Miracle-dz/UniFAR-FTUs huggingface dataset:
H ∞ Fault Tolerant Control of WECS Based on the PWA Model

The main contribution of this paper is the development of H ∞ fault tolerant control for a wind energy conversion system (WECS) based on the stochastic piecewise affine (PWA) model. In this paper the normal and fault stochastic PWA models for WECS including multiple working points at different wind speeds are established. A reliable piecewise linear quadratic regulator state feedback is designed for the fault tolerant actuator and sensor. A sufficient condition for the existence of the passive fault tolerant controller is derived based on some linear matrix inequalities (LMIs). It is shown that the H ∞ fault tolerant controller of WECS can control the wind turbine exposed to multiple simultaneous sensor faults or actuator faults; that is, the reliability of wind turbines can be improved.
A random zoo: sloth, unicorn, and trx

Many applications require trustworthy generation of public random numbers. It is shown how this can be achieved using a hash function that is timed to be as slow as desired (sloth), while the correctness of the resulting hash can be verified quickly. It is shown how sloth can be used for uncontestable random number generation (unicorn), and how unicorn can be used for a new trustworthy random ellip­ tic curves service (trx) and random-sample
Evaluating Physiological Dynamics via Synchrosqueezing: Prediction of Ventilator Weaning

Oscillatory phenomena abound in many types of signals. Identifying the individual oscillatory components that constitute an observed biological signal leads to profound understanding about the biological system. The instantaneous frequency (IF), the amplitude modulation (AM), and their temporal variability are widely used to describe these oscillatory phenomena. In addition, the shape of the oscillatory pattern, repeated in time for an oscillatory component, is also an important characteristic that can be parametrized appropriately. These parameters can be viewed as phenomenological surrogates for the hidden dynamics of the biological system. To estimate jointly the IF, AM, and shape, this paper applies a novel and robust time-frequency analysis tool, referred to as the synchrosqueezing transform (SST). The usefulness of the model and SST are shown directly in predicting the clinical outcome of ventilator weaning. Compared with traditional respiration parameters, the breath-to-breath variability has been reported to be a better predictor of the outcome of the weaning procedure. So far, however, all these indices normally require at least 20 min of data acquisition to ensure predictive power. Moreover, the robustness of these indices to the inevitable noise is rarely discussed. We find that based on the proposed model, SST and only 3 min of respiration data, the ROC area under curve of the prediction accuracy is 0.76. The high predictive power that is achieved in the weaning problem, despite a shorter evaluation period, and the stability to noise suggest that other similar kinds of signal may likewise benefit from the proposed model and SST.
Waveform design for compressively sampled ultrawideband radar

Abstract. Compressive sensing makes it possible to recover sparse target scenes from under-sampled measurements when uncorrelated random-noise waveforms are used as probing signals. The mathematical theory behind this assertion is based on the fact that Toeplitz and circulant random matrices generated from independent identically distributed (i.i.d) Gaussian random sequences satisfy the restricted isometry property. In real systems, waveforms have smooth, nonideal autocorrelation functions, thereby degrading the performance of compressive sensing algorithms. Compressive sensing requires the system matrix to have particular properties. Incorporating prior information into the target scene either to enhance imaging or to mitigate nonidealities can result in system matrices that are not suitable for compressive sensing. We can overcome this problem by designing appropriate transmit waveforms. We extend the existing theory to incorporate such nonidealities into the analysis of compressive recovery. As an example we consider the problem of tailoring waveforms to image extended targets. Extended targets make the target scene denser, causing random transmit waveforms to be suboptimal for recovery. We propose to incorporate extended targets by considering them to be sparsely representable in redundant dictionaries. We demonstrate that a low complexity algorithm to optimize the transmit waveform leads to improved performance.
Flow-level performance analysis of random wireless network using stochastic Petri Nets

This paper combines stochastic geometry and Stochastic Petri Net (SPN) to analyze the flow-level performance of random wireless networks. The locations of BSs (Base Stations) follow a Poisson Point Process (PPP). UEs access the network when having data and leave when finished, and they are served by the closest BS. The transmission rate of UEs(User Equipments) can be derived using stochastic geometry. Since the state space of the queuing model grows exponentially with the number of cells, we use the model decomposition and iteration in SPNs to solve it. Besides, we can also derive the approximate steady-state solution and the flow-level performance in terms of mean delay and mean throughput of the system. Simulations are performed to verify the analytical results under different traffic loads. The results prove that the model is suitable for the performance evaluation of wireless network.
Specification of General Features of Scenarios and Robots for Benchmarking Through Competitions

