scholarly journals CC2: Defending Hybrid Worm on Mobile Networks with Two-Dimensional Circulation Control

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Hailu Yang ◽  
Deyun Chen ◽  
Guanglu Sun ◽  
Xiaoyu Ding ◽  
Yu Xin
Keyword(s):  
Community Structure ◽  
Social Interactions ◽  
Mobile Networks ◽  
High Speed ◽  
Mobile Internet ◽  
Communication Security ◽  
Two Dimensional ◽  
Worm Propagation ◽  
Real Trace ◽  
Social Applications

As the hybrid worm can propagate by both personal social interactions and wireless communications, it has been identified as one of the most severe threats to the mobile Internet. This problem is expected to become worse with the boom of social applications and mobile services. In this work, we study the propagation dynamics of hybrid worms and propose a systematic countermeasure. The system maintains a set of community structure which describes the high-speed infection zone of worms and contains worm propagation by distributing the worm signature to the guard nodes selected from the periphery of each community. For those nodes that are geographically close but located in different communities , we evaluate the communication security between them based on the observed infection history and limit communications between insecure ones to avoid the worm spreading across communities. We also design an efficient worm signature forwarding strategy that enables most nodes in the network to reach an immune state before being infected by the worm. Extensive real-trace driven simulations verify the feasibility and effectiveness of the proposed methods.

scholarly journals Performance Evaluation of Distributed Mobility Management Protocols: Limitations and Solutions for Future Mobile Networks

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
J. Carmona-Murillo ◽  
I. Soto ◽  
F. J. Rodríguez-Pérez ◽  
D. Cortés-Polo ◽  
J. L. González-Sánchez
Keyword(s):  
Mobile Networks ◽  
Mobility Management ◽  
High Speed ◽  
Mobile Node ◽  
Mobile Internet ◽  
Wireless Access Networks ◽  
Data Traffic ◽  
Distributed Mobility Management ◽  
Signaling Cost ◽  
Mobility Management Protocols

Mobile Internet data traffic has experienced an exponential growth over the last few years due to the rise of demanding multimedia content and the increasing number of mobile devices. Seamless mobility support at the IP level is envisioned as a key architectural requirement in order to deal with the ever-increasing demand for data and to efficiently utilize a plethora of different wireless access networks. Current efforts from both industry and academia aim to evolve the mobility management protocols towards a more distributed operation to tackle shortcomings of fully centralized approaches. However, distributed solutions face several challenges that can result in lower performance which might affect real-time and multimedia applications. In this paper, we conduct an analytical and simulated evaluation of the main centralized and proposed Distributed Mobility Management (DMM) solutions. Our results show that, in some scenarios, when users move at high speed and/or when the mobile node is running long-lasting applications, the DMM approaches incur high signaling cost and long handover latency.

Load Spectrum Compiling and Fatigue Life Estimation of the Automobile Wheel Hub

2020 ◽  
Vol 13 ◽  
Author(s):  
Xintian Liu ◽  
Yang Qu ◽  
Xiaobing Yang ◽  
Yongfeng Shen
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Two Dimensional ◽  
Load Spectrum ◽  
One Dimensional ◽  
Life Estimation ◽  
Load Spectra ◽  
Fatigue Life Estimation ◽  
Program Load Spectrum ◽  
Program Load

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

Accelerating laser processes with a smart two-dimensional polygon mirror scanner for ultra-fast beam deflection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florian Roessler ◽  
André Streek
Keyword(s):  
Energy Distribution ◽  
Real Time ◽  
Laser Processing ◽  
High Speed ◽  
Beam Deflection ◽  
Two Dimensional ◽  
Heat Accumulation ◽  
Field Programmable ◽  
Drill Holes ◽  
Average Laser

Abstract In laser processing, the possible throughput is directly scaling with the available average laser power. To avoid unwanted thermal damage due to high pulse energy or heat accumulation during MHz-repetition rates, energy distribution over the workpiece is required. Polygon mirror scanners enable high deflection speeds and thus, a proper energy distribution within a short processing time. The requirements of laser micro processing with up to 10 kW average laser powers and high scan speeds up to 1000 m/s result in a 30 mm aperture two-dimensional polygon mirror scanner with a patented low-distortion mirror configuration. In combination with a field programmable gate array-based real-time logic, position-true high-accuracy laser switching is enabled for 2D, 2.5D, or 3D laser processing capable to drill holes in multi-pass ablation or engraving. A special developed real-time shifter module within the high-speed logic allows, in combination with external axis, the material processing on the fly and hence, processing of workpieces much larger than the scan field.

scholarly journals Emergence and evolution of social networks through exploration of the Adjacent Possible space

