Miracle-dz/UniFAR-FTUs huggingface dataset:
Sparsity-Promoting Bayesian Dynamic Linear Models

Sparsity-promoting priors have become increasingly popular over recent years due to an increased number of regression and classification applications involving a large number of predictors. In time series applications where observations are collected over time, it is often unrealistic to assume that the underlying sparsity pattern is fixed. We propose here an original class of flexible Bayesian linear models for dynamic sparsity modelling. The proposed class of models expands upon the existing Bayesian literature on sparse regression using generalized multivariate hyperbolic distributions. The properties of the models are explored through both analytic results and simulation studies. We demonstrate the model on a financial application where it is shown that it accurately represents the patterns seen in the analysis of stock and derivative data, and is able to detect major events by filtering an artificial portfolio of assets.
Pathogen fitness components and genotypes differ in their sensitivity to nutrient and temperature variation in a wild plant–pathogen association

Understanding processes maintaining variation in pathogen life‐history stages affecting infectivity and reproduction is a key challenge in evolutionary ecology. Models of host–parasite coevolution are based on the assumption that genetic variation for host–parasite interactions is a significant cause of variation in infection, and that variation in environmental conditions does not overwhelm the genetic basis. However, surprisingly little is known about the stability of genotype–genotype interactions under variable environmental conditions. Here, using a naturally occurring plant–pathogen interaction, I tested whether the two distinct aspects of the infection process – infectivity and transmission potential – vary over realistic nutrient and temperature gradients. I show that the initial pathogen infectivity and host resistance responses are robust over the environmental gradients. However, for compatible responses there were striking differences in how different pathogen life‐history stages and host and pathogen genotypes responded to environmental variation. For some pathogen genotypes even slight changes in temperature arrested spore production, rendering the developing infection ineffectual. The response of pathogen genotypes to environmental gradients varied in magnitude and even direction, so that their rankings changed across the abiotic gradients. Hence, the variable environment of spatially structured host–parasite interactions may strongly influence the maintenance of polymorphism in pathogen life‐history stages governing transmission, whereas evolutionary trajectories of infectivity may be unaffected by the surrounding environment.
Corpus-based Conceptual Characterisation of Verbal Predicate Structures

This paper describes performed research into the feasibility of creating computer-aided methods for knowledge extraction from an English corpus with the aid of existing lexical resources and analysis tools. Starting with subcategorised surface syntactic structures which give valuable information about the semantic and cognitive aspects of a (sub)language, the analysis is transferred to the abstract representation level of deep cases or thematic roles. These reveal information about the conceptual relations between the verbal arguments and the predicate that exist in the semantic domain under consideration. A semantic characterisation of the theta roles themselves will be supplied by using the lexical information of WordNet ([9])
Grade of service balancing for originating and handoff calls and system cost minimization using genetic algorithm

With the increasing popularity of mobile wireless communication systems, customers are expecting the same quality of service (QoS), availability and performance from the wireless communication networks as the traditional wire-line networks. Currently the research work on radio channel allocation in cellular mobile systems focuses mainly on two aspects, improving the user admission capability and protecting the connection continuity for handoff calls as a QoS constraint. However, given a QoS constraint, a wireless network has to sacrifice its capacity in order to support an increase in handoff rate. In this paper, we propose and analyze a different handoff scheme which not only gives priority to handoff calls, due to importance of them from QoS standpoint, but also protects originating calls to keep system capacity at an acceptable level. We will describe the optimum design of our scheme to minimize the system cost. We use genetic algorithm (GA) to solve optimum design problem. To do so, a model of cost characteristics has been derived for the proposed scheme. Indeed, the robustness of our approach is that analytically minimizes the system cost. We use a system model defined by a two dimensional Markov chain which computes mathematically the performance in terms of the blocking probability of originating calls, forced termination probability and call incompletion probability. Results are compared with conventional guard channel (GC) scheme
A Photometric Sampling Strategy for Reflectance Characterization and Transference

Rendering 3D models with real world reflectance properties is an open research problem with significant applications in the field of computer graphics and image understanding. In this paper, our interest lies on the characterization and transference of appearance from a source object onto a target 3D shape. To this end, a three-step strategy is proposed. In the first step, reflectance is sampled by rotating a light source in concentric circles around the source object. Singular value decomposition is then used for describing, in a pixel-wise manner, appearance features such as color, texture and specular regions. The second step introduces a Markov random field transference method based on surface normal correspondence between the source object and a synthetic sphere. The aim of this step is to generate a sphere whose appearance emulates that of the source material. In the third step, final transference of properties is performed from the surface normals of the generated sphere to the surface normals of the target 3D model. Experimental evaluation validates the suitability of the proposed strategy for transferring appearance from a variety of materials between diverse shapes.
Pulsation-Initiated Mass Loss in Luminous Blue Variables: A Parameter Study

