Sharing and Privacy in PHRs: Efficient Policy Hiding and Update Attribute-based Encryption

( Zhenhua Liu ),( Jiaqi Ji ),( Fangfang Yin ),( Baocang Wang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.1

Personal health records (PHRs) is an electronic medical system that enables patients to acquire, manage and share their health data. Nevertheless, data confidentiality and user privacy in PHRs have not been handled completely. As a fine-grained access control over health data, ciphertext-policy attribute-based encryption (CP-ABE) has an ability to guarantee data confidentiality. However, existing CP-ABE solutions for PHRs are facing some new challenges in access control, such as policy privacy disclosure and dynamic policy update. In terms of addressing these problems, we propose a privacy protection and dynamic share system (PPADS) based on CP-ABE for PHRs, which supports full policy hiding and flexible access control. In the system, attribute information of access policy is fully hidden by attribute bloom filter. Moreover, data user produces a transforming key for the PHRs Cloud to change access policy dynamically. Furthermore, relied on security analysis, PPADS is selectively secure under standard model. Finally, the performance comparisons and simulation results demonstrate that PPADS is suitable for PHRs.

Research on a New Hybrid Intelligent Fault Diagnosis Method and its Application

Zhenhua Wang,Zhentao Liu,Xueyan Lan,Jian Liu,Shaowei Wang,Yangming Wu,Yanbing Xue 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.7

In order to overcome the shortcomings of slow convergence speed and easy falling into the local minimum values of the BP neural network, an improved particle swarm optimization(PSO) algorithm is proposed to optimize the redial basic function (RBF) neural network, in order to propose a new hybrid intelligent fault diagnosis(IMPSO-RBFNN) method. In the IMPSO-RBFNN method, the adaptive dynamic adjusting strategy is used to control the inertia weight of the PSO algorithm in order to an improved particle swarm optimization(IMPSO) algorithm. Then the IMPSO algorithm is selected to optimize the parameters of RBF neural network by encoding the particle and continuous iteration of the IMPSO algorithm in order to obtain the optimal combination values of the parameters of RBF neural network. The optimal combination values are regarded as the values of these parameters of the RBFNN for constructing the final IMPSO-RBFNN method. In order to test the effectiveness of the proposed IMPSO-RBFNN method, the data from bearing data center of CWRU is selected in this paper. The experiment results show that the IMPSO algorithm can effectively optimize the weights of RBFNN, the IMPSO-RBFNN method can accurately realize high precision fault diagnosis of rolling bearing.

Deformation and failure mechanism exploration of surrounding rock in huge underground cavern

Zhenhua Tian,Jian Liu,Xiaogang Wang,Lipeng Liu,Xiaobo Lv,Xiaotong Zhang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.2

In a super-large underground with “large span and high side wall”, it is buried in mountains with uneven lithology, complicated geostress field and developed geological structure. These surrounding rocks are more susceptible to stability issues during the construction period. This paper takes the left bank of Baihetan hydropower station (span is 34m) as a case study example, wherein the deformation mechanism of surrounding rock appears prominent. Through analysis of geological, geophysical, construction and monitoring data, the deformation characteristics and factors are concluded. The failure mechanism, spatial distribution characteristics, and evolution mechanism are also discussed, where rock mechanics theory, FLAC3D numerical simulation, rock creep theory, and the theory of center point are combined. In general, huge underground cavern stability issues has arisen with respect to huge-scale and adverse geological conditions since settling these issues will have milestone significance based on the evolutionary pattern of the surrounding rock and the correlation analyses, the rational structure of the factors, and the method of nonlinear regression modeling with regard to the construction and development of hydropower engineering projects among the worldwide.

Synthesis of Novel Poly(aryl ether sulfone)s Bearing Bulky Pendants for Gas Separation Membranes

Zhuang Liu,Baijun Liu,Long Li,Yinan Zhang,Zhenhua Jiang 한국고분자학회 2013 Macromolecular Research Vol.21 No.6

A hydroxylated poly(aryl ether sulfone) (PES-OH) was synthesized by a demethylation reaction of a methoxy-functionalized PES (PES-OCH3) using the HCl/pyridine system. Derived from this hydroxylated PES precursor,bulky (2-trifluoromethyl-4-nitro) phenyl (TFN) and benzophenone (BZP) were introduced to the PES backbones as side groups via aromatic nucleophilic substitution reactions. A direct property comparison of PES-OH,PES-OCH3, PES-TFN and PES-BZP has been made, and these analogues exhibited different solubility, thermal properties and gas permeability. PES grafted with the trifluoromethyl side group (PES-TFN) demonstrated more attractive permeabilities and permselectivities for O2/N2 separation compared to the others, and it exhibited the best P(O2)/P(N2) value of 8.44.

Cloning and Functional Characterization of Putative Escherichia coli ABC Multidrug Efflux Transporter YddA

( Zhenyue Feng ),( Defu Liu ),( Ziwen Liu ),( Yimin Liang ),( Yanhong Wang ),( Qingpeng Liu ),( Zhenhua Liu ),( Zhongjing Zang ),( Yudong Cui ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7

A putative multidrug efflux gene, yddA, was cloned from the Escherichia coli K-12 strain. A drugsensitive strain of E. coli missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out in wild-type (WT) and drug-sensitive E. coliΔacrB to study the yddA function. Sensitivity to different substrates of WT E.coli, E. coliΔyddA, E. coliΔacrB and E. coliΔacrBΔyddA strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors, ortho-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests. Ortho-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism E. coli is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.

