Experimental Investigation of FRP-Strengthened RC Beam-Column Joints

The results of a comprehensive experimental program, aimed at providing a fundamental understanding of the behavior of shear-critical exterior reinforced concrete (RC) joints strengthened with fiber reinforced polymers (FRP) under simulated seismic load, are presented in this study. The role of various parameters on the effectiveness of FRP is examined through 2/3-scale testing of 18 exterior RC joints. Conclusions are drawn on the basis of certain load versus imposed displacement response characteristics, comprising the strength (maximum lateral load), the stiffness, and the cumulative energy dissipation capacity. The results demonstrate the important role of mechanical anchorages in limiting premature debonding, and they provide important information on the role of various parameters, including: area fraction of FRP; distribution of FRP between the beam and the column; column axial load; internal joint (steel) reinforcement; initial damage; carbon versus glass fibers; sheets versus strips; and effect of transverse beams.     

Shear transfer capacity along pumice aggregate concrete and high-performance concrete interfaces

This paper aims to present an experimental investigation on the behaviour of interfaces between pumice LWAC (lightweight aggregate concrete) and HPC (high-performance concrete-high-strength and fibre-reinforced), typically found in the faces and core, respectively, of hybrid precast structural sandwich panels. The evaluation of the experimental data resulted in the derivation of a semi-empirical relationship that relates the interface strength with materials strength, interface geometry and loading parameters. A brief overview of existing shear friction theories and proposed relationships, as well as a somparison among existing models and that proposed by the authors, are also outlined in the paper.     

Transitive node similarity: predicting and recommending links in signed social networks

Online social networks (OSNs) like Facebook, Myspace, and Hi5 have become popular, because they allow users to easily share content. OSNs recommend new friends to registered users based on local features of the graph (i.e., based on the number of common friends that two users share). However, OSNs do not exploit the whole structure of the network. Instead, they consider only pathways of maximum length 2 between a user and his candidate friends. On the other hand, there are global approaches, which detect the overall path structure in a network, being computationally prohibitive for huge-size social networks. In this paper, we define a basic node similarity measure that captures effectively local graph features (i.e., by measuring proximity between nodes). We exploit global graph features (i.e., by weighting paths that connect two nodes) introducing transitive node similarity. We also derive variants of our method that apply to different types of networks (directed/undirected and signed/unsigned). We perform extensive experimental comparison of the proposed method against existing recommendation algorithms using synthetic and real data sets (Facebook, Hi5 and Epinions). Our experimental results show that our FriendTNS algorithm outperforms other approaches in terms of accuracy and it is also time efficient. Finally, we show that a significant accuracy improvement can be gained by using information about both positive and negative edges.     

The AT&T Internet Difference Engine: Tracking and viewing changes on the web

The AT&T Internet Difference Engine (AIDE) is a system that finds and displays changes to pages on the World Wide Web. The system consists of several components, including a webcrawler that detects changes, an archive of past versions of pages, a tool called HtmlDiff to highlight changes between versions of a page, and a graphical interface to view the relationship between pages over time. This paper describes AIDE, with an emphasis on the evolution of the system and experiences with it. It also raises some sociological and legal issues.     

Operator context scanning to support high segmentation rates for real time license plate recognition

Introducing high definition videos and images in object recognition has provided new possibilities in the field of intelligent image processing and pattern recognition. However, due to the large amount of information that needs to be processed, the computational costs are high, making the HD systems slow. To this end, a novel algorithm applied to sliding window analysis, namely Operator Context Scanning (OCS), is proposed and tested on the license plate detection module of a License Plate Recognition (LPR) system. In the LPR system, the OCS algorithm is applied on the Sliding Concentric Windows pixel operator and has been found to improve the LPR system’s performance in terms of speed by rapidly scanning input images focusing only on regions of interest, while at the same time it does not reduce the system effectiveness. Additionally, a novel characteristic is presented, namely, the context of the image based on a sliding windows operator. This characteristic helps to quickly categorize the environmental conditions upon which the input image was taken. The algorithm is tested on a data set that includes images of various resolutions, acquired under a variety of environmental conditions.     

Distributed top-<Emphasis Type="Italic">k</Emphasis> aggregation queries at large

Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and 3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms, efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments, with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style network.     

Universal constructions that ensure disjoint-access parallelism and wait-freedom

A universal construction is a general mechanism for obtaining a concurrent implementation of an object from its sequential code. We show that there is no universal construction that is both disjoint-access parallel (guaranteeing the processes operating on different parts of an implemented object do not interfere with one another) and wait-free (guaranteeing progress for each nonfaulty process when accessing an object). In contrast, we present a universal construction which results in disjoint-access parallel, wait-free implementations of any object provided there is a bound on the number of data items accessed by each operation supported by the object.     

Experimental Investigation of Nonconventional Confinement for Concrete Using FRP

The present study investigates experimentally the behavior of concrete confined with fiber reinforced polymers (FRP) in the form of jackets which are applied according to a number of nonconventional techniques. First, the effectiveness of various jacketing configurations combined with anchors as a measure of increasing the strength and deformability of L-shaped columns is investigated. It is concluded that easy to install and low-cost anchors made of resin impregnated fibers properly placed at the reentrant corner of L-shaped columns enable excellent mobilization of confining stresses supplied by the FRP jackets. Next, a number of alternative confinement methods are investigated on concrete cylinders, aimed at quantifying the effectiveness of (1) unbonded jacketing, (2) spirally applied strips attached only at their ends, and (3) jacketing directly on concrete with mortar plastering. Although the study may be regarded as preliminary, it provides useful experimental support to a number of techniques which have the potential to open new horizons in the field of externally applied FRP for enhancing concrete confinement.     

Blockchain in global supply chains and cross border trade: a critical synthesis of the state-of-the-art,challenges and opportunities

Blockchain possesses the potential of transforming global supply chain management. Gartner predicts that blockchain could be able to track $2?T of goods and services in their movement across the globe by 2023, and blockchain will be a more than $3 trillion business by 2030. Nowadays, a growing number of blockchain initiatives are disrupting traditional business models in each sector. In this paper, we provide a timely and holistic overview of the state-of-the-art, challenges, gaps and opportunities in global supply chain and trade operations for both the private sector and governmental agencies, by synthesising a wide range of resources from business leaders, global international organisations, leading supply chain consulting firms, research articles, trade magazines and conferences. We then identify collaborative schema and future research directions for industry, government, and academia to jointly work together in ensuring that the full potential of blockchain is unleashed amidst the socioeconomic, geopolitical and technological disruptions that global supply chains and trade are facing.