Dual Method Research Articles

Probabilistic dual hesitant fuzzy MAGDM method based on generalized extended power average operator and its application to online teaching platform supplier selection

Probabilistic dual hesitation fuzzy set (PDHFS) is a new tool used to enhance fuzzy and imprecise information in a changing and complex decision-making environment. Compared with the existing fuzzy sets, PDHFS is more suitable for identifying uncertain evaluation data in complex and realistic decision-making situations. The extended power average (EPA) and generalized power average (GPA) operators provide more information for the information aggregation process, reflecting the mutual support among all aggregation values. To solve the evaluation problems related to decision analysis involving extremely complex information, especially in the case of extreme data in the consideration of decision problems. In this paper, the generalized extended power average (GEPA) operator is proposed in the PDHF environment. This research has the following four important contributions. First, we propose a probability splitting algorithm of normalizing PDHFE, and give some new basic operations, score function, distance measures and aggregation operators. Second, to better integrate the advantages of EPA and GPA operators, we developed the GEPA operator, weighted form (WGEPA) and ordered form (GEPOWA). Meanwhile, by adjusting the parameter in three types of operators, we can find that many existing operators are special forms of the three types of operators. Third, extended the three types of operators to the PDHF environment, the PDHFGEPA, PDHFWGEPA, PDHFGEPOWA operators and some special aggregation operators are obtained, and studied their valuable properties in detail. Finally, taking the application of PDHFWGEPA operator as an example, a new multi-attribute group decision-making (MAGDM) technique is developed and used to solve the problem of online teaching platform supplier selection (OTPSS). Through parameter sensitivity analysis, the flexibility and stability of MAGDM technique are illustrated, and compared with some existing decision-making methods, the effectiveness of MAGDM method is proved. In addition, this technique also provides some theoretical references for dealing with other complex MAGDM problems, and provides a new operator for the extension of GEPA operator in other fuzzy environments. The biggest advantage of several operators is that they can pay full attention to the special role of extreme data in decision-making.

Band structures analysis of fluid–solid phononic crystals using wavelet‐based boundary element method and frequency‐independent fundamental solutions

AbstractA novel method of combination of wavelet‐based boundary element method (WBEM) with frequency‐independent fundamental solutions is proposed to determine the band structures of fluid–solid phononic crystals (PCs) with square and triangular lattices. Integral equations established are based on the frequency‐independent fundamental solutions, which can avoid nonlinear eigenvalue problems and reduce computing time. Domain integral terms arising from the use of frequency‐independent fundamental solutions are handled with the radial integration method (RIM) and dual reciprocity method (DRM), respectively. The results show the lower precision in high frequency domain of using RIM to handle domain integral terms than that of using DRM, which can be solved by increasing Gauss point. The B‐spline wavelet on the interval and wavelet coefficients are applied to approximate the physical boundary conditions. It is proved that coupling conditions between matrix and scatterers and Bloch theorem are also applicable to wavelet coefficients. Some small matrix entries generated by wavelet vanishing moment characteristics are truncated by the provided matrix compression technique, and the influence of compressed matrices on the results is studied. Furthermore, the final Eigen equations constructed are modified to avoid numerical instability. Some examples are provided to demonstrate the accuracy and efficiency of the proposed method.

A Method for tackling multiplicity in dynamic flux balance models by an ellipsoidal reflection operation

Dynamic Flux Balance Models (DFBM) can describe the evolution of metabolites’ concentrations with time by solving a linear programming (LP) problem at each time interval. However, since multiple solutions of the LP commonly exist, different trajectories can be obtained. An interior-point based method (weighted primal–dual method) proposed in a previous study that picks a specific solution from multiple solutions of LP is computationally expensive for a large metabolic network. In this research, we propose an alternative computationally efficient method based on an ellipsoidal reflection mathematical operation. The method is applied to different examples to demonstrate the algorithm and its computational efficiency and then for modeling the fermentation of B. pertussis resulting in excellent computational performance and accurate fitting of experimental dynamic data.

