Miracle-dz/UniFAR-FTUs huggingface dataset:
Sliding mode control and simulation of a hybrid Fuel-Cell Ultracapacitor power system

This paper deals with a robust control strategy for modern distributed generation systems made up of hybrid PEM (proton exchange membrane) Fuel Cell (FC) and Ultracapacitors (UCs) power system. Particularly, for future fuel cell a vehicle application is presented. Given the constraint of the FC dynamics and the complexity of the energy management, a second order sliding mode control (SMC) strategy is designed to improve the robustness and the performance of the system. This control strategy, based on frequency decomposition of the load specifications, uses a cascaded closed loop control. It takes into account the slow dynamics of FC and the state of charge (SOC) of the UCs. FC output power is determined according to the low frequency (LF) load requirement and the UC SOC. UCs value is determined according to the high frequency (HF) load requirement. Therefore, two voltage control loops are designed. The DC bus voltage is regulated by the UCs source using a classical proportional integrator (PI) controller. The UCs SOC voltage is regulated by the FC source using a sliding mode (SM) controller, which improves the global performance of the controlled system. An analysis of the simulation results is conducted using Matlab/Simulink software in order to verify the effectiveness of the proposed control strategy. It confirms that the developed model and its control strategy exhibit excellent performance.
Power system singularly perturbed discontinuous control

The synchronous generators have a natural different time scale dynamics. That is why for modeling and control design in such systems the methods of singular perturbations are widely used. In this paper the possibilities of sliding mode control design for synchronous generators are analyzed. With this aim the concept of singular perturbation is revised in order to use it for relay control system with a discontinuous slow-motion integral manifold. Obtained results are used for variable structure control of synchronous generator.
How little data is enough? Phase-diagram analysis of sparsity-regularized X-ray computed tomography

We introduce phase-diagram analysis, a standard tool in compressed sensing (CS), to the X-ray computed tomography (CT) community as a systematic method for determining how few projections suffice for accurate sparsity-regularized reconstruction. In CS, a phase diagram is a convenient way to study and express certain theoretical relations between sparsity and sufficient sampling. We adapt phase-diagram analysis for empirical use in X-ray CT for which the same theoretical results do not hold. We demonstrate in three case studies the potential of phase-diagram analysis for providing quantitative answers to questions of undersampling. First, we demonstrate that there are cases where X-ray CT empirically performs comparably with a near-optimal CS strategy, namely taking measurements with Gaussian sensing matrices. Second, we show that, in contrast to what might have been anticipated, taking randomized CT measurements does not lead to improved performance compared with standard structured sampling patterns. Finally, we show preliminary results of how well phase-diagram analysis can predict the sufficient number of projections for accurately reconstructing a large-scale image of a given sparsity by means of total-variation regularization.
Continents, supercontinents, mantle thermal mixing, and mantle thermal isolation: Theory, numerical simulations, and laboratory experiments

Super‐continental insulation refers to an increase in mantle temperature below a supercontinent due to the heat transfer inefficiency of thick, stagnant continental lithosphere relative to thinner, subducting oceanic lithosphere. We use thermal network theory, numerical simulations, and laboratory experiments to provide tighter physical insight into this process. We isolate two end‐member dynamic regimes. In the thermally well mixed regime the insulating effect of continental lithosphere can not cause a localized increase in mantle temperature due to the efficiency of lateral mixing in the mantle. In this regime the potential temperature of the entire mantle is higher than it would be without continents, the magnitude depending on the relative thickness of continental and oceanic lithosphere (i.e., the insulating effects of continental lithosphere are communicated to the entire mantle). Thermal mixing can be short circuited if subduction zones surround a supercontinent or if the convective flow pattern of the mantle becomes spatially fixed relative to a stationary supercontinent. This causes a transition to the thermal isolation regime: The potential temperature increases below a supercontinent whereas the potential temperature below oceanic domains drops such that the average temperature of the whole mantle remains constant. Transition into this regime would thus involve an increase in the suboceanic viscosity, due to local cooling, and consequently a decrease in the rate of oceanic lithosphere overturn. Transition out of this regime can involve the unleashing of flow driven by a large lateral temperature gradient, which will enhance global convective motions. Our analysis highlights that transitions between the two states, in either direction, will effect not only the mantle below a supercontinent but also the mantle below oceanic regions. This provides a larger set of predictions that can be compared to the geologic record to help determine if a hypothesized super‐continental thermal effect did or did not occur on our planet.
Optimal allocation of sensing duration among multiple primary channels in cognitive radio

