Analysis of retailers’ coalition stability for supply chain based on LCS and stable set

To attain the general form of stable coalition structure, this paper addressed the problem of retailers’ coalition stability in a two-stage supply chain consisting of one supplier and multiple retailers. A profit gain function was established via introducing market gain coefficient and coalition cost coefficient for different coalition structures. Based on the function, the profit of each retailer in all kinds of coalition structures was analysed, and the general feature of a stable coalition structure was attained by the largest consistent set method and the stable set method. Furthermore, some insights were obtained. For example, stable coalition structures are equidistributed or approximate equidistributed; with supplier’s cost increasing, the size of the retailers’ coalition increases. Finally, the above conclusions are verified by numerical simulation. The results of this paper provide a reference for retailers’ coalition in a supply chain, such as automobile or Information Technology supply chain.     

Designing a multi-service healthcare network based on the impact of patients’ flow among medical services

OR Spectrum - Efficient location of medical services is an issue of paramount importance in healthcare strategic planning. In this research, a mathematical model is developed for the location of...     

Rational design of high-entropy ceramics based on machine learning – A critical review

High-entropy materials provide a versatile platform for the rational design of novel candidates with exotic performances. Recently, it has been demonstrated that high-entropy ceramics (HECs), depending on their compositions, show great application potential because of their superior structural and functional properties. However, the immense phase space behind HECs significantly hinders the efficient design and exploitation of high-performance HECs through traditional trial-and-error experiments and expensive ab-initio calculations. Machine learning (ML), on the other hand, has become a popular approach to accelerate the discovery of HECs and screen HECs with exceptional properties. In this article, we review the recent progress of ML applications in discovering and designing novel HECs, including carbides, nitrides, borides, and oxides. We thoroughly discuss different ingredients that are involved in ML applications in HECs, including data collection, feature engineering, model refinement, and prediction performance improvement. We finally provide an outlook on the challenges and development directions of future ML models for HEC predictions.     

A label‐based information flow control model for object‐oriented systems

Abstract

This paper proposes a label‐based information flow control model to prevent information leakage within object‐oriented systems. It offers the features of: (a) adapting to dynamic object state change, (b) adapting to dynamic role change, (c) preventing indirect information leakage, (d) detailing the control granularity to variables, (e) allowing purpose‐oriented method invocation, (f) controlling method invocation through argument sensitivity, (g) allowing declassification, and (h) allowing only trusted sources to write a variable.     

Macroscopic model with anisotropy based on micro–macro information

Physical experiments can characterize the elastic response of granular materials in terms of macroscopic state variables, namely volume (packing) fraction and stress, while the microstructure is not accessible and thus neglected. Here, by means of numerical simulations, we analyze dense, frictionless granular assemblies with the final goal to relate the elastic moduli to the fabric state, i.e., to microstructural averaged contact network features as contact number density and anisotropy. The particle samples are first isotropically compressed and then quasi-statically sheared under constant volume (undrained conditions). From various static, relaxed configurations at different shear strains, infinitesimal strain steps are applied to “measure” the effective elastic response; we quantify the strain needed so that no contact and structure rearrangements, i.e. plasticity, happen. Because of the anisotropy induced by shear, volumetric and deviatoric stresses and strains are cross-coupled via a single anisotropy modulus, which is proportional to the product of deviatoric fabric and bulk modulus (i.e., the isotropic fabric). Interestingly, the shear modulus of the material depends also on the actual deviatoric stress state, along with the contact configuration anisotropy. Finally, a constitutive model based on incremental evolution equations for stress and fabric is introduced. By using the previously measured dependence of the stiffness tensor (elastic moduli) on the microstructure, the theory is able to predict with good agreement the evolution of pressure, shear stress and deviatoric fabric (anisotropy) for an independent undrained cyclic shear test, including the response to reversal of strain.     

