Outlier identification and group satisfaction of rating experts: density-based spatial clustering of applications with noise based on multi-objective large-scale group decision-making evaluation

Group satisfaction is a trending issue in large-scale group decision- making (LSGDM) but most existing studies maximize the group satisfaction of LSGDM from the perspective of consensus. However, the clustering algorithm in LSGDM also has an impact on group satisfaction. Hence, this paper proposes a density-based spatial clustering of applications with noise (DBSCAN)-based LSGDM approach in an intuitionistic fuzzy set (IFS) environment. The DBSCAN algorithm is used to identify experts with outlier ratings that can reduce the time consumption and iterations of the LSGDM process and maximize the satisfaction of the group decision. An easy-to-use function is then provided to estimate group satisfaction. Finally, a numerical example of data centre supplier evaluation and comparative analysis is constructed to validate the rationality and feasibility of the proposed DBSCAN-based LSGDM approach in an IFS environment. The results demonstrate that the proposed method can effectively identify outliers in expert ratings and improve group satisfaction in the LSGDM process

Adaptive Concentration Inequalities for Sequential Decision Problems

Abstract A key challenge in sequential decision problems is to determine how many samples are needed for an agent to make reliable decisions with good probabilistic guarantees. We introduce Hoeffding-like concentration inequalities that hold for a random, adaptively chosen number of samples. Our inequalities are tight under natural assumptions and can greatly simplify the analysis of common sequential decision problems. In particular, we apply them to sequential hypothesis testing, best arm identification, and sorting. The resulting algorithms rival or exceed the state of the art both theoretically and empirically

Discovery of innovation effect and spillover effect: Evidence from intelligent manufacturing promoting low-carbon development

As global warming increases, the need for the coordinated development of the economy and the environment is becoming increasingly apparent, urgently requiring a low-carbon transition. A conceptual framework was constructed originally from the perspective of innovation and the spillover effect, exploring the influencing pathways of intelligent manufacturing on the low-carbon transition. The dynamic linkages among intelligent manufacturing, carbon efficiency, and industrial structure upgrading were demonstrated by the PVAR model, based on a panel data set of 30 provinces in China from 2006 to 2020. The empirical result shows that intelligent manufacturing promotes low-carbon transition mainly through industrial structure upgrading, and the spillover effect plays a more significant and widespread role in the low-carbon transition. Furthermore, the level of industrial structure upgrading was determined as the variable that explains the change in carbon efficiency the most according to the variance decomposition. Additionally, it is inefficient for intelligent manufacturing to popularize in traditional industries, which implies that it should be taken as a step-by-step approach to achieve a low-carbon transition for traditional industries. Moreover, upgrading the industry structure is an important step with far more priority in a low-carbon transition

Numerical investigation of oblique detonation waves on a truncated cone in hydrogen-air mixtures

Traditional methods of initiating oblique detonation waves (ODWs) using wedges and cones face a fundamental challenge in reconciling the need for rapid initiation with stable combustion, especially at low flight Mach numbers (Ma < 8). This study introduces an innovative initiation configuration involving a truncated cone. By utilizing Euler equations coupled with detailed hydrogen-air chemical reaction models, the wave dynamics induced by the truncated cone configuration are systematically explored. The findings reveal that the truncated cone configuration enables more rapid initiation of ODWs compared to conventional cones, while also preserving improved stability when contrasted with wedge. This behavior can be attributed to the planar flow characteristics in the post-shock field of truncated cone, generated by the upstream wedge-shaped shock, and the Taylor-Maccoll flow characteristics, caused by the downstream conical shock. Furthermore, the study delves into the initiation and morphological changes with respect to the inner radius and angle of the truncated cone. As inner radii or truncated cone angle increase, three initiation wave systems emerge: stable, oscillatory, and detached modes. Analysis of the dynamic variations in pressure and velocity within the induction zone highlights that the upstream oscillation originates from the flow velocity in the induction zone falling below the local Chapman-Jouguet velocity of normal detonation wave (NDW). However, the upstream region of the truncated cone exhibits more pronounced expansion effects, leading to momentum loss, and subsequently, the weakening and even vanishing of the NDW. This prompts the downstream oscillation of the initiation structure, instigating a cyclic oscillation pattern

