2,594 research outputs found
Data compression techniques applied to high resolution high frame rate video technology
An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended
Spatial Learning and Action Planning in a Prefrontal Cortical Network Model
The interplay between hippocampus and prefrontal cortex (PFC) is fundamental to
spatial cognition. Complementing hippocampal place coding, prefrontal
representations provide more abstract and hierarchically organized memories
suitable for decision making. We model a prefrontal network mediating
distributed information processing for spatial learning and action planning.
Specific connectivity and synaptic adaptation principles shape the recurrent
dynamics of the network arranged in cortical minicolumns. We show how the PFC
columnar organization is suitable for learning sparse topological-metrical
representations from redundant hippocampal inputs. The recurrent nature of the
network supports multilevel spatial processing, allowing structural features of
the environment to be encoded. An activation diffusion mechanism spreads the
neural activity through the column population leading to trajectory planning.
The model provides a functional framework for interpreting the activity of PFC
neurons recorded during navigation tasks. We illustrate the link from single
unit activity to behavioral responses. The results suggest plausible neural
mechanisms subserving the cognitive “insight” capability originally
attributed to rodents by Tolman & Honzik. Our time course analysis of neural
responses shows how the interaction between hippocampus and PFC can yield the
encoding of manifold information pertinent to spatial planning, including
prospective coding and distance-to-goal correlates
Digital Image Access & Retrieval
The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio
How Much Method-in-Use Matters? A Case Study of Agile and Waterfall Software Projects and their Design Routine Variation
Development methods are rarely followed to the letter, and, consequently, their effects are often in doubt. At the same time, information systems scholars know little about the extent to which a given method truly influences software design and its outcomes. In this paper, we approach this gap by adopting a routine lens and using a novel methodological approach. Theoretically, we treat methods as (organizational) ostensive routine specifications and deploy routine construct as a feasible unit of analysis to analyze the effects of a method on actual, “performed” design routines. We formulated a research framework that identifies method, situation fitness, agency, and random noise as main sources of software design routine variation. Empirically, we applied the framework to examine the extent to which waterfall and agile methods induce variation in software design routines. We trace-enacted design activities in three software projects in a large IT organization that followed an object-oriented waterfall method and three software projects that followed an agile method and then analyzed these traces using a mixed-methods approach involving gene sequencing methods, Markov models, and qualitative content analysis. Our analysis shows that, in both cases, method-induced variation using agile and waterfall methods accounts for about 40% of all activities, while the remaining 60% can be explained by a designer’s personal habits, the project’s fitness conditions, and environmental noise. Generally, the effect of method on software design activities is smaller than assumed and the impact of designer and project conditions on software processes and outcomes should thus not be understated
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