Showing papers by "University of Ljubljana published in 2003"

Theoretical and Empirical Analysis of ReliefF and RReliefF

Abstract: Relief algorithms are general and successful attribute estimators. They are able to detect conditional dependencies between attributes and provide a unified view on the attribute estimation in regression and classification. In addition, their quality estimates have a natural interpretation. While they have commonly been viewed as feature subset selection methods that are applied in prepossessing step before a model is learned, they have actually been used successfully in a variety of settings, e.g., to select splits or to guide constructive induction in the building phase of decision or regression tree learning, as the attribute weighting method and also in the inductive logic programming. A broad spectrum of successful uses calls for especially careful investigation of various features Relief algorithms have. In this paper we theoretically and empirically investigate and discuss how and why they work, their theoretical and practical properties, their parameters, what kind of dependencies they detect, how do they scale up to large number of examples and features, how to sample data for them, how robust are they regarding the noise, how irrelevant and redundant attributes influence their output and how different metrics influences them.

Observation of a Narrow Charmoniumlike State in Exclusive B±→K±π+π-J/ψ Decays

Abstract: We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.

Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet

Abstract: Background: There is a need for better standardization of the dermoscopic terminology in assessing pigmented skin lesions. Objective: The virtual Consensus Net Meeting on Dermoscopy was organized to investigate reproducibility and validity of the various features and diagnostic algorithms. Methods: Dermoscopic images of 108 lesions were evaluated via the Internet by 40 experienced dermoscopists using a 2-step diagnostic procedure. The first-step algorithm distinguished melanocytic versus nonmelanocytic lesions. The second step in the diagnostic procedure used 4 algorithms (pattern analysis, ABCD rule, Menzies method, and 7-point checklist) to distinguish melanoma versus benign melanocytic lesions. κ Values, log odds ratios, sensitivity, specificity, and positive likelihood ratios were estimated for all diagnostic algorithms and dermoscopic features. Results: Interobserver agreement was fair to good for all diagnostic methods, but it was poor for the majority of dermoscopic criteria. Intraobserver agreement was good to excellent for all algorithms and features considered. Pattern analysis allowed the best diagnostic performance (positive likelihood ratio: 5.1), whereas alternative algorithms revealed comparable sensitivity but less specificity. Interobserver agreement on management decisions made by dermoscopy was fairly good (mean κ value: 0.53). Conclusion: The virtual Consensus Net Meeting on Dermoscopy represents a valid tool for better standardization of the dermoscopic terminology and, moreover, opens up a new territory for diagnosing and managing pigmented skin lesions. (J Am Acad Dermatol 2003;48:679-93.) J Am Acad Dermatol 2003;48:679-93.

Meso-gamma scale forecasts using the nonhydrostatic model LM

Abstract: ¶The nonhydrostatic model LM was developed for small scale operational predictions. Advances in computer development will give the possibility of operational models of a rather fine scale, which will cover the meso-gamma scale. The LM is currently applied at a scale of 7 km and an increase of the operational resolution to 2.5 km is planned for the next few years. Predictions of such high resolution require to abandon the hydrostatic assumption, which is used with most current operational weather prediction models. The LM was designed to cover all resolutions from 50 m to 50 km with an efficiency making it suitable for operational use. It is a fully elastic model, using second order centred finite differences. The time integration is done using the Klemp–Wilhelmson method, treating the slow modes by a larger time step than the fast modes. The vertical propagation of the fast waves is done implicitly. After describing the design of the LM, this paper gives examples of model predictions at the meso-γ scale. Some results of the current operational application at the resolution 7 km are presented. Deficiencies in the localisation of model generated precipitation are investigated using an idealised bell shaped mountain and applying different resolutions. In this way the convergence to the correct solution can be investigated. From these results it is concluded, that orographic filtering is necessary and the effect of such filtering on precipitation forecasts is investigated. Finally, the prediction of a squall line over northern Germany is shown in order to demonstrate the potential of the model in forecasting the meso-γ scale.

Clarifying the intrapreneurship concept

Abstract: This research contributes to the development of the theory of intrapreneurship by clarifying the intrapreneurship concept. Intrapreneurship is more precisely defined by referring to emergent behavioral intentions and behaviors that are related to departures from the customary ways of doing business in existing organizations. The intrapreneurship concept is positioned in the management literature, is contrasted with other similar management concepts and developed as an integrative concept composed of eight distinct, yet related dimensions.

