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RSVRs based on Feature Extraction: A Novel Method for Prediction of Construction Projects’ Costs
Ying Zhang,Shutian Fang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4
The construction industry is an important basis for the development of China's economy. The accurate prediction of the cost of the project determines the profitability of the project and the decision-making of the construction. Therefore, this paper combines Random Forest with Support Vector Regression, and puts forward a method of construction cost prediction based on this method which we call it Random Support Vector Regressions (RSVRs). In this paper, 22 kinds of features which are related to cost are extracted, then we use Kernel Principal Component Analysis to fuse features which are less relevant to the cost. Then 11-dimensional features are put into RSVRs for modeling. From the theoretical point of view, RSVRs gives a novel work flow that is fusing features with low correlation firstly and then performing regression. In order to avoid the defects of the regression method, the two methods are fused, so that each method can maximize its advantages and make up for the disadvantages of the other method. From a practical point of view, RSVRs can be used to predict the project cost, which not only improves the accuracy, but also immediately obtains thepredicted result. As long as the appropriate training data is selected, the method can predict the cost of any area and any building.
A Novel Method to Design Single-Sided Left-Handed Metamaterials with a Specific Frequency Band
Renjing Gao,Pengfei shi,Shutian Liu,Jian Zhao 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1
In this paper, a configuration of single-sided left-handed metamaterial (LHM) was constructed by placing one ring and metallic wire rod on the same side of a substrate. Based on this configuration, a novel approach was proposed to design LHM with a specific resonant frequency or two resonant frequencies. A LHM structure with 7.50 GHz resonant frequency was designed by optimizing the sizes of the structure, and the LHM with two resonant frequencies was subsequently constructed by placing two rings and metallic wire rod on the same side of the substrate. The left-handed properties of the proposed structures were verified by both experiments and numerical simulations.
Pengfei shi,Renjing Gao,Shutian Liu 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.5
This paper aims to establish a design tool to design the metamaterialmicrostructures with specific electromagnetic properties easily andconveniently, including the design methods of metamaterial microstructuresand the corresponding program codes. For the patch type microstructureand several typical metamaterials (such as the single-negative metamaterialswith specific negative permeability, left-handed metamaterials withspecific material constants at the prescribed frequency; single negativemetamaterials and left-handed metamaterials in prescribed frequencybands), the topology optimization models, solving schedules andcorresponding implementation program codes for microstructure designare presented in detail. Several typical metamaterial microstructures withdifferent design requirements are designed concretely. The resultsillustrated the correctness and validity of the design methods and thecorresponding program codes. The designing method proposed and theprogram codes developed in this paper provide an effective tool for thedesign of metamaterial microstructure with specific function for thedesigners.
Bai Liyi,Jiang Wei,Cheng Rui,Dang Yan,Min Li,Zhang Shutian 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.4
Background/Aims: In patients with acute nonvariceal upper gastrointestinal bleeding (ANVUGIB), the optimal timing of endoscopy is still a matter of dispute. We conducted a systematic review and meta-analysis to determine the clinical benefit of early endoscopy. Methods: A literature search of the MEDLINE, Embase, and Cochrane databases was conducted to identify publications from inception to March 1, 2022. Eligible studies included observational cohort studies and randomized controlled trials that reported clinical outcomes of endoscopy in patients with ANVUGIB. ANVUGIB patients who underwent endoscopy within 24 hours of admission were considered to have had an early endoscopy. The primary outcome was the mortality rate in ANVUGIB patients who had early or nonearly endoscopy. Results: The final analysis included five randomized controlled studies (RCTs) and 20 observational studies from the 1,206 identified articles. The mortality rate was not significantly reduced among patients who received endoscopy performed within 24 hours, whether in cohort studies nor in RCTs. For subgroup analysis, a higher mortality rate was found only among patients who received very early endoscopy within 12 hours (odds ratio, 1.66; p<0.001, I2=0) in cohort studies. No significant difference in mortality rates was found among patients at high risk of bleeding who received early versus nonearly endoscopy. Conclusions: Early endoscopy within 24 hours does not appear to significantly reduce the mortality rates of patients with ANVUGIB. Further well-designed studies are warranted to address if very early endoscopy within 12 hours can provide a clinical benefit for patients at high risk of bleeding.