Optimized phasing conditions to avoid edge mode excitation by ICRH antennas

An ion cyclotron resonance heating (ICRH) antenna system must launch radio frequency (RF) power with a wavenumber spectrum which maximizes the coupling to the plasma. It should also ensure good absorption while minimizing the wave interaction with the plasma edge. Such interactions lead to impurity release, whose effect has been measured far from the antenna location (Klepper et al. 2013; Wukitch et al. 2017; Perkins et al. 2019) and can involve the entire scrape-off layer. In the normal heating scenario, for which the frequency of the waves launched by the antenna is larger than the ion cyclotron frequency of the majority ions $\omega > \omega _{\textrm {ci},\textrm {maj}}$ , release of impurities due to ICRH can be affected by minimizing the low $|k_{\parallel }| < k_0$ power spectrum components of the antenna. Impurity release can be the result of low central absorption of the waves or power transfer from the fast to the slow wave due to the presence of a confluence in the plasma edge. In ASDEX Upgrade (AUG), a reduction of heavy impurity release by ICRH in the plasma was qualitatively well correlated to the parallel electric field and RF currents flowing around the antenna (Bobkov et al. 2017). In this article, we first show a correlation between the reduction in impurity release by ICRH in AUG and the rejection of the low $|k_{\parallel }| < k_0$ region of the antenna power spectrum. We show that the same correlation holds for results obtained in the Alcator C-Mod tokamak. Finally, using this idea, we reproduce ICRH induced impurity release behaviour in a not yet published experiments of JET, and make predictions for ITER and DEMO.

Risks’ cross-contagion between shadow banks based on complex network theory: evidence from China

Purpose The purpose of this paper is to analyze the network path and internal mechanism of risks’ cross-contagion between shadow banks and design strategies for preventing risk infection between shadow banks. Design/methodology/approach Using the complex network theory, analyze the mechanism of risks’ cross-contagion between shadow banks from the credit network, business relationship network (BRN) and social network (SN); the cross-contagion mechanism using the structural equation model on the basis of China’s shadow banks is tested; based on the three risk infection paths, the prevention and control strategies for risk infection using the mathematical models of epidemic diseases are designed. Findings There are three network risk contagion paths between shadow banks. One, the credit network, risks are infected crossly mainly through debt and equity relationships; two, the BRN, risks are infected crossly mainly through business network and macro policy transmission; three, investor SN, risks are infected crossly mainly through individual SN and fractal relationships. The following three strategies for preventing risk’s cross-contagion between shadow banks: one, the in advance preventing strategy is more effective than the ex post control strategy; two, increasing the risk management coefficient; three, reducing the number of risk-infected submarkets. Originality/value The research of this study, especially the strategies for preventing the risks’ cross-contagion, could provide theoretical and practical guidance for regulatory authorities in formulating risk supervision measures.

Corporate social responsibility and access to bank loan: How much and how to give both matter

Purpose This paper aims to investigate the inverse U-shape relationship between DM and accessing loans from the banks and explore the moderating effect of donation mode diversity. Design/methodology/approach Based on a survey dataset of 1,036 private firms in China, we use a Heckman two-stage estimation model to test hypothesizes. Findings The results show an invert U-shape relationship between donation magnitude and access to bank loan. The authors also find that donation mode diversity will positively moderate donation magnitude–bank loan relationship: the positive effect of donation magnitude will be stronger for the private firms using multiple channels of philanthropic donation. Originality/value This paper extends the literatures by examining how philanthropic donation behaviors in form of donation magnitude (how much to give) and donation mode diversity (how to give) influence private firms’ loan borrowed from the bank, an important but largely ignored stakeholder. Therefore, it suggests that both the amount and the channels of philanthropic donation could have significant roles in the efficiency of achieving strategic outcomes of corporate philanthropy.