Abstract Luminous blue variables (LBVs) are characterized by semi-periodic episodes of enhanced mass-loss, or outburst. The cause of these outbursts has thus far been a mystery. One explanation is that they are initiated by κ-effect pulsations in the atmosphere caused by a blocking of luminosity at temperatures near the so-called “iron bump” (T ~ 200,000 K), where the Fe opacity suddenly increases and blocks the luminosity. Due to a lag in the onset of convection, the luminosity can build until it exceeds the Eddington limit locally, seeding pulsations and possibly driving some mass from the star. We present preliminary results from a parameter study focusing on the conditions necessary to trigger normal S-Dor type (as opposed to extreme η-Car type) outbursts. We find that as Y increases or Z decreases, the pulsational amplitude decreases and outburst-like behavior, indicated by a large, sudden increase in photospheric velocity, becomes less likely.
A constructive proof of the Lovász local lemma

The Lovasz Local Lemma [2] is a powerful tool to prove the existence of combinatorial objects meeting a prescribed collection of criteria. The technique can directly be applied to the satisfiability problem, yielding that a k-CNF formula in which each clause has common variables with at most 2(k-2) other clauses is always satisfiable. All hitherto known proofs of the Local Lemma are non-constructive and do thus not provide a recipe as to how a satisfying assignment to such a formula can be efficiently found. In his breakthrough paper [3], Beck demonstrated that if the neighbourhood of each clause be restricted to O(2(k/48)), a polynomial time algorithm for the search problem exists. Alon simplified and randomized his procedure and improved the bound to O(2(k/8)) [4]. Srinivasan presented in [9] a variant that achieves a bound of essentially O(2(k/4)). In [11], we improved this to O(2(k/2)). In the present paper, we give a randomized algorithm that finds a satisfying assignment to every k-CNF formula in which each clause has a neighbourhood of at most the asymptotic optimum of 2(k-5)-1 other clauses and that runs in expected time polynomial in the size of the formula, irrespective of k. If k is considered a constant, we can also give a deterministic variant. In contrast to all previous approaches, our analysis does not anymore invoke the standard non-constructive versions of the Local Lemma and can therefore be considered an alternative, constructive proof of it.
Realizing an Integrated Electronic Commerce Portal System

This experience report 1 describes the design and implementation of an electronic commerce portal system for insurance companies which supports the insurance agents in their daily work. The electronic commerce portal, called IPSI, is used within an intranet. The insurance agents need information about their industrial and private customers and have to be supported in organizing their work by an organizer with reminder function, address management, etc. The insurance company has the goal to provide its employees with the most current information about its product portfolio and tariffs as well as wordings of the law and comments on it. An electronic commerce portal therefore has to provide a multitude of functions. The advantage of a portal lies in the integration of different software systems that provide these functions and thus leads the users directly to the desired information. They do not have to search awkwardly and are not served with irrelevant information. An object oriented design using UML, the realization of adequate adaptors for the integration of different heterogeneous software systems using the Java programming language, and the use of the middleware CORBA for communication within the portal were objectives of the project. This project was realized by the University of Dortmund in cooperation with different insurance and software companies. The electronic commerce portal was implemented as a prototype for a certain insurance company, including the integration of one of their legacy systems.
Chemical Enrichment in Damped Lyα Systems from Hierarchical Galaxy Formation Models

We investigate chemical enrichment in damped Lyα (DLA) systems in the hierarchical structure formation scenario using a semianalytic model of galaxy formation. The model developed by Nagashima, Totani, Gouda & Yoshii takes into account various selection effects on high-redshift galaxies and can reproduce fundamental observational properties of galaxies, such as luminosity functions and number-magnitude/redshift relations. DLA systems offer the possibility of measuring metal abundance more accurately than faint galaxies. For example, recent measurements of the zinc abundance can help in understanding processes of metal pollution and star formation in DLA systems because zinc is virtually unaffected by dust depletion. Here we focus on this advantage for observations exploring the metallicity evolution in DLA systems at high redshifts. We can consistently show the metallicity evolution for reasonable models. The models also reproduce fundamental properties of the local galaxy population. This result suggests that the chemical evolution of DLA systems can be consistently reconciled with the observational features of typical galaxies. We also investigate other properties of DLA systems (column density distribution and mass density of cold gas) and find that star formation in massive galaxies should be more active than that in low-mass galaxies, which is consistent with the results of Nagashima et al. and Cole et al. in which the star formation timescale is set by the cold gas mass fraction in local spiral galaxies. Finally, we discuss host galaxies associated with DLA systems. We conclude from the observations that they primarily consist of sub-L* and/or dwarf galaxies.
Adaptive algorithms for problems involving black-box Lipschitz functions

