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Fuzzy set theory has attracted many researchers’ interests and many efficient variants have been implemented in support system, decision-making and other fields. Inspired by the idea of variable weight analysis, in this study, we investigate state variable weight vector and its properties, propose two kinds of variable weight aggregation operators such as variable weight averaging (VWA) operator and variable weight geometric (VWG) operator based on three types of fuzzy attribute values. Finally, we apply in ship evaluation and economy collaboration evaluation tasks and make comparison analysis to illustrate the effectiveness of our proposed technique.

The carboxylation of unsaturated hydrocarbons using CO2 offers a highly appealing access to valuable carboxylic acids, while selectively obtaining the anti-Markovnikov product still remains a chall...

With the rapid development of DC transmission technology, DC circuit breakers, the key equipment for DC fault handling, have become a research hotspot of scholars. This paper proposes a novel hybrid DC circuit breaker topology to improve the shortcomings of traditional hybrid DC circuit breakers. Traditional hybrid DC circuit breakers use too many IGBTs, which results in a large volume and a high cost. The main innovation of this topology is the use of a mechanical switch in series in a solid-state branch, which withstands most of the voltage. An oscillating circuit is in parallel on the mechanical switch, which can generate reverse current to reduce the current flowing through the mechanical switch to zero, to achieve arc free breaking. The feasibility of the proposed topology is verified based on a PSCAD simulation platform. It should serve as a valuable reference for the design of DC distribution systems and DC breakers.

We present the results of a four-month, spectroscopic campaign of the Wolf-Rayet dust-making binary, WR137. We detect only small-amplitude, random variability in the CIII5696 emission line and its integrated quantities (radial velocity, equivalent width, skewness, kurtosis) that can be explained by stochastic clumps in the wind of the WC star. We find no evidence of large-scale, periodic variations often associated with Corotating Interaction Regions that could have explained the observed intrinsic continuum polarization of this star. Our moderately high-resolution and high signal-to-noise average Keck spectrum shows narrow double-peak emission profiles in the Halpha, Hbeta, Hgamma, HeII6678 and HeII5876 lines. These peaks have a stable blue-to-red intensity ratio with a mean of 0.997 and a root-mean-square of 0.004, commensurate with the noise level; no variability is found during the entire observing period. We suggest that these profiles arise in a decretion disk around the O9 companion, which is thus an O9e star. The characteristics of the profiles are compatible with those of other Be/Oe stars. The presence of this disk can explain the constant component of the continuum polarization of this system, for which the angle is perpendicular to the plane of the orbit, implying that the rotation axis of the O9e star is aligned with that of the orbit. It remains to be explained why the disk is so stable within the strong ultraviolet radiation field of the O star. We present a binary evolutionary scenario that is compatible with the current stellar and system parameters., 12 pages, 5 Figures

High overpotential is one of the disadvantages of lithium–air batteries, which can cause electrolyte decomposition to damage the electrochemical performance of the battery. Redox mediators (RMs) have been extensively investigated for reducing the overpotential of Li–O2 batteries. However, most RMs have a limited effect on overpotential reduction and can only reach about 3.5 V. Herein, we report the use of a p-phenylenediamine oligomer (pPO) as an effective dual-functional RM to significantly reduce the charge potential to 3.1 V and to enhance the discharge capacity and rate capability. During the discharge process, pPO containing a benzoquinone group, is first reduced to pPOo−, which adsorbs lithium ions and oxygen, and promotes the formation of lithium peroxide. During charging, pPO containing active N sites is preferentially oxidized to pPON+, which combines with lithium peroxide and promotes its decomposition. Similarly, we synthesized two other oligomers (mPO and oPO) that do not affect the overpotential due to differences in the molecular structure. Furthermore, pPO can also promote surface passivation of the lithium anode by forming a protective layer that allows facile cycling of the cells directly in air. The special molecular structure and functional groups determine the interaction between the RM and products. This study offers insights into designing bifunctional RMs to improve both the oxygen reduction and the oxygen evolution reaction activities in Li–O2 batteries.

Deception detection has been studied for hundreds of years. A particularly challenging problem is to not only identify truth from deception, but also discriminate misinformation, i.e. errors, from ...

