Fine-Grained Access Control for Big Data Based on CP-ABE in Cloud Computing

In Cloud Computing, the application software and the databases are moved to large centralized data centers, where the management of the data and services may not be fully trustworthy. This unique paradigm brings many new security challenges, which have not been well solved. Data access control is an effective way to ensure the big data security in the cloud. In this paper,we study the problem of fine-grained data access control in cloud computing.Based on CP-ABE scheme,we propose a novel access control policy to achieve fine-grainedness and implement the operation of user revocation effectively.The analysis results indicate that our scheme ensures the data security in cloud computing and reduces the cost of the data owner significantly.

Accountable attribute-based authentication with fine-grained access control and its application to crowdsourcing

We introduce a new notion called accountable attribute-based authentication with fine-grained access control (AccABA), which achieves (i) fine-grained access control that prevents ineligible users from authenticating;(ii) anonymity such that no one can recognize the identity of a user;(iii) public accountability, i.e., as long as a user authenticates two different messages, the corresponding authentications will be easily identified and linked, and anyone can reveal the user’s identity without any help from a trusted third party. Then, we formalize the security requirements in terms of unforgeability, anonymity, linkability and traceability, and give a generic construction to fulfill these requirements. Based on AccABA, we further present the first attribute-based, fair, anonymous and publicly traceable crowdsourcing scheme on blockchain, which is designed to filter qualified workers to participate in tasks, and ensures the fairness of the competition between workers, and finally balances the tension between anonymity and accountability.

A fine-grained access control model for relational databases

Fine-grained access control (FGAC) must be supported by relational databases to satisfy the requirements of privacy preserving and Internet-based applications.Though much work on FGAC models has been conducted,there are still a number of ongoing problems.We propose a new FGAC model which supports the specification of open access control policies as well as closed access control policies in relational databases.The negative authorization is supported,which allows the security administrator to specify what data should not be accessed by certain users.Moreover,multiple policies defined to regulate user access together are also supported.The definition and combination algorithm of multiple policies are thus provided.Finally,we implement the proposed FGAC model as a component of the database management system (DBMS) and evaluate its performance.The performance results show that the proposed model is feasible.

Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment

The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants.

Fine-Grained Ship Recognition Based on Visible and Near-Infrared Multimodal Remote Sensing Images: Dataset,Methodology and Evaluation

Fine-grained recognition of ships based on remote sensing images is crucial to safeguarding maritime rights and interests and maintaining national security.Currently,with the emergence of massive high-resolution multi-modality images,the use of multi-modality images for fine-grained recognition has become a promising technology.Fine-grained recognition of multi-modality images imposes higher requirements on the dataset samples.The key to the problem is how to extract and fuse the complementary features of multi-modality images to obtain more discriminative fusion features.The attention mechanism helps the model to pinpoint the key information in the image,resulting in a significant improvement in the model’s performance.In this paper,a dataset for fine-grained recognition of ships based on visible and near-infrared multi-modality remote sensing images has been proposed first,named Dataset for Multimodal Fine-grained Recognition of Ships(DMFGRS).It includes 1,635 pairs of visible and near-infrared remote sensing images divided into 20 categories,collated from digital orthophotos model provided by commercial remote sensing satellites.DMFGRS provides two types of annotation format files,as well as segmentation mask images corresponding to the ship targets.Then,a Multimodal Information Cross-Enhancement Network(MICE-Net)fusing features of visible and near-infrared remote sensing images,has been proposed.In the network,a dual-branch feature extraction and fusion module has been designed to obtain more expressive features.The Feature Cross Enhancement Module(FCEM)achieves the fusion enhancement of the two modal features by making the channel attention and spatial attention work cross-functionally on the feature map.A benchmark is established by evaluating state-of-the-art object recognition algorithms on DMFGRS.MICE-Net conducted experiments on DMFGRS,and the precision,recall,mAP0.5 and mAP0.5:0.95 reached 87%,77.1%,83.8%and 63.9%,respectively.Extensive experiments demonstrate that the proposed MICE-Net has more excellent performance on DMFGRS.Built on lightweight network YOLO,the model has excellent generalizability,and thus has good potential for application in real-life scenarios.

