Miracle-dz/UniFAR-FTUs huggingface dataset:
Materialized view size estimation using sampling

Online Analytical Processing aims at gaining useful information quickly from large amounts of data residing in a Data warehouse. To reduce the time of executing aggregate queries in a data warehousing environment, frequently used aggregates are often pre-computed and materialized in the form of summary views so that future queries can use them directly. Undoubtedly, materializing these summary views can minimize query response time but as the number of views increases exponentially with the number of dimensions, all the views cannot be materialized. However under storage constraint, we must be able to select an optimal number of views to be materialized. To determine the views to be materialized, a Data warehouse administrator may not be able to afford the necessary time to determine the number of rows(size) in each view. Counting actual number of rows present in each view takes considerable time. We explore the use of sampling to estimate the size of views. In this paper we propose a hybrid estimator that takes into account the degree of skew in the data and combines Jacknife estimator with the Schlosser estimator to estimate the size of the view more accurately. The proposed hybrid estimator has been used to estimate the view size in tpc-h benchmark and the results show better estimation results as compared to individual estimators.
A new microrheometric approach reveals individual and cooperative roles for TGF‐β1 and IL‐1β in fibroblast‐mediated stiffening of collagen gels

The stiffness of the extracellular matrix can profoundly influence cell and tissue behaviors. Thus there is an emerging emphasis on understanding how matrix mechanical environments are established, regulated, and modified. Here we develop a microrheo‐metric assay to measure the mechanical properties of a model extracellular matrix (type I collagen gel) and use it to explore cytokine‐induced, cell‐mediated changes in matrix mechanical properties. The microrheometric assay uses micron‐scale ferrimagnetic beads embedded within collagen gels during fibrillogenesis. The beads are magnetized, then subjected to a twisting field, with the aggregate rotation of the beads measured by a magnetometer. The degree of bead rotation reflects the stiffness of the surrounding matrix. We show that the microscale assay provides stiffness measures for collagen gels comparable to those obtained with standard macroscale rheometry. To demonstrate the utility of the assay for biological discovery, we measure stiffness changes in fibroblast‐populated collagen gels exposed to three concentrations of six cytokines over 2 to 14 days. Among the cytokines tested, transforming growth factor‐β1 and interleukin‐1 β enhanced matrix stiffness, and together exerted cooperative effects on cellular modulation of matrix mechanics. The microrheometry approach developed here should accelerate the discovery of biological pathways orchestrating cellular modulation of matrix mechanics. –Leung, L. Y. , Tian, D. , Brangwynne, C. P., Weitz, D. A. , Tschumperlin, D. J. A new microrheometric approach reveals individual and cooperative roles for TGF‐β1 and IL‐1β in fibroblast‐mediated stiffening of collagen gels. FASEB J. 21, 2064–2073 (2007)
For a philosophy of comparisons: the problems of comparative studies in relation with Daoism

ABSTRACT This paper reflects on the problems of cross-cultural interpretations and translations analysing how these are rooted in theories and philosophical assumptions. Inquiring the concept of philosophy per se, the paper discusses key passages of Heidegger and the related problem of 有 (you) and 無 (wu). The conclusion is that to translate such terms, it is necessary to revise the coercive onto-theological assumptions of metaphysics. This can trigger a process of re-grounding grounds with the consequent possibility of language transformation, which, in turn, activates new relations between cultural diversities. Thus, philosophy itself becomes an eminently comparative dialogue between cultures. Without setting a single method for all these problems, the paper argues that comparisons themselves call for necessarily different methodological approaches. Hence, whilst Daoism helps to illuminate these issues defining one of the possibilities that a philosophy of comparisons entails, this same reasoning opens a way for another reading of the Daodejing.
Topology Management in Directional Antenna-Equipped Ad Hoc Networks

With fully directional communications, nodes must track the positions of their neighbors so that communication with these neighbors is feasible when needed. Tracking process introduces an overhead, which increases with the number of discovered neighbors. The overhead can be reduced if nodes maintain only a subset of their neighbors; however, this may increase the length of paths between node pairs in the network. In this work, we study the tradeoffs between node degree and path stretch. We first design a topology control algorithm to optimize this tradeoff. Assuming that nodes communicate with their directional neighbors using circular directional transmissions, we model the original graph as a unit disk graph (UDG). Given a UDG G, our algorithm finds a sparse subgraph G' with a maximum degree of 6, and connecting each node pair u,v by a path of length hopsG (u, v) = O(hopsG(u, v) + log Delta), where Delta is the maximum degree in G, hopsG' (u, v) denotes length of the shortest path between u, v in G. We show that this result is near-optimal. Based on the insights gained from this design, we next construct a simpler, more practical scheme that integrates fully-directional neighbor discovery and maintenance with topology control strategy. We simulate both algorithms and compare their performances.
Jumps and Diffusions in Volatility: It Takes Two to Tango

