Digital Cinema : Opportunities and Challenges

This paper considers how the film industry might effect the transition from film to digital product. Using public sources to predict the eventual technological solutions which will prevail is problematic as no independent academic analysis appears to have been carried out. Technology companies are clearly wedded to their own solutions, pointing out flaws in competing technologies while downplaying the shortcomings of their own. Industry wide bodies that have been set up to promote d-cinema or establish standards, understandably tend to avoid taking sides and promote all solutions equally[i]. Rather than contributing further to the debate about the qualities of competing technologies or the creative merits or demerits of digital product, this paper will focus on the search for new business models in an industry wedded for over one hundred years to an analogue process. In the sections which follow it will consider- the strategies of the companies at the forefront of the technology; the financial implications associated with change; and how different territories might adapt in order to accommodate this transition. [i] Anna Wilde Mathews, Digital cinema's time is nearing. Detailed specifications are supposed to be ready early next year. The Wall Street Journal, May 25 2003

Symmetry implies independence

Given a quantum system consisting of many parts, we show that symmetry of the system's state, i.e., invariance under swappings of the subsystems, implies that almost all of its parts are virtually identical and independent of each other. This result generalises de Finetti's classical representation theorem for infinitely exchangeable sequences of random variables as well as its quantum-mechanical analogue. It has applications in various areas of physics as well as information theory and cryptography. For example, in experimental physics, one typically collects data by running a certain experiment many times, assuming that the individual runs are mutually independent. Our result can be used to justify this assumption.Comment: LaTeX, contains 4 figure

Quantum data hiding in the presence of noise

When classical or quantum information is broadcast to separate receivers, there exist codes that encrypt the encoded data such that the receivers cannot recover it when performing local operations and classical communication, but they can decode reliably if they bring their systems together and perform a collective measurement. This phenomenon is known as quantum data hiding and hitherto has been studied under the assumption that noise does not affect the encoded systems. With the aim of applying the quantum data hiding effect in practical scenarios, here we define the data-hiding capacity for hiding classical information using a quantum channel. Using this notion, we establish a regularized upper bound on the data hiding capacity of any quantum broadcast channel, and we prove that coherent-state encodings have a strong limitation on their data hiding rates. We then prove a lower bound on the data hiding capacity of channels that map the maximally mixed state to the maximally mixed state (we call these channels "mictodiactic"---they can be seen as a generalization of unital channels when the input and output spaces are not necessarily isomorphic) and argue how to extend this bound to generic channels and to more than two receivers.Comment: 12 pages, accepted for publication in IEEE Transactions on Information Theor

Device independent quantum key distribution secure against coherent attacks with memoryless measurement devices

Device independent quantum key distribution aims to provide a higher degree of security than traditional QKD schemes by reducing the number of assumptions that need to be made about the physical devices used. The previous proof of security by Pironio et al. applies only to collective attacks where the state is identical and independent and the measurement devices operate identically for each trial in the protocol. We extend this result to a more general class of attacks where the state is arbitrary and the measurement devices have no memory. We accomplish this by a reduction of arbitrary adversary strategies to qubit strategies and a proof of security for qubit strategies based on the previous proof by Pironio et al. and techniques adapted from Renner.Comment: 13 pages. Expanded main proofs with more detail, miscellaneous edits for clarit

TechNews digests: Jan - Nov 2008

TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month

Survey of LAN infrastructure and ICT equipment in schools: November 2005 to January 2006 (summary report)

Nationally representative technical audit of school infrastructure - summar