Security Reputation Metrics

Security reputation metrics (aka. security metrics) quantify the security levels of organization (e.g., hosting or Internet access providers) relative to comparable entities. They enable benchmarking and are essential tools for decision and policy-making in security, and may be used to govern and steer responsible parties towards investing in security when economic or other decision-making factors may drive them to do otherwise

Herding Vulnerable Cats: A Statistical Approach to Disentangle Joint Responsibility for Web Security in Shared Hosting

Hosting providers play a key role in fighting web compromise, but their ability to prevent abuse is constrained by the security practices of their own customers. {\em Shared} hosting, offers a unique perspective since customers operate under restricted privileges and providers retain more control over configurations. We present the first empirical analysis of the distribution of web security features and software patching practices in shared hosting providers, the influence of providers on these security practices, and their impact on web compromise rates. We construct provider-level features on the global market for shared hosting -- containing 1,259 providers -- by gathering indicators from 442,684 domains. Exploratory factor analysis of 15 indicators identifies four main latent factors that capture security efforts: content security, webmaster security, web infrastructure security and web application security. We confirm, via a fixed-effect regression model, that providers exert significant influence over the latter two factors, which are both related to the software stack in their hosting environment. Finally, by means of GLM regression analysis of these factors on phishing and malware abuse, we show that the four security and software patching factors explain between 10\% and 19\% of the variance in abuse at providers, after controlling for size. For web-application security for instance, we found that when a provider moves from the bottom 10\% to the best-performing 10\%, it would experience 4 times fewer phishing incidents. We show that providers have influence over patch levels--even higher in the stack, where CMSes can run as client-side software--and that this influence is tied to a substantial reduction in abuse levels

Measurement of loss in superconducting microstrip at millimeter-wave frequencies

We have developed a new technique for accurate measurement of the loss of superconducting microstrips at mm-wave frequencies. In this technique, we optically couple power to slot antenna, which is connected to one port of a hybrid coupler. One of the output ports of the hybrid delivers power to a series of mm-wave microstrip resonators which are capacitively coupled to a feedline followed by an MKID (microwave kinetic inductance detector) that measures the transmitted power. Two other MKIDs are connected to the remaining ports of the hybrid to measure the total incident optical power and the power reflected from the mm-wave resonators, allowing |S_(21)|^2 and |S_(11)|^2 to be accurately determined and resonance frequency fr and quality factor Q to be retrieved. We have fabricated such a Nb/SiO_2/Nb microstrip loss test device which contains several mm- wave resonators with f_r~100 GHz and measured it at 30 mK. All the resonators have shown internal quality factor Qi~500–2000, suggesting a loss tangent of ~5×10^(−4)−2×10^(−3) for the SiO_2 in use. For comparison, we have also fabricated a 5 GHz microstrip resonator on the same chip and measured it with a network analyzer. The loss tangent at 5 GHz derived from fitting the f_0 and Q data to the two-level system (TLS) model is 6×10^(−4), about the same as from the mm-wave measurement. This suggests that the loss at both microwave and mm-wave frequencies is probably dominated by the TLS in SiO_2. Our results are of direct interest to mm/submm direct detection applications which use microstrip transmission lines (such as antenna-coupled MKIDs and transition-edge sensors), and other applications (such as on-chip filters). Our measurement technique is applicable up to approximately 1 THz and can be used to investigate a range of dielectrics

Wind Farm Grid Integration Architecture using Unified Expandable Power Converter

IEEE This paper proposes a novel unified expandable low switch power electronic converter architecture for grid integration of direct drive variable speed wind turbine (VSWT) system using permanent magnet synchronous generator (PMSG). The proposed unified expandable power converter (UEPC) can interface two or more bidirectional output ports such as wind generators, energy storages and grid. The size of the power converter is compact because of low number of power electronic switches and protection devices and its architecture is easily expandable to accommodate more outputs, i.e., in this case, the wind turbines. A generalized sequential space vector modulation technique is developed based on the operational principle of the proposed converter to control of the outputs autonomously in order to track maximum power point for individual VSWTSs driven PMSG's. It is expected that the proposed approach will reduce the cost of power electronic converters in a wind farm compared to both AC- and DC-link based topologies, which are available for the momen

