The influence of moisture on atmospheric pressure plasma etching of PA6 films

Zhiqiang Gao,Shujing Peng,Jie Sun,Lan Yao,Yiping Qiu 한국물리학회 2010 Current Applied Physics Vol.10 No.1

The moisture in the substrate material may have a potential influence on atmospheric pressure plasma treatment. In order to investigate how the existence of moisture affects atmospheric pressure plasma treatment, polyamide 6 (PA6) films were treated by helium, helium/oxygen (O2) plasmas using atmospheric pressure plasma jet (APPJ) at different moisture regain. The film surfaces were investigated using contact-angle measurements, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to characterize the surfaces. The exposure of PA6 film surfaces to the plasmas led to the etching process on the surfaces and changes in the topography of the surfaces. It was shown that the etching rate and the surface roughness were higher for the 9.33% moisture regain (relative humidity 100%) group than that of the 1.61% moisture regain (relative humidity 10%) group with the same plasma gas and power.

Revitalization and Re-cultivation of Vegetation in Karst Region Through Animal

Zhiqiang Lai,Xian-feng Yi,Na Yao,Xiao-Yan Cai,Yongliang Liang,Shize Qin,Yuanrong Chen,Shangmin Qin,M. Pogaonik 한국초지조사료학회 2009 한국초지조사료학회 학술대회논문집 Vol.2009 No.08

From 2002 to 2007, two different systems (shrubs and grasses) were established to raise appropriate ruminants for the purpose of improving biological diversity and fragile ecological environment in the karst-areas through grazing. The objective was to find out a novel way to promote the application of ecological restoration and reconstruction, and the agricultural economy could develop in sustainable way in the karst areas in Guangxi and similar areas in Southwest China.

Optimization of OFDMA-Based Cellular Cognitive Radio Networks

Ma, Yao,Kim, Dong In,Wu, Zhiqiang IEEE 2010 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.58 No.8

<P>In this paper, we study the coexistence and optimization of a multicell cognitive radio network (CRN) which is overlaid with a multicell primary radio network (PRN). We propose a PRN-willingness-based design framework for coexistence and subchannel sharing, and a Lagrange duality based technique to optimize the weighted sum rate (WSR) of secondary users (SUs) over multiple cells. First, to avoid unacceptable SU interference to primary users (PUs), the PRN determines its interference margin based on its target performance metric and channel conditions, and broadcasts this information to the CRN. Second, each CRN cell optimizes its WSR and implements intercell iterative waterfilling (IC-IWF) to control the intercell interference. To account for the interference and transmit power limits at SUs, multilevel waterfilling (M-WF) and direct-power truncation (DPT) duality schemes are developed. Third, we develop a serial dual update technique which enables low-complexity and fast-convergence of the proposed duality schemes. Numerical results demonstrate the effects of multiple parameters, such as the number of SUs per cell, subchannel occupancy probability (SOP), and outage probability of the PUs. Our results show that the proposed duality schemes provide a large performance enhancement than the channel-greedy and access-fairness based resource allocation schemes.</P>

PRIAM: Privacy Preserving Identity and Access Management Scheme in Cloud

( Jinbo Xiong ),( Zhiqiang Yao ),( Jianfeng Ma ),( Ximeng Liu ),( Qi Li ),( Jun Ma ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.1

Each cloud service has numerous owners and tenants, so it is necessary to construct a privacy preserving identity management and access control mechanism for cloud computing. On one hand, cloud service providers (CSP) depend on tenant`s identity information to enforce appropriate access control so that cloud resources are only accessed by the authorized tenants who are willing to pay. On the other hand, tenants wish to protect their personalized service access patterns, identity privacy information and accessing newfangled cloud services by on-demand ways within the scope of their permissions. There are many identity authentication and access control schemes to address these challenges to some degree, however, there are still some limitations. In this paper, we propose a new comprehensive approach, called Privacy pReserving Identity and Access Management scheme, referred to as PRIAM, which is able to satisfy all the desirable security requirements in cloud computing. The main contributions of the proposed PRIAM scheme are threefold. First, it leverages blind signature and hash chain to protect tenant`s identity privacy and implement secure mutual authentication. Second, it employs the service-level agreements to provide flexible and on-demand access control for both tenants and cloud services. Third, it makes use of the BAN logic to formally verify the correctness of the proposed protocols. As a result, our proposed PRIAM scheme is suitable to cloud computing thanks to its simplicity, correctness, low overhead, and efficiency.

Data-driven Anomaly Detection Method for Monitoring Runtime Performance of Cloud Computing Platforms

Mingwei Lin,Zhiqiang Yao,Fei Gao,Yang Li 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.2

Cloud computing platforms are complex system, which consist of a lot of software working together. Because of software defects, cloud computing platforms may has performance anomaly during runtime. In this paper, a data-driven anomaly detection method is proposed to monitor runtime performance for cloud computing platforms. The proposed method can not only detect the performance anomaly of cloud computing platforms during runtime, but also find out which performance metric results in the anomaly. A series of experiments are conducted on a real private cloud computing platform based on OpenStack and experimental results show the proposed method is better than previous anomaly detection methods for cloud computing platforms.

