Miracle-dz/UniFAR-FTUs huggingface dataset:
Convex optimization techniques for fitting sparse Gaussian graphical models

We consider the problem of fitting a large-scale covariance matrix to multivariate Gaussian data in such a way that the inverse is sparse, thus providing model selection. Beginning with a dense empirical covariance matrix, we solve a maximum likelihood problem with an l1-norm penalty term added to encourage sparsity in the inverse. For models with tens of nodes, the resulting problem can be solved using standard interior-point algorithms for convex optimization, but these methods scale poorly with problem size. We present two new algorithms aimed at solving problems with a thousand nodes. The first, based on Nesterov's first-order algorithm, yields a rigorous complexity estimate for the problem, with a much better dependence on problem size than interior-point methods. Our second algorithm uses block coordinate descent, updating row/columns of the covariance matrix sequentially. Experiments with genomic data show that our method is able to uncover biologically interpretable connections among genes.
Inductor based Circuit Techniques for Chip-to-Chip Interconnect and Standing Wave Clock Generation

There is few report of applying on-chip inductor to high-speed digital circuit, while it is useful passive element for RF circuit design. The on-chip inductor helps the digital circuit operate faster and can reduce the power consumption, because the inductance can cancel the capacitive load of the active device. In this manuscript, we present two conspicuous cases where on-chip inductor has been applied effectively in digital circuit design. One is spiral-inductor based wireless chip-interconnect. As an alternative of single chip system LSI, 3D-IC fabrication attracts attention and wireless chip-to-chip interconnects using capacitive and inductive coupling are now under development [1],[2]. They are expected to overcome the process cost and low yield problems of the silicon through-via technologies [3]. Another is over 10GHz clock generation and distribution using standing-wave network with inductively loaded. Global clock distribution becomes increasingly difficult for multi-GHz microprocessors, because skew and jitter are proportional to latency, which does not scale with clock period for the conventional tree network. Resonant techniques are expected to overcome the clock distribution problems [4]-[6].
The economics of German unification : an introduction

Following German reunification in 1990, East Germany's centrally planned economy was abolished and replaced by West Germany's social market economy. Western Germany has since provided vast financial support to aid the transformation, and enable eastern Germany to catch-up with western Germany's productivity and living standards. This book evaluates the main events and their outcomes since mid 1990 and the associated policy issues. The authors assess the medium- to long-term growth prospects of eastern Germany and the wider implications for western Germany and Europe.
Multiarea Stochastic Unit Commitment for High Wind Penetration in a Transmission Constrained Network

In this paper we present a unit commitment model for studying the impact of large-scale wind integration in power systems with transmission constraints and system component failures. The model is formulated as a two-stage stochastic program with uncertain wind production in various locations of the network as well as generator and transmission line failures. We present a scenario selection algorithm for selecting and weighing wind power production scenarios and composite element failures, and we provide a parallel dual decomposition algorithm for solving the resulting mixed-integer program. We validate the proposed scenario selection algorithm by demonstrating that it outperforms alternative reserve commitment approaches in a 225 bus model of California with 130 generators and 375 transmission lines. We use our model to quantify day-ahead generator capacity commitment, operating cost impacts, and renewable energy utilization levels for various degrees of wind power integration. We then demonstrate that failing to account for transmission constraints and contingencies can result in significant errors in assessing the economic impacts of renewable energy integration. Subject classifications: unit commitment; stochastic programming; wind power; transmission constraints. Area of review: Environment, Energy, and Sustainability.
Adaptive Antenna Selection Algorithm for Spatial Multiplexing MIMO Systems

This paper proposes a new adaptive algorithm for antenna selection in Spatial Multiplexing MIMO systems over a fading channel. This algorithm addresses the signal processing computation complexity, which represents the main concern in antenna selection technique's implementation. Indeed, when compared to the optimum antenna selection algorithm, the proposed one showed a significant reduction of the signal processing computation for a limited degradation of the bit-error-rate.
Diffusion Equations over Arbitrary Triangulated Surfaces for Filtering and Texture Applications

In computer graphics, triangular mesh representations of surfaces have become very popular. Compared with parametric and implicit forms of surfaces, triangular mesh surfaces have many advantages such as being easy to render, being convenient to store, and having the ability to model geometric objects with arbitrary topology. In this paper, we are interested in data processing over triangular mesh surfaces through partial differential equations (PDEs). We study several diffusion equations over triangular mesh surfaces and present corresponding numerical schemes to solve them. Our methods work for triangular mesh surfaces with arbitrary geometry (the angles of each triangle are arbitrary) and topology (open meshes or closed meshes of arbitrary genus). Besides the flexibility, our methods are efficient due to the implicit/semi-implicit time discretization. We finally apply our methods to several filtering and texture applications such as image processing, texture generation, and regularization of harmonic maps over triangular mesh surfaces. The results demonstrate the flexibility and effectiveness of our methods.
Quadratic image of a ball: Towards efficient description of the boundary

