Towards Attacks and Defenses of Anonymous Communication Systems

Tianbo Lu,Puxin Yao1,Lingling Zhao,Yang Li,Feng Xie,Yamei Xia 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.1

Anonymous communication system has been hot topic in the field of information security, and attack techniques against anonymous systems are endless. This paper first classifies and summarizes the study of attacks against anonymous communication system in recent years, then analyzes the trend of the research on different attack technologies; secondly, it provides a comparative analysis of defense capability the mainstream anonymous communication system to the various attacks; Finally, combining the advantages and disadvantages of different systems, the authors propose an improved node selection and router forwarding algorithms for anonymous communication systems, and design an architecture of anonymous communications software based on the algorithm.

Preparation of Intumescent Flame Retardant Poly(butylene succinate) Using Urea Intercalated Kaolinite as Synergistic Agent

Lingling Gu,Sheng Zhang,Hongfei Li,Jun Sun,WuFei Tang,Liqian Zhao,Xiaoyu Gu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.8

Urea (U) was successfully intercalated into Kaolinite (Kaol) and the product K-U was introduced intopoly(butylene succinate) (PBS)/intumescent flame retardants (IFR) by melt blending. The structure of K-U was characterizedby X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The flame retardancy, thermal degradation,and combustion behavior of PBS composites were characterized by limiting oxygen index (LOI), vertical burning test to getUL-94 rating, thermogravimetricanalysis (TGA), and cone calorimeter test (Cone). With the introduction of K-U and IFRinto PBS, the LOI obviously increased from 21.9 % for neat PBS to 40.1 % for composite containing 20 wt% IFR/5 wt% KU;PBS cannot pass any UL-94 rating but the composite passed UL-94 V-0 rating. Similarly, the peak heat release rate(PHRR) in cone test decreased from 576 kW/m2 to 292 kW/m2. SEM results showed the char of the composite became morecompact and smooth.

Seeking for the National Development of Animation Art

CUI LINGLING,ZHAO GUIJING,NI MING 한국애니메이션학회 2007 한국애니메이션학회 학술대회지 Vol.2007 No.11

Experiment on the Behavior of a Self-Anchored Suspension and Cable-Stayed Hybrid Bridge during Structural Transformation

Yu Zhao,Yongjun Zhou,Lingling Wu,Changchang Li,Zhongguo John Ma 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6

The Longgang Bridge in Shaanxi, China, is a complex continuous hybrid structure composed of two cable-stayed self-anchored suspension parts and one single-pylon cable-stayed part. A 1:20-scaled model was established due to the effect of multiple structural transformation, frequent internal force changes during the construction process, and differences between actual material parameters and theoretical calculation parameters. In this paper, the design, materials, counterweight, experimental instrumentation, and construction stages of the scaled model are introduced. Based on the experimental data, the nonlinear behavior of the self-anchored suspension and cable-stayed hybrid bridge during the structural transformation of the construction process is systematically and comprehensively studied. The evolutions of the hanger force and stayed cable force, the variation in the subcable and back-cable forces, the displacement characteristics of the suspension cable and the deflection of the stiffened girder are analyzed, and the relationships among these variables in different states of the structural system are discussed. This paper will serve as a technical reference for the construction of similar bridges in the future.

Analysis on thermal stress deformation of rotary air-preheater in a thermal power plant

Hongyue Wang,Lingling Zhao,Zhigao Xu,Hyungtaek Kim 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3

Thermal stress deformation is a disadvantage of the rotary air preheater, which results in leakages of fluids and decrease of efficiency of the thermal system. To evaluate the results of deformation during its operation, the temperature distribution of storage materials is calculated by solving a simplified model. In this developed method, the effect of dimensionless parameters on the temperature distribution of rotary air preheater was investigated and compared with the results of modified heat transfer coefficient method. By solving coordination, structural and geometrical equations, and boundary condition in thermal-elastic theory, the thermal stress distributions in rotary air preheater are obtained in an analytical method. Experimental results are obtained by employing factorial design values of rotary air preheater for the validation of the calculation data. Good agreement has been yielded by comparing the analytical data and experimental data. Therefore, some conclusions necessary to undertake an adequate adjustment of thermal stress deformation have also been formulated, and online monitoring of the clearance of radial seals is proposed.

