Operational viewpoint of the X-29A digital flight control system

In the past few years many flight control systems have been implemented as full-authority, full-time digital systems. The digital design has allowed flight control systems to make use of many enhanced elements that are generally considered too complex to implement in an analog system. Examples of these elements are redundant information exchanged between channels to allow for continued operation after multiple failures and multiple variable gain schedules to optimize control of the aircraft throughout its flight envelope and in all flight modes. The introduction of the digital system for flight control also created the problem of obtaining information from the system in an understandable and useful format. This paper presents how the X-29A was dealt with during its operations at NASA Ames-Dryden Flight Research Facility. A brief description of the X-29A control system, a discussion of the tools developed to aid in daily operations, and the troubleshooting of the aircraft are included

A Comparative Study of Scheduling Techniques for Multimedia Applications on SIMD Pipelines

Parallel architectures are essential in order to take advantage of the parallelism inherent in streaming applications. One particular branch of these employ hardware SIMD pipelines. In this paper, we analyse several scheduling techniques, namely ad hoc overlapped execution, modulo scheduling and modulo scheduling with unrolling, all of which aim to efficiently utilize the special architecture design. Our investigation focuses on improving throughput while analysing other metrics that are important for streaming applications, such as register pressure, buffer sizes and code size. Through experiments conducted on several media benchmarks, we present and discuss trade-offs involved when selecting any one of these scheduling techniques.Comment: Presented at DATE Friday Workshop on Heterogeneous Architectures and Design Methods for Embedded Image Systems (HIS 2015) (arXiv:1502.07241

A new adaptive neural network and heuristics hybrid approach for job-shop scheduling

Copyright @ 2001 Elsevier Science LtdA new adaptive neural network and heuristics hybrid approach for job-shop scheduling is presented. The neural network has the property of adapting its connection weights and biases of neural units while solving the feasible solution. Two heuristics are presented, which can be combined with the neural network. One heuristic is used to accelerate the solving process of the neural network and guarantee its convergence, the other heuristic is used to obtain non-delay schedules from the feasible solutions gained by the neural network. Computer simulations have shown that the proposed hybrid approach is of high speed and efficiency. The strategy for solving practical job-shop scheduling problems is provided.This work is supported by the National Nature Science Foundation (No. 69684005) and National High -Tech Program of P. R. China (No. 863-511-9609-003)

Interactive flight control system analysis program

A summary of the development, use, and documentation of the interactive software (DIGIKON IV) for flight control system analyses is presented. A list of recommendations for future development is also included

Conducting of the linkage between information systems strategy (ISS) and Operation Strategy in the case of 'X' Airlines in Arabic gulf country

The integration of IS/IT strategy with other business units' strategies has become an important issue. The layer of integration through business strategies requires an explanation of interrelationships so that business objectives appropriate to the available resources and market conditions can be established. This study is a comprehensive examination of the relationship between IS and operational strategy at 'X' Airlines. Operation is considered one of the core activities at 'X'. In this study, the researcher employs a qualitative method, presenting the literature on IS integration and utilising a case study approach to understand the how and why of using IS at 'X'. This study discusses the existing frameworks, both theoretical and practical, for IS strategic integration. The results show that there are strong relationships but as a traditional kind of back office support of IS for operational strategy within 'X'

Acceptability of medical digital libraries

Evidenced-based medicine has increased the importance of quick accessibility to reputable, upto-date information. Web-accessible digital libraries (DLs) on the wards can address the demand for such information. The use and acceptability of these resources has, however, been lower than expected due to a poor understanding of the context of use. To appreciate the social and organizational impacts of ward-accessible DLs for clinicians, results of a study within a large London-based hospital are presented. In-depth interviews and focus groups with 73 clinicians (from pre-registration nurses to surgeons) were conducted, and the data analysed using the grounded theory method. It was found that clinical social structures interact with inadequate training provision (for senior clinicians), technical support and DL usability to produce a knowledge gap between junior and senior staff, resulting in information – and technology – hoarding behaviours. Findings also detail the perceived effectiveness of traditional and digital libraries and the impact of clinician status on information control and access. One important conclusion is that increased DL usability and adequate support and training for senior clinicians would increase perceptions of DLs as support for, rather than replacement of, their clinical expertise. © 2002, The Continuum Publishing Group Ltd. All rights reserved

Unbounded Human Learning: Optimal Scheduling for Spaced Repetition

In the study of human learning, there is broad evidence that our ability to retain information improves with repeated exposure and decays with delay since last exposure. This plays a crucial role in the design of educational software, leading to a trade-off between teaching new material and reviewing what has already been taught. A common way to balance this trade-off is spaced repetition, which uses periodic review of content to improve long-term retention. Though spaced repetition is widely used in practice, e.g., in electronic flashcard software, there is little formal understanding of the design of these systems. Our paper addresses this gap in three ways. First, we mine log data from spaced repetition software to establish the functional dependence of retention on reinforcement and delay. Second, we use this memory model to develop a stochastic model for spaced repetition systems. We propose a queueing network model of the Leitner system for reviewing flashcards, along with a heuristic approximation that admits a tractable optimization problem for review scheduling. Finally, we empirically evaluate our queueing model through a Mechanical Turk experiment, verifying a key qualitative prediction of our model: the existence of a sharp phase transition in learning outcomes upon increasing the rate of new item introductions.Comment: Accepted to the ACM SIGKDD Conference on Knowledge Discovery and Data Mining 201