36 research outputs found
An exploratory study of mood states and transient emotion in amateur dressage riders
No full textThe purpose of this study was to explore the horse-rider relationship through the effect of a rider’s mood on the horse’s behavior in practice and competition. A total of 18 Female amateur dressage riders participated in this study. The participants completed five surveys and two observations. Surveys included a demographic survey, Rotter’s I-E Scale, Orientation to Life Questionnaire, and the Profile of Mood States (POMS). Observations took place at a scheduled practice and during one competition per participant. The POMS results showed increased mood disturbance from the riders (N=16, M= -9.94), p= 0.03 between practice and competition. Observation data revealed no significance in horse conflict behavior between practice and competition (M= -1.18) p= 0.95. The differences between rider TMD and horse conflict behavior pre- and post-competition, the results demonstrated a strong, positive, and significant correlation (r=0.868), p=0.000. These results are preliminary, but highlight a potential moderator of the horse-rider relationship
Overview of studies discussing specific factors affecting EMPs’ experiences (n = 23): author, year, country of publication, sample, aim, and synthesis of specific factors.
No full text<p><sup>a</sup>UK: United-Kingdom.</p><p><sup>b</sup>USA: United-States of America.</p><p><sup>c</sup>FG: Focus group interviews.</p><p><sup>d</sup>EMPs: Ethnic minority patients.</p><p>Overview of studies discussing specific factors affecting EMPs’ experiences (n = 23): author, year, country of publication, sample, aim, and synthesis of specific factors.</p
Cognitive and affective processes in children’s third-party punishment
No full textThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Nigel Groome Studentship and Santander Research Scholarship (both awarded to Rhea L. Arini) and internal research funding from the Faculty of Social Sciences, Universidad de los Andes, Colombia (awarded to Gordon P. D. Ingram)
Studies of early intense cratering and possible saturation effects
No full textCrater counts on Rhea were completed, to be compared and combined with independent counts by Steve Squyres; the material is now being integrated into a study of cratering on Rhea and other Saturn satellites by Squyres, Lissauer, and Hartmann. Special attention is being paid to lighting and other effects on the apparent changes in crater density from one region to another. An earlier proposal by the author on crater density was further tested. Brief preliminary results are given
Osteological stops.
No full text<p>The posterior cervicals of camel Camelus dromedarius (A) show pronounced depressions (see arrow) where the postzygapophyses make contact just posterior to the associated prezygapophyses with which they articulate. At the limit of travel in dorsiflexion the zygapophyses remain in overlap (contra <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078572#pone.0078572-Sereno2" target="_blank">[80]</a>) and compression forces can be transmitted through the zygapophyses as the neck becomes effectively rigid and stable at the extremes of dorsiflexion. Pronounced osteological stops are also exhibited in many birds, such as the Greater Rhea Rhea americana (B, see arrows). Photographs by the author; rhea specimen at the Zoology Museum, University of Cambridge, access courtesy Matthew Lowe, and the camel vertebrae are at the Condon Museum, University of Oregon.</p
Surrogate modeling for large-scale black-box systems
No full textThesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 105-110).This research introduces a systematic method to reduce the complexity of large-scale blackbox systems for which the governing equations are unavailable. For such systems, surrogate models are critical for many applications, such as Monte Carlo simulations; however, existing surrogate modeling methods often are not applicable, particularly when the dimension of the input space is very high. In this research, we develop a systematic approach to represent the high-dimensional input space of a large-scale system by a smaller set of inputs. This collection of representatives is called a multi-agent collective, forming a surrogate model with which an inexpensive computation replaces the original complex task. The mathematical criteria used to derive the collective aim to avoid overlapping of characteristics between representatives, in order to achieve an effective surrogate model and avoid redundancies. The surrogate modeling method is demonstrated on a light inventory that contains light data corresponding to 82 aircraft types. Ten aircraft types are selected by the method to represent the full light inventory for the computation of fuel burn estimates, yielding an error between outputs from the surrogate and full models of just 2.08%. The ten representative aircraft types are selected by first aggregating similar aircraft types together into agents, and then selecting a representative aircraft type for each agent. In assessing the similarity between aircraft types, the characteristic of each aircraft type is determined from available light data instead of solving the fuel burn computation model, which makes the assessment procedure inexpensive.(cont.) Aggregation criteria are specified to quantify the similarity between aircraft types and a stringency, which controls the tradeoff between the two competing objectives in the modeling -- the number of representatives and the estimation error. The surrogate modeling results are compared to a model obtained via manual aggregation; that is, the aggregation of aircraft types is done based on engineering judgment. The surrogate model derived using the systematic approach yields fewer representatives in the collective, yielding a surrogate model with lower computational cost, while achieving better accuracy. Further, the systematic approach eliminates the subjectivity that is inherent in the manual aggregation method. The surrogate model is also applied to other light inventories, yielding errors of similar magnitude to the case when the reference light inventory is considered.by Rhea Patricia Liem.S.M