Integrating Ontology-Based Approaches with Deep Learning Models for Fine-Grained Sentiment Analysis

Although sentiment analysis is pivotal to understanding user preferences,existing models face significant challenges in handling context-dependent sentiments,sarcasm,and nuanced emotions.This study addresses these challenges by integrating ontology-based methods with deep learning models,thereby enhancing sentiment analysis accuracy in complex domains such as film reviews and restaurant feedback.The framework comprises explicit topic recognition,followed by implicit topic identification to mitigate topic interference in subsequent sentiment analysis.In the context of sentiment analysis,we develop an expanded sentiment lexicon based on domainspecific corpora by leveraging techniques such as word-frequency analysis and word embedding.Furthermore,we introduce a sentiment recognition method based on both ontology-derived sentiment features and sentiment lexicons.We evaluate the performance of our system using a dataset of 10,500 restaurant reviews,focusing on sentiment classification accuracy.The incorporation of specialized lexicons and ontology structures enables the framework to discern subtle sentiment variations and context-specific expressions,thereby improving the overall sentiment-analysis performance.Experimental results demonstrate that the integration of ontology-based methods and deep learning models significantly improves sentiment analysis accuracy.

Fine-grained grid computing model for Wi-Fi indoor localization in complex environments

The fingerprinting-based approach using the wireless local area network(WLAN)is widely used for indoor localization.However,the construction of the fingerprint database is quite time-consuming.Especially when the position of the access point(AP)or wall changes,updating the fingerprint database in real-time is difficult.An appropriate indoor localization approach,which has a low implementation cost,excellent real-time performance,and high localization accuracy and fully considers complex indoor environment factors,is preferred in location-based services(LBSs)applications.In this paper,we proposed a fine-grained grid computing(FGGC)model to achieve decimeter-level localization accuracy.Reference points(RPs)are generated in the grid by the FGGC model.Then,the received signal strength(RSS)values at each RP are calculated with the attenuation factors,such as the frequency band,three-dimensional propagation distance,and walls in complex environments.As a result,the fingerprint database can be established automatically without manual measurement,and the efficiency and cost that the FGGC model takes for the fingerprint database are superior to previous methods.The proposed indoor localization approach,which estimates the position step by step from the approximate grid location to the fine-grained location,can achieve higher real-time performance and localization accuracy simultaneously.The mean error of the proposed model is 0.36 m,far lower than that of previous approaches.Thus,the proposed model is feasible to improve the efficiency and accuracy of Wi-Fi indoor localization.It also shows high-accuracy performance with a fast running speed even under a large-size grid.The results indicate that the proposed method can also be suitable for precise marketing,indoor navigation,and emergency rescue.

Organic matter enrichment model of fine-grained rocks in volcanic rift lacustrine basin:A case study of lower submember of second member of Lower Cretaceous Shahezi Formation in Lishu rift depression of Songliao Basin,NE China

Based on sedimentary characteristics of the fine-grained rocks of the lower submember of second member of the Lower Cretaceous Shahezi Formation(K_(1)sh_(2)^(L))in the Lishu rift depression,combined with methods of organic petrology,analysis of major and trace elements as well as biological marker compound,the enrichment conditions and enrichment model of organic matter in the fine-grained sedimentary rocks in volcanic rift lacustrine basin are investigated.The change of sedimentary paleoenvironment controls the vertical distribution of different lithofacies types in the K_(1)sh_(2)^(L)and divides it into the upper and lower parts.The lower part contains massive siliceous mudstone with bioclast-bearing siliceous mudstone,whereas the upper part is mostly composed of laminated siliceous shale and laminated fine-grained mixed shale.The kerogen types of organic matter in the lower and upper parts are typesⅡ_(2)–Ⅲand typesⅠ–Ⅱ_(1),respectively.The organic carbon content in the upper part is higher than that in the lower part generally.The enrichment of organic matter in volcanic rift lacustrine basin is subjected to three favorable conditions.First,continuous enhancement of rifting is the direct factor increasing the paleo-water depth,and the rise of base level leads to the expansion of deep-water mudstone/shale deposition range.Second,relatively strong underwater volcanic eruption and rifting are simultaneous,and such event can provide a lot of nutrients for the lake basin,which is conducive to the bloom of algae,resulting in higher productivity of typesⅠ–Ⅱ_(1)kerogen.Third,the relatively dry paleoclimate leads to a decrease in input of fresh water and terrestrial materials,including TypeⅢkerogen from terrestrial higher plants,resulting in a water body with higher salinity and anoxic stratification,which is more favorable for preservation of organic matter.The organic matter enrichment model of fine-grained sedimentary rocks of volcanic rift lacustrine basin is established,which is of reference significance to the understanding of the organic matter enrichment mechanism of fine-grained sedimentary rocks of Shahezi Formation in Songliao Basin and even in the northeast China.