Numerical and experimental study on the flow history effects of axial flow on the Couette–Taylor flow

In this research, experimental and numerical techniques are used to study the flow history effects of axial flow on the Couette–Taylor flow. For the experimental investigation, the flow is visualized using the PIV technique with reflective particles with a density of 1.62 g/cm³. Dispersed in a solution, the particles have a strong refraction index equal to 1.85. In this study, two protocols are adopted to study the effect of an axial flow superimposed on a Couette–Taylor flow, and of the history of the flow. The first one, the direct protocol, consists of imposing an azimuthal flow to the inner cylinder. In this case, when the regime is established, the axial flow is superimposed. The second protocol, the inverse protocol, consists of imposing first the axial flow in the gap of the system, after which an azimuthal flow is conveyed. The Couette–Taylor flow with axial flow is strongly dependent on the flow history (the protocol). Thus, the flow structures and development for different protocols are studied and analyzed here experimentally and numerically. In addition, from the numerical results, mathematical models for the two protocols are presented. For the direct protocol, a new relation between the axial Reynolds number, which stabilizes the Couette–Taylor flow, and the Taylor number is presented; for the inverse protocol, a new mathematical model for the critical Taylor number is developed as a function of the axial Reynolds number and also the first critical Taylor number without axial flow.     

Vapor–liquid critical flow through a layer of spherical particles

Vapor–liquid flow in a cylindrical channel through fillings of spherical particles is studied experimentally. Data on the critical flow of a vapor–water mixture with various vapor contents through densely packed layers of spherical particles from stainless steel with diameters of 2 and 4 mm for a filling column height of 250 and 355 mm are obtained. Experimental data demonstrate the influence of pressure, the vapor content of the mixture at the input, and the geometric parameters of the filling on the critical mass velocity. The linear dependence of the critical mass velocity on the geometric factor \(\sqrt {d/H} \). The possibility of generalizing the experimental results based on the gas dynamic model for the flow of a homogeneous medium is considered.     

Evolution analysis of online topics based on ‘word-topic’ coupling network

Scientometrics - Analyzing topic evolution is an effective way to monitor the overview of topic spreading. Existing methods have focused either on the intensity evolution of topics along a timeline...     

Effect of constrained layers on vibrational characteristics of a composite sandwich system��A finite element based critical investigation

The main aim of this paper is to investigate the effect of various constrained layers (viscoelastic layer (VEL), electro-rheological fluid (ERF), and magneto-rheological fluid (MRF)) over natural frequency and the damping loss factor with two different fiber orientations (0° and 90°) for a Graphite/Epoxy (GR/E) composite sandwich shaft disc system. The finite element technique is used to investigate the natural frequency and loss factor for various combinations. Furthermore, the vibrational characteristics of the composite sandwich shaft disc system are compared with those of the base structure without constrained layers. The study shows that introducing various constrained layers reduces the magnitude of natural frequency by up to 80%. The results also show that GR/E composite with 90° fiber orientation acquires the highest frequency reduction. Among the proposed layers, VEL has the highest damping loss factor.     

LLM and X-FEM based interface modeling of fluid–thin structure interactions on a non-interface-fitted mesh

This paper presents a non-interface-fitted mesh method for fluid–thin structure interactions. The key components are the Lagrangian Lagrange-multiplier (LLM) method and the extended finite element method (X-FEM). The LLM couples fluid and thin structure through the Lagrangian nodes of the structure element. The X-FEM gives flow discontinuity to the fluid elements intersected by the structure element. The combination method is verified through applications to flow with a domain-partitioning boundary and flow-induced flapping of a flexible filament. We discuss how the discontinuities at the interface enhance the simulation results, how the lack of the discontinuities affects the results, and identify some effects of these discontinuity enrichments.     

Effect of the surface chemical groups of activated carbons on their surface adsorptivity to aromatic adsorbates based on π-π interactions

Three activated carbons with different surface chemical groups were used to analyse the influence of these groups on their adsorption capacities towards aromatic-type molecules whose adsorption is based on π-π interactions with surface arene centres. The three activated carbons studied were a low-functionalized carbon (Merck), an oxygen-rich carbon obtained by HNO₃ oxidation of Merck, and a nitrogen-rich carbon also prepared from Merck by mild HNO₃ oxidation followed by treatment with a dicyanodiamide/dimethyl formamide mixture at 300 °C. The nature of the surface chemical groups of the three activated carbons was investigated by both physical and chemical techniques (TPD, XPS, Boehm analysis and pH potentiometric titration). A systematic study of the adsorptions of a series of analogous aromatic adsorbates on the three activated carbons was carried out to study the adsorption mechanisms. In all cases the adsorption mechanism is based on π-π interactions between the aromatic moiety of the adsorbates and the arene centres of the graphite sheets. The differences in the normalized adsorption capacities of the adsorbents for a set of adsorbates indicate that the π-donor or π-withdrawing character of the functional groups have a clear influence on the basicity of the arene centres.     

