Towards Provably Invisible Network Flow Fingerprints

Network traffic analysis reveals important information even when messages are encrypted. We consider active traffic analysis via flow fingerprinting by invisibly embedding information into packet timings of flows. In particular, assume Alice wishes to embed fingerprints into flows of a set of network input links, whose packet timings are modeled by Poisson processes, without being detected by a watchful adversary Willie. Bob, who receives the set of fingerprinted flows after they pass through the network modeled as a collection of independent and parallel $M/M/1$ queues, wishes to extract Alice's embedded fingerprints to infer the connection between input and output links of the network. We consider two scenarios: 1) Alice embeds fingerprints in all of the flows; 2) Alice embeds fingerprints in each flow independently with probability $p$. Assuming that the flow rates are equal, we calculate the maximum number of flows in which Alice can invisibly embed fingerprints while having those fingerprints successfully decoded by Bob. Then, we extend the construction and analysis to the case where flow rates are distinct, and discuss the extension of the network model

Measuring the performance of FCM versus PSO for fuzzy clustering problems

Clustering cellular manufacturing plays an important role in many industrial engineering problems. This paper investigates the performance of two methods of heuristic and metaheuristics fuzzy clustering. The proposed method investigates heuristic well-known FCM and particle swarm optimization (PSO) on some well-known benchmarks. We use two criteria of J(P) as well as Xie-Beni to compare the results. Three parameters of PSO method is tuned using design of experiment and then the results of PSO are compared versus FCM method in terms of two mentioned criteria. The proposed models are run for each instance 10 different times and, using ANOVA test, the means of two methods are compared. While the results of ANOVA do not indicate any meaningful difference between PSO and FCM in terms of J(P), we have found some meaningful differences between PSO and FCM in terms of Xie-Beni criterion. In other words, PSO performs better than FCM in terms of Xie-Beni

Optimum Parameter of a Viscous Damper for Seismic and Wind Vibration

Determination of optimal parameters of a passive control system device is the primary objective of this study. Expanding upon the use of control devices in wind and earthquake hazard reduction has led to development of various control systems. The advantage of non-linearity characteristics in a passive control device and the optimal control method using LQR algorithm are explained in this study. Finally, this paper introduces a simple approach to determine optimum parameters of a nonlinear viscous damper for vibration control of structures. A MATLAB program is used to produce the dynamic motion of the structure considering the stiffness matrix of the SDOF frame and the non-linear damping effect. This study concluded that the proposed system (variable damping system) has better performance in system response control than a linear damping system. Also, according to the energy dissipation graph, the total energy loss is greater in non-linear damping system than other systems

Asymptotic Loss in Privacy due to Dependency in Gaussian Traces

The rapid growth of the Internet of Things (IoT) necessitates employing privacy-preserving techniques to protect users' sensitive information. Even when user traces are anonymized, statistical matching can be employed to infer sensitive information. In our previous work, we have established the privacy requirements for the case that the user traces are instantiations of discrete random variables and the adversary knows only the structure of the dependency graph, i.e., whether each pair of users is connected. In this paper, we consider the case where data traces are instantiations of Gaussian random variables and the adversary knows not only the structure of the graph but also the pairwise correlation coefficients. We establish the requirements on anonymization to thwart such statistical matching, which demonstrate the significant degree to which knowledge of the pairwise correlation coefficients further significantly aids the adversary in breaking user anonymity.Comment: IEEE Wireless Communications and Networking Conferenc

Bond and Serviceability Characterization of Concrete Reinforced With High Strength Steel

Recent revisions to the AASHTO Construction Specifications permit the specification of ASTM A1035 reinforcing steel. A1035 reinforcing bars are low carbon, chromium steel bars characterized by a high tensile strength (100 or 120 ksi) and a stress-strain relationship having no yield plateau. Because of their high chromium content, A1035 bars are reported to have superior corrosion resistance when compared to conventional reinforcing steel grades. For this reason, designers have specified A1035 as a direct, one-to-one, replacement for conventional reinforcing steel as an alternative to stainless steel or epoxy-coated bars. The AASHTO LRFD Design Specifications, however, limit the yield strength of reinforcing steel to 75 ksi for most applications. Therefore, although A1035 steel is being specified for its corrosion resistance, its higher yield strength cannot be utilized.The objective of this research is to evaluate existing AASHTO LRFD Design Specifications to determine their applicability when using high strength ASTM A1035 reinforcing bars in reinforced concrete structures. The study encompasses material testing and characterization, detailed analytical studies, component tests, and full-scale member testing. The analytical and experimental research program investigates ultimate strength and service behavior and detailing of members designed with high-strength reinforcement. Specifically, the topics addressed are: a) experimental evaluation of hooked bar development length of high-strength reinforcement; b) experimental evaluation of the fatigue performance of members reinforced with high-strength reinforcement; and c) parametric evaluation of serviceability and crack opening in flexural members, comparing the results with available experimental results.The applicability of current Specification requirements for hooked bar development lengths was confirmed through a series of pull-out tests having development lengths that were shorter than those required by present Specifications equations. Tests resulted in bar rupture outside of the anchorage region with very little slip clearly indicating the efficacy of the hooked bar development requirements in Specifications. It is recommended that such anchorage regions be provided with cover and confining reinforcement ¨C based on current design requirements ¨C when high-strength bars are used. The presence of confining reinforcement effectively mitigates potential splitting failures and results in suitably conservative anchorage capacities. Two large-scale proof tests conducted as part of this study and a review of available published data demonstrate that presently accepted values for the fatigue or ¡®endurance¡¯ limit for reinforcing steel are applicable and likely conservative, when applied to higher strength bars. Additionally, it is shown that fatigue considerations will rarely affect the design of typical reinforced concrete members having fy ¡Ü 100 ksi.The extension of present AASHTO LRFD Bridge Design Specifications for hooked bar anchorage and fatigue to permit reinforcing bar yield strengths not exceeding 100 ksi was validated for concrete strengths up to 10 ksi.A fundamental issue in using A1035 or any other high-strength reinforcing steel is that the stress at service load is expected to be greater than when conventional steel is used. Consequently, the service-load reinforcing strains are greater, affecting deflection and crack widths. Based on the results of available flexural test, deflections and crack widths at service load levels were evaluated. Both metrics of serviceability were found to be within presently accepted limits, and were predictable using current Specifications provisions. A limitation on service-level stresses of fs ¡Ü 60 ksi is recommended