The Tea Party

A magic trick

Yours Truly: And Other Ways of Saying I\u27m Still Here Under The Rubble Of This Exploded Building

In my digital painting, Mount Culling, 2019, a mound of objects sits on a pile of white rocks that protrudes from a watery plane. The surface of the plane stretches back to the horizon. The head of a bull in the center, a broken-down van with its rear end ripped off sits as if crashed on the rocks. A man’s head, eyes closed in restful repose is large and sculpture like, making the other objects seem like toys. The head is an industrial hue of orange-yellow on the edge of the rocks half sunk into a black and oil slick, reflective plane. I respond to generational gaps of material use within our environment and how their material ideologies, based on historical context, globalization and business ethics, reveal a nihilistic response to our current environmental crisis. I gather landscapes from around the world sorted in folders separated by its ground type. Grass fields, dirt roads, forest floors, rocky surfaces, etc. are sorted and collected for use. I choose figures to be used, scanned men and women who serve my purpose, my manipulative needs. I sort through rare artifacts, laser scanned with hi-resolution textures by international museum study interns and uploaded for educational purposes. I find models of broken down cars, cheeseburgers, lamps, bullheads, forks, spoons, etc. The possibilities are endless. My goal is to build 3D asset collages built in an x-y-z grid, scaled, subdivided, extruded and adjusted for visual acuity

Direct Digital-to-RF Conversion for Mobile-Phone Basestation Applications using Bandpass Sigma Delta Modulation

Sigma-delta modulator based digital-to-analog converters (DAC) have offered low-frequency designers a highly linear, high resolution data converter architecture that is highly amenable to integration with complex digital systems. Increasingly these data converters have been used to deliver all the power needed. In wireless applications, it is increasingly desirable to apply low-frequency sigma-delta techniques to RF signals and try to achieve similar benefits. In this paper we discuss the unique challenges that DACs in mobile phone basestations must satisfy and we present a flexible bandpass sigmadelta modulator architecture that can satisfy these criteria

Using High Pass Sigma-Delta Modulation for Class-S Power Amplifiers

Switching power amplifiers offer the potential for superior efficiencies if used at radio frequencies. However many existing bandpass architectures require a switching frequency four times that of the signal, making implementation difficult. In this paper we propose to use a high-pass sigma-delta modulator to reduce the switching rate to only twice of the signal. We will present a solution to the problem of the reflected image and demonstrate it’s viability for use in mobile telephony

Measurement-Based Evaluation Of Google/Apple Exposure Notification API For Proximity Detection in a Commuter Bus

We report on the results of a measurement study carried out on a commuter bus in Dublin, Ireland using the Google/Apple Exposure Notification (GAEN) API. This API is likely to be widely used by Covid-19 contact tracing apps. Measurements were collected between 60 pairs of handset locations and are publicly available. We find that the attenuation level reported by the GAEN API need not increase with distance between handsets, consistent with there being a complex radio environment inside a bus caused by the metal-rich environment. Changing the people holding a pair of handsets, with the location of the handsets otherwise remaining unchanged, can cause variations of +/-10dB in the attenuation level reported by the GAEN API. Applying the rule used by the Swiss Covid-19 contact tracing app to trigger an exposure notification to our bus measurements we find that no exposure notifications would have been triggered despite the fact that all pairs of handsets were within 2m of one another for at least 15 mins. Applying an alternative threshold-based exposure notification rule can somewhat improve performance to a detection rate of 5% when an exposure duration threshold of 15 minutes is used, increasing to 8% when the exposure duration threshold is reduced to 10 mins. Stratifying the data by distance between pairs of handsets indicates that there is only a weak dependence of detection rate on distance

Trends in antibacterial resistance among Streptococcus pneumoniae isolated in the USA: update from PROTEKT US Years 1–4

© 2008 Jenkins et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Detecting MAC Misbehavior of IEEE 802.11 Devices within Ultra Dense Wi-Fi Networks

The widespread deployment of IEEE 802.11 has made it an attractive target for potential attackers. The latest IEEE 802.11 standard has introduced encryption and authentication protocols that primarily address the issues of confidentiality and access control. However, improving network availability in the presence of misbehaving stations has not been addressed in the standard. Existing research addresses the problem of detecting misbehavior in scenarios without overlapping cells. However, in real scenarios cells overlap, resulting in a challenging environment for detecting misbehavior. The contribution of this paper is the presentation and evaluation of a new method for detecting misbehavior in this environment. This method is based on an objective function that uses a broad range of symptoms. Simulationresultsindicatethatthisnewapproachisverysensitive to misbehaving stations in ultra dense networks

Detecting MAC Misbehavior of IEEE 802.11 Devices within Ultra Dense Wi-Fi Networks

The widespread deployment of IEEE 802.11 has made it an attractive target for potential attackers. The latest IEEE 802.11 standard has introduced encryption and authentication protocols that primarily address the issues of confidentiality and access control. However, improving network availability in the presence of misbehaving stations has not been addressed in the standard. Existing research addresses the problem of detecting misbehavior in scenarios without overlapping cells. However, in real scenarios cells overlap, resulting in a challenging environment for detecting misbehavior. The contribution of this paper is the presentation and evaluation of a new method for detecting misbehavior in this environment. This method is based on an objective function that uses a broad range of symptoms. Simulationresultsindicatethatthisnewapproachisverysensitive to misbehaving stations in ultra dense networks

Using the XML Key Management Specification (and breaking X.509 rules as you go)

Abstract. Implementing X.509 based public-key infrastructure requires following a complex set of rules to establish if a public key certificate is valid. The XML Key Management Specification has been developed as one way in which the implementation burden can be reduced by moving some of this complexity from clients and onto a server. In this paper we give a brief overview of the XML key management specification standard, and describe how, in addition to the above, this system also provides us with the means to sensibly break many of the rules specified for X.509 based public key infrastructure

Clusters of Re-used Keys

We survey the long-term cryptographic public keys, (for SSH, e-mail and HTTP protocols), on hosts that run the SMTP protocol in ten countries. We find that keys are very widely re-used across multiple IP addresses, and even autonomous systems. From one run scanning 18,268 hosts in Ireland that run at least one TLS or SSH service, approximately 53% of the hosts involved are using keys that are also seen on some other IP address. When two IP addresses share a key, then those two IP addresses are considered members of the same cluster. In the same scan we find a maximum cluster size of 1,991 hosts and a total of 1,437 clusters, mostly with relatively few hosts per cluster (median cluster size was 26.5, most common cluster size is two). In that scan, of the 54,447 host/port combinations running cryptographic protocols, we only see 20,053 unique keys (36%), indicating significant key re-use across hosts and ports. Scans in other countries demonstrate the same issue. We describe the methodology followed and the published source code and public data sources that enable researchers to replicate, validate and extend these results. Clearly, such key re-use can create undesirable security and privacy dependencies between cluster members. A range of causes for key sharing have been confirmed, including multi-homed hosts, mirroring, large-scale use of wildcard public key certificates, cloning virtual machines that already contain host keys and vendors shipping products with hard-coded or default key pairs. Discussions with local (Irish) asset-owners to better understand the reasons for key re-use and to possibly assist with improving network posture are ongoing, and we will continue to incorporate resulting findings in revisions of this article