Authors’ sources of information: a new dimension in information scattering

The purpose of this study is to determine the usage patterns of core journals by scholars, and to address the differences among various academic disciplines. Thus, the references of 11,230 corresponding authors for the past 35?years from the world??s top five highly cited universities and institutions were analyzed. To build robust models of information scattering, we need a deeper understanding of this phenomenon. The results show that core journals usage is a social phenomenon, in exactly the same way as Bradford??s law, Zipf??s law and Lotka??s law. The analysis of author references shows that if core scientific journals are arranged in order of decreasing productivity, then they could be divided into a small group of highly cited periodicals and a large group of minimally cited ones. Scholars may do browsing and similar information-seeking activities to form their core journals, and the findings may support Bates??s hypothesis that Bradford??s core zone is best searched by browsing. Bradford??s law and relevant research may consequently help to solve many of the practical problems that practitioners of the profession face, particularly in collection development in libraries, and help users to gather highly scattered information.     

The inventive activities and collaboration pattern of university–industry–government in China based on patent analysis

China’s economy and technology have experienced spectacular growth since the Opening-up Policy adopted in 1978. In order to explore the innovation process and development of China, this study examines the inventive activities and the collaboration pattern of university, industry and government (UIG) in China. This study analyzes the Chinese patent data retrieved from the United States Patent and Trademark Office. Three models of UIG relations which represent different triple helix configurations are introduced. According to the property of patent assignee, patent ownership can be divided into three types: individuals, enterprises, and universities and research institutes. Furthermore, enterprises can be classified into state-owned enterprise (SOE), private-owned enterprise (POE) and foreign enterprise (FE). The corresponding relationship of patent ownership with UIG is set up. Through analyzing the issued year, it is found that the inventive activities of China have experienced three developmental phases and have been promoted quickly in recent years. The achievement of innovation activities in China primarily falls on the enterprise, especially FEs and POEs. The innovation strengths of the three development phases have shifted from government to university and research institute and then industry. According to co-patent analysis, it is found that the collaboration between university and industry is the strongest and has been intensified in recent years, but other forms of collaboration among UIG have been weak. In addition, an innovation relation model of China was set up. The evolution process of innovation systems was explored, from etatistic model, followed by improved “laissez-faire” model, and then shifting toward triple helix model.     

A new Price’s estimate on the size of scientific specialties based on scientific community structure

Price argued that the average scientific specialty consists of about 100 scientists, publishing an average 100 articles each during their career. Wray recently attempted to revise the number of scientists in a specialty based on the information that the average scientist publishes only 3.5 papers during their career. However, his final estimate, between 250 and 600 scientists, does not support Price’s idea that a specialty fills about 10,000 articles, unless the ad hoc assumption is made that nearly 80 % of articles circulating in a field are from other fields. This article shows that by distinguishing between graduate students, who spend only a couple of years in a specialty, and professors, who spend their entire career in a field, the ad hoc assumption becomes unnecessary, and Wray’s number of 600 scientists turns out to be a remarkable intuitive insight that is consistent with Price’s 10,000 articles. A number of 520 scientists, or somewhat larger, is suggested for Price’s estimate.     

Identifying ‘associated-sleeping-beauties’ in ‘swan-groups’ based on small qualified datasets of physics and economics

Scientometrics - ‘Sleeping beauties’ refer to the papers that received no or scarce citation after appearance, but considerable citations several years later, which is a special...     

Real-time optimization of plug-in hybrid electric vehicles based on Pontryagin’s minimum principle

Clean Technologies and Environmental Policy - Battery aging can greatly reduce the energy efficiency of plug-in hybrid electric vehicles (PHEVs). This paper presents a novel real-time energy...     

Product low-carbon innovative design based on the carbon footprint information model北大核心CSCD

Aiming at further alleviating global warming and reducing carbon emission in product life cycle from source, low-carbon design has increasingly becoming an important direction of product design. Based on exploring the composition of decision making information and corresponding choice of design strategy in low-carbon design process, a carbon emission integrated product low-carbon design information model was established. Based on the analysis of information connotation within low-carbon design decision making, a double progressive positioning method of carbon footprint source features which was based on product structural tree and detailed design parameters was proposed, in which streamlined life cycle assessment (SLCA) using qualitative/semi-quantitative matrix approach was used to preliminarily screen the key structural units with high emission, then the key design features and parameters were stepwisely positioned by weight assigned relation digraph. With regard to design parameters related conflicts, TRIZ conflict resolution theory was used. Finally, a handled vacuum cleaner was used as an example to prove the feasibility and effectiveness of the method.