2,139 research outputs found
Building a quality culture in the Office of Space Flight: Approach, lessons learned and implications for the future
The purpose of this paper is to describe the approach and lessons learned by the Office of Space Flight (OSF), National Aeronautics and Space Administration (NASA), in its introduction of quality. In particular, the experience of OSF Headquarters is discussed as an example of an organization within NASA that is considering both the business and human elements of the change and the opportunities the quality focus presents to improve continuously. It is hoped that the insights shared will be of use to those embarking upon similar cultural changes. The paper is presented in the following parts: the leadership challenge; background; context of the approach to quality; initial steps; current initiatives; lessons learned; and implications for the future
SETTING PRIORITIES IN FOODBORNE PATHOGEN DATA: PUBLIC AND PRIVATE RESPONSE
Foodborne pathogens, foodborne illness, cost of illness, databases, Food Consumption/Nutrition/Food Safety,
From usability to secure computing and back again
Secure multi-party computation (MPC) allows multiple parties
to jointly compute the output of a function while preserving
the privacy of any individual party’s inputs to that function.
As MPC protocols transition from research prototypes to realworld
applications, the usability of MPC-enabled applications
is increasingly critical to their successful deployment and
widespread adoption. Our Web-MPC platform, designed with
a focus on usability, has been deployed for privacy-preserving
data aggregation initiatives with the City of Boston and the
Greater Boston Chamber of Commerce. After building and
deploying an initial version of the platform, we conducted a
heuristic evaluation to identify usability improvements and
implemented corresponding application enhancements. However,
it is difficult to gauge the effectiveness of these changes
within the context of real-world deployments using traditional
web analytics tools without compromising the security guarantees
of the platform. This work consists of two contributions
that address this challenge: (1) the Web-MPC platform has
been extended with the capability to collect web analytics
using existing MPC protocols, and (2) as a test of this feature
and a way to inform future work, this capability has been
leveraged to conduct a usability study comparing the two versions
ofWeb-MPC. While many efforts have focused on ways
to enhance the usability of privacy-preserving technologies,
this study serves as a model for using a privacy-preserving
data-driven approach to evaluate and enhance the usability of
privacy-preserving websites and applications deployed in realworld
scenarios. Data collected in this study yields insights
into the relationship between usability and security; these can
help inform future implementations of MPC solutions.Published versio
Room reflections and constancy in speech-like sounds: within-band effects
The experiment asks whether constancy in hearing precedes or follows grouping. Listeners heard speech-like
sounds comprising 8 auditory-filter shaped noise-bands that had temporal envelopes corresponding to those
arising in these filters when a speech message is played. The „context‟ words in the message were “next you‟ll
get _to click on”, into which a “sir” or “stir” test word was inserted. These test words were from an 11-step
continuum that was formed by amplitude modulation. Listeners identified the test words appropriately and quite
consistently, even though they had the „robotic‟ quality typical of this type of 8-band speech. The speech-like
effects of these sounds appears to be a consequence of auditory grouping. Constancy was assessed by comparing
the influence of room reflections on the test word across conditions where the context had either the same level
of reflections, or where it had a much lower level. Constancy effects were obtained with these 8-band sounds,
but only in „matched‟ conditions, where the room reflections were in the same bands in both the context and the
test word. This was not the case in a comparison „mismatched‟ condition, and here, no constancy effects were
found. It would appear that this type of constancy in hearing precedes the across-channel grouping whose
effects are so apparent in these sounds. This result is discussed in terms of the ubiquity of grouping across
different levels of representation
Does Order Matter? Investigating the Effect of Sequence on Glance Duration During On-Road Driving
Previous literature has shown that vehicle crash risks increases as drivers’ off-road glance duration increases. Many factors influence drivers’ glance duration such as individual differences, driving environment, or task characteristics. Theories and past studies suggest that glance duration increases as the task progresses, but the exact relationship between glance sequence and glance durations is not fully understood. The purpose of this study was to examine the effect of glance sequence on glance duration among drivers completing a visual-manual radio tuning task and an auditory-vocal based multi-modal navigation entry task. Eighty participants drove a vehicle on urban highways while completing radio tuning and navigation entry tasks. Forty participants drove under an experimental protocol that required three button presses followed by rotation of a tuning knob to complete the radio tuning task while the other forty participants completed the task with one less button press. Multiple statistical analyses were conducted to measure the effect of glance sequence on glance duration. Results showed that across both tasks and a variety of statistical tests, glance sequence had inconsistent effects on glance duration—the effects varied according to the number of glances, task type, and data set that was being evaluated. Results suggest that other aspects of the task as well as interface design effect glance duration and should be considered in the context of examining driver attention or lack thereof. All in all, interface design and task characteristics have a more influential impact on glance duration than glance sequence, suggesting that classical design considerations impacting driver attention, such as the size and location of buttons, remain fundamental in designing in-vehicle interfaces