We consider the following stochastic differential equation for describing financial data evolution: $$ dX_t = b(t, X_t)¸dt + \sigma(t) h(X_t)¸dW_t, \qquad X(0)= x. $$ with a stochastic volatility $\sigma(t)$ (e.g. the combination of a diffusion and a jump process). First we prove the existence and positiveness of the solution of a Cox-Ingersoll-Ross type stochastic differential equation with time varying coefficients, which is a special case of our model. Next, from observation on $X_t$ at times $t_i$ (with non regular sampling scheme), we propose a non-parametric estimator for the volatility (optimal in a certain way). We show its point-wise convergence and its asymptotic normality. After, we propose an estimator for the volatility jump times and prove a Central Limit Theorem. Finally the application of these estimators to the BTP futures (Italian ten year bond futures) and Lira 1 month deposit Eurorates seems to confirm the adequacy of the proposed model.
Using a Wireless Sensor Network to Enhance Video Surveillance

To enhance video surveillance systems, multi-modal sensor integration can be a successful strategy. In this work, a computer vision system able to detect and track people from multiple cameras is integrated with a wireless sensor network mounting PIR (Passive InfraRed) sensors. The two subsystems are briefly described and possible cases in which computer vision algorithms are likely to fail are discussed. Then, simple but reliable outputs from the PIR sensor nodes are exploited to improve the accuracy of the vision system. In particular, two case studies are reported: the first uses the presence detection of PIR sensors to disambiguate between an open door and a moving person, while the second handles motion direction changes during occlusions. Preliminary results are reported and demonstrate the usefulness of the integration of the two subsystems.
Low Cost, High Precision, Autonomous Measurement of Trunk Diameter based on Computer Vision

Trunk diameter is a variable of agricultural interest, used mainly in the prediction of fruit trees production. It is correlated with leaf area and biomass of trees, and consequently gives a good estimate of potential production of the plants. This work presents a low cost, high precision method for autonomous measurement of trunk diameter of fruit trees based on Computer Vision. Autonomous methods based on Computer Vision or other techniques are introduced in the literature for they present important simplifications in the measurement process, requiring little to none human decision making. This presents different advantages for crop management: the method is amenable to be operated by unknowledgeable personnel, with lower operational costs; it results in lower stress levels to knowledgeable personnel, avoiding the deterioration of the measurement quality over time; or it makes the measurement process amenable to be embedded in larger autonomous systems, allowing more measurement to be taken with equivalent costs. In a more personal aspect, the present work is also a successful proof-of-concept for our laboratories and regional research institutions in favor of autonomous measurements based on Computer Vision, opening the door to further investigations in other important agronomic variables measurable by Computer Vision. To date, all existing autonomous methods are either of low precision, or have a prohibitive cost for massive agricultural adoption, leaving the manual Vernier caliper or tape measure as the only choice in most situations. In this work we present an autonomous solution that is costly effective for mass adoption, and its precision is competitive (with slight improvements) over the caliper method.
Formal semantics for expressing optimism: the meaning of HOPE

Optimism is a powerful technique for increasing concurrency. A program can increase concurrency by making an optimistic assumption about its future state, and verifying the assumption in parallel with computations baaed on the optimistic assumption. The use of optimism has been restricted to specialized systems due to the difficulty of writing and understanding optimistic programs. In this paper, we define optimism as any computation that uses rollback. We present a formal semantics for expressing optimism by defining operations for concurrent programs to specify which optimistic computations to roll back, while automating the dependency tracking. We prove that these semantics guarantee some intuitively desirable behaviors. Finally, we describe our programming language implementation based on the semantics.
Long short-term memory networks for noise robust speech recognition

In this paper we introduce a novel hybrid model architecture for speech recognition and investigate its noise robustness on the Aurora 2 database. Our model is composed of a bidirectional Long Short-Term Memory (BLSTM) recurrent neural net exploiting long-range context information for phoneme prediction and a Dynamic Bayesian Network (DBN) for decoding. The DBN is able to learn pronunciation variants as well as typical phoneme confusions of the BLSTM predictor in order to compensate signal disturbances. Unlike conventional Hidden Markov Model (HMM) systems, the proposed architecture is not based on Gaussian mixture modeling. Even without any feature enhancement, our BLSTM-DBN system outperforms a baseline HMM recognizer by up to 18 %. Index Terms: Long Short-Term Memory, Recurrent Neural Networks, Speech Recognition, Noise Robustness, Dynamic Bayesian Networks
A new method for colourizing of multichannel MR images based on real colour of human brain