S-matrix positivity without Lorentz invariance: a case study

Abstract We investigate the analytic structure of scattering amplitudes in theories in which Lorentz invariance is spontaneously broken. We do so by computing and studying the S-matrix for a simple example: a superfluid described by a complex scalar with quartic interactions. The computation is confined to tree-level, for there are no absolutely stable single-particle states, though the lifetime can be made long by lowering the chemical potential. For the 2 → 2 amplitude in center-of-mass configurations, not only is crossing symmetry violated, there appears a tree level branch cut for unphysical kinematics. Its appearance is a consequence of non-analyticity in the dispersion relation. The branch point defines a new scale in the problem, which scales inversely with the chemical potential. In this example, even derivatives of the forward amplitude are positive while odd derivatives are negative. This pattern can be understood in a general way in the limit of a small chemical potential, or weak Lorentz breaking

Synergy of devulcanized rubber and rock asphalt for asphalt modification

Rock asphalt (RA) has gradually been recognized as a green and efficient asphalt modifier. However, the weakness of low-temperature performance and fatigue resistance for RA modified asphalt limited its application and popularization in asphalt pavement. To overcome the above shortcomings, this study aimed to synergistically apply devulcanized rubber powder (DRP) with American rock asphalt (ARA) for asphalt modification. Multiple experiments such as dynamic shear rheology (DSR) and bending beam rheology (BBR) were conducted to evaluate the rheological properties and road performance of composite modified asphalt (CMA). Cigar tube test (CTT) was applied to assess storage stability of CMA. In addition, Fourier transform infrared spectrometer (FTIR) and microscopic test (MT) were used to investigate the modification mechanisms. The results showed that CMA modified by DRP and ARA exhibited comparable storage stability, low-temperature performance and rutting resistance as SBS modified asphalt. ARA tended to cause aging problems of asphalt, but the addition of DRP effectively improved the aging resistance performance of modified binder blends, especially long-term aging resistance. The mixing of DRP, ARA and base asphalt is a physical process without chemical reactions. Even though the ash in ARA slightly lowered its storage stability, it significantly improved dispersion and homogenous interface of DRP in asphalt

Analysis of the Odor Purification Mechanism and Smoke Release of Warm-Mixed Rubber Asphalt

This study focuses on the common key technologies of “environmentally friendly and resource-saving” asphalt pavement. Reactive asphalt deodorizers react with volatile chemicals with irritating odors in asphalt under high temperature conditions, converting them into stable and non-volatile macromolecules to remove odors and achieve a deodorizing effect. A goal is to develop clean asphalt pavement materials with the main characteristics of “low consumption, low emissions, low pollution, high efficiency”. In this experimental research, we used gas-emission detection devices and methods to detect and evaluate odor concentration, SO2, NO, volatile organic compounds, and other gases and volatile substances in the production and construction of clean asphalt and mixtures. By combining rheological experiments, mechanical experiments, and other means, this study investigates the effects of odor enhancers on the penetration, ductility, softening point, high-temperature rheological properties, construction, and workability of warm-mix asphalt and mixtures. Furthermore, infrared spectroscopy experiments are used to conduct in-depth research on the odor-enhancing mechanism of odor enhancers. The results indicate that the addition of odor enhancers has little effect on the penetration and softening point of asphalt and maintains the basic performance stability of asphalt. In terms of high-temperature rheological properties and construction workability, the addition of warm-mix agents has a significant impact on the high-temperature failure temperature and rotational viscosity of asphalt, while the influence of deodorizers is relatively small. At higher temperatures, the rotational viscosity increases with the increase in the amount of deodorant added. Functional group analysis shows that the newly added materials have little effect on the essential properties and chemical composition of asphalt. In addition, during the experimental process, it was found that the coupling effect and other chemical reactions between the deodorizing agent and the warm-mixing agent can effectively improve the degradation effect of harmful gases. After the coupling action of deodorant and the warm-mixing agent, the degradation rate of harmful gas can be increased by 5–20%, ensuring the stable performance of asphalt. The performance of powder deodorizing agent is better than that of liquid deodorizing agent, and an increase in the dosage of deodorizing agent will enhance the degradation effect. This study provides an important basis for a deeper understanding of the performance of warm-mix and odorless modified asphalt