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Search Results: 1 - 10 of 29696 matches for " Qing Qin "
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Feature Selection for Time Series Modeling  [PDF]
Qing-Guo Wang, Xian Li, Qin Qin
Journal of Intelligent Learning Systems and Applications (JILSA) , 2013, DOI: 10.4236/jilsa.2013.53017
Abstract:

In machine learning, selecting useful features and rejecting redundant features is the prerequisite for better modeling and prediction. In this paper, we first study representative feature selection methods based on correlation analysis, and demonstrate that they do not work well for time series though they can work well for static systems. Then, theoretical analysis for linear time series is carried out to show why they fail. Based on these observations, we propose a new correlation-based feature selection method. Our main idea is that the features highly correlated with progressive response while lowly correlated with other features should be selected, and for groups of selected features with similar residuals, the one with a smaller number of features should be selected. For linear and nonlinear time series, the proposed method yields high accuracy in both feature selection and feature rejection.

Quasi-Rational Canonical Forms of a Matrix over a Number Field  [PDF]
Zhudeng Wang, Qing Wang, Nan Qin
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2018, DOI: 10.4236/alamt.2018.81001
Abstract: A matrix is similar to Jordan canonical form over the complex field and the rational canonical form over a number field, respectively. In this paper, we further study the rational canonical form of a matrix over any number field. We firstly discuss the elementary divisors of a matrix over a number field. Then, we give the quasi-rational canonical forms of a matrix by combining Jordan and the rational canonical forms. Finally, we show that a matrix is similar to its quasi-rational canonical forms over a number field.
Simulations to study the static polarization limit for RHIC lattice with the Polymorphic Tracking Code
Zhe Duan,Qing Qin
Physics , 2015,
Abstract: We report a study of spin dynamics based on simulations with the Polymorphic Tracking Code (PTC), exploring the dependence of the static polarization limit on various beam parameters and lattice settings for a practical RHIC lattice.
Report on the Workshop on Accelerator R&D for Ultimate Storage Rings
Robert Hettel,Qing Qin
Physics , 2013,
Abstract: This report summaries the workshop on accelerator R&D for ultimate storage ring, held in Huairou, Beijing, Oct. 30 to Nov. 1, 2012.
Fairness or Not? Health Resources Allocation in Chongqing—Based on Theil Index  [PDF]
Yu Wang, Qing Tu, Qin Lai, Li Huang
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.37020
Abstract:

Object: To Provide a basis for the government optimizing the allocation of health resources. Methods: The overall fairness was analyzed by Theil index and Gini coefficient. The main causes of unfairness were estimated by the decomposability of Thiel index. Results: Health resources owned by the “One-hour Economic Circle” were 1.5 - 2 times than that of the “Two wings”. Theil index and Gini coefficient of five health resources from small to large were sickbed, doctor, health worker, nurse, and medical equipment. Differences within region in the contribution rate of the total Theil index were greater than the difference between region and the tendency to expand. Conclusions: The total amount of the health resources in Chongqing is insufficient. The configuration of doctor is more equitable than nurse, while the medical equipment’ fairness is worst. Differences within region mainly cause the unfairness.

Chinese Stock Price and Volatility Predictions with Multiple Technical Indicators  [PDF]
Qin Qin, Qing-Guo Wang, Shuzhi Sam Ge, Ganesh Ramakrishnan
Journal of Intelligent Learning Systems and Applications (JILSA) , 2011, DOI: 10.4236/jilsa.2011.34024
Abstract: While a large number of studies have been reported in the literature with reference to the use of Regression model and Artificial Neural Network (ANN) models in predicting stock prices in western countries, the Chinese stock market is much less studied. Note that the latter is growing rapidly, will overtake USA one in 20 - 30 years time and thus be-comes a very important place for investors worldwide. In this paper, an attempt is made at predicting the Shanghai Composite Index returns and price volatility, on a daily and weekly basis. In the paper, two different types of prediction models, namely the Regression and Neural Network models are used for the prediction task and multiple technical indicators are included in the models as inputs. The performances of the two models are compared and evaluated in terms of di- rectional accuracy. Their performances are also rigorously compared in terms of economic criteria like annualized return rate (ARR) from simulated trading. In this paper, both trading with and without short selling has been consid- ered, and the results show in most cases, trading with short selling leads to higher profits. Also, both the cases with and without commission costs are discussed to show the effects of commission costs when the trading systems are in actual use.
Linear and Nonlinear Trading Models with Gradient Boosted Random Forests and Application to Singapore Stock Market  [PDF]
Qin Qin, Qing-Guo Wang, Jin Li, Shuzhi Sam Ge
Journal of Intelligent Learning Systems and Applications (JILSA) , 2013, DOI: 10.4236/jilsa.2013.51001
Abstract:

This paper presents new trading models for the stock market and test whether they are able to consistently generate excess returns from the Singapore Exchange (SGX). Instead of conventional ways of modeling stock prices, we construct models which relate the market indicators to a trading decision directly. Furthermore, unlike a reversal trading system or a binary system of buy and sell, we allow three modes of trades, namely, buy, sell or stand by, and the stand-by case is important as it caters to the market conditions where a model does not produce a strong signal of buy or sell. Linear trading models are firstly developed with the scoring technique which weights higher on successful indicators, as well as with the Least Squares technique which tries to match the past perfect trades with its weights. The linear models are then made adaptive by using the forgetting factor to address market changes. Because stock markets could be highly nonlinear sometimes, the Random Forest is adopted as a nonlinear trading model, and improved with Gradient Boosting to form a new technique—Gradient Boosted Random Forest. All the models are trained and evaluated on nine stocks and one index, and statistical tests such as randomness, linear and nonlinear correlations are conducted on the data to check the statistical significance of the inputs and their relation with the output before a model is trained. Our empirical results show that the proposed trading methods are able to generate excess returns compared with the buy-and-hold strategy.

Response of pulmonary artery intimal sarcoma to surgery, radiotherapy and chemotherapy: a case report
Hong-qing Long, Qin Qin, Cong-hua Xie
Journal of Medical Case Reports , 2008, DOI: 10.1186/1752-1947-2-217
Abstract: Here we report a case of pulmonary artery intimal sarcoma in a 54-year-old woman presenting with complaints of shortness of breath on exertion. Echocardiography and a computed tomography scan showed that the right pulmonary artery trunk was blocked by a low-density mass. The patient was diagnosed with pulmonary artery intimal sarcoma by pathology and a complete mass resection was performed. After experiencing 10 months of disease-free survival, she was re-admitted because of the recurrence and metastasis of the tumor. Radiotherapy and chemotherapy were performed; however, only limited success was achieved. The patient died 15 months after the initial onset of symptoms.Some patients with intimal sarcoma of the pulmonary artery can benefit from radiotherapy and chemotherapy as well as surgery.Intimal sarcoma of the pulmonary artery (PA) is a very rare tumor with poor prognosis. It is frequently misdiagnosed as pulmonary thromboembolism, and in most cases the definitive diagnosis is made during surgery or upon autopsy. The defining feature of this sarcoma is local growth with slight ability to metastasize [1]. Here we present and discuss a case of PA intimal sarcoma with extensive metastases 10 months after the initial diagnosis was made during surgery.The patient, a 54-year-old woman, presented with shortness of breath on exertion over the previous three months. Physical examination revealed slight jugular vein distention (JVD); a grade III to VI systolic murmur, which was heard at the tricuspid area; and mild edema of both legs. Laboratory reports were within normal ranges. Echocardiography showed that the right PA (RPA) was almost completely obstructed by a low echogenic mass, and the left PA (LPA) was also partially obstructed, and the superior vena cava (SVC) was dilated with a diameter of about 23 mm. Right ventricle enlargement and tricuspid insufficiency were also revealed. A helical computed tomography (CT) scan showed that the RPA trunk was blocked by a soft
Analysis the Effects of Vegetables Cooperatives’ Collective Action Mechanism on Farmer’s Quality Control Behavior
Qing-song Wang,Li Qin
Advance Journal of Food Science and Technology , 2012,
Abstract: In view of the government and market mechanisms are likely to failure in the vegetable quality and safety governance, as the third sector, vegetable cooperatives involvement provides a new way to solve the problem of the quality and safety of vegetables. This study proposes five assumptions that vegetable professional cooperatives’ collective action mechanism affect of the farmers quality control behavior, select five dimensions such as trust, collaboration, commitment, adaptability and investment specificity to measure the collaborative relationship between the vegetable cooperatives and farmers. This study analysis with structural equation modeling, the results show that collective action of vegetable cooperatives has a significant positive effect on vegetables quality control standards, farmers trading environment and farmers factors endowments, vegetable trading environment has a significant positive effect on the level of vegetable quality control; factors endowments has a positive effect on farmers level of quality control, but the effect is not significant.
Buyback Contract Coordinating Supply Chain Incorporated Risk Aversion
Guangxing,Xin Deng,Yanhong Qin,Qing Wu
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: This research studies the buyback contract of a supply chain system composed of a risk-neutral supplier and a risk-averse retailer. The buyback contract is divided into two cases, the credit for all unsold goods and the credit for a partial return of goods, which are theoretically analyzed and simulated numerically respectively. The results show that when the retailer is risk averse, the supply chain system is able to achieve coordination. The buyback price is an increasing function of and the buyback ratio is also an increasing function of, while the wholesale price is a decreasing function of the risk aversion.
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