RoCKIn is a EU-funded project aiming to foster scientific progress and innovation in cognitive systems and robotics through the design and implementation of competitions. An additional objective of RoCKIn is to increase public awareness of the current state-of-the-art in robotics and the innovation potential of robotics applications. From these objectives several requirements for the work performed in RoCKIn can be derived: • The RoCKIn competitions must start from convincing, easy-to-communicate user stories, that catch the attention of relevant stakeholders, the media, and the crowd. The user stories play the role of a mid-to long-term vision for a competition. Preferably , the user stories address economic, societal, or environmental problems. • The RoCKIn competitions must pose open scientific challenges of interest to sufficiently many researchers to attract existing and new teams of robotics researchers for participation in the competition. The competitions need to promise some suitable reward, such as recognition in the scientific community, publicity for a team's work, awards, or prize money, to justify the effort a team puts into the development of a competition entry. The competitions should be designed in such a way that they reward general, scientifically sound solutions to the challenge problems; such general solutions should score better than approaches that work only in narrowly defined contexts and are considred over-engineered. • The challenges motivating the RoCKIn competitions must be broken down into suitable intermediate goals that can be reached with a limited team effort until the next competition and the project duration. • The RoCKIn competitions must be well-defined and well-designed, with comprehensive rule books and instructions for the participants in order to guarantee a fair competition. • The RoCKIn competitions must integrate competitions with benchmarking in order to provide comprehensive feedback for the teams about the suitability of particular functional modules, their overall architecture, and system integration. This document takes the first steps towards the RoCKIn goals. After outlining our approach , we present several user stories for further discussion within the community. The main objectives of this document are to identify and document relevant scenario features and the tasks and functionalities subject for benchmarking in the competitions.
Constancy Analysis

A reference variable x is constant in a piece of code C if the execution of C does not modify the heap structure reachable from x. This information lets us infer purity of method arguments, an important ingredient during the analysis of programs dealing with dynamically allocated data structures. We define here an abstract domain expressing constancy as an abstract interpretation of concrete denotations. Then we define the induced abstract denotational semantics for Java-like programs and show how constancy information improves the precision of existing static analyses such as sharing, cyclicity and path-length.
Residual Stress Evaluation of Railway Wheels by X-Ray Diffraction and Finite Element Method

X-ray stress measurement is useful for determining, in a non-destructive manner, the surface stresses of engineered parts. However, the railway wheels cannot measure because this it is very large. So it should be measured using a scaled-down model. The problem is, however, how the stress release should be considered. In this analysis, the finite element method (FEM) was applied to estimate the initial stress state using stresses released after cutting a sample obtained by the X-ray method. Railway wheels were studied in this experiment. In the early 1990s, several railroads in the northeast of the U.S.A. experienced extensive cracking in the wheels of the commuter trains. Residual stresses in the hoop direction play an important role in mechanism fatigue damage. This paper will discuss about residual stress in the hoop direction in manufactured wheels. The results of FEM analysis and the X-ray diffraction method confirms that these methods can be used to evaluate the residual stress of the hoop direction. There is very good quantitative agreement between the simulated and measured stress distributions. It can be suggested that guessing guess stress release and the redistribution by the FEM analysis is possible. The residual hoop stress of the unused wheel presumed by this research has the residual stress of high compression in the wheel at the center of the rim up to 40mm depth. It is very safe because the residual stress state is compressive even when a crack occurs, and obstructs the crack’s progress. If a crack occurs by any chance, the stress state can obstruct the crack’s progress.
The capacitated multi-facility location–allocation problem with probabilistic customer location and demand: two hybrid meta-heuristic algorithms

A new mathematical model for the capacitated multi-facility location–allocation problem with probabilistic customers' locations and demands is developed in this article. The model is formulated into the frameworks of the expected value model (EVM) and the chance-constrained programming (CCP) based on two different distance measures. In order to solve the model, two hybrid intelligent algorithms are proposed, where the simplex algorithm and stochastic simulation are the bases for both algorithms. However, in the first algorithm, named SSGA, a special type of genetic algorithm is combined and in the second, SSVDO, a vibration-damping optimisation (VDO) algorithm is united. The Taguchi method is employed to tune the parameters of the two proposed algorithms. Finally, some numerical examples are given to illustrate the applications of the proposed methodologies and to compare their performances.
Choosing the set of rendezvous points in shared trees minimizing traffic concentration