In cognitive radio networks, allocation of the sensing duration is of critical importance for efficient spectrum sensing. Conventional optimization of sensing duration is limited in two primary channels as well as same constant thresholds for all the primary channels. In this paper, we consider multiple primary channels and formulate the problem of sensing duration allocation as a convex optimization with respect to both the sensing durations and detection thresholds. Then, based on Penalty method and Newton’s method, a searching algorithm is proposed to obtain the optimal solution. We show via simulation results that our scheme substantially improves the transmission opportunity of cognitive user compared with existing ones.
On a Web-Graph-Based Micronetwork Architecture for SoCs

Abstract The Network-on-Chip (NoC) concept has been identified as an attractive solution to the ever-increasing interconnect problem in complex System-on-Chip (SoC) designs. In this paper, we propose a highly scalable topology structure for NoC designs based on the web graph. This topology, named as Spidernet, is compared favourably to other five popular NoC topologies, including mesh, torus, fat tree, octagon, and spidergon in terms of node degree, network diameter, connection degree, average most short-circuit path, and average shortest wire length. We further propose a 2D layout design for Spidernet, and experiment results have confirmed its superiority over layouts derived from the above five competing topologies.
Collision avoidance in dynamic environments: An ICS-based solution and its comparative evaluation

This paper presents ICS-AVOID, a collision avoidance scheme based upon the concept of Inevitable Collision State (ICS), ie a state for which, no matter what the future trajectory of the robotic system is, a collision eventually occurs. By design, ICS-AVOID can handle dynamic environments since ICS do take into account the future behaviour of moving objects. ICS-AVOID is designed to keep the system away from ICS. By doing so, motion safety is guaranteed (by definition a robotic system in a non-ICS state has at least one collision-free trajectory that it can use). To demonstrate the efficiency of ICS-AVOID, it has been extensively compared with two state-of-the-art collision avoidance schemes: the first one is built upon the Dynamic Window approach and the second one on the Velocity Obstacle concept. The results obtained show that, when provided with the same amount of information about the future evolution of the environment, ICS-AVOID outperforms the other two schemes. The first reason for this has to do with the extent to which each collision avoidance scheme reasons about the future. The second reason has to do with the ability of each collision avoidance scheme to find a safe control if one exists. ICS-AVOID is the only one which is complete in this respect thanks to the concept of Safe Control Kernel.
A Peculiar Flaring Episode of Cygnus X-1

Recent monitoring of Cyg X-1 with the Rossi X-Ray Timing Explorer (RXTE) revealed a period of intense flaring, which started in 2000 October and lasted until 2001 March. The source exhibited some quite unusual behaviors during this period. The soft X-ray flux of the source went up and down 3 times on a timescale of about 1 month, as discovered by the All-Sky Monitor aboard RXTE, before finally returning to the normal level (of the hard state). The observed spectral and temporal X-ray properties of Cyg X-1 are mostly intermediate between the canonical hard and soft states. This is known previously for strong X-ray flares; however, we show that the source did enter a period that resembles, in many ways, a sustained soft state during the last of the three flares. We make detailed comparisons between this flare and the 1996 state transition in terms of the observed X-ray properties, such as the flux-hardness correlation, X-ray spectrum, and power density spectrum. We point out the similarities and differences, and discuss possible implications of the results on our understanding of the phenomena of flares and state transitions associated with Cyg X-1.
Genome Arrays for the Detection of Copy Number Variations in Idiopathic Mental Retardation, Idiopathic Generalized Epilepsy and Neuropsychiatric Disorders: Lessons for Diagnostic Workflow and Research

We review the contributions and limitations of genome-wide array-based identification of copy number variants (CNVs) in the clinical diagnostic evaluation of patients with mental retardation (MR) and other brain-related disorders. In unselected MR referrals a causative genomic gain or loss is detected in 14–18% of cases. Usually, such CNVs arise de novo, are not found in healthy subjects, and have a major impact on the phenotype by altering the dosage of multiple genes. This high diagnostic yield justifies array-based segmental aneuploidy screening as the initial genetic test in these patients. This also pertains to patients with autism (expected yield about 5–10% in nonsyndromic and 10–20% in syndromic patients) and schizophrenia (at least 5% yield). CNV studies in idiopathic generalized epilepsy, attention-deficit hyperactivity disorder, major depressive disorder and Tourette syndrome indicate that patients have, on average, a larger CNV burden as compared to controls. Collectively, the CNV studies suggest that a wide spectrum of disease-susceptibility variants exists, most of which are rare (<0.1%) and of variable and usually small effect. Notwithstanding, a rare CNV can have a major impact on the phenotype. Exome sequencing in MR and autism patients revealed de novo mutations in protein coding genes in 60 and 20% of cases, respectively. Therefore, it is likely that arrays will be supplanted by next-generation sequencing methods as the initial and perhaps ultimate diagnostic tool in patients with brain-related disorders, revealing both CNVs and mutations in a single test.
Using plant water use and drought response strategies and climate of origin to select shrubs for green roofs in dry and hot climates

