Virtual Network Embedding based on Node Connectivity Awareness and Path Integration Evaluation

( Zhiyuan Zhao ),( Xiangru Meng ),( Yuze Su ),( Zhentao Li ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.7

As a main challenge in network virtualization, virtual network embedding problem is increasingly important and heuristic algorithms are of great interest. Aiming at the problems of poor correlation in node embedding and link embedding, long distance between adjacent virtual nodes and imbalance resource consumption of network components during embedding, we herein propose a two-stage virtual network embedding algorithm NA-PVNM. In node embedding stage, resource requirement and breadth first search algorithm are introduced to sort virtual nodes, and a node fitness function is developed to find the best substrate node. In link embedding stage, a path fitness function is developed to find the best path in which available bandwidth, CPU and path length are considered. Simulation results showed that the proposed algorithm could shorten link embedding distance, increase the acceptance ratio and revenue to cost ratio compared to previously reported algorithms. We also analyzed the impact of position constraint and substrate network attribute on algorithm performance, as well as the utilization of the substrate network resources during embedding via simulation. The results showed that, under the constraint of substrate resource distribution and virtual network requests, the critical factor of improving success ratio is to reduce resource consumption during embedding.

Novel Multi-user Conjunctive Keyword Search Against Keyword Guessing Attacks Under Simple Assumptions

( Zhiyuan Zhao ),( Jianhua Wang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.7

Conjunctive keyword search encryption is an important technique for protecting sensitive personal health records that are outsourced to cloud servers. It has been extensively employed for cloud storage, which is a convenient storage option that saves bandwidth and economizes computing resources. However, the process of searching outsourced data may facilitate the leakage of sensitive personal information. Thus, an efficient data search approach with high security is critical. The multi-user search function is critical for personal health records (PHRs). To solve these problems, this paper proposes a novel multi-user conjunctive keyword search scheme (mNCKS) without a secure channel against keyword guessing attacks for personal health records, which is referred to as a secure channel-free mNCKS (SCF-mNCKS). The security of this scheme is demonstrated using the Decisional Bilinear Diffie-Hellman (DBDH) and Decision Linear (D-Linear) assumptions in the standard model. Comparisons are performed to demonstrate the security advantages of the SCF-mNCKS scheme and show that it has more functions than other schemes in the case of analogous efficiency.

Different QoS Constraint Virtual SDN Embedding under Multiple Controllers

( Zhiyuan Zhao ),( Xiangru Meng ),( Siyuan Lu ),( Yuze Su ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.9

Software-defined networking (SDN) has emerged as a promising technology for network programmability and experiments. In this work, we focus on virtual network embedding in multiple controllers SDN network. In SDN virtualization environment, virtual SDN networks (vSDNs) operate on the shared substrate network and managed by their each controller, the placement and load of controllers affect vSDN embedding process. We consider controller placement, vSDN embedding, controller adjustment as a joint problem, together considering different quality of service (QoS) requirement for users, formulate the problem into mathematical models to minimize the average time delay of control paths, the load imbalance degree of controllers and embedding cost. We propose a heuristic method which places controllers and partitions control domains according to substrate SDN network, embeds different QoS constraint vSDN requests by corresponding algorithms, and migrates switches between control domains to realize load balance of controllers. The simulation results show that the proposed method can satisfy different QoS requirement of tenants, keep load balance between controllers, and work well in the acceptance ratio and revenue to cost ratio for vSDN embedding.

Verifiable Outsourced Ciphertext-Policy Attribute-Based Encryption for Mobile Cloud Computing

( Zhiyuan Zhao ),( Jianhua Wang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.6

With the development of wireless access technologies and the popularity of mobile intelligent terminals, cloud computing is expected to expand to mobile environments. Attribute-based encryption, widely applied in cloud computing, incurs massive computational cost during the encryption and decryption phases. The computational cost grows with the complexity of the access policy. This disadvantage becomes more serious for mobile devices because they have limited resources. To address this problem, we present an efficient verifiable outsourced scheme based on the bilinear group of prime order. The scheme is called the verifiable outsourced computation ciphertext-policy attribute-based encryption scheme (VOC-CP-ABE), and it provides a way to outsource intensive computing tasks during encryption and decryption phases to CSP without revealing the private information and leaves only marginal computation to the user. At the same time, the outsourced computation can be verified by two hash functions. Then, the formal security proofs of its (selective) CPA security and verifiability are provided. Finally, we discuss the performance of the proposed scheme with comparisons to several related works.

