490 research outputs found

    The Impact of IPv6 on Penetration Testing

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    In this paper we discuss the impact the use of IPv6 has on remote penetration testing of servers and web applications. Several modifications to the penetration testing process are proposed to accommodate IPv6. Among these modifications are ways of performing fragmentation attacks, host discovery and brute-force protection. We also propose new checks for IPv6-specific vulnerabilities, such as bypassing firewalls using extension headers and reaching internal hosts through available transition mechanisms. The changes to the penetration testing process proposed in this paper can be used by security companies to make their penetration testing process applicable to IPv6 targets

    Phased-Array antenna beam squinting related to frequency dependency of delay circuits

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    Abstract-Practical time delay circuits do not have a perfectly linear phase-frequency characteristic. When these delay circuits are applied in a phased-array system, this frequency dependency shows up as a frequency dependent beam direction (“beam squinting”). This paper quantifies beam squinting for a linear one-dimensional phased array with equally spaced antenna elements. The analysis is based on a (frequency-dependent) linear approximation of the phase transfer function of the delay circuit. The resulting relation turns out to be invariant for cascaded cells. Also a method is presented to design time-delay circuits to meet a maximum phased-array beam squinting requirement

    The introduction of deductibles for prescription drugs in a national health insurance: Compulsory or voluntary?

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    We consider a situation of full insurance coverage for prescription drugs where, at a certain point in time, people are given the opportunity to take a deductible in exchange for a lower premium. Four determinants of this premium reduction can be considered: expected out-of-pocket payments, adverse selection effects, moral hazard effects, and administration costs. The purpose of this study is to analyse the first two determinants. Survey data of 17 242 insureds in the Netherlands have been used for this research. Results show that the expected out-of-pocket expenditures in case of a certain deductible amount depend strongly on age and gender. People in poor health could be given a larger premium discount if they would take a deductible than those in good health. This implies that a uniform premium discount would induce adverse selection. The effects of such selection have been simulated by using a survey question about the preference to take a general deductible. If the premium reductions for policies with a deductible are adjusted for age and gender, the selection effect will halve but will still be substantial. We conclude that, in the situation considered here, it is largely immaterial whether deductibles are compulsory or voluntary, provided premium reductions are allowed to depend on relevant risk factors

    Selection Incentives for Health Insurers in the Presence of Sophisticated Risk Adjustment

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    This article analyzes selection incentives for insurers in the Dutch basic health insurance market, which operates with community-rated premiums and sophisticated risk adjustment. Selection incentives result from the interplay of three market characteristics: possible actions by insurers, consumer response to these actions, and predictable variation in profitability of insurance contracts. After a qualitative analysis of the first two characteristics our prima

    A 4-element phased-array system with simultaneous spatial- and frequency-domain filtering at the antenna inputs

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    To reject strong interference in excess of 0 dBm, a 4- element LO-phase shifting phased-array receiver with 8-phase passive mixers terminated by baseband capacitors is presented. The passive mixers upconvert both the spatial and frequency domain filtering from baseband to RF, hence realizing blocker suppression directly at the antenna inputs. A comprehensive mathematical model provides a set of closed-form equations describing the spatial and frequency domain filtering including imperfections. A prototype is realized in 28 nm CMOS. It exploits third harmonic reception to achieve a wide RF-frequency range from 0.6–4.5 GHz at 34–119 mW power dissipation, while also providing impedance matching. Out of the band/beam, a 1 dB-compression point as high as +12/+10 dBm has been measured. The 1-element noise figure over the RF-frequency range is 4–6.3 dB, while in-beam/band IIP3 values of 0– +2.6 dBm are measured. This proposed technique can be instrumental to make RF receivers more robust for interference, while still being flexibly tunable in frequency

    A 7-8 GHz serrodyne modulator in SiGe for MIMO signal generation

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    An 8-bit 360o sawtooth modulated phase shifter is used to apply very small frequency offsets to RF signals between 7 and 8 GHz. Offsets between 6 Hz and 10MHz can be obtained. Such frequency offsets can be used to generate orthogonal signals, which are required in e.g. MIMO applications. Each undesired frequency component is suppressed to below -30 dBc. The phase modulator is realized in a 250 nm SiGe BICMOS technology
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