An Optimized Deployment Mechanism for Virtual Middleboxes in NFV- and SDN-Enabling Network

( Gang Xiong ),( Penghao Sun ),( Yuxiang Hu ),( Julong Lan ),( Kan Li ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

Network Function Virtualization (NFV) and Software Defined Networking (SDN) are recently considered as very promising drivers of the evolution of existing middlebox services, which play intrinsic and fundamental roles in today`s networks. To address the virtual service deployment issues that caused by introducing NFV or SDN to networks, this paper proposes an optimal solution by combining quantum genetic algorithm with cooperative game theory. Specifically, we first state the concrete content of the service deployment problem and describe the system framework based on the architecture of SDN. Second, for the service location placement sub-problem, an integer linear programming model is built, which aims at minimizing the network transport delay by selecting suitable service locations, and then a heuristic solution is designed based on the improved quantum genetic algorithm. Third, for the service amount placement sub-problem, we apply the rigorous cooperative game-theoretic approach to build the mathematical model, and implement a distributed algorithm corresponding to Nash bargaining solution. Finally, experimental results show that our proposed method can calculate automatically the optimized placement locations, which reduces 30% of the average traffic delay compared to that of the random placement scheme. Meanwhile, the service amount placement approach can achieve the performance that the average metric values of satisfaction degree and fairness index reach above 90%. And evaluation results demonstrate that our proposed mechanism has a comprehensive advantage for network application.

A Mechanism for Configurable Network Service Chaining and Its Implementation

( Gang Xiong ),( Yuxiang Hu ),( Julong Lan ),( Guozhen Cheng ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

Recently Service Function Chaining (SFC) is promising to innovate the network service mode in modern networks. However, a feasible implementation of SFC is still difficult due to the need to achieve functional equivalence with traditional modes without sacrificing performance or increasing network complexity. In this paper, we present a configurable network service chaining (CNSC) mechanism to provide services for network traffics in a flexible and optimal way. Firstly, we formulate the problem of network service chaining and design an effective service chain construction framework based on integrating software-defined networking (SDN) with network functions virtualization (NFV). Then, we model the service path computation problem as an integer liner optimization problem and propose an algorithm named SPCM to cooperatively combine service function instances with a network utility maximum policy. In the procedure of SPCM, we achieve the service node mapping by defining a service capacity matrix for substrate nodes, and work out the optimal link mapping policies with segment routing. Finally, the simulation results indicate that the average request acceptance ratio and resources utilization ratio can reach above 85% and 75% by our SPCM algorithm, respectively. Upon the prototype system, it is demonstrated that CNSC outperforms other approaches and can provide flexible and scalable network services.

Suboptimal Relational Tree Configuration and Robust Control Based on the Leader-follower Model for Self-organizing Systems Without GPS Support

Zhi-gang Xiong,Ya-Song Luo,Zhong Liu,Zhi-kun Liu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4

This paper surveys the formation acquisition and maintenance of multi-agent systems, while the communication graph is obtained without human designations. Given that all agents move along unpredictable paths during formation acquisition, the systems adopt the leader-follower model. For better expression of the graph construction, a relational tree is introduced to describe the follower-leader pairs. Then, a distributed method is proposed for suboptimal relational tree configuration. By utilizing particle swarm optimization (PSO), the search for follower-leader pairs is converted to permutation optimization. Based on principal component analysis (PCA), the entire group is divided into several small groups, and the optimization can be implemented in each group, thus releasing the computation burden. To acquire the formation defined by the suboptimal relational tree, a second nonlinear controller subject to the loss of GPS information is established. The controller takes the reference in the local velocity frame as inputs, and proportional and differential components are introduced to provide a soft control. In addition, adaptive parameters are designed for robust control. By tuning the parameters autonomously, self-organized systems can work well in various scenarios even without manual adjustment of parameters. Mathematical and numerical analyses are conducted to prove the feasibility of the proposed strategy.

A Hybrid Computational Intelligence Approach for the VRP Problem

Gang PENG,Kehan ZENG,Xiong YANG 한국정보기술융합학회 2013 JoC Vol.4 No.2

PGQ, a novel hybrid computational intelligence approach, in which Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and quantum computation are integrated, is proposed to solve the Vehicle Routing Problem (VRP). In PSO, a quantum approach called QUP is proposed to update the particles. GA operators are employed to improve population quality. The simulation results indicate that the PGQ algorithm is very effective and is better than simple PSO and GA as well as PSO and GA mixed algorithm.

Occluded and Low Resolution Face Detection with Hierarchical Deformable Model

Xiong Yang,Gang Peng,Zhaoquan Cai,Kehan Zeng 한국정보기술융합학회 2013 JoC Vol.4 No.2

This paper presents a hierarchical deformable model for robust human face detection, especially with occlusions and under low resolution. By parsing, we mean inferring the parse tree (a configuration of the proposed hierarchical model) for each face instance. In modeling, a three-layer hierarchical model is built consisting of six nodes. For each node, an active basis model is trained, and their spatial relations such as relative locations and scales are modeled using Gaussian distributions. In computing, we run the learned active basis models on testing images to obtain bottom-up hypotheses, followed by explicitly testing the compatible relations among those hypotheses to do verification and construct the parse tree in a top-down manner. In experiments, we test our approach on CMU+MIT face test set with improved performance obtained.