In this paper, we propose a novel approach for colourizing of multichannel MR images based on real colour of human brain. At first, we use independent component analysis (ICA) to transfer three MR modalities into different representations, which enhance the physical characteristics of tissues. Then, Statistical Features are extracted from three independent components and their wavelet coefficients to generate a feature vector for each pixel of images. Huge amount of features are reduced by using some feature reduction methods such as Principle Component Analysis (PCA) to classify the brain into 3 primary classes. The colour space of Visible Human Project (VHP) dataset is quantized to 10 colours by using a partially supervised algorithm included self-organization map and Linear Vector Quantization (LVQ) algorithms. Acquired 10 colours are allotted to each pixel based on texture and intensity of image in two different steps. Consequently, a fast-automated algorithm is proposed, which has low sensitivity to variation of pixel intensity and precise result regarding to VHP images.
Building boundary tracing and regularization from airborne lidar point clouds

Building boundary is necessary for the real estate industry, flood management, and homeland security applications. The extraction of building boundary is also a crucial and difficult step towards generating city models. This study presents an approach to the tracing and regularization of building boundary from raw lidar point clouds. The process consists of a sequence of four steps: separate building and non-building lidar points; segment lidar points that belong to the same building; trace building boundary points; and regularize the boundary. For separation, a slope based 1D bi-directional filter is used. The segmentation step is a region-growing approach. By modifying a convex hull formation algorithm, the building boundary points are traced and connected to form an approximate boundary. In the final step, all boundary points are included in a hierarchical least squares solution with perpendicularity constraints to determine a regularized rectilinear boundary. Our tests conclude that the uncertainty of regularized building boundary tends to be linearly proportional to the lidar point spacing. It is shown that the regularization precision is at 18 percent to 21 percent of the lidar point spacing, and the maximum offset of the determined building boundary from the original lidar points is about the same as the lidar point spacing. Limitation of lidar data resolution and errors in previous filtering processes may cause artefacts in the final regularized building boundary. This paper presents the mathematical and algorithmic formulations along with stepwise illustrations. Results from Baltimore city, Toronto city, and Purdue University campus are evaluated.
Can the computer replace the adult for storybook reading? A meta-analysis on the effects of multimedia stories as compared to sharing print stories with an adult

The present meta-analysis challenges the notion that young children necessarily need adult scaffolding in order to understand a narrative story and learn words as long as they encounter optimally designed multimedia stories. Including 29 studies and 1272 children, multimedia stories were found more beneficial than encounters with traditional story materials that did not include the help of an adult for story comprehension (g+ = 0.40, k = 18) as well as vocabulary (g+ = 0.30, k = 11). However, no significant differences were found between the learning outcomes of multimedia stories and sharing traditional print-like stories with an adult. It is concluded that multimedia features like animated illustrations, background music and sound effects provide similar scaffolding of story comprehension and word learning as an adult.
Bundle-based pruning in the max-plus curse of dimensionality free method

Recently a new class of techniques termed the max-plus curse of dimensionality-free methods have been developed to solve nonlinear optimal control problems. In these methods the discretization in state space is avoided by using a max-plus basis expansion of the value function. This requires storing only the coefficients of the basis functions used for representation. However, the number of basis functions grows exponentially with respect to the number of time steps of propagation to the time horizon of the control problem. This so called "curse of complexity" can be managed by applying a pruning procedure which selects the subset of basis functions that contribute most to the approximation of the value function. The pruning procedures described thus far in the literature rely on the solution of a sequence of high dimensional optimization problems which can become computationally expensive. In this paper we show that if the max-plus basis functions are linear and the region of interest in state space is convex, the pruning problem can be efficiently solved by the bundle method. This approach combining the bundle method and semidefinite formulations is applied to the quantum gate synthesis problem, in which the state space is the special unitary group (which is non-convex). This is based on the observation that the convexification of the unitary group leads to an exact relaxation. The results are studied and validated via examples.
Being touched – the transformative potential of nurturing touch practices in relation to toddlers’ learning and emotional well-being

ABSTRACT The article investigates how nurturing touch practices, such as gentle brush massage, finger massage and body massage, are applied in 10 Danish toddlers’ early childhood education and care (ECEC) settings. Thirteen practitioners contributed to the study with written narratives on their experiences with nurturing touch practices and how they influenced their relationship with the children and the conditions for toddlers’ emotional well-being and learning at the nursery or family day care. This qualitative case study is built on a relational ontology and draws on Hundeide’s ([2007]. When empathic care is obstructed – excluding the child from the zone of intimacy. In S. Bråten (Ed.), On being moved from mirror neurons to empathy. Amsterdam: John Benjamins) concept of a zone of intimacy. The practitioners describe how nurturing touch practices can enhance their sensitivity and the intersubjective space between them and the children. The practitioners also describe how toddlers seem to become more attentive to their bodies, more relaxed and flexible. The study invites policy-makers and practitioners to broaden their focus on children’s learning and to consider how the mutual relatedness between practitioner and child influence children’s bodily, non-verbal and emotional experiences and participation.
Efficient option pricing under Lévy processes, with CVA and FVA

