The influence of training level on manual flight in connection to performance,scan pattern,and task load

This work focuses on the analysis of pilots’ performance during manual flight operations in different stages of training and their influence on gaze strategy. The secure and safe operation of air traffic is highly dependent on the individual performances of the pilots. Before becoming a pilot, he/she has to acquire a broad set of skills by training to pass all the necessary qualification and licensing standards. A basic skill for every pilot is manual control operations, which is a closed-loop control process with several cross-coupled variables. Even with increased automation in the cockpit, the manual control operations are essential for every pilot as a last resort in the event of automation failure. A key element in the analysis of manual flight operations is the development over time in relation to performance and visual perception. An experiment with 28 participants (including 11 certified pilots) was conducted in a Boeing 737 simulator. For defined flight phases, the dynamic time warping method was applied to evaluate the performance for selected criteria, and eye-tracking methodology was utilized to analyze the gaze-pattern development. The manipulation of workload and individual experience influences the performance and the gaze pattern at the same time. Findings suggest that the increase of workload has an increased influence on pilots depending on the flight phase. Gaze patterns from experienced pilots provide insights into the training requirements of both novices and experts. The connection between workload, performance and gaze pattern is complex and needs to be analyzed under as many differing conditions. The results imply the necessity to evaluate manual flight operations with respect to more flight phases and a detailed selection of performance indications.

     

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

The construction of dams significantly alters flow and sediment regimes with subsequent deleterious effects on the morphological and ecological character of rivers. Effective experimental floods can ameliorate the downstream geomorphic impacts of dams. The traditional view is that large floods are required to perform effective geomorphic work, and the geomorphic outcomes of small floods are often overlooked. Many river restoration frameworks do not consider small floods. Yet, there is evidence that the hydrological characteristics that ameliorate specific geomorphic impacts in a river are unique to each river, and a customised approach to setting the right mix of floods (including small experimental floods) is needed. In this study, we modify an existing flood effectiveness model developed for large floods, for determining the geomorphic effectiveness of small floods in a highly regulated Australian river. Two flood classes were added to the model (medium peak stream power and moderate total energy expenditure), and the flood power characteristics were rescaled to reflect the relative difference in the magnitude of the small floods and the magnitude of the geomorphic work performed. Using a step‐wise approach, this customised model determined the geomorphic effectiveness of small floods. The best flood for ameliorating the geomorphic impacts of flow regulation had medium to long duration (10 to 51 days), high peak unit stream power (77 to 123 Wm^?2) and moderate to large total energy expenditure (78,600 to 342,320 × 10³ J). This approach to determining flood effectiveness for small floods is applicable to other geomorphically impacted river channels downstream of dams and can be used to inform experimental flood releases for geomorphic outcomes.     

Structure/property relationships in sintered and thermally sprayed WC-Co

Thermally sprayed WC-Co is widely used as a wear-resistant coating for a variety of applications. Although it is well established that thermal spray processes significantly affect chemistry, microstructure, and the phase distribution of WC-Co coatings, little is known about how these changes influence wear resistance. In this study, the microstructure and wear behavior of sintered and thermally sprayed WC-Co materials are examined. Powders of WC-12 wt% Co and WC-17 wt% Co were pressed and sintered, as well as thermally sprayed by high-velocity oxy-fuel (HVOF), air plasma spray (APS), and vacuum plasma spray (VPS) techniques. Results indicated considerable differences in the resulting microstructures, mechanical properties, and wear resistance. The thermally sprayed coatings showed anisotropic fracture toughness, whereas the sintered materials did not. It was also shown that a combined mechanical property/microstructure parameter, based on considerations of indentation fracture mechanisms, can be used in most cases to describe abrasive and erosive wear resistance of thermally sprayed WC-Co materials as follows: Wear resistance a whereK _ic is the indentation fracture toughness,H is hardness, andV ^Co _f is the volume fraction of cobalt. This relationship provides a means for assessing wear resistance of WC-Co coatings intended for industrial applications requiring abrasion and/or erosion resistance.     

A study of the tool-chip interface contact problem under low cutting velocity with an elastic cutting tool

To understand the effects of elastic deformation of the tool and the crater phenomenon generated by the cutting force and high pressure during metal cutting processing on the cutting process, an iterative mathematical model for calculating the tool-chip contact is developed in this paper under the assumption of elastic cutting tools. In this model, the finite-element method is used to simulate the cutting of mild steel by a cutting tool of three different materials. The results obtained in the simulation are found to match experimental data reported by related studies. The simulation results also indicate that tools with a smaller stiffness produce greater elastic deformation. Further, decrease of the rake angle due to elastic deformation of the tool can result in greater difficulty in internal deformation of the material and an increase in cutting force. The micro-crater phenomenon on the tool face generated by high pressure at the tool-chip interface is the preliminary symptom of crater wear on the tool face. Therefore, under some machining conditions, such as in precision machining or in automation processing where tool compensation is required, the phenomenon of elastic deformation of the tool must be considered carefully to ensure product precision.     