Numerical investigation of the rotating instability uniqueness in a MWe scale supercritical carbon dioxide centrifugal compressor

Zhiyuan Liu,Peng Wang,Ben Zhao 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.11

Flow instability attracts much attention for air compressors but little for a supercritical carbon dioxide (CO2) compressor that is a critical component in the supercritical CO2 Brayton cycle. This paper presents a numerical investigation of the rotating instability in a megawatt-scale (MWe-scale) supercritical CO2 centrifugal compressor from the Institute of Engineering Thermophysics. Unsteady full annulus simulations were carried out at different operating conditions and validated by the experimental data. According to the validated method, we analyzed the blade tip leakage flow, the rotating instability, and the propagation speed of the stalled flow cell. The findings are that (1) the blockage effects of leakage flow are responsible for rotating instability, and (2) the propagation speed of rotating cells is approximately 16.67% of the rotor speed. The novelty is that the figure is lower than that in air compressors, close to that found in water pumps.

Thermal Gradient–Dependent Strain Behavior of Contacted Soil Specimens Subjected to Freeze–Thaw

Xiaodong Zhao,Zhiyuan Lv,Hanqing Sun 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

Soil specimens were initially prepared by freezing with a thermal gradient (Fnonuni) and then thawing under uniform temperature (Tuni), then the strain behaviors of which using digital processing technique (DPT)–aided unconfined compression on contacted specimens were investigated. Although the specimen treated under Fnonuni - Tuni exbihted a strength over 1.8 times higher and a specimen scale–based (S–) lateral strain over 0.3 times smaller than that treated under freeze–thaw with uniform temperatures Funi - Tuni, it exhibited a relatively greater local scale–based (L–) strain level under identical S–axial strain, and dominated the deformation process of the specimen assembly. The characteristic of L–strain relationship between top and bottom specimens under Fnonuni - Tuni and specimens under Funi - Tuni approached identical when S–axial strain exceeded a threshold corresponding to the peak strength. Further, an asymmetric L–strain gradient at two sides of the fractured surface in specimens was observed, and it was more evident in specimens treated under Fnonuni - Tuni. These test data and observations obtained have been validated by detailed comparisons with previous studies, and contribute to build a constitutive model considering nonlocal variable and thus improve the settlement prediction precision of the thawed soils.

Secure and Efficient Conjunctive Keyword Search Scheme without Secure Channel

( Jianhua Wang ),( Zhiyuan Zhao ),( Lei Sun ),( Zhiqiang Zhu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.5

Conjunctive keyword search encryption is an important technique for protecting sensitive data that is outsourced to cloud servers. However, the process of searching outsourced data may facilitate the leakage of sensitive data. Thus, an efficient data search approach with high security is critical. To solve this problem, an efficient conjunctive keyword search scheme based on ciphertext-policy attribute-based encryption is proposed for cloud storage environment. This paper proposes an efficient mechanism for removing the secure channel and resisting off-line keyword-guessing attacks. The storage overhead and the computational complexity are regardless of the number of keywords. This scheme is proved adaptively secure based on the decisional bilinear Diffie-Hellman assumption in the standard model. Finally, the results of theoretical analysis and experimental simulation show that the proposed scheme has advantages in security, storage overhead and efficiency, and it is more suitable for practical applications.

Characterization and functional analysis of Krtap11-1 during hair follicle development in Angora rabbits (Oryctolagus cuniculus)

Shuang Liang,Zhiyuan Bao,Bohao Zhao,Tong Zhou,Jiali Li,Ming Liu,Shuaishuai Hu,Naisu Yang,Yang Chen,Xinsheng Wu 한국유전학회 2020 Genes & Genomics Vol.42 No.11