Suppose we are given a black-box evaluator (an oracle that returns the function value at a given point) for a Lipschitz function with a known Lipschitz constant. We consider queries that can be answered about the function by using a finite number of black-box evaluations. Specifically, we study the problems of approximating a Lipschitz function, approximately integrating a Lipschitz function, approximately minimizing a Lipschitz function, and computing the winding number of a Lipschitz curve in R around a point. The goal is to minimize the number of evaluations used for answering a query. Because the complexity of the problem instances varies widely, depending on the actual function, we wish to design adaptive algorithms whose performance is close to the best possible on every problem instance. We give optimally adaptive algorithms for winding number computation and univariate approximation and integration. We also give a near-optimal adaptive algorithm for univariate approximation when the output of function evaluations is corrupted by random noise. For optimization over higher dimensional domains, we prove that good adaptive algorithms are impossible. Thesis Supervisor: Erik D. Demaine Title: Assistant Professor
Improvements in rate of development and magnitude of force with intense auditory stimuli in patients with Parkinson’s disease

Patients with Parkinson’s disease can show brief but dramatic normalization of motor activity in highly arousing situations, a phenomenon often termed paradoxical kinesis. We sought to mimic this in a controlled experimental environment. Nine patients with Parkinson’s disease and nine age‐matched healthy controls were asked to grip a force dynamometer as quickly and strongly as possible in response to a visual cue. A loud (96 dB) auditory stimulus was delivered at the same time as the visual cue in ∼50% of randomly selected trials. In patients with Parkinson’s disease, the experiment was conducted after overnight withdrawal of antiparkinsonian drugs and again 1 h after patients had taken their usual morning medication. Patients showed improvements in the peak rate of force development and the magnitude of force developed when loud auditory stimuli accompanied visual cues. Equally, they showed improvements in the times taken to reach the peak rate of force development and their maximal force. The paradoxical facilitatory effect of sound was similar whether patients were off or on their usual antiparkinsonian medication, and could be reproduced in age‐matched healthy controls. We conclude that motor improvement induced by loud auditory stimuli in Parkinson’s disease is related to a physiological phenomenon which survives both with and after withdrawal of antiparkinsonian medication. The potential independence of the mediating pathways from the dopaminergic system provides impetus for further investigation as it may yield a novel nondopaminergic target for therapeutic manipulation in Parkinson’s disease.
Two Stages Refinement of Query Translation for Pivot Language Approach to Cross Lingual Information Retrieval: A Trial at CLEF 2003

This paper reports experimental results of cross-lingual information retrieval from German to Italian. The authors are concerned with CLIR in the case that available language resources are very limited. Thus transitive translation of queries using English as a pivot language was used to search Italian document collections for German queries without any direct bilingual dictionary or MT system of these two languages. In order to remove irrelevant translations produced by the transitive translation, we propose a disambiguation technique, in which two stages of refinement of query translation are executed. Basically, this refinement is based on the idea of pseudo relevance feedback. In the first stage, for each source query term, we select a translation candidate that appears most frequently in the set of top-ranked documents searched for a set of terms provided via transitive translation of the source query. Next, in the second stage, a standard query expansion based on pseudo relevance feedback is conducted. Our experiment result showed that the two stages refinement method is able to improve significantly search performance of bilingual IR using a pivot language. However, it also turned out that performance of this method is inferior to that of machine translation method.
Developmental Robotics: Theory and Experiments

A hand-designed internal representation of the world cannot deal with unknown or uncontrolled environments. Motivated by human cognitive and behavioral development, this paper presents a theory, an architecture, and some experimental results for developmental robotics. By a developmental robot, we mean that the robot generates its “brain” (or “central nervous system,” including the information processor and controller) through online, real-time interactions with its environment (including humans). A new Self-Aware Self-Effecting (SASE) agent concept is proposed, based on our SAIL and Dav developmental robots. The manual and autonomous development paradigms are formulated along with a theory of representation suited for autonomous development. Unlike traditional robot learning, the tasks that a developmental robot ends up learning are unknown during the programming time so that the task-specific representation must be generated and updated through real-time “living” experiences. Experimental results with SAIL and Dav developmental robots are presented, including visual attention selection, autonomous navigation, developmental speech learning, range-based obstacle avoidance, and scaffolding through transfer and chaining.
FavourQueue: a Stateless Active Queue Management to Speed Up Short TCP Flows (and others too!)

