Search

The research activity aims to evaluate the Mobile Laser Scanner mapping system's effectiveness and critical issues based on simultaneous localization and mapping (SLAM) called KAARTA Stencil. The research introduces a reflection on a series of test datasets resulting from the mobile system's application in an urban context taken as a case study and aimed at the representation and 3D modeling of architectural complexes.In detail, the metric accuracy of the proposed method was evaluated through a comparative analysis of the point cloud data through the evaluation of the surface deviation of the 3D point clouds based on the SLAM system and the data of static measurement systems, more precise to evaluate the accuracy of the proposed acquisition system. For each data were specified the possibilities of representation, the type of representation scale, and the possible manipulations and extractions of 2D profiles to design and analyze architectural elements through mobile systems.The analysis involves a breakdown of the problem of representation, identifying protocols that can be applicable at different levels and scales of reading aimed at the representation and discretization of parts and elements linked together in a hierarchical or interconnected relationship, outlining their criticality and potential.

Road traffic safety is one of the major challenges for the future of smart cities and transportation networks. Despite several solutions exist to reduce the number of fatalities and severe accidents happening daily in our roads, this reduction is smaller than expected and new methods and intelligent systems are needed. The emergency Call is an initiative of the European Commission aimed at providing rapid assistance to motorists thanks to the implementation of a unique emergency number. In this work, we study the problem of classifying the severity of accidents involving Powered Two Wheelers, by exploiting machine learning systems based on features that could be reasonably collected at the moment of the accident. An extended study on the set of features allows to identify the most important factors that enable to distinguish accident severity. The system we develop achieves around 90% of precision and recall on a large, publicly available corpus, using only a set of eleven features.

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) is a complex procedure with a relatively high rate of adverse events. Data on training of operators and fulfillment of quality indicators in Italy are scarce. The goal of this study was to assess the overall quality of ERCP in Italy compared to international standards. Patients and methods This was a prospective, observational study from different Italian centers performing ERCP. Operators answered a questionnaire, then recorded data on ERCPs over a 1-to 3-month period. Results Nineteen Italian centers participated in the study. The most common concern of operators about training was the lack of structured programs. Seven/19 centers routinely used conscious sedation for ERCP. Forty-one experienced operators and 21 trainees performed 766 ERCPs: a successful deep biliary cannulation in native-papilla patients was achieved in 95.1 % of cases; the post-ERCP pancreatitis (PEP) rate was 5.4 % in native-papilla patients; cholangitis rate was 1.0 %; bleeding and perforation occurred in 2.7 % and 0.4 % of the patients, respectively. Conclusions This study revealed that, overall, ERCP is performed in the participating Italian centers meeting good quality standards, but structured training and sedation practice are still subpar. The bleeding and perforation rate slightly exceeded the American Society of Gastrointestinal Endoscopy indicator targets but they are comparable to the reported rates from other international surveys.

Drones and unmanned vehicles in general are gaining more and more interest in the logistic sector, due to the potential economic advantages they can provide. In this paper we focus on optimizing the use of a drone in conjunction with a truck for urban deliveries, dealing with what is called the flying sidekick traveling salesman problem. There is a set of customers that it is possible to serve either by a truck or by a drone. The target is to minimize the total time required to complete deliveries to all the customers. In this paper we show how an effective and simple random restart local search heuristic algorithm can be derived from a known mixed integer programming model for the problem.

The recent emergence of consumer off-the-shelf embedded (IoT) devices and the rise of large-scale IoT botnets has dramatically increased the volume and sophistication of Linux malware observed in the wild. The security community has put a lot of effort to document these threats but analysts mostly rely on manual work, which makes it difficult to scale and hard to regularly maintain. Moreover, the vast amount of code reuse that characterizes IoT malware calls for an automated approach to detect similarities and identify the phylogenetic tree of each family. In this paper we present the largest measurement of IoT malware to date. We systematically reconstruct – through the use of binary code similarity – the lineage of IoT malware families, and track their relationships, evolution, and variants. We apply our technique on a dataset of more than 93k samples submitted to VirusTotal over a period of 3.5 years. We discuss the findings of our analysis and present several case studies to highlight the tangled relationships of IoT malware.

