3,164 research outputs found
Measuring environmental perceptions and sense of place in Franklin County, Florida
Franklin County, Florida is widely perceived as one of the last unspoiled areas on
the Gulf Coast. This study examines the historical geography, economic activities and
socio-cultural aspects of the area which contribute to the construction of sense of place
values among residents and visitors. The commodification of nature emerged as a
consistent theme of this research from the timber and seafood industries to real estate
development and tourism. This study uses both qualitative and quantitative techniques
to analyze environmental perceptions and sense of place intensity. Results provided an
opportunity to compare the two methods and to identify key factors contributing to the
construction of sense of place. Informants perceived that the areas unique way of life
linked to the natural environment played an important role in sense of place and personal
identity construction.Department of GeographyThesis (M.S.
Bayesian inference for queueing networks and modeling of internet services
Modern Internet services, such as those at Google, Yahoo!, and Amazon, handle
billions of requests per day on clusters of thousands of computers. Because
these services operate under strict performance requirements, a statistical
understanding of their performance is of great practical interest. Such
services are modeled by networks of queues, where each queue models one of the
computers in the system. A key challenge is that the data are incomplete,
because recording detailed information about every request to a heavily used
system can require unacceptable overhead. In this paper we develop a Bayesian
perspective on queueing models in which the arrival and departure times that
are not observed are treated as latent variables. Underlying this viewpoint is
the observation that a queueing model defines a deterministic transformation
between the data and a set of independent variables called the service times.
With this viewpoint in hand, we sample from the posterior distribution over
missing data and model parameters using Markov chain Monte Carlo. We evaluate
our framework on data from a benchmark Web application. We also present a
simple technique for selection among nested queueing models. We are unaware of
any previous work that considers inference in networks of queues in the
presence of missing data.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS392 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Inference and Learning in Networks of Queues
Probabilistic models of the performance of computer systems are useful both for predicting system performance in new conditions, and for diagnosing past performance problems. The most popular performance models are networks of queues. However, no current methods exist for parameter estimation or inference in networks of queues with missing data. In this paper, we present a novel viewpoint that combines queueing networks and graphical models, allowing Markov chain Monte Carlo to be applied. We demonstrate the effectiveness of our sampler on real-world data from a benchmark Web application.
Probabilistic Inference in Queueing Networks
Although queueing models have long been used to model the performance of computer systems, they are out of favor with practitioners, because they have a reputation for requiring unrealistic distributional assumptions. In fact, these distributional assumptions are used mainly to facilitate analytic approximations such as asymptotics and large-deviations bounds. In this paper, we analyze queueing networks from the probabilistic modeling perspective, applying inference methods from graphical models that afford significantly more modeling flexibility. In particular, we present a Gibbs sampler and stochastic EM algorithm for networks of M/M/1 FIFO queues. As an application of this technique, we localize performance problems in distributed systems from incomplete system trace data. On both synthetic networks and an actual distributed Web application, the model accurately recovers the system’s service time using 1 % of the available trace data.
Lowest-Low Fertility in Japan: Consequences For A Once-Great Nation
Japan, once a great economic superpower, is currently one of a number of countries experiencing lowest-low fertility, having a total fertility rate of less than 1.5. This demographic figure exists alongside two decades of low economic growth, undermining confidence in national integrity and longevity. The association of low growth and lowest-low fertility has provoked a contest between two visions for national rejuvenation - one an old and increasingly discredited liberalism, and the second, a new demographic conservatism. Japan's debate is not new or unique. Questioning the methods for national replacement and the relationship between fertility and national integrity remains a crucial aspect of nationalism in a globalized world. In the Japanese context, the contest is between two visions for the nation - on the one hand, a cautious nationalism with attendant liberal proclivities; on the other a more conservative vision for the role of women in the family and civic duties. The election of the Democratic Party of Japan (DJP) in 2009 saw fertility issues prominent in the election campaign. Nonetheless, recapturing the lost economic greatness and the role of fertility in definitions of Japanese nationalism remain unresolved and controversial issues
A Study of the Effects of the Track Starter\u27s Time Intervals
[From the Introduction, Statement of the Problem] The purpose of this study was to investigate the effects of the track starter\u27s time interval on the performance of the track runner. It was also a purpose of the study to show the need for more competent starters and clinics for training these officials
The Relationship Between Stressor Rankings And Management Styles Of Nevada Elementary And Secondary Public School Principals (Leadership Style, Stress)
The purpose of this study was to determine what relationships existed between various stressor rankings selected from the Administrative Events Stress Inventory, and selected leadership styles as determined by the Leader Adaptability Style Inventory and exhibited by the elementary and secondary school administrators in the State of Nevada; The findings of the study were: (1) A majority of Nevada school principals were of the leadership style consisting of a High Task/High Relationship orientation. (2) There were no significant correlations between the four leadership styles as determined by the Leader Adaptability Style Inventory and selected job stressor events selected from the Administrative Events Stress Inventory. (3) A negative Pearson Product-Moment Correlation Coefficient was determined to exist between leadership styles involving Low Task orientation and job stressor events. (4) A positive Pearson Product-Moment Correlation Coefficient was determined to exist between the leadership styles involving a High Task orientation and job stressor events
Legislating the Tower of Babel: International Restrictions on Internet Content and the Marketplace of Ideas
The First Amendment to the U.S. Constitution protects the expression of diverse viewpoints in virtually any medium. Nevertheless, the modern novelty of borderless communication via the Internet strains our ideal of keeping government out of the business of regulating speech. This Note reveals the conflict between the First Amendment\u27s national protections and the Internet\u27s lack of national boundaries, while also arguing for international intervention for the protection of free speech. This Author articulates the real danger of watered-down speech unless both the FCC and the international community provide regulations and harmonized international standards for online content that reflect First Amendment protections
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