Balancing user preferences for aircraft schedule recovery during irregular operations

In this paper, the irregular operations problem is approached for the first time in a way that allows an airline to provide for schedule recovery with minimal deviations from the original aircraft routings. A network model with side constraints is presented in which delays and cancellations are used to deal with aircraft shortages in a way that ensures a significant portion of the original aircraft routings remain intact. The model is flexible, allowing user preferences in the objective, and thereby reflecting the immediate concerns of the decision-maker in the recovery schedule. The model can be tailored by airline operations personnel to emphasize differing solution characteristics. Fleet data provided by Continental Airlines are used to demonstrate the approach. Extensive testing indicates that optimal or near-optimal solutions are routinely obtained from the LP relaxation of the network formulation. When integrality is not achieved, a rounding heuristic is provided that finds feasible solutions within a small fraction of the optimum.     

The principles of pedestrian route choice

Pedestrian route choice, the process by which individuals decide on their walking path between two locations, is a fundamental problem across disciplines. Because this behaviour is investigated from different conceptual and methodological angles, and because it strongly depends on the environmental context, it is challenging to establish a systematic framework for research. Here, by reviewing previous work, we identify four principles for pedestrian route choice that are relevant across disciplines. First, ‘information perception’ deals with how pedestrians can perceive information selectively and purposely, given the limited available information. Second, ‘information integration’ considers how pedestrians subjectively integrate environmental spatial information into mental representations. Third, ‘responding to information’ is concerned with how pedestrians tend to be attracted and repelled by specific attributes individually and how this can lead to positive or negative feedback loops across many individuals. Fourth ‘decision-making mechanisms'' describe how pedestrians trade off the evidence provided by different attributes. How pedestrians perceive, integrate, respond to, and act upon information is not fixed but varies with the context. We give examples for each principle and explain how these principles shape pedestrian choice behaviours. We hope this contribution provides a systematic overview of the field and helps to spark inspiration among specialists.     

Spatial econometrics models for congestion prediction with in-vehicle route guidance

The congestion dependence relationship among links using microsimulation is explored, based on data from a real road network. The work is motivated by recent innovations to improve the reliability of Dynamic Route Guidance (DRG) systems. The reliability of DRG systems can be significantly enhanced by adding a function to predict the congestion in the road network. The application of spatial econometrics modelling to congestion prediction is also explored, by using historical traffic message channel (TMC) data stored in the vehicle navigation unit. The nature of TMC data is in the form of a time series of geo-referenced congestion warning messages, which is generally collected from various traffic sources. The prediction of future congestion could be based on the previous year of TMC data. Synthetic TMC data generated by microscopic traffic simulation for the network of Coventry are used in this study. The feasibility of using spatial econometrics modelling techniques to predict congestion is explored. The results are presented at the end.     

A review of game-theoretic models of road user behaviour

This paper reviews game-theoretic models that have been developed to explain road user behaviour in situations where road users interact with each other. The paper includes the following game-theoretic models:

1.

A general model of the interaction between road users and their possible reaction to measures improving safety (behavioural adaptation).     

The road user behaviour of school students in Iran

The present study developed a Persian version of the Adolescent Road User Behaviour Questionnaire (ARBQ) and investigated the psychometric properties of the scale in a sample of school students in the province of Tehran (Iran). In total 1111 adolescents completed the Persian version of the ARBQ. Exploratory factor analysis, using the shortened 21-item version of the scale revealed the presence of three reliable factors which were also supported using confirmatory factor analysis.     

The road user behaviour of school students in Belgium

The present study aimed to investigate both the on road behaviour of Belgian school students and the validity of the Adolescent Road User Behaviour Questionnaire (ARBQ) in a sample of students attending school in Belgium. In total, 294 adolescents completed the ARBQ along with measures of their self-reported accident involvement and sensation seeking behaviour. Confirmatory Factor Analysis supported the original factor structure of: “unsafe road crossing”, “playing on the road” and “planned protective behaviour” for the 21-item version of the questionnaire, but not for the full scale. Males were found to engage more often in unsafe crossing behaviour and playing on the roads. There were also age differences, with unsafe road crossing increasing with age and engagement in planned protective behaviours improving with age. Those who reported being involved in an accident also reported more frequent engagement in unsafe crossing, playing on the roads, thrill seeking behaviour and lower levels of behaviour inhibition. Therefore, this study confirms that the ARBQ is a useful tool for investigating safety-related behaviours that contribute to accident involvement.     

