Incremental Frequency Research Articles

An Improved System for Sentence-level Novelty Detection in Textual Streams

Novelty detection in news events has long been a difficult problem. A number of models performed well on specific data streams but certain issues are far from being solved, particularly in large data streams from the WWW where unpredictability of new terms requires adaptation in the vector space model. We present a novel event detection system based on the Incremental Term Frequency-Inverse Document Frequency (TF-IDF) weighting incorporated with Locality Sensitive Hashing (LSH). Our system could efficiently and effectively adapt to the changes within the data streams of any new terms with continual updates to the vector space model. Regarding miss probability, our proposed novelty detection framework outperforms a recognised baseline system by approximately 16% when evaluating a benchmark dataset from Google News.

Cluster-discovery of Twitter messages for event detection and trending

Social media data carries abundant hidden occurrences of real-time events. In this paper, a novel methodology is proposed for detecting and trending events from tweet clusters that are discovered by using locality sensitive hashing (LSH) technique. Key challenges include: (1) construction of dictionary using incremental term frequency–inverse document frequency (TF–IDF) in high-dimensional data to create tweet feature vector, (2) leveraging LSH to find truly interesting events, (3) trending the behavior of event based on time, geo-locations and cluster size, and (4) speed-up the cluster-discovery process while retaining the cluster quality. Experiments are conducted for a specific event and the clusters discovered using LSH and K-means are compared with group average agglomerative clustering technique.

Passive and Adaptive Damping Systems for Vibration Mitigation and Increased Fatigue Service Life of a Tied Arch Railway Bridge

AbstractIn this article, the use of external damping systems for vibration mitigation of railway bridge dynamics is studied. For a presented case study bridge, the performance of different tuned mass damper systems (TMDs) is studied. During train passage, the change in dynamic characteristics of the bridge may produce a significant detune to a passive TMD. Therefore, routines for a variable stiffness TMD using incremental frequency estimates are developed. Based on numerical simulations, the cumulative fatigue damage is calculated for different damper systems. Due to resonant behavior, the results are found to highly depend on the train speed. Based on an assumed probability density function for the train speed, fragility curves are produced to express the probability of fatigue failure as a function of the number of train passages.

Development of Locally Resonant Structures for Sonic Barriers

The application of metamaterials or structured material principles to sound insulation has produced a new isolation concept known as locally resonant structures (LRS). LRS combine interacting components specifically arranged to generate localised resonances within the structure. LRS have exceptional sound transmission loss (TL) performance in defined frequency bands, which can be tailored for any desired region of the spectrum. Low frequency noise (below 1 kHz) is where irritating acoustic intrusion frequently occurs but is both challenging and expensive to prevent with conventional solutions, and where the LRS is a potentially compact and relatively lightweight solution. Numerical models based on networks of single-degree of freedom oscillators were used to understand how the components of the LRS can be manipulated to generate a designated TL performance spectrum. Designs with the desired TL characteristics were then modelled using FEA software, and samples were fabricated for testing. This paper will focus on results obtained by testing the LRS samples in an impedance tube adapted for TL experimentation. These results showed that the highest performing network arrangements combined layers of multiple resonators with incremental resonant frequencies to increase system bandwidth. Experimental data for various LRS arrangements shows good correspondence to modelling predictions. Samples yielded systems with attenuation peaks of 80dB over band widths approaching 350 Hz at frequencies well below 1 KHz These results provide insight into the benefits and limitations of complex LRS, and how to use this technology for practical applications.

Integrated 8 × 8 array redox sensor system employing on-chip square wave voltammetric circuit for multi point and high-speed detection

A square wave voltammetric measurement system with an 8 × 8 array of sensing pixels is integrated within a single chip for multi point and high-speed electrochemical analysis. The sensor was designed to operate at 400 ms/frame under the condition of 20 mV and 500 Hz of step increment and square wave frequency, respectively. Peak currents from the 8 × 8 pixel array of potassium ferricyanide were obtained at the potential range from −0.5 to 0.5 V. We also obtained a small variation of the measured concentration result of all 64 pixels under the concentration range from 0.6 to 6 mM of potassium ferricyanide standard solution.

