Two-party collaborative signature scheme is an important cryptographic technology for user authentication and data integrity protection when using mobile devices for financial and securities ...transactions. However, the two-party collaboration scheme has the following shortcomings: firstly, it is not flexible enough, and it requires the collaborating parties to be secure and trusted; secondly, the two-party collaboration security still needs to be improved. Once a hacker obtains the signature private key and collaborative identity of a mobile device, it can construct a legitimate two-party collaborative signature. Third, the application scenario of two-party co-signature is limited and cannot meet the application scenario of multi-device co-signature. For this reason, this paper designs a multi-party collaborative signature scheme based on SM2 digital signature algorithm in the standard "SM2 Elliptic Curve Public Key Cryptography" of GM/T003-2012. This scheme consists of multiple (more than 2) participants to jointly generate the signature group public key and valid signature in an interactive manner, while ensuring that each user cannot know the signature key other than their own during the signing process. We implement this scheme based on the GMP library. The experimental results show that this scheme is not only flexible but also more secure and trustworthy to meet the application scenario of multi-device collaborative signing. In addition, the time for multiple participants to construct signatures in this scheme is similar, and the time for signature verification is less different from that of the original SM2 signature.
The industrial Internet of Things (IIoT) supports recent developments in data management and information services, as well as services for smart factories. Nowadays, many mature IIoT cloud platforms ...are available to serve smart factories. However, due to the semicredibility nature of the IIoT cloud platforms, how to achieve secure storage, access control, information update and deletion for smart factory data, as well as the tracking and revocation of malicious users has become an urgent problem. To solve these problems, in this article, a blockchain-enhanced security access control scheme that supports traceability and revocability has been proposed in IIoT for smart factories. The blockchain first performs unified identity authentication, and stores all public keys, user attribute sets, and revocation list. The system administrator then generates system parameters and issues private keys to users. The domain administrator is responsible for formulating domain security and privacy-protection policies, and performing encryption operations. If the attributes meet the access policies and the user's ID is not in the revocation list, they can obtain the intermediate decryption parameters from the edge/cloud servers. Malicious users can be tracked and revoked during all stages if needed, which ensures the system security under the Decisional Bilinear Diffie-Hellman (DBDH) assumption and can resist multiple attacks. The evaluation has shown that the size of the public/private keys is smaller compared to other schemes, and the overhead time is less for public key generation, data encryption, and data decryption stages.
Abstract
Small-angle neutron scattering and high-pressure mercury intrusion capillary pressure testing are integrated to analyze the pore size distribution of the broad sense shale oil reservoir ...samples of the Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, China. The results show that, compared with the measurement method integrating gas adsorption and mercury intrusion, combination of small-angle neutron scattering and mercury intrusion can more accurately characterize full-scale pore size distribution. The full-scale pore size distribution curve of the rock samples in the study area includes two types: the declining type and submicron pore-dominated type. The declining type is mainly found with silty mudstone and dolomitic mudstone, and most of its pores are smaller than 80 nm. Silt-fine sandstones and dolarenite are mostly of the submicron pores-dominated type, with most pores smaller than 500 nm. They also present large specific pore volumes and average pore diameters of macropores and are the favorable lithogenous facies for development of high-quality reservoirs.
A series of experiments are carried out to investigate the combustion, emissions characteristics and fuel consumption of a diesel engine equipped with elliptical nozzle. The elliptical holes, which ...are made with an aspect ratio of 1.5, have a similar flow area as that of the references. In-cylinder pressure, exhaust emissions and fuel consumption are measured with varied fuel injection timing under a constant speed and different loads. The elliptical nozzles are characterized by shorter ignition delays, lower maximum rates of heat release and in-cylinder average temperature, and longer combustion durations. The NOx emission of the ICE with an elliptical nozzle is lower and while Soot emission higher. Under variable fuel injection timing, the NOx-Soot trade-off are affected by the nozzle shape. A substantial improvement in the fuel consumption-NOx emission trade-off is obtained for elliptic nozzles at three different loads. Employing moderate earlier injection couple with elliptical nozzle can reduce fuel consumption 2.5% while NOx and Soot emission remain unchanged at 25% load, and NOx emission reduce by 8.3% and 12.7%, and Soot emission reduce by 5.7% and 10.9%, and fuel consumption reduce by 2.4% and 1.7% at 50% and 75% load respectively.