Common preferences of different user segments as basis for intelligent transport system: case study ? Finland

The ultimate purpose of the transport system is to serve the needs and expectations of the end users, who in turn shape the system by their own behaviour, actions and investments. This work examines, within the framework of the Large Technological Systems theory the possibility to categorise users of the transport system into homogeneous segments on the basis of their differences in daily mobility and transportation of goods. Furthermore, the potential to deepen this segmentation to describe the needs of, but later in the policy process also the social acceptance by, different user groups for new transport technology or policy, is examined     

The contribution of on-road studies of road user behaviour to improving road safety

For over 40 years transport safety researchers have been using methods of vehicle instrumentation to gain greater insights into the factors that contribute to road user crash risk and the associated crash factors. In the previous decade in particular the widespread availability of lower cost and more advanced methods of vehicle instrumentation and recording technologies are supporting the increasing number of on-road research studies worldwide. The design of these studies ranges from multi-method studies using instrumented test vehicles and defined driving routes, to field operational tests, through to much larger and more naturalistic studies. It is timely to assess the utility of these methods for studying the influences of driver characteristics and states, the design and operation of the road system, and the influences of in-vehicle technologies on behaviour and safety for various road user groups. This special issue considers the extent to which on-road studies using vehicle instrumentation have been used to advance knowledge across these areas of road safety research. The papers included in this issue illustrate how research using instrumented test vehicles continues to generate new knowledge, and how the larger scale United States and European naturalistic and field operational test studies are providing a wealth of data about road user behaviour in real traffic. This is balanced with a number of studies that present methodological developments in data collection and analysis methods that, while promising, need further validation. The use of on-road methods to accurately describe the behaviours occurring in everyday real-world conditions, to quantify risks for safety critical events, and an improved understanding of the factors that contribute to risk, clearly has huge potential to promote further road trauma reductions.     

Prospect theory based estimation of drivers’ risk attitudes in route choice behaviors

This paper applied prospect theory (PT) to describe drivers’ route choice behavior under Variable Message Sign (VMS), which presented visual traffic information to assist them to make route choice decisions. A quite rich empirical data from questionnaire and field spot was used to estimate parameters of PT. In order to make the parameters more realistic with drivers’ attitudes, they were classified into different types by significant factors influencing their behaviors. Based on the travel time distribution of alternative routes and route choice results from questionnaire, the parameterized value function of each category was figured out, which represented drivers’ risk attitudes and choice characteristics. The empirical verification showed that the estimates were acceptable and effective. The result showed drivers’ risk attitudes and route choice characteristics could be captured by PT under real-time information shown on VMS. For practical application, once drivers’ route choice characteristics and parameters were identified, their route choice behavior under different road conditions could be predicted accurately, which was the basis of traffic guidance measures formulation and implementation for targeted traffic management. Moreover, the heterogeneous risk attitudes among drivers should be considered when releasing traffic information and regulating traffic flow.     

基于自适应空间正则化和畸变抑制的相关滤波跟踪

针对背景感知相关滤波器的空间正则化权重固定,不适应目标变化和增大搜索区域,易引入背景噪声导致滤波器判别力下降等问题,本文提出一种基于自适应空间正则化和畸变抑制的相关滤波跟踪算法。首先提取FHOG特征、CN特征和灰度特征以增强算法模型对目标的表达能力;其次,在目标函数中加入畸变抑制项来约束当前帧的响应图,增强滤波器的判别能力,以缓解滤波器模型退化问题;最后,在目标函数中加入自适应空间正则化项使空间正则化权重能够随着目标的变化而更新,使得滤波器能充分利用目标的多样性信息。本文在公开数据集OTB-2013、OTB-2015和VOT2016上进行实验,以对所提算法进行评估。实验结果表明：本文算法速度为20 f/s,距离精度和成功率等评估指标均优于对比算法,在遮挡、背景干扰、旋转变化等多种复杂场景下都有良好的鲁棒性。     

Compressive behaviour of SiC/ncsc reinforced Mg composite processed through powder metallurgy route

In this present work nano coconut shell charcoal (ncsc) and silicon carbide (SiC) particulates were reinforced with AZ31B Mg alloy and suitable magnesium composite was developed by using the powder metallurgy technique followed by hot extrusion. Density measurement of the Mg composites revealed that the addition of ncsc significantly improved the density of the composites and porosity measurement showed minimal porosity. The microstructure of the composites showed even distribution of the ncsc in the AZ31B/3SiC Mg composite. The compressive and impact behaviour of the samples were characterized, the results showed that on increasing the weight percentage of ncsc in AZ31B/3SiC/0.5ncsc Mg composites the mechanical properties such as ultimate compressive strength, 0.2% yield strength, ductility and impact strength decreased. The scanning electron microscope (SEM) analysis of fractured surface of AZ31B Mg alloy and AZ31B/3SiC/0.5ncsc Mg composites showed quasi-cleavage fracture. The presence of ncsc above 0.5 wt% composites revealed mixture of quasi cleavage planes and some dimples.     