Improved algorithm of thematic term extraction based on increment term-set frequency from Chinese document

In order to solve the problem that the thematic term extraction algorithm based on incremental term-set frequency cannot extract compound-words, this paper added text preprocessing, compound-word recognition, to the original algorithm. Compound-word recognition was based on part-of-speech detection and word co-occurrence directed graph, and corrected the results of segmentation. When generating thematic term candidate set, the position of each word was examined and determined its weight. And then, the total weight of the same word was accumulated, and a candidate set of thematic terms was generated by the weight from high to low. When this algorithm got a term from thematic term candidate set, the increment frequency was calculated. If the increment was less than a given threshold, the algorithm stopped; otherwise, the thematic term candidate was added into thematic term set. The experimental results show this algorithm achieves sound effects,the thematic terms acquired by this algorithm can more aptly reflect the main contents of the article, and the satisfaction of thematic term increased 5% than the original algorithm.

Clinical Drug Resistance Linked to Inter-Convertible Phenotypic and Functional States of Tumor-Propagating Cells in Multiple Myeloma.

AbstractAbstract 2909Unlike the established role of acquired genetic events and bone marrow microenviroment in the pathogenesis of multiple myeloma (MM), the phenotype and function of cells enriched in tumor-propagating activity and their relationship to the phenotypic architecture in MM are controversial. Because the immunoglobulin heavy (IgH) chain class-switched myeloma plasma cell (PC) is the final event of a linear, B cell lineage developmental process, it was suggested that myeloma cell growth is sustained by a minority of cells more immature than the PC. We combined multicolour flow-cytometry and sorting with patient-specific quantitative PCR (qPCR) to dissect the myeloma clonal organisation in the bone marrow (BM) and peripheral blood (PB). In a cohort of 30 patients we show that MM comprises at least four hierarchically organised, clonally-related sub-populations which, although phenotypically distinct, share the same oncogenic chromosomal abnormalities as well as IgH chain complementarity region 3 area sequence. We found rare CD19+ clonotypic cells with phenotype either of resting memory cell (CD19+CD38-IgD-CD27+/−) or plasmablasts (CD19+CD38++CD319+CD138-) and CD19-CD38hiCD319+CD200+CD56+ clonotypic cells, comprising CD138- (∼3% of the clone, termed Pre-PC), CD138low and CD138+ PC. The clonal populations resemble their normal counterparts and exist in nearly logarithmic incremental frequencies in the BM. Using dynamic mathematical models and a Bayesian approach a Pre-PC->PC transition was predicted, outside the linear developmental process. Following intravenous injection of purified clonotypic populations into sub-lethally irradiated NSG mice, we found that both PC (in 9/12 of the injected mice, 75%) and Pre-PC (4/16, 25%) can engraft, but not the CD19+ clonotypic cells (0/10). Of note, upon engraftment both PC and Pre-PC regenerate the original CD19- hierarchy of the human BM, as predicted by mathematical modelling. In addition, Pre-PC are more quiescent and unlike PC, preferentially localize at extramedullary niches, such as the liver and spleen of the engrafted animals. Therefore, the myeloma-propagating activity is the exclusive property of a population characterized by its ability for bi-directional transition between the dominant PC and the low frequency Pre-PC. To gain insights into the molecular mechanisms underpinning this reversible phenotypic transition we used gene expression profiling of highly purified BM Pre-PC and PC (n=9). Differential expression analysis and principal component analysis clearly separate Pre-PC from PC, with 7 of 9 samples following the same expression pattern in hierarchical clustering. Functional annotation analysis using DAVID shows that Pre-PC are enriched in epigenetic regulators, including histone methyl-transferases (belonging to the Polycomb repressive complex 2 or Trithorax MLL activating complex) and de-methylases, histone acetyl-transferases and de-acetylases as well as several members of SWI/SNF chromatin remodeling complex, suggesting that epigenetic plasticity underpins the phenotypic diversification of myeloma-propagating cells. Finally, to study the clinical importance of the myeloma clonal organisation, with emphasis to clinical drug resistance, we prospectively assessed the size of the different phenotypes in paired, pre- and post-treatment BM samples (n=8). We show that in all cases a higher proportion of Pre-PC than PC persisted after treatment suggesting that Pre-PC are clinically more drug-resistant than PC (median 10.3-fold, range 4.4–332, p=0.008). Thus, clinical drug resistance in MM is linked to reversible, bi-directional phenotypic transition of myeloma-propagating cells, likely under the orchestration of epigenetic regulators. These novel biological insights have important clinical implications in relation to assessment of minimal residual disease and development of alternative therapeutic strategies in MM. Disclosures:No relevant conflicts of interest to declare.

