Cut-tree construction for facility layout

The Gomory-Hu cut tree corresponding to a material flow graph provides important structural relationships to layout designers. The cut tree generation is not trivial to the programmer. In this paper, we present a simple technique which generates and constructs a cut tree of a given flow graph. The method differs from previous cut tree generation methods in the sense that its output also facilitates computer construction of the graph of the cut tree with only a few lines of additional coding, which makes its implementation attractive for computerized graph theoretic layout design approaches. The algorithm actually draws the cut tree automatically. Example graphs and the corresponding computer generated cut trees are illustrated. Also, an example is given where the cut tree information provides the optimal layout configuration.     

Spatio-temporal effects of multimedia objects storage and delivery for video-on-demand systems

As the number of video streams to be supported by a digital video delivery system (DVDS) increases, an improved understanding of the necessity for reliable and cost-efficient support for a considerable number of video streams (in the magnitude of tens of thousands), and the dependency largely on software capabilities emerges. Even in the presence of an optimal hardware configuration, or model, and associated costs, using software to exploit the underlying hardware capabilities is of paramount importance. Although a number of DVDSs have become operational, their ability to deliver the required services mainly depends on the small number of streams supported and the hardware trade-offs. It is imperative that current software developments account for the eventual scalability of the number of video streams without commensurate increase in hardware. In this paper, we present strategies for the management of video streams in order to maintain and satisfy their space and time requirements. We use a DVDS architectural model with functionally dichotomized nodes: a single-node partition is responsible for data retrieval, while the remaining partition of nodes accepts user requests, determines object locations, and routes requests through the network that connects both partitions. We present a detailed analysis of the issues related to queuing I/O requests and data buffering. The discussion includes the requirements for arranging and scheduling I/O requests and data buffers, with the objective of guaranteeing the required data availability rates for continuous media display.     

Release of reduced inorganic selenium species into waters by the green fresh water algae Chlorella vulgaris

The common green fresh water algae Chlorella vulgaris was exposed to starting concentrations of 10 μg/L selenium in the form of selenate, selenite, or selenocyanate (SeCN(-)) for nine days in 10% Bold's basal medium. Uptake of selenate was more pronounced than that of selenite, and there was very little uptake of selenocyanate. Upon uptake of selenate, significant quantities of selenite and selenocyanate were produced by the algae and released back into the growth medium; no selenocyanate was released after selenite uptake. Release of the reduced metabolites after selenate exposure appeared to coincide with increasing esterase activity in solution, indicating that cell death (lysis) was the primary emission pathway. This is the first observation of biotic formation of selenocyanate and its release into waters from a nonindustrial source. The potential environmental implications of this laboratory observation are discussed with respect to the fate of selenium in impacted aquatic systems, the ecotoxicology of selenium bioaccumulation, and the interpretation of environmental selenium speciation data generated, using methods incapable of positively identifying reduced inorganic selenium species, such as selenocyanate.     

Design and Configuration Rationales for Digital Video Storage and Delivery Systems

Recent advances in computing technology have brought multimedia information processing to prominence. The ability to digitize, store, retrieve, process, and transport analog information in digital form has changed the dimensions of information handling. Several architectural and network configurations have been proposed for efficient and reliable digital video delivery systems. However, these proposals succeed only in addressing subsets of the whole problem. In this paper, we discuss the characteristics of video services. These include Cable Television, Pay-Per-View, and Video Repository Centers. We also discuss requirements for Video On Demand services. With respect to these video services, we analyze two important video properties: image quality and response time. We discuss and present configurations of a Digital Video Delivery System (DVDS) from three general system components - servers, clients, and connectivities. Pertinent issues in developing each component are also analyzed. We also present an architecture of a DVDS that can support the various functionalities that exist in the various video services. Lastly, we discuss data allocation strategies which impact performance of interactive video on demand (IVOD). We present preliminary results from a study using a limited form of mirroring to support high performance IVOD.     

Hospital ward policy and patients' sleep patterns: A multiple baseline study.

Altered sleep–wake and nap policies on 3 inpatient psychiatric wards housing 321 veterans (aged 30–45 yrs). Across a 111-day period, daytime naps were eliminated and a standard wake-up time was established sequentially across the 3 wards. Measures of average sleep onset latency (SOL), average wake time after sleep onset (WASO), and average total sleep time (TST) were obtained for each ward every night throughout the study. Results reveal consistent decreases in both SOL and WASO and consistent increases in TST across wards following the introduction of the experimental ward policy. Nonparametric analyses revealed that, for a majority of the beds on the 3 wards, sleep parameters showed improvement following the policy change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A critique of the fire test methods used to assess individual products involved in the Artane fire

Standard fire tests on individual items involved in the Artane fire in an attempt to investigate their fire performance were found to be unsuitable. The reasons for this and for adopting an ad hoc approach are discussed.     

Grouping knowledge-base data into distributable clusters

Knowledge-base data are constructed from domains and subdomains of specific problem or application areas. Usually, the domains are not necessarily distinct because the original problem may have many interrelated components. As a result, the processing of the data becomes lengthy and windable. However, KB data can be reorganized into groups or clusters using some common relational information of the data objects. The reorganization process isolates the data and localizes the interdependency within the clusters, leaving weak linkages between clusters. Therefore, the clusters offer opportunities for mapping the data into distributed or parallel processing environments to facilitate a computational efficiency. The focus of this paper is on methods for structuring, partitioning, and clustering KB data for distributed computations.     

Great expectations: a predictive processing account of automobile driving

Predictive processing has been proposed as a unifying framework for understanding brain function, suggesting that cognition and behaviour can be fundamentally understood based on the single principle of prediction error minimisation. According to predictive processing, the brain is a statistical organ that continuously attempts get a grip on states in the world by predicting how these states cause sensory input and minimising the deviations between the predicted and actual input. While these ideas have had a strong influence in neuroscience and cognitive science, they have so far not been adopted in applied human factors research. The present paper represents a first attempt to do so, exploring how predictive processing concepts can be used to understand automobile driving. It is shown how a framework based on predictive processing may provide a novel perspective on a range of driving phenomena and offer a unifying framework for traditionally disparate human factors models.     

Changes in stuttering frequency as a function of various intervals of delayed auditory feedback.

5 different intervals of delayed auditory feedback (DAF) were presented to 6 severe stutterers while they read aloud. Results indicate that the continuous presentation of DAF significantly reduced stuttering frequency. Fluency enhancement was generally greatest during the shortest DAF intervals tested. No evidence was found for the carryover of fluency generated by DAF into the period immediately following Ss' experience on DAF. Results are consistent with a view that stuttering is based on a defect in the processing of auditory feedback. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

CDC behavioral interventions.

Comments on the review by J. A. Kelly et al (see record 1994-10963-001) regarding the need to facilitate the behavioral changes necessary to prevent HIV transmission. Three projects are described that reflect the operational research agenda proposed by Kelly et al and are being carried out by the Behavioral and Prevention Research Branch in the Division of Sexually Transmitted Diseases/HIV Prevention at the Centers for Disease Control and Prevention (CDC). (PsycINFO Database Record (c) 2010 APA, all rights reserved)