Immunity-based hybrid evolutionary algorithm for multi-objective optimization in global container repositioning

The development of evolutionary algorithms for optimization has always been a stimulating and growing research area with an increasing demand in using them to solve complex industrial optimization problems. A novel immunity-based hybrid evolutionary algorithm known as Hybrid Artificial Immune Systems (HAIS) for solving both unconstrained and constrained multi-objective optimization problems is developed in this research. The algorithm adopts the clonal selection and immune suppression theories, with a sorting scheme featuring uniform crossover, multi-point mutation, non-dominance and crowding distance sorting to attain the Pareto optimal front in an efficient manner. The proposed algorithm was verified with nine benchmarking functions on its global optimal search ability as well as compared with four optimization algorithms to assess its diversity and spread. Sensitivity analysis was also carried out to investigate the selection of key parameters of the algorithm. It is found that the developed immunity-based hybrid evolutionary algorithm provides a useful means for solving optimization problems and has successfully applied to the problem of global repositioning of containers, which is one of a constrained multi-objective optimization problem. The developed HAIS will assist shipping liners on timely decision making and planning of container repositioning operations in global container transportation business in an optimized and cost effective manner.     

On detecting faults for Boolean expressions

Fault based testing aims at detecting hypothesized faults based on specifications or program source. There are some fault based techniques for testing Boolean expressions which are commonly used to model conditions in specifications as well as logical decisions in program source. The MUMCUT strategy has been proposed to generate test cases from Boolean expressions. Moreover, it detects eight common types of hypothesized faults provided that the original expression is in irredundant disjunctive normal form, IDNF. Software practitioners are more likely to write the conditions and logical decisions in general form rather than IDNF. Hence, it is interesting to investigate the fault detecting capability of the MUMCUT strategy with respect to general form Boolean expressions. In this article, we perform empirical studies to investigate the fault detection capability of the MUMCUT strategy with respect to general form Boolean expressions as well as mutated expressions. A mutated expression can be obtained from the original given Boolean expression by making a syntactic change based on a particular type of fault.

Situation awareness acquired from monitoring process plants – the Process Overview concept and measure

We introduce Process Overview, a situation awareness characterisation of the knowledge derived from monitoring process plants. Process Overview is based on observational studies of process control work in the literature. The characterisation is applied to develop a query-based measure called the Process Overview Measure. The goal of the measure is to improve coupling between situation and awareness according to process plant properties and operator cognitive work. A companion article presents the empirical evaluation of the Process Overview Measure in a realistic process control setting. The Process Overview Measure demonstrated sensitivity and validity by revealing significant effects of experimental manipulations that corroborated with other empirical results. The measure also demonstrated adequate inter-rater reliability and practicality for measuring SA based on data collected by process experts.

Practitioner Summary: The Process Overview Measure is a query-based measure for assessing operator situation awareness from monitoring process plants in representative settings.     

CyberWalk: a web-based distributed virtual walkthrough environment

A distributed virtual walkthrough environment allows users connected to the geometry server to walk through a specific place of interest, without having to travel physically. This place of interest may be a virtual museum, virtual library or virtual university. There are two basic approaches to distribute the virtual environment from the geometry server to the clients, complete replication and on-demand transmission. Although the on-demand transmission approach saves waiting time and optimizes network usage, many technical issues need to be addressed in order for the system to be interactive. CyberWalk is a web-based distributed virtual walkthrough system developed based on the on-demand transmission approach. It achieves the necessary performance with a multiresolution caching mechanism. First, it reduces the model transmission and rendering times by employing a progressive multiresolution modeling technique. Second, it reduces the Internet response time by providing a caching and prefetching mechanism. Third, it allows a client to continue to operate, at least partially, when the Internet is disconnected. The caching mechanism of CyberWalk tries to maintain at least a minimum resolution of the object models in order to provide at least a coarse view of the objects to the viewer. All these features allow CyberWalk to provide sufficient interactivity to the user for virtual walkthrough over the Internet environment. In this paper, we demonstrate the design and implementation of CyberWalk. We investigate the effectiveness of the multiresolution caching mechanism of CyberWalk in supporting virtual walkthrough applications in the Internet environment through numerous experiments, both on the simulation system and on the prototype system.     

