Miracle-dz/UniFAR-FTUs huggingface dataset:
Data-Driven Optimal Control Using Perron-Frobenius Operator

In this paper, we propose a data-driven approach for control of nonlinear dynamical systems. The proposed data-driven approach relies on transfer Koopman and Perron-Frobenius (P-F) operators for linear representation and control of such systems. Systematic model-based frameworks involving linear transfer P-F operator were proposed for almost everywhere stability analysis and control design of a nonlinear dynamical system in previous works [1-3]. Lyapunov measure can be used as a tool to provide linear programming-based computational framework for stability analysis and almost everywhere stabilizing control design of a nonlinear system. In this paper, we show that those frameworks can be extended to a data-driven setting, where the finite dimensional approximation of linear transfer P-F operator and stabilizing feedback controller can be obtained from time-series data. We exploit the positivity and Markov property of these operators and their finite-dimensional approximation to provide {\it linear programming} based approach for designing an optimally stabilizing feedback controller.
Rapid Core Formation in Terrestrial Planets by Percolative Flow: In-Situ Imaging of Metallic Melt Migration Under High Pressure/Temperature Conditions

Core formation has left a lasting geochemical signature on the Earth. In order to constrain the composition of the Earth we must fully understand the processes by which newly formed Earth, and the bodies which accreted to it, differentiated. Percolation of iron-rich melt through solid silicate has been invoked as a mechanism for differentiation and core formation in terrestrial bodies in the early solar system. However, to date the contribution of percolation to core formation cannot be assessed due to the absence of data on Fe-rich melt migration velocities. Here we use a novel experimental design to investigate textural changes in an analogue system, Au melt in polycrystalline h-BN, under the high pressure/temperature (PT) of core formation at 3 GPa, relevant to core formation in the early solar system. Using a combination of high resolution, in-situ X-ray tomography and fast 2-D radiographic imaging, we obtain the first direct data on melt migration velocities at high PT. Melt migration is highly variable and episodic, driven by variations in differential pressure during melt migration and matrix compaction. Smaller scale melt processes, representing migration of melt along pre-existing melt networks, give comparatively fast velocities of 0.6-60 µms-1. Ex-situ experiments are used to compare melt networks in analogue systems to Fe-rich melt in silicates. Two competing processes for melt migration are percolation of melt along grain boundaries, and hydraulic fracturing induced by melt injection. Typically, both processes are noted in experimental and natural systems, although the relative importance of each mechanism is variable. Using a simple model for melt flow through a porous media, migration velocities determined here account for full differentiation of Earth-sized bodies within 101 to 103 Myr, for submicron diameter melt bands, or within a few Myr or micron-sized melt bands. This is consistent with rapid timescales inferred from geochemistry for core formation in planetesimals, implying that percolation may have had an important contribution to core differentiation in the Earth.
Design Guideline for Developing Safe Systems that Apply Electricity to the Human Body

The human body has unique electrical characteristics. These characteristics have been investigated in various studies in human-computer interaction (HCI) and related research fields. Such studies include applications for using the body as a conductive lead for transmission or electric field sensing and activating human muscles or organs. However, electricity is not completely safe for the human body; therefore, to avoid harming users, careful consideration is essential when developing such devices. The knowledge required for such consideration is spread throughout a large number research fields, and it can be difficult for researchers in the HCI field to comprehend all of them. The purpose of this article is to support researchers in developing systems that apply electricity to the human body and to serve as a basis for further research. This article reviews previous research pertaining to HCI in which users come into contact with electricity. In addition, considerations of how and where this type of research can be expanded, along with guidelines grounded in other fields for designing systems safely and addressing ethical concerns, are presented. An understanding of the field and of the related safety issues will enhance the understanding of limitations and potential and can clarify the design space.
Social Resistances and the Creation of Another Way of Thinking in the Peripheral “Self-Constructed Popular Neighborhoods”: Examples from Mexico, Argentina, and Bolivia

This study refers to urban social movements, creative social resistances, and the collectives that are emerging today in “self-constructed popular neighborhoods” (“barrios de auto-construccion popular” in Latin-American, Spanish bibliography; “quartiers d’auto-construction populaire” in French bibliography and “self-help housing” in Anglophone bibliography), with a special focus on the new characteristics of these movements and the poetics of their daily practices. Firstly, a cartographic approach is explained through the concept of eco-landscapes; a qualitative analysis follows based on interviews and a review of the secondary literature. In particular, this research focuses on cases of movements and collectives in villas in South Greater Buenos Aires, barrios of Ciudad Nezahualcoyotl in the Metropolitan Area of Mexico City, and barrios of El Alto in the Metropolitan Area of La Paz. It shows that the poetics of creative resistances question the symbolic power of territorial stigmatization.
Functional Connectivity and Genetic Profile of a “Double-Cortex”-Like Malformation

