Frequency Weighting Research Articles

Optimal tuning of H∞ fixed‐structure robust controller against multiple high‐level requirements using evolutionary computation

SummaryThis work deals with the optimal controller synthesis against high‐level multiple requirements using evolutionary computation. Indeed, such stochastic algorithms are interesting to solve problems based on complex industrial specifications and so seem to be particularly well suited to optimal robust controller synthesis. Using the H∞ loop‐shaping framework, the optimal weights/controller tuning without any structural assumption (in terms of poles/zeros/damping) on the searched filters (except of course their order) is investigated. The absence of such any structural assumption is important to avoid affecting the quality of the solution toward a complex specification and allows reducing the synthesis problem to a simple one with static scalings in place of frequency weights. Using a version of differential evolution algorithm well adapted for high dimensional control problems, computing directly a fixed‐structure controller for complex industrial specifications toward a generic nonconstraint fitness with quite reasonable computing time is achieved. The illustrating example deals with the line‐of‐sight stabilization problem.

A double-blind, randomized, placebo-controlled clinical trial evaluating the safety and efficacy of autologous muscle derived cells in female subjects with stress urinary incontinence.

The purpose of the study was to assess safety and efficacy of autologous muscle derived cells for urinary sphincter repair (AMDC-USR) in female subjects with predominant stress urinary incontinence. A randomized, double-blind, multicenter trial examined intra-sphincteric injection of 150 × 106 AMDC-USR versus placebo in female subjects with stress or stress predominant, mixed urinary incontinence. AMDC-USR products were generated from vastus lateralis needle biopsies. Subjects were randomized 2:1 to receive AMDC-USR or placebo and 1:1 to receive 1 or 2 treatments (6months after the first). Primary outcome was composite of ≥ 50% reduction in stress incontinence episode frequency (IEF), 24-h or in-office pad weight tests at 12months. Other outcome data included validated subject-recorded questionnaires. Subjects randomized to placebo could elect to receive open-label AMDC-USR treatment after 12months. Subject follow-up was up to 2years. AMDC-USR was safe and well-tolerated with no product-related serious adverse events or discontinuations due to adverse events. Interim analysis revealed an unexpectedly high placebo response rate (90%) using the composite primary outcome which prevented assessment of treatment effect as designed and thus enrollment was halted at 61% of planned subjects. Post hoc analyses suggested that more stringent endpoints lowered placebo response rates and revealed a possible treatment effect. Although the primary efficacy finding was inconclusive, these results inform future trial design of AMDC-USR to identify clinically meaningful efficacy endpoints based on IEF reduction, understanding of placebo response rate, and refinement of subject selection criteria to more appropriately align with AMDC-USR's proposed mechanism of action.

An assessment of using frequency weights for record linkage

Many different techniques can be used to perform entity-to-entity record linkage. The optimal approach may relate to the entity type, such as individual or establishment, and source, such as sample survey, enumeration, program administration, or register. Within the Fellegi-Sunter record linkage framework, the frequency of occurrence of match variables’ values can be either employed or ignored when estimating the probabilities from which the match weights are derived. Namely, the U-probability that a variable agrees in a pair of non-matched records, is estimated for each value of a match variable in the frequency-based approach, or in general in the non-frequency-based approach. The aim of this talk is to compare the quality of results produced by the frequency-based and non-frequency-based approaches when linking a household survey and an establishment survey to vital records. A household survey, the National Health Interview Survey (NHIS) and an establishment survey, the National Hospital Care Survey (NHCS) are each linked to the National Death Index (NDI) using the Fellegi-Sunter record linkage framework. We perform the linkage on each survey twice; first, employing frequency-based weights for all match variables, and second, simple agree/disagree weights for all match variables. We then examine any differences in quality within each survey, and assess whether any differences in the quality of the two approaches are attributable to the type of survey, household versus establishment.