Band-gaps in electrostatically controlled dielectric laminates subjected to incremental shear motions

The thickness vibrations of a finitely deformed infinite periodic laminate made out of two layers of dielectric elastomers is studied. The laminate is pre-stretched by inducing a bias electric field perpendicular to the layers. Incremental time-harmonic fields superimposed on the initial finite deformation are considered next. Utilizing the Bloch-Floquet theorem along with the transfer matrix method we determine the dispersion relation which relates the incremental fields frequency and the phase velocity.Ranges of frequencies at which waves cannot propagate are identified whenever the Bloch-parameter is complex. These band-gaps depend on the phases properties, their volume fraction, and most importantly on the electric bias field. Our analysis reveals how these band-gaps can be shifted and their width can be modified by changing the bias electric field. This implies that by controlling the electrostatic bias field desired frequencies can be filtered out. Representative examples of laminates with different combinations of commercially available dielectric elastomers are examined.

Better bounds for incremental frequency allocation in bipartite graphs

We study frequency allocation in wireless networks. A wireless network is modeled by an undirected graph, with vertices corresponding to cells. In each vertex, we have a certain number of requests, and each of those requests must be assigned a different frequency. Edges represent conflicts between cells, meaning that frequencies in adjacent vertices must be different as well. The objective is to minimize the total number of used frequencies.The offline version of the problem is known to be NP-hard. In the incremental version, requests for frequencies arrive over time and the algorithm is required to assign a frequency to a request as soon as it arrives. Competitive incremental algorithms have been studied for several classes of graphs. For paths, the optimal (asymptotic) ratio is known to be 4/3, while for hexagonal-cell graphs it is between 1.5 and 1.9126. For ξ-colorable graphs, the ratio of (ξ+1)/2 can be achieved.In this paper, we prove nearly tight bounds on the asymptotic competitive ratio for bipartite graphs, showing that it is between 1.428 and 1.433. This improves the previous lower bound of 4/3 and upper bound of 1.5. Our proofs are based on reducing the incremental problem to a purely combinatorial (equivalent) problem of constructing set families with certain intersection properties.

Decentralized Load-Frequency Control of Large-Scale Nonlinear Power Systems: Fuzzy Overlapping Approach

This paper develops a design methodology of a decentralized fuzzy load-frequency controller for a large-scale nonlinear power system with valve position limits on governors. The concerned system is locally exactly modeled in Takagi-Sugeno's form. Sufficient design condition for uniform ultimate boundedness of the closed-loop system is derived based on the overlapping decomposition. Convergence of all incremental frequency deviations to zero is also investigated. A simulation result is provided to visualize the effectiveness of the proposed technique.

Low-Complexity Frequency Estimation Using Multiple Disjoint Pilot Blocks in Burst-Mode Communications

Two low-complexity data-aided frequency estimators, suitable for use in burst-mode communications, are described and analyzed. The estimators are based on pilot symbols organized into disjoint blocks embedded in the burst. The first estimator is a generalization of the phase increment frequency estimation technique and the second estimator is a generalization of the autocorrelation frequency estimation technique. The generalizations are needed to account for the spacings between the pilot blocks. It is shown that the frequency estimators exhibit good accuracy while maintaining useful operating ranges.