Introduction to foliations and Lie groupoids

Abstract: This book gives a quick introduction to the theory of foliations, Lie groupoids and Lie algebroids. An important feature is the emphasis on the interplay between these concepts: Lie groupoids form an indispensable tool to study the transverse structure of foliations as well as their noncommutative geometry, while the theory of foliations has immediate applications to the Lie theory of groupoids and their infinitesimal algebroids. The book starts with a detailed presentation of the main classical theorems in the theory of foliations then proceeds to Molino's theory, Lie groupoids, constructing the holonomy groupoid of a foliation and finally Lie algebroids. Among other things, the authors discuss to what extent Lie's theory for Lie groups and Lie algebras holds in the more general context of groupoids and algebroids. Based on the authors' extensive teaching experience, this book contains numerous examples and exercises making it ideal for graduate students and their instructors.

Human skin color clustering for face detection

Abstract: Computer vision is one of many areas that wants to understand the process of human functionality and copy that process with the intention to complement human life with intelligent machines. For better human-computer interaction it is necessary for the machine to see people. This can be achieved by employing face detection algorithms, like the one used in the installation "15 Seconds of Fame". This installation unites the areas of modern art and technology. Its algorithm is based on skin colour detection. One of the problems that this and similar algorithms have to deal with is sensitivity to the illumination conditions under which the input image is captured. Hence illumination sensitivity influences face detection results. One of the aspects from which we can observe illumination influence is the choice of proper colour space. Since some colour spaces are designed to eliminate the influence of illumination (brightness) when describing colour of an object, an idea of using such a colour space for skin-colour detection has been considered and some of the methods have been researched and tested.

Quantitative real-time PCR using TaqMan and SYBR Green for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, tetQ gene and total bacteria

Abstract: Accurate quantification of bacterial species in dental plaque is needed for microbiological diagnosis of periodontal diseases. The present study was designed to assess the sensitivity, specificity and quantitativity of the real-time PCR using the GeneAmp Sequence Detection System with two fluorescence chemistries. TaqMan probe with reporter and quencher dye, and SYBR Green dye were used for sources of the fluorescence. Primers and probes were designed for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and total bacteria based on the nucleotide sequences of the respective 16S ribosomal RNA genes. Since spread of antibiotic resistance genes is one of the crucial problems in periodontal therapy, quantitative detection of tetQ gene, which confers resistance to tetracycline, was included in the examination. The detection of P. gingivalis, P. intermedia and A. actinomycetemcomitans was linear over a range of 10-10(7) cells (10-10(7) copies for tetQ gene), while the quantitative range for total bacteria was 10(2)-10(7) cells. Species-specific amplifications were observed for the three periodontal bacteria, and there was no significant difference between the TaqMan and SYBR Green chemistry in their specificity, quantitativity and sensitivity. The SYBR Green assay, which was simpler than TaqMan assay in its manipulations, was applied to the clinical plaque samples. The plaque samples were obtained from eight patients (eight periodontal pockets) before and 1 week after the local drug delivery of minocycline. Although the number of P. gingivalis, P. intermedia and A. actinomycetemcomitans markedly decreased after the antibiotic therapy in most cases, higher copy numbers of the tetQ gene were detectable. The real-time PCR demonstrated sufficient sensitivity, specificity and quantitativity to be a powerful tool for microbiological examination in periodontal disease, and the quantitative monitoring of antibiotic resistance gene accompanied with the antibiotic therapy should be included in the examination.

Tartary buckwheat (Fagopyrum tataricum Gaertn.) as a source of dietary rutin and quercitrin.

Abstract: Two samples of tartary buckwheat (Fagopyrum tataricum Gaertn.) from China and one from Luxembourg were studied by high-performance liquid chromatography (HPLC) to reveal the possibilities of growing tartary buckwheat herb as a possible source of rutin, quercetin, and quercitrin. The content of rutin was determined as up to 3% dry weight (DW) in tartary buckwheat herb. Quercitrin values were in the range of 0.01-0.05% DW. Only traces of quercetin were detected in just some of the samples. Tartary buckwheat seeds contained more rutin (about 0.8-1.7% DW) than common buckwheat seeds (0.01% DW). Rutin and quercetin content in seeds depends on variety and growing conditions. Tartary buckwheat seeds contained traces of quercitrin and quercetin, which were not found in common buckwheat seeds.

Colour spaces: perceptual, historical and applicational background

Abstract: In this paper, we present and overview of colour spaces used in electrical engineering and image processing. We stress the importance of the perceptual, historical and applicational background that led to a colour space. The colour spaces presented are: RGB, opponent-colour spaces, phenomenal colour spaces, CMY, CMYK, TV colour spaces (YUV and YIQ), PhotoYCC, CIE XYZ, Lab and Luv colour spaces.