Background and study aims COVID-19 has dramatically impacted endoscopy practice because upper endoscopy procedures can be aerosol-generating. Most elective procedures have been rescheduled. Endoscopic retrograde cholangiopancreatography (ERCP) is frequently performed in emergency or urgent settings in which rescheduling is not possible. We evaluated the impact of the COVID-19 pandemic on ERCP in Italy during the SARS-CoV-2 lockdown, in areas with high incidence of COVID-19. Patients and methods We performed a retrospective survey of centers performing ERCP in high COVID-19 prevalence areas in Italy to collect information regarding clinical data from patients undergoing ERCP, staff, case-volume and organization of endoscopy units from March 8, 2020 to April 30, 2020. Results We collected data from 31 centers and 804 patients. All centers adopted a triage and/or screening protocol for SARS-CoV-2 and performed follow-up of patients 2 weeks after the procedure. ERCP case-volume was reduced by 44.1 % compared to the respective 2019 timeframe. Of the 804 patients undergoing ERCP, 22 (2.7 %) were positive for COVID-19. Adverse events occurred at a similar rate to previously published data. Of the patients, endoscopists, and nurses, 1.6 %, 11.7 %, and 4.9 %, respectively, tested positive for SARS-CoV-2 at follow up. Only 38.7 % of centers had access to a negative-pressure room for ERCP. Conclusion The case-volume reduction for ERCP during lockdown was lower than for other gastrointestinal endoscopy procedures. No definitive conclusions can be drawn about the percentage of SARS-CoV-2-positive patients and healthcare workers observed after ERCP. Appropriate triage and screening of patients and adherence to society recommendations are paramount.

The novel RNA betacoronavirus SARS-CoV-2 is driving great efforts in clinical and basic research and several studies of the epidemiology, risk factors, clinical and virological features of this infection are already available. However COVID-19 is a totally new pathological entity, and many gray areas regarding associated diseases still need to be elucidated, especially in the group of patients who suffer from preexistent gastrointestinal disease. The aim of this review is to summarize the published data on the correlation between chronic gastrointestinal disorders and COVID-19.

Clinical variables including hypertension could be linked with major bleeding events and death beyond vitamin K antagonist (warfarin) or direct oral anti-coagulants (DOACs) treatment strategy.Subgroup analysis of major bleeding (primary endpoint) associated with clinical variables, site of bleeding, ongoing antithrombotics, reversal treatment or blood transfusion, outcomes (secondary endpoints) was performed in patients with bleeding events submitted to hard 5:1 propensity-score matching for hypertension.Enrolled patients were 2,792 (mean age, 65.6 ± 19.9 years) during 2-year survey including 166,000 visits, of 200,000 inhabitants catchment area; 8,239 patients received warfarin and 3,797 DOACs. Hypertension account for 1,077 (39%) patients; major bleeding for 474 (17%); death for 29 (1%), and 72 (3%) on 1-month and 1-year, respectively. Hypertension, age, glucose, cancer, ischemic vascular disease, and CHA2D2VASc score were more likely to link with major bleeding. On multivariate analysis, only age (odds ratio [OR], 1.02; P0.001), CHA2DS2VASc score ≥ 2 (OR, 2.14; P = 0.001), and glucose (OR, 1.01; P = 0.005) were predictors of major bleeding. Kaplan-Meier analysis demonstrated patients with hypertension as compared with patients without showed 60% versus 20% death on 1-month (P0.001). Warfarin compared with DOACs was more likely to present with major bleeding (0.7% versus 0.2%; OR, 2.8; P = 0.005). Receiver operator characteristics analysis showed high value (0.61) of age and glucose over creatinine and systolic arterial pressure (P = NS).Four in 10 patients with major bleeding showed hypertension; of these 8 in 10 will die within 1 month. Warfarin compared with DOACs was more likely to present with major bleeding.

CO2 is the ultimate renewable carbon source on Earth and the essential C1 building block for carbohydrate biosynthesis in photosynthetic organisms. Modern synthetic chemistry is facing the key challenge of developing fundamental transformations, such as C-C bond formation, in a sustainable and efficient manner from renewable sources. In this Minireview, the most significant methods recently reported for CO2 fixation under transition metal-free conditions are summarized, organized into three different chapters according to the nature of the chemical transformation that forges the new C-C bond. The focus is on the mechanistic aspects of the different CO2 activation modes, with specific attention to those systems that operate under catalytic conditions.

Correspondences between key settings in Jean Rhys’s “Temps Perdi,” as suggested by analytics proffered by postmodern theories of space, suggest the Benjaminian notion of history as a perpetual state of emergency. Introduced in the three discrete sections of the story, these key settings are a house on the east coast of England during WWII, Vienna in the aftermath of WWI, and an unnamed Caribbean island (which the narrator visits between the wars). Further, the story’s key disabled characters, the narrator and a young Carib woman, point to Walter Benjamin’s notion of a revolutionary, “messianic” break with time, as suggested by analytics proffered by disability studies.

How to decide whether to engage in transactions with strangers? Whether we’re offering a ride, renting a room or apartment, buying or selling items, or even lending money, we need a degree of trust that the others will behave as they should. Systems like Airbnb, Uber, Blablacar, eBay and others handle this by creating systems where people initially start as untrusted, and they gain reputation over time by behaving well. Unfortunately, these systems are proprietary and siloed, meaning that all information about transactions becomes property of the company managing the systems, and that there are two types of barriers to entry: first, whenever new users enter a new system they will need to restart from scratch as untrusted, without the possibility of exploiting the reputation they gained elsewhere; second, new applications have a similar cold-start problem: young systems, where nobody has reputation yet, are difficult to kickstart.