User-centric content negotiation for effective adaptation service in mobile computing

We address the challenges of building a good content adaptation service for mobile devices and propose a decision engine that is user-centric with QoS awareness, which can automatically negotiate for the appropriate adaptation decision to use in the synthesis of an optimal adapted version. The QoS-sensitive approach complements the lossy nature of the transcoding operations. The decision engine will look for the best trade off among various parameters in order to reduce the loss of quality in various domains. Quantitative methods are suggested to measure the QoS of the content versions in various quality domains. Based on the particular user perception and other contextual information on the client capability, the network connection, and the requested content, the proposed negotiation algorithm will determine a content version with a good aggregate score. We have built a prototype document adaptation system for PDF documents to demonstrate the viability of our approach.     

Trying to adopt systems development methodologies — a case-based exploration of business users' interests

Information systems methodologies are an important component of the IS infrastructure and a primary device for organizing systems development work. Evidence suggests that methodology adoption and use are problematic. This research seeks to generate insight into business users' interest in adoption through detailed examination of a case. A framework is developed for organizing relevant research findings. The field research methods are described and details of the case reported. The case highlights the role of business managers in methodology adoption and the influence of business pressures originating in the strategic environment. Analysis shows the organizing framework to require extension to include a more direct role for business decision makers. it is argued that previous research has obscured the legitimate concern of business with systems development methodologies. As business increasingly asserts its interest in and control over IS, it will be necessary to give greater consideration to the needs of business in the selection and adoption of methodologies.     

Investigation on strengthening and strain sensing techniques for concrete structures using FRP composites and FBG sensors

This paper reports the results of an experimental investigation on the mechanical properties of the laboratory size rectangular concrete beams with the notch formation on the tension surface strengthened by using fibre reinforced plastic composites, Fibre-optic Bragg grating (FBG) sensors have been embedded at the interface between the concrete surface and external bonded composites to measure the strain variations when the strengthened structures were subjected to three-point bending load. Multiplexing strainsensing technique has been used for measuring the strains in different locations of the beam by using one single optical fibre. External bonded strain gauges were also attached on the surfaces of composites to measure the surface strain and the results were compared with that obtained from the embedded FBG sensors. The observation in the experiments showed that the flexural load capacity of the strengthened concrete beams was increased significantly after strengthening by laying-up the compsite laminate for both plain and notched concrete structures. Debond and concrete failure occurred at the plate end region when the thick composite laminate was used. The embedded FBG sensors could provide the indication to the operator when the structure serviced in strange conditions. The strains measured at the interfaces from the sensors were higher than that from the surface bonded strain gauges in general.

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Résumé Les investigations expérimentales présentées dans cet article portent sur les propriétés mécaniques d'éprouvettes de béton rectangulaires entaillées en surface de la zone de tension puis renforcées au moyen de polymères renforcés de fibres (FRP). Des capteurs à réseau de Bragg à fibre optique (FBG) ont été placés à l'interface entre le béton et le composite afin de mesurer les variations des contraintes quand la structure est soumise à une charge de flexion en trois points. Un multiplexage des capteurs est utilisé pour mesurer les contraintes en différents points de l'éprouvette en n'utilisant qu'une seule fibre optique. Des jauges d'extensométrie ont aussi été placées en surface du composite, leurs résultats sont alors comparés à ceux obtenus à partir des capteurs FBG. Ces expériences ont montré que la résistance au fléchissement des poutres est nettement améliorée grace au renforcement par le composite, ce tant pour les structures intates, que pour les éprouvettes entaillées. Lorsque la poutre est renforcée par une plaque épaisse du composite laminé, la rupture de la liaison avec le béton, ainsi que la rupture du béton, ont lieu au bord de cette plaque. Les capteurs à réseau de Bragg à fibre optique permettent de fournir des indications à l'opérateur lorsque la structure est en service dans des conditions peu usuelles. Les contraintes mesurées par les capteurs. FBG aux interfaces sont en général plus importantes que celles mesurées par les jauges situées en surface du composite.

     

Aryl functionalization as a route to band gap engineering in single layer graphene devices

Chemical functionalization is a promising route to band gap engineering of graphene. We chemically grafted nitrophenyl groups onto exfoliated single-layer graphene sheets in the form of substrate-supported or free-standing films. Our transport measurements demonstrate that nonsuspended functionalized graphene behaves as a granular metal, with variable range hopping transport and a mobility gap ～0.1 eV at low temperature. For suspended graphene that allows functionalization on both surfaces, we demonstrate tuning of its electronic properties from a granular metal to a semiconductor in which transport occurs via thermal activation over a transport gap ～80 meV from 4 to 300 K. This noninvasive and scalable functionalization technique paves the way for CMOS-compatible band gap engineering of graphene electronic devices.