2,866 research outputs found
Approximate Bayesian Model Selection with the Deviance Statistic
Bayesian model selection poses two main challenges: the specification of
parameter priors for all models, and the computation of the resulting Bayes
factors between models. There is now a large literature on automatic and
objective parameter priors in the linear model. One important class are
-priors, which were recently extended from linear to generalized linear
models (GLMs). We show that the resulting Bayes factors can be approximated by
test-based Bayes factors (Johnson [Scand. J. Stat. 35 (2008) 354-368]) using
the deviance statistics of the models. To estimate the hyperparameter , we
propose empirical and fully Bayes approaches and link the former to minimum
Bayes factors and shrinkage estimates from the literature. Furthermore, we
describe how to approximate the corresponding posterior distribution of the
regression coefficients based on the standard GLM output. We illustrate the
approach with the development of a clinical prediction model for 30-day
survival in the GUSTO-I trial using logistic regression.Comment: Published at http://dx.doi.org/10.1214/14-STS510 in the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Recommended from our members
Shortest paths in orthogonal graphs
Orthogonal graphs were introduced as a simple but powerful tool for the description and analysis of a class of interconnection networks. Routing, and hence finding shortest paths between any two nodes of an orthogonal graph, becomes an important problem. It is shown in this paper that routing in this class of graphs reduces to a node covering problem in the bipartite coverage graph of the orthogonal graph. A minimum cover clearly leads to a shortest path. In general, the problem of finding the mínimum node cover in a bipartite graph is NP-complete. However, the bipartite coverage graphs corresponding to orthogonal graphs have a regular pattern of edges. This allows the development of a routing algorithm which results in a minimum cover. The procedure executes in polynomial time in the number of bit-nodes of the bipartite graph. It therefore results in a shortest path algorithm whose time complexity is quadratic in the logarithm of the number of nodes in the original orthogonal graph
Self, subjectivity, and impetus for Latino self-transformation in the writings of Kierkegaard, The
2010 Fall.Includes bibliographical references.The following thesis will explore the relationship between the conceptions of the self and subjectivity in writings of 19th century Danish philosopher Søren Kierkegaard and the contemporary problem of Latino male self-transformation. Kierkegaard's conception of the self will take Sickness Unto Death (1849) as the focal point, while Kierkegaard's conception of subjectivity will be explored in Concluding Unscientific Postscript (1846). First, I will discuss three aspects of Kierkegaard's dialectical self: the irresolute self, the resolute self, and the religious dependent self. Second, after these aspects of the self are discussed, I turn my attention to Kierkegaard's conception of subjectivity. The discussion on subjectivity will explore four perspectives of subjectivity: objective and subjective thinking, subjectivity and indirect communication, subjectivity as inwardness, existence, and passion, and lastly subjectivity and truth. Third, I discuss David T. Abalos' theory of transformation in The Latino Male: A Radical Redefinition (2002). My discussion of Abalos' theory of transformation will focus on the Three Acts of the Core Drama of Life in its application to Latino male self-transformation. My aim is to take Kierkegaard's remarks on the self and subjectivity and apply them to Abalos' theory of Latino male self-transformation. I attempt to demonstrate that Kierkegaard's remarks on these issues can inform and aid in the conversation of the contemporary problem of Latino male self-transformation. Thus, I argue that Kierkegaard's remarks on the self and subjectivity are not only invaluable to this contemporary problem, but can provide impetus for Latino male self-transformation
Biology of Seed Vigor in the Light of -omics Tools
Seed vigor is a major agronomic trait measurable by seed longevity in storage, germination capacity, and seedling growth in the field. Seed vigor has potential to significantly elevate crop resilience to biotic and abiotic stresses. That is important for crop yields enhancement and other enterprises that involve seeds like plant breeding, research and education, germplasm conservation and the seed trade. With the availability of high precision -omics tools for biological research, lots of investigations are undertaken globally to answer the physiological questions underlying seed germination and invigoration. The increasing -omics datasets constitute important resources for the delivery of new seed vigor markers and advancing new seed vigor manipulation opportunities. There is need to regularly update the knowledge generated from these investigations for the scientific improvement of seed vigor. Thus, this chapter highlights the biological backgrounds involved in the development of seed vigor traits in the light of modern -omics tools. The chapter is sectioned into; 1. Attributes of seed vigor and the –omics sciences; 2. State of -omics-based knowledge on underlying mechanisms of seed vigor; 3. Future perspectives of -omics application to genetic engineering of seed vigor with an insight to the latest technique of genome editing, the CRISPR-Cas9 technology