We propose a simple efficient machinery for computing “nearly exact” boundary of the image of euclidean ball under multidimensional quadratic mapping. It is based on necessary conditions for a point to be mapped to the boundary. Several special cases are considered, the results of numerical simulations are presented, in particular, as applied to multiobjective optimization and Pareto set discovery.
Removing useless APs and fingerprints from WiFi indoor positioning radio maps

Maintaining consistent radio maps for WiFi fingerprinting-based indoor positioning systems is an essential step to improve the performance of the positioning engines. The radio maps consist of WiFi fingerprints collected at a predefined set of positions/places within a positioning area. Each fingerprint consists of the identification and radio signal level of the surrounding Access Points (APs). Due to the wide proliferation of WiFi networks, it is very common to observe 10 to 20 APs at a single position and more than 50 APs across a single building. However, in practical, not all of the detected APs are useful for the position estimation process. Some of them might have weak signals at certain positions or might have less significance for a position's fingerprint. Thus, those useless APs will add additional computational overheads during the position estimation, and consequently they will reduce the overall performance of the positioning engines. A similar phenomenon also occurs with some of the collected fingerprints. While it is widely accepted that the larger and more detailed the radio map is, the better is the accuracy of the positioning system, we found that some of the fingerprint samples on the radio maps do not contribute significantly to the estimation process. In this paper, we propose two methods for filtering the positioning radio maps: APs filtering and Fingerprints filtering. Then we report on the results of a set of experiments that have been done to evaluate the performance of a WiFipositioning radio map before and after applying the filtering approaches. The results show that there is possibility to simplify the radio maps of the positioning engines without significant degradation on the positioning precision and accuracy, and therefore to reduce the processing time for estimating the position of a tracked WiFi tag. This result has an important impact on increasing the number of tags a single instance of a WiFi positioning engine can handle at a time.
Hybrid Analog-Digital Beamforming: How Many RF Chains and Phase Shifters Do We Need?

This paper considers hybrid beamforming (HB) for downlink multiuser massive MIMO systems with frequency selective channels. For this system, first we quantify the required number of radio frequency (RF) chains and phase shifters (PSs) such that the proposed HB achieves the same performance as that of the digital beamforming (DB) which utilizes N (number of transmitter antennas) RF chains. We show that the performance of the DB can be achieved with our HB just by utilizing rt RF chains and 2rt(N − rt + 1) PSs, where rt ≤ N is the rank of the combined digital precoder matrices of all sub-carriers. Second, we provide a simple and novel approach to reduce the number of PSs with only a negligible performance degradation. Numerical results reveal that only 20− 40 PSs per RF chain are sufficient for practically relevant parameter settings. Finally, for the scenario where the deployed number of RF chains (Na) is less than rt, we propose a simple user scheduling algorithm to select the best set of users in each sub-carrier. Simulation results validate theoretical expressions, and demonstrate the superiority of the proposed HB design over the existing HB designs in both flat fading and frequency selective channels.
Clearance of influenza virus respiratory infection in mice lacking class I major histocompatibility complex-restricted CD8+ T cells

Transgenic mice homozygous for a beta 2-microglobulin (beta 2-m) gene disruption and normal mice that had been treated with a CD8-specific mAb were infected intranasally with an H3N2 influenza A virus. Both groups of CD8T cell-deficient mice eliminated the virus from the infected respiratory tract. Potent CTL activity was detected in lung lavage populations taken from mice with intact CD8+ T cell function, with minimal levels of cytotoxicity being found for inflammatory cells obtained from the antibody-treated and beta 2-m mutant mice. We therefore conclude that cells infected with an influenza A virus can be cleared from the respiratory tract of mice lacking both functional class I major histocompatibility complex (MHC) glycoproteins and class I MHC-restricted, CD8+ effector T cells.
Giant epidermal cyst of the gluteal region

Epidermal cysts are common, benign, intradermal or subcutaneous, typically asymptomatic masses, ranging from 1 to 4 cm in size. They may occur anywhere in the body, with a predilection for the face, neck, and trunk. Transformation to squamous-cell carcinoma is rare. We present a case of a 61-year-old male patient with a large, growing mass in his posterior left gluteal region. Given the concern for a malignancy, he was referred to a surgical oncologist. Magnetic resonance imaging (MRI) without contrast was performed due to poor renal function and revealed a large cystic mass in the left gluteal subcutaneous soft tissues that was subsequently excised. Pathological examination revealed an epidermal inclusion cyst that measured 17.8 × 13.18 × 5.8 cm. To our knowledge, this is the largest epidermal inclusion cyst reported in the English literature.
An Elliptic superpotential for softly broken N=4 supersymmetric Yang-Mills theory