This paper proposes a methodology to assess the impact of shared light electric vehicles in urban areas. The proposed approach consists of the comparison between the emissions and costs of travels carried out by traditional cars fueled by gasoline and those performed by shared light electric vehicles in six European cities (Bari, Berlin, Genoa, Malaga, Rome and Trikala) located in four different European countries (Italy, Germany, Spain and Greece). Based on the number of kilometers traveled and a set of conversion factors, the environmental impact and the cost of fuel/electricity are assessed for the two transport modes. Furthermore, the paper proposes a methodology to create a geographical scaled up scenario that allows to evaluate emissions and costs in case of an increased use of shared electric vehicles. The data analyzed revealed that the travel time of L-category electric vehicles might be longer compared to cars. Furthermore, by replacing car trips with L-category electric vehicles, $CO _{2}$ emissions could decrease of more than 70% in one year, thus reducing about 6,082 kg of $CO _{2}$ emissions.

The European Union's (EU) General Data Protection Regulation (GDPR), in effect since May 2018, enforces strict limitations on handling users' personal data, hence impacting their activity tracking on the Web. In this study, we perform an evaluation of the tracking performed in 2,000 high-traffic websites, hosted both inside and outside of the EU. We evaluate both the information presented to users and the actual tracking implemented through cookies; we find that the GDPR has impacted website behavior in a truly global way, both directly and indirectly: USA-based websites behave similarly to EU-based ones, while third-party opt-out services reduce the amount of tracking even for websites which do not put any effort in respecting the new law. On the other hand, we find that tracking remains ubiquitous. In particular, we found cookies that can identify users when visiting more than 90% of the websites in our dataset - and we also encountered a large number of websites that present deceiving information, making it it very difficult, if at all possible, for users to avoid being tracked.

Understanding users' perceptions of suspected computer-security problems can help us tailor technology to better protect users. To this end, we conducted a field study of users' perceptions using 189,272 problem descriptions sent to the customer-support desk of a large anti-virus vendor from 2015 to 2018. Using qualitative methods, we analyzed 650 problem descriptions to study the security issues users faced and the symptoms that led users to their own diagnoses. Subsequently, we investigated to what extent and for what types of issues user diagnoses matched those of experts. We found, for example, that users and experts were likely to agree for most issues, but not for attacks (e.g., malware infections), for which they agreed only in 44% of the cases. Our findings inform several user-security improvements, including how to automate interactions with users to resolve issues and to better communicate issues to users.

We study the mixed capacitated general routing problem (MCGRP) in which a fleet of capacitated vehicles has to serve a set of requests by traversing a mixed weighted graph. The requests may be located on nodes, edges, and arcs. The problem has theoretical interest because it is a generalization of the capacitated vehicle routing problem (CVRP), the capacitated arc routing problem (CARP), and the general routing problem. It is also of great practical interest since it is often a more accurate model for real-world cases than its widely studied specializations, particularly for so-called street routing applications. Examples are urban waste collection, snow removal, and newspaper delivery. We propose a new iterated local search metaheuristic for the problem that also includes vital mechanisms from adaptive large neighborhood search combined with further intensification through local search. The method utilizes selected, tailored, and novel local search and large neighborhood search operators, as well as a new local search strategy. Computational experiments show that the proposed metaheuristic is highly effective on five published benchmarks for the MCGRP. The metaheuristic yields excellent results also on seven standard CARP data sets, and good results on four well-known CVRP benchmarks, including improvement of the best known upper bound for one instance.

This work aims to study drivers' route choices using a dataset of low frequency GPS coordinates to identify travels' trajectories. The sample consists of 89 drivers who performed 42 thousand paths in the province of Reggio Emilia, in Italy, during the seventeen considered months. Four attributes that may be important for the driver are identified and four optimal alternative paths are created based on the selected objectives to evaluate route choice behaviour. The comparison between the characteristics of the paths allows to conclude that drivers select routes that are overall longer than their optimal alternatives but that allow for higher speeds. Furthermore the statistical analysis of drivers' route choices in macroareas evidences that drivers have different behaviours depending on the geography of the territory. Specifically, there is higher heterogeneity of route choices in the plain areas compared to the mountains. In the second part of this work, clusters of repetitive travels are identified and a Geographical Route Directness Index is proposed to identify the areas of the province where the deviation from the shortest alternative path is higher. The analysis shows that, among groups of repetitive travels, the value of the index is higher along the ring road of the city of Reggio Emilia and there is a strong negative correlation between the frequency the driver selects the longer alternative that allow for higher speed, and the number of additional kilometres the same driver has to travel.