Microstructure and tensile properties of squeeze cast magnesium alloy AM50

High-pressure die cast magnesium alloy AM50 is currently used extensively in large and complex shaped thin-wall automotive components. For further expansion of the alloy usage in automobiles, novelmanufacturing processes need to be developed. In this study, squeeze casting of AM50 alloy with a relatively thick cross section was carried out using a hydraulic press with an applied pressure of 70 MPa. Microstructure and mechanical properties of the squeeze cast AM50 with a cross-section thickness of 10 mm were characterized in comparison with the die cast counterpart. The squeeze cast AM50 alloy exhibits virtually no porosity in the microstructure as evaluated by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength and elongation, for the squeeze cast samples over the conventional high-pressure die cast parts. The analysis of tensile behavior show that the strain-hardening rate during the plastic deformation of the squeeze cast specimens is constantly higher than that of the die cast specimens. The scanning electron microscopy fractography evidently reveals the ductile fracture features of the squeeze cast alloy AM50.     

A computational approach to measuring the correlation between expertise and social media influence for celebrities on microblogs

Social media influence analysis, sometimes also called authority detection, aims to rank users based on their influence scores in social media. Existing approaches of social influence analysis usually focus on how to develop effective algorithms to quantize users’ influence scores. They rarely consider a person’s expertise levels which are arguably important to influence measures. In this paper, we propose a computational approach to measuring the correlation between expertise and social media influence, and we take a new perspective to understand social media influence by incorporating expertise into influence analysis. We carefully constructed a large dataset of 13,684 Chinese celebrities from Sina Weibo (literally ”Sina microblogging”). We found that there is a strong correlation between expertise levels and social media influence scores. Our analysis gave a good explanation of the phenomenon of “top across-domain influencers”. In addition, different expertise levels showed influence variation patterns: e.g., (1) high-expertise celebrities have stronger influence on the “audience” in their expertise domains; (2) expertise seems to be more important than relevance and participation for social media influence; (3) the audiences of top expertise celebrities are more likely to forward tweets on topics outside the expertise domains from high-expertise celebrities.     

Protecting Business Secrets in an EDI/CALS Environment

ABSTRACT

Communicating with confidential data requires special attention in a mobile agents environment, especially when the other hosts must be prevented from eavesdropping on the communication. We propose a communication model for secured communication between the agents belonging to publishers and consumers data. Confidentiality is ensured using our on-the-fly encryption-decryption sequence using ElGamal system to directly convert the message or plaintext into one that is encrypted directly with the public key of consumer. The scheme ensures that the data possessed by the agents is secured at all times when it is executing at any untrusted host. Our minimal implementation of the model with Aglets agent platform gives the first faithful picture of the happenings in the model. Finally, we also explain how the homomorphic property of ElGamal scheme can be integrated with our model for a Web-based application such as voting involving multiple agents.     

Development of an Adaptive EC Website With Online Identified Cognitive Styles of Anonymous Customers

This study developed an adaptive electronic commerce (EC) website based on users' cognitive styles without asking users to complete any evaluation forms. In this system, a multilayer feed forward neural network (MLFF) was designed to identify the cognitive styles of anonymous users by observing their browsing behavior. Then the system presented the adaptive interfaces, designed by investigating the relationships between users' cognitive styles and browsing behavior, to users based on the identified cognitive styles. Experiments were conducted to evaluate the effectiveness of the system. The experimental results verified the potential benefits of MLFF in identifying anonymous users' cognitive styles during browsing of EC applications and provided evidence that an adaptive EC website that presents product data consistent with the users' cognitive styles can be beneficial to one-to-one Internet marketing not only for users whose cognitive styles are known before browsing but also for anonymous users whose cognitive styles are identified during browsing.     

Mobile Underwater Sensor Networks for Protection and Security: Field Experience at the UAN11 Experiment

The EU‐funded project UAN (Underwater Acoustic Network) was aimed at conceiving, developing, and testing at sea an innovative and operational concept for integrating underwater and above‐water sensors in a unique communication system to protect offshore and coastline critical infrastructures. This work gives details on the underwater part of the project. It introduces a set of original security features and gives details on the integration of autonomous underwater vehicles (AUVs) as mobile nodes of the network and as surveillance assets, acoustically controlled by the command and control center to respond against intrusions. Field results are given of the final UAN project sea trial, UAN11, held in May 2011 in Norway. During the experimental activities, a UAN composed of four fixed nodes, two AUVs, and one mobile node mounted on the supporting research vessel was operated continuously and integrated into a global protection system. In this article, the communication performance of the network is reported in terms of round‐trip time, packet loss, and average delivery ratio. The major results of the experiment can be thus summarized: the implemented network structure was successful in continuously operating over five days with nodes seamlessly entering and exiting the network; the performance of the network varied greatly with fluctuations in the acoustic channel; the addition of security features induced a minor degradation in network performance with respect to channel variation; the AUVs were successfully controlled from a remote station through acoustic signals routed by the network. © 2013 Wiley Periodicals, Inc.