The ideal species for green or vegetated roofs should have high water use after rainfall to maximise stormwater retention but also survive periods with low water availability in dry substrates. Shrubs have great potential for green roofs because they have higher rates of water use, and many species are also drought tolerant. However, not all shrub species will be suitable and there may be a trade-off between water use and drought tolerance. We conducted a glasshouse experiment to determine the possible trade-offs between shrub water use for stormwater management and their response to drought conditions. We selected 20 shrubs from a wide range of climate of origins, represented by heat moisture index (HMI) and mean annual precipitation (MAP). Under well-watered (WW) and water-deficit (WD) conditions, we assessed morphological responses to water availability; evapotranspiration rate (ET) and midday water potential (ΨMD) were used to evaluate species water use and drought response. In response to WD, all 20 shrubs adjusted their morphology and physiology. However, there were no species that simultaneously achieved high rates of water use (high ET) under WW and high drought tolerance (low ΨMD) under WD. Although some species which had high water use under WW conditions could avoid drought stress (high ΨMD). Water use was strongly related to plant biomass, total leaf area and leaf traits (SLA and LAR). Conversely, drought response (ΨMD) was not related to morphological traits. Species’ climate of origin was not related to drought response or water use. Drought avoiding shrubs (high ΨMD) could optimize rainfall reduction on green roofs. Water use was related to biomass, leaf area and leaf traits, thus these traits could be used to assist the selection of shrubs for stormwater mitigation on green roofs. The natural distribution of species was not related to their water use or drought
1 Trading Restrictions and Value : Marketability as an Option

We examine the usefulness of the option-based framework of Longstaff (1995) to estimate the effect of trading restrictions on the value of common stock. Longstaff’s fundamental insight is that marketability can be viewed as an option to sell an asset at the time of one’s choosing, so the value of marketability can be estimated using techniques from option pricing. Among other things, Longstaff’s model assumes a frictionless market where an investor with perfect timing ability will sell an asset and invest the proceeds to maximize the value of a portfolio. When there are restrictions on selling the asset, this investor is unable to optimize his/her wealth. Longstaff derives the resulting loss in value due to the restriction on trading, which varies with the risk of the asset. Analyzing a sample of 194 private placements of common stock in the United States from January 27, 2000 through March 27, 2008, we find empirical evidence that both volatility and trading restrictions are related to the percentage discount for on private placements. We categorize trading restrictions as one of two types: either liquidity or marketability. Using a Chow test to identify a structural break in the data, we find that the importance of marketability restrictions (e.g., the number of shares in the private placement relative to the total shares outstanding) is significant for private placements occurring in the last four and one half years of the sample period whereas, during the first part of the sample period, characteristics related liquidity (e.g., turnover and the bid-ask spread) are more important as determinants of discounts on private placements. 2 Trading Restrictions and Value: Marketability as an Option
A high-voltage-tolerant stimulator realized in the low-voltage CMOS process for cochlear implant

A biomedical stimulator with four high-voltagetolerant output channels, combined with on-chip positive high voltage generator, is proposed. For the purpose of integration with other circuit blocks into a system-on-chip (SoC) for cochlear implant biomedical applications, this design has been realized with the 1.8-V/3.3-V transistors in a 0.18-μm CMOS process. This stimulator only needs one single supply voltage of 1.8 V, but the maximum stimulation voltage can be as high as 7 V. The dynamic bias technique and stacked MOS configuration are used to implement this stimulator in the low-voltage CMOS process, without causing the issues of electrical overstress and gate-oxide reliability during circuit operation.
Counting Homomorphisms and Partition Functions

Homomorphisms between relational structures are not only fundamental mathematical objects, but are also of great importance in an applied computational context. Indeed, constraint satisfaction problems (CSPs), a wide class of algorithmic problems that occur in many different areas of computer science such as artificial intelligence or database theory, may be viewed as asking for homomorphisms between two relational structures [FedVar98]. In a logical setting, homomorphisms may be viewed as witnesses for positive primitive formulas in a relational language. As we shall see, homomorphisms, or more precisely the numbers of homomorphisms between two structures, are also related to a fundamental computational problem of statistical physics. In this article, we are concerned with the complexity of counting homomorphisms from a given structure A to a fixed structure B. Actually, we are mainly interested in a generalization of this problem to weighted homomorphisms (or partition functions). We almost exclusively focus on graphs. The first part of the article is a short survey of what is known about the problem. In the second part, we give a proof of a theorem due to Bulatov and the first author of this paper [BulGro05], which classifies the complexity of partition functions described by matrices with non-negative entries. The proof we give here is essentially the same as the original one, with a few shortcuts due to [Thu09], but it is phrased in a different, more graph theoretical language that may make it more accessible to most readers.
Contaminants from the transplant contribute to intimal hyperplasia associated with microvascular endothelial cell seeding.