User study to optimize a naturalistic voice navigation system
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 36).Advanced automotive technology such as adaptive cruise control and navigation systems are becoming ever more popular. With all of the technology to aid the driver, it is difficult to recognize when the technology used to inform the driver is more of a distraction than a benefit. Specifically, the user interaction associated with navigation systems has not been perfected. In response, the Computer Science and Artificial Intelligence Laboratory at MIT has created City Browser, an in-vehicle naturalistic navigation system that allows the user to search an online database for points on interest and to find directions. To gain feedback on the operation of the system in order to improve it for consumer use, a user study was conducted with over 90 participants. Each subject was also separated into different demographic groups as to quantify the difference of age and gender on system interaction. During the course of the experiment, three different forms of data collection were obtained: self report questionnaires, audio recordings, and physiology measurements such as heart rate, breathing rate, and skin conductance. The results indicate that users' feel the system is enjoyable, useful, and easy to learn. At the same time, users were also displeased with the voice of the system and felt that operating the system required a high level of concentration. The system had a response accuracy of 54.7% and had tendency to recognize the voice of 25-34 and 45-54 year old males better than other demographic group. The physiological measurements taken from the study were deemed to be inconclusive for determining the task difficulty and hence, more testing and analysis is needed. Overall, the City Browser system has proven to be practical in allowing users access to real time directions and points of interest in the greater Boston area. The results from this user study will allow the system to continually develop into a product for consumer use.by Shannon Colette Roberts.S.B
Type I Interferons Regulate Cytolytic Activity of Memory CD8+ T Cells in the Lung Airways during Respiratory Virus Challenge
SummaryMemory CD8+ T cells in the lung airways provide protection from secondary respiratory virus challenge by limiting early viral replication. Here, we demonstrate that although airway-resident memory CD8+ T cells were poorly cytolytic, memory CD8+ T cells recruited to the airways early during a recall response showed markedly enhanced cytolytic ability. This enhanced lytic activity did not require cognate antigen stimulation, but rather was dependent on STAT1 transcription factor signaling through the interferon-α receptor (Ifnar1), resulting in the antigen-independent expression of granzyme B protein in both murine and human virus-specific T cells. Signaling through Ifnar1 was required for the enhanced lytic activity and control of early viral replication by memory CD8+ T cells in the lung airways. These findings demonstrate that innate inflammatory signals act directly on memory T cells, enabling them to rapidly destroy infected host cells once they enter infected tissues
Resilience is Low among Both Military and Non-Military Populations with Post-Traumatic Stress Disorder
Post-traumatic stress disorder (PTSD) affects the lives of 12 million people in the United States. While commonly thought of in relation to military personnel and veterans, PTSD is also common among the general public. Resilience - the ability to cope with stressful events - is essential for recovering from PTSD. This data slice uses data from the National Wellbeing Survey to examine resilience among U.S. working-age adults with and without PTSD by their relationship to the military. Results show that those with PTSD have less resilience than those who have not experienced PTSD. In addition, those with military experience are more resilient than those without military experience
Seasonal range fidelity of a megaherbivore in response to environmental change
For large herbivores living in highly dynamic environments, maintaining range fidelity has the potential to facilitate the exploitation of predictable resources while minimising energy expenditure. We evaluate this expectation by examining how the seasonal range fidelity of African elephants (Loxodonta africana) in the Kruger National Park, South Africa is affected by spatiotemporal variation in environmental conditions (vegetation quality, temperature, rainfall, and fire). Eight-years of GPS collar data were used to analyse the similarity in seasonal utilisation distributions for thirteen family groups. Elephants exhibited remarkable consistency in their seasonal range fidelity across the study with rainfall emerging as a key driver of space-use. Within years, high range fidelity from summer to autumn and from autumn to winter was driven by increased rainfall and the retention of high-quality vegetation. Across years, sequential autumn seasons demonstrated the lowest levels of range fidelity due to inter-annual variability in the wet to dry season transition, resulting in unpredictable resource availability. Understanding seasonal space use is important for determining the effects of future variability in environmental conditions on elephant populations, particularly when it comes to management interventions. Indeed, over the coming decades climate change is predicted to drive greater variability in rainfall and elevated temperatures in African savanna ecosystems. The impacts of climate change also present particular challenges for elephants living in fragmented or human-transformed habitats where the opportunity for seasonal range shifts are greatly constrained
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