• 수산해양교육연구
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• 제26권1호
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• pp.49-58
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• 2014

Variability factors of transship cargo in the container transportation market analysis short term factors. In the past, studies on the factor of variability in container cargo volume have focused on long term volume forecast and increase in investment and competitiveness from strategic perspectives. Unlike previous studies, this paper analyzes factors of variability in transshipment volume rapidly varying in short term and seeks measures. Since it was identified that transshipment volume depends on vessel operation cost and port volume in long term but effectively on special strategies launched by port authorities in short term, the port authority experienced rapid drop in volume should continue to observe strategies of competition ports and to make use of strategies seeking appropriate countermeasures.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.123-129
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• 2020

This scholarly work is an effort to capture the effects of oil prices on the actual exchange rate between dollar and rupee. This is done with reference to the U.S. dollar as oil prices are marked in USD (U.S. Dollar) in the international market, and India is among the top five importers of oil. Using monthly data from January 2001 to May 2020. The study used the real GDP, money supply, short-term interest rate difference between two countries, and inflation apart from the crude oil prices per barrel as the factors that help define the exchange rate. The analysis, through cointegration and vector error correction method (VECM), suggests long and short-run causality amid prices of oil and the rate of exchange fluctuations. Oil prices are found to be negatively related to the exchange rate in the long term but positively related in the short term. The result of the Wald test also indicates the short-run causation from the short-term interest rate and the prices of crude oil towards the exchange rate. The present study shows that oil prices are evidence of the existence of short-term and long-term driving associations with short-term interest rates and exchange rates.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.541-548
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• 2017

An increasing concern is paid to short-term voltage stability with the growth of penetration of induction motor loads. Reactive power reserve(RPR) of power system is critical to improve voltage stability. A definition of short-term voltage stability-related RPR(SVRPR) is proposed. Generators vary their contributions to voltage stability with their location and system condition, etc. Voltage support coefficient based on the second-order trace sensitivity method is proposed to evaluate SVRPR's contribution to short-term voltage stability. The evaluation method can account for the generator's reactive support in transient process and the contingency severity. Then an optimization model to improve short-term voltage stability is built. To deal with multiple contingencies, contingency weight taking into account both its probability and severity is proposed. The optimization problem is solved by primal dual interior point method. Testing on IEEE_39 bus system, it is indicated that the method proposed is effective. Short-term voltage stability is improved significantly by the way of SVRPR optimization. Hence, the approach can be used to prevent the happening of voltage collapse during system's contingency.

• 한국패류학회지
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• 제24권1호
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• pp.51-57
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• 2008

With the purpose to estimate the possibility of short-term storage and cryopreservation for sperm of Charonia sauliae, which is a potential preparation for its artificial reproduction and further research, in this study, protocols for short-term storage and cryopreservation of trumpet shell sperm was optimized. The effects of different immobilizing solutions, dilution ratios were estimated for short-term storage. And the effects of different cryoprotectant extenders and freezing rates were estimated for cryopreservation in terms of motility and survival of sperm. The results indicated that the artificial sea water of 350 mOsmol/kg is a better immobilizing solution and sperm which was diluted at a ratio of 1:1 (v/v) had higher motility and survival rate during short-term storage. The effect of 5% dimethyl sulfoxide was significantly better than those of other cryoprotectant extenders. And a freezing rate of $-20^{\circ}C\;min^{-1}$ showed better effect than other freezing rates. In conclusion, this study optimized some key factors of the short-term and cryopreservation of C. sauliae sperm, which can provide valuable data for germ-plasm conservation and artificial propagation of C. sauliae.

• 대한가정학회지
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• 제38권1호
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• pp.59-73
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• 2000

The purposes of this study were to determine the factors that influence consumer concerns for safety to cow's milk produced using food-related biotechnology and to find the similarity and difference among concern factors relating short-term and long-term risk perception. Telephone interviews were conducted and the data were collected from households(n=1,466) nationwide in the U.S. And the data were analyzed by probit model and LIMDEP softare package. The data demonstrated that consumers were concerned about food safety from consuming milk produced using food-related biotechnology. The concerns were found to be influenced by demographic factors(gender in short-term, gender and age in long-term) as well as psychological aspect such as outrage(heard about bGH, milk belief about naturalness, expected benefit in short-term, heard about bGH, expected benefit in long-term) and attitudinal factors(animal rights group, locus of control in short-term, animal rights group, cancer history, locus of control in long-term). The results suggest that consumers have concerns for safety to cow's milk produced by biotechnology and the most factors influencing consumer concerns were similar between short-term and long-term period, though a few factors such as cancer history, milk belief about naturalness and age were different.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.55-62
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• 2023