Participation And performance In 8.02x Electricity And Magnetism: The First Physics MOOC From MITx
Massive Open Online Courses are an exciting new avenue for instruction and
research, yet they are full of unknowns. In the Spring of 2013, MITx released
its first introductory physics MOOC through the edX platform, generating a
total enrollment of 43,000 students from around the world. We describe the
population of participants in terms of their age, gender, level of education,
and country of origin, highlighting both the diversity of 8.02x enrollees as
well as gender gap and retention. Using three midterm exams and the final as
waypoints, we highlight performance by different demographic subpopulations and
their retention rates. Our work is generally aimed at making a bridge between
available MOOC data and topics associated with the Physics Education Research
community.Comment: 4 pages, 5 figures, Accepted for publication in the Physics Education
Research Conference Proceedings, Portland OR 201
Recommended from our members
Superior Semicircular Canal Dehiscence in a Patient with Ehlers-Danlos Syndrome: A Case Report.
Superior semicircular canal dehiscence (SSCD) is a bony defect in the middle cranial fossa floor that results in an abnormal connection between the inner ear and cranial vault. Although the etiology of SSCD remains unclear, an inappropriately thin or fragile temporal bone likely predisposes an individual towards developing SSCD. Ehlers-Danlos syndrome (EDS) constitutes a group of genetic connective tissue disorders caused by a defect in the production, processing, or structure of collagen, or its associated proteins. The possible association between SSCD and EDS has not been previously described in the literature. We herein report a case of a 50-year-old female with EDS-hypermobility type who presented with a 15-year history of migraines, vertigo, and tinnitus. The patient was subsequently diagnosed with bilateral SSCD and underwent a right middle fossa (pre-auricular infratemporal) craniotomy for SSCD repair. She reported significant improvement in her auditory and vestibular symptoms, with the exception of continued mild dizziness and disequilibrium at the 3-month follow-up. Due to the rare reports of auditory symptoms in EDS, this case study highlights the importance of considering an otological consultation for auditory manifestations in a patient with EDS and illustrates a potential association between EDS and SSCD
ADESS: A Proof-of-Work Protocol to Deter Double-Spend Attacks
A principal vulnerability of a proof-of-work ("PoW") blockchain is that an
attacker can re-write the history of transactions by forking a previously
published block and build a new chain segment containing a different sequence
of transactions. If the attacker's chain has the most cumulative mining puzzle
difficulty, nodes will recognize it as canonical. We propose a modification to
PoW protocols, called ADESS, that contains two novel features. The first
modification enables a node to identify the attacker chain by comparing the
temporal sequence of blocks on competing chains. The second modification
penalizes the attacker by requiring it to apply exponentially increasing
hashrate in order to make its chain canonical. We demonstrate two things; (i)
the expected cost of carrying out a double-spend attack is weakly higher under
ADESS compared to the current PoW protocols and (ii) for any value of
transaction, there is a penalty setting in ADESS that renders the expected
profit of a double-spend attack negative.Comment: 33 pages. Accepted at Future of Information and Communications
Conference 202
Application of Lean Manufacturing Principles to increase machine availability in Peruvian SMEs in the textile sector