Cross-Layer Framework for Fine-Grained Channel Access in Next Generation High-Density Wi Fi Networks

Densely deployed Wi Fi networks will play a crucial role in providing the capacity for next generation mobile internet. However, due to increasing interference, overlapped channels in Wi Fi networks and throughput efficiency degradation, densely deployed Wi Fi networks is not a guarantee to obtain higher throughput. An emergent challenge is how to effi ciently utilize scarce spectrum resources, by matching physical layer resources to traffi c demand. In this aspect, access control allocation strategies play a pivotal role but remain too coarse-grained. As a solution, this research proposes a flexible framework for fine-grained channel width adaptation and multi-channel access in Wi Fi networks. This approach, named SFCA(Subcarrier Fine-grained Channel Access), adopts DOFDM(Discontinuous Orthogonal Frequency Division Multiplexing) at the PHY layer. It allocates the frequency resource with a subcarrier granularity, which facilitates the channel width adaptation for multi-channel access and thus brings more fl exibility and higher frequency efficiency. The MAC layer uses a frequencytime domain backoff scheme, which combines the popular time-domain BEB scheme with a frequency-domain backoff to decrease access collision, resulting in higher access probability for the contending nodes. SFCA is compared with FICA(an established access scheme)showing significant outperformance. Finally we present results for next generation 802.11 ac Wi Fi networks.

Achieving Fine-Grained and Flexible Access Control on Blockchain-Based Data Sharing for the Internet of Things

The traditional centralized data sharing systems have potential risks such as single point of failures and excessive working load on the central node.As a distributed and collaborative alternative,approaches based upon blockchain have been explored recently for Internet of Things(IoTs).However,the access from a legitimate user may be denied without the pre-defined policy and data update on the blockchain could be costly to the owners.In this paper,we first address these issues by incorporating the Accountable Subgroup Multi-Signature(ASM)algorithm into the Attribute-based Access Control(ABAC)method with Policy Smart Contract,to provide a finegrained and flexible solution.Next,we propose a policy-based Chameleon Hash algorithm that allows the data to be updated in a reliable and convenient way by the authorized users.Finally,we evaluate our work by comparing its performance with the benchmarks.The results demonstrate significant improvement on the effectiveness and efficiency.

Experimental Study on the Effect of Fine-Grained Soil Content on the Freezing Strength of Aeolian Sand-Cement Interface

In cold regions,understanding the freezing strength of the interface between soil and structure is crucial for designing frost-resistant foundations.To investigate how the content of cement powder in aeolian sand affects this strength,we conducted direct shear tests under various conditions such as different fine-grained soil content,normal stress,and initial moisture content of the soil.By analyzing parameters like soil properties,and volume of ice content,and using the Mohr-Coulomb strength theory to define interface strength,we aimed to indirectly measure the cementation strength of the interface.Our findings revealed that as the particle content increased,the interface stress-strain curves became noticeably stiffer.We also observed a positive linear relationship between freezing strength and silt content,while the initial moisture content of the soil did not significantly impact the strengthening effect of fine-grained soil on freezing strength.Moreover,we discovered that as the powder content increased,the force binding the ice to the interface decreased,while the friction angle at the interface increased.However,the cohesion force at the interface remained relatively unchanged.Overall,our analysis suggests that the increase in freezing strength due to fine-grained soil content is primarily due to the heightened friction between aeolian sand and the interface.

Ensuring Security, Confidentiality and Fine-Grained Data Access Control of Cloud Data Storage Implementation Environment

With the development of cloud computing, the mutual understandability among distributed data access control has become an important issue in the security field of cloud computing. To ensure security, confidentiality and fine-grained data access control of Cloud Data Storage (CDS) environment, we proposed Multi-Agent System (MAS) architecture. This architecture consists of two agents: Cloud Service Provider Agent (CSPA) and Cloud Data Confidentiality Agent (CDConA). CSPA provides a graphical interface to the cloud user that facilitates the access to the services offered by the system. CDConA provides each cloud user by definition and enforcement expressive and flexible access structure as a logic formula over cloud data file attributes. This new access control is named as Formula-Based Cloud Data Access Control (FCDAC). Our proposed FCDAC based on MAS architecture consists of four layers: interface layer, existing access control layer, proposed FCDAC layer and CDS layer as well as four types of entities of Cloud Service Provider (CSP), cloud users, knowledge base and confidentiality policy roles. FCDAC, it’s an access policy determined by our MAS architecture, not by the CSPs. A prototype of our proposed FCDAC scheme is implemented using the Java Agent Development Framework Security (JADE-S). Our results in the practical scenario defined formally in this paper, show the Round Trip Time (RTT) for an agent to travel in our system and measured by the times required for an agent to travel around different number of cloud users before and after implementing FCDAC.