Laminar heterotopia is a rare condition consisting in an extra layer of gray matter under properly migrated cortex; it configures an atypical presentation of periventricular nodular heterotopia (PNH) or a double cortex (DC) syndrome. We conducted an original functional MRI (fMRI) analysis in a drug-resistant epilepsy patient with “double-cortex”-like malformation to reveal her functional connectivity (FC) as well as a wide genetic analysis to identify possible genetic substrates. Heterotopias were segmented into region of interests (ROIs), whose voxel-wise FC was compared to that of (i) its normally migrated counterpart, (ii) its contralateral homologous, and (iii) those of 30 age-matched healthy controls. Extensive genetic analysis was conducted to screen cortical malformations-associated genes. Compared to healthy controls, both laminar heterotopias and the overlying cortex showed significant reduction of FC with the contralateral hemisphere. Two heterozygous variants of uncertain clinical significance were found, involving autosomal recessive disease-causing genes, FAT4 and COL18A1. This first FC analysis of a unique case of “double-cortex”-like malformation revealed a hemispheric connectivity segregation both in the laminar cortex as in the correctly migrated one, with a new pattern of genes’ mutations. Our study suggests the altered FC could have an electrophysiological and functional impact on large-scale brain networks, and the involvement of not yet identified genes in “double-cortex”-like malformation with a possible role of rare variants in recessive genes as pathogenic cofactors.
Design of terahertz sensors based on metasurfaces for fungal infection detection

The proposed work is about the design of sensors in the terahertz band, for the detection of thin films, and microorganisms, in particular fungi. Firstly, a deep simulation study of the behavior of some metasurfaces and its performance as sensors, using the commercial software CST Microwave Studio has been performed. Three kind of structures have been studied: first, a cross-dipole structure, then a hole array structure, and finally, a densely packed frequency selective surfaces in two different configurations (transmission and reflection). Parametric studies have been carried out varying the concentration of microorganisms or the film thickness deposited on each structure. The optimization of structures with better prospects for biosensing applications have been undertaken. Once the statistical study of these structures was finished, an experimental study of the most promising ones has been carried out, using the instrumentation available in the TERALAB. The results demonstrate the promising perspectives of THz sensing based on metasurfaces.
EM Gun Bore Life Experiments at Naval Research Laboratory

The Naval Research Laboratory (NRL) performs basic and applied research on high power railguns as part of the US Navy EM Launcher program. The understanding of damage mechanisms as a function of armature and barrel materials, launch parameters, and bore geometry is of primary interest to the development of a viable high power railgun. Research is performed on a 6-m, 1.5-MJ railgun located at NRL. Barrel studies utilize in situ diagnostics coupled with detailed ex situ analysis of rail materials to provide clues to the conditions present during launch. Results are compared with coupled 3-D electromagnetic and mechanical finite element analysis models of railgun operation. Results of several experiments on rail wear will be discussed.
Grouper: A Compact, Streamable Triangle Mesh Data Structure.

We present Grouper: an all-in-one compact file format, random-access data structure, and streamable representation for large triangle meshes. Similarly to the recently published SQuad representation, Grouper represents the geometry and connectivity of a mesh by grouping vertices and triangles into fixed-size records, most of which store two adjacent triangles and a shared vertex. Unlike SQuad, however, Grouper interleaves geometry with connectivity and uses a new connectivity representation to ensure that vertices and triangles can be stored in a coherent order that enables memory-efficient sequential stream processing. We present a linear-time construction algorithm that allows streaming out Grouper meshes using a small memory footprint while preserving the initial ordering of vertices. As part of this construction, we show how the problem of assigning vertices and triangles to groups reduces to a well-known NP-hard optimization problem, and present a simple yet effective heuristic solution that performs well in practice. Our array-based Grouper representation also doubles as a triangle mesh data structure that allows direct access to vertices and triangles. Storing only about two integer references per triangle, Grouper answers both incidence and adjacency queries in amortized constant time. Our compact representation enables data-parallel processing on multicore computers, instant partitioning and fast transmission for distributed processing, as well as efficient out-of-core access.
Epochs : 10 Epochs : 20 Epochs : 40 Epochs : 80 Epochs : 160 Epochs : 320