Based on figures in the textile industry over the past years, it can be assumed currently that this industry is one of the most important markets in different countries because of high consumption. Due to economic value and the increasing work activities in the textile sector is related to the last trends in fashion. However, there are still challenges to overcome for instance: low availability of machines or poor human resources management generate economic and productive impacts. Within this context, it arises the need to propose an integrated model combining Total Productive Maintenance (TPM) and Lean Leadership which supports and creates a synergy between maintenance management and human resources; by using tools such as the orders and maintenance plan, system simulation in two comparative scenarios, a continuous system assessment combined with 5S methodology, and providing education and training in good practices in lean Leadership. Thereafter, the model was implemented, the availability indicator was calculated to attack the main problem and as result, it had an increase of 10.56%, this increase supports optimally and validates the proposal of the present study
Stitched transmission lines for wearable RF devices
With the rapid growth and use of wearable devices over the last decade, the advantages of using portable wearable devices are now been utilised for day to day activities. These wearable devices are designed to be flexible, low profile, light-weight and smoothly integrated into daily life. Wearable transmission lines are required to transport RF signals between various pieces of wearable communication equipment and to connect fabric based antennas to transmitters and receivers; the stitched transmission line is one of the hardware solutions developed to enhance the connectivity between these wearable devices. Textile manufacturing techniques that employ the use of sewing machines alongside conductive textile materials can be used to fabricate the stitched transmission line.
In this thesis the feasibility of using a sewing machine in fabrication of a novel stitched transmission line for wearable devices using the idea of a braided coaxial cable have been examined. The sewing machine used is capable of a zig-zag stitch with approximate width and length within the range of 0-6 mm and 0-4mm respectively. The inner conductor and the tubular insulated layer of the stitched transmission lines were selected as RG 174, while the stitched shields were made up of copper wires and conductive threads from Light Stiches®. For shielding purpose, the structure is stitched onto a denim material with a conductive thread with the aid of a novel manufacturing technique using a standard hardware. The Scattering Parameters of the stitched transmission line were investigated with three different stitch angles 85°,65° and 31° through simulation and experiments, with the results demonstrating that the stitched transmission line can work usefully and consistently from 0.04 4. The extracted Scattering parameters indicated a decrease in DC loss with increased stitch angle and an increase in radiation loses, which tends to increase with increase in frequency. The proposed stitched transmission line makes a viable transmission line but a short stitch length is associated with larger losses through resistance. The DC losses observed are mainly influenced by the resistance of the conductive threads at lower frequencies while the radiation losses are influenced by the wider apertures related to the stitch angles and increase in frequency along the line.
The performances of the stitched transmission line with different stitch patterns, when subjected to washing cycles and when bent through curved angles 90° and 180° were also investigated and results presented.
ii
Also, the sensitivity of the design to manufacturing tolerances was also considered. First the behaviour of the stitched transmission line with two different substrates Denim and Felt were investigated with the results indicating an insignificant increase in losses with the Denim material. Secondly, the sensitivity of the design with variations in cross section dimensions was investigated using numerical modelling techniques and the results showed that the impedance of the stitched transmission line increases when the cross sectional dimensions are decreased by 0.40 and decreases when the cross sectional dimensions are increased by 0.40. Equally, repeatability of the stitched transmission line with three different stitch angles 85°,65° and 31° were carried out. The results were seen to be consistent up to 2.5, with slight deviations above that, which are mainly as a result of multiple reflections along the line resulting in loss ripples.
The DC resistance of the stitched transmission line with three different stitch angles 85°,65° and 31° corresponding to the number of stitches 60,90 and 162 were computed and a mathematical relationship was derived for computing the DC resistance of the stitch transmission line for any given number of stitches. The DC resistance computed results of 25.6Ω,17.3Ω and 13.1Ω, for 31°,65° and 85° stitch angles, indicated an increase in DC resistance of the stitch with decrease in stitch angle which gives rise to an increase in number of stitches. The transfer impedance of the stitched transmission line was also computed at low frequency (<1) to be =(0.24+1.09)Ω, with the result showing the effectiveness of the shield of the stitched transmission line at low frequency (<1
- …