Phase detection at the quantum limit with multi-photon Mach-Zehnder interferometry

We study a Mach-Zehnder interferometer fed by a coherent state in one input port and vacuum in the other. We explore a Bayesian phase estimation strategy to demonstrate that it is possible to achieve the standard quantum limit independently from the true value of the phase shift and specific assumptions on the noise of the interferometer. We have been able to implement the protocol using parallel operation of two photon-number-resolving detectors and multiphoton coincidence logic electronics at the output ports of a weakly-illuminated Mach-Zehnder interferometer. This protocol is unbiased and saturates the Cramer-Rao phase uncertainty bound and, therefore, is an optimal phase estimation strategy.Comment: 4 pages, 5 figures replaced fig. 1 to correct graphics bu

TMS communications hardware. Volume 2: Bus interface unit

A prototype coaxial cable bus communication system used in the Trend Monitoring System to interconnect intelligent graphics terminals to a host minicomputer is described. The terminals and host are connected to the bus through a microprocessor-based RF modem termed a Bus Interface Unit (BIU). The BIU hardware and the Carrier Sense Multiple Access Listen-While-Talk protocol used on the network are described

The Display Protocol. A Reference for the Protocol

The Display Protocol is a unified graphics system for use at IIASA. It is based on existing systems to some extent. It consists of a device independent protocol interpreter and a small set of device dependent routines. Adapting it to a wide range of output devices requires little programmer effort. It is different from most existing systems in that it also handles devices with no graphics capability. It can convey both textual and graphic data in the same character stream. For a more detailed discussion of the design decisions that lead to the current Display Protocol see PP-79-1, "A Network Compatible Display Protocol", by B. Schweeger. Other design goals include having a clean user input side interface, meshing with UNIX design philosophy, containing ASCII as a subset, and being compact for efficient transmission over networks. This document describes the Display Protocol as it stands, not as it might be, and so may be out of date on some subjects. However, most revisions of the protocol are expected to be backward compatible. While this document may not represent what is latest with the Display Protocol, it should serve the applications writer adequately

PCODE: an efficient and reliable collective communication protocol for unreliable broadcast domain

Existing programming environments for clusters are typically built on top of a point-to-point communication layer (send and receive) over local area networks (LANs) and, as a result, suffer from poor performance in the collective communication part. For example, a broadcast that is implemented using a TCP/IP protocol (which is a point-to-point protocol) over a LAN is obviously inefficient as it is not utilizing the fact that the LAN is a broadcast medium. We have observed that the main difference between a distributed computing paradigm and a message passing parallel computing paradigm is that, in a distributed environment the activity of every processor is independent while in a parallel environment the collection of the user-communication layers in the processors can be modeled as a single global program. We have formalized the requirements by defining the notion of a correct global program. This notion provides a precise specification of the interface between the transport layer and the user-communication layer. We have developed PCODE, a new communication protocol that is driven by a global program and proved its correctness. We have implemented the PCODE protocol on a collection of IBM RS/6000 workstations and on a collection of Silicon Graphics Indigo workstations, both communicating via UDP broadcast. The experimental results we obtained indicate that the performance advantage of PCODE over the current point-to-point approach (TCP) can be as high as an order of magnitude on a cluster of 16 workstations

iSpeechNews:s real time speech news service for ubiquitous computing environment

ir-SpeechNews is a protocol to deliver a real time news service in form of speech news and lips graphics animation based on user location for Ubiquitous Computing Environment. The protocol requires 5 (five) important hybrid stacks, i.e. 1. user identity, 2. user location, 3. a real time news feeder 4. speech and dictations systems and 5. lips synchronization in responding to user activity

Investigations into Visual Statistical Inference

Statistical graphics play an important role in exploratory data analysis, model checking and diagnostics, but they are not usually associated with statistical inference. Recent developments allows inference to be applied to statistical graphics. A new method, called the lineup protocol, enables the data plot to be compared with null plots, in order to obtain estimates of statistical significance of structure. With the lineup protocol observed patterns visible in the data can be formally tested. The research conducted and described in this thesis validates the lineup protocol, examines the effects of human factors in the application of the protocol, and explains how to implement the protocol. It bridges the long existing gulf between exploratory and inferential statistics. In the validation work, additional refinement of the lineup protocol was made: methods for obtaining the power of visual tests, and p-values for particular tests are provided. A head-to-head comparison of visual inference against the best available conventional test is run for regression slope inference, using simulation experiments with human subjects. Results indicate that the visual test power is higher than the conventional test when the effect size is large, and even for smaller effect sizes, there may be some super-visual individuals who yield better performance than a conventional test. The factors that may influence the individual abilities are examined, and results suggest that demographic and geographic factors have statistically significant but practically insignificant impact. This work provides instructions on how to design human subject experiments to use Amazon\u27s Mechanical Turk to implement the lineup protocol

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model