From Identification to Signatures via the Fiat-Shamir Transform: Minimizing Assumptions for Security and Forward-Security

The Fiat-Shamir paradigm for transforming identification schemes into signature schemes has been popular since its introduction because it yields efficient signature schemes, and has been receiving renewed interest of late as the main tool in deriving forward-secure signature schemes. We find minimal (meaning necessary and sufficient) conditions on the identification scheme to ensure security of the signature scheme in the random oracle model, in both the usual and the forward-secure cases. Specifically we show that the signature scheme is secure (resp. forward-secure) against chosen-message attacks in the random oracle model if and only if the underlying identification scheme is secure (resp. forward-secure) against impersonation under passive (i.e.. eavesdropping only) attacks, and has its commitments drawn at random from a large space. An extension is proven incorporating a random seed into the Fiat-Shamir transform so that the commitment space assumption may be removed

Study of an Optimized Micro-Grid’s Operation with Electrical Vehicle-Based Hybridized Sustainable Algorithm

Recently, the expansion of energy communities has been aided by the lowering cost of storage technologies and the appearance of mechanisms for exchanging energy that is driven by economics. An amalgamation of different renewable energy sources, including solar, wind, geothermal, tidal, etc., is necessary to offer sustainable energy for smart cities. Furthermore, considering the induction of large-scale electric vehicles connected to the regional micro-grid, and causes of increase in the randomness and uncertainty of the load in a certain area, a solution that meets the community demands for electricity, heating, cooling, and transportation while using renewable energy is needed. This paper aims to define the impact of large-scale electric vehicles on the operation and management of the microgrid using a hybridized algorithm. First, with the use of the natural attributes of electric vehicles such as flexible loads, a large-scale electric vehicle response dispatch model is constructed. Second, three factors of micro-grid operation, management, and environmental pollution control costs with load fluctuation variance are discussed. Third, a hybrid gravitational search algorithm and random forest regression (GSA-RFR) approach is proposed to confirm the method’s authenticity and reliability. The constructed large-scale electric vehicle response dispatch model significantly improves the load smoothness of the micro-grid after the large-scale electric vehicles are connected and reduces the impact of the entire grid. The proposed hybridized optimization method was solved within 296.7 s, the time taken for electric vehicle users to charge from and discharge to the regional micro-grid, which improves the economy of the micro-grid, and realizes the effective management of the regional load. The weight coefficients λ1 and λ2 were found at 0.589 and 0.421, respectively. This study provides key findings and suggestions that can be useful to scholars and decisionmakers

The in vitro cytotoxicity against human melanoma cells, tyrosinase inhibition and antioxidant activity of Grewia tenax leaves extracts

Grewia tenax (Forssk.) Fiori (Malvaceae) grows in the Arabian Peninsula and is used for several medicinal purposes. To characterize the dermatological bioactivities of G. tenax in terms of its antimelanoma, antityrosinase and antioxidant activities. Cytotoxicity was assessed by cell proliferation and mitochondrial viability assays. Ability to inhibit mushroom tyrosinase and scavenge free radicals were evaluated by an enzymatic and DPPH scavenging microtiter assay, respectively. Phytochemical analyses were carried out using TLC, HPLC-UV and NMR. The chloroform extract shown significant cytotoxic activity in terms of mitochondrial viability (43 ± 14 µg/mL). We identified lupeol and b-sitosterol as the main active components for the tyrosinase inhibitory activity of the hexane extract. Scavenging activity of the DPPH· radical was confined to the water extract. Extracts from this plant have the potential to be used as a base in the development of cosmeceutical products intended to whiten skin or to combat radical-induced physiopathological processes

What makes courier service creative?—From managing logistics to managing knowledge

The recent online business blossom has stimulated the soaring demand for logistics service, or rather, courier service, which emerged as a robust momentum of economic growth worldwide. So, to satisfy the fast-changing online businesses, courier services have been urged to be more creative to ensure the desired efficient movement of goods and services along the supply chain, especially in logistics and parcel deliveries. How could the courier service be more creative? What makes courier service creative has not yet been fully explored. Therefore, this study aimed to unveil the antecedents of creativity of courier services from the perspective of managing knowledge which is regarded as the source of wisdom. Taking into consideration the logistical nature of courier service, the proposed framework integrates logistics into knowledge management, and focuses on empirically detecting its relationship with creativity in the context of Malaysia. The results prove that the logistics-related knowledge management (LRKM) affects creativity in a significant and positive manner. However, amongst the four select constructs, only the logistics-related knowledge dissemination (LRKD) followed by the logistics-related knowledge responsiveness (LRKR) are significant operational contributors in the development of creativity in courier services. The logistics-related knowledge generation (LRKG) and logistics-related shared interpretation (LRKS) have not yet appeared significant, which is mainly due to the current insufficient development of the courier service in Malaysia. It indicates that to further enhance creativity, courier service providers should attach importance on managing knowledge of logistics operation, especially in the respects of dissemination and responsiveness, while more efforts shall be exerted to the generation and shared interpretation as both are still having positive potentials towards creativity. This study is amongst the pioneers to cross-extend the theory of logistics management and knowledge management into the courier service industry, and it also expands the application of the theory of creativity into the courier service industry. Future study could further examine the inter-relationships among the detected constructs, the effects of creativity of courier service on the performance of e-business firms, and so on

