4,930 research outputs found
Large-Scale Clustering of Cosmic Voids
We study the clustering of voids using -body simulations and simple
theoretical models. The excursion-set formalism describes fairly well the
abundance of voids identified with the watershed algorithm, although the void
formation threshold required is quite different from the spherical collapse
value. The void cross bias is measured and its large-scale value
is found to be consistent with the peak background split results. A simple
fitting formula for is found. We model the void auto-power
spectrum taking into account the void biasing and exclusion effect. A good fit
to the simulation data is obtained for voids with radii 30 Mpc/,
especially when the void biasing model is extended to 1-loop order. However,
the best-fit bias parameters do not agree well with the peak-background split
results. Being able to fit the void auto-power spectrum is particularly
important not only because it is the direct observable in galaxy surveys, but
also our method enables us to treat the bias parameters as nuisance parameters,
which are sensitive to the techniques used to identify voids.Comment: 20 pages, 14 figures, minor changes to match published versio
Sarcoidosis Presenting as Acute Respiratory Distress Syndrome.
Sarcoidosis is a multisystem granulomatous disease of unknown origin. It typically involves the lungs and mediastinal lymph nodes in a chronic fashion. However, acute syndrome has been reported possibly in response to systemic release of proinflammatory cytokines. Acute pulmonary manifestations, especially acute respiratory failure or acute respiratory distress syndrome, remain extremely uncommon in individuals without a prior diagnosis. We present the case of a 41-year-old African American female, who presented with ARDS. An extensive workup into the cause of her illness remained negative, and she subsequently succumbed to her illness. A diagnosis of sarcoidosis was made upon autopsy, after exclusion of other granulomatous illness. The case highlights the need to consider this uncommon diagnosis in patients with unexplained ARDS to guide therapy
Running the Domain: Truth, Rumours, and the Decision-Making of the Shimazu Warrior Family in 16th Century Japan
Using the Uwai Kakuken nikki, a diary kept by the middle-ranking warrior Uwai Kakuken from 1574 to 1586, this dissertation examines some fundamental factors that contributed to the political decision-making process of the Shimazu family in late sixteenth century Japan. In order to achieve this, this dissertation focuses on the Shimazu family’s communication system responsible for the gathering and delivery of information and military intelligence, and the management of rumours circulating within the entire Shimazu administration. Through the close reading and analysis of several key events in the Uwai Kakuken nikki, this dissertation argues that some of the primary factors affecting the decision-making process of the Shimazu family included the personal interests of the individual warriors involved in each instance and the perceived will of the deities as divined through lottery. Rather than acting in adherence to abstract notions of morality, loyalty, or truth, warriors often exploited the shortcomings of the communication system and the ambiguity of factual information in order to further their individual agendas. In the administration’s decision-making process, many warriors were interested in boosting their legitimacy, but at the same time, they were also concerned about protecting their siblings and children from harm. The argument pushes back against the language of loyalty appearing in and promoted by law codes and military tales of premodern Japan. Beyond the pursuit of one’s immediate interests, warriors also made decisions based heavily on their spiritual beliefs. Spiritual acts like the kuji played an important role in influencing the way the Shimazu administration made military decisions in this period. Through the exploration of the Uwai Kakuken nikki, the findings of this dissertation show that the samurai often prioritized their individual interests as a way to manage the volatile social and political situation of sixteenth century Japan. To that end, decisions were made with the aim of balancing the many variables and limited resources a warrior had access to at any given time, while also allowing a warrior to maximize his own interests.PHDHistoryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163042/1/vwch_1.pd
Measuring nonlocal Lagrangian peak bias
We investigate nonlocal Lagrangian bias contributions involving gradients of
the linear density field, for which we have predictions from the excursion set
peak formalism. We begin by writing down a bias expansion which includes all
the bias terms, including the nonlocal ones. Having checked that the model
furnishes a reasonable fit to the halo mass function, we develop a 1-point
cross-correlation technique to measure bias factors associated with
2-distributed quantities. We validate the method with numerical realizations of
peaks of Gaussian random fields before we apply it to N-body simulations. We
focus on the lowest (quadratic) order nonlocal contributions. We can reproduce
our measurement of \chi_{10} if we allow for an offset between the Lagrangian
halo center-of-mass and the peak position. The sign and magnitude of \chi_{10}
is consistent with Lagrangian haloes sitting near linear density maxima. The
resulting contribution to the halo bias can safely be ignored for M = 10^13
Msun/h, but could become relevant at larger halo masses. For the second
nonlocal bias \chi_{01} however, we measure a much larger magnitude than
predicted by our model. We speculate that some of this discrepancy might
originate from nonlocal Lagrangian contributions induced by nonspherical
collapse.Comment: (v2): presentation clarified. agreement with the simulation improved.
accepted for publication. 11 pages, 8 figure
Range-Free Localization with the Radical Line
Due to hardware and computational constraints, wireless sensor networks
(WSNs) normally do not take measurements of time-of-arrival or
time-difference-of-arrival for rangebased localization. Instead, WSNs in some
applications use rangefree localization for simple but less accurate
determination of sensor positions. A well-known algorithm for this purpose is
the centroid algorithm. This paper presents a range-free localization technique
based on the radical line of intersecting circles. This technique provides
greater accuracy than the centroid algorithm, at the expense of a slight
increase in computational load. Simulation results show that for the scenarios
studied, the radical line method can give an approximately 2 to 30% increase in
accuracy over the centroid algorithm, depending on whether or not the anchors
have identical ranges, and on the value of DOI.Comment: Proc. IEEE ICC'10, Cape Town, South Africa, May, 201
USING A K-NEAREST NEIGHBORS MACHINE LEARNING APPROACH TO DETECT CYBERATTACKS ON THE NAVY SMART GRID
In 2019, the Naval Facilities Engineering Command (NAVFAC) deployed the Navy smart grid across multiple bases in the United States. The smart grid can improve the reliability, availability, and efficiency of electricity supply. While this brings about immense benefit, placing the grid on a network connected to the internet increases the threat of cyberattacks aimed at intelligence collection, disruption, and destruction. In this thesis, we propose an Intrusion Detection System (IDS) for the NAVFAC smart grid. This IDS comprises a feature extractor, classifier, anomaly detector, and response manager. We use the K-Nearest Neighbors machine learning algorithm to show that various attacks (web attacks, FTP/SSH attacks, DOS, DDOS and port scanning) can be grouped into broader attack classes of Active, Denial, and Probe for appropriate response management. We also show that in order to reduce the load on the security operations center (SOC), the accuracy of the classifier can be maximized by optimizing the value of k, which is the number of data points nearest to the sample under consideration that decides the class assigned.http://archive.org/details/usingaknearestne1094566054Outstanding ThesisCommander, Republic of Singapore NavyApproved for public release. distribution is unlimite
The Beginning of the End of the Broad-Brush Approach? – A Case Comment of UQP v UQQ [2019] SGHCF 7 (April 2019). Singapore Law Watch Commentary (Issue 1 of Apr 2019)
The High Court in UQP v UQQ [2019] SGHCF 7 has created another exception to the broad-brush approach from ANJ v ANK [2015] 4 SLR 1043 for the division of matrimonial assets by resisting its application to this short dual-income marriage. This case comment argues that the broad-brush approach ought to have been applied to division of the matrimonial home (that is held in the Wife’s sole name) despite it being wholly financed by the wife and her father before and during the marriage. The author proposes that it is perhaps time to reconsider equality as the starting point to have a single test for the division of matrimonial assets
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