Practical implementation of auditory time and frequency weighting in marine bioacoustics

Much effort is currently directed at describing the behavioral reactions of marine mammals following exposure to sound with the aim of deriving generalized thresholds and dose-response functions. The perceived loudness of a given sound is a candidate for a common metric for sound exposure. The loudness of a signal relates to various factors, including the stimulus duration and frequency content, and it can be approximated by an appropriate time and frequency weighting of the signal. Auditory frequency weighting is achieved by applying a frequency weighting function (band-pass filter), with a frequency response resembling the shape of an inverted audiogram. Temporal weighting may be achieved by computing the running rms-average (Leq) with a time constant that is comparable to that of the mammalian auditory system. The practical implementation of such weighting functions are presented in the form of Matlab functions. These functions generate output signals that are weighted according to current recommendations for different groups of marine mammals. With these functions, it is possible to derive the weighted peak Leq of a signal, which is likely to be a good proxy for the loudness of the signal. Ultimately, this weighted level is conjectured to be a predictor of behavioral response of marine mammals to the sound.

Design water demand of irrigation for a large region using a high-dimensional Gaussian copula

Abstract. Spatial and frequency distributions of precipitation should be considered in determining design water demand of irrigation for a large region. In Guangdong Province, South China, as a study case, an eight-dimensional joint distribution of precipitation for agricultural sub-regions was developed. A design procedure for water demand of irrigation for a given frequency of precipitation of the entire region was proposed. Water demands of irrigation in the entire region and its sub-regions using three design methods, i.e., equalized frequency (EF), typical year (TY) and most-likely weight function (MLW), were compared. Results demonstrated that the Gaussian copula efficiently fitted the high-dimensional joint distribution of eight sub-regional precipitation values. The Kendall frequency was better than the conventional joint frequency to analyze the linkage between the frequency of precipitation of the entire region and individual sub-regions. For given frequencies of precipitation of the entire region, design water demands of irrigation of the entire region among the MLW, EF and TY methods slightly differed, but those of individual sub-regions of the MLW and TY methods fluctuated around the demand lines of the EF method. The alterations of design water demand in sub-regions were more complicated than those in the entire region. The design procedure using the MLW method in association with a high-dimensional copula, which simulated individual univariate distributions, captured their dependences for multi-variables, and built a linkage between regional frequency and sub-regional frequency of precipitation, is recommended for design water demand of irrigation for a large region.

Risk assessment of vascular disorders by a supplementary hand-arm vascular weighting of hand-transmitted vibration.

To provide an updated epidemiological validation for a supplementary method for assessing the risk of vascular disorders from hand-transmitted vibration. The occurrence of vibration-induced white finger (VWF) in the vibration-exposed workers of the Italian cohort of the EU VIBRISKS study was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting Wh defined in international standard ISO 5349-1:2001 [Ah(8) in ms- 2] or the hand-arm vascular frequency weighting Wp proposed in the ISO technical report (TR) 18570:2017 [Ap(8) in ms- 2]. To estimate a threshold value for vascular hand-arm vibration risk, the Wp-weighted vibration exposure value Ep,d (in ms- 1.5) was calculated according to the ISO/TR document. The difference in the predictions of VWF between the exposure measures calculated with the frequency weightings Wh or Wp was investigated by means of logistic modelling. Measures of daily vibration exposure constructed with the frequency weighting Wp [Ap(8) and Ep,d], which gives more importance to intermediate- and high-frequency vibration, were better predictors of the occurrence of VWF in the vibration-exposed workers than the metric derived from the conventional ISO frequency weighting Wh [Ah(8)]. There was some epidemiological evidence for a threshold value of Ep,d for the onset of VWF in the vibration-exposed workers. Measures of daily vibration exposure evaluated with the vascular weighting Wp performed better for the predictions of VWF than those obtained with the frequency weighting Wh recommended in ISO 5349-1.

New Multi-Keyword Ciphertext Search Method for Sensor Network Cloud Platforms.