The paper through an excursus on the technological development of virtual fruition systems, intends to reflect on the methods of communication and dissemination of cultural heritage, taking as a reference part of the results of research recently conducted on some case studies. The museum, configured in its new immaterial form and no longer as an exclusively physical place, amplifies the availability of space open to visitors, revolutionizing its role as cultural mediator in the extension of a potential connective that increases the dynamics of social development. The present research was aimed at programming a methodological protocol for the documentation and the virtualization of museum assets, collections and architectural heritage of tourist interest, based on a new approach to fruition of the space and the work of art in it contained.

First Online 30 August 2019, Despite the hype, the effective implementation of Open Science is hindered by several cultural and technical barriers. Researchers embraced digital science, use “digital laboratories” (e.g. research infrastructures, thematic services) to conduct their research and publish research data, but practices and tools are still far from achieving the expectations of transparency and reproducibility of Open Science. The places where science is performed and the places where science is published are still regarded as different realms. Publishing is still a post-experimental, tedious, manual process, too often limited to articles, in some contexts semantically linked to datasets, rarely to software, generally disregarding digital representations of experiments. In this work we present the OpenAIRE Research Community Dashboard (RCD), designed to overcome some of these barriers for a given research community, minimizing the technical efforts and without renouncing any of the community services or practices. The RCD flanks digital laboratories of research communities with scholarly communication tools for discovering and publishing interlinked scientific products such as literature, datasets, and software. The benefits of the RCD are show-cased by means of two real-case scenarios: the European Marine Science community and the European Plate Observing System (EPOS) research infrastructure., This work is partly funded by the OpenAIRE-Advance H2020 project (grant number: 777541; call: H2020-EINFRA-2017) and the OpenAIREConnect H2020 project (grant number: 731011; call: H2020-EINFRA-2016-1). Moreover, we would like to thank our colleagues Michele Manunta, Francesco Casu, and Claudio De Luca (Institute for the Electromagnetic Sensing of the Environment, CNR, Italy) for their work on the EPOS infrastructure RCD; and Stephane Pesant (University of Bremen, Germany) his work on the European Marine Science RCD.

The use of genetic markers located on the X chromosome has seen a significant increase in the last years and their utility has been well studied. This paper describes the software FamLinkX, freely available at http://www.famlink.se, implementing a new algorithm for likelihood computations accounting for linkage, linkage disequilibrium and mutations. It is obvious that such software is sought for among forensic users as more and more X-chromosomal markers become available. We provide some simulated examples demonstrating the utility of the implementation as well as its application in forensic casework. Though algebraic derivations are generally unfeasible, the paper outlines some theoretical considerations and provides a discussion on the validation of the software. The focus of this paper is to compare the software to existing methods in a forensic setting, perform a validation study as well as to provide an idea of the discriminatory power for X-chromosomal markers.

We study a real-world distribution problem arising in the automotive field in which cars, trucks, and other vehicles have to be loaded onto auto-carriers and then delivered to dealers. The solution of the problem involves both the computation of the routing of the auto-carriers along the road network and the determination of a feasible loading for each carrier. We solve the problem by means of an iterated local search algorithm that makes use of several inner local search strategies for the routing part and mathematical modeling and enumeration techniques for the loading part. Extensive computational results on real-world instances show that good savings on the total cost can be obtained within small computational efforts.

Natural gas is the cleanest fossil fuel since it emits the lowest amount of other remains after being burned. Over the years, natural gas usage has increased significantly. Accurate forecasting is crucial for maintaining gas supplies, transportation and network stability. This paper presents two methodologies to identify the optimal configuration o parameters of a Neural Network (NN) to forecast the next 24 h of gas flow for each node of a large gas network.

The fleet size and mix vehicle routing problem with time windows (FSMVRPTW) is the problem of determining, at the same time, the composition and the routing of a fleet of heterogeneous vehicles aimed to serve a given set of customers. The routing problem requires us to design a set of minimum-cost routes originating and terminating at a central depot and serving customers with known demands, within given time windows. This paper develops a constructive insertion heuristic and a metaheuristic algorithm for FSMVRPTW. Extensive computational experiments on benchmark instances show that the proposed method is robust and efficient, and outperforms the previously published results.

The Australian minerals processing and extractive metallurgy industries are responsible for about 20% of Australia’s total greenhouse gas (GHG) emissions. This article reviews the potential applications of concentrated solar thermal (CST) energy in the Australian minerals processing industry to reduce this impact. Integrating CST energy into these industries would reduce their reliance upon conventional fossil fuels and reduce GHG emissions. As CST technologies become more widely deployed and cheaper, and as fuel prices rise, CST energy will progressively become more competitive with conventional energy sources. Some of the applications identified in this article are expected to become commercially competitive provided the costs for pollution abatement and GHG mitigation are internalized. The areas of potential for CST integration identified in this study can be classed as either medium/low-temperature or high-temperature applications. The most promising medium/low-grade applications are electricity generation and low grade heating of liquids. Electricity generation with CST energy—also known as concentrated solar power—has the greatest potential to reduce GHG emissions out of all the potential applications identified because of the 24/7 dispatchability when integrated with thermal storage. High-temperature applications identified include the thermal decomposition of alumina and the calcination of limestone to lime in solar kilns, as well as the production of syngas from natural gas and carbonaceous materials for various metallurgical processes including nickel and direct reduced iron production. Hybridization and integration with thermal storage could enable CST to sustain these energy-intensive metallurgical processes continuously. High-temperature applications are the focus of this paper.