OBJECTIVES seeding prosthetic grafts with fat-derived microvascular endothelial cells (MVEC) results not only in a non-thrombogenic EC layer, but also in intimal hyperplasia. Here we investigated incidence, composition, progression, and cause of this intimal hyperplasia. DESIGN EPTFE grafts with MVEC were implanted as carotid interpositions in six dogs with 1 month, and in three dogs with 4, 8 and 12 months follow-up. Grafts seeded without cells, implanted in the contralateral carotid, served as a control. In another three dogs labelled cells were seeded to investigate the contribution of the seeded cells (2-3 weeks). MATERIALS AND METHODS MVEC were isolated from the falciform ligament. Cells were pressure seeded on ePTFE grafts. Labelling was performed using retroviral gene transduction. The grafts were analysed with immunohistochemical techniques. RESULTS after 1 month, all patent non-seeded grafts (5/6) showed fibrin and platelet deposition, and all patent seeded grafts (5/6) were covered with a confluent endothelial monolayer on top of a multilayer of myofibroblasts, elastin and collagen. After long term follow-up, all non-seeded grafts were occluded, all patent seeded grafts (4 and 12 months) were covered with an EC-layer with intimal hyperplasia underneath. The thickness of the intima did not progress after 1 month. Transduced cells were found in the endothelial monolayer, hyperplastic intima and luminal part of the prosthesis. CONCLUSIONS MVEC seeding in dogs results in intimal hyperplasia in all patent grafts, which contains myofibroblasts. Contaminants from the transplant contribute to this intimal hyperplasia.
The University of Amsterdam at VideoCLEF 2008

The University of Amsterdam (UAms) team carried out the Vid2RSS classification task, the primary sub-task of the VideoCLEF track at CLEF 2008. This task involves the assignment of thematic category labels to dual language (Dutch/English) television episode videos. UAms chose to focus on exploiting archival metadata and speech transcripts generated by both the Dutch and English speech recognizers. Exploratory experimentation completed prior to the start of the task on external data motivated choosing a Support Vector Machine (SVM) with a linear kernel as the classifier. As a SVM toolbox to carry out the experiments, the Least Square-SVM (LS-SVM) toolbox was selected. Wikipedia was chosen as the source of the training data because it is multilingual and contains content with broad thematic coverage. The results of the experimentation showed that archival metadata improves performance of classification, but the addition of speech recognition transcripts in one or both languages does not yield performance gains. Although the overall performance of the classifiers was less than satisfactory, adequate performance was achieved in several classes, suggesting that there is concrete potential for future work to achieve performance improvements, especially if more suitable training data could be obtained.
PUCs: detecting transparent, passive untouched capacitive widgets on unmodified multi-touch displays

Capacitive multi-touch displays are not designed to detect passive objects placed on them-in fact, these systems usually contain filters to actively reject such touch data. We present a technical analysis of this problem and introduce Passive Untouched Capacitive Widgets (PUCs). Unlike previous approaches, PUCs do not require power, they can be made entirely transparent, they are detected reliably even when no user is touching them, and they do not require internal electrical or software modifications of the touch display or its driver. We show the results from testing PUCs on 17 different off-the-shelf capacitive touch display models, and provide initial technical design recommendations.
REVISITING SH-WAVE DATA USING LOVE-WAVE ANALYSIS

Although Love waves are widely analyzed in earthquake seismology, there is much less attention on utilizing Love waves than Rayleigh waves by the near-surface community. Unlike incident P and Sv waves, a plane SH wave for a series of horizontal layers refracts and reflects only SH waves, which makes the shallow SH-wave refraction method more popular to define shear (S)-wave velocity in near-surface geologic applications. For this reason, abundant SH-wave refraction data have been acquired and S-wave velocities have been determined using their first arrivals. If signals are recorded long enough, Love-wave energy can be clearly observed on SH-wave refraction data. Wave conversion may occur in an SH-wave refraction and Love-wave analysis only results in SH-wave velocities, which suggest that we may benefit from revisiting the existing SH-refraction data using multichannel analysis of Love waves (MALW). We used numerical modeling results and real-world examples to demonstrate three advantages of revisiting SH-wave data using the MALW method. Owing to a long geophone spread commonly used in SH-wave refraction survey, a sharp image of Love-wave energy can be generated, allowing better pickings for the phase velocities of Love waves. Because Love waves are independent of P-wave velocity, “mode crossing” in an image of Love-wave energy is less common than in Rayleigh-wave images. Fewer unknowns in the method MALW make dispersion curves of Love waves are simpler, which leads to more stable inversion of Love waves and reduces the degree of nonuniqueness.