Heterogeneity aware fault tolerance for extreme scale computing

Upcoming Extreme Scale, or Exascale, Computing Systems are expected to deliver a peak performance of at least 10^18 floating point operations per second (FLOPS), primarily through significant expansion in scale. A major concern for such large scale systems, however, is how to deal with failures in the system. This is because the impact of failures on system efficiency, while utilizing existing fault tolerance techniques, generally also increases with scale. Hence, current research effort in this area has been directed at optimizing various aspects of fault tolerance techniques to reduce their overhead at scale. One characteristic that has been overlooked so far, however, is heterogeneity, specifically in the rate at which individual components of the underlying system fail, and in the execution profile of a parallel application running on such a system. In this thesis, we investigate the implications of such types of heterogeneity for fault tolerance in large scale high performance computing (HPC) systems. To that end, we 1) study how knowledge of heterogeneity in system failure likelihoods can be utilized to make current fault tolerance schemes more efficient, 2) assess the feasibility of utilizing application imbalance for improved fault tolerance at scale, and 3) propose and evaluate changes to system level resource managers in order to achieve reliable job placement over resources with unequal failure likelihoods. The results in this thesis, taken together, demonstrate that heterogeneity in failure likelihoods significantly changes the landscape of fault tolerance for large scale HPC systems

Vocabulary acquisition through extensive reading of unsimplified English material in a Saudi Arabian tertiary context

A thesis submitted to the University of Bedfordshire in fulfilment of the requirements for the degree of Doctor of PhilosophyA number of studies seem to indicate that Extensive Reading (ER) enhances language proficiency in general and vocabulary knowledge in particular. However none of those surveyed focused on poorly motivated lower level language learners in a normal course of study that incorporated ER of unsimplified material, and few addressed partial vocabulary gain and the other factors that could have affected this. In this study the participants were young adult male Saudi Arabians, who were elementary English language learners and who were not used to reading for pleasure even in Arabic. Tests were used to gauge their partial vocabulary acquisition when they engaged in ER involving an open choice of simplified and unsimplified English material during a regular English preparatory course of just one semester. If ER could be linked to improved vocabulary acquisition in such difficult but natural conditions, the case for ER‘s wider implementation could be strengthened. The study also used diaries, surveys and interviews to delve into the reading habits, academic background and cultural context that could also explain any observed vocabulary gain. The results showed there were few statistically significant partial vocabulary gains after the ER programme, and although the experimental cohort that received the ER programme showed greater gains than the control in most of these cases, the difference was not large in terms of the absolute number of words. The diaries, surveys and interviews gave a rich profile of the participants with a level of detail that surpassed that of any other surveyed study, offering several possible reasons for their modest vocabulary gains and yielding unanticipated findings, such as an exposition of their motivations for academic study. It is concluded that a greater awareness of the learners‘ context is essential when applying ER, which in this particular context leads to the view that pure ER may not be suitable for vocabulary learning, and instead a significantly modified version could be more appropriate. These modifications include selecting appropriate books for the students and adding explicit vocabulary learning activities, and they even include linking the reading to the students‘ final grade. Further research is needed to gauge the effectiveness of such modifications, while a more inductive approach is also important when investigating ER and vocabulary acquisition to give the opportunity for unforeseen results to emerge

Automatic Understanding of Image and Video Advertisements

There is more to images than their objective physical content: for example, advertisements are created to persuade a viewer to take a certain action. We propose the novel problem of automatic advertisement understanding. To enable research on this problem, we create two datasets: an image dataset of 64,832 image ads, and a video dataset of 3,477 ads. Our data contains rich annotations encompassing the topic and sentiment of the ads, questions and answers describing what actions the viewer is prompted to take and the reasoning that the ad presents to persuade the viewer ("What should I do according to this ad, and why should I do it?"), and symbolic references ads make (e.g. a dove symbolizes peace). We also analyze the most common persuasive strategies ads use, and the capabilities that computer vision systems should have to understand these strategies. We present baseline classification results for several prediction tasks, including automatically answering questions about the messages of the ads.Comment: To appear in CVPR 2017; data available on http://cs.pitt.edu/~kovashka/ad