Given recent deep learning results that demonstrate the ability to effectively optimize high-dimensional non-convex functions with gradient descent optimization on GPUs, we ask in this paper whether symbolic gradient optimization tools such as Tensorflow can be effective for planning in hybrid (mixed discrete and continuous) nonlinear domains with high dimensional state and action spaces? To this end, we demonstrate that hybrid planning with Tensorflow and RMSProp gradient descent is competitive with mixed integer linear program (MILP) based optimization on piecewise linear planning domains (where we can compute optimal solutions) and substantially outperforms state-of-the-art interior point methods for nonlinear planning domains. Furthermore, we remark that Tensorflow is highly scalable, converging to a strong plan on a large-scale concurrent domain with a total of 576,000 continuous action parameters distributed over a horizon of 96 time steps and 100 parallel instances in only 4 minutes. We provide a number of insights that clarify such strong performance including observations that despite long horizons, RMSProp avoids both the vanishing and exploding gradient problems. Together these results suggest a new frontier for highly scalable planning in nonlinear hybrid domains by leveraging GPUs and the power of recent advances in gradient descent with highly optimized toolkits like Tensorflow.
Origen y aportaciones de la perspectiva ontosemiótica de investigación en didáctica de la matemática

El enfoque ontosemiotico de investigacion en didactica de la matematica (EOS) fue iniciado en la Universidad de Granada a principios de los noventa, como resultado de la interaccion de investigadores de dicha universidad con los desarrollos teoricos de la didactica de la matematica iniciados en Francia. Asi mismo, la diversidad de teorias usadas para estudiar los procesos de ensenanza y aprendizaje de las matematicas llevo a la conviccion de la necesidad y utilidad de tratar de clarificarlas, y compararlas. La estrategia de articulacion de las teorias y el desarrollo de la aproximacion ontosemiotica ha sido fruto del analisis racional de los fundamentos, cuestiones y metodos de diversos marcos teoricos existentes y de la aplicacion de las herramientas teoricas que se fueron produciendo en trabajos experimentales. En esta ponencia se presenta una sintesis historica del origen y desarrollo del EOS, sus principales aportaciones para la investigacion en didactica de las matematicas, el estado actual a nivel internacional y algunas reflexiones sobre su potencial futuro.
Mining version histories to guide software changes

We apply data mining to version histories in order to guide programmers along related changes: "Programmers who changed these functions also changed. ". Given a set of existing changes, such rules (a) suggest and predict likely further changes, (b) show up item coupling that is indetectable by program analysis, and (c) prevent errors due to incomplete changes. After an initial change, our ROSE prototype can correctly predict 26% of further files to be changed - and 15% of the precise functions or variables. The topmost three suggestions contain a correct location with a likelihood of 64%.
Analyzing R&D Knowledge Flows In The Flat World

Abstract Previous research has firmly established the importance of informal social networks in facilitating knowledge flows in research and development (R&D) settings. However, the explosion of Web technologies in recent years have ’flattened’ the planet and dramatically altered our understanding of what constitutes a social network. Despite this, current research has neglected to examine how Web technologies have impacted knowledge flows in R&D. To address this research gap, we revisit the highly influential technological gatekeeper theory. Drawing on social network analysis (SNA) and interview evidence from a medical devices R&D group, we find that the gatekeeper role is still vital, but no longer needs to be performed by a single individual. Instead, the modern R&D group can keep abreast of the latest technological advances through a combination of Web-enabled internal and external communication specialists. A unique contribution this paper makes to the IT-enabled social network literature is the development of an updated conceptual framework of how the gatekeeper role is performed in the modern R&D group.
Geological education for undergraduate civil engineers

Summary Problems exist in the teaching of geology to undergraduate civil engineers. These may be attributed not only to the inherent nature of the subject material but also to the attitude of qualified civil engineers. The scepticism expressed by some civil engineers is ascribed to the partial replacement of geology by soil mechanics, the specialist nature of geotechnical work within the construction industry, the non-quantitative nature of geology, and the lack of geologists employed in civil engineering. Difficulties are experienced in teaching because of the limited time available and the necessity for students to acquire enough basic knowledge to enable them to appreciate the applications of the science to civil engineering. An outline teaching schedule is suggested that allows for some 'pure' geology as well as engineering geology. Field work, project work and reference to case histories are important if the student is to appreciate the relevance of the subject material. With this treatment geology may be a unifying as opposed to a peripheral subject in civil engineering courses.
The camp model for entrepreneurship teaching

Moving people from their normal work place or school environment to a camp site can be an efficient means for team building, creativity training and innovation boosting purposes. The camp model is increasingly used in the entrepreneurship education field as a supplement to classroom teaching. Some camps focus at the generation of ideas while others focus at the turning of ideas into concepts and rudimentary plans. By means of in-depth studies of three quite different camps, all demonstrating convincing results, the learning outcomes, pedagogies and principles for camps are identified and discussed.
Whole Genome Comparisons Suggest Random Distribution of Mycobacterium ulcerans Genotypes in a Buruli Ulcer Endemic Region of Ghana

