AT&T Labs

About: AT&T Labs is a based out in . It is known for research contribution in the topics: Network packet & The Internet. The organization has 1879 authors who have published 5595 publications receiving 483151 citations.

A differential detection scheme for transmit diversity

Abstract: We present a transmission scheme for exploiting diversity given by two transmit antennas when neither the transmitter nor the receiver has access to channel state information. The new detection scheme can use equal energy constellations and encoding is simple. At the receiver, decoding is achieved with low decoding complexity. The transmission provides full spatial diversity and requires no channel state side information at the receiver. The scheme can be considered as the extension of differential detection schemes to two transmit antennas.

Visual Domain Adaptation: A survey of recent advances

Abstract: In pattern recognition and computer vision, one is often faced with scenarios where the training data used to learn a model have different distribution from the data on which the model is applied. Regardless of the cause, any distributional change that occurs after learning a classifier can degrade its performance at test time. Domain adaptation tries to mitigate this degradation. In this article, we provide a survey of domain adaptation methods for visual recognition. We discuss the merits and drawbacks of existing domain adaptation approaches and identify promising avenues for research in this rapidly evolving field.

The design and analysis of graphical passwords

Abstract: In this paper we propose and evaluate new graphical password schemes that exploit features of graphical input displays to achieve better security than text-based passwords. Graphical input devices enable the user to decouple the position of inputs from the temporal order in which those inputs occur, and we show that this decoupling can be used to generate password schemes with substantially larger (memorable) password spaces. In order to evaluate the security of one of our schemes, we devise a novel way to capture a subset of the "memorable" passwords that, we believe, is itself a contribution. In this work we are primarily motivated by devices such as personal digital assistants (PDAs) that offer graphical input capabilities via a stylus, and we describe our prototype implementation of one of our password schemes on such a PDA, namely the Palm PilotTM.

Gigascope: a stream database for network applications

Abstract: We have developed Gigascope, a stream database for network applications including traffic analysis, intrusion detection, router configuration analysis, network research, network monitoring, and performance monitoring and debugging. Gigascope is undergoing installation at many sites within the AT&T network, including at OC48 routers, for detailed monitoring. In this paper we describe our motivation for and constraints in developing Gigascope, the Gigascope architecture and query language, and performance issues. We conclude with a discussion of stream database research problems we have found in our application.

The platform for privacy preferences

Abstract: nternet users are concerned about the privacy of information they supply to Web sites, not only in terms of personal data, but information that Web sites may derive by tracking their online activities [7]. Many online privacy concerns arise because it is difficult for users to obtain information about actual Web site information practices. Few Web sites post privacy policies, 1 and even when they are posted, users do not always find them trustworthy or understandable. Thus, there is often a one-way mirror effect: Web sites ask users to provide personal information, but users have little knowledge about how their information will be used. Understandably, this lack of knowledge leads to confusion and mistrust. The WorldWide Web Consortium (W3C)'s Platform for Privacy Preferences Project (P3P) provides a framework for informed online interactions. The goal of P3P is to enable users to exercise preferences over Web site privacy practices at the Web sites. P3P applications will allow users to be informed about Web site practices , delegate decisions to their computer agent when they wish, and tailor relationships with specific sites. We believe users' confidence in online transactions will increase when they are presented with meaningful information and choices about Web site privacy practices. P3P is not a silver bullet; it is complemented by other technologies as well as regulatory and self-regulatory approaches to privacy. Some technologies have the ability to technically preclude practices that may be unacceptable to a user. For example, digital cash, anonymizers, and encryp-tion limit the information the recipient or eaves-droppers can collect during an interaction. Laws and industry guidelines codify and enforce expectations regarding information practices as the default or baseline for interactions. A compelling feature of P3P is that localized decision making enables flexibility in a medium that encompasses diverse preferences, cultural norms, and regulatory jurisdictions. However, for P3P to be effective, users must be willing and able to make meaningful decisions when presented with disclosures. This requires the existence of easy-to-use tools that allow P3P P Pr ri iv va ac cy y P Pr re ef fe er re en nc ce es s Web sites can bolster user confidence by clarifying their privacy practices upfront, allowing visitors to become active players in the decision-making process. 49 users to delegate much of the information processing and decision making to their computer agents when they wish, as well as a framework promoting the use …