Human operator response to error-likely situations in complex engineering systems

The causes of human error in complex systems are examined. First, a conceptual framework is provided in which two broad categories of error are discussed: errors of action, or slips, and errors of intention, or mistakes. Conditions in which slips and mistakes might be expected to occur are identified, based on existing theories of human error. Regarding the role of workload, it is hypothesized that workload may act as a catalyst for error. Two experiments are presented in which humans' response to error-likely situations were examined. Subjects controlled PLANT under a variety of conditions and periodically provided subjective ratings of mental effort. A complex pattern of results was obtained, which was not consistent with predictions. Generally, the results of this research indicate that: (1) humans respond to conditions in which errors might be expected by attempting to reduce the possibility of error, and (2) adaptation to conditions is a potent influence on human behavior in discretionary situations. Subjects' explanations for changes in effort ratings are also explored

A space transportation system operations model

Presented is a description of a computer program which permits assessment of the operational support requirements of space transportation systems functioning in both a ground- and space-based environment. The scenario depicted provides for the delivery of payloads from Earth to a space station and beyond using upper stages based at the station. Model results are scenario dependent and rely on the input definitions of delivery requirements, task times, and available resources. Output is in terms of flight rate capabilities, resource requirements, and facility utilization. A general program description, program listing, input requirements, and sample output are included

Rowan County - Folktales & Anedotes

Manuscript titled Over the Waves: Folktales and Anecdotes of Rowan County by Nancy Morris

Sodium azide inhibition of germination, growth and development in Dictyostelium discoideum.

Introduction: In the life cycle (Fig. 1) of members of the Acrasiomycetes, the cellular slime molds, growth is separate from differentiation allowing independent study of these stages. The earliest stage in the life cycle is the spore. Each spore may germinate releasing a single amoeboid cell, the myxamoeba. Myxamoebae feed and grow independently until there is a depletion of the food supply. At this time growth virtually stops and the myxamoebae cease to move independently, streaming instead toward aggregation centers. By the end of aggregation, two morphogenetically different cell types appear, pre-spore cells and pre-stalk cells, which coexist in a structure resembling a common garden slug, called the pseudoplasmodium. The pseudoplasmodium migrates in a direction influenced by various physical conditions such as heat, light, pH and ionic content of the medium. Culmination follows migration and begins when the pseudoplasmodium assumes a vertical position on the substratum. The individual cells then complete differentiation with the pre-spore cells being raised up off the agar surface on a vertical, cellular stalk. The result is a mature, stalked structure, the sorocarp, with spores at the apex

Deploying Jupyter Notebooks at scale on XSEDE resources for Science Gateways and workshops

Jupyter Notebooks have become a mainstream tool for interactive computing in every field of science. Jupyter Notebooks are suitable as companion applications for Science Gateways, providing more flexibility and post-processing capability to the users. Moreover they are often used in training events and workshops to provide immediate access to a pre-configured interactive computing environment. The Jupyter team released the JupyterHub web application to provide a platform where multiple users can login and access a Jupyter Notebook environment. When the number of users and memory requirements are low, it is easy to setup JupyterHub on a single server. However, setup becomes more complicated when we need to serve Jupyter Notebooks at scale to tens or hundreds of users. In this paper we will present three strategies for deploying JupyterHub at scale on XSEDE resources. All options share the deployment of JupyterHub on a Virtual Machine on XSEDE Jetstream. In the first scenario, JupyterHub connects to a supercomputer and launches a single node job on behalf of each user and proxies back the Notebook from the computing node back to the user's browser. In the second scenario, implemented in the context of a XSEDE consultation for the IRIS consortium for Seismology, we deploy Docker in Swarm mode to coordinate many XSEDE Jetstream virtual machines to provide Notebooks with persistent storage and quota. In the last scenario we install the Kubernetes containers orchestration framework on Jetstream to provide a fault-tolerant JupyterHub deployment with a distributed filesystem and capability to scale to thousands of users. In the conclusion section we provide a link to step-by-step tutorials complete with all the necessary commands and configuration files to replicate these deployments.Comment: 7 pages, 3 figures, PEARC '18: Practice and Experience in Advanced Research Computing, July 22--26, 2018, Pittsburgh, PA, US

Making Classrooms Culturally Sensitive

It is felt by many that as American schools and educators become more and more sensitive to the diversity of their community, their students can be guided to appreciate and respect these differences and to coexist peacefully. Various combinations of cultures such as African-Americans, Irish and German-Americans, Hispanics, Chinese-Americans to name a few, are learning how to work and live together while maintaining their own cultural heritage. The students of today who embrace their cultural heritage are trying to keep the values of their parents and grandparents, and still fit in with the students and cultures surrounding them. This dual search often confuses students and causes anxiety as they seek their own identity but attempt to live with other cultures. School systems and individual schools themselves can be extremely powerful agents in this process by providing insights to difficult cultural questions and issues facing students. Of course, a diverse school faculty can help by modeling behaviors that encourage classrooms to be settings where differences can be observed and studied. These same classrooms can help students begin to share, respect, and learn how to work with others. But it all starts by discovering and acknowledging individual and cultural differences and then by focusing on those things common to the group. To get a better picture classrooms that strive to be sensitive and aware four steps/stages for investigating cultural differences in classrooms have been developed and will now be discussed