• The Journal of Fisheries Business Administration
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• v.41 no.1
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• pp.73-91
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• 2010

The objective of this study is to examine the hedging effectiveness of shrimp futures market. Hedging effectiveness is measured by OLS model based on rolling windows. Analysis data are obtained from Kansai Commodities Exchange in Osaka and are weekly data of frozen shrimp futures and cash prices in the time period from July 9, 2003, to May 9, 2007. The empirical results are summarized as follows:First, the correlation coefficients between the nearby futures price changes and the cash(16/20) price changes are very low and have range from 0.141 to 0.208 values. Second, the minimum variance hedge ratios($\hat{\beta}$) are all statistically different from 0 at the 5% level and range from 0.0477 to 0.5039 values excluding Indian shrimps(26/30). Ex post hedging effectiveness, as measured by the coefficient of determination, $R^2$, is relatively very low and range from a low of 0.4% for west-south Indian shrimps(26/30) to a high 4.3% for Vietnamese shrimps(16/20). Third, ex ante hedging effectiveness, as measured by out-of-sample hedging period, is also very low and range from a low of -4.4% for west-south Indian shrimps(21/25) to a high of 3.4% for Vietnamese shrimps(16/20). This indicates that the shrimp futures market doesn't behave as risk management instrument of shrimp spot.

• Environmental and Resource Economics Review
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• v.18 no.1
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• pp.139-158
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• 2009

With the sample of Middle East crude oil imported to South Korea, this study empirically analyzes the effectiveness of the risk management strategies using derivatives such as futures and options. Assuming the hedging period of one to twelve months, it considers a spot purchasing strategy, 1 : 1 futures hedge strategy, OLS-based minimum-variance futures hedge strategy, buying call option strategy, and collar transaction strategy. According to the ex-ante result, using the derivatives of futures or options makes lower the procurement costs when the crude oil prices is increasing. With the hedging period less than or equal to six months, the hedging strategy using futures turns out to be superior in terms of procurement cost reduction and hedging effectiveness improvement. In contrast, the hedging strategies of buying call option and collar transaction would generate better results when the hedging program last over six months.

• The Korean Journal of Financial Management
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• v.26 no.2
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• pp.155-180
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• 2009

This study is to estimate and compare hedging effectiveness in emerging currency and advanced currency futures markets. Emerging currency futures includes Korea won, Mexico peso, and Brazil real and advanced currency futures is Europe euro, British pound, and Japan yen. Hedging effectiveness is measured by comparing hedging performance of the naive hedge model, OLS model, error correction model and constant condintional correlation bivariate GARCH(1, 1) hedge model based on rolling windows. Analysis data is used daily spot and futures rates from January, 2, 2001 to March. 10, 2006. The empirical results are summarized as follows : First, irrespective of hedging period and model, hedging using Korea won/dollar futures reduces spot rate's volatility risk by 97%. Second, Korea won/dollar futures market produces the best hedging performance in emerging and advanced currency futures markets, i.e. Mexico peso, Brazil real, Europe euro, British pound, and Japan yen. Third, there are no difference of hedging effectiveness among hedging models.

• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.753-769
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• 2010

This study empirically analyzes the comparative advantages between separate hedging and complex hedging in terms of hedging effectiveness when there exist multiple risks of LNG price and exchange rate. According to the empirical ex-ante analysis, the mean of procurement costs could be reduced through hedging regardless of hedging type. In addition, the standard deviation of procurement costs could also be reduced by way of hedging, implying that a hedging should contribute to the stabilization of revenue flows. More importantly, complex hedging could be more effective for some hedging periods than separate hedging in terms of revenue stabilization. Therefore, one could verify that the hedging effects improve by making use of the variance-covariance relationship existing between commodity price and exchange rate.

• Journal of Korean Biological Nursing Science
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• v.26 no.3
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• pp.163-176
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• 2024

Purpose: This study conducted a systematic literature review and meta-analysis on the effectiveness of aromatherapy in reducing restless legs syndrome (RLS) in hemodialysis patients. Methods: Using the population, intervention, comparison, outcome, study design framework, a search was conducted of eight electronic databases: PubMed, Cochrane, Embase-Ovid, CINAHL, Web of science, Scopus, PQDT, and RISS. The population was hemodialysis patients, and the intervention included aromatherapy aiming at RLS, compared to control groups receiving placebo or usual care. The outcome measured was RLS, and the study design was randomized controlled trials. Results: The analysis included seven articles presenting results from 10 studies, and the pooled overall effect of aromatherapy on RLS in hemodialysis patients was shown by a Hedge's g of -1.84 (95% confidence interval: -2.45 to -1.23). Meta-regression analysis revealed greater effectiveness in studies that received funding. Age over 60, lavender oil use, intervention duration of less than 4 weeks, sessions longer than 30 minutes, a routine care control group, and quality assessment score of 10 or less were associated with RLS reduction. Conclusion: The study concluded that aromatherapy is effective for managing RLS in hemodialysis patients.