An exact superpotential is derived for the = 1 theories which arise as massive deformations of = 4 supersymmetric Yang-Mills (SYM) theory. The superpotential of the SU(N) theory formulated on 3 × S1 is shown to coincide with the complexified potential of the N-body elliptic Calogero-Moser hamiltonian. This superpotential reproduces the vacuum structure predicted by Donagi and Witten for the corresponding four-dimensional theory and also transforms covariantly under the S-duality group of = 4 SYM. The analysis yields exact formulae with interesting modular properties for the condensates of gauge-invariant chiral operators in the four-dimensional theory.
A REGRESSION MODEL FOR MULTILEVEL HOMOGENEITY ANALYSIS

One of the basic techniques that analyzes categorical data is homogeneity analysis. The technique originated in the work of Guttman [17] as a method of scale construction using reciprocal averaging. Burt [5] described homogeneity analysis as a principal components analysis of qualitative data. Hayashi [19] stressed homogeneity analysis as one possible way of quantifying categories. It should be noted that earlier work by Hirschfeld [21] and Fisher [13] concentrated on the bivariate case (analysis of contingency tables). Extensive reviews on the history of homogeneity analysis can be found in de Leeuw [8], Nishisato [26], Benz ecri [3], Tenenhaus and Young [28] and Gifi [14].
A top- 10 approach to prefetching on the web

In the World Wide Web bottlenecks close to popular servers are very common. These bottlenecks can be attributed to the servers' lack of computing power and the network traac induced by the increased number of access requests. One way to eliminate these bottlenecks is through the use of caching. However, several recent studies suggest that the maximum hit rate achievable by any caching algorithm is just 40% to 50%. Prefetching techniques may be employed to further increase the cache hit rate, by anticipating and prefetching future client requests. This paper proposes a Top-10 approach to prefetching, which combines the servers' active knowledge of their most popular documents (their Top-10) with client access prooles. Based on these prooles, clients request and servers forward to them, regularly, their most popular documents. The scalability of the approach lays in that a web server's clients may be proxy servers, which in turn forward their Top-10 to their frequent clients which may be proxies as well, resulting in a dynamic hierarchical scheme, responsive to users access patterns as they evolve over time. We use trace driven simulation based on access logs from various servers to evaluate Top-10 prefetching. Performance results suggest that the proposed policy can anticipate more than 40% of a client's requests while increasing network traac by no more than 10% in most cases.
DP-space: Bayesian Nonparametric Subspace Clustering with Small-variance Asymptotics

Subspace clustering separates data points approximately lying on union of affine subspaces into several clusters. This paper presents a novel nonparametric Bayesian subspace clustering model that infers both the number of subspaces and the dimension of each subspace from the observed data. Though the posterior inference is hard, our model leads to a very efficient deterministic algorithm, DP-space, which retains the nonparametric ability under a smallvariance asymptotic analysis. DP-space monotonically minimizes an intuitive objective with an explicit tradeoff between data fitness and model complexity. Experimental results demonstrate that DP-space outperforms various competitors in terms of clustering accuracy and at the same time it is highly efficient.
Regulation of the metC-cysK Operon, Involved in Sulfur Metabolism in Lactococcus lactis

ABSTRACT Sulfur metabolism in gram-positive bacteria is poorly characterized. Information on the molecular mechanisms of regulation of genes involved in sulfur metabolism is limited, and no regulator genes have been identified. Here we describe the regulation of the lactococcal metC-cysK operon, encoding a cystathionine β-lyase (metC) and cysteine synthase (cysK). Its expression was shown to be negatively affected by high concentrations of cysteine, methionine, and glutathione in the culture medium, while sulfur limitation resulted in a high level of expression. Other sulfur sources tested showed no significant effect on metC-cysK gene expression. In addition we found that O-acetyl-l-serine, the substrate of cysteine synthase, was an inducer of the metC-cysK operon. Using a random mutagenesis approach, we identified two genes, cmbR and cmbT, involved in regulation of metC-cysK expression. The cmbT gene is predicted to encode a transport protein, but its precise role in regulation remains unclear. Disruption of cmbT resulted in a two- to threefold reduction of metC-cysK transcription. A 5.7-kb region containing the cmbR gene was cloned and sequenced. The encoded CmbR protein is homologous to the LysR family of regulator proteins and is an activator of the metC-cysK operon. In analogy to CysB from Escherichia coli, we propose that CmbR requires acetylserine to be able to bind the activation sites and subsequently activate transcription of the metC-cysK operon.
Regulated expression of fibronectin, laminin and related integrin receptors during the early chondrocyte differentiation.