Soybean hull functionalized by phosphoric acid for sorption of copper from aqueous solution

Renmin Gong,Lingling Liu,Min Feng,Jiajing Zhao,Xingyan Liu,Shoujun Ni 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

One kind of potentially biodegradable cationic sorbent, which bears hydroxyl groups of phosphoric acid as its functional groups, with high sorption capacity of copper was prepared by thermochemically esterifying phosphoric acid (PA) onto soybean hull. Sorption of Cu(Ⅱ) from aqueous solution onto modified soybean hull (MSH) was investigated in a batch system. The sorption experiments were performed under various conditions such as different initial pH, copper concentration, MSH dosage, and contact time. The maximum copper sorption was obtained when initial solution pH≥3.5. The isothermal data of copper sorption fitted the Langmuir model and the sorption process could be described by the pseudo-first-order kinetic model. The maximum sorption capacity (Qm) of MSH for Cu(Ⅱ) was 31.55 mg/g. For 100 mg/l of Cu(Ⅱ) solution, a sorption ratio above 91% could be achieved by 5.0 g/l of MSH. The equilibrium of Cu(Ⅱ) sorption was reached within 50 min. The foreign cation and chelator in Cu(Ⅱ) solution caused decline of Cu(Ⅱ) sorption.

MODEL STRUCTURES AND RECOLLEMENTS INDUCED BY DUALITY PAIRS

Wenjing Chen,Lingling Zhao,Yanping Rao 대한수학회 2023 대한수학회보 Vol.60 No.2

Let $(\mathcal{L}, \mathcal{A})$ be a complete duality pair. We give some equivalent characterizations of Gorenstein $(\mathcal{L}, \mathcal{A})$-projective modules and construct some model structures associated to duality pairs and Frobenius pairs. Some rings are described by Frobenius pairs. In addition, we investigate special Gorenstein $(\mathcal{L}, \mathcal{A})$-projective modules and construct some model structures and recollements associated to them.

Towards a Framework for Assuring Cyber Physical System Security

Tianbo Lu,Jinyang Zhao,Lingling Zhao,Yang Li,Xiaoyan Zhang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.3

Today, cyber physical systems (CPS) are becoming popular in power networks, healthcare devices, transportation networks, industrial process and infrastructures. As cyber physical systems are used more and more extensively and thoroughly, security of cyber physical systems has become the utmost important concern in system design, implementation and research. Many kinds of attacks arise (e.g. the Stuxnet worm), causing heavy losses and serious potential security risks. For the past few years, researchers are focusing their researches on different aspects of security of cyber physical systems. In this paper, we propose a security framework assuring the security of cyber physical systems and analyze main universities and institutes studying CPS security and their relations in three levels: CPS security objectives, CPS security approaches and security in specific CPS applications. Finally, a conclusion of this article is given.

A Security Architecture in Cyber-Physical Systems : Security Theories, Analysis, Simulation and Application Fields

Tianbo Lu,Jiaxi Lin,Lingling Zhao,Yang Li,Yong Peng 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.7

Governments, companies, universities and research institutes are pushing the research and development of cyber-physical systems (CPS). However, the development of cyber-physical systems is constrained by security factors. According to this situation, this paper put forward a CPS security model, which contains security objectives, basic theories, simulation, and CPS framework, summarizes security attacks to cyber-physical systems as a theoretical reference for the study of cyber–physical systems and to provide useful security defense. Based on the cyber-physical systems framework, the paper classifies attacks for the execution layer, transport layer and control layer. The execution layer attacks include security attacks for nodes such as sensors and actuators. Transport layer attacks include data leakage or damage and security issues during massive data integration. Control layer attacks include the loss of user privacy, incorrect access control policies and inadequate security standards. This paper gives security defenses and recommendations for all types of security attacks. Finally, this paper introduces categorizations of CPS application fields and explores their relationships.

NSDA : A Novel Node Selecting Optimal Algorithm Based on Dijkstra

Tianbo Lu,Jiao Zhang,Lingling Zhao,Yang Li,Xiaoyan Zhang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.6

This paper first represent the basic conceptions of anonymous communication, then introduce the fundamentals in Anonymous Communication. Afterwards, we went deep to the classification of anonymous network topological, therefore we could get a better understanding on P2P anonymous communication system. We also systematically analyzes the existing node-select algorithms. Furthermore, we propose and implement a new node selection algorithm based on Dijkstra algorithm, named NSDA algorithm. We give a belief description about the backgrounds and design of NSDA Algorithm. The algorithm can combine the node properties with link properties to select node, which can adjust the system performancing and anonymity. In order to evaluate the NSDA algorithm, we have done experiments in Network Simulator 3, and we also explain the reason why we choose Network Simulator 3 as the simulate tool. In the end, we analyze the characteristics of NSDA algorithm according to the results of experiments.