This paper proposed a multi-keyword ciphertext search, based on an improved-quality hierarchical clustering (MCS-IQHC) method. MCS-IQHC is a novel technique, which is tailored to work with encrypted data. It has improved search accuracy and can self-adapt when performing multi-keyword ciphertext searches on privacy-protected sensor network cloud platforms. Document vectors are first generated by combining the term frequency-inverse document frequency (TF-IDF) weight factor and the vector space model (VSM). The improved quality hierarchical clustering (IQHC) algorithm then generates document vectors, document indices, and cluster indices, which are encrypted via the k-nearest neighbor algorithm (KNN). MCS-IQHC then returns the top-k search result. A series of experiments proved that the proposed method had better searching efficiency and accuracy in high-privacy sensor cloud network environments, compared to other state-of-the-art methods.

Subjective and objective rating of the sound insulation of residential building façades against road traffic noise.

Sound insulation in a building façade plays a key role in the control of road-traffic noise. Façade performance can be described using various internationally standardized single-number quantities (SNQs) with different frequency weightings. The purpose of this study was to evaluate how 25 different SNQs explain the subjective ratings of spectrally different road-traffic sounds transmitted through a façade. Forty-three participants took part in a psychoacoustic laboratory experiment. The task was to evaluate five spectrally different road-traffic sound types transmitted through 12 simulated façade constructions. The participants rated both the loudness and the annoyance of 60 sounds. The playback levels were between 12 and 46 dB LAeq, covering the essential range of road-traffic noise usually measured inside residential dwellings. Linear correlations were determined between the SNQ values of the façades and the subjective ratings. Rw + C50-3150 explained the subjective ratings best when the five sound types were equally considered. It was also the most suitable SNQ for the standard road-traffic spectrum of ISO 717-1. The results of this study can be useful in the development of future standards.

Abstract 4468: Repression of CD44 expression by p53 in a breast cancer progression model

Abstract CD44 is an important molecule in breast cancer. Although CD44 lacks its own signaling domain, it can associate with and co-stimulate signaling by a number of growth factor receptors, such as Her2 and EGF receptor 1. Knockdown of CD44 significantly reduces mammary tumor-initiating frequency and tumor weight. Disruption of tumor cell surface CD44 function induces apoptosis in metastatic mammary carcinoma cells in vivo. Some studies showed that the breast cancer stem cells are enriched in the CD44highCD24low population. The tumor suppressor p53 is mutated or functionally inactivated in over 70% of cancer. In breast cancer, p53 is mutated in ~35% cases, and ~50% breast cancers contain MDM2 or MDMX overexpression. A previous study showed that p53 repressed the expression of CD44 and that this activity was essential for the tumor-suppressor function of p53. We find that p53 potently represses the expression of CD44 in normal human breast epithelial cells. Mutation of the p53 binding site on the CD44 promoter greatly reduces the ability of p53 to repress CD44 expression. We show that p53 repression of CD44 expression is progressively reduced in a breast cancer progression model. Our ongoing studies are elucidating the underlying mechanisms. Our findings will help for better understanding and treatment of breast cancer. Citation Format: Fang Liu, Zhengxue Liu, Guannan Wang, Tanima Roy-Kundu, Isao Matsuura. Repression of CD44 expression by p53 in a breast cancer progression model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4468.

Spectral Kurtosis를 이용한 프로펠러 날개끝 보텍스 소음의 발생위치추정

One primary concern for marine propeller design is the incipient tip vortex cavitation. The present study elaborates its hyperbolic localization, which is subjected to an estimation of time difference of arrival between measured acoustic signals. The generalized cross-correlation with phase transform, a conventional algorithm for time delay estimation, tends to be susceptible to the noise outside the frequency band of signal. In order to suppress these effects, we propose a weighting function, resembling the rectangular window in frequency domain. By further noting that the signal arisen by the tip vortex