Homoepitaxial regrowth habits of ZnO nanowire arrays

Synthetic regrowth of ZnO nanowires [NWs] under a similar chemical vapor transport and condensation [CVTC] process can produce abundant ZnO nanostructures which are not possible by a single CVTC step. In this work, we report three different regrowth modes of ZnO NWs: axial growth, radial growth, and both directions. The different growth modes seem to be determined by the properties of initial ZnO NW templates. By varying the growth parameters in the first-step CVTC process, ZnO nanostructures (e.g., nanoantenna) with drastically different morphologies can be obtained with distinct photoluminescence properties. The results have implications in guiding the rational synthesis of various ZnO NW heterostructures

A Game-Theoretic Approach for CSR Emergency Medical Supply Chain during COVID-19 Crisis

The COVID-19 pandemic has caused high fluctuations in the demand for medical supplies. Therefore, emergency medical supplies enterprises have faced challenges in decision making and need to consider more corporate social responsibility (CSR) in production. At the same time, the government needs to take considerable measures to support emergency medical supplies enterprises. As such, our paper researches the decision and coordination problems for emergency medical supply chain considering CSR with the government, manufacturer, and retailer. The manufacturer produces emergency medical supplies. It has additional production technological innovation efforts to improve supply efficiency and assume CSR. The retailer faces uncertain demands and is responsible for undertaking CSR to meet the demands. The government must implement a certain degree of subsidies to ease the impact of the pandemic on emergency medical supply chain enterprises. Meanwhile, our paper further explores the obligations of the economy, society, and efficiency of enterprises under the COVID-19 pandemic and the decision making of enterprises for the implementation of CSR. Based on the principle of maximizing social welfare, we discuss decentralized decision making (without government and with government) and centralized decision making, respectively. On this basis, our paper not only designs a wholesale price–cost sharing joint contract coordination mechanism but also proves that a joint contract can achieve supply chain coordination under certain conditions. Through the analysis, we observe: (1) Government subsidies can improve the enthusiasm of supply chain members to undertake CSR; (2) With the improvement of the retailer’s CSR level, the profits of supply chain members and overall performance have improved to a certain degree; (3) To improve supply efficiency and assume social responsibility, the manufacturer implements technological innovation investment. However, it will impose some burden on the manufacturer. Government subsidies allow the manufacturer to balance between social responsibility and its profit

A Game-Theoretic Approach for CSR Emergency Medical Supply Chain during COVID-19 Crisis

The COVID-19 pandemic has caused high fluctuations in the demand for medical supplies. Therefore, emergency medical supplies enterprises have faced challenges in decision making and need to consider more corporate social responsibility (CSR) in production. At the same time, the government needs to take considerable measures to support emergency medical supplies enterprises. As such, our paper researches the decision and coordination problems for emergency medical supply chain considering CSR with the government, manufacturer, and retailer. The manufacturer produces emergency medical supplies. It has additional production technological innovation efforts to improve supply efficiency and assume CSR. The retailer faces uncertain demands and is responsible for undertaking CSR to meet the demands. The government must implement a certain degree of subsidies to ease the impact of the pandemic on emergency medical supply chain enterprises. Meanwhile, our paper further explores the obligations of the economy, society, and efficiency of enterprises under the COVID-19 pandemic and the decision making of enterprises for the implementation of CSR. Based on the principle of maximizing social welfare, we discuss decentralized decision making (without government and with government) and centralized decision making, respectively. On this basis, our paper not only designs a wholesale price–cost sharing joint contract coordination mechanism but also proves that a joint contract can achieve supply chain coordination under certain conditions. Through the analysis, we observe: (1) Government subsidies can improve the enthusiasm of supply chain members to undertake CSR; (2) With the improvement of the retailer’s CSR level, the profits of supply chain members and overall performance have improved to a certain degree; (3) To improve supply efficiency and assume social responsibility, the manufacturer implements technological innovation investment. However, it will impose some burden on the manufacturer. Government subsidies allow the manufacturer to balance between social responsibility and its profit

Dynamic Adjustment Mechanism and Differential Game Model Construction of Mask Emergency Supply Chain Cooperation Based on COVID-19 Outbreak

