Estimating burned area for Tropical Africa for the year 1990 with the NOAA-NASA Pathfinder AVHRR 8 km land dataset

The international scientific community recognizes the long-term monitoring of biomass burning as important for global climate change, vegetation disturbance and land cover change research on the Earth's surface. Although high spatial resolution satellite images may offer a more detailed view of land surfaces, their limited area coverage and temporal sampling have restricted their use to local research rather than global monitoring. Low spatial resolution images provide an invaluable source for the detection of burned areas in vegetation cover (scars) at global scale along time. However, the automated burned area mapping algorithm applicable at continental or global scale must be sufficiently robust to accommodate the global variation in burned scar signals. Here, the estimation of the percentage of a pixel area affected by a fire is crucial. In a first step, an empirical method is used which is based on a function between the change in Normalized Difference Vegetation Index (NDVI) and the surface area affected by fire. Next, a new statistical method, based on the Monte Carlo algorithm, is applied to compute probabilities of burned pixels percentages in different neighbourhood conditions.     

Involving users in the wild—Participatory product development in and with online communities

In its traditional stance, participatory design (PD) is centred on certain work/application settings and is concerned with the involvement of representative users from these contexts. Nevertheless, current web technologies enable new forms of distributed participation which might allow PD processes to be implemented in a broader and flexible way, but may at the same time raise new issues in relation to participation. In this paper, we report on a Participatory Product Development project, using social technologies, where new issues were raised—a large population of heterogeneous and globally distributed users; a range of personal and institutional purposes, and the use of these technologies in a largely untested environment. We will reflect on insights that we gathered by through observation of and participation in a software development process driven and influenced by members of an existing online community. By means of participatory observation, analysis of the use of online tools and through semi- structured interviews we identified issues around different notions of timeliness and of process structures that are related to different roles, responsibilities and levels of experience. Our results indicate that the involvement of heterogeneous users in such a context needs to be handled carefully, for the reasons we set out. The role of user representatives acting for a broader online community can become crucial when managing heterogeneity, formulating acceptable compromises and- perhaps most crucially- dealing with different professional and ‘hobbyist’ worldviews. Additionally, we found that the use of standard web technologies only partly support online participation processes. PD ‘in the wild’ needs to be better embedded in use situations and environments (e.g., by linking discussion and design space, using feedback tools, continuous reflection of the current state of development) rather than refining participatory design as a meta-process separate from use.     

The active disturbance rejection control of the rotating disk–beam system with boundary input disturbances

This paper deals with the stabilisation of the rotating disk–beam system, where the control ends of beam and disk are suffered from disturbances, respectively. The active disturbance rejection control (ADRC) approach is adopted in investigation. The disturbances are first estimated by the extended state observers, and the observer-based feedback control laws are then designed to cancel the disturbances. When the angular velocity of the disk is less than the square root of the first nature frequency of the beam, it is shown that the feedback control laws are robust to the external disturbances, that is, the vibration of the beam can be suppressed while the disk rotating with a desired angular velocity in presence of the disturbances. Finally, the simulation results are provided to illustrate the effectiveness of ADRC approach.     

Enhancement of the consistency of MODIS thin cirrus with cloud phase by adding 1.6 μm reflectance

Optically thin cirrus derived from the Moderate‐resolution Imaging Spectroradiometer (MODIS) instrument is examined in connection with its cloud phase (ice crystal or liquid droplet) for quasi‐single layer thin cirrus (either single‐layer thin cirrus or thin cirrus overlying low‐level thin clouds) over water surface conditions. Analysing 142 MODIS data samples during the period 1–16 March 2000, it is found that only about 20% of MODIS thin cirrus having a total‐column cloud optical depth less than 2.0 was detected as ice phase. In the present study, MODIS cloud phase datasets are newly reproduced by adding the 1.6 μm reflectance to an existing infrared trispectral algorithm of MODIS which used the 8.7, 11 and 12 mm bands. The percentage of ice phase in the thin cirrus is estimated at about 80% when new cloud phase is incorporated. The increase is found for all regions, in particular in mid‐latitudes.     

