The Family of MapReduce and Large Scale Data Processing Systems

In the last two decades, the continuous increase of computational power has produced an overwhelming flow of data which has called for a paradigm shift in the computing architecture and large scale data processing mechanisms. MapReduce is a simple and powerful programming model that enables easy development of scalable parallel applications to process vast amounts of data on large clusters of commodity machines. It isolates the application from the details of running a distributed program such as issues on data distribution, scheduling and fault tolerance. However, the original implementation of the MapReduce framework had some limitations that have been tackled by many research efforts in several followup works after its introduction. This article provides a comprehensive survey for a family of approaches and mechanisms of large scale data processing mechanisms that have been implemented based on the original idea of the MapReduce framework and are currently gaining a lot of momentum in both research and industrial communities. We also cover a set of introduced systems that have been implemented to provide declarative programming interfaces on top of the MapReduce framework. In addition, we review several large scale data processing systems that resemble some of the ideas of the MapReduce framework for different purposes and application scenarios. Finally, we discuss some of the future research directions for implementing the next generation of MapReduce-like solutions.Comment: arXiv admin note: text overlap with arXiv:1105.4252 by other author

Current rectification in a single molecule diode: the role of electrode coupling

We demonstrate large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction, and in addition these junctions sustain current densities larger than 10^5 A/cm^2. By following the variation of the I-V characteristics with tip-molecule separation we demonstrate unambiguously that rectification is due to asymmetric coupling to the electrodes of a molecule with an asymmetric level structure. This mechanism can be implemented in other type of molecular junctions using both organic and inorganic molecules and provides a simple strategy for the rational design of molecular diodes

Social Media and Social Transformation Movements: The Role of Affordances and Platforms

Social media (SM) have played a critical role in recent social transformation movements and yet information systems (IS) literature has only sparsely examined the role of particular SM platforms and their affordances that facilitate such collective action, and how such affordances are appropriated for decentralised forms of collaboration and cooperation. We draw on theories of affordances and collective action to identify a range of functional SM affordances, and related SM platforms, impacting online activism in the recent social transformation movements in Egypt, based on field interviews with a variety of movement participants. We identify nine perceived affordances of SM that were instrumental during the social transformation movements. When these affordances are appropriated by movement participants, they interact with and complement each other, thereby significantly impacting mobilization for social change. Our findings provide a more nuanced perspective on the role of SM in social transformation movements and have implications for both IS and collective action theories

From connective actions in social movements to offline collective actions: an individual level perspective

The purpose of this study is to investigate the role of connective action characterised by interconnection and personal communication on social media (SM) for participating in collective action in the physical world of social movements

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

AbstractThe new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections

Exploring the Role of ICT in Development: An International Perspective, A Panel Discussion

This panel will bring together a range of experts from around the world to explore the potential role of information and communications technologies (ICT) in socio-economic development. The panel will be highly interactive with each panellist speaking for a short period, which will then be followed by comments from fellow panellists and the audience. The session will be formulated as a series of topical debates on ICT and development with each panellist taking on a particular perspective, drawing from a range of national and regional contexts

A hybrid neuro--wavelet predictor for QoS control and stability

For distributed systems to properly react to peaks of requests, their adaptation activities would benefit from the estimation of the amount of requests. This paper proposes a solution to produce a short-term forecast based on data characterising user behaviour of online services. We use \emph{wavelet analysis}, providing compression and denoising on the observed time series of the amount of past user requests; and a \emph{recurrent neural network} trained with observed data and designed so as to provide well-timed estimations of future requests. The said ensemble has the ability to predict the amount of future user requests with a root mean squared error below 0.06\%. Thanks to prediction, advance resource provision can be performed for the duration of a request peak and for just the right amount of resources, hence avoiding over-provisioning and associated costs. Moreover, reliable provision lets users enjoy a level of availability of services unaffected by load variations