Desenvolvimento de técnicas micromagnéticas de análise de tensões em risers flexiveis

Em algumas aplicações, a detecção de defeitos não é suficiente para a segurança operacional de componentes e estruturas. Deste modo, as técnicas não destrutivas precisam ser adaptadas para a análise do estado de tensões atuantes no componente. Este trabalho apresenta os esforços despendidos no desenvolvimento de sistemas não destrutivos de análise de tensões, voltados para o monitoramento do estado de tensões atuantes em arames da armadura de tração de Risers flexíveis utilizados para o transporte de petróleo e seus derivados. Combinando técnicas como a Análise Harmônica do Campo Magnético Tangencial, Análise Incremental da Permeabilidade Magnética e Análise Multi-freqüência das Correntes Parasitas os resultados mostraram boa correlação entre os carregamentos aplicados e as medidas micromagnéticas, mostrando a grande aplicabilidade das técnicas magnéticas para a caracterização de materiais de engenharia.

Study of the Effect of Excitation Frequency on Electrode Polarization Impedance-Type Flow Transducer

The polarization impedance-type flow transducer has a very simple construction in the form of four metal electrodes immersed in a conducting liquid flowing through a pipe line. The polarization impedance nonlinearly varies with excitation frequency, current density, and flow rate of the conducting liquid. Therefore, in this paper, an attempt is made to study the effect of excitation frequency on the output of electrode polarization impedance-type flow transducer. Incremental frequency plane analysis of the transducer has been performed, and its characteristic equation has been derived. An experiment is performed to study the effect of excitation frequency, and the experimental results are reported in this paper. The experimental data are found to follow the properties of electrode polarization impedance established by other workers.

The Effect of the Coating Layer and the Doped Ion Concentration on the Dielectric Properties of SiO<sub>2</sub>-PANI Electrorheological Fluid

The silicon dioxide particles are coated by polyaniline (PANI) under low temperature, and the doped ion concentration in PANI was adjusted by ammonia with different pH. The dielectric properties of PANI/SiO2 eletrorheological (ER) fluids are measured by impedance analyzer. The results indicated that the dielectric increment and relaxation frequency of ER fluid were enhanced after surface modification of SiO2, which are positive to the ER effect. Moreover, the pH of ammonia can change the relaxation frequency of ER fluid, which can improve the response ability of ER fluid to electric field.

Power-of-two policies for single-warehouse multi-retailer inventory systems with order frequency discounts

This paper presents power-of-two policies for a single-warehouse multi-retailer system. In this system, discounts on the purchasing cost based on order frequency are given to the warehouse. Models with assumptions analogous to the EOQ environment are discussed for all-unit and incremental order frequency discounts. 94%-effective power-of-two policies are developed for both models. For incremental discounts, a 98%-effective power-of-two policy for a variable base planning period is also derived. For each model, a computational study shows every test problem considered has a power-of-two policy that is over 96% effective. An extension to holding costs that are dependent on the purchasing price is also provided.

Incremental frequency count—a post BWT‐stage for the Burrows–Wheeler compression algorithm

AbstractThe stage after the Burrows–Wheeler transform (BWT) has a key function inside the Burrows–Wheeler compression algorithm as it transforms the BWT output from a local context into a global context. This paper presents the Incremental Frequency Count stage, a post‐BWT stage. The new stage is paired with a run length encoding stage between the BWT and the entropy coding stage of the algorithm. It offers high throughput similar to a Move To Front stage, and at the same time good compression rates like the strong but slow Weighted Frequency Count stage. The properties of the Incremental Frequency Count stage are compared to the Move To Front and Weighted Frequency Count stages by their compression rates and speeds on the Calgary and large Canterbury corpora. Copyright © 2006 John Wiley & Sons, Ltd.

A 155.52 Mbps–3.125 Gbps Continuous-Rate Clock and Data Recovery Circuit

A 155.52 Mbps-3.125 Gbps continuous-rate clock and data recovery (CDR) circuit using the full-rate bang-bang phase detector is presented. A frequency detector is proposed to eliminate the harmonic locking problem even with a wide range of data rates and its theoretical analysis is also discussed. A quadrature divider is also presented to generate the clocks with accurate quadrature phases. This CDR circuit has been realized in a 0.18-/spl mu/m CMOS process and its die area is 1.1/spl times/0.8 mm/sup 2/. It consumes 95 mW at the highest bit rate of 3.125 Gbps. It can recover the NRZ data of a 2/sup 31/-1 PRBS with the bit rate ranging from 155.52 Mbps to 3.125Gbps for the incremental frequency acquisition and the NRZ data of a 2/sup 7/-1 PRBS for the decremental frequency acquisition. All the measured bit error rates are less than 10/sup -12/.