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Enrico Ubaldi ◽  
Raffaella Burioni ◽  
Vittorio Loreto ◽  
Francesca Tria
Keyword(s):  
Social Networks ◽  
Community Structure ◽  
Social Interactions ◽  
Clustering Coefficient ◽  
Human Beings ◽  
Broad Distribution ◽  
Phone Calls ◽  
Dynamical Features ◽  
Twitter Users ◽  
American Physical

AbstractThe interactions among human beings represent the backbone of our societies. How people establish new connections and allocate their social interactions among them can reveal a lot of our social organisation. We leverage on a recent mathematical formalisation of the Adjacent Possible space to propose a microscopic model accounting for the growth and dynamics of social networks. At the individual’s level, our model correctly reproduces the rate at which people acquire new acquaintances as well as how they allocate their interactions among existing edges. On the macroscopic side, the model reproduces the key topological and dynamical features of social networks: the broad distribution of degree and activities, the average clustering coefficient and the community structure. The theory is born out in three diverse real-world social networks: the network of mentions between Twitter users, the network of co-authorship of the American Physical Society journals, and a mobile-phone-calls network.

An Efficient Match Search Approach Using Two-Dimensional Hash Function in Hardware-Based Dictionary Compression

2019 ◽  
Vol 28 (06) ◽  
pp. 1950106
Author(s):  
Qian Dong ◽  
Bing Li
Keyword(s):  
Compression Ratio ◽  
Hash Function ◽  
High Speed ◽  
Two Dimensional ◽  
Time Data ◽  
Search Result ◽  
Compression Speed ◽  
Real Time Data ◽  
Real Time Data Processing ◽  
Search Approach

The hardware-based dictionary compression is widely adopted for high speed requirement of real-time data processing. Hash function helps to manage large dictionary to improve compression ratio but is prone to collisions, so some phrases in match search result are not true matches. This paper presents a novel match search approach called dual chaining hash refining, which can improve the efficiency of match search. From the experimental results, our method showed obvious advantage in compression speed compared with other approach that utilizes single hash function described in the previous publications.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

A Two-Dimensional Surface Profile Imaging Technique Based on Heterodyne Interferometer

2005 ◽  
Vol 295-296 ◽  
pp. 477-482
Author(s):  
K.W. Wang ◽  
Z.J. Cai ◽  
Li Jiang Zeng
Keyword(s):  
High Speed ◽  
Imaging Technique ◽  
Surface Profile ◽  
Ccd Camera ◽  
Measurement Range ◽  
Interference Signal ◽  
Two Dimensional ◽  
Step Method ◽  
Heterodyne Interferometer ◽  
Dimensional Surface

A two-dimensional surface profile imaging technique based on heterodyne interferometer is proposed. A piezo translator vibrated grating is used to generate a heterodyne signal. A high speed CCD camera is used to extract the interference signal using a five step method. The uncertainty in the displacement measurement is approximately 0.035 µm within a measurement range of 1.7 µm, confirming the two dimensional heterodyne interferometer is valid for measuring the surface profile. The method is also available for low coherence heterodyne interferometer due to the optical frequency shifts caused by the vibration of grating independent on the wavelength.

Aerodynamics of a two-dimensional bluff body with the cross-section of a train

2020 ◽  
Vol 23 (12) ◽  
pp. 2679-2693 ◽  
Author(s):  
Huan Li ◽  
Xuhui He ◽  
Hanfeng Wang ◽  
Si Peng ◽  
Shuwei Zhou ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Large Amplitude ◽  
High Speed ◽  
Bluff Body ◽  
Mean Amplitude ◽  
Two Dimensional ◽  
Aerodynamic Forces ◽  
Moderate Reynolds Number ◽  
Amplitude Mode

Experiments on the aerodynamics of a two-dimensional bluff body simplified from a China high-speed train in crosswinds were carried out in a wind tunnel. Effects of wind angle of attack α varying in [−20°, 20°] were investigated at a moderate Reynolds number Re = 9.35 × 104 (based on the height of the model). Four typical behaviors of aerodynamics were identified. These behaviors are attributed to the flow structure around the upper and lower halves of the model changing from full to intermittent reattachment, and to full separation with a variation in α. An alternate transition phenomenon, characterized by an alteration between large- and small-amplitude aerodynamic fluctuations, was detected. The frequency of this alteration is about 1/10 of the predominant vortex shedding. In the intervals of the large-amplitude behavior, aerodynamic forces fluctuate periodically with a strong span-wise coherence, which are caused by the anti-symmetric vortex shedding along the stream-wise direction. On the contrary, the aerodynamic forces fluctuating at small amplitudes correspond to a weak span-wise coherence, which are ascribed to the symmetric vortex shedding from the upper and lower halves of the model. Generally, the mean amplitude of the large-amplitude mode is 3 times larger than that of the small one. Finally, the effects of Reynolds number were examined within Re = [9.35 × 104, 2.49 × 105]. Strong Reynolds number dependence was observed on the model with two rounded upper corners.

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