Assessing the effectiveness of targeted poverty alleviation policies in Xinjiang, China

To consolidate and expand the effective connection between the achievements of poverty alleviation in Xinjiang’s deeply impoverished areas and rural revitalization, it is necessary to study the effects and mechanisms of poverty alleviation policies. In this paper, the value of night light is used to measure regional economic development, and the panel data of 32 national key counties for poverty alleviation in Xinjiang and the remaining 48 counties in the province under its jurisdiction are analyzed by using the dual difference method to evaluate the promotion effect of poverty alleviation policies on regional economic development. The indirect impact of different poverty alleviation measures on economic development is explored by using the intermediary effect model. The study found that the implementation of the policy significantly promoted the development of the county economy, and the poverty alleviation policy in minority counties in the region had a stronger role in promoting the economy than that in nonminority counties. Further analysis of the mechanism shows that industrial poverty alleviation and education poverty alleviation have a significant role in county economic development, and the promotion of education poverty alleviation is lower than that of industry poverty alleviation.

Understanding the solid/liquid interface evolution during the dissolution of Nd-doped UO2 by macro-/microscopic dual approach

The chemical durability of Nd-doped UO2 samples was studied using an innovative macro-/microscopic dual approach method. The starting precursor was first prepared by a hydroxide co-precipitation route leading to a nano-sized powder associated to high specific surface area. The powder was then converted into U0.8Nd0.2O2±y solid solution by calcination. After shaping of the oxide powder into the pellet form through uniaxial pressing at 500 MPa, the pellets were sintered at 1600 °C under inert (Ar) or reducing (Ar-4%H2) atmosphere. At the macroscopic scale, multiparametric dissolution tests were carried out under static conditions in 2 mol.L−1 HNO3 at 60 °C. Simultaneously, an operando monitoring of the solid/liquid interface evolution during dissolution was also performed by ESEM at the microscopic scale, in order to follow the consequences of the dissolution on the ceramics microstructure. This dual approach was validated by comparing the calculated normalized dissolution rates obtained for each series of experiments. Changing the sintering atmosphere did not appear to significantly affect the dissolution kinetics of Nd-doped UO2 samples at the macroscopic scale whereas notorious differences in the dissolution mechanisms have been highlighted at the microscopic scale by ESEM monitoring solid/liquid interface.

4f photoabsorption in Pt+ to Pt4+

Detailed knowledge of the inner-shell atomic structure of lowly-ionised species is lacking for most elements along the sixth row of the periodic table, from hafnium to bismuth. This paper presents 4f-photoabsorption spectra of Pt+ to Pt4+ ions, recorded between 69 and 127 eV (9.8 nm and 18 nm) using the dual laser plasma method. Analysis of the spectra was supported by atomic structure calculations using the Cowan suite of codes, by relativistic time-dependent local-density approximation (RTDLDA) calculations, and by comparison along isoelectronic series, particularly with spectra of lowly-ionised gold plasmas. The RTDLDA calculations account for the influence of photoionisation and photoexcitation on the recorded spectra. The spectra show 4f 5d, 6d, and 7d transitions, broadened by autoionisation.

Achieving Material and Energy Dual Circulations of Spent Lithium‐Ion Batteries via Triboelectric Nanogenerator

AbstractThe electrification of transportation in the past few decades has sparked the retirement of lithium‐ion batteries (LIBs) which hinders sustainability derived from environmental impact and valuable elements loss through improper disposal. The challenges of recycling spent LIB are contamination, complicated processes, massive chemical/energy consumption, and secondary pollution. Here, a material and energy dual circulations method is proposed for a closed‐loop and sustainably recycling the components in spent LIBs. In the material circulation, the cathode, anode, and the accessories, like castings, aluminum‐plastic films, and binders, are recycled by electrochemical dual‐electrode recycling technology to regenerate LIBs and fabricate a triboelectric nanogenerator (TENG). In energy circulation, the fabricated TENG converts ambient wind energy into electricity to continuously power the material circulation by forming a self‐powered system. This system shows high element selectivity (Li, 99.7%; Ni, 96.1%; Co, 97.3%; and Mn, 97.2%), self‐powering, a simplified treating procedure, and high profit, which makes it feasible for commercial application.