In the current Internet there are two main types of intra-domain multicast routing protocols: dense mode and sparse mode. Dense mode protocols construct shortest path trees from a sender to receivers while sparse mode protocols construct shared trees rooted at a certain router, called core or RP (rendezvous point), to which all senders of a certain group send their packets in order to be transmitted to all receivers along such shared tree. These kinds of trees are well suited for wide-area networks, because we are sending information only to interested receivers and we maintain the same routing state for each group, independently of the number of senders, and only on the routers along the shared tree. While solving important scalability problems, such trees bring other drawbacks; mainly traffic concentration and delay. In current standards, PIM-SM (Estrin, Farinacci, Helmy, Thaler, Deering, Handley, Jacobson, Liu, Sharma, Wei, 1998) and CBT (Ballardie, 1997), no algorithms are specified to choose such RPs. In this paper, we present an approach to select the best set of RPs that minimizes traffic concentration while limiting the maximum delay.
Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

We study the combined effects of land surface conditions, atmospheric boundary layer dynamics and chemistry on the diurnal evolution of biogenic secondary organic aerosol in the atmospheric boundary layer, using a model that contains the essentials of all these components. First, we evaluate the model for a case study in Hyytiala, Finland, and find that it is able to satisfactorily reproduce the observed dynamics and gas-phase chemistry. We show that the exchange of organic aerosol between the free troposphere and the boundary layer (entrainment) must be taken into account in order to explain the observed diurnal cycle in organic aerosol (OA) concentration. An examination of the budgets of organic aerosol and terpene concentrations show that the former is dominated by entrainment, while the latter is mainly driven by emission and chemical transformation. We systematically investigate the role of the land surface, which governs both the surface energy balance partitioning and terpene emissions, and the large-scale atmospheric process of vertical subsidence. Entrainment is especially important for the dilution of organic aerosol concentrations under conditions of dry soils and low terpene emissions. Subsidence suppresses boundary layer growth while enhancing entrainment. Therefore, it influences the relationship between organic aerosol and terpene concentrations. Our findings indicate that the diurnal evolution of secondary organic aerosols (SOA) in the boundary layer is the result of coupled effects of the land surface, dynamics of the atmospheric boundary layer, chemistry, and free troposphere conditions. This has potentially some consequences for the design of both field campaigns and large-scale modeling studies.
Display of Surfaces from Volume Data Display of Surfaces from Volume Data

Vo/U11U relldering is a technique for visualizing sampled scalar fields of three spatial dimensions without fitting gcomeuic primitives 10 the data. A color and a partial transparency are computed for each dala sample, and images are Conned by blending together contributions made by samples projecting 10 the same pixel on the picture plane. Quantization and aliasing irtifacts are reduced by avoiding thresholding during dala classification and by carefully resampling the dala during projection. This thesis presents an image-order volume rendering algorithm, demonstraiCS ! hal it generates images of comparable quality to existing object-order algorithms, and offers several improvements. In particular, methods are presented for displaying isovalue con10ur surfaces and region boundary surfaces, forrendering mixtures of analytically defined geometry and sampled fields, and for adding shadows and textures. Tillu techniques for reducing rendering cost are also presented: hierarchical spatial enumeration, adaptive termination of ray aacing, and adaptive image sampling. Case studies from two applications arc given: medical imaging and molecular graphics.
Design mentoring based on design evolution analysis

The basic intuition underlying this work is that experienced designers are able to point out problematic patterns in the design structure of an artifact and questionable events and trends in its evolution. We believe that the very process of recognizing and reflecting upon specific interesting designs and design-evolution examples may help software developers acquire valuable design experience to complement their textbook knowledge. The objective of this work is to further develop JDEvAn, so that it becomes a software design-evolution mentor that can advise developers on a desired course of software maintenance and evolution, based on its assessment of the system's current design and the design rationale implicit in the system's evolution history. JDEvAn focuses on the logical view of object-oriented Java systems as the first design artifact to analyze.
Design and experimental implementation of easily detachable permanent magnet reluctance wheel for wall-climbing mobile robot

In this paper, we propose a new design of the permanent magnet(PM) reluctance wheel to make possible the robot to be attached to vertical plane and be in motion. In newly suggested design, PM is utilized to enhance the adhesive force during attachment, while electromagnet is introduced to weaken magnetic field and reduce the adhesive force for easier detachment of wheels from steel plates. To characterize the performance, 3-D finite element analysis is executed using commercial FE program. Experimental test is performed to compare with the result of the analysis. The results show that the adhesive force is reduced effectively by the electromagnet.
Monad transformers and modular interpreters

We show how a set of building blocks can be used to construct programming language interpreters, and present implementations of such building blocks capable of supporting many commonly known features, including simple expressions, three different function call mechanisms (call-by-name, call-by-value and lazy evaluation), references and assignment, nondeterminism, first-class continuations, and program tracing. The underlying mechanism of our system is monad transformers, a simple form of abstraction for introducing a wide range of computational behaviors, such as state, I/O, continuations, and exceptions. Our work is significant in the following respects. First, we have succeeded in designing a fully modular interpreter based on monad transformers that incudes features missing from Steele's, Espinosa's, and Wadler's earlier efforts. Second, we have found new ways to lift monad operations through monad transformers, in particular difficult cases not achieved in Moggi's original work. Third, we have demonstrated that interactions between features are reflected in liftings and that semantics can be changed by reordering monad transformers. Finally, we have implemented our interpreter in Gofer, whose constructor classes provide just the added power over Haskell's type classes to allow precise and convenient expression of our ideas. This implementation includes a method for constructing extensible unions and a form of subtyping that is interesting in its own right.
RE-SAMPLING METHODS IN REGRESSION : WHICH METHOD TO USE UNDER NON-NORMALITY ?