Incorporating the impact of the COVID-19 pandemic on the mask supply chain into our framework and taking mask output as a state variable, our study introduces the differential game to study the long-term dynamic cooperation of a two-echelon supply chain composed of the supplier and the manufacturer under government subsidies. The study elaborates that government subsidies can provide more effective incentives for supply chain members to cooperate in the production of masks compared with the situation of no government subsidies. A relatively low wholesale price can effectively increase the profits of supply chain members and the supply chain system. The joint contract of two-way cost-sharing contract and transfer payment contract can promote production technology investment efforts of the supply chain members, the optimum trajectory of mask production, and total profit to reach the best state as the centralized decision scenario within a certain range. Meanwhile, it is determined that the profits of supply chain members in the joint contract can be Pareto improvement compared with decentralized decision scenario. With the increase of production technology investment cost coefficients and output self-decay rate, mask outputs have shown a downward trend in the joint contract decision model. On the contrary, mask outputs would rise with growing sensitivity of mask output to production technology investment effort and increasing sensitivity of mask demand to mask output

Security Vulnerabilities of SGX and Countermeasures: A Survey

Funding Information: This work was supported in part by the National Natural Science Foundation of China under Grant 62072351 and Grant 61802293; in part by the National Postdoctoral Program for Innovative Talents under Grant BX20180238; in part by the Project funded by China Postdoctoral Science Foundation under Grant 2018M633461; in part by the Academy of Finland under Grant 308087 and Grant 335262; in part by the Shaanxi Innovation Team Project under Grant 2018TD-007; and in part by the 111 Project under Grant B16037. Authors’ addresses: S. F. Fei, W. X. Ding, and H. M. Xie, The State Key Lab of ISN, School of Cyber Engineering, Xidian University, 266 Xinglong Section of Xifeng Road, Xi’an, Shaanxi 710126, China; emails: [email protected], [email protected], [email protected]; Z. Yan (corresponding author), The State Key Lab of ISN, School of Cyber Engineering, Xidian University, Xi’an, Shaanxi, China and Department of Communications and Networking, School of Electrical Engineering, Aalto University, Konemiehentie 2, P.O.Box 15400, Espoo 02150, Finland; emails: [email protected], [email protected]. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]. © 2021 Association for Computing Machinery. 0360-0300/2021/07-ART126 $15.00 https://doi.org/10.1145/3456631 Publisher Copyright: © 2021 ACM.Trusted Execution Environments (TEEs) have been widely used in many security-critical applications. The popularity of TEEs derives from its high security and trustworthiness supported by secure hardware. Intel Software Guard Extensions (SGX) is one of the most representative TEEs that creates an isolated environment on an untrusted operating system, thus providing run-time protection for the execution of security-critical code and data. However, Intel SGX is far from the acme of perfection. It has become a target of various attacks due to its security vulnerabilities. Researchers and practitioners have paid attention to the security vulnerabilities of SGX and investigated optimization solutions in real applications. Unfortunately, existing literature lacks a thorough review of security vulnerabilities of SGX and their countermeasures. In this article, we fill this gap. Specifically, we propose two sets of criteria for estimating security risks of existing attacks and evaluating defense effects brought by attack countermeasures. Furthermore, we propose a taxonomy of SGX security vulnerabilities and shed light on corresponding attack vectors. After that, we review published attacks and existing countermeasures, as well as evaluate them by employing our proposed criteria. At last, on the strength of our survey, we propose some open challenges and future directions in the research of SGX security.Peer reviewe

An IoT-based risk warning system for smart libraries

Purpose: When integrating smart elements offered by emergent technologies, libraries are facing the challenges of technological renovation and maintaining their operation using emerging technology. Given the importance of smart library, new technologies are needed in building new libraries or renovation of existing libraries. The purpose of this paper is to propose a risk warning system for library construction or renovation in the aspect of risk management. Design/methodology/approach: The proposed Internet of Things (IoT)-based system consists of sensors that automatically monitor the status of materials, equipment and construction activities in real time. AI techniques including case-based reasoning and fuzzy sets are applied. Findings: The proposed system can easily track material flow and visualize construction processes. The experiment shows that the proposed system can effectively detect, monitor and manage risks in construction projects including library construction. Originality/value: Compared with existing risk warning systems, the proposed IoT-based system requires less data for making dynamic predictions. The proposed system can be applied to new builds and renovation of libraries

Temperature Effect on the Microstructures and Optical Properties of ZnO Nanowires

Temperature effects on the microstructures and optical properties of ZnO nanowires were investigated extensively. Furnace calibration results showed that temperatures inside the tube furnace had Gaussian distribution. Both radial and axial growth rates of ZnO nanowires in the Arrhenius plot fall on straight lines. With the increase of temperatures, ZnO nanowires exhibited larger diameters, better crystal qualities, and preferred growth along 〈0002〉 directions. Enhanced UV emission with the increase of growth temperatures was observed, while green emission was greatly reduced