The interval-valued hesitant fuzzy set, which allows decision makers to use several interval numbers to assess a variable, is a useful tool to deal with situations in which people are hesitant in providing their interval-valued assessments. In this paper, we introduce the concept of weighted interval-valued hesitant fuzzy set, in which different weights are designed to these possible membership degrees, and the weights indicate that the decision maker has different confidence in giving every possible assessment of the membership degree. Then we define some basic operations such as union, intersection, complement, multiplication and power operation of weighted interval-valued hesitant fuzzy sets and weighted interval-valued hesitant fuzzy elements, discuss their operation properties, and propose the score function of the weighted interval-valued hesitant fuzzy element to compare two weighted hesitant fuzzy elements. Furthermore, we introduce the concept of hesitance degree of weighted interval-valued hesitant fuzzy element, present four aggregation operators such as the weighted interval-valued hesitant fuzzy-weighted averaging operator, the weighted interval-valued hesitant fuzzy-weighted geometric operator, the generalized weighted interval-valued hesitant fuzzy-weighted averaging operator and the generalized weighted interval-valued hesitant fuzzy-weighted geometric operator to aggregate weighted interval-valued hesitant fuzzy information, and build the mathematical model of multi-criteria group decision making based on the expert weights (known and unknown). Finally, a numerical example is given to illustrate the effectiveness and feasibility of our proposed method.

High-frequency trading (HFT) has been challenging fintech and data science. HFT trading marker prediction is a rarely investigated but important problem in finance and data science. In this study, we first propose locally linear embedding based HFT marker prediction algorithm to tackle this problem and HFT trading marker evaluation algorithms for validation. Our results demonstrate locally linear embedding (LLE) outperform its peers in capturing trading markers in terms of accuracy and complexity for its local data structure keeping mechanism in embedding.

Hesitant interval-valued fuzzy set, which allows decision makers to use several interval numbers to assess a variable, is a useful tool to deal with situations in which people are hesitant in providing their interval-valued assessments. In this paper, we investigate the properties of hesitant interval-valued fuzzy aggregation operators and the approach for ranking a set of hesitant interval-valued fuzzy elements. Some flaws about the properties presented by Wei et al. (Knowl Based Syst 46:43–53, 2013) are pointed out and analyzed by counterexamples, and some modifications on the properties are given. Simultaneously, two flaws about the approach for ranking hesitant interval-valued fuzzy elements provided by Wei et al. (2013) are analyzed by counterexamples. A new algorithm for ranking a set of hesitant interval-valued fuzzy elements is provided. The rationality of the modified ranking approach is investigated.

While there have been a dozen of authoring systems and programming toolkits for visual design and development, users who do not have programming skills, such as data analysts or interface designers, still may feel cumbersome to efficiently implement a web-based visualization.In this paper, we present ECharts, an open-sourced, web-based, cross-platform framework that supports the rapid construction of interactive visualization. The motivation is driven by three goals: easy-to-use, rich built-in interactions, and high performance. The kernel of ECharts is a suite of declarative visual design language that customizes built-in chart types. The underlying streaming architecture, together with a high-performance graphics renderer based on HTML5 canvas, enables the high expandability and performance of ECharts. We report the design, implementation, and applications of ECharts with a diverse variety of examples. We compare the utility and performance of ECharts with C3.js, HighCharts, and Chart.js. Results of the experiments demonstrate the efficiency and scalability of our framework. Since the first release in June 2013, ECharts has iterated 63 versions, and attracted over 22,000 star counts and over 1700 related projects in the GitHub. ECharts is regarded as a leading visualization development tool in the world, and ranks the third in the GitHub visualization tab. MSC: 00-01, 99-00, Keywords: Information visualization, Web-based visualization

The main feature of Pythagorean fuzzy sets is that it is characterized by four parameters, namely membership degree, nonmembership degree, strength of commitment about membership, and direction of commitment. In this paper, we propose a variety of distance measures for Pythagorean fuzzy sets and Pythagorean fuzzy numbers, which take into account the four parameters of Pythagorean fuzzy sets. Finally, a numerical example is provided to illustrate the validity and applicability of the presented distance measures.