RED WoLF hybrid energy storage system: Algorithm case study and green competition between storage heaters and heat pump

Green house gases reduction is critical in current climate emergency and was declared as major target by United Nations. This manuscript proposes the progressive adaptive recursive multi threshold control strategy for hybrid energy storage system that combines thermal storage reservoirs, heat pumps, storage heaters, photovoltaic array and a battery. The newest control strategy is tested in numerical experiment against primal dual simplex optimisation method as benchmark and previous iterations of RED WoLF threshold approaches. The proposed algorithm allows improvement in reduction of CO2 emissions by 9% comparatively to RED WoLF double threshold approach and by 26% comparatively to RED WoLF single threshold approach. Besides, the proposed technique is at least 100 times faster than linear optimisation, making the algorithm applicable to edge systems. The proposed method is later tested in numerical experiment on two measured datasets from Luxembourg school and office, equipped with batteries and ground source heat pumps. The system allows the reduction of CO2 emission and improvement of self-consumption, size reduction of the photovoltaic array installed at the facilities by at least by half as well as substituting battery storage by thermal storage, reducing the initial investment to the system. Intriguingly, despite 3.6 times difference in efficiency between heat pumps and storage heaters, the system equipped with latter have potential to achieve similar performance in carbon reduction, suggesting that energy storage have more prominent carbon reduction effect, than the power consumption, making cheaper systems with storage heaters a possible alternative to heat pumps.

UAV-Assisted Multi-Cluster Over-the-Air Computation

In this paper, we study unmanned aerial vehicles (UAVs) assisted wireless data aggregation (WDA) in multi-cluster networks, where multiple UAVs simultaneously perform different WDA tasks via over-the-air computation (AirComp) without terrestrial base stations. This work focuses on maximizing the minimum amount of WDA tasks performed by each cluster by optimizing the UAV trajectory and transceiver design as well as cluster scheduling and association, while considering the WDA accuracy requirement. Such a joint design is critical for interference management in multi-cluster AirComp networks, via enhancing the signal quality between each UAV and its associated cluster for signal alignment while reducing the inter-cluster interference between each UAV and its non-associated clusters. Although it is generally challenging to optimally solve the formulated non-convex mixed-integer nonlinear programming, an efficient iterative algorithm as a compromise approach is developed by exploiting bisection and block coordinate descent methods, yielding an optimal transceiver solution in each iteration. The optimal binary variables and a suboptimal trajectory are obtained by using the dual method and successive convex approximation, respectively. Simulations show the considerable performance gains of the proposed design over benchmarks and the superiority of deploying multiple UAVs in increasing the number of performed tasks while reducing access delays.

Study of Streptomyces spp. to control purple blotch disease caused by Alternaria porri in shallot plant

Alternaria porri is a fungal pathogen that causes purple blotch on shallots, this fungus can cause crop yield loss of 3 – 57%. A. porri was obtained from the Sumber Brantas onion farm and then isolated by planting infected tissue. Streptomyces spp. is a filamentous bacterium that is abundant in the soil and can be used as a biological agent, decomposer and plant growth promote. Streptomyces spp. was obtained one isolate from shallot land location in Pare, Kediri, East Java (BMP: Bawang Merah Pare) and three isolates from Sidera, Palu, Central Sulawesi (BMS: Bawang Merah Sidera) (BMS1, BMS2, BMS3). The purpose of this study was to determine the efficacy of Streptomyces spp. to control A porri consist of in vitro and In vivo antagonist test. Antagonist test was carried out by dual culture method and the Streptomyces spp. which can inhibit the development of A porri would be used antagonist test in vivo. The study was designed using a Factorial Complete Randomized Design with two factors, candidate isolates of biological control agents and concentrations of Streptomyces spp. be diluted into 5%, 10%, and 15%, it will applied on shallot plant Bauji variety. The results of the In vitro test shown the highest inhibition zone from BMP 17.75% while BMS1 13.75%, BMS2 8,75%, and 8.50%. in vivo test shown lowest disease severity value in BMP 15% concentration was 1.13% while diseases severity of BMS1 was 1.27%, and BMS2 was 1.80%. Therefore, Streptomyces spp. has potency as an alternative pesticide for sustainable agriculture.