System level assessment of uncertainty in aviation environmental policy impact analysis
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.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. 83-93).This thesis demonstrates the assessment of uncertainty of a simulation model at the system level, which takes into account the interaction between the modules that comprise the system. Results from this system level assessment process aid policy-makers by identifying the key drivers of uncertainty in model outputs, among the input factors of the various modules that comprise the system. This knowledge can help direct resource allocation for research to reduce the uncertainty in policy outputs. The assessment results can also identify input factors that, when treated as deterministic variables, will not significantly affect the output variability. The system level assessment process is demonstrated on a model that estimates the air quality impacts of aviation. The model comprises two modules: the Aviation Environmental Design Tool (AEDT), which simulates aircraft operations to estimate performance and emissions inventories, and the Aviation environmental Portfolio Management Tool (APMT)- Impacts Air Quality module, which estimates the health and welfare impacts associated with aviation emissions. Global sensitivity analysis is employed to quantify the contribution of uncertainty in each input factor to the variability of system outputs, which here are adult mortality rates and total health cost. The assessment results show that none of the input factors of AEDT contribute significantly to the variability of system outputs. Therefore, if uncertainty reduction in the estimation of adult mortality and total health cost is desired, future research efforts should be directed towards gaining more knowledge on the input factors of the APMT-Impacts Air Quality module. This thesis also demonstrates the application of system level assessment in policy impact analysis, where policy impact is defined as the incremental change between baseline and policy outputs. In such an analysis, it is important to ensure that the uncertainty in policy impacts only accounts for the uncertainty corresponding to the difference between baseline and policy scenarios. Some input factors have a common source of uncertainty between scenarios, in which case the same representation of uncertainty must be used. Other input factors, on the other hand, are assumed to have independent variability between the different scenarios, and therefore need to have independent representation of uncertainty. This thesis demonstrates uncertainty assessment of a technology infusion policy analysis.by Rhea Patricia Liem.S.M
Weather-aware aircraft arrival characterization at terminal maneuvering area with data-driven methodologies
No full textAir traffic management (ATM) attempts to assist aircraft’s approach and landing procedures with a safety-first operation. It can be challenging to evaluate aviation economics, environmental issues, and safety operations all at once while making decisions inside the terminal maneuvering area (TMA). A comprehensive arrival plan that considers weather factors and aircraft trajectory configuration is essential to increase the job efficiency of air traffic controllers and alleviate the negative environmental impact. Current state-of-the-art solutions do not fully consider unfavorable weather circumstances and unusual aircraft paths in arrival scheduling, arrival airborne congestion, and arrival time prediction. This thesis proposes a framework for the aircraft trajectory aspect to extract features from data and predict arrival transit time, with consideration of adverse weather and non-standard flight trajectory operations. The developed procedures can reveal more air-traffic information and patterns from data, which can be used to predict arrival transit time in various situations better. The spatio-temporal pattern identification for aircraft congestion and arrival transit time within the Hong Kong International Airport TMA was presented in this thesis. To include weather factor, the hourly recorded weather radar images were also included in the analysis. To investigate weather impact, the author proposed a scheme to quantify the weather impact on airport arrival on-time performance, by using a growth function to represent the performance deterioration with increasingly more adverse weather conditions. The model parameters and hyperparameters were derived based on actual data via a Bayesian approach. The developed scheme could also quantify the impact of dangerous weather phenomena, which were often excluded in existing aviation weather impact studies. Results exhibited the generality and versatility of the developed weather impact quantification model, which could also be used to compare the aviation weather impact at different airports. The updateability of the Bayesian approach also allows us to consider the future climate change impact on arrivals. Lastly, the author developed a model architecture to predict arrival transit time by considering inputs pertaining to three important aspects in air traffic operations, namely aircraft, airport, and weather. The results indicated that the developed model structure could reduce the prediction errors by 5.63% when all weather conditions were considered and 8.45% under extreme weather scenarios. The arrival transit time prediction was demonstrated with several metrics to represent weather conditions. In particular, two metrics were introduced in this work that not only contained weather information, but also its interaction with airport traffic and individual flight time. These metrics were shown to yield better arrival transit time prediction accuracy than other weather metrics used in the study.</p