• Food Science of Animal Resources
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• v.42 no.2
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• pp.280-294
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• 2022

This study aimed to evaluate the effectiveness of propolis extract as a natural preservative for livestock products in term of chemical and microbiological characteristics by meta-analysis. The stages carried out in this study were identification, selection, checking suitability, and the resulting selected articles were used in the meta-analysis. The selection results obtained a total of 22 selected journal articles consisting of 9 articles for analysis of the antimicrobial activity of propolis extract and 13 articles for analysis of the chemical and mirobiological characteristics of livestock products. The articles were obtained from electronic databases, namely Science Direct and Google Scholar. The model used in this study is the random-effect model involving two groups, control and experimental. Heterogeneity and effect size values were carried out in this study using Hedge's obtained through openMEE software. Forest plot tests and data validation on publication bias was obtained using Kendall's test throught JASP 0.14.1 software. The results showed that there is a significant relationship between propolis extract with the results of the antimicrobial activity (p<0.05). In addition, the results of the application of propolis extract on the livestock products for the test microbes and the value of thiobarbituric acid reactive substances (TBARs) showed significant results (p<0.05). Conclusion based on the random-effect model on the effectiveness of antimicrobial activity of propolis extract and their apllication as a natural preservative of the chemical and microbiological characteristics of livestock products is valid by Kendall's test (p>0.05). Propolis in this case effectively used as natural preservatives in livestock products.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.169-185
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• 2020

Purpose : This study aimed to conduct a comprehensive meta-analysis to evaluate the effect size for pulmonary function and gait capacity of treadmill exercise in stroke patients. In addition, we aimed to examine the current status of treadmill interventions and compare the effect sizes of treadmill training to provide evidence-based practice for future development and application. Methods : The meta-analysis study was conducted using research articles that applied treadmill exercise to stroke patients and were published between January 2005 and February 2020. For a systematic meta-analysis, we conducted a search using the PICOS framework and selected 25 domestic stroke- and treadmill-related studies. The Comprehensive Meta-Analysis program was used to calculate the effect sizes for lung function and gait capacity (6-minute walk test and 10 m walk test). As Cohen's d has a tendency to overestimate the effect size, we used Hedge's g to increase the accuracy in computing the effect size. Results : Based on the results of the meta-analysis, the total effect size of treadmill exercise was 0.535, which was statistically significant, with a medium effect size (p<0.05). The effects of treadmill exercise in stroke patients were divided into dependent variables, namely pulmonary function (0.372) and gait capacity (0.584). In addition, for gait capacity, the effect sizes were evaluated for both the 6-minute walk test (0.756) and the 10 m walk test (0.514). Conclusion : This study provides objective evidence of the effectiveness of treadmill-based gait training programs. We hope that the results of this study will help support the development and implementation of treadmill-based gait training in stroke patients. Treadmill training is expected to improve not only pulmonary function, but also the gait capacity of stroke patients. Long-term investigations on the effects of treadmill training in stroke patients are necessary.

• Journal of Korea Trade
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• v.26 no.3
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• pp.45-62
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• 2022

Purpose - Using unexpected changes in geopolitical tensions on the Korean peninsula as a quasi-natural experimental setting, we examine whether and how geopolitical risks travel across borders through firm-level imports and exports linkages. We also test whether the effects are driven by either imports or exports and assess whether firms can effectively hedge themselves against geopolitical risks. Design/methodology - We focus on a series of unanticipated geopolitical events taken place in Korea in 2018. Making use of the shocks to geopolitical climate, we identify five milestone events toward peace talks. We employ the event studies methodology. We examine heterogenous firm-level stock price reactions around key event dates depending on firms' exposure to geopolitical risks. As a measure of firms' exposure to geopolitical risks in Korea, we utilize a text-based measure of firm-level trade links. When a firm announces and discusses its purchase of inputs from Korea or sales of outputs to Korea in their annual disclosure filings, we define a firm to have a trade relationship with Korea and have exposure to Korean geopolitical risks. Similarly, we use a measure of a firm's hedging policies based on a firm's textual mention of the use of foreign exchange derivatives in their annual disclosure. Findings - We find that U.S. firms that have direct trade links to Korea gained significantly more value when the intensity of geopolitical risks drops compared to firms without such trade links to Korea. The effects are pronounced for firms purchasing inputs from or selling outputs to Korea. We find that the effectiveness of foreign exchange hedging against geopolitical risks is limited. Originality/value - We document the international transmission of geopolitical uncertainty through trade linkages. Export links as well as import links serve as important nexus of transmission of geopolitical risks across borders. Hedging strategies involving foreign-exchanges derivatives do not seem to insulate firms again geopolitical risks. With the recent movements of localization and reshuffling of the global value chain, our results suggest a significant impact of geopolitical risks in Korea on the construction of the global value chain.