A new synthesis route for sustainable gold copper utilization in direct formic acid fuel cells

In the efforts to develop a more sustainable energy mix there is an urgent need to develop new materials for environmentally friendly processes. Developing low metal loading anode catalyst with high electrocatalytic activity for liquid fuel cells remains a great challenge. Polyvinylpyrrolodoneprotected AuCu-C core-shell was fabricated by a facile one-pot modified chemical reduction method. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM) analyses. XRD analysis indicates the preferential orientation of catalytically active (111) planes in AuCu-C core-shell nanoparticles. The inclusion of Cu in the AuCuC catalysts increased catalytic activities, which can be attributed to the increases lattice parameters. Comparative results show that AuCu-C catalyst exhibited much better electrocatalytic activity and stabilization compared to commercial Au nanoparticle on carbon support catalyst. The high performance of AuCu-C catalyst may be attributed to the electronic coupling or synergistic interaction between Cu core structure, and the Au shell makes it a promising for DFAFCs application

Trustworthy Cloud Computing

Trustworthy cloud computing has been a central tenet of the European Union cloud strategy for nearly a decade. This chapter discusses the origins of trustworthy computing and specifically how the goals of trustworthy computing—security and privacy, reliability, and business integrity—are represented in computer science research. We call for further inter- and multi-disciplinary research on trustworthy cloud computing that reflect a more holistic view of trust

The Initial-Final Mass Relation among White Dwarfs in Wide Binaries

We present the initial-final mass relation derived from 10 white dwarfs in wide binaries that consist of a main sequence star and a white dwarf. The temperature and gravity of each white dwarf was measured by fitting theoretical model atmospheres to the observed spectrum using a $\chi^{2}$ fitting algorithm. The cooling time and mass was obtained using theoretical cooling tracks. The total age of each binary was estimated from the chromospheric activity of its main sequence component to an uncertainty of about 0.17 dex in log \textit{t} The difference between the total age and white dwarf cooling time is taken as the main sequence lifetime of each white dwarf. The initial mass of each white dwarf was then determined using stellar evolution tracks with a corresponding metallicity derived from spectra of their main sequence companions, thus yielding the initial-final mass relation. Most of the initial masses of the white dwarf components are between 1 - 2 M$_{\odot}$. Our results suggest a correlation between the metallicity of a white dwarf's progenitor and the amount of post-main-sequence mass loss it experiences - at least among progenitors with masses in the range of 1 - 2 M$_{\odot}$. A comparison of our observations to theoretical models suggests that low mass stars preferentially lose mass on the red giant branch.Comment: 28 pages, 8 figures, accepted for publication in Ap

Universal Plant DNA Barcode Loci May Not Work in Complex Groups: A Case Study with Indian Berberis Species

BACKGROUND: The concept of DNA barcoding for species identification has gained considerable momentum in animals because of fairly successful species identification using cytochrome oxidase I (COI). In plants, matK and rbcL have been proposed as standard barcodes. However, barcoding in complex genera is a challenging task. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the species discriminatory power of four reportedly most promising plant DNA barcoding loci (one from nuclear genome--ITS, and three from plastid genome--trnH-psbA, rbcL and matK) in species of Indian Berberis L. (Berberidaceae) and two other genera, Ficus L. (Moraceae) and Gossypium L. (Malvaceae). Berberis species were delineated using morphological characters. These characters resulted in a well resolved species tree. Applying both nucleotide distance and nucleotide character-based approaches, we found that none of the loci, either singly or in combinations, could discriminate the species of Berberis. ITS resolved all the tested species of Ficus and Gossypium and trnH-psbA resolved 82% of the tested species in Ficus. The highly regarded matK and rbcL could not resolve all the species. Finally, we employed amplified fragment length polymorphism test in species of Berberis to determine their relationships. Using ten primer pair combinations in AFLP, the data demonstrated incomplete species resolution. Further, AFLP analysis showed that there was a tendency of the Berberis accessions to cluster according to their geographic origin rather than species affiliation. CONCLUSIONS/SIGNIFICANCE: We reconfirm the earlier reports that the concept of universal barcode in plants may not work in a number of genera. Our results also suggest that the matK and rbcL, recommended as universal barcode loci for plants, may not work in all the genera of land plants. Morphological, geographical and molecular data analyses of Indian species of Berberis suggest probable reticulate evolution and thus barcode markers may not work in this case