Observation of the DsJ(2317) and DsJ(2457) in B Decays

Abstract: We report the first observation of the B-->(D) over barD(sJ)(2317) and B-->(D) over barD(sJ)(2457) decays based on 123.8x10(6) B (B) over bar events collected with the Belle detector at KEKB. We observe the D-sJ(2317) decay to D(s)pi(0) and the D-sJ(2457) decay to the D(s)(*)pi(0) and D(s)gamma final states. We also set 90% C.L. upper limits for the decays D-sJ(2317)-->D-s*gamma, D-sJ(2457)-->D-s*gamma, D-sJ(2457)-->D(s)pi(0), and D-sJ(2457)-->D(s)pi(+)pi(-).

A survey of processors with explicit multithreading

Abstract: Hardware multithreading is becoming a generally applied technique in the next generation of microprocessors. Several multithreaded processors are announced by industry or already into production in the areas of high-performance microprocessors, media, and network processors.A multithreaded processor is able to pursue two or more threads of control in parallel within the processor pipeline. The contexts of two or more threads of control are often stored in separate on-chip register sets. Unused instruction slots, which arise from latencies during the pipelined execution of single-threaded programs by a contemporary microprocessor, are filled by instructions of other threads within a multithreaded processor. The execution units are multiplexed between the thread contexts that are loaded in the register sets.Underutilization of a superscalar processor due to missing instruction-level parallelism can be overcome by simultaneous multithreading, where a processor can issue multiple instructions from multiple threads each cycle. Simultaneous multithreaded processors combine the multithreading technique with a wide-issue superscalar processor to utilize a larger part of the issue bandwidth by issuing instructions from different threads simultaneously.Explicit multithreaded processors are multithreaded processors that apply processes or operating system threads in their hardware thread slots. These processors optimize the throughput of multiprogramming workloads rather than single-thread performance. We distinguish these processors from implicit multithreaded processors that utilize thread-level speculation by speculatively executing compiler- or machine-generated threads of control that are part of a single sequential program.This survey paper explains and classifies the explicit multithreading techniques in research and in commercial microprocessors.

NMR evidence for the coexistence of order-disorder and displacive components in barium titanate.

Abstract: A quadrupole coupling induced $^{\mathrm{47}}\mathrm{T}\mathrm{i}$ and $^{\mathrm{49}}\mathrm{T}\mathrm{i}$ satellite background which transforms into well-defined satellite lines below ${T}_{c}$ in the ferroelectric phase has been observed in the cubic phase of an ultrapure ${\mathrm{B}\mathrm{a}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}$ single crystal. The results demonstrate the coexistence of a displacive and order-disorder component in the phase transition mechanism and tetragonal breaking of the cubic symmetry due to biased Ti motion between off-center sites in the paraelectric phase above ${T}_{c}$.

Ethylenediaminedissuccinate as a new chelate for environmentally safe enhanced lead phytoextraction.

Abstract: Using a soil column experiment, we compared the effect of a single dose and weekly additions of ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedissuccinate (EDDS) on the uptake of Pb, Zn, and Cd by Chinese cabbage [Brassica rapa L. subsp. pekinensis (Lour.) Hanelt], and on the leaching of heavy metals through the soil profile. The analysis of plant material revealed that both chelates increased the concentrations of Pb and, to a lesser extent, also of Zn and Cd in the leaves of the test plant. The most effective applications were single doses of 10 mmol EDTA and EDDS kg(-1) soil, which caused the concentrations of Pb in the shoots to increase 94.2- and 102.3-fold, respectively, relative to the control. The same dose of EDTA increased the concentration of Zn and Cd in the leaves 4.3- and 3.8-fold and of EDDS 4.7- and 3.5-fold, respectively. In treatments with weekly additions and lower concentrations of both chelates, EDTA was more effective than EDDS in increasing the plant uptake of Pb. In soil columns treated with weekly additions of 10 mmol kg(-1) EDTA, on average 22.7, 7.0, and 39.8% of initial total Pb, Zn, and Cd in the soil were leached through the soil profile. The same amount of EDDS caused much lower leaching of Pb and Cd--only 0.8 and 1.5% of initial total concentrations. Leaching of Zn, 6.2% of the total concentration, was comparable with the EDTA treatment. A biotest with red clover (Trifolium pratense L.) indicated a greater phytotoxic effect of EDTA than EDDS addition. EDDS was also less toxic to soil fungi, as determined by phospholipid fatty acid (PLFA) analysis, and caused less stress to soil microorganisms, as indicated by the trans to cis PLFA ratio. Chelate addition did not prevent the development of arbuscular mycorrhiza on red clover.