Flood depth and channel migration zone maps, Benton, Marion, Morrow, and Washington counties, Oregon
No full textReport -- Appendix A. Benton County -- Appendix A. Marion County -- Appendix A. Morrow County -- Appendix A. Washington County -- Alsea River CMZ summary -- Beaver Creek CMZ summary -- Beaverton Creek CMZ summary -- Dairy Creek CMZ summary -- East Fork Dairy Creek CMZ summary -- Fanno Creek CMZ summary -- Gales Creek CMZ summary -- Hinton Creek CMZ summary -- Marys River CMZ summary -- McKay Creek CMZ summary -- North Fork Alsea River CMZ summary -- Pudding River CMZ summary -- Rhea Creek CMZ summary -- Rock Creek CMZ summary -- Santiam and North Santiam River CMZ summary -- Tualatin River CMZ summary -- Tumtum River CMZ summary -- West Fork Dairy Creek CMZ summary -- Willow Creek CMZ summary.by Christina A. Appleby, Matt C. Williams, Lowell H. Anthony, and Ian P. Madin ."This report describes the methods and results of flood depth and channel migration zone mapping for Benton, Marion, Morrow, and Washington Counties, Oregon. This information can help communities plan and prepare for natural disasters"--Page ii.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Includes bibliographical references.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Autonomic management in a distributed storage system
No full textThis thesis investigates the application of autonomic management to a distributed storage
system. Effects on performance and resource consumption were measured in experiments,
which were carried out in a local area test-bed. The experiments were conducted with
components of one specific distributed storage system, but seek to be applicable to a wide range of such systems, in particular those exposed to varying conditions.
The perceived characteristics of distributed storage systems depend on their configuration
parameters and on various dynamic conditions. For a given set of conditions, one specific configuration may be better than another with respect to measures such as resource
consumption and performance. Here, configuration parameter values were set dynamically
and the results compared with a static configuration. It was hypothesised that under non-changing conditions this would allow the system to converge on a configuration that was
more suitable than any that could be set a priori. Furthermore, the system could react to
a change in conditions by adopting a more appropriate configuration. Autonomic management was applied to the peer-to-peer (P2P) and data retrieval components of ASA, a
distributed storage system. The effects were measured experimentally for various workload and churn patterns. The management policies and mechanisms were implemented
using a generic autonomic management framework developed during this work.
The motivation for both groups of experiments was to test management policies with the objective to avoid unsatisfactory situations with respect to resource consumption and performance. Such unsatisfactory situations occur when either the P2P layer or the data retrieval mechanism is configured statically. In a statically configured P2P system two unsatisfactory situations can be identified. The first arises when the frequency with which P2P node states are verified is low and membership churn is high. The P2P node state becomes inaccurate due to a high membership churn, leading to errors during the routing process and a reduction in performance. In this situation it is desirable to increase the frequency to increase P2P state accuracy. The converse situation arises when the frequency is high and churn is low. In this situation network resources are used unnecessarily, which may also reduce performance, making it desirable to decrease the frequency.
In ASA’s data retrieval mechanism similar unsatisfactory situations can be identified with respect to the degree of concurrency (DOC). The DOC controls the eagerness with which multiple redundant replicas are retrieved. An unsatisfactory situation arises when the DOC is low and there is a large variation in the times taken to retrieve replicas. In this situation it is desirable to increase the DOC, because by retrieving more replicas in parallel a
result can be returned to the user sooner. The converse situation arises when the DOC is
high, there is little variation in retrieval time and there is a network bottleneck close to the requesting client. In this situation it is desirable to decrease the DOC, since the low variation removes any benefit in parallel retrieval, and the bottleneck means that decreasing parallelism reduces both bandwidth consumption and elapsed time for the user.
The experimental evaluations of autonomic management show promising results, and suggest several future research topics. These include optimisations of the managed mechanisms, alternative management policies, different evaluation methods, and the application of developed management mechanisms to other facets of a distributed storage system. The findings of this thesis could be exploited in building other distributed storage systems that focus on harnessing storage on user workstations, since these are particularly likely to be exposed to varying, unpredictable conditions