Fine-Grained Access Control Mechanism of Energy Internet

The Energy Internet has generated huge amounts of information on the production devices,transmission devices,and energy consumption devices.The leakage of data in the collection,transmission,and storage process will cause serious security problems.The existing Energy Internet security methods rely on traditional access control mechanisms and specific network boundary defense mechanisms,which has the limitations of static strategies and coarse design.We combine the advantages of role-based access control(RBAC)and attribute-based access control(ABAC),and propose a trusted Energy Internet fine-grained access control model based on devices'attribute and users'roles.We have not only achieved fine-grained Energy Internet resource allocation,but also ensured that the access control process is related to the security status of the environment in real time.Experimental results show that the access control model can safely and accurately execute access decisions in the Energy Internet scenario,and the processing performance is more stable.

Vertical Migration of Fine-Grained Sediments from Interior to Surface of Seabed Driven by Seepage Flows–‘Sub-Bottom Sediment Pump Action'

A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, which is defined as ‘sub-bottom sediment pump action' in this paper. Field experiments were performed twice on the intertidal flat of the Yellow River delta to study this process via both trapping the pumped materials and recording the pore pressures in the substrate. Experimental results are quite interesting as we did observe yellow slurry which is mainly composed of fine-grained soil particles appearing on the seabed surface; seepage gradients were also detected in the intertidal flat, under the action of tides and small wind waves. Preliminary conclusions are that ‘sediment pump' occurs when seepage force exceeds a certain threshold: firstly, it is big enough to disconnect the soil particles from the soil skeleton; secondly, the degree of seabed fluidization or bioturbation is big enough to provide preferred paths for the detached materials to migrate upwards. Then they would be firstly pumped from interior to the surface of seabed and then easily re-suspended into overlying water column. Influential factors of ‘sediment pump' are determined as hydrodynamics(wave energy), degree of consolidation, index of bioturbation(permeability) and content of fine-grained materials(sedimentary age). This new perspective of ‘sediment pump' may provide some implications for the mechanism interpretation of several unclear geological phenomena in the Yellow River delta area.

Effect of grain size on high-temperature stress relaxation behavior of fine-grained TC4 titanium alloy

In order to analyze the effect of grain size on stress relaxation(SR) mechanism,the SR tests of TC4 alloy with three kinds of grain size were performed in a temperature range of 650-750℃.A modified cubic delay function was used to establish SR model for each grain size.A simplified algorithm was proposed for calculating the deformation activation energy based on classical Arrhenius equation.The grain size distribution and variation were observed by microstructural methods.The experimental results indicate that smaller grains are earlier to reach the relaxation limit at the same temperature due to lower initial stress and faster relaxation rate.The SR limit at 650℃ reduces with decreasing grain size.While the effect of grain size on SR limit is not evident at 700 and 750℃ since the relaxation is fully completed.With the increase of grain size,the deformation activation energy is improved and SR mechanism at 700℃ changes from grain rotation and grain boundary sliding to dislocation movement and dynamic recovery.

δ-phase precipitation regularity of cold-rolled fine-grained GH4169 alloy plate and its effect on mechanical properties

Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy plate.The effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase content and morphology on the mechanical properties of the GH4169 alloy plates,are studied.The results demonstrate that coldrolling can promote the precipitation of theδphase and its transformation from theδ-Ni3Nb phase to theδ-NbNi4 phase.The comprehensive properties of the alloy are better when the heat treatment time is 1 h,with 132 MPa increase in the tensile strength and only 2.9%decrease in the elongation relative to those of the original material.The mechanical properties of the alloy are shown to change greatly with the change in theδ-phase morphology.

Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary

For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . The effects of salinity and humus on the fine-grained sediments have been analyzed through the synthetic study of the aspects of flocculation/coagulation power （ F）, diameter （D） and zeta potential （Z）. And the microcosmic configuration of the flocs has been analyzed by using a scan electron microscope and Fourier Transform Infrared Spectrometry. The results show that： （ 1 ） with the increase of salinity, F and D become greater and Z becomes smaller, and with the increase of the concentration of humus, F becomes smaller, but D and Z become greater; （2） the microcosmic configuration of the flocculation shows that humus packs on the fine sediments in the form of salt, and the flocculation model of C - P - OM （C stands for clay; P cations; OM organic materials） can successfully demonstrate the mechanism of the formation of the finegrained sediments in the high-turbid area of the Changjiang Estuary.

Effect of granulated rubber on shear strength of fine-grained sand

Review of the literature related to the mixture of shredded tire and sand shows that,despite of the increase in shear strength due to addition of tire chips,granulated rubber causes reduction in shear strength of sand.In this study,the shear behavior of mixtures of fine-grained sand and 1-5 mm granulated rubber is investigated.Sixty direct shear tests were conducted on sandegranulated rubber mixtures with various rubber contents(0%,5%,10%,20% and 30%) at different relative densities(50%,70% and 90%) and different normal stresses(34.5 kPa,54.5 kPa,74.5 kPa and 104.5 kPa).The obtained results show that the granulated rubber improves the shear strength of fine-grained sand at medium relative density and low normal stress.The degree of improvement in shear strength is a function of rubber content,relative density and normal stress.The results show that at relative density of 50%,by adding 5% granulated rubber,the internal friction angle of sand increases from 35.1° to 39.2°.However,at relative densities of 70% and 90%,addition of granulated rubber to sand decreases its internal friction angle.The results also indicate that the behavior of sand becomes more ductile with increasing granulated rubber content.Adding granulated rubber leads to greater yielding strain and less tangent stiffness of sand.The maximum dilation angle decreases with the decrease in granulated rubber content.The stress ratio of sample at critical state(ψ= 0°) decreases with increasing granulated rubber content.

A Holocene Yalu River-derived fine-grained deposit in the southeast coastal area of the Liaodong Peninsula

High-resolution seismic profiles and surface samples were studied in detail in order to determine the structures, provenance, and dynamic mechanisms of a fine-grained deposit in the southeast coastal area of the Liaodong Peninsula, China. Results indicate that there is a prominent fine-grained deposit distributed alongshore up to 14 m thick, which thins out to less than 2 m in both seaward and landward directions, forming an fl-shaped pattern of cross-section. The deposit is 180-300 km away from the Yalu River mouth and extends along the southeast coast of the Liaodong Peninsula between the northeast of Dalian Bay and southwest of the Changshan Islands, in water depths of 20-40 m. The deposit, which is mainly derived from the Yalu River, represents a Holocene Highstand System Tract sequence formed since the highest sea level around 7.0 ka. The Yalu River-derived sediments were redeposited in the area off the southeast coast of the Liaodong Peninsula after resuspension and transportation by the Liaonan Coastal Current.

Pore Characteristics of the Fine-Grained Tight Reservoirs in the Yabulai Basin, Northwestern China

This work investigated the pore structure characteristics and reservoir features of the finegrained tight reservoirs in the lower member of the Xinhe Formation(J2x1) in the Xiaohu subsag,Yabulai Basin based on core samples through various techniques. Interbedded silt/fine sandstones and mudstones are developed in the study area. Scanning electron microscopy(SEM) images were used to delineate different types of pores, including primary intergranular pores, secondary intergranular and intragranular pores, organic pores and fractures. The pore types were distinguished by pore size, pore area, location and formation process. The pore radii of the fine-grained rocks range from 1 nm to 1.55μm, mainly concentrated between 5 and 300 nm by low pressure N2adsorption and MICP analyses. The pore structure parameters of pore throat size and pore throat sorting coefficient are both positively correlated with porosity, while pore throat sorting coefficient has a negative correlation with permeability. The pore structures of the studied samples are much related to the mineral type and content and grain size, followed by TOC content. In these rocks with relatively low TOC and low maturity, the rigid minerals protect pores with pressure shadow from collapse, and dissolution-related pores contribute a lot to inorganic porosity. In contrast, these rocks with abundant TOC contain a large number of organic pores. The permeability of the fine-grained tight reservoir is mainly dominated by larger pore throats, while a large number of small pores(mostly <0.1 μm) contribute considerably to porosity. These results have deepened our understanding of the interbedded fine-grained tight reservoirs and can be applicable to fine-grained reservoirs in a similar setting.