In this paper, we first analyze several existing ranking approaches for a set of interval numbers which are based on the possibility degree matrix. We show by counterexamples that these methods are not appropriate to rank a set of interval numbers from two viewpoints. Furthermore, we investigate the relationship between the possibility degree matrix and the reciprocal fuzzy preference matrix and analyze the reason that leads to the irrational ranking result. Finally, we propose an improved ranking algorithm for a set of interval numbers based on the Boolean matrix. Two numerical examples and a practical application are provided to illustrate the feasibility and effectiveness of our proposed method.

In this study, an improved method of capillary electrophoresis for simultaneous detection of acephate and isocarbophos was developed. The ionic liquids (ILs) of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) and sodium dodecyl sulfate (SDS) were added as modifiers in the background electrolyte (BGE) for capillary electrophoresis to enhance the separation efficiency of acephate and isocarbophos. The separation conditions in terms of the concentrations of the IL, SDS, and pH were optimized. The limits of detection of the method for acephate and isocarbophos were 0.15 and 0.08 mg/kg. The relative standard deviation (RSD) for five replicates of acephate and isocarbophos solution (5.0 mg/L) was 1.9–3.9%, respectively. To evaluate the accuracy of this method, cucumber, cauliflower, spinach, and carrot samples spiked with acephate and isocarbophos were extracted and analyzed with good recoveries from 76.8 to 88.8%. This method was then verified by gas chromatography method.

PurposeThe purpose of this paper is to examine the effects of managerial decision horizon (MDH) on real estate investment trust (REIT) behavior and performance.Design/methodology/approachIn this study, the authors expand the number of proxies and measure managerial horizon by CEO age, CEO tenure, cash compensation relative to total compensation, and the amount of vested equity-based compensation to total compensation. To avoid potential measurement error, the authors compute the average ranking score of the four individual measures to determine the overall MDH of a CEO. Cross-sectional time series regressions are then performed on the effects of CEO MDH on REIT policies and performance. The authors also examine if the effect of myopic MDH can be mitigated by good corporate governance. For robustness purpose, the authors also compare the effects of age-related MDH and compensation-related MDH.FindingsThe results show that REITs managed by CEOs with short MDHs have lower levels of asset growth and a lower standard deviation of return on assets. These REITs also have lower debt levels, lower dividend payouts, and hold more cash. The results suggest that short-horizon CEOs have incentives to lower investment risk, default risk, and liquidity risk at the firm level in order to protect personal benefits. CEOs with a short horizon also have a negative impact on REIT performance. The results also show that CEO compensation-related horizon problems are mitigated by corporate governance, but CEO age-related horizon problems are significant and persistent. The results suggest that age-related behavioral biases of the CEO are important determinants of corporate decisions.Practical implicationsThe results of this study suggest that the managerial behavioral biases should be considered in understanding firm behavior.Originality/valueThis is the first study that examines the effects of MDH on REIT behavior and performance. The unique regulatory environment of REITs makes them less susceptible to agency problems of free cash flow and thus provides a clearer picture of the effect of MDH. Prior studies focus on the effect of managerial horizon on firm investment activity, this study expands the scope to examine the effects on investment and financial policies. In addition, this study adds to the literature by showing that the effect of age-related horizon problems may not be mitigated by good corporate governance.

We introduce hesitance degree of hesitant fuzzy element.We propose novel distance between hesitant fuzzy sets.We propose novel similarity measures between hesitant fuzzy sets.We apply our similarity measure in pattern recognition. In this paper, we take into account the hesitance degree of hesitant fuzzy sets, introduce the concept of hesitance degree of hesitant fuzzy element which describes the decision makers hesitance in decision making process, and propose several novel distance and similarity measures between hesitant fuzzy sets. A comparison with the existing distance and similarity measures between hesitant fuzzy sets and a numerical example show that our proposed method is reasonable and valid.

