1,619 research outputs found
A Discrete Fourier Kernel and Fraenkel's Tiling Conjecture
The set B_{p,r}^q:=\{\floor{nq/p+r} \colon n\in Z \} with integers p, q, r)
is a Beatty set with density p/q. We derive a formula for the Fourier transform
\hat{B_{p,r}^q}(j):=\sum_{n=1}^p e^{-2 \pi i j \floor{nq/p+r} / q}. A. S.
Fraenkel conjectured that there is essentially one way to partition the
integers into m>2 Beatty sets with distinct densities. We conjecture a
generalization of this, and use Fourier methods to prove several special cases
of our generalized conjecture.Comment: 24 pages, 6 figures (now with minor revisions and clarifications
A Generic Storage API
We present a generic API suitable for provision of highly generic storage
facilities that can be tailored to produce various individually customised
storage infrastructures. The paper identifies a candidate set of minimal
storage system building blocks, which are sufficiently simple to avoid
encapsulating policy where it cannot be customised by applications, and
composable to build highly flexible storage architectures. Four main generic
components are defined: the store, the namer, the caster and the interpreter.
It is hypothesised that these are sufficiently general that they could act as
building blocks for any information storage and retrieval system. The essential
characteristics of each are defined by an interface, which may be implemented
by multiple implementing classes.Comment: Submitted to ACSC 200
Hypercube orientations with only two in-degrees
We consider the problem of orienting the edges of the -dimensional
hypercube so only two different in-degrees and occur. We show that this
can be done, for two specified in-degrees, if and only if an obvious necessary
condition holds. Namely, there exist non-negative integers and so that
and . This is connected to a question arising from
constructing a strategy for a "hat puzzle."Comment: 9 pages, 4 figure
Report on the XBase Project
This project addressed the conceptual fundamentals of data storage,
investigating techniques for provision of highly generic storage facilities
that can be tailored to produce various individually customised storage
infrastructures, compliant to the needs of particular applications. This
requires the separation of mechanism and policy wherever possible. Aspirations
include: actors, whether users or individual processes, should be able to bind
to, update and manipulate data and programs transparently with respect to their
respective locations; programs should be expressed independently of the storage
and network technology involved in their execution; storage facilities should
be structure-neutral so that actors can impose multiple interpretations over
information, simultaneously and safely; information should not be discarded so
that arbitrary historical views are supported; raw stored information should be
open to all; where security restrictions on its use are required this should be
achieved using cryptographic techniques. The key advances of the research were:
1) the identification of a candidate set of minimal storage system building
blocks, which are sufficiently simple to avoid encapsulating policy where it
cannot be customised by applications, and composable to build highly flexible
storage architectures 2) insight into the nature of append-only storage
components, and the issues arising from their application to common storage
use-cases
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