Analysis of patent documents with utility mining: a case study of wind energy technology

Purpose This study aims to propose a novel approach based on utility mining to find the associations among wind energy technologies. Design/methodology/approach The proposed approach uses patent documents and utility mining. Associations among wind energy technologies have been evaluated to show how the proposed approach works in practice. Findings Determining the relationships between wind energy technologies provide essential information to investors and decision-makers. Therefore, a real-life case study of wind energy technology is performed to show how the proposed approach works in practice. The proposed approach founds technology classes associated with wind energy technology. Furthermore, the strongest associations among technologies are also obtained by the proposed approach. The results of the case study show that the proposed approach can be easily used in practice. The maximum size of itemsets is 18-level itemsets. Y02E and F03D cooperative patent classification (CPC) codes appear on all itemsets. As the technologies of Y02E and F03D are directly correlated, they will be mutually developed in the future. Additionally, the number of patent corresponding to Y02E and F03D CPC codes are 7,494 and 6,577, respectively. Originality/value This is the first study that applies the utility mining-based approach to patent documents. Different levels of importance among technologies based on patent citations and the number of repetitions of each technology class are considered in the proposed approach.

Stochastic optimization for transportation planning in disaster relief under disruption and uncertainty

Purpose This study aims to minimize the expected arrival time of relief vehicles to the affected areas, considering the destruction of potential routes and disruptions due to disasters. In relief operations, required relief items in each affected area and disrupted routes are considered as uncertain parameters. Additionally, for a more realistic consideration of the situations, it is assumed that the demand of each affected area could be met by multiple vehicles and distribution centers (DCs) and vehicles have limited capacity. Design/methodology/approach The current study developed a two-stage stochastic programming model for the distribution of relief items from DCs to the affected areas. Locating the DCs was the first-stage decisions in the introduced model. The second-stage decisions consisted of routing and scheduling of the vehicles to reach the affected areas. Findings In this paper, 7th district of Tehran was selected as a case study to assess the applicability of the model, and related results and different sensitivity analyses were presented as well. By carrying out a simultaneous sensitivity analysis on the capacity of vehicles and the maximum number of DCs that can be opened, optimal values for these parameters were determined, that would help making optimal decisions upon the occurrence of a disaster to decrease total relief time and to maximize the exploitation of available facilities. Originality/value The contributions of this paper are as below: presenting an integrated model for the distribution of relief items among affected areas in the response phase of a disaster, using a two-stage stochastic programming approach to cope with route disruptions and uncertain demands for relief items, determining location of the DCs and routing and scheduling of vehicles to relief operations and considering a heterogeneous fleet of capacitated relief vehicles and DCs with limited capacity and fulfilling the demand of each affected area by more than one vehicle to represent more realistic situations.

Artificial intelligence and social responsibility: the case of the artificial intelligence strategies in the United States, Russia, and China

Purpose The purpose of this paper is to review and analyze how the development and utilization of artificial intelligence (AI) technologies for social responsibility are defined in the national AI strategies of the USA, Russia and China. Design/methodology/approach The notion of responsibility concerning AI is currently not legally defined by any country in the world. The authors of this research are going to use the methodology, based on Luciano Floridi’s Unified framework of five principles for AI in society, to determine how social responsibility is implemented in the AI strategies of the USA, Russia and China. Findings All three strategies for the development of AI in the USA, Russia and China, as evaluated in the paper, contain some or other components aimed at achieving public responsibility and responsible use of AI. The Unified framework of five principles for AI in society, developed by L. Floridi, can be used as a viable assessment tool to determine at least in general terms how social responsibility is implied and implemented in national strategic documents in the field of AI. However, authors of the paper call for further development in the field of mutually recognizable ethical models for socially beneficial AI. Practical implications This study allows us to better understand the linkages, overlaps and differences between modern philosophy of information, AI-ethics, social responsibility and government regulation. The analysis provided in this paper can serve as a basic blueprint for future attempts to define how social responsibility is understood and implied by government decision-makers. Originality/value The analysis provided in the paper, however general and empirical it may be, is a first-time example of how the Unified framework of five principles for AI in society can be applied as an assessment tool to determine social responsibility in AI-related official documents.