Regularization Strategy Aided Robust Unsupervised Learning for Wireless Resource Allocation

Unsupervised learning (UL) is widely used in the wireless resource allocation problems due to its lower computational complexity and better performance compared with traditional optimization algorithms. Since wireless resource allocation problems usually have several constraints, primal-dual learning based UL framework are widely adopted. However, the primal-dual learning approach has the problem of oscillation around the constraint threshold while training and there may be serious constraint violations when deployment. In addition, although the output of the neural network can also be restricted to the feasible region by the penalty function method, the optimality of such training methods cannot be guaranteed. In this paper, we combine the primal dual learning method with the penalty function method and propose a regularized unsupervised learning (RUL) framework to enhance the robustness of the primal-dual learning based UL framework. In the proposed RUL framework, we use regularization techniques to improve the robustness of primal-dual learning by reducing the risk of constraint violations while training. A quadratic penalty term is introduced into the Lagrangian function of the wireless optimization problem where the constraints can be equivalent to equality constraints to form its augmented Lagrangian function. In the simulation, we give a simple point to point power optimization problem as an example to show that the proposed RUL can improve the robustness of constraint convergence, and can also accelerate training speed.

Dual-Circulant Modulation for Modular Multilevel DC/DC Converters With Inherent Balance Capability

Modular multilevel DC/DC converters (MMDC) have emerged recently for medium-voltage dc applications. Under single circulant modulation, the sub-module (SM) capacitor voltages in MMDC are found to be evenly divided only at some specific modulation coefficients. To obtain the inherent balance capability under all modulation coefficients and expand the application range of circulant modulation, a simple dual circulant modulation is proposed in this letter. On the basis of single circulant modulation, the self-balancing of the SM capacitor voltages is realized by using the additional switching patterns generated by a simple circulant permutation method. The theoretical analysis of the proposed method is presented, and the inherent balance capability of MMDC under the dual circulant modulation method is verified by experiments.

Mechanical Behavior of Hybrid Laminated Nano Composite Containing Equal Numbers of Glass and Carbon Fiber Plies

Hybrid fiber reinforced polymer with nanofiller composite was introduced into a lot of industries due to its extreme mechanical properties in comparison with non-hybrid material. In this investigation, cross and quasi-fiber laminated epoxy composites with and without nano Al2O3 were fabricated using Vacuum Assisted Resine Infusion Method and Ultrasonic Dual Mixing Method. In general, the results of mechanical properties indicated that the addition of 2% nano Al2O3 enhances the tensile and flexural properties. Cross number 2 with nano Al2O3 laminate had the maximum tensile strength 628 MPa and maximum tensile strain of 1.74%, while cross number 1 with nano Al2O3 laminate had the maximum tensile modulus of 37.756 GPa in the cross group. In the quasi group, quasi number 2 with nano Al2O3 had the maximum tensile strength, maximum tensile strain, and maximum tensile modulus, equal to 294 MPa, 1.98%, and 16.409 GPa, respectively. Regarding the flexural properties, cross number 1 with nano Al2O3 laminate had a maximum flexural strength of 708.2 MPa and maximum flexural strain of 2.027%, while cross number 2 with nano Al2O3 laminate had a maximum flexural modulus of 38.73 GPa in the cross group. On the other hand, quasi number 1 with nano Al2O3 laminate had the maximum flexural strength, maximum flexural strain, and maximum flexural modulus equal to 596 MPa, 2.424%, and 29.2 GPa, respectively in the quasi group. The internal structures of the failure laminated composites through scanning electronic microscopy confirm that the adhesion between fibers and matrix is good.