Microwave Crosstalk in Lumped Element Far-IR MKIDs

We have made close-packed far-infrared MKID arrays with ~ 250 pixels using TiN on silicon. Measurements show a large scatter in quality factor arising from crosstalk. This is confirmed by pump-probe experiments and EM simulations. Our new shielded resonator designs show very low crosstalk levels

NOVEL CONTROL STRATEGY FOR GRID-CONNECTED PHOTOVOLTAIC ARRAY

In this paper, the configuration of the PV generation system, the dynamic model for PV modules and its power electronic interfacing have been presented. A novel control strategy for the DC-DC converter has been developed in order to extract the maximum amount of power from the PV array. Also, a novel control strategy, which is based on d-q rotating reference frame, has been proposed for the DC-AC converter. The simulation results, based on PSCAD/EMTDC, show that the novel control scheme can transfer the DC energy from PV array, compensate the power factor of AC grid and improve the dynamic behavior of grid-connected PV system

Titanium Nitride Films for Ultrasensitive Microresonator Detectors

Titanium nitride (TiNx) films are ideal for use in superconducting microresonator detectors because: a) the critical temperature varies with composition (0 < Tc < 5 K); b) the normal-state resistivity is large, \rho_n ~ 100 $\mu$Ohm cm, facilitating efficient photon absorption and providing a large kinetic inductance and detector responsivity; and c) TiN films are very hard and mechanically robust. Resonators using reactively sputtered TiN films show remarkably low loss (Q_i > 10^7) and have noise properties similar to resonators made using other materials, while the quasiparticle lifetimes are reasonably long, 10-200 $\mu$s. TiN microresonators should therefore reach sensitivities well below 10^-19 WHz^(-1/2).Comment: to be published in AP

Combined Use of Sensitivity Analysis and Hybrid Wavelet-PSO- ANFIS to Improve Dynamic Performance of DFIG-Based Wind Generation

In the past few decades, increasing growth of wind power plants causes different problems for the power quality in the grid. Normal and transient impacts of these units on the power grid clearly indicate the need to improve the quality of the electricity generated by them in the design of such systems. Improving the efficiency of the large-scale wind system is dependent on the control parameters. The main contribution of this study is to propose a sensitivity analysis approach integrated with a novel hybrid approach combining wavelet transform, particle swarm optimization and an Adaptive-Network-based Fuzzy Inference System (ANFIS) known as Wavelet-ANFIS-PSO to acquire the optimal control of Doubly-Fed Induction Generators (DFIG) based wind generation. In order to mitigate the optimization complexity, sensitivity analysis is offered to identify the Unified Dominate Control Parameters (UDCP) rather than optimization of all parameters. The robustness of the proposed approach in finding optimal parameters, and consequently achieve a high dynamic performance is confirmed on two area power system under different operating conditions

Optimal Capacitor Allocation in Radial Distribution Networks for Annual Costs Minimization Using Hybrid PSO and Sequential Power Loss Index Based Method

In the most recent heuristic methods, the high potential buses for capacitor placement are initially identified and ranked using loss sensitivity factors (LSFs) or power loss index (PLI). These factors or indices help to reduce the search space of the optimization procedure, but they may not always indicate the appropriate placement of capacitors. This paper proposes an efficient approach for the optimal capacitor placement in radial distribution networks with the aim of annual costs minimization based on the sequential placement of capacitors and calculation of power loss index. In the proposed approach, initially, the number of capacitors location is estimated using the total reactive power demand and the average range of capacitors available in the market. Then, the high potential buses can be identified using sequential power loss index-based method. This method leads to achieve the optimal or near optimal locations for the capacitors and decrease the search space of the optimization procedure significantly. The particle Swarm Optimization (PSO) algorithm takes the final decision for the optimum size and location of capacitors. To evaluate the efficiency of the conducted approach, it is tested on several well-known distribution networks, and the results are compared with those of existing methods in the literature. The comparisons verify the effectiveness of the proposed method in producing fast and optimal solutions