized finite displacement theory even for a suspension bridge. This linearized method, with formulating structural stiffness by taking dead-load tension into consideration, calculates the natural periods of the bridge. As a result, the assumed initial tensions for each cable member may affect the accuracy of calculated natural periods and some other dynamic responses. This paper mainly demonstrates the effect of initially introduced tension accuracy on the evaluation of dynamic characteristics for a suspension bridge.