We have investigated the expression and localization of fibronectin, laminin, and their receptors, and we used an in vitro chick chondrocyte differentiation model to define a time hierarchy for their appearance in early chondro-genesis and to determine their role in the cell condensation process. By serum fibronectin depletion/reconstitution, or GRGDSP peptide competition experiments, we show that fibronectin contributes to the initial cell-cell interactions that occur during condensation. In later stages, a down-regulation of both fibronectin and of its alpha5beta1 integrin receptor occur, as demonstrated by mRNA and protein kinetics. Immunolocalisation studies suggest that the reduction of fibronectin in discrete areas is involved in local activation of the cell differentiation program. Furthermore, we show that laminin is expressed during the in vitro cell condensation process in areas that are negative for fibronectin staining. The types of laminin as well as the timing of expression have been determined by northern blot and RT-PCR analyses. The highest levels of expression are coincident with maximal cell aggregation. The alpha3beta1 laminin receptor, highly expressed in dedifferentiated cells, follows later on the ligand trend. During in vitro chondrogenesis, a down-regulation in the B isoform, and an up-regulation of the A isoform, of the alpha subunit of the alpha6beta1 laminin receptor occurs. Immunolocalisation studies suggest that laminin is involved in the definition of differentiating areas as opposed to non differentiating areas of the condensed region, i.e. the periphery, which eventually gives rise to the perichondrium.
Synthesis ranking with critic resonance

The existing literature on social choice and the theory of ranking has been particularly fruitful in applications to web search and online social networks. In addition, related techniques have been used to rank the importance of reviewers and critics on the web, by assigning weights associated with attributes such as influence, reach, status, or trust values. In applications of user opinion and preference data analysis, it should be considered paradoxical if users or critics with high weight values reflect opinions and preferences seen to be independent of, or in conflict with, the aggregate ranking of items. If rankings do not resonate, then that is an indication of inconsistencies, and thus the schemes used to determine rankings may need to be modified. In this paper we present a new theoretical and algorithmic framework for formally investigating resonance between aggregate rankings of items and ratings of critics. In particular, we develop a new paradigm called synthesis ranking, which entails synthesizing an aggregate ranking and critic weighting scheme by computing resonant equilibrium points. In addition, we present an efficient, iterative technique called entrainment for computing resonant equilibrium points. Further we show that the synthesis framework can incorporate natural critic weighting attributes. Finally, we present a redundancy paradox that demonstrates support for a ranking model that uses critic weights.
Acoustic feedback cancellation for long acoustic paths using a nonstationary source model

While several proactive acoustic feedback (Larsen-effect) cancellation schemes have been presented for speech applications with short acoustic feedback paths as encountered in hearing aids, these schemes fail with the long impulse responses inherent to, for instance, public address systems. We derive a new prediction error method (PEM)-based scheme (referred to as PEM-AFROW) which identifies both the acoustic feedback path and the nonstationary speech source model. A cascade of a short- and a long-term predictor removes the coloring and periodicity in voiced speech segments, which account for the unwanted correlation between the loudspeaker signal and the speech source signal. The predictors calculate row operations which are applied to prewhiten the speech source signal, resulting in a least squares system that is solved recursively by means of normalized least mean square or recursive least squares algorithms. Simulations show that this approach is indeed superior to earlier approaches whenever long acoustic channels are dealt with
An Integrated Logic for Termination and Non-Termination Reasoning

We propose a logical framework for specifying and proving assertions about program termination and non-termination. Although program termination has been well studied, it is usually added as an external component to a specification logic. Here we propose to integrate termination requirements directly into our specification logic, as temporal constraints for each execution phase of every method. Our temporal constraints can specify a strict decrease in some bounded measure for termination proofs or the unreachability of method exit for nontermination proofs. The reasoning on these temporal constraints is supported by a novel temporal entailment procedure. Furthermore, our termination-enhanced logic can leverage on richer specification logics to help conduct more intricate termination reasoning for programs with heap manipulation or multiple terminating phases. Through a seamless integration into the specification logics, we expect our termination reasoning to benefit from any future improvements to our logics, and vice-versa. With an experimental evaluation, we report on the usability and practicality of our approach for capturing both termination and non-termination reasoning for an existing verification system.
Enhanced Specifications for Web Service Composition

The service-oriented computing research community has devoted a great deal of attention to Web service specification, discovery and composition. The ability to efficiently select and compose services in order to accomplish a complex user goal is of utmost importance. However, the problem of on-demand composition still lacks satisfactory solutions for the case of complex services intending to serve non-elementary goals and adhering to constraints. Current service specification proposals include definitions of pre-and post-conditions, i.e., conditions that must be satisfied in the state prior to and after the enactment of the service. However, due to the need for complex compositions, conditions and constraints that do not exist in the individual service specifications arise. For the definition of these conditions, we augment service specifications with invariants and demonstrate how such assertions can be exploited for determining service effects and compositionality