This paper presents and analyses the implementation of a novel active queue management (AQM) named FavorQueue that aims to improve delay transfer of short lived TCP flows over best-effort networks. The idea is to dequeue packets that do not belong to a flow previously enqueued first. The rationale is to mitigate the delay induced by long-lived TCP flows over the pace of short TCP data requests and to prevent dropped packets at the beginning of a connection and during recovery period. Although the main target of this AQM is to accelerate short TCP traffic, we show that FavorQueue does not only improve the performance of short TCP traffic but also improves the performance of all TCP traffic in terms of drop ratio and latency whatever the flow size. In particular, we demonstrate that FavorQueue reduces the loss of a retransmitted packet, decreases the number of dropped packets recovered by RTO and improves the latency up to 30% compared to DropTail. Finally, we show that this scheme remains compliant with recent TCP updates such as the increase of the initial slow-start value.
A Low-Cost Ultra Low Profile Phased Array System for Mobile Satellite Reception Using Zero-Knowledge Beamforming Algorithm

In this paper, a stair-planar phased array antenna system for mobile broadcast satellite reception in Ku-band will be introduced. The height of the antenna is only 6 cm and the system has two-dimensional electronic scanning capability. The design procedures of low profile high gain microstrip sub-array antennas, low noise amplifiers, hybrid analog phase shifters, along with a novel fast electronic beamforming algorithm will be discussed in this paper. The mobile phased array antenna receives LHCP and RHCP signals simultaneously. For each polarization 496 microstrip elements have been used to provide a radiation gain of 31.5 dBi. This phased array system scans plusmn2.8deg in azimuth and plusmn20deg in elevation with less than 3 dB scanning loss. The main objective of this design is to develop a Ku-band phased array system with very low cost components and a minimum number of tracking sensors. A novel beamforming algorithm compensates for the fabrication inaccuracies of the microwave components and variations in their characteristics due to ambient changes. Neither a priori knowledge of the satellite's direction, nor the phase-voltage characteristic of the phase shifters are required in this algorithm which results in eliminating an expensive laborious calibration procedure. The real time field tests verify that the developed mobile antenna system can nullify the base vehicle yaw disturbances up to 60 deg/s and 85 deg/s 2.
Convergence Rates of Distributed Nesterov-Like Gradient Methods on Random Networks

We consider distributed optimization in random networks where N nodes cooperatively minimize the sum Σi=1N fi(x) of their individual convex costs. Existing literature proposes distributed gradient-like methods that are computationally cheap and resilient to link failures, but have slow convergence rates. In this paper, we propose accelerated distributed gradient methods that 1) are resilient to link failures; 2) computationally cheap; and 3) improve convergence rates over other gradient methods. We model the network by a sequence of independent, identically distributed random matrices {W(k)} drawn from the set of symmetric, stochastic matrices with positive diagonals. The network is connected on average and the cost functions are convex, differentiable, with Lipschitz continuous and bounded gradients. We design two distributed Nesterov-like gradient methods that modify the D-NG and D-NC methods that we proposed for static networks. We prove their convergence rates in terms of the expected optimality gap at the cost function. Let k and K be the number of per-node gradient evaluations and per-node communications, respectively. Then the modified D-NG achieves rates O(logk/k) and O(logK/ K), and the modified D-NC rates O(1/k2) and O(1/ K2-ξ), where ξ > 0 is arbitrarily small. For comparison, the standard distributed gradient method cannot do better than Ω(1/k2/3) and Ω(1/ K2/3), on the same class of cost functions (even for static networks). Simulation examples illustrate our analytical findings.
DISCOVERY OF X-RAY EMISSION FROM THE WOLF–RAYET STAR WR 142 OF OXYGEN SUBTYPE

We report the discovery of weak yet hard X-ray emission from the Wolf–Rayet (WR) star WR 142 with the XMM-Newton X-ray telescope. Being of spectral subtype WO2, WR 142 is a massive star in a very advanced evolutionary stage shortly before its explosion as a supernova or γ-ray burst. This is the first detection of X-ray emission from a WO-type star. We rule out any serendipitous X-ray sources within ≈1″ of WR 142. WR 142 has an X-ray luminosity of LX ≈ 7 × 1030 erg s−1, which constitutes only ≲10−8 of its bolometric luminosity. The hard X-ray spectrum suggests a plasma temperature of about 100 MK. Commonly, X-ray emission from stellar winds is attributed to embedded shocks due to the intrinsic instability of the radiation driving. From qualitative considerations we conclude that this mechanism cannot account for the hardness of the observed radiation. There are no hints for a binary companion. Therefore the only remaining, albeit speculative explanation must refer to magnetic activity. Possibly related, WR 142 seems to rotate extremely fast, as indicated by the unusually round profiles of its optical emission lines. Our detection implies that the wind of WR 142 must be relatively transparent to X-rays, which can be due to strong wind ionization, wind clumping, or nonspherical geometry from rapid rotation.