Direct coal liquefaction (DCL) is a process for converting coal to synthetic oils, which can be refined to make transportation fuels. Residue from this process contains inorganic material such as mineral matter originating from the coal and catalysts, and organic matter such as unconverted coal, heavy oils, pre-asphaltenes and asphaltenes. The conversion of these DCL residues to lighter, high-value products is an important step in helping to make this technology both commercially viable and environmentally acceptable. This paper provides an overview of the physico-chemical characteristics and processing options available for coal liquefaction residues and compares and contrasts them to those of petroleum residues. Residue properties vary considerably, since they are highly dependent on feed coal, process configuration and operating conditions. Determination of composition and structural parameters of products derived from residue conversion can help determine their stability, coking and solvent hydrogen donating ability. Thermal conversion processes such as visbreaking and gasification offer the greatest promise for handling these heavy materials. The conversion chemistry, reactivity and kinetics of residue gasification are not well-understood but are important in optimising hydrogen production for the process. The literature has been comprehensively reviewed to provide characteristics and properties of residues and their potential for conversion. In addition, the potential for producing high-value carbon products from residues is briefly discussed.

Size-based scheduling with aging has been recognized as an effective approach to guarantee fairness and near-optimal system response times. We present HFSP, a scheduler introducing this technique to a real, multi-server, complex, and widely used system such as Hadoop. Size-based scheduling requires a priori job size information, which is not available in Hadoop: HFSP builds such knowledge by estimating it on-line during job execution. Our experiments, which are based on realistic workloads generated via a standard benchmarking suite, pinpoint at a significant decrease in system response times with respect to the widely used Hadoop Fair scheduler, without impacting the fairness of the scheduler, and show that HFSP is largely tolerant to job size estimation errors.

Most websites, services, and applications have come to rely on Internet services (e.g., DNS, CDN, email, WWW, etc.) offered by third parties. Although employing such services generally improves reliability and cost-effectiveness, it also creates dependencies on service providers, which may expose websites to additional risks, such as DDoS attacks or cascading failures. As cloud services are becoming more popular, an increasing percentage of the overall Internet ecosystem relies on a decreasing number of highly popular services. In our general effort to assess the security risk for a given entity, and motivated by the effects of recent service disruptions, we perform a large-scale analysis of passive and active DNS datasets including more than 2.5 trillion queries in order to discover the dependencies between websites and Internet services. In this paper, we present the findings of our DNS dataset analysis, and attempt to expose important insights about the ecosystem of dependencies. To further understand the nature of dependencies, we perform graph-theoretic analysis on the dependency graph and propose support power, a novel power measure that can quantify the amount of dependence websites and other services have on a particular service. Our DNS analysis findings reveal that the current service ecosystem is dominated by a handful of popular service providers---with Amazon being the leader, by far---whose popularity is steadily increasing. These findings are further supported by our graph analysis results, which also reveals a set of less-popular services that many (regional) websites depend on.

Mobile phones have an unprecedented rate of penetration across the world. Such devices produce a large amount of data that have been used on different domains. In this work, we make use of mobile calls to monitor the presence of individuals region by region. Traditionally, this activity has been conducted by means of censuses and surveys. Nowadays, technologies open new possibilities to analyse the individual calling behaviour to determine the amount of residents, commuters and visitors moving in an area. To this end, in this paper we provide a clustering technique completely unsupervised able to cluster data by exploring an arbitrary similarity metric. We make use of such technique, and we define metric to analyse mobile calls and individual profiles. The approach provides better population estimation with respect to state of the art when results are compared with real census data and greatly improves the execution time of a previous work of some of the authors of this paper. The scalability and flexibility of the proposed framework enables novel scenarios for the characterization of people by means of data derived from mobile users, ranging from the nearly real-time estimation of presences to the definition of complex, uncommon user archetypes.

The central task of a Security Incident and Event Manager (SIEM) or Managed Security Service Provider (MSSP) is to detect security incidents on the basis of tens of thousands of event types coming from many kinds of security products. We present Smoke Detector, which processes trillions of security events with the Random Walk with Restart (RWR) algorithm, inferring high order relationships between known security incidents and imperfect secondary security events (smoke) to find undiscovered security incidents (fire). By finding previously undetected incidents, Smoke Detector's RWR algorithm is able to increase the MSSP's critical incident count by 19% with a 1.3% FP rate. Perhaps equally importantly, our approach offers significant benefits beyond increased incident detection: (1) It provides a robust approach for leveraging Big Data sensor nets to increase adversarial resistance of protected networks; (2) Our event-scoring techniques enable efficient discovery of primary indicators of compromise; (3) Our confidence scores provide intuition and tuning capabilities for Smoke Detector's discovered security incidents, aiding incident display and response.

