The Case of Richard Tomlinson: The Spy Who E-mailed Me

This article considers the issues raised by the Richard Tomlinson affair. The authors discuss the following implications: First, the effective regulation and control of the Intelligence Services, concentrating upon the terms of Official Secrets legislation. Second, adequate legal safeguards for the internet. The authors discuss, inter alia , the problems of jurisdictional control, international regulation and technical possibilities for control. Finally, the authors assess the impact of the United Kingdom Government's proposals for a Freedom of Information Act and their impact upon the internet and the Intelligence Services. The authors contend that the Official Secrets Act 1989 is still in need of reform, regulation of the internet requires a paradigm shift in attitude, from all concerned and that the proposed Freedom of Information Bill requires overhauling.     

Characterizations of reduction classes modulo oracle conditions

It is known that nondeterministic polynomial time truth-table reducibility is exactly the same as nondeterministic polynomial time Turing reducibility. Here we study the standard nondeterministic reducibilities (conjunctive, bounded truth-table, bounded positive truth-table, and many-one) and show that each is a restriction of nondeterministic polynomial time Turing reducibility corresponding to acceptance modulo a set of oracle conditions. Then we show that the reduction classes of these reducibilities are classes of formal languages and as such have language theoretic characterization theorems. The same program is carried out for polynomial space.This research was supported in part by the National Science Foundation under Grants MCS77-23493, MSC80-11979, MCS81-20263, and MCS83-12472. The work of the second author was also supported by the United States-Israel Educational Foundation (Fulbright Award).     

Dynamical synapses enhance neural information processing: gracefulness, accuracy, and mobility

Experimental data have revealed that neuronal connection efficacy exhibits two forms of short-term plasticity: short-term depression (STD) and short-term facilitation (STF). They have time constants residing between fast neural signaling and rapid learning and may serve as substrates for neural systems manipulating temporal information on relevant timescales. This study investigates the impact of STD and STF on the dynamics of continuous attractor neural networks and their potential roles in neural information processing. We find that STD endows the network with slow-decaying plateau behaviors: the network that is initially being stimulated to an active state decays to a silent state very slowly on the timescale of STD rather than on that of neuralsignaling. This provides a mechanism for neural systems to hold sensory memory easily and shut off persistent activities gracefully. With STF, we find that the network can hold a memory trace of external inputs in the facilitated neuronal interactions, which provides a way to stabilize the network response to noisy inputs, leading to improved accuracy in population decoding. Furthermore, we find that STD increases the mobility of the network states. The increased mobility enhances the tracking performance of the network in response to time-varying stimuli, leading to anticipative neural responses. In general, we find that STD and STP tend to have opposite effects on network dynamics and complementary computational advantages, suggesting that the brain may employ a strategy of weighting them differentially depending on the computational purpose.     

Skinner's dark year and Walden Two..

Points out that although it was offered simply as a fictional application of radical behaviorism to the design of society, Skinner's utopian novel Walden Two possessed strong emotional connotations for him. The "dark year," a period during his youth when he failed as a creative writer, displayed many earmarks of a major identity crisis. Walden Two was written during a mid-life crisis when identity issues again became highly salient for Skinner. The novel incorporated issues from both periods into its picture of an ideal society and helped him to resolve his developmental conflicts. He emerged with a restructured identity as public advocate for a behavioristic science of human conduct. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cumulating Retrieval Inhibition in Semantic and Lexical Domains.

In 3 experiments the authors examined changes in successive exemplar generation percentages within categories defined semantically (e.g., fruit-P, fruit-A, fruit-M) and by 1st letter (e.g., insect-C, sport-C, car-C), with a mixed control condition (e.g., fruit-P, insect-C, disease-M). Retrieval success declined across 12 successive items in both semantic and letter categories, with no change for the mixed condition. This retrieval inhibition is unrelated to taxonomic frequency of exemplars within either letter or semantic categorical structures. Furthermore, semantic retrieval inhibition appears to be long lasting, suggested by the decline in retrieval percentage across successive 12-item blocks in both the mixed and letter conditions. The authors suggest that different mechanisms underlie the inhibition found in the semantic (suppression) and letter (interference) conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Typing correspondence assertions for communication protocols

Woo and Lam propose correspondence assertions for specifying authenticity properties of security protocols. Prior work on checking correspondence assertions depends on model-checking and is limited to finite-state systems. We propose a dependent type and effect system for checking correspondence assertions. Since it is based on type-checking, our method is not limited to finite-state systems. This paper presents our system in the simple and general setting of the π-calculus. We show how to type-check correctness properties of example communication protocols based on secure channels. In a related paper, we extend our system to the more complex and specific setting of checking cryptographic protocols based on encrypted messages sent over insecure channels.     

Constraint-Based Design of Embedded Intelligent Systems

Substantial progress has been achieved using the standard Constraint Satisfaction Problem framework. However, there is a major unsolved challenge confronting the constraint research community: the constraint-based design of embedded intelligent systems. This requires a new online model of constraint satisfaction and new computational tools for specifying, modeling, verifying and implementing constraint-based, hybrid, intelligent systems, such as robots. The Constraint Net model of Zhang and Mackworth allows the design of hybrid intelligent systems as situated robots: modeling the robot and the environment symmetrically as dynamic systems. If the robot's perceptual and control systems are designed as constraint-satisfying devices then the total robotic system, consisting of the robot symmetrically coupled to the environment, can be proven correct. Some theoretical and practical advances based on this model are described, including experiments with the constraint-based design of robot soccer players.     

Improving the availability and cost-effectiveness of guidelines for guideline-users: towards a structured approach

The achievement of design and development solutions can be enhanced through consulting appropriate guidelines Although a wide range exist, frequently their full benefits are not realized by guideline-users because of the costs associated with their use. Guideline-users are people who use guidelines to support purposeful activity. Major cost drivers for guideline-users are the processes of 'selecting' appropriate guidelines and their subsequent 'translation' to an applied setting both of which can be prohibitively expensive. A strategy for producing guidelines is proposed, to minimize these costs, which is illustrated by the use of a case study concerned with the development of guidelines to assist in the production of management and administrative tools which will support project managers concerned with Human Factors Acceptance Testing. A process to support the assessment of guidelines is also proposed.     

The Challenges of Cross-Modal Translation: English-to-Sign-Language Translation in the Zardoz System

The sign languages used by deaf communities around the world represent a linguistic challenge that natural-language researchers in AI have only recently begun to take up. This challenge is particularly relevant to research in Machine Translation (MT), as natural sign languages have evolved in deaf communities into efficient modes of gestural communication, which differ from English not only in modality but in grammatical structure, exploiting a higher dimensionality of spatial expression. In this paper we describe Zardoz, an on-going AI research system that tackles the cross-modal MT problem, translating English text into fluid sign language. The paper presents an architectural overview of Zardoz, describing its central blackboard organization, the nature of its interlingual representation, and the major components which interact through this blackboard both to analyze the verbal input and generate the corresponding gestural output in one of a number of sign variants.