Educational Motives and Perceived Educational Consequences as Predictors of Facebook Usage

This study proposes a model and validates it with the help of uses and gratifications theory, displacement theory and the individual differences theory. The tenets of the proposed model are: the associations of the educational motives with Facebook use; the association of perceived consequences resulting from Facebook use with the Facebook use; the interactional effect of the weekly time patterns and gender for Facebook use; the interactional effect of the daily and weekly time patterns for the educational motives for Facebook use; and the interactional effect of the daily and weekly time patterns for the perceived consequences resulting from Facebook use among university students in Lahore. By using convenience sampling technique, students are selected from the population of educational institutions in Lahore. The variance explained in the dependent variable of motives for Facebook usage and the perceived consequences is 22.9%. Both variables of educational motives (β = .402) and the perceived consequences (β = .200) have made significant contribution to the prediction of Facebook usage but the former has made the unique one. Male students are using Facebook more than the female students (η2 = .01). The interaction effect of daily and weekly time patterns have small effects on educational motives (η2 = .038) and the perceived consequences (η2 = .032). Facebook is found empowering the students for the educational motives, however university students perceive that Facebook use has consequences when they use it for more than two hours in different parts of the day

Social Media Usage Patterns Among University Students In Urban Lahore

Social media have transformed the communication patterns on a wider scale at the dawn of this century at an increasing speed. There is a need to measure these patterns on regular basis to research the shift in cultural transformation. The current study aims to find the overall social media usage patterns, the selection of media for using Facebook, use of Facebook to communicate with social relations and the mass media as reasons for Facebook use among university students. By using purposive sampling method the students were selected from two educational institutes in Lahore (N=500). The study had used quantitative approach of cross-sectional survey. All the university students were found to be using Facebook but majority was also using WhatsApp and YouTube. Smart phone was found to be prominent medium for Facebook use. Majority of university students were using Facebook for the motive of communicating with friends rather than communicating with the family

Understanding, Categorizing and Predicting Semantic Image-Text Relations

Two modalities are often used to convey information in a complementary and beneficial manner, e.g., in online news, videos, educational resources, or scientific publications. The automatic understanding of semantic correlations between text and associated images as well as their interplay has a great potential for enhanced multimodal web search and recommender systems. However, automatic understanding of multimodal information is still an unsolved research problem. Recent approaches such as image captioning focus on precisely describing visual content and translating it to text, but typically address neither semantic interpretations nor the specific role or purpose of an image-text constellation. In this paper, we go beyond previous work and investigate, inspired by research in visual communication, useful semantic image-text relations for multimodal information retrieval. We derive a categorization of eight semantic image-text classes (e.g., "illustration" or "anchorage") and show how they can systematically be characterized by a set of three metrics: cross-modal mutual information, semantic correlation, and the status relation of image and text. Furthermore, we present a deep learning system to predict these classes by utilizing multimodal embeddings. To obtain a sufficiently large amount of training data, we have automatically collected and augmented data from a variety of data sets and web resources, which enables future research on this topic. Experimental results on a demanding test set demonstrate the feasibility of the approach.Comment: 8 pages, 8 Figures, 5 table

Diversifying with few regrets, but too few to mention

Representative data provide users with a concise overview of their potentially large query results. Recently, diversity maximization has been adopted as one technique to generate representative data with high coverage and low redundancy. Orthogonally, regret minimization has emerged as another technique to generate representative data with high utility that satisfy the user's preference. In reality, however, users typically have some pre-specified preferences over some dimensions of the data, while expecting good coverage over the other dimensions. Motivated by that need, in this work we propose a novel scheme called ReDi, which aims to generate representative data that balance the tradeoff between regret minimization and diversity maximization. ReDi is based on a hybrid objective function that combines both regret and diversity. Additionally, it employs several algorithms that are designed to maximize that objective function. We perform extensive experimental evaluation to measure the tradeoff between the effectiveness and efficiency provided by the different ReDi algorithms

