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Modeling strength of high-performance concrete using genetic operation trees with pruning techniques
Chien-Hua Peng,I-Cheng Yeh,Li-Chuan Lien 사단법인 한국계산역학회 2009 Computers and Concrete, An International Journal Vol.6 No.3
Regression analysis (RA) can establish an explicit formula to predict the strength of High-Performance Concrete (HPC); however, the accuracy of the formula is poor. Back-Propagation Networks (BPNs) can establish a highly accurate model to predict the strength of HPC, but cannot generate an explicit formula. Genetic Operation Trees (GOTs) can establish an explicit formula to predict the strength of HPC that achieves a level of accuracy in between the two aforementioned approaches. Although GOT can produce an explicit formula but the formula is often too complicated so that unable to explain the substantial meaning of the formula. This study developed a Backward Pruning Technique (BPT) to simplify the complexity of GOT formula by replacing each variable of the tip node of operation tree with the median of the variable in the training dataset belonging to the node, and then pruning the node with the most accurate test dataset. Such pruning reduces formula complexity while maintaining the accuracy. 404 experimental datasets were used to compare accuracy and complexity of three model building techniques, RA, BPN and GOT. Results show that the pruned GOT can generate simple and accurate formula for predicting the strength of HPC.
Hedging Performance and Stock Market Liquidity: Evidence from the Taiwan Futures Market
Hsiu-Chuan Lee,Cheng-Yi Chien 한국증권학회 2010 Asia-Pacific Journal of Financial Studies Vol.39 No.3
This paper examines the impact of stock market liquidity on the hedging performance of stock index futures, and extends the conditional OLS model described by Miffre [Journal of Futures Markets 24 (2004) 945] by including stock market liquidity in the regression model. The empirical results indicate that information regarding stock market liquidity is useful in predicting the optimal hedge ratio under different market conditions. In a bear market, the conditional OLS model with stock market liquidity provides the best hedging performance for the out-of-sample period. Although the OLS model outperforms the generalized autoregressive conditional heteroskedasticity and conditional OLS models for the out-of-sample period in a bull market, the conditional OLS model with stock market liquidity outperforms the conditional OLS model without stock market liquidity in terms of downside risks (lower partial moment).
Development of human IgE biosensor using Sezawa-mode SAW devices
Ying-Chung Chen,Wei-Tsai Chang,Chien-Chuan Cheng,Jing-Yi Shen,Kuo-Sheng Kao 한국물리학회 2014 Current Applied Physics Vol.14 No.4
This paper reports Sezawa-mode surface acoustic wave (SAW) devices with via-isolated cavity to construct the allergy biosensor. To fabricate Sezawa-mode SAW devices, the RF magnetron sputtering method for the growth of piezoelectric ZnO thin films are adopted and influences of the sputtering parameters are investigated. The optimal substrate temperature of 300 C, RF power of 120 W and sputtering pressure of 2 Pa were used to deposit piezoelectric ZnO films with a smooth surface, uniform grain size and strongly c-axis-orientated crystallization. A back-etched SAW resonator is used in this study. The wet etching of (100)-oriented silicon wafers is used to form a back-side cavity which is critical to the formation of a hopper cavity for holding bio-analytes. The remaining membrane structure silicon thickness was 25 mm. In this report, the chrome (Cr, 12 nm)/gold (Au, 66 nm) layer was initially deposited onto the sensing area of SAW devices as the binding layer for biochemical sensor. The resonance frequency of the Sezawa-mode SAW device is 1.497 GHz. The maximum sensitivity of the Sezawa-mode is calculated to be 4.44 106 cm2/g for human immunoglobulin-E (IgE) detection. The stability for human IgE detection is calculated to be 80% and the variation of the stability 3% was obtained after several tests.
Nyanti Larry Ellee,Chua Chia Zhen,Loo Han Chuan,Khor Cheng Zhi,Toh Emilia Sheau Yuin,Gill Rasvinder Singh,Chan Eng Tat,Tan Ker Yin,Rosli Taufiq,Rahim Muhammad Aklil Abd,Ibrahim Arfian,Huan Nai Chien,R 대한결핵및호흡기학회 2023 Tuberculosis and Respiratory Diseases Vol.86 No.4
Background: Attitudes towards smoking, lung cancer screening, and perceived risk of lung cancer have not been widely studied in Malaysia. The primary objective of this study was to describe the factors affecting the willingness of high-risk current smokers and ex-smokers to undergo low-dose computed tomography (LDCT) screening for lung cancer.Methods: A prospective, cross-sectional questionnaire study was conducted in current smokers or ex-smokers aged between 55 and 80 years at three hospitals in Kota Kinabalu, Sabah, Malaysia. The questionnaire recorded the following parameters: perceived lung cancer risk; Prostate Lung Colon Ovarian Cancer 2012 risk prediction model excluding race and ethnicity predictor (PLCOm2012norace); demographic characteristics; psychosocial characteristics; and attitudes towards lung cancer and lung cancer screening.Results: A vast majority of the 95 respondents (94.7%) indicated their willingness to undergo screening. Stigma of lung cancer, low levels of knowledge about lung cancer symptoms, concerns about financial constraints, and a preference for traditional medication were still prevalent among the respondents, and they may represent potential barriers to lung cancer screening uptake. A desire to have an early diagnosis (odds ratio [OR], 11.33; 95% confidence interval [CI], 1.53 to 84.05; p=0.02), perceived time constraints (OR, 3.94; 95% CI, 1.32 to 11.73; p=0.01), and proximity of LDCT screening facilities (OR, 14.33; 95% CI, 1.84 to 111.4; p=0.01) had significantly higher odds of willingness to undergo screening.Conclusion: Although high-risk current smokers and ex-smokers are likely to undergo screening for lung cancer, several psychosocial barriers persist. The results of this study may guide the policymakers and clinicians regarding the need to improve lung cancer awareness in our population.