Efforts to control the spread of Buruli ulcer – an emerging ulcerative skin infection caused by Mycobacterium ulcerans - have been hampered by our poor understanding of reservoirs and transmission. To help address this issue, we compared whole genomes from 18 clinical M. ulcerans isolates from a 30km2 region within the Asante Akim North District, Ashanti region, Ghana, with 15 other M. ulcerans isolates from elsewhere in Ghana and the surrounding countries of Ivory Coast, Togo, Benin and Nigeria. Contrary to our expectations of finding minor DNA sequence variations among isolates representing a single M. ulcerans circulating genotype, we found instead two distinct genotypes. One genotype was closely related to isolates from neighbouring regions of Amansie West and Densu, consistent with the predicted local endemic clone, but the second genotype (separated by 138 single nucleotide polymorphisms [SNPs] from other Ghanaian strains) most closely matched M. ulcerans from Nigeria, suggesting another introduction of M. ulcerans to Ghana, perhaps from that country. Both the exotic genotype and the local Ghanaian genotype displayed highly restricted intra-strain genetic variation, with less than 50 SNP differences across a 5.2Mbp core genome within each genotype. Interestingly, there was no discernible spatial clustering of genotypes at the local village scale. Interviews revealed no obvious epidemiological links among BU patients who had been infected with identical M. ulcerans genotypes but lived in geographically separate villages. We conclude that M. ulcerans is spread widely across the region, with multiple genotypes present in any one area. These data give us new perspectives on the behaviour of possible reservoirs and subsequent transmission mechanisms of M. ulcerans. These observations also show for the first time that M. ulcerans can be mobilized, introduced to a new area and then spread within a population. Potential reservoirs of M. ulcerans thus might include humans, or perhaps M. ulcerans-infected animals such as livestock that move regularly between countries.
Differential phase shift quantum key distribution

Quantum key distribution (QKD) has been studied as an ultimate method for secure communications, and it now is emerging as a technology that can be deployed in real fibre networks. Here, we present our QKD experiments based on the differential phase shift QKD (DPS-QKD) protocol. A DPS-QKD system has a simple configuration that is easy to implement with conventional optical communication components, and it is suitable for a high clock rate system. Moreover, although the DPS-QKD system is implemented with an attenuated laser source, it is inherently secure against strong eavesdropping attacks called photon number splitting attacks, which pose a serious threat to conventional QKD systems with attenuated laser sources. We also describe three types of single photon detectors that are suitable for high-speed, long-distance QKD: an up- conversion detector, a superconducting single photon detector, and a sinusoidally gated InGaAs avalanche photodiode. We present our record setting QKD experiments that employed those detectors.
On the construction of data aggregation tree with minimum energy cost in wireless sensor networks: NP-completeness and approximation algorithms

In many applications, it is a basic operation for the sink to periodically collect reports from all sensors. Since the data gathering process usually proceeds for many rounds, it is important to collect these data efficiently, that is, to reduce the energy cost of data transmission. Under such applications, a tree is usually adopted as the routing structure to save the computation costs for maintaining the routing tables of sensors. In this paper, we work on the problem of constructing a data aggregation tree that minimizes the total energy cost of data transmission in a wireless sensor network. In addition, we also address such a problem in the wireless sensor network where relay nodes exist. We show these two problems are NP-complete, and propose O(1)-approximation algorithms for each of them. Simulations show that the proposed algorithms each have good performance in terms of the energy cost.
ANN based SPVC for reactive power compensation of LCC HVDC for offshore wind power transmission

In this paper the concept of reactive power compensation for LCC HVDC system by the use of ANN control based series voltage injection strategy. The series compensating device used here is a transformer less series compensating device called SPVC. The reactive power compensation by this device is a controlled voltage injection strategy. As a controlled voltage injection strategy is used the value of capacitor used is small. Firstly, PI controller is used for SPVC and active and reactive powers for the model are obtained. Then artificial neural network (ANN) control is used to show further improvement in the obtained results. It also explains how there reactive power compensation is significant and the use of this control strategy results in significant reduction in the size and cost of converter terminal.
Comparison between voltage controlled and current controlled buck converter based photovoltaic emulator

Photovoltaic emulator can be designed using different topologies. This paper will outline the simulation of voltage controlled and current controlled buck converter based PV emulator and its performance is evaluated with linear and non-linear load which is compared with the results that would have been obtained if loads were fed from the real PV source. The output characteristics of PV modules and hence, the array greatly depends on the environmental conditions, which makes it very difficult to reproduce and maintain same environmental conditions for testing and comparing the performance of PV power conditioning systems. A photovoltaic emulator facilitates PV systems to be analyzed in a controlled environment where using actual photovoltaic panels would produce inconsistent results for the PV system, due to variability in outside temperature and weather conditions. Extensive simulation results are obtained in MATLAB which show that PV emulator system behaves electrically similar to a real PV source and also the results of voltage and current controlled buck converter PV emulator are compared and finally concluded which topology of PV emulator is a better one.