Collapse risk-targeted seismic design of concrete-filled steel tube frame-RC core tube structures

The concrete-filled steel tube (CFST) frame-reinforced concrete (RC) core tube composite structure is a widely-used structural system of high-rise buildings due to its high compressive strength, good plasticity, and convenient construction. The cross-sectional dimensions and bending stiffness of CFST frames are smaller than those of RC frames with the same vertical load-bearing capacity. Since the seismic forces are distributed in proportion to stiffness for components, the assigned seismic forces of CFST frames are smaller, which may result in CFST frames not meeting the minimum load-bearing capacity requirement for the frame part in a dual system. If the CFST frame-core tube structure is designed adopting the dual system seismic design method which is applicable to RC frame-core tube structure, forcefully increasing the design seismic force of the frame, this will significantly increase the amount of material consumed and reduce the available area of the building. In this study, the CFST frame-RC core tube structure is designed according to different seismic design methods and compared through incremental dynamic analysis-based (IDA) fragility analysis. Then, an improved collapse risk-targeted seismic design method is proposed. The study results indicate that the structure designed according to the proposed method can achieve the excellent collapse resistance capacity, low collapse probability, and less material cost, which may provide a reference for seismic design of CFST frame-RC core tube composite structures.

Using dual stable isotopes method for nitrate sources identification in Cao-E River Basin, Eastern China

Excess nitrate (NO3−) of water is a worldwide environmental problem. Therefore, identifying the sources and analyzing respective contribution rates are of great importance for improving water quality. The current study was carried out to identify the potential sources of NO3− pollution in Cao-E River basin, in Eastern China. Surface water samples were collected during the dry season and wet season. Multiple hydrochemical indices, dual NO3− isotopes (δ15N–NO3− and δ18O–NO3−) and a Bayesian model (stable isotope analysis in R, MixSIAR) were applied to identify NO3− sources and estimate the proportional contributions of multiple NO3− sources. During the sampling period, nitrification was a dominant nitrogen transformation process in the study area. The results of the NO3− isotopes suggested that manure and sewage (M&S), soil nitrogen (SN) and nitrogen fertilizer (NF) were the major contributors to NO3−. Moreover, the results obtained from the MixSIAR model showed that the proportional contributions of atmospheric deposition (AD), NF, M&S and SN to NO3− were 2.82, 15.45, 44.25, 37.47% and 3.14, 23.39, 31.78, 41.69% in the dry and wet season, respectively. This study provided evidence to further understand the sources, transport, and transformation of N in Cao-E River basin, which deepens the understanding of the management of N contaminant.

Contributing Factors to Low Uptake of Female Condoms among Child- Bearing Age Woman using Family Planning at Engela State Hospital, Namibia

The advent of the female condom was hailed as an appropriate intervention measure against the spread of sexually transmitted infections and HIV. The female condom is an effective dual protective method viewed as a tool for woman’s empowerment, though the supply and uptake of this device are limited. This study determined and described the factors that have resulted in the low uptake of female condoms at Engela State Hospital among child- bearing age woman. A quantitative-descriptive research was used on the population of mothers utilizing health services at Engela clinic. Convenience sampling was used to select 52 respondents that participated in the study. Data was collected by means of questions and analysed by using Microsoft Excel 2016. The results showed that the factor leading to the low rate of female condom use was the absence of female condoms in hospitals and the community, rather than male condoms (80.8%) They are difficult to use (88.5%), married women are often powerless to request their partner to wear a condom (84.6%), women prefer the use of male condom than the female condom (88.5%), people are used to using male condom than the female condom (88.5%) and female condoms increase sexual pleasure (88.5%). It was concluded that in Engela State Hospital, a variety of factors influence the use of the Female Condom by women of reproductive age. Therefore, the Namibian government, through the Ministry of Health and Social Services, should implement intensive interventions such as the provision of Information Education and Communication materials and broad peer education. Moreover, The Namibian government, through the Ministry of Health, should study the findings of global research on the use of FCs and use these findings to build a strategic plan to guarantee that FCs are used effectively.

Anti-icing characteristics of hierarchical micro-dimple textured surface generated by 3D resonant vibration assisted machining

Anti-icing techniques are essential for safe functioning in applications such as aircraft and power transmission lines. In the present study, a long lasting and minimal maintenance required hierarchical micro-dimple surface textures were produced on a cylindrical specimen using a dual frequency surface texturing method. The water contact angle and time delay in freezing on five diverse type of micro-dimples with three different surface texture densities and non-textured surfaces were examined and compared experimentally. The textured surfaces showed an approximately 28 % increase in delayed time compared to non-textured surfaces. A size effect on the performance of micro-dimples was observed. Smaller size micro-dimples have better delayed time for higher texture density surfaces. The delayed time increases with the increase in micro-dimple size for optimum and low texture density surfaces. Introducing of hierarchical structures increased the delayed time by 8 % compared to single scale micro-dimple surface textures. The idea of introducing hierarchical micro-dimples as an anti-icing technique will directly result in improving the delayed time, which in turn reduces the load on the secondary system for ice removing and improves its working efficiency.