Label-free proteomic analysis reveals large dynamic changes to the cellular proteome upon expression of the miRNA-23a-27a-24-2 microRNA cluster

In deciphering the regulatory networks of gene expression controlled by the small non-coding RNAs known as microRNAs (miRNAs), a major challenge has been with the identification of the true mRNA targets by these RNAs within the context of the enormous numbers of predicted targets for each of these small RNAs. To facilitate the system wide identification of miRNA targets a variety of system wide methods, such as proteomics, have been implemented. Here we describe the utilization of quantitative label-free proteomics and bioinformatics to identify the most significant changes to the proteome upon expression of the miR-23a-27a-24-2 miRNA cluster. In light of recent work leading to the hypothesis that only the most pronounced regulatory events by miRNAs may be physiologically relevant, our data reveals that label-free analysis circumvents the limitations of proteomic labeling techniques that limit the maximum differences that can be quantified. The result of our analysis identifies a series of novel candidate targets that are reduced in abundance by more than an order of magnitude upon the expression of the miR-23a-27a-24-2 cluster.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Scientific basis for use of Pyrus pashia Buch.-Ham. ex D. Don. fruit in gastrointestinal, respiratory and cardiovascular ailments.

Pyrus pashia Buch.-Ham. ex D. Don. has been used conventionally by many communities in the Himalayan region for the management of gastrointestinal, respiratory, and vascular complications. Set against this background, this study was carried out to justify the scientific basis to validate folkloric uses of fruits of Pyrus pashia Buch.-Ham. ex D. Don. (Pp.Cr) in traditional systems of medicine.The crude ethanol extract of fruits of Pyrus pashia Buch.-Ham. ex D. Don. (Pp.Cr) was tested in vitro on isolated rabbit jejunum, tracheal, and aorta preparations. The responses of tissues were recorded using isotonic transducers coupled with a PowerLab data acquisition system.The Pp.Cr on application (0.01-5.0 mg/ml) to isolated rabbit jejunum preparation exhibited relaxation through decrease in magnitude and frequency of spontaneous contractions. The Pp.Cr also exerted a relaxant (0.01-5.0 mg/ml) effect on K+ (80 mM) induced contractions in isolated rabbit jejunum preparations and caused shifting of the Ca2+ curves (1.0-3.0 mg/ml) toward right in a manner similar to that of verapamil (3 μM), possibly suggesting presence of Ca2+ channel blocking activity. Subsequently, Pp.Cr in a concentration-dependent fashion (0.01-10.0 mg/ml) caused relaxation of CCh (1 μM) and K+ (80 mM) induced contractions in isolated rabbit tracheal preparations in a manner comparable to that of dicyclomine, suggesting that the observed relaxant effect is likely to be mediated through antimuscarinic and/or Ca2+ channel blocking activities. Moreover, when evaluated against isolated rabbit aortic preparations, the Pp.Cr in concentrations up to 10 mg/ml exhibited a contractile response that was found to be abolished subsequent to pretreatment of isolated tissue preparation with cyproheptadine (1 μM), phentolamine (1 μM), and losartan (1 μM), suggesting that Pp.Cr may have some α-adrenergic, muscarinic, serotonergic, and angiotensin II activities.The aqueous ethanolic extract of Pyrus pashia (Pp.Cr) exhibited spasmolytic, bronchodilator, and vaso-constrictive activities possibly through different mechanisms. The spasmolytic and bronchodilator activities are likely to be mediated through blockade of Ca2+ channels, while vasoconstrictive activity may be due to presence of a α-adrenergic, muscarinic, serotonergic, and angiotensin II agonistic component