A variety of re-sampling methods have been developed to test the significance of regression coefficients in multiple regression (Levin & Robins, 1983; Freedman & Lane, 1983; Oja, 1987; Kennedy & Cade, 1996; ter Braak, 1992 and Manly, 1997). Some studies have compared the performance of some permutation methods when collinearity is present, when different sample sizes are used, when errors are normally and exponentially distributed and when there are few outliers present (Kennedy & Cade, 1996; Manly, 1997 and Anderson & Legendre, 1999). The main objective in this study is to assess the performance of a more comprehensive list of resampling methods in regression, in order to test the significance of coefficients in a multiple linear regression model with residuals displaying different levels of skewness and kurtosis.
Deformed metals – structure, recrystallisation and strength

Abstract It is shown how new discoveries and advanced experimental techniques in the last 25 years have led to paradigm shifts in the analysis of deformation and annealing structures of metals and in the way the strength of deformed samples is related to structural parameters. This is described in three sections: structural evolution by grain subdivision, recovery and recrystallisation and strength–structure relationships.
Qualitative Spatial Reasoning about Line Segments

Representing and reasoning about orientation information is an important aspect of qualitative spatial reasoning. We present a novel approach for dealing with intrinsic orientation information by specifying qualitative relations between oriented line segments, the simplest possible spatial entities being extended and having an intrinsic direction. We identify a set of 24 atomic relations which form a relation algebra and for which we compute relational compositions based on their algebraic semantics. Reasoning over the full algebra turns out to be NP-hard. Potential applications of the calculus are motivated with a small example which shows the reasoning capabilities of the dipole calculus using constraint-based reasoning methods.
An Active Constraint Method for Distributed Routing, and Power Control in Wireless Networks

Efficiently transmitting data in wireless networks requires joint optimization of routing, scheduling, and power control. As opposed to the universal dual decomposition we present a method that solves this optimization problem by fully exploiting our knowledge of active constraints. The method still maintains main requirements such as optimality, distributed implementation, multiple path routing and per-hop error performance. To reduce the complexity of the whole problem, we separate scheduling from routing and power control, including it instead in the constraint set of the joint optimization problem. Apart from the mathematical framework we introduce a routing and power control decomposition algorithm that uses the active constraint method, and we give further details on its distributed application. For verification, we apply the distributed RPCD algorithm to examples of wireless mesh backhaul networks with fixed nodes. Impressive convergence results indicate that the distributed RPCD algorithm calculates the optimum solution in one decomposition step only.
DYNAMIC SIGNATURE RECOGNITION FOR AUTOMATIC STUDENT AUTHENTICATION

Handwritten signatures are one of the most socially accepted biometric traits. Signatures are commonly used in financial and legal agreements since more than a century. In education, signatures are used for attendance control, either to lectures or exams, but not for (automatic) authentication. With the rapid deployment of dynamic signature recognition, this technology is ready to be used for student authentication. Also, the use of this technology can be extended to different administrative services within the education system, in order to add a higher security level to the traditional procedures of authentication (e.g., visually checking the face and/or signature on the person identity card). Nowadays, signatures can be easily captured by means of electronic devices (e.g. pen tablets, PDAs, grip pens, smartphones, etc.). For this reason, the popularity of this biometric trait is rapidly increasing in the last few years. Even more, signatures can be made using the finger as the writing tool on smartphones. In this paper, we analyse two scenarios for student authentication using their signatures: i) an office scenario with a high quality pen tablet specifically designed to acquire signatures (i.e., Wacom device), and ii) a mobile scenario where users sign on their smartphones with the finger improving this way the usability. For this experimental study we make use of e-BioSign database, which was captured using various modern pen tablet devices and smartphones. The database contains signatures from 70 users including students and educators, captured in two sessions in different days. The experiments on automatic authentication using dynamic signatures are conducted considering two different types of forgeries, namely: i) random forgeries (the case where an impostor uses his own signature claiming to be another person), and ii) skilled forgeries (where impostors imitate the signature of other persons).