Effect of rice rhizospheric Trichoderma spp and fungicide for the management of brown spot disease of rice

Brown spot of rice caused by Bipolaris oryzae is of worldwide occurrence and is known to cause substantial quantitative and qualitative losses in grain yield. This disease was responsible for the epic 'Great Bengal Famine' in 1942-1943, resulting in the death of 4 million people. Studies were carried out to evaluate the effect of rice rhizospheric Trichoderma spp and fungicide for the management of brown spot disease of rice. A total of 20 isolates of Trichoderma spp were isolated from rice rhizospheric soil and screened by dual culture method in which three isolates Ti20, Ti19 and Ti16 showing maximum inhibition of 67.86%, 64.29% and 60.71% were selected for further test. Six fungicides viz., Hexaconazole, Propiconazole, Carbendazim + Mancozeb, Metalaxyl + Mancozeb, Carbendazim and Copper oxychloride were evaluated against B. oryzae by poison food technique, out of which Propiconazole, Hexaconazole and Copper oxychloride were selected and further tested for their compatibility with the selected Trichoderma spp was done. The most efficient and compatible Trichoderma sp with fungicide i.e., (Ti19 + Hexaconazole 5% SC) were selected for managing the disease in pot experiment with different treatment combinations i.e., seed treatment, seedling dip and foliar spray. Results under pot experiment showed that, seed treatment with Ti19 and Hexaconazole 5% SC recorded lowest disease severity of 3.70%, 7.41% and 11.11% at tillering, booting and milking stages respectively, with significantly higher yield of 28.27 g/pot as compared to untreated control pots.

Modeling and motion control of helical microrobots using the dual quaternion framework and adaptive sliding mode strategy

This study investigates the tracking control problem of helical microrobots (HMRs) in complicated blood environments. The integrated relative motion model of HMRs is established by resorting to the dual quaternion method, which can describe the coupling effect between the rotational and translational motions. Subsequently, an original apparent weight compensator (AWC) is designed to alleviate the adverse effects of the HMR sinking and drifting owing to its own weight and buoyancy. An adaptive sliding mode control based on the developed AWC (AWC-ASMC) is constructed to guarantee the fast convergence of the relative motion tracking errors in the presence of model uncertainties and unknown perturbations. The chattering phenomenon of the classical SMC is significantly reduced using the developed control strategy. Furthermore, the stability of the closed-loop system under the constructed control framework is demonstrated by the Lyapunov theory. Finally, numerical simulations are performed to demonstrate the validity and superiority of the developed control scheme.

Reducing the low-wavenumber dispersion error by building the Lagrange dual problem with a powerful local restriction

Abstract The broadband finite-difference (FD) coefficients computed by a cost function have been widely applied to suppress of numerical dispersion. Under the same conditions, the FD coefficients with small low-wavenumber dispersion error will produce a more accurate numerical solution in the long-time seismic wave simulation. Thus, how to reduce the low-wavenumber dispersion error becomes a crucial problem. According to the research into the zero-point position at the dispersion curve for three types of cost function, we found that the more zero points concentrate on the low-wavenumber region, the less the dispersion error. Therefore, the concentration of zero points is a good way to reduce dispersion error, which can be implemented by modified wavenumbers of zero points. Then, we design a Lagrange dual problem with a restriction based on the modified wavenumbers. The requirements for constructing the Lagrange dual problem are the optimization function and restricted condition, where the former is based on the dispersion relation, and the latter comprises the modified wavenumbers. The solution of this optimization problem, calculated by the dual ascent method, affords a less low-wavenumber dispersion error than the solution yielded by the alternating direction method of multipliers (ADMM). The theoretical analysis and numerical modeling suggest that the proposed method is superior to the existing optimal FD coefficients in reducing numerical error accumulation in low-frequency simulation.