Improving the performance of pipelined query processing with skipping—and its comparison to document-wise partitioning

Web search engines need to provide high throughput and short query latency. Recent results show that pipelined query processing over a term-wise partitioned inverted index may have superior throughput. However, the query processing latency and scalability with respect to the collections size are the main challenges associated with this method. In this paper, we evaluate the effect of inverted index skipping on the performance of pipelined query processing. Further, we introduce a novel idea of using Max-Score pruning within pipelined query processing and a new term assignment heuristic, partitioning by Max-Score. Our current results indicate a significant improvement over the state-of-the-art approach and lead to several further optimizations which include dynamic load balancing, intra-query concurrent processing and a hybrid combination between pipelined and non-pipelined execution. Lastly, we show how the state of term-wise partitioning relates to the industry standard document-wise partitioning. Even though there are situations pipelined query processing is advantegous, document-wise partitioning is still the road to follow.     

Learning figures with the Hausdorff metric by fractals—towards computable binary classification

We present learning of figures, nonempty compact sets in Euclidean space, based on Gold’s learning model aiming at a computable foundation for binary classification of multivariate data. Encoding real vectors with no numerical error requires infinite sequences, resulting in a gap between each real vector and its discretized representation used for the actual machine learning process. Our motivation is to provide an analysis of machine learning problems that explicitly tackles this aspect which has been glossed over in the literature on binary classification as well as in other machine learning tasks such as regression and clustering. In this paper, we amalgamate two processes: discretization and binary classification. Each learning target, the set of real vectors classified as positive, is treated as a figure. A learning machine receives discretized vectors as input data and outputs a sequence of discrete representations of the target figure in the form of self-similar sets, known as fractals. The generalization error of each output is measured by the Hausdorff metric. Using this learning framework, we reveal a hierarchy of learnable classes under various learning criteria in the track of traditional analysis based on Gold’s learning model, and show a mathematical connection between machine learning and fractal geometry by measuring the complexity of learning using the Hausdorff dimension and the VC dimension. Moreover, we analyze computability aspects of learning of figures using the framework of Type-2 Theory of Effectivity (TTE).     

The active disturbance rejection and sliding mode control approach to the stabilization of the Euler–Bernoulli beam equation with boundary input disturbance

In this paper, we are concerned with the boundary feedback stabilization of a one-dimensional Euler–Bernoulli beam equation with the external disturbance flowing to the control end. The active disturbance rejection control (ADRC) and sliding mode control (SMC) are adopted in investigation. By the ADRC approach, the disturbance is estimated through an extended state observer and canceled online by the approximated one in the closed-loop. It is shown that the external disturbance can be attenuated in the sense that the resulting closed-loop system under the extended state feedback tends to any arbitrary given vicinity of zero as the time goes to infinity. In the second part, we use the SMC to reject the disturbance by removing the condition in ADRC that the derivative of the disturbance is supposed to be bounded. The existence and uniqueness of the solution for the closed-loop via SMC are proved, and the monotonicity of the “reaching condition” is presented without the differentiation of the sliding mode function, for which it may not always exist for the weak solution of the closed-loop system. The numerical simulations validate the effectiveness of both methods.     

On the evaluation of statistical characteristics at the output signal of non-linear control systems excited by a random input with a normal distribution†

We treat the problem of evaluating the statistical characteristics at the output signal of automatic control systems containing non-linear elements with zero memory excited by a random input with a normal distribution.

In this paper, in order to analyse the statistical characteristics we propose the statistical linearization technique determined by the condition that the variances at the output signal of a true nonlinear control system and of an equivalent linearized one are equal. The several examples are presented to illustrate the proposed method     

The good enough revolution—the role of aesthetics in user experiences with digital artefacts

Technological development takes place at a rapid pace, and in recent years it has led to a growing output of artefacts and services with digital content, where availability and low price seem to be the main parameters for success. This trend has been labelled the ‘good enough’ revolution and has highlighted contemporary parameters for technological development. The present article presents this trend as a design movement that is characterised by introducing a new functionalism and challenging common perceptions that have emerged as a result of the twentieth-century design story about ‘high quality’ and ‘added value’ in product development. In addition, the article introduces the concept of aesthetics as the basis for a discussion about user experiences in contemporary digital artefacts, and argues that the good enough movement calls for a new understanding of aesthetics that springs from the role of digital artefacts in the user's social life and plays a role in relation to technologically oriented design development.     

