Towards Developing Privacy-Preserved Data Security Approach(PP-DSA)in Cloud Computing Environment

In the present scenario of rapid growth in cloud computing models,several companies and users started to share their data on cloud servers.However,when the model is not completely trusted,the data owners face several security-related problems,such as user privacy breaches,data disclosure,data corruption,and so on,during the process of data outsourcing.For addressing and handling the security-related issues on Cloud,several models were proposed.With that concern,this paper develops a Privacy-Preserved Data Security Approach(PP-DSA)to provide the data security and data integrity for the out-sourcing data in Cloud Environment.Privacy preservation is ensured in this work with the Efficient Authentication Technique(EAT)using the Group Signature method that is applied with Third-Party Auditor(TPA).The role of the auditor is to secure the data and guarantee shared data integrity.Additionally,the Cloud Service Provider(CSP)and Data User(DU)can also be the attackers that are to be handled with the EAT.Here,the major objective of the work is to enhance cloud security and thereby,increase Quality of Service(QoS).The results are evaluated based on the model effectiveness,security,and reliability and show that the proposed model provides better results than existing works.

Overview of SSRF phase-Ⅱ beamlines

The SSRF phase-Ⅱ beamline project was launched in 2016. Its major goal was to establish a systematic state-of-the-art experimental facility for third-generation synchrotron radiation to solve problems in cutting-edge science and technology.Currently, the construction is fully completed. All 16 newly built beamlines with nearly 60 experimental methods passed acceptance testing by the Chinese Academy of Sciences and are in operation.

3-Multi ranked encryption with enhanced security in cloud computing

Searchable Encryption(SE)enables data owners to search remotely stored ciphertexts selectively.A practical model that is closest to real life should be able to handle search queries with multiple keywords and multiple data owners/users,and even return the top-k most relevant search results when requested.We refer to a model that satisfies all of the conditions a 3-multi ranked search model.However,SE schemes that have been proposed to date use fully trusted trapdoor generation centers,and several methods assume a secure connection between the data users and a trapdoor generation center.That is,they assume the trapdoor generation center is the only entity that can learn the information regarding queried keywords,but it will never attempt to use it in any other manner than that requested,which is impractical in real life.In this study,to enhance the security,we propose a new 3-multi ranked SE scheme that satisfies all conditions without these security assumptions.The proposed scheme uses randomized keywords to protect the interested keywords of users from both outside adversaries and the honest-but-curious trapdoor generation center,thereby preventing attackers from determining whether two different queries include the same keyword.Moreover,we develop a method for managing multiple encrypted keywords from every data owner,each encrypted with a different key.Our evaluation demonstrates that,despite the trade-off overhead that results from the weaker security assumption,the proposed scheme achieves reasonable performance compared to extant schemes,which implies that our scheme is practical and closest to real life.

Advanced User-Based Interaction Model in Cloud

With the increasing popularity of cloud computing, there is an increased de mand for cloud resources in cloud. It has be come even more urgent to find solutions to improve resource utilization. From the per spective of a cloud consumer, a cloud applica tion processes a large information flow in volving user actions that access resources, but little work has so far been devoted to research from the perspective of the interaction be tween the user and the cloud application. In this paper, we analyze the interaction in detail, and propose a general mathematical interac tion model to formulate the challenge pertain ing to storage resource allocation as an opti mization problem, focusing on minimizing both the user＇s cost and server＇s consumption. A potential response mechanism is then de signed based on the interaction model. Fur thermore, the proposed model is used to ex plore strategies when multiple users access the same file simultaneously. Additionally, an improved queuing system, namely M/ G~ oo queue with standby, is introduced. Finally, an evaluation is presented to verify the interac- tion model.

Enhanced Trust Based Access Control for Multi-Cloud Environment

Security is an essential part of the cloud environment.For ensuring the security of the data being communicated to and from the cloud server,a significant parameter called trust was introduced.Trust-based security played a vital role in ensuring that the communication between cloud users and service providers remained unadulterated and authentic.In most cloud-based data distribution environments,emphasis is placed on accepting trusted client users’requests,but the cloud servers’integrity is seldom verified.This paper designs a trust-based access control model based on user and server characteristics in a multi-cloud environment to address this issue.The proposed methodology consists of data encryption using Cyclic Shift Transposition Algorithm and trust-based access control method.In this trust-based access control mechanism framework,trust values are assigned to cloud users using direct trust degrees.The direct trust degree is estimated based on the following metrics:success and failure rate of interactions,service satisfaction index,and dishonesty level.In addition to this,trust values are assigned to cloud servers based on the metrics:server load,service rejection rate,and service access delay.The role-Based Access control policy of each user is modified based on his trust level.If the server fails to meet the minimum trust level,then another suitable server will be selected.The proposed system is found to outperform other existing systems in a multi-cloud environment.