•The combustion performances were studied by using elliptical diesel nozzle.•The elliptical nozzles are characterized by shorter ignition delay.•The NOx emission of elliptical nozzle is lower and Soot emission is higher.•The use of elliptical orifices can improvement in NOx-Soot trade-off.
The construction of integrated energy system can effectively improve energy efficiency and reduce carbon emission, which is of great significance to energy sustainable development. This paper ...proposes an integrated energy system operation optimization method based on cooperative game, which can effectively reduce the energy cost and carbon emissions of the system, and encourage different subjects to participate in the overall coordinated and optimized operation of the system. Firstly, combined with cooperative game theory, a cooperative game model of integrated energy system with cost and carbon emission as objectives is established. Secondly, a profit distribution method combining improved Shapley value and nucleolus method is proposed. Finally, an improved Non-dominated Sorting Genetic Algorithm is proposed to solve the cooperative game model, which greatly improves the solving efficiency. The example shows that the cooperative mode saves 26.86% of the cost and reduces 39.42% of the carbon emission compared with the independent operation. At the same time, the scientific and effective benefit distribution method proposed in this paper is verified from the overall, individual and alliance perspectives.
•Analyzed the energy architecture of different operation modes of integrated energy system.•Constructed a cooperative game model of integrated energy system.•Proposed a benefit distribution model based on the improved Shapley value and nucleolus method.•Study the influence of system cost and carbon emission by energy price fluctuation under different models.
Abstract
Background
Use of tigecycline in treating MDR Acinetobacter baumannii (MDRAB) remains controversial.
Objectives
To comprehensively assess the safety and efficacy of tigecycline in pneumonia ...caused by Acinetobacter baumannii.
Methods
PubMed, Embase, Web of Science and Cochrane library databases were searched up to 12 March 2019. Studies were included if they compared tigecycline-based regimens with other antibiotic regimens for treating AB pulmonary infections and we pooled the clinical outcomes, microbiological response, adverse events or mortality.
Results
One prospective study and nine retrospective studies were included in this meta-analysis. The results showed similar clinical cure rates (OR = 1.04, 95% CI = 0.60–1.81; P = 0.89) and mortality rates (OR = 1.11, 95% CI = 0.65–1.89; P = 0.71) comparing tigecycline groups with the control groups. However, a significantly lower microbiological eradication rate was found in the tigecycline groups (OR = 0.43, 95% CI = 0.27–0.66; P = 0.0001). Incidence of nephrotoxicity in tigecycline-based regimens was significantly lower than in colistin-based regimens (OR = 0.34, 95% CI = 0.16–0.74, I2 = 35%, P = 0.006). There were no randomized controlled trials (RCTs) included; incomplete safety data and regional bias caused by the majority of the studies originating in China are the main limitations of this meta-analysis.
Conclusions
Tigecycline can be used for treating MDRAB pulmonary infections owing to efficacy similar to that of other antibiotics. Moreover, tigecycline did not show a higher risk of mortality. Considering the lower microbiological eradication rate for tigecycline, which is likely to induce antimicrobial resistance, well-designed RCTs for high-dose tigecycline in treating pneumonia caused by AB are still needed.
The widespread use of antibiotics has led to the emergence of multidrug-resistant (MDR) bacteria such as multidrug-resistant
(AB). Tigecycline (TGC), as the first glycylcycline antibiotic approved by ...FDA, is a broad-spectrum antibiotic which remains highly effective to treat AB infections.
To confirm the TGC treatment dosage and effectiveness to treat AB infections in the Chinese population by performing therapeutic drug monitoring (TDM).
This study was performed from October 2018 through March 2019 at the PLA General Hospital. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated and employed to determine the plasma concentrations of TGC in patients with infectious diseases. The minimum inhibitory concentration (MIC) of TGC to clinically isolated AB was determined by broth microdilution method, agar dilution method, and disk diffusion method. Moreover, a model of population pharmacokinetics/pharmacodynamics (PPK/PD) was constructed.
A total of 186 plasma samples from 67 patients were detected by the validated HPLC-MS/MS method. The MIC values determined by the broth microdilution method were more sensitive and accurate than the other two methods. The microbial and clinical PK/PD breakpoints were reached when the maintenance dose of TGC was 100 mg.