Critical role of leadership in nurturing a knowledge-supporting culture

Abstract: This paper addresses the critical role leadership plays in the implementation and facilitation of knowledge management activities. Leadership is particularly important for organizations willing to ‘evolve’ their culture to a knowledge-supporting culture. Organizational culture has been identified as the main impediment to knowledge activities, and therefore leaders should model the proper behaviors causing culture to evolve in a way that enables and motivates knowledge workers to create, codify, transfer, and use and leverage knowledge. In the literature this leadership behavior is referred to as ‘leading through a knowledge lens’. Leading through a knowledge lens has some special characteristics since it is dealing with knowledge workers having specialized expertise. Leading them can be done only by intellectual power, conviction, persuasion, and interactive dialog. It requires skills that build confidence and engagement. Therefore, leaders should establish trust and commitment that will help the knowledge organization to achieve its knowledge and business goals.

Measurement of Branching Fractions for B→ηcK(*) Decays

Abstract: We report measurements of branching fractions for charged and neutral $B\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}K$ decays where the ${\ensuremath{\eta}}_{c}$ meson is reconstructed in the ${K}_{S}^{0}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$, ${K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$, ${K}^{*0}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, and $p\overline{p}$ decay channels. The neutral ${B}^{0}$ channel is a $CP$ eigenstate and can be used to measure the $CP$ violation parameter $\mathrm{sin} 2{\ensuremath{\varphi}}_{1}$. We also report the first observation of the ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}{K}^{*0}$ mode. The results are based on an analysis of $29.1\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ of data collected by the Belle detector at KEKB.

Efficient Algorithms for Citation Network Analysis

Abstract: In the paper very efficient, linear in number of arcs, algorithms for determining Hummon and Doreian's arc weights SPLC and SPNP in citation network are proposed, and some theoretical properties of these weights are presented. The nonacyclicity problem in citation networks is discussed. An approach to identify on the basis of arc weights an important small subnetwork is proposed and illustrated on the citation networks of SOM (self organizing maps) literature and US patents.

Involvement of sympathetic nerve activity in skin blood flow oscillations in humans

Abstract: We have used the wavelet transform to evaluate the time-frequency content of laser-Doppler flowmetry (LDF) signals measured simultaneously on the surfaces of free microvascular flaps deprived of sympathetic nerve activity (SNA), and on adjacent intact skin, in humans. It was thereby possible to determine the frequency interval within which SNA manifests itself in peripheral blood flow oscillations. The frequency interval from 0.0095 to 2 Hz was examined and was divided into five subintervals: I, approximately 0.01 Hz; II, approximately 0.04 Hz; III, approximately 0.1 Hz; IV, approximately 0.3 Hz; and V, approximately 1 Hz. The average value of the LDF signal in the time domain as well as the mean amplitude and total power in the interval from 0.0095 to 2 Hz and amplitude and power within each of the five subintervals were significantly lower for signals measured on the free flap (P < 0.002). The normalized spectral amplitude and power in the free flap were significantly lower in only two intervals: I, from 0.0095 to 0.021 Hz; and II, from 0.021 to 0.052 Hz (P < 0.05); thus indicating that SNA is manifested in at least one of these frequency intervals. Because interval I has recently been shown to be the result of vascular endothelial activity, we conclude that we have identified SNA as influencing blood flow oscillations in normal tissues with repetition times of 20-50 s or frequencies of 0.02-0.05 Hz.

Direction of coupling from phases of interacting oscillators: an information-theoretic approach.

Abstract: A directionality index based on conditional mutual information is proposed for application to the instantaneous phases of weakly coupled oscillators. Its abilities to distinguish unidirectional from bidirectional coupling, as well as to reveal and quantify asymmetry in bidirectional coupling, are demonstrated using numerical examples of quasiperiodic, chaotic, and noisy oscillators, as well as real human cardiorespiratory data.

Technology transfer through FDI in top-10 transition countries: how important are direct effects, horizontal and vertical spillovers?

Abstract: The paper exploits a large set of more than 8,000 firms for ten advanced transition countries in order to uncover the importance of different channels of technology transfer through FDI and its impact on productivity growth of local firms. In addition to direct effects, we also distinguish between intra-industry (horizontal) and inter-industry (vertical) spillovers from foreign owned firms to local firms. After correcting for foreign investment selection bias and controlling for endogeneity of input demand (using a dynamic system GMM approach), direct FDI effects were found to provide by far the most important productivity effect for local firms in transition countries. Direct effects of FDI are found to provide on average an impact on firm's productivity that is larger by factor 50 than the impact of backward linkages and by factor 500 larger than the impact of horizontal spillovers.