Teaching about the electricity supply industry—The development and evaluation of a computer based teaching package for schools

This paper describes the development of a computer based teaching package for use at upper secondary school level. The project was funded by Understanding Electricity, which is the educational service of the Electricity Council. The principles of electricity supply are integral to several subject areas in the school curriculum. The purpose of this package is firstly to provide well-resourced teaching material to cover these curriculum needs and secondly to provide an industrial context in which to apply the technical skills acquired in individual subject disciplines. The package is based on a computer simulation that enables the user to experience the problems of running an electricity supply system. The use of the computer in this way enables a powerful investigative approach to be adopted in the classroom.The paper begins by discussing the background to joint industry/education projects and the procedural models that have emerged. It continues by presenting the project history, the development team model used and the educational concepts of electricity supply that provide the background to the computer simulation. Attention is drawn to the ways in which the finished package matches the industrial resource material to curriculum needs.Teachers were involved from the beginning, both in the development of the computer software and in the production of curriculum material. They also undertook the design of investigations in specific subject areas—economics, physics, mathematics and geography. This paper presents the results of field trials and discusses the problems of evaluating and marketing educational material.Although the detail of this paper deals specifically with educational material developed for the Electricity Council, the principles discussed have significance for approaches to the production of educational software generally.     

Structural comparison among the 2013–2017 avian influenza A H5N6 hemagglutinin proteins: A computational study with epidemiological implications

Avian influenza viruses easily spread allowing viral re-assortment to simply occur which in-turn increases the potential for a pandemic. A novel 2013 H5N6 influenza strain was detected among the avian population and was reported to continuously evolve, however, this was never structurally demonstrated. Here, we elucidated the putative structural evolution of the novel H5N6 influenza strain. Throughout this study, we analyzed 2013–2017 H5N6 HA protein models. Model quality was first verified before further analyses and structural comparison was made using superimposition. We found that Leu was inserted at position 129₁ among the 2013–2015 models while Leu was not inserted among the 2016–2017 models. Moreover, presence of Leu at position 129₁ shifts residue E126₁ by 159.6° affecting nearby residues which may explain the difference between the 2013–2015 and 2016–2017 HA structural groups. Similarly, we believe that our results would support the hypothesis that the current H5N6 strain is still continuously evolving.     

The study of dual COX-2/5-LOX inhibitors by using electronic-topological approach based on data on the ligand–receptor interactions

Structural and electronic factors influencing selective inhibition of cyclooxygenase-2 and 5-lipoxygenase (COX-2/5-LOX) were studied by using Electronic-Topological Method combined with Neural Networks (ETM–NN), molecular docking, and Density Functional Theory (DFT) in a large set of molecules. The results of the ETM–NN calculations allowed for the selection of pharmacophoric molecular fragments, which could be taken as a basis for a system capable of predicting the COX-2/5-LOX inhibitory activity. For the more effective extraction of the pharmacophoric molecular fragments, docking of molecules into the active sites of the two enzymes was carried out to get data on the ligand–receptor interaction. To make an assessment of these interactions, stabilization energies were calculated by using Natural Bond Orbital (NBO) analysis. Docking and data on the electronic structures of active sites of enzymes helped to reveal effectively the peculiarities of the ligand–receptor binding. The system for the selective COX-2/5-LOX inhibitory activity prediction that has been developed as the result of the ETM–NN study recognized correctly 93% of compounds as highly active ones. Thus, this system can be successfully used for carrying out computer screening and synthesis of potent inhibitors of COX-2/5-LOX with diverse molecular skeletons.     

Identification of the transition state for fast reactions: The trapping of hydroxyl and methyl radicals by DMPO—A DFT approach

Up to date, attempts to locate the transition state (TS) for the trapping reaction between OH and DMPO have been unsuccessful, and the lack of molecular mechanisms by which OH binds to the spin-trap constitutes a question still unsolved. Herein, we have taken a step forward on this task by describing the theoretical TS for the trapping of OH and CH₃ by DMPO and the intrinsic reaction coordinates. This work aims to provide new understandings on the molecular orbital (MO) interactions that rule these reaction paths. Besides we assessed the degree of involvement of weak interactions and the charge transfer (CT) phenomenon involved in such interactions. Regarding the trapping of OH, the beginning of the reaction would be ruled by weak interactions to then give way to stronger MO interactions conducive to the formation of the TS. For CH₃, the reaction is, instead, early ruled by significant MO interactions, and a relatively small contribution in the weak interactions range. At the TS, both reactions share the formation of an antibonding orbital responsible for hosting the unpaired electron, and two bonding orbitals between the radical and the spin-trap. Additionally, the charge is transferred primarily from DMPO to OH through β orbitals, while for CH₃, the CT occurs in both directions, so that while DMPO behaves like an α-acceptor/β-donor, CH₃ acts as a β-acceptor/α-donor. Finally, we provide evidence showing that the resultant theoretical models are in agreement with the hyperfine coupling constants as obtained from biological-ESR spin trapping experiments.