Computer determines high-frequency phase stability

Determination of phase stability of a high frequency signal using a computer is accomplished by a circuit using two auxiliary oscillators, multipliers and low-pass filters in cross correlation with the oscillator producing the signal of interest

The basic characteristics of hybrid aircraft

The transportation of very heavy or very bulky loads by airships, and the ability to carry out extended duration flights at low speeds and low costs was studied. Structural design and weight factors for airship construction are examined. The densities of various light gases to be used in airships are given, along with their lifting capacities. The aerodynamic characteristics of various airship configurations was studied. Propulsion system requirements for airships are briefly considered

Digital system accurately controls velocity of electromechanical drive

Digital circuit accurately regulates electromechanical drive mechanism velocity. The gain and phase characteristics of digital circuits are relatively unimportant. Control accuracy depends only on the stability of the input signal frequency

Apparatus for controlling the velocity of an electromechanical drive for interferometers and the like Patent

Describing device for velocity control of electromechanical drive mechanism of scanning mirror of interferomete

Designing Interfaces to Support Collaboration in Information Retrieval

Information retrieval systems should acknowledge the existence of collaboration in the search process. Collaboration can help users to be more effective in both learning systems and in using them. We consider some issues of viewing interfaces to information retrieval systems as collaborative notations and how to build systems that more actively support collaboration. We describe a system that embodies just one kind of explicit support; a graphical representation of the search process that can be manipulated and discussed by the users. By acknowledging the importance of other people in the search process, we can develop systems that not only improve help-giving by people but which can lead to a more robust search activity, more able to cope with, and indeed exploit, the failures of any intelligent agents used

Usability discussions in open source development

The public nature of discussion in open source projects provides a valuable resource for understanding the mechanisms of open source software development. In this paper we explore how open source projects address issues of usability. We examine bug reports of several projects to characterise how developers address and resolve issues concerning user interfaces and interaction design. We discuss how bug reporting and discussion systems can be improved to better support bug reporters and open source developers

Recommendation, collaboration and social search

This chapter considers the social component of interactive information retrieval: what is the role of other people in searching and browsing? For simplicity we begin by considering situations without computers. After all, you can interactively retrieve information without a computer; you just have to interact with someone or something else. Such an analysis can then help us think about the new forms of collaborative interactions that extend our conceptions of information search, made possible by the growth of networked ubiquitous computing technology. Information searching and browsing have often been conceptualized as a solitary activity, however they always have a social component. We may talk about 'the' searcher or 'the' user of a database or information resource. Our focus may be on individual uses and our research may look at individual users. Our experiments may be designed to observe the behaviors of individual subjects. Our models and theories derived from our empirical analyses may focus substantially or exclusively on an individual's evolving goals, thoughts, beliefs, emotions and actions. Nevertheless there are always social aspects of information seeking and use present, both implicitly and explicitly. We start by summarizing some of the history of information access with an emphasis on social and collaborative interactions. Then we look at the nature of recommendations, social search and interfaces to support collaboration between information seekers. Following this we consider how the design of interactive information systems is influenced by their social elements

A comparison of eligibility trace and momentum on SARSA in continuous state- and action-space

Here the Newton’s Method direct action selection approach to continuous action-space reinforcement learning is extended to use an eligibility trace. This is then compared to the momentum term approach from the literature in terms of the update equations and also the success rate and number of trials required to train on two variants of the simulated Cart-Pole benchmark problem. The eligibility trace approach achieves a higher success rate with a far wider range of parameter values than the momentum approach and also trains in fewer trials on the Cart-Pole problem

A comparison of action selection methods for implicit policy method reinforcement learning in continuous action-space

In this paper I investigate methods of applying reinforcement learning to continuous state- and action-space problems without a policy function. I compare the performance of four methods, one of which is the discretisation of the action-space, and the other three are optimisation techniques applied to finding the greedy action without discretisation. The optimisation methods I apply are gradient descent, Nelder-Mead and Newton's Method. The action selection methods are applied in conjunction with the SARSA algorithm, with a multilayer perceptron utilized for the approximation of the value function. The approaches are applied to two simulated continuous state- and action-space control problems: Cart-Pole and double Cart-Pole. The results are compared both in terms of action selection time and the number of trials required to train on the benchmark problems