This thesis deals with the Electrohydraulic Power Steering system for road vehicles, using electronic pressure control valves. With an ever increasing demand for safer vehicles and fewer traffic ac ...

Development of efficient thermal energy storage (TES) technology is key to successful utilisation of solar energy for high temperature (>420 °C) applications. Phase change materials (PCMs) have been identified as having advantages over sensible heat storage media. An important component of TES development is therefore selection of PCM media. Given the huge and growing number of new materials currently available today (>160,000) finding a suitable material is a complicated and time consuming process. This paper demonstrates the use of a materials selection software based on a multi-objective optimisation methodology to identify potential PCM media for TES. In addition an environmental audit function of the software is used to evaluate the environmental credentials of PCMs—in an analyses not previously reported in the literature. Metals such as Al, Mg, Si and Zn and their eutectics 88Al–12Si and 60Al–34Mg–6Zn were found to be highly suitable as PCMs for the duty considered (steam from 400–750 °C). Their properties, heat of fusion, thermal conductivity, etc. have advantages over traditional molten salts—with 88Al–12Si showing the best environmental performance as well. The heat transfer effectiveness of this alloy was also evaluated by the e-NTU method and favourably compared to a HiTech salt using a heat exchanger geometry.

Direct coal liquefaction process typically produces mixed oils (60%) and gases (15%). The remainder is a high-boiling viscous residue that contains oils, asphaltenes, unreacted coal, mineral matter and potentially valuable liquefaction catalyst. Effective separation of the components of the residue stream is important to the economic and environmental performance of the process. Solid-liquid separation technologies, such as filtration, hydrocyclones, centrifugation, critical solvent deashing and distillation have been reviewed in relation to their use in coal liquefaction processes. Individual operations used have not been completely satisfactory, and a better overall result is obtained when they are used in combination. © 2012 Canadian Society for Chemical Engineering.

The problem of designing new keyboard layouts able to improve the typing speed of an average message has been widely considered in the literature of the Ergonomics domain. Empirical tests with users and simple optimization criteria have been used to propose new solutions. On the contrary, very few papers in Operations Research have addressed this optimization problem. In this paper we firstly resume the most relevant problems in keyboard design, enlightening the related Ergonomics aspects. Then we concentrate on keyboards that must be used with a single finger or stylus, like that of portable data assistant, smartphones and other small devices. We show that the underlying optimization problem is a generalization of the well-known quadratic assignment problem (QAP). We recall some of the most effective metaheuristic algorithms for QAP and we propose some non-trivial extensions to the keyboard design problem. We compare the new algorithms through computational experiments with instances obtained from word lists of the English, French, Italian and Spanish languages. We provide on the web benchmark instances for each language and the best solutions we obtained.

In this paper, we deal with the Bike sharing Rebalancing Problem (BRP), which is the problem of driving a fleet of capacitated vehicles to redistribute bicycles among the stations of a bike sharing system. We tackle the BRP with a destroy and repair metaheuristic algorithm, which makes use of a new effective constructive heuristic and of several local search procedures. The computational effort required for the neighborhood explorations is reduced by means of a set of techniques based on the properties of feasible BRP solutions. In addition, the algorithm is adapted to solve the one-commodity Pickup and Delivery Vehicle Routing Problem with maximum Duration (1-PDVRPD), which is the variant of the BRP in which a maximum duration is imposed on each route.Extensive computational results on instances from the literature and on newly-collected large-size real-world instances are provided. Our destroy and repair algorithm compares very well with respect to an exact branch-and-cut algorithm and a previous metaheuristic algorithm in the literature. It improves several best-known solutions, providing high quality results on both problem variants. HighlightsWe present a new metaheuristic algorithm for BRP and 1-PDVRPD.We introduce new properties and speed-up techniques for local search operators.We present a new Savings based heuristic for BRP and 1-PDVRPD.We present a new time-packing inequality to be used in a B&C for 1-PDVRPD.Strong results improvement and new optima for BRP and 1-PDVRPD have been obtained.

In traffic engineering, different assumptions on user behaviour are adopted in order to model the traffic flow propagation on the transport network. This paper deals with the classical hypothesis that drivers use the shortest possible path for their trip, pointing out the error related to using such approximation in practice, in particular in the context of dynamic origin-destination (OD) matrix estimation. If this problem is already well known in the literature, only few works are available, which provide quantitative and empirical analysis of the discrepancy between observed and modelled route sets and choices. This is mainly related to the complexity of collecting suitable data: to analyse route choice in a systematic way, it is necessary to have observations for a large period of time, since observing trajectories for the single user on a specific day could not be enough. Information is required for several days in order to analyse the repetitiveness and understand which elements influence this choice. In this work the use of the real shortest path for a congested network is evaluated, showing the differences between what we model and what users do. Results show that there is a systematic difference between the best possible choice and the actual choice, and that users clearly consider route travel time reliability in their choice process.