Secure and Fine-grained Electricity Consumption Aggregation Scheme for Smart Grid

( Gang Shen ),( Yixin Su ),( Danhong Zhang ),( Huajun Zhang ),( Binyu Xiong ),( Mingwu Zhang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.4

Currently, many of schemes for smart grid data aggregation are based on a one-level gateway (GW) topology. Since the data aggregation granularity in this topology is too single, the control center (CC) is unable to obtain more fine-grained data aggregation results for better monitoring smart grid. To improve this issue, Shen et al. propose an efficient privacy-preserving cube-data aggregation scheme in which the system model consists of two-level GW. However, a risk exists in their scheme that attacker could forge the signature by using leaked signing keys. In this paper, we propose a secure and fine-grained electricity consumption aggregation scheme for smart grid, which employs the homomorphic encryption to implement privacy-preserving aggregation of users’ electricity consumption in the two-level GW smart grid. In our scheme, CC can achieve a flexible electricity regulation by obtaining data aggregation results of various granularities. In addition, our scheme uses the forward-secure signature with backward-secure detection (FSBD) technique to ensure the forward-backward secrecy of the signing keys. Security analysis and experimental results demonstrate that the proposed scheme can achieve forward-backward security of user’s electricity consumption signature. Compared with related schemes, our scheme is more secure and efficient.

Comparative Effectiveness of Risk-adapted Surveillance vs Retroperitoneal Lymph Node Dissection in Clinical Stage I Nonseminomatous Germ Cell Testicular Cancer: A Retrospective Follow-up Study of 81 Patients

Fan, Gang,Zhang, Lin,Yi, Lu,Jiang, Zhi-Qiang,Ke, Yang,Wang, Xiao-Shan,Xiong, Ying-Ying,Han, Wei-Qin,Zhou, Xiao,Liu, Chun,Yu, Xie Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Purpose: To retrospective assess the potential predictors for relapse and create an effective clinical mode for surveillance after orchidectomy in clinical stage I non-seminomatous germ cell testicular tumors (CSI-NSGCTs). Materials and Methods: We analyzed data for CSI-NSGCTs patients with non-lymphatic vascular invasion, %ECa < 50% (percentage of embryonal carcinoma < 50%), and negative or declining tumor markers to their half-life following orchidectomy (defined as low-risk patients); these patients were recruited from four Chinese centers between January 1999 and October 2013. Patients were divided into active surveillance group and retroperitoneal lymph node dissection (RPLND) group according to different therapeutic methods after radical orchidectomy was performed. The disease-free survival rates (DFSR) and overall survival rates (OSR) of the two groups were compared by Kaplan-Meier analysis. Results: A total of 121 patients with CSI-NSGCT were collected from four centers, and 81 low-risk patients, including 54 with active surveillance and 27 with RPLND, were enrolled at last. The median follow-up duration was 66.2 (range 6-164) months in the RPLND group and 65.9 (range 8-179) months in the surveillance group. OSR was 100% in active surveillance and RPLND groups, and DFSR was 89.8% and 87.0%, respectively. No significant difference was observed between these two groups ($X_2=0.108$, P=0.743). No significant difference was observed between the patients with a low percentage of embryonal carcinoma (<50%) and those without embryonal carcinoma (87.0% and 91.9%, $X_2=0.154$, P=0.645). No treatment-related complications were observed in the active surveillance group whereas minor and major complications were observed in 13.0% and 26.1% of the RPLND group, respectively. Conclusions: Active surveillance resulted in similar DFSR and OSR compared with RPLND in our trial. Patients with low-risk CSI-NSGCTs could benefit from risk-adapted surveillance after these patients were subjected to radical orchidectomy.

The Molecular Characterization of Serogroup C Neisseria meningitidis Strains Circulating in Beijing

Tie-gang Zhang,Jing-guo He,Xiong He,Li-Juan Chen,Zhu-jun Shao,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.6

The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.

Grain Refinement and Strengthening Mechanisms of In-situ Follow-up Hammering-Assisted Wire Arc Additive Manufacturing for Hydraulic Turbine Blade Repairing

Xiaochen Xiong,Xunpeng Qin,Lin Hua,Gang Wan,Shilong Wei,Mao Ni,Zeqi Hu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.6

An in-situ follow-up hammering-assisted (FH) wire arc additive manufacturing (WAAM) process is proposed for hydraulicturbine blade repairing. With different hammering intervention temperatures above the austenite recrystallization temperature(Tre-γ), the influence and mechanism of the process on the grain size of prior austenite grains and room-temperaturemartensite, as well as the texture of 0Cr13Ni5Mo deposited layers are systematically studied. The OM, SEM and EBSD areused for characterization. The repairing layer of large-sized blade is dominated with the coarse columnar grains with severalmillimeters in length, and the grain size is rated as grade 0. After the FH process, the prior austenite grains are significantlyrefined to grade 8. As the hammering temperature increases, the recrystallized austenite grains gradually grow and coarsenowing to the higher ambient temperature. FH at 950 ℃, a temperature slightly higher than the Tre-γ can achieve the austenitegrains with excellent grain refinement effect. Meanwhile, thanks to microstructure inheritance, the room-temperature martensiticis also refined from 4.69 to 2.47 μm, and the typical < 100 > fibre texture content in the deposited layer is obviouslyreduced with the texture intensity reduced from 6.68 to 2.95. Furthermore, the yield strength is increased by about 200 MPa. The main strengthening mechanisms are grain refinement strengthening and dislocation strengthening, and the contributionsto the yield strength are 96.1 MPa and 79 MPa respectively. Additionally, the FH process is also expected to simultaneouslyimprove the formability of the blade repaired layer.

Laboratory Confirmation of A Suspicious Meningococcal Meningitis Death Case

Tie-gang Zhang,Li-juan Chen,Jie Yang,Zhu-jun Shao,Xiong He,Jing-guo He,Ming Luo,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.4

A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.