Synthesis of Sulfonated Fluorenyl-Containing Poly(ether ether ketone ketone)s and Their Blends with an Amino-Functionalized Poly(ether ether ketone) for Fuel Cell Applications

Long Li,Baijun Liu,Siyuan Liu,Zhuang Liu,Yunwu Yu,Liwei Jing,Zhenhua Jiang 한국고분자학회 2013 Macromolecular Research Vol.21 No.7

A new family of sulfonated fluorenyl-containing poly(ether ether ketone ketone)s (SFPEEKKs) were successfully synthesized through a mild postsulfonation in concentrated sulfuric acid at room temperature. Further, a series of “molecule-enhanced” blend membranes were prepared based on SFPEEKKs and an amino-functionalized poly(ether ether ketone) by the solution casting method. These blend membranes generally showed higher thermal stability, lower swelling ratio and methanol permeability and superior mechanical properties in comparison with pristine SFPEEKK membranes. The results showed that some blend membranes may be promising proton exchange membranes for fuel cell applications.

(PhIO)n Mediated Annulations of Aromatic Aldehyde N-Acylhydrazones for the Synthesis of 1,3,4-Oxadiazoles

Zhenhua Shang,Jing Ha,Xiao Tao,Longpeng Xu,Qing Liu,Pan Wang 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

Parametric analysis on diagonal bracing joints connected with self-tapping screw

Zhenhua Xu,Guoliang Bai,Biao Liu,Jiarui Li,Yifan Yang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

In this paper, a three-dimensional finite element model (FEM) was established to study the performance of sliding resistance on the diagonal bracing joints of prefabricated steel frame (PSF) connected with self-tapping screw. In addition, the load-displacement curves of the joints were well verified by the test results, and a parametric study was conducted using the validated models to investigate the effect of steel grade, thickness of the tapped plate, the margin of bolt hole, the end and the central distance of bolt hole. The results showed that with the increase of steel grade, thickness of the tapped plate and the distance of the bolt holes, the anti-slide stiffness and the ultimate bearing capacity of the joint were significantly improved. It was recommended that steel grade should be Q345, Q390 or above. It was advisable to take the thickness of the tapped plate at 0.7d0 ~ 1.0d0, take the margin of bolt hole at 1.2d0 ~ 1.6d0, the central and the end distance of bolt hole should be greater than 2.0d0 and 1.2d0, respectively. The results could provide reference for engineering design.

The Design of Linear Magnetic Negative Stiffness Element for Engineering Application using Rectangular Permanent Magnets

Zhenhua Zhou,Shuhan Chen,Xin Liu 한국자기학회 2020 Journal of Magnetics Vol.25 No.2

Negative stiffness element (NSE) has extensive uses in engineering applications, such as vibration isolation, energy harvesting, and mechanical metamaterial. However, to realize a linear negative stiffness characteristic is still a challenging task. In this paper, we present a compact magnetic negative stiffness element (MNSE) that composed of three rectangular permanent magnets and configured as repelling configuration in horizontal to realize linear negative stiffness characteristic. The effects of the MNSE configuration parameters on the negative stiffness characteristic are analyzed in detail. The results demonstrate that the magnitude of the negative stiffness characteristic can be adjusted by changing the height ratio and width ratio between the central and outer magnets. The height difference between the central and outer magnets can be used to tune the degree of nonlinearity of the negative stiffness characteristic and to get the uniformity stiffness characteristic in the equilibrium position. The procedure to realize the linear negative stiffness characteristic with the expected magnitude and displacement range is developed and confirmed. The proposed MNSE and the design procedure offer an engineering application foundation for the magnetic linear negative stiffness.

Ultrathin MEMS thermoelectric generator with Bi2Te3/(Pt, Au) multilayers and Sb2Te3 legs

Liu Yang,Mu Erzhen,Wu Zhenhua,Che Zhanxun,Sun Fangyuan,Fu Xuecheng,Wang Fengdan,Wang Xinwei,Hu Zhiyu 나노기술연구협의회 2020 Nano Convergence Vol.7 No.8

Multilayer structure is one of the research focuses of thermoelectric (TE) material in recent years. In this work, n-type 800 nm ­Bi 2 Te 3 /(Pt, Au) multilayers are designed with p-type ­Sb 2 Te 3 legs to fabricate ultrathin microelectromechanical systems (MEMS) TE devices. The power factor of the annealed ­Bi 2 Te 3 /Pt multilayer reaches 46.5 μW cm −1 K −2 at 303 K, which corresponds to more than a 350% enhancement when compared to pristine ­Bi 2 Te 3 . The annealed ­Bi 2 Te 3 /Au multilayers have a lower power factor than pristine ­Bi 2 Te 3 . The power of the device with ­Sb 2 Te 3 and ­Bi 2 Te 3 /Pt multilayers measures 20.9 nW at 463 K and the calculated maximum output power reaches 10.5 nW, which is 39.5% higher than the device based on ­Sb 2 Te 3 and ­Bi 2 Te 3 , and 96.7% higher than the ­Sb 2 Te 3 and ­Bi 2 Te 3 /Au multilayers one. This work can provide an opportunity to improve TE properties by using multilayer structures and novel ultrathin MEMS TE devices in a wide variety of applications.