基于航迹数据的油耗分析与研究

随着航空运输业的快速发展,传统的基于飞行程序的燃油预测无法再精确计算飞机携带的燃油量,因此如何精确地进行燃油预测成为各大航空公司稳健发展的重要目标。为了更科学地解决燃油决策量问题,首先对航迹数据进行处理,以便在计算燃油消耗(简称油耗)中使用,然后依据飞机数据基础用户手册(BADA,user manual for the based of aircraft data)数据库的油耗计算方法,在假定各航段燃油消耗率恒定的情况下建立了飞机下降进近阶段的油耗模型,并通过对所得油耗数据进行分析,提出某一飞行阶段航空公司的燃油携带建议值,最后依据中国民用航空西南地区空中交通管理局云南分局提供的雷达航迹数据进行仿真验证,验证了所设计的油耗模型较之前的传统方法更准确可行。

Mining hourly population dynamics by activity type based on decomposition of sequential snapshot data

The dynamic population distributions by activity type(e.g.working,shopping or in-home)are vital for resource allocation,urban planning and epidemic containment.Although studies have incorporated individual-level human mobility data to map population distribution by activity type,access to such data is hindered due to privacy issues and they rely on auxiliary data to provide priori activity knowledge.This paper presents a method for generating the population dynamics by activity type.We first introduce more readily available sequential snapshot data to construct the population mixture model,then decompose the population mixture,and finally estimate the dynamic population size for each activity.We test the method in the central districts of Guangzhou city,China,based on real-time Tencent user density data.Correlation analysis and accuracy assessment prove that our method can accurately estimate hourly distributions for populations engaging in working,stay-at-home,and socializing activities.The temporal distribution of the working population reproduces the regular work scenarios and socializing population displays complex spatial patterns.We also find that there is an underlying relationship between a region’s function and its dynamic population structure.The presented method has great potential for application and could provide new insight for studying urban dynamic functions.

Novel virtual user scheme to increase data confidentiality against eavesdropping in OCDMA network

We propose a novel technique to increase the confidentiality of an optical code division multiple access （OCDMA） system. A virtual user technique is analyzed and implemented to make an OCDMA system secure. Using this technique, an eavesdropper will never find an isolated authorized user＇s signal. When authorized users and virtual users transmit data synchronously and asynehronously, network security increases by 25% and 37.5%, respectively.

Why Do Applications Request My Contacts Data？ A Large-Scale Study on Openness and Control of User Contacts Permission in Android Mobile Applicaitons Marketplace

To understand the value of data transfer, this paper uses consumers＇ contact information in mobile application that resides in their mobile devices as a proxy to evaluate the value of user data to application developer and platform owner. Based on a data set of 567,730 Android mobile applications, our research results show that using user contacts can increase application popularity, enable developer to become more influential, and have a positive effect on developers＇ productivity when developing future applications. In addition to examining the use and access of a consumers extending contact information on their device, we broaden our research to examine the context and appropriateness of using this information in the context of privacy, and to a less extent education. We conclude our research with a summary of guidance to developers, consumerss, and platform owners in order to maintain a healthy application ecosystem.

Video and User′s Data Multiplexing in Desktop Video Conferencing Systems

In desktop video conferencing systems, the quality of video as well as the response speed of user′s data is important element of systematic performance. In this paper, four video and data multiplexing strategies in terminals: the Alternate Method, the Video Priority Method, the Data Priority Method, and the Dynamic Priority Method, are investigated. Their influences on transmission performances of data and video are discussed.

Networked Control System Simulation Design and Its Application

This paper presents a framework for networked control system simulation （NCSS） to enable the analysis of the influence of network transmissions on the performance of control systems. The simulation is composed of the network environment simulated using the network simulator, the control system component simulation using Matlab or C/C＋＋, and an external application programming interface. To implement the plant （sensor）, controller, and actuator nodes, an agent-based design is introduced, and a multi-agent networked control system is constructed. Therefore, the network simulator 2-26 （NS-2.26） release is extended by modifying the user data protocol （UDP） common header in order to support application data transmission between network nodes. Then, modifying the network topology parameters, networked control system simulations are analyzed for different parameter changes, such as the network bandwidth, the number of plant nodes, and the sampling period. An analysis of the influence of these parameters on network-induced delays and packet drop is made. The results show that the simulation system is an effective tool for the study of networked control systems.