IL-13 R130Q single nucleotide polymorphism in asthmatic Egyptian children

Background: Asthma and its associated phenotypes are under a substantial degree of genetic control. The common variant IL-13 gene polymorphism R130Q is reported to be associated with the risk of development of asthma in some populations. Objective: We sought to study the association of IL-13 genetic variant R130Q with bronchial asthma in Egyptian children and its relation to various clinical and laboratory phenotypes of the disease. Methods: IL13 gene polymorphism (R130Q) was detected by PCR amplification followed by sequencing using pure script total DNA in 20 asthmatic patients in acute exacerbation. The results were compared to 20 healthy age and sex matched children. Results: Asthmatic children had significantly higher frequency of distribution of R130Q genotype (50%) than controls (15%). The serum total IgE as percent of high normal for age was significantly higher in asthmatic patients as compared to controls with a mean of 208.77 ±237.06% and 14.21 ± 8.08% respectively. No significant difference was observed in the mean AEC(as a percent of high normal for age) of both groups (80.85 ± 116.4% and 82.50 ± 81.4% respectively). No significant differences were observed between patients with IL-13 polymorphism R130Q and those without such polymorphism as regards family history, relation of exacerbations to upper respiratory tract infections, history of food allergy or asthma grading. Serum total IgE was significantly higher in asthmatics with GA genotype as compared to those with GG genotype with a mean of 373.25 ± 238.11% and 44.28 ± 42.65% respectively. A similar finding was also observed among the control group with a mean of 28.03 ± 9.12% and 11.77 ± 5.00% respectively. Finally a significantly higher AEC was observed in controls with GA as compared to GG genotype with a mean of 250.00 ± 51.96% versus 52.94 ± 36.87% respectively. Conclusion: The common variant IL-13 gene polymorphism R130Q is frequently associated with pediatric asthma. This variant is more active than the wild type in inducing allergic inflammation as reflected by the higher serum total IgE and AEC. Hence, IL-13R130Q may be candidate for future gene therapy targeted at reducing the ill-effects of this polymorphism.Keywords: IL-13R130Q – bronchial asthma - pediatricsEgypt J Pediatr Allergy Immunol 2010;8(1):9-1

Lymphocyte apoptosis in the pathogenesis of type 1 diabetes mellitus

Background: Beta cell apoptosis has been associated with insulin dependent diabetes mellitus (IDDM) onset in newly diagnosed diabetic patients. There is an emerging evidence that T cell-induced apoptosis is a dominant effector mechanism in diabetes mellitus type 1 (DM1). Pancreatic β-cells derived from newly diagnosed type 1 diabetics were found to have increased cell surface expression of Fas (CD95) compared to β-cells from healthy subjects. Objective: The study investigates the spontaneous lymphocyte apoptosis via CD95 molecule expression to demonstrate activation induced cell death in children with high risk of DM1 and in type 1 diabetics under insulin therapy. Methods: This study comprised 90 children and adolescents, divided into 3 groups. G(1) comprised 40 type-1 diabetics, their ages ranging from 8.0 to 17.0 years and disease duration between 2.0 and 12.0 years. G(2) (prediabetics) included 30 euglycaemic subjects who were first degree relatives of type 1 diabetics, with normal fasting blood glucose and positive first phase insulin release (FPIR) and/or positive islet cell (ICA) or glutamic acid decarboxylase (GAD) antibodies. G(3) comprised 20 healthy, age and sex matched subjects with no clinical or laboratory signs or family history of type-1DM. Patients were subjected to clinical evaluation with special emphasis on signs suggestive of microvascular complications. The study measurements included random blood sugar (RBS), glycosylated hemoglobin (HbA1c), urinary microalbumin assay and flow cytometric assessment of apoptosis by measuring CD95 percentage expression on CD3 lymphocytes. Results: The percentage of CD95 positive T-lymphocytes was significantly higher in prediabetics than in type-1 diabetics and controls (57.687±6.68, 45.01±6.648,16.75±4.98% respectively; p < 0.001). CD3 positive lymphocytes were significantly lower in prediabetics than type-1 diabetics and controls (52.93±11.64, 66.23±7.04, 63.910±3.4% respectively; p < 0.001). The percentage of CD95 on T-lymphocytes could not be correlated with age, insulin dose and RBS, but HbA1c was positively correlated with both CD3 lymphocytes and CD95% expression. Complicated type-1 diabetics showed higher CD95% expression compared to noncomplicated patients. Conclusion: Peripheral blood lymphocytes with CD95 antigen expression are increased in prediabetics. As CD95 is an important receptor for activation-induced cell death, CD95 mediated apoptosis could play a potential role in the pathogenesis of DM1.Keywords: lymphocyte apoptosis; CD95 system; type 1 DM; prediabetesEgypt J Pediatr Allergy Immunol 2008; 6(2): 57-6