We generalize the Piterbarg [1] model to include (1) bilateral default risk as in Burgard and Kjaer [2], and (2) jumps in the dynamics of the underlying asset using general classes of Lévy processes of exponential type. We develop an efficient explicit-implicit scheme for European options and barrier options taking CVA-FVA into account. We highlight the importance of this work in the context of trading, pricing and management a derivative portfolio given the trajectory of regulations.
Spatial Joins: Algorithms, Cost Models and Optimization

This chapter describes algorithms, cost models and optimization techniques for spatial joins. Joins are among the most common queries in Spatial Database Management Systems. Due to their importance and high processing cost, a number of algorithms have been proposed covering all possible cases of indexed and non-indexed inputs. We first describe some popular methods for processing binary spatial joins and provide models for selectivity and cost estimation. Then, we discuss evaluation of multiway This chapter appears in the book Spatial Databases: Technologies, Techniques and Trends by Yannis Manalopoulos, Apostolos Papadopoulos and Michael Gr. Vassilakopoulos. Copyright © 2005, Idea Group Inc. Copying or distributing in print or electronic forms without written permission of Idea Group Inc. is prohibited. 701 E. Chocolate Avenue, Suite 200, Hershey PA 17033-1240, USA Tel: 717/533-8845; Fax 717/533-8661; URL-http://www.idea-group.com IDEA GROUP PUBLISHING 156 Mamoulis, Theodoridis & Papadias Copyright © 2005, Idea Group Inc. Copying or distributing in print or electronic forms without written permission of Idea Group Inc. is prohibited. spatial joins by integrating binary algorithms and synchronous tree traversal. Going one step further, we show how analytical models can be used to combine the various join operators in optimal evaluation plans. The chapter can serve as a comprehensive reference text to the researcher who wants to learn about this important spatial query operator and to the developer who wants to include spatial query processing modules in a Database System.
Journal of Economic Behavior & Organization Rating Agencies' Signals during the European Sovereign Debt Crisis: Market Impact and Spillovers

JEL classification: F31 G15 G24 Keywords: European sovereign debt crisis Agencies' signals Spillover effect Credit outlook/watch Foreign exchange market a b s t r a c t The ongoing financial crisis has drawn considerable attention to the role of credit rating agencies in the financial system. We examine how the foreign exchange market reacts to sovereign credit events prior to (2000–2006) and during the crisis (2006–2010). The sample includes a broad set of countries in Europe and Central Asia in order to investigate spillover effects. We find that rating agencies' signals do affect the own-country exchange rate and we identify strong spillover effects to other countries' exchange rates in the region. In both cases, the impact of outlook and watch signals is stronger than the impact of actual rating changes. Market reactions and spillovers are far stronger during the financial crisis period than pre-crisis. Negative news from all three major agencies has an impact, whereas only Moody's positive news produces a reaction. Negative news from Fitch tends to have the strongest effect. The findings are important in enhancing understanding of the role of rating agencies and the market response to their signals.
Measuring the interaction complexity of teleoperated systems

Concerns control of telescience systems in space by ground-based scientists, as in the Canadian Advanced Protein Crystallization Apparatus (CAPCA). We describe in this report how the formal modelling and analysis of the operator-system interaction makes it possible to evaluate the "error-proneness" of the operator interface in terms of the definition and measurement of metrics related to the complexity of the operator decisions since reduced complexity often means improved reliability. The intent is to be able to compare alternative interfaces to the very same telescience infrastructure in terms of cognitive complexity (and therefore error-proneness) by carefully evaluating the operator decision-making interactions with the system in meaningful ways. As a result, our report concludes by defining candidate complexity metrics and by discussing how they might be validated by experimental work.
A new method for the analytical determination of the complex relative permeance function in linear electric machines with slotted air gap

The complex relative permeance function is a useful mathematical tool to study the magnetic field of electric machines with slotted air gap. In the literature, the complex permeance function is usually identified by means of numerical techniques based on conformal mapping. In this paper an alternative analytical approach is proposed. The method is based on solving the magnetostatic differential field equation over a portion of the slotted air gap by imposing suitable boundary conditions in the slot opening region. Such boundary conditions exploit the mathematical law which governs the divergence of the magnetic field in the neighborhood of corner-shaped ferromagnetic regions. Furthermore, the results of Carter theory on slot fringing effects on the air gap field are used. A simple easy-to-compute formula is obtained for the complex permeance function. Its accuracy is assessed by comparison with Finite Element Analysis (FEA).