• 말소리와 음성과학
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• 제2권4호
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• pp.19-28
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• 2010

The purpose of this study was to increase the current understanding of the acoustic characteristics of voices with advancing age. The relationship between age-related changes in body physiology and certain acoustic characteristics of voice was studied in a sample of 80 men representing four chronological age groupings (20-29, 50-59, 60-69, 70-79) who were all of good physical condition. Each subject was asked to phonate the vowel /a/, /i/, and /u/ for as long as possible at comfortable frequency and intensity level and read the sentence. A promising voice analysis program (Multi-Dimensional Voice $Program^{TM}$) was used to measure the fundamental frequency ($f_0$), jitter, shimmer, $f_0$ variation, peak-amplitude variation, smoothed pitch perturbation quotient, smoothed amplitude perturbation quotient, soft phonation index, $f_0$-tremor intensity index, amplitude tremor intensity index, and noise-to-harmonics ratio from the samples.

• 한국농공학회논문집
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• 제61권1호
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• pp.31-44
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• 2019

The main objective of this research is to develop a hydroclimate drought index (HCDI) using the gridded climate data inputs in a Variable Infiltration Capacity (VIC) modeling platform. Typical drought indices, including, Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and Self-calibrated Palmer Drought Severity Index (SC-PDSI) in South Korea are also used and compared. Inverse Distance Weighting (IDW) method is applied to create the gridded climate data from 56 ground weather stations using topographic information between weather stations and the respective grid cell ($12km{\times}12km$). R statistical software packages are used to visualize HCDI in Google Earth. Skill score (SS) are computed to evaluate the drought predictability based on water information derived from the observed reservoir storage and the ground weather stations. The study indicates that the proposed HCDI with the gridded climate data input is promising in the sense that it can help us to predict potential drought extents and to mitigate its impacts in a changing climate. The longer term drought prediction (e.g., 9 and 12 month) capability, in particular, shows higher SS so that it can be used for climate-driven future droughts.

• 무역학회지
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• 제44권1호
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• pp.269-283
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• 2019

Due to environmental issues such as global warming, the importance of renewable energy is growing. Solar Power System is one of the most growing eco-friendly energy industries in the world, but Korea's solar energy industry faces fierce competition due to the trade regulations and changes in energy related laws in the major markets such as the U.S., EU and China. Therefore, Korea needs to diversify its export markets towards emerging markets. This paper analyzed 162 countries in the world and developed a model to measure how promising the countries are. GSMI(Grid connected Solar Market Index) and OSMI(Off-grid Solar Market Index) are invented based on the models. By using the developed model and the data of 162 countries over the 15-year period from 2000 to 2014, the foreign markets are ranked for searching the export market. According to the analysis, China, Japan, U.S, India and Taiwan ranked first to fifth in GSMI and OSMI ranking, which were followed by China, India, Bangladesh, Philippines and Afghanistan. The model developed through this research is expected to provide a more reasonable and scientific approach to the advancement of the Korean solar energy industry into overseas markets.

• Geomechanics and Engineering
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• 제37권4호
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• pp.371-382
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• 2024

Measurement or prediction of compression index (C_c) of soils is essential for assessment of total and differential settlement of structures. It is a well-known fact that this parameter is controlled by several index identifiers of soil including initial void ratio, Atterberg limits, overconsolidation ratio, specific gravity, etc. Many studies in the past proposed relationships for prediction of C_c based on different index properties. Therefore, this study aims to present a comparison of previously proposed equations for estimation of C_c. Data from literature was compiled, and a total of 90 and 623 test results on remolded and undisturbed specimens were used to question the validity of previously proposed equations. Nevertheless, the modeling ability of 7 and 12 equations for estimation of C_c of remolded and undisturbed soils were questioned by use of compiled data. Moreover, new empirical relationships based on initial void ratio and toughness limit for prediction of C_c was proposed by use of nonlinear multivariable regression and evolutionary based regression analyses. The results are promising-the performances of models established are quite acceptable, which are verified by statistical analyses.

• Advances in concrete construction
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• 제1권2호
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• pp.187-200
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• 2013

The damage level in structures (global scale), elements (intermediate scale) and sections (local scale) can be evaluated using a single parameter called the "Damage Index". Part of the damage attributed to the local scale relates to the damage sustained by the materials of which the section is made. This study investigates the damage of concrete subjected to monotonic compressive loading using four different damage models - one proposed here for the first time and three other well-known models. The analytical results show that the proposed model is promising yet simple and effective for evaluating the damage of concrete. The proposed damage model of concrete with its promising characteristics indicated, appears to be a useful tool in the damage assessment of structures made of concrete.