Background Keratin-associated protein (KAP), the structural protein molecule of hair fibers, plays a key role in determiningthe physical properties of hair. Studies of Krtap11-1 have focused only on its localization. Functional studies of Krtap11-1in hair follicle development have so far not been reported. Objective This study aimed to provide evidence for the role of Krtap11-1 in skin and hair development. Methods Full-length cloning and analysis of Krtap11-1 were conducted to ascertain its function. Overexpression vectors andinterference sequences were constructed and transfected into RAB-9 cells. Quantitative real-time polymerase chain reaction(qRT-PCR) was used to investigate the hair follicle developmental stage of Krtap11-1, the expression of different tissues,and the effects on other hair follicle development-related genes. Results The full length of cloned Krtap11-1 was 947 bp. Krtap11-1 was confirmed to be a hydrophilic protein localizedmostly in mitochondria. The greatest mRNA expression was observed in skin. Using a follicle synchronization model, itwas found that Krtap11-1 mRNA expression levels first increased then decreased over the passage of time, principally duringhair follicle catagen and telogen. Following the overexpression of Krtap11-1, mRNA expression levels of the WNT-2,KRT17, BMP-2, and TGF-β-1 genes increased, and LEF-1 decreased (P < 0.05), the converse after the corresponding useof si-RNA interference. Conclusions Krtap11-1 exerts a promoting effect. The results provide novel insight into the relationship between hair follicledevelopment and Krtap11-1 gene expression.

Heavy metal stabilization in MSWI fly ash using an additive-assisted microwave hydrothermal method

Zhiwen Xu,Zhiyuan Liang,Huaishuang Shao,Qinxin Zhao 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

The dioxins and leachable heavy metals in municipal solid waste incineration (MSWI) fly ash made it ahazardous waste. Microwave hydrothermal with four common additives, Na2S, Na2SiO3, Na2B4O7 orH3BO3, was researched at different temperatures, L/S ratios, time and additive concentrations by singlefactor and orthogonal methods to achieve effective heavy metal stabilization and waste reuse of MSWIfly ash. The samples were investigated by XRD, BET, SEM, ICP-MS to determine the influence ofadditive-assisted microwave hydrothermal on heavy metals stabilizing. According to the results of theorthogonal study, the degree of influence of each parameter heavy metals stabilization was in the orderof additive, temperature, additive concentration, time and L/S ratio. Single-factor experiments suggestedthat the conditions of 125 C, 10 min, 3 mol/L Na2S and 2 mL/g were enough for the leaching concentrationof heavy metals meeting the specified limitation of China. The results of analyses confirmed thatmicrowave hydrothermal treatment with Na2S could enhance heavy metals stabilizing by forming zeolitesfor adsorption, precipitation and convert heavy metals to a more stable state. Microwave hydrothermalwith Na2S was a promising method to manage MSWI fly ash, which greatly decrease the reactiontime and realize wastes utilization.

Cognitive Virtual Network Embedding Algorithm Based on Weighted Relative Entropy

( Yuze Su ),( Xiangru Meng ),( Zhiyuan Zhao ),( Zhentao Li ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.4

Current Internet is designed by lots of service providers with different objects and policies which make the direct deployment of radically new architecture and protocols on Internet nearly impossible without reaching a consensus among almost all of them. Network virtualization is proposed to fend off this ossification of Internet architecture and add diversity to the future Internet. As an important part of network virtualization, virtual network embedding (VNE) problem has received more and more attention. In order to solve the problems of large embedding cost, low acceptance ratio (AR) and environmental adaptability in VNE algorithms, cognitive method is introduced to improve the adaptability to the changing environment and a cognitive virtual network embedding algorithmbased on weighted relative entropy (WRE-CVNE) is proposed in this paper. At first, the weighted relative entropy (WRE) method is proposed to select the suitable substrate nodes and paths in VNE. In WRE method, the ranking indicators and their weighting coefficients are selected to calculate the node importance and path importance. It is the basic of the WRE-CVNE. In virtual node embedding stage, the WRE method and breadth first search (BFS) algorithm are both used, and the node proximity is introduced into substrate node ranking to achieve the joint topology awareness. Finally, in virtual link embedding stage, the CPU resource balance degree, bandwidth resource balance degree and path hop counts are taken into account. The path importance is calculated based on the WRE method and the suitable substrate path is selected to reduce the resource fragmentation. Simulation results show that the proposed algorithm can significantly improve AR and the long-term average revenue to cost ratio (LTAR/CR) by adjusting the weighting coefficients in VNE stage according to the network environment. We also analyze the impact of weighting coefficient on the performance of the WRE-CVNE. In addition, the adaptability of the WRE-CVNE is researched in three different scenarios and the effectiveness and efficiency of the WRE-CVNE are demonstrated.