151,982 research outputs found
Optimizing for confidence - Costs and opportunities at the frontier between abstraction and reality
Is there a relationship between computing costs and the confidence people
place in the behavior of computing systems? What are the tuning knobs one can
use to optimize systems for human confidence instead of correctness in purely
abstract models? This report explores these questions by reviewing the
mechanisms by which people build confidence in the match between the physical
world behavior of machines and their abstract intuition of this behavior
according to models or programming language semantics. We highlight in
particular that a bottom-up approach relies on arbitrary trust in the accuracy
of I/O devices, and that there exists clear cost trade-offs in the use of I/O
devices in computing systems. We also show various methods which alleviate the
need to trust I/O devices arbitrarily and instead build confidence
incrementally "from the outside" by considering systems as black box entities.
We highlight cases where these approaches can reach a given confidence level at
a lower cost than bottom-up approaches.Comment: 11 pages, 1 figur
Principles of effective literacy practice for EAL students in New Zealand classrooms.
The New Zealand Ministry of Education has recently identified the need for teachers to be prepared to meet the needs of English as an additional language (EAL)Ā² students in New Zealand schools more effectively. This paper offers a number of principles to guide policy, practice and teacher development. The paper draws on Alton-Lee's (2003) best evidence synthesis of quality teaching for diverse students, and Franken and McComish's (2003a, 2003b) observations and analysis of provisions for EAL students in New Zealand schools. The principles, grounded in second language and literacy acquisition research, point to the need to provide particular enabling conditions for the literacy development of EAL students if they are to achieve as well as their English-speaking peers
The Anatomy and Facets of Dynamic Policies
Information flow policies are often dynamic; the security concerns of a
program will typically change during execution to reflect security-relevant
events. A key challenge is how to best specify, and give proper meaning to,
such dynamic policies. A large number of approaches exist that tackle that
challenge, each yielding some important, but unconnected, insight. In this work
we synthesise existing knowledge on dynamic policies, with an aim to establish
a common terminology, best practices, and frameworks for reasoning about them.
We introduce the concept of facets to illuminate subtleties in the semantics of
policies, and closely examine the anatomy of policies and the expressiveness of
policy specification mechanisms. We further explore the relation between
dynamic policies and the concept of declassification.Comment: Technical Report of publication under the same name in Computer
Security Foundations (CSF) 201
Tracing and Debugging of Lazy Functional Programs - A Comparative Evaluation of Three Systems
In this paper we compare three systems for tracing and debugging Haskell programs: Freja, the Redex Trail System and Hood. We identify the similarities and differences of these systems and we evaluate their usefulness in practice by applying them to a number of small to medium programs in which errors had deliberately been introduced
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