High-frequency trading (HFT) has continuously evolved and dominated trading in the past decades. However, HFT trading marker prediction is a rarely investigated problem in Fintech literature. In this study, we first propose a novel manifold learning based HFT trading marker prediction model: M-SCAN to handle this challenge. Our study takes advantage of manifold embeddings of HFT data and seeks potential markers among the outliers in density-based clustering. We further propose HFT trading marker evaluation algorithms to validate the prediction effectiveness besides unveiling trading marker discovery via visualization. Our results demonstrate locally linear embedding (LLE) outperforms its peers in capturing trading markers in terms of accuracy and complexity for its local data structure keeping mechanism in embedding though different stocks may demonstrate their model preference under M-SCAN. Our studies also propose novel entropy and variance concentration ratios (VCR) to quantify HFT data and show that a high-entropy dataset is more likely to have better trading marker prediction than a low-entropy one. To the best of our knowledge, it is the first study in HFT trading marker prediction and will inspire coming studies in this area.

In this study, a novel molecularly imprinted polymer (MIL@MIP) that could selectively recognize the trichlorfon and monocrotophos was synthesized using metal-organic framework MIL-101 as support material. The prepared MIL@MIP was characterized by Fourier transform infrared, thermogravimetric analysis, scanning electron microscope, static adsorption, kinetic adsorption, and competitive adsorption analyses. Using this material as sorbent, a new method of molecularly imprinted solid-phase extraction coupled with high performance liquid chromatography for simultaneous determination of trichlorfon and monocrotophos was established. Under optimal conditions, the limit of detection (LOD) of this method for trichlorfon and monocrotophos detection was 0.011 and 0.015 mg/kg, respectively. The relative standard deviation (RSD) for five replicates of 0.05 mg/L trichlorfon and monocrotophos mixed solutions was within the range of 1.8 to 3.7 %. Apple and pear samples spiked with the two kinds of organophosphate pesticides were extracted and determined by using this method with good recoveries ranging from 86.5 to 91.7 %. Moreover, this method was successfully applied for the detection of the two organophosphate pesticides in strawberry samples.

In this paper, we introduce the summing-type and multiplying-type decomposable balance function, discuss their properties in detail, and investigate the effectiveness of the balance function for the orness measure of variable weight vector and for the factor weights. These results will be used to provide some principles for selecting the balance function in decision making and support systems.

In this study, a magnetic molecularly imprinted polymer (MMIP) based on Fe3O4@SiO2@CdTe (CdTe@MMIP) was synthesized using trichlorfon as template molecule, methacrylic acid (MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The prepared MMIP was characterized, and the results showed that it exhibited good recognition and selective ability, offered a faster kinetics for the adsorption of trichlorfon. Scatchard analysis indicated that the binding sites in the CdTe@MMIP had two distinct groups (the high and low affinity binding sites). The saturated adsorption capacity (Qmax1) was 63.2 mg/g due to the low affinity binding sites, and another saturated adsorption capacity (Qmax2) was 71.4 mg/g due to the high affinity binding sites. Using it as sorbent, a method of molecularly imprinted magnetic solid-phase extraction coupled with capillary electrophoresis (MIMSPE-CE) for selective extraction, magnetic separation, and fast determination of trace trichlorfon in vegetable samples was developed. Under optimal conditions, appreciable sensitivity was achieved with a LOD of 30 μg/kg (S/N = 3) for the developed method. The relative standard deviation (RSD) for five replicate extractions of 0.05 mg/L trichlorfon standard solution was 4.2%. To evaluate the accuracy of this method, the blank cucumber and cauliflower samples spiked with trichlorfon were extracted and analyzed by this method with good recoveries ranging from 78.7% to 96.6%. Moreover, this method was applied to the quantitative detection of the trichlorfon residues in rape samples, and the results correlated well with that obtained from the gas chromatography method.

The Bonferroni mean has been extensively applied in multicriteria decision-making and support system and developed intuitionistic fuzzy set theory. Based on the second interpretation of the Bonferroni mean, in this paper, we introduce the geometric Bonferroni mean, which is a generalization of the Bonferroni mean and geometric mean and generalized geometric Bonferroni mean, and investigate their properties. To describe the uncertainty and fuzziness more objectively, we further develop the intuitionistic fuzzy geometric Bonferroni mean and the generalized intuitionistic fuzzy geometric Bonferroni mean, which describe the relationship between arguments, and the weighted intuitionistic fuzzy geometric Bonferroni mean and the generalized weighted intuitionistic fuzzy geometric Bonferroni mean, which consider the importance of each argument. Finally, we investigate their properties in detail.