Slotted-Aloha (S-Aloha) has been widely employed in random access networks owing to its simple implementation in a distributed manner. To enhance the throughput performance of the S-Aloha, connection-based slotted-Aloha (CS-Aloha) has been proposed in recent years. The fundamental principle of the CS-Aloha is to establish a connection with a short-sized request packet before transmitting data packets. Subsequently, the connected node transmits long-sized data packets in a batch of size M. This approach efficiently reduces collisions, resulting in improved throughput compared to the S-Aloha, particularly for a large M. In this paper, we address the short-term fairness of the CS-Aloha, as quantified by Jain's fairness index. Specifically, we evaluate how equitably the CS-Aloha allocatestime slots to all nodes in the network within a finite time interval. Through simulation studies, we identify the impact of system parameters on the short-term fairness of the CS-Aloha and propose an optimal transmission probability to support short-term fairness.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3878-3887
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• 2022

For the future energy-mix policy for carbon neutrality, demand for the capability of load-follow operation has emerged in nuclear power plants in order to accommodate the intermittency of renewable energy. The short-term decay heat analysis is also required to evaluate the decay heat level varied by the power level change during the load-follow operation, which is a very important parameter in terms of short-term decay heat removal during a grace time. In this study, the short-term decay heat level for 10 days after the shutdown was evaluated for both seasonal and daily load-follow cases. Additionally, the nuclide-wise contribution to the accumulated decay heat for 10 days was analyzed for further understanding of the short-term decay heat behavior. The result showed that in the seasonal case, the decay heat level was mainly determined by the power level right before the shutdown and the amount of each nuclide was varied with the power variation due to the long variation interval of 90 days. Whereas, in the daily case, the decay heat level was strongly impacted by the average power level during operation and meaningful mass variations for those nuclides were not observed due to the short variation interval of 0.5 days.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.20-28
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• 2007

본 논문에서는 2회선 가공송전선에 대하여 2회선 중 1회선에 고장이 발생한 경우에 안전하게 운전할 수 있는 단시간정격을 결정하기 위한 해석적 방법을 기술한다. 도체의 온도특성을 나타내는 열평형방정식을 선형화 함으로써 이 선형방정식으로 1회선 선로에 과부하가 발생하는 동안 과전류와 그 온도 특성을 쉽게 표현할 수 있다. 일반적으로 단시간 선로정격은 도체의 수명과 이도를 동시에 고려하여 결정해야 한다는 것은 잘 알려진 사실이다. 그렇지만 대부분의 전력회사는 단시간정격에 대한 각자의 다른 지침을 갖고 있다. 이 논문에서는 제안된 방법을 사용하면 과거 3시기에 건설된 한국전력공사의 가공송전선에 규정된 단시간정격을 재평가할 수 있고, 그 결과 단시간정격을 효율적으로 증대시킬 수 있음을 확인하였다. 또한 이 방법은 2회선 선로 중 1회선에 고장이 발생할 경우에 기존 선로에 어떤 조치도 하지 않아도 단시간 동적송전용량을 결정하는데 직접 이용할 수 있을 것이다.

• 한국구조물진단유지관리공학회 논문집
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• 제4권4호
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• pp.171-180
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• 2000

This study aims to present a more reasonable control value than the exiting one by comparing and analyzing control values and field instrumentation values of the whole excavation depth of the four case sites using geometric averaging as a statistical method. The range of the study is confined to three things: (1) the axial force of the braced excavation walls among a variety of items prescribed in the control values by stress deformation of walls and adjacent structures; (2) by approximation of the allowable and design value; (3) and by safety factor. As a res it is desirable to revise "(Long term allowable stress + Short term allowable stress)/2 ~ Short term allowable stress," presented in the present control values by stress deformation of walls and adjacent structures, to "(Long term allowable stress + Short term allowable stress)/5 ~ (Short term allowable stress)/3." The result also shows that since there is a difference of about 3.5%, it is not necessary to revise 70, 90, and 100 percent of LEVEL I, II, and III, prescribed in the control values by the allowable and design value approximation. In addition, modifying the control value by the safety factor, now 1.07, is unnecessary, although it varies little difference from the present value.

• 천문학회보
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• 제44권1호
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• pp.52.3-52.3
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• 2019

We investigate a relative contribution from short to long-term flaring rate to predicting M and X-class flare probabilities. In this study, we consider magnetic parameters summarizing distribution and non-potentiality by Solar Dynamics Observatory/Helioseimic and Magnetic Imager and flare list by Geostationary Operational Environmental Satellites. A short-term rate is the number of major flares that occurred in an given active region (AR) within one day before the prediction time. A mid-term rate is a mean flaring rate from the AR appearance day to one day before the prediction time. A long-term rate is a rate determined from a relationship between magnetic parameter values of ARs and their flaring rates from 2010 May to 2015 April. In our model, the predicted rate is given by the combination of weighted three rates satisfying that their sum of the weights is 1. We calculate Brier skill scores (BSSs) for investigating weights of three terms giving the best prediction performance using ARs from 2015 April to 2018 April. The BSS (0.22) of the model with only long-term is higher than that with only short-term or mid-term. When short or mid-term are considered additionally, the BSSs are improved. Our model has the best performance (BSS = 0.29) when all three terms are considered, and their relative contribution from short to long-term rate are 19%, 23%, and 58%, respectively. This model seems to be more effective when predicting active solar ARs having several major flares.