Our study established a validated HPLC-MS/MS method to monitor the plasma concentrations of TGC. In view of the MIC range to AB isolates in our hospital and the PPK/PD modeling results, we recommend a relatively high dose of 100 mg q12h regimen to achieve the optimal clinical efficacy and antimicrobial response.
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•Structural characteristics and adsorption capacity of the particulate matter are investigated.•Methanol/biodiesel particulate matter shows adsorption capacity in relation to ...structure.•Blending ratio and working conditions have significant effects on particle structural characteristics.
Methanol and biodiesel are oxygenated alternative fuels with potential applications. Structural characteristics of the particulate matter have an important influence on the application and regeneration of DPF. The particulate matter were collected and measured under different methanol/biodiesel blending ratios (0 %, 10 %, 20 %), engine loads (50 %, 75 %, 100 %) and speeds (2700 r/min, 3600 r/min). The results showed that the particulate matter possesses adsorption capacity and corresponds to structure. The pore radius is distributed between 8 and 80 nm, classified as mesoporous and microporous. When the methanol blending ratio increased from 0 % to 20 %, the average particle size of particulate matter decreased by 14 nm, the specific surface area increased by 8.05 m2/g, the average pore radius decreased by 3.113 nm and the pore volume increased by 0.016 mL/g. As the load increased, the average particle size and the average pore radius decreased, while the specific surface area and pore volume increased. As the speed increased, the average particle size, specific surface area and pore volume of the particles increased, while the average pore radius decreased. Overall, the adsorption capacity of particulate matter tended to increase with increasing blending ratio, engine load and speed.
In typical alteration extraction methods, e.g., band math and principal component analysis (PCA), the bands or band combinations unitized to extract altered minerals are usually selected based on ...empirical models or previous rules. This results in significant differences in the alteration of mineral mapping even in the same area, thus greatly increasing the uncertainty of mineral resource prediction. In this paper, an intelligent alteration extraction approach was proposed in which an optimization algorithm, i.e., a genetic algorithm (GA), was introduced into the PCA; this approach is termed GA-PCA and is used for selecting the optimized band combinations of mineralized alterations. The proposed GA-PCA was employed to map iron oxides and hydroxyl minerals using the most commonly adopted multispectral data, i.e., Landsat-8 OLI data, at the Lalingzaohuo polymetallic deposits, China. The results showed that the spectral characteristics of GA-PCA-selected OLI band combinations in the research area were beneficial for enhancing alteration information and were more capable of suppressing the interference of vegetation information. The mapping alteration zones using the GA-PCA approach had a higher agreement with known ore spots, i.e., 25% and 33.3% in ferrous-bearing and hydroxyl-bearing deposits, compared to the classical PCA. Furthermore, two predicted targets (not shown in the classical PCA results) were precisely obtained via analyzing the GA-PCA alteration maps combined with the ore-forming geological conditions of the mine and its tectonic characteristics. This indicated that the intelligent selection of mineral alteration band combinations increased the reliability of remote sensing-based mineral exploration.
The tobacco industry is an important contributor to realizing the carbon reduction goal. Less attention is paid to the carbon emissions of the tobacco industry. The tobacco production system is ...generally a carbon sink, where carbon sequestration by photosynthesis in tobacco planting and by soil are sufficient to offset the carbon emissions of the tobacco production system. This work proposed an integrated framework of life-cycle assessment (LCA) and Source-Sink Model to determine the optimal allocation of carbon sources to sinks with the objective of maximizing the profitable external benefits. From an economic perspective, internal carbon sources could be offset by the internal carbon sink of the tobacco production system. The additional internal carbon sinks can be transferred in the form of carbon trading, increasing external revenue. A case-study tobacco manufacturing plant in Sichuan, China, was chosen to demonstrate the feasibility of the proposed work. This study assesses the carbon footprint and economic benefits of a tobacco industry supply chain case (from tobacco cultivation to finished product) and analyzes the energy restructuring of different percentages of renewable energy to replace thermal power. The objective of the study is to maximise the offsetting of carbon emissions from the tobacco production system, while achieving optimal internal costs and profitable external benefits.
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