An Efficient Portable Navigation Device with GPS and BDS Positioning Capabilities

Mingwei Lin,Zhiqiang Yao,Xiaobo An 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4

A portable navigation device is a portable electronic product, which has an important function in terms of positioning capability. In order to improve the positioning performance, an efficient portable navigation device is proposed in this paper. The proposed portable navigation device integrates the GPS receiver module and BDS receiver module, and then owns the GPS and BDS positioning capabilities simultaneously. In order to improve the performance of displaying the electronic maps, an efficient strategy based on the levels of detail is designed to display the electronic maps. A series of experiments are conducted and the experimental results show that the proposed portable navigation device can receive and analyze both the BDS and GPS data correctly, as well as the proposed strategy for displaying the electronic maps is better than the traditional strategy that displays all the map files at the same time.

A Data Transmission Model based on Adaptive Periodic Push Strategy for IaaS Cloud Computing Platforms

Mingwei Lin,Zhiqiang Yao 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.6

In this paper, a data transmission model is proposed to simulate the way of transmitting resource status information in IaaS cloud computing platforms. An adaptive periodic push strategy is also proposed to improve the performance of the data transmission model. The time interval in the adaptive periodic push strategy is dynamically updated by considering the change degree of resource status information. A series of experiments are conducted on a cloud computing testbed and experimental results show that the adaptive periodic push strategy performs better than previous data transmission strategies in terms of the number of data transmissions and data coherence.

Toward Anomaly Detection in IaaS Cloud Computing Platforms

Mingwei Lin,Zhiqiang Yao,Fei Gao,Yang Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.12

In order to monitor the running status of IaaS cloud computing platforms, performance metric data are collected to perform anomaly detection for IaaS cloud computing platforms and determine whether the IaaS cloud computing platforms fail to run normally. However, it is challenging to effectively detect performance anomalies from a large amount of noisy and high dimensional performance metric data. In this paper, an efficient anomaly detection scheme is proposed for IaaS cloud computing platforms. The proposed scheme first designs a global locality preserving projection algorithm to perform feature extraction on performance metric data, and then introduces a local outlier factor algorithm to detect anomalies. A series of experiments are conducted on a private cloud computing platform. Experimental results show that our proposed global locality preserving projection algorithm outperforms the principal components analysis algorithm and the locality preserving projection algorithm and our proposed anomaly detection scheme is better than the state-of-the-art schemes for IaaS cloud computing platforms.

A Virtual Machine Instance Anomaly Detection System for IaaS Cloud Computing

Mingwei Lin,Zhiqiang Yao,Fei Gao,Yang Li 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.3

Infrastructure as a Service (IaaS) is one of the three important fundamental service models provided by cloud computing. It provides users with computing resource and storage resource in terms of virtual machine instances. Because of the rapid development of cloud computing, more and more application systems have been deployed on the IaaS cloud computing platforms. Therefore, once anomalies incur in the IaaS cloud computing platforms, all the application systems cannot work normally. In order to enhance the dependability of IaaS cloud computing platform, a virtual machine instance anomaly detection system is proposed for IaaS cloud computing platform to detect virtual machine instances that exhibit abnormal behaviors. The proposed virtual machine instance system consists of four modules that are the data collection, the data transmission, the data storage, and the anomaly detection. In order to reduce the computing complexity and improve the detection precision, the anomaly detection module introduces the principal components analysis to reprocess the collected data and then adopts the Bayesian decision theory to detect the abnormal data. Experimental results show that the proposed virtual machine instance anomaly detection system is effective.

Towards efficient sharing of encrypted data in cloud-based mobile social network

( Xin Sun ),( Yiyang Yao ),( Yingjie Xia ),( Xuejiao Liu ),( Jian Chen ),( Zhiqiang Wang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.4

Mobile social network is becoming more and more popular with respect to the development and popularity of mobile devices and interpersonal sociality. As the amount of social data increases in a great deal and cloud computing techniques become developed, the architecture of mobile social network is evolved into cloud-based that mobile clients send data to the cloud and make data accessible from clients. The data in the cloud should be stored in a secure fashion to protect user privacy and restrict data sharing defined by users. Ciphertext-policy attribute-based encryption (CP-ABE) is currently considered to be a promising security solution for cloud-based mobile social network to encrypt the sensitive data. However, its ciphertext size and decryption time grow linearly with the attribute numbers in the access structure. In order to reduce the computing overhead held by the mobile devices, in this paper we propose a new Outsourcing decryption and Match-then-decrypt CP-ABE algorithm (OM-CP-ABE) which firstly outsources the computation-intensive bilinear pairing operations to a proxy, and secondly performs the decryption test on the attributes set matching access policy in ciphertexts. The experimental performance assessments show the security strength and efficiency of the proposed solution in terms of computation, communication, and storage. Also, our construction is proven to be replayable choosen-ciphertext attacks (RCCA) secure based on the decisional bilinear Diffie-Hellman (DBDH) assumption in the standard model.