336 research outputs found
Agent-Based Team Aiding in a Time Critical Task
In this paper we evaluate the effectiveness of agent-based aiding in support of a time-critical team-planning task for teams of both humans and heterogeneous software agents. The team task consists of human subjects playing the role of military commanders and cooperatively planning to move their respective units to a common rendezvous point, given time and resource constraints. The objective of the experiment was to compare the effectiveness of agent-based aiding for individual and team tasks as opposed to the baseline condition of manual route planning. There were two experimental conditions: the Aided condition, where a Route Planning Agent (RPA) finds a least cost plan between the start and rendezvous points for a given composition of force units; and the Baseline condition, where the commanders determine initial routes manually, and receive basic feedback about the route. We demonstrate that the Aided condition provides significantly better assistance for individual route planning and team-based re-planning
Initial operating experience of the 12-MW La Ola photovoltaic system.
The 1.2-MW La Ola photovoltaic (PV) power plant in Lanai, Hawaii, has been in operation since December 2009. The host system is a small island microgrid with peak load of 5 MW. Simulations conducted as part of the interconnection study concluded that unmitigated PV output ramps had the potential to negatively affect system frequency. Based on that study, the PV system was initially allowed to operate with output power limited to 50% of nameplate to reduce the potential for frequency instability due to PV variability. Based on the analysis of historical voltage, frequency, and power output data at 50% output level, the PV system has not significantly affected grid performance. However, it should be noted that the impact of PV variability on active and reactive power output of the nearby diesel generators was not evaluated. In summer 2011, an energy storage system was installed to counteract high ramp rates and allow the PV system to operate at rated output. The energy storage system was not fully operational at the time this report was written; therefore, analysis results do not address system performance with the battery system in place
Hypoxia Regulates BMP4 Expression in the Murine Spleen during the Recovery from Acute Anemia
Bone marrow erythropoiesis is primarily homeostatic, producing new erythrocytes at a constant rate. However at times of acute anemia, new erythrocytes must be rapidly produced much faster than bone marrow steady state erythropoiesis. At these times stress erythropoiesis predominates. Stress erythropoiesis occurs in the fetal liver during embryogenesis and in the adult spleen and liver. In adult mice, stress erythropoiesis utilizes a specialized population of stress erythroid progenitors that are resident in the spleen. In response to acute anemia, these progenitors rapidly expand and differentiate in response to three signals, BMP4, SCF and hypoxia. In absence of acute anemic stress, two of these signals, BMP4 and hypoxia, are not present and the pathway is not active. The initiating event in the activation of this pathway is the up-regulation of BMP4 expression in the spleen.In this paper we analyze the regulation of BMP4 expression in the spleen by hypoxia. Using stromal cell lines, we establish a role for hypoxia transcription factor HIFs (Hypoxia Inducible Factors) in the transcription of BMP4. We identified putative Hypoxia Responsive Elements (HREs) in the BMP4 gene using bioinformatics. Analysis of these elements showed that in vivo, Hif2alpha binds two cis regulatory sites in the BMP4 gene, which regulate BMP4 expression during the recovery from acute anemia.These data show that hypoxia plays a key role in initiating the BMP4 dependent stress erythropoiesis pathway by regulating BMP4 expression
Celebrating 20 Years of the ExCEEd Teaching Workshop
In response to the clear need for faculty training, the American Society of Civil Engineers (ASCE) developed and funded Project ExCEEd (Excellence in Civil Engineering Education) which is celebrating its twentieth year of existence. For the past two decades, 38 ExCEEd Teaching Workshops (ETW) have been held at six different universities. The program has 910 graduates from over 267 different U.S. and international colleges and universities. The ExCEEd effort has transformed from one that relied on the grass roots support of its participants to one that is supported and embraced by department heads and deans. This paper summarizes the history of Project ExCEEd, describes the content of the ETW, assesses its effectiveness, highlights changes in the program as a result of the assessment, and outlines the future direction of the program
Usability and digital inclusion: standards and guidelines
This article aims at discussing e-government website usability in relation to concerns about
digital inclusion. E-government web design should consider all aspects of usability, including
those that make it more accessible to all. Traditional concerns of social exclusion are being
superseded by fears that lack of digital competence and information literacy may result in dangerous
digital exclusion. Usability is considered as a way to address this exclusion and should
therefore incorporate inclusion and accessibility guidelines. This article makes an explicit link
between usability guidelines and digital inclusion and reports on a survey of local government
web presence in Portugal
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