Hot deformation behaviour of aluminium alloy 6061/SiCp MMCs made by powder metallurgy route

Abstract

The hot deformation behaviour of a 20 vol.-%SiC particle reinforced Al alloy 6061 composite and Al alloy 6061, made via a powder metallurgy (PM) route and treated by a T4 temper, were studied by compression testing over a range of temperatures (300–500°C)and at strain rates of 0.005, 0.05, and 0.09 s^-1. It was observed that the flow stresses of the composites were significantly higher than those of the alloy at lower deformation temperatures. However, the stress–strain curves of both the composite and the alloy showed significant softening during deformation at the lowest strain rate, the softening for the composite being faster than that of the alloy. The activation energy for hot deformation was determined for different strains, using a power law equation, and was found to change significantly with strain for both the alloy and the composite. This phenomenon was explained by the occurrence of dynamic precipitation and coarsening during deformation.     

A review of the FDA draft guidance document for software validation: guidance for industry.

A Draft Guidance Document (Version 1.1) was issued by the United States Food and Drug Administration (FDA) to address the software validation requirement of the Quality System Regulation, 21 CFR Part 820, effective June 1, 1997. The guidance document outlines validation considerations that the FDA regards as applicable to both medical device software and software used to "design, develop or manufacture" medical devices. The Draft Guidance is available at the FDA web site http:@www.fda.gov/cdrh/comps/swareval++ +.html. Presented here is a review of the main features of the FDA document for Quality System Regulation (QSR), and some guidance for its implementation in industry.     

Fundamentals of product ecosystem design for user experience

Recognizing the importance of user experience (UX) in product ecosystems, this paper examines the fundamental issues underlying product ecosystem design, including implications of a product ecosystem, the notion of the ambience, as well as UX in terms of affect and cognition. A conceptual model is outlined to elucidate the critical factors and the operational mechanism of product ecosystem design for user satisfaction. A technical framework of product ecosystem design for UX is presented, consisting of three consecutive and iterative stages, namely, affective-cognitive need acquisition, affective-cognitive analysis, and affective-cognitive fulfillment. An application to subway station design is reported to illustrate the key techniques for product ecosystem design, including ambient intelligence, data mining, Petri-net modeling, and simulation.     

Investigations into dry-sliding wear behaviour of a novel composite (aluminium-magnesium-silicon-copper-silicon carbide) produced by powder metallurgy route

Metal-matrix aluminium composites are satisfactory successor not only for steels, but also for aluminium-alloys in several automotive units and components. There are various paths to get light-weight materials with-out compromising their toughness, strength and safety demands. Tests on dry-sliding or un-lubricated pin-on-disc tests can be performed to obtain the wear-characteristics of metal-matrix composites built on aluminum. In the present study, we studied the behavior of wear resistance during sliding of metal matrix aluminium composites (AMMC) at sliding speeds of 1.5 m/s and loads of 20 N and 40 N in a normal environment, and experiments have been conducted using pin-on-disk tribometer (Make: DUCOM tribometer). The composites were manufactured by powder treatment and presented a number of problems, such as defective bonds and inter-facial product reactions, which alter the tribological and mechanical properties. The results have shown that wear-rates of the prepared composites are much lesser than those of matrix-alloy and decreased further with increasing silicon carbide content. As the normal loads increases, the cracks and combination of abrasions, delimitation and wear of the adhesives of silicon carbide particles were observed. The composite samples were studied using a scanning electron microscope before and after the wear tests and systematically analysed.     

Impact of response delay and training on user performance with text-based and graphical user interfaces for engineering design

With recent computer advances, visualization techniques are becoming more prevalently used as decision support tools for parametric design and engineering optimization. Despite the apparent advantages of visualization techniques, we have found little evidence in the engineering design literature that assesses the impact of fast graphical design interfaces on the efficiency and effectiveness of engineering design decisions. In this paper, we present experimental results from an I-beam design problem where the importance of rapid feedback is investigated by incorporating time delays in the software response to “mimic” computationally expensive design analyses. Design efficiency is measured by recording the completion time for solving the design problem, and design effectiveness is measured by calculating the error between a submitted design and the known optimum. The impact of graphical feedback is examined by comparing user performance on three different design interfaces to determine if their functionality and graphical capabilities mediate the impact of response delays in the software or the amount of training needed. Experimental results indicate that, on average, error increased by 280% and completion time increased by 33% when a delay of 1.5 s was present, and the perceived workload significantly increased as well. Meanwhile, user performance improved and perceived workload decreased as the “richness” of the design interface increased. The combination of a rich interface with a fast response time, therefore, will lead to the “best” interface as one might surmise, but our work provides the first empirical evidence of the effect of response delay on user performance within a realistic engineering design setting. Implications for interface development for engineering design are explored within the context of our findings, as are suggestions for future work.