• Animal cells and systems
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• 제9권2호
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• pp.75-78
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• 2005

Fungicides and antagonists were tested for their efficacy in the management of fungal pathogens of watermelon. The fungal species in different genera were isolated from the seeds of watermelon and their vulnerability was assessed against an array of chemicals and bioagents. Among the fungal pathogens, Fusarium species were effectively controlled by Bavistin. Topsin also showed the promising effects against all the fungal pathogens, and Dithane M-45 effectively controlled Didymella bryoniae. Seed treatment with antagonists like Trichoderma harzianum and T. viride improved the seed germination, seedling vigour and reduced the incidence of seed-borne fungal pathogens. Bavistin and Topsin among chemicals increased significantly the seed germination and vigour index. Trichoderma harzianum showed its efficacy against all Fusarium species and even stood effective than Captan and Blitox. However, Pseudomonas fIuorescens also showed promising effect against Didymella bryoniae over fungicides. Under field condition, Topsin and Dithane M-45 showed better yield than Bioagents.

• 대한산업공학회지
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• 제40권2호
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• pp.240-249
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• 2014

This study aims to identify an assessment system based on multiple patent indices that can predict the likelihood of success in the commercialization of a patented technology in advance. In addition, we examine the effectiveness of our predictive model in identifying valuable technologies early on. We analyzed 3,063 secondary battery technologies patented in the US over the past 10 years. Our analysis identified 22 of the 25 most promising patented technologies, corresponding with the top 50% of industry-patented technologies that directly and indirectly succeeded in commercialization. These results support our claim that it is possible to identify attributes for the assessment of patent commercial potential to a significant degree. Our system presents a useful assessment index in the forecasting and determination of potential commercial success of patented technologies.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2003년도 춘계학술대회
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• pp.329-337
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• 2003

Stock market prediction is regarded as a challenging task of financial time-series prediction. There have been many studies using artificial neural networks in this area. Recently, support vector machines (SVMs) are regarded as promising methods for the prediction of financial time-series because they me a risk function consisting the empirical ewer and a regularized term which is derived from the structural risk minimization principle. In this study, I apply SVM to predicting the Korea Composite Stock Price Index (KOSPI). In addition, this study examines the feasibility of applying SVM in financial forecasting by comparing it with back-propagation neural networks and case-based reasoning. The experimental results show that SVM provides a promising alternative to stock market prediction.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.135-145
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• 2020

This paper provides the practical application of a linear shrinkage framework on Vietnam stock market. The cumulative data points observed in this analysis are 468 weeks from January 2011 to December 2019. All the companies listed on Ho Chi Minh City Stock Exchange (HOSE), except the companies under two years period from Initial Public Offering (IPO), are considered. The cumulative number of stocks picked is therefore 350 companies. The VNINDEX, which is the Vietnam Stock Index, is used as a reference index for shrinking to a single-index model. The empirical results show that the shrinkage of covariance matrix for portfolio optimization gives the promising results for the investors on Vietnam stock market. The shrinkage method helps the investors to produce the optimal portfolio in the sense of having higher profit with lower levels of risk compared to the portfolio of the traditional SCM method. Moreover, the portfolio turnover of shrinkage method is always kept at low magnitudes, and this makes the shrinkage portfolios save much transaction costs and reduce the liquidity risks in the trading process. In addition, the ability of shrinkage method in making profit is once again confirmed by the Alpha coefficient that achieves a high positive value.

• 산업경영시스템학회지
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• 제37권4호
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• pp.202-211
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• 2014

Pairs trading is a type of arbitrage investment strategy that buys an underpriced security and simultaneously sells an overpriced security. Since the 1980s, investors have recognized pairs trading as a promising arbitrage strategy that pursues absolute returns rather than relative profits. Thus, individual and institutional traders, as well as hedge fund traders in the financial markets, have an interest in developing a pairs trading strategy. This study proposes pairs trading rules (PTRs) created from a price ratio between securities (i.e., stock index futures) using rough set analysis. The price ratio involves calculating the closing price of one security and dividing it by the closing price of another security and generating Buy or Sell signals according to whether the ratio is increasing or decreasing. In this empirical study, we generate PTRs through rough set analysis applied to various technical indicators derived from the price ratio between KOSPI 200 and S&P 500 index futures. The proposed trading rules for pairs trading indicate high profits in the futures market.