A new type of stochastic fractal for application in subsurface hydrology

Data suggest that many property distributions [ P( x); p = property, x = length] are irregular [d P / d x discontinuous], exhibiting variations on all measurement scales. Logic then leads one to attempt to characterize these distributions through study of their increments or fluctuations [ P( x + L) − P( x)], which results naturally in a statistical approach. Increment frequency distributions for a fixed L that fit the Levy/Gaussian family of probability density functions [PDFs] independent of position [statistically stationary in a spatial sense] have well-defined scaling properties characteristic of what are called self-affine stochastic fractals. Data show that measurements in natural systems display some of the scaling characteristics of this PDF family, but do not agree with theory in many important aspects. For example, increment ln( K) distributions show a consistently non-Gaussian shape for smaller values of L and become more Gaussian as L gets large. Particularly for smaller L, PDF tails display an approximate exponential decay and maintain a finite variance. In many cases they appear to be displaying a continuous change from exponential, or even sub-exponential, to Gaussian behavior with increasing L. Data supporting these observations are presented along with explanations of how the fractal-based concepts arise, both physically and mathematically. This is followed by the presentation and initial analysis of what appears to be a new type of stochastic fractal called fractional Laplace motion that displays more of the features observed in natural sedimentary systems.

Application of impulse oscillometry in cystic fibrosis patients

Impulse oscillometry (IOS) measures the total respiratory system impedance (Z) at incremental frequencies during normal tidal breathing. Our aim was to establish the total respiratory impedance and how IOS measurements relate to conventional lung function indices in patients with cystic fibrosis (CF). Results from spirometry, static lung volumes and IOS (R, X, Z, resonant frequency (FR) and reactance area 5Hz — FR (AX)) were compared in 66 adult CF patients recruited from CF Care Centre of Moscow. Patients had airway obstruction (FEV1 = 57 % pred.), hyperinflation (RV = 253 % pred., FRC = 158 % pred., RV / TLC = 52 %). IOS demonstrated a frequency dependent increase in R (R5 = 173 % pred., R20 = 140 % pred.) and a decrease in X (X5 = –0,23 kPa/L / s) with a shift in FR to higher frequencies (FR = 18 Hz, AX = 1,4 kPa / L). There were significant correlations between FR, X20, R5, R20, AX and conventional lung function indices (FEV1 = – 0,74; 0,78; –0,42; –0,31 and –0,76 respectively). The data indicate that measurement of reactance and FR may reflect the degree of airway obstruction. IOS is an effort independent measurement that could be used in clinical routine especially in patients with severe lung diseases.

Induction of micronuclei in mouse and rat by glycidamide, genotoxic metabolite of acrylamide

Male CBA mice and male Sprague–Dawley rats were treated by i.p. injection of glycidamide (GA), the presumed genotoxic metabolite of acrylamide (AA). GA was obtained through a new way of synthesis. As an endpoint of chromosome damage, micronucleus (MN) induction in erythrocytes was measured. Hemoglobin (Hb) adducts were used as a measure of in vivo dose of GA. GA induced linear dose-dependent increases in adduct levels in both species. Rats exhibit, compared with mice, 30% higher Hb adduct levels per unit of administered amount of GA. The incremental MN frequencies per administered dose of GA in mice showed a linear-quadratic dose-dependent curve. In the rat no positive dose–response relationship was obtained, probably due to toxic effects to the bone marrow. The main result of this study is the finding that after treatment with synthetic GA the MN frequency per unit of the in vivo dose of GA in the mouse is very similar to that obtained in a previous study, where animals were treated with AA and GA as a metabolite. This equality in potency of GA, whether its in vivo dose is established by injection of synthetic GA or through metabolism of AA, supports the view that GA is the predominant genotoxic factor in AA exposure.