The vehicle routing problem with simultaneous distribution and collection (VRPSDC) is the variation of the capacitated vehicle routing problem that arises when the distribution of goods from a depot to a set of customers and the collection of waste from the customers to the depot must be performed by the same vehicles of limited capacity and the customers can be visited in any order. We study how the branch-and-price technique can be applied to the solution of this problem and in particular we compare two different ways of solving the pricing subproblem: exact dynamic programming and state space relaxation. By applying a bidirectional search we experimentally prove its effectiveness in solving the subproblem. We also devise suitable branching strategies for both the exact and the relaxed approach and we report on an extensive set of computational experiments on benchmark instances with both simple and composite demands.

T*(2) multislice multiecho cardiac MR allows quantification of the segmental distribution of myocardial iron overload. This study aimed to determine if there were preferential patterns of myocardial iron overload in thalassemia major. Five hundred twenty-three thalassemia major patients underwent cardiac MR. Three short-axis views of the left ventricle were acquired and analyzed using a 16-segment standardized model. The T*(2) value on each segment was calculated, as well as the global value. Four main circumferential regions (anterior, septal, inferior, and lateral) were defined. Significant segmental variability was found in the 229 patients with significant myocardial iron overload (global T*(2)

LENZ, BROOKE. John Fowles: Visionary and Voyeur. Amsterdam and New York: Rodopi, 2008. 251 pp. $78.00. The introductory chapter of John Fowles: Visionary and Voyeur is titled "Voyeurism and Other Visual Pleasures" and does, at its end, address voyeurism in Fowles's fiction. The bulk of the chapter, however, is dedicated to an argument about the two ways in which feminist standpoint theory can be usefully applied to Fowles. The first way is as a reading practice, in the sense that an understanding of standpoint theory encourages a more "collaborative" approach to reading (19). The second is as a way to grasp the precise nature of Fowles's feminism, which is Lenz's primary concern in her study. With regard to reading practices, a greater than typical collaboration with author is needed in the case of Fowles, because, according to Lenz, he does not appear to have written with the female reader in mind, and his fictions inscribe, ambiguously, both feminist and patriarchal views. This requires the feminist reader to prise, patiently, the feminism out of them: "Through the use of standpoint methodology, the relationship between critic and text (and critic and author) can become less oppositional and categorical, and more collaborative" (19). Standpoint theory is useful in describing Fowles's feminism in the literal sense that his writing can be read as a gradual realization of feminist standpoint epistemology in narrative form. In Lenz's view, Fowles reaches a definite turning point by the time of writing Daniel Martin (1977), consolidates that step forward in his two subsequent books (The Ebony Tower and Mantissa), and arrives at a fully realized "standpoint" narrative in his last novel, A Maggot (1985): "In advocating [the central female character's] practice of multi-perspectival dissent, A Maggot demonstrates Fowles's truly feminist commitment to the transformative potential of situated knowledges" (221). Few readers of Fowles would disagree with the contention that his writing shows voyeuristic elements, and the many reasons why Lenz believes Fowles should be considered a voyeur are addressed in the final pages of her introductory chapter. She states that his "narrative style" is "steeped in cinematic conventions" (33); that "characters do a great deal of watching" (35); that even "reader[s] are made to watch in a unique way" (35); and that, also with regard to readers, "pleasure results from the tension between mystery and increasing fullness of vision" (as this increasing understanding is delivered over the course of Fowles's storylines) (35). Lenz notes also that Fowles's fiction is "enraptured with transgression and coercion" and that a "fascination with the erotic and with the seduction of the tease ... determines the viewing practices of this texts" (36). As this list of quite diverse textual qualities and readerly experiences suggests, we are invited to understand voyeurism loosely as a power dynamic, evoked by Lenz to address mostly, if not exclusively, a number of coercive authorial and erotic effects. Although the voyeuristic qualities Lenz discerns in Fowles's work are explored in her study, her primary interest revolves around reading Fowles in relation to feminist standpoint theory. This approach pays off well in her readings of Daniel Martin and A Maggot, two of the later fictions that Lenz's introduction indeed argues are the best expressions of standpoint narratives. We are inclined to agree with Lenz that Fowles arrives, in his later fiction, at more convincing representations of his characters and their gendered interrelations by virtue of greater attention to what is usefully approached as "situated knowledges." An abiding feature of Fowles's fiction is the way that central female characters help male protagonists to grow and understand themselves. …

One of the main activities in highway construction is earthwork, which is a complex process involving excavation, transportation, and filling of large quantities of different earth material types. Earthwork operations are costly and undergo several constraints because of the fact that they have large environmental and social effects on the areas surrounding the construction site. Using mathematical models to produce a minimum-cost earthwork plan that satisfies all constraints is thus of great significance for enhancing the productivity of the overall construction project. This paper presents an earthwork optimization system on the basis of the use of linear programming that operates in a novel two-phase approach. In the first phase, an aggregate model determines the feasibility of the overall project, whereas in the second phase, disaggregate models determine the actual flows of each material. The two-phase quantitative method for earthwork optimization developed in this paper includes all feature...

This paper introduces a rolling horizon algorithm to plan the delivery of vehicles to automotive dealers by a heterogeneous fleet of auto-carriers. The problem consists in scheduling the deliveries over a multiple-day planning horizon during which requests for transportation arrive dynamically. In addition, the routing of the auto-carriers must take into account constraints related to the loading of the vehicles on the carriers. The objective is to minimize the sum of traveled distances, fixed costs for auto-carrier operation, service costs, and penalties for late deliveries. The problem is solved by a heuristic that first selects the vehicles to be delivered in the next few days and then optimizes the deliveries by an iterated local search procedure. A branch-and-bound search is used to check the feasibility of the loading. To handle the dynamic nature of the problem, the complete algorithm is applied repeatedly in a rolling horizon framework. Computational results on data from a major European logistics service provider show that the heuristic is fast and yields significant improvements compared to the sequential solution of independent daily problems.

In steering-related active safety systems, active steering is a key component. Active steering refers to the possibility to control the road wheel angle or the required torque to turn the wheels by means of an electronic signal. Due to the high axle loads in heavy vehicles, hydraulic power is needed to assist the driver in turning the wheels. One solution to realize active steering is, then, to use electronically controlled valves that are of closed-center type. This means that the assistance pressure, or force, can be set to any feasible value and still benefit from the high power density of fluid power systems. A closed-center solution also implies that a significant reduction in fuel consumption is possible. This paper investigates such an electrohydraulic power steering system, and a comparison with the original system is also made. The findings have shown that while a high response of the pressure control loop is desired for a good steering feel, instability might occur at higher steering wheel torque levels. This has effectively been shown and explained by simulation and hardware-in-the-loop simulation, together with linear analysis. For any desired boost curve, the response of the pressure control loop must be designed to preserve stability over the entire working range.

User connectivity patterns in network applications are known to be heterogeneous, and to follow periodic (daily and weekly) patterns. In many cases, the regularity and the correlation of those patterns is problematic: for network applications, many connected users create peaks of demand; in contrast, in peer-to-peer scenarios, having few users online results in a scarcity of available resources. On the other hand, since connectivity patterns exhibit a periodic behavior, they are to some extent predictable. This work shows how this can be exploited to anticipate future user connectivity and to have applications proactively responding to it. We evaluate the probability that any given user will be online at any given time, and assess the prediction on six-month availability traces from three different Internet applications. Building upon this, we show how our probabilistic approach makes it easy to evaluate and optimize the performance in a number of diverse network application models, and to use them to optimize systems. In particular, we show how this approach can be used in distributed hash tables, friend-to-friend storage, and cache pre-loading for social networks, resulting in substantial gains in data availability and system efficiency at negligible costs., Comment: Accepted for publication in IEEE/ACM Transactions on Networking

There is a clear trend in the vehicle industry to implement more safetyrelated functions, where the focus is on active safety systems and today the steering system is also involved. Steering-relate ...

Objective The present in vitro study was designed to ascertain whether the presence of sinuses of Valsalva in the aortic root were able to regulate the valve effective orifice area and modulate the gradient across the valve independently from root compliance. Methods Four different root configurations were prepared. Of the 4, 2 were silicon configurations with the same compliance, 1 with and 1 without sinuses of Valsalva, in which a 25-mm Solo stentless aortic valve was sutured inside. The other 2 configurations were obtained by substituting the upper part of the root with a straight Dacron graft or with a Valsalva graft in a remodeling fashion to reproduce the surgical situation. All roots were mounted in a pulse duplicator to measure the pressure decrease across the valve and effective orifice area at different cardiac outputs. Results With increasing cardiac output up to 7 L/min, an increase in the pressure decrease across the valve was evident in both configurations without sinuses of Valsalva (7.90 ± 1.7 and 11 mm Hg ± 0.1 mm Hg, respectively) but not in those with sinuses (2.87 ± 0.5 and 2.42 mm Hg ± 0.5 mm Hg). Similarly, with increasing cardiac output, the effective orifice area increased significantly only in the roots with sinuses (5.13 ± 0.5 and 5.47 ± 0.5 vs 3.06 ± 0.3 and 2.50 cm 2 ± 0.02 cm 2 , respectively). Conclusions When the cardiac output is increased to greater than the resting physiologic values, the presence of sinuses of Valsalva, independently of root compliance, prevents an increase in the pressure decrease across the valve by way of an increase of the effective orifice area.