Coating of gold nanoparticles by thermosensitive poly(N-isopropylacrylamide) end-capped by biotin

Gold nanoparticles (NPs) were prepared by reduction of HAuCl₄ in aqueous solution and stabilized by poly(N-isopropylacrylamide) (PNIPAM). PNIPAM was prepared by two distinct routes: (i) conventional free-radical polymerization leading to polymer without any reactive end-group, and (ii) Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization with 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP) as a RAFT agent. PNIPAM with low polydispersity was then end-capped by an α-carboxylic acid and an ω-trithiocarbonate that was converted into an ω-thiol upon hydrolysis. This hetero-telechelic polymer was analyzed by mass spectroscopy, size exclusion chromatography (SEC) and ¹H NMR. Even without thiol end-group, known for chemisorption onto gold, PNIPAM was effective in stabilizing gold NPs (∼1-5 nm). The thermosensitivity of PNIPAM at the surface of gold NPs was, however, dependent on the molecular weight of the chains. Finally, the α-carboxyl end-group of PNIPAM was used to anchor biotin, which is indeed known for complexation with avidin, which is a possible strategy for the coated gold NPs to be involved as building blocks in supramolecular assemblies. TEM and UV-vis spectroscopy were used to characterize the gold nanoparticles.     

Construction Business Competitiveness and Global Benchmarking

The focus of this paper is on developing “quality” and sustainable construction businesses capable of riding market shifts and growing both nationally and internationally. Knowledge of current management tools and techniques will no doubt prove useful in the quest for transforming a nonperforming business. However, no long lasting effect can be expected unless attention is paid to the fundamental principles and practices that govern organizational behavior, including the views an organization has of its customers, competitors, and itself. Commercial performance of organizations has increasingly become not only dependent on resource efficiency, but also on retooling and aggressive new business development initiatives as well as reduction in base production and operational costs. The human factors and mental models that people have within any given organization profoundly affect the success or failure of that organization. In this paper a critical review of the current concepts and techniques influencing construction organizations is offered with a focus on people and organizational improvements. A set of critical success factors is then distilled, followed by a systematic process of applying the same to achieve success.     

Design and performance of active power filters

This article has demonstrated the feasibility of a three phase active filter based on a half-bridge topology. Design guidelines for the power circuit have been derived and applied to a 5 kVA IGBT laboratory prototype. In the single phase mode, the active filter can reduce the low frequency harmonic content in the AC line to below 1% excluding the harmonics due to switching action of the converter. In the three phase mode, line currents are corrected under balanced and unbalanced conditions. The neutral current is reduced significantly.     

Security and performance enhancement of AODV routing protocol

A mobile ad hoc networks (MANET) is a decentralized, self‐organizing, infrastructure‐less network and adaptive gathering of independent mobile nodes. Because of the unique characteristics of MANET, the major issues to develop a routing protocol in MANET are the security aspect and the network performance. In this paper, we propose a new secure protocol called Trust Ad Hoc On‐demand Distance Vector (AODV) using trust mechanism. Communication packets are only sent to the trusted neighbor nodes. Trust calculation is based on the behaviors and activities information of each node. It is divided in to trust global (TG) and trust local (TL). TG is a trust calculation based on the total of received routing packets and the total of sending routing packets. TL is a comparison between total received packets and total forwarded packets by neighbor node from specific nodes. Nodes conclude the total trust level of its neighbors by accumulating the TL and TG values. The performance of Trust AODV is evaluated under denial of service/distributed denial of service (DOS/DDOS) attack using network simulator NS‐2. It is compared with the Trust Cross Layer Secure (TCLS) protocol. Simulation results show that the Trust AODV has a better performance than TCLS protocol in terms of end‐to‐end delay, packet delivery ratio, and overhead. Next, we improve the performance of Trust AODV using ant algorithm. The proposed protocol is called Trust AODV + Ant. The implementation of ant algorithm in the proposed secure protocol is by adding an ant agent to put the positive pheromone in the node if the node is trusted. Ant agent is represented as a routing packet. The pheromone value is saved in the routing table of the node. We modified the original routing table by adding the pheromone value field. The path communication is selected based on the pheromone concentration and the shortest path. Trust AODV + Ant is compared with simple ant routing algorithm (SARA), AODV, and Trust AODV under DOS/DDOS attacks in terms of performance. Simulation results show that the packet delivery ratio and throughput of the Trust AODV increase after using ant algorithm. However, in terms of end‐to‐end delay, there is no significant improvement. Copyright © 2014 John Wiley & Sons, Ltd.     

Fast edge-based stereo matching approach for road applications

Several vision-based road applications use stereo vision algorithms, and they generally must be fast to be applied in real time. The main problem in stereo vision is the stereo matching problem, which consists in finding correspondences between two stereo images. In this paper, we present a new fast edge-based stereo matching approach devoted to road applications. Two passes of the dynamic programming algorithm are applied to estimate the final disparity map. The matching results of the first pass are only exploited to compute an initial disparity map (IDM). The so-called guiding edge points (GEPs) together with disparity ranges, i.e., possible matches, are derived from the IDM. In the second pass, the disparity ranges are used to reduce the search space as well as the mismatches and the GEPs to control and guide the matching process to the optimal solution. The proposed method has been tested on both real and virtual stereo images, it has been compared to a recently proposed method, and the results are satisfactory.     

Project and program diagnostics: A systemic approach

This paper focuses on the theory and application of diagnostic concepts to assess the health of large projects or programs at any point in their life relative to the desired targets. The author presents a comprehensive project health check methodology. Project diagnostics is not to be confused with project progress measurement and control or project management maturity models as the objective is to see if the project team applies a systemic approach to the planning and management of the project. Its purpose is not to assess the project progress achieved at a given time and compare that to plans. Nor does it aim to assess the maturity of the application of a particular project management methodology/standard. The health of a project/program at a given time is found by evaluating the actual practices applied to manage a raft of variables which collectively characterise the management practice on that project.The technique – referred to as project health check or ‘PH-Check’ – has been computerised for ease of application. It provides a graphical picture of the heath of a project at the time of assessment. The results of the project health check can then be correlated with the results obtained from traditional project progress measurement tools. This correlation will yield greater understanding of the management of the enabling factors and their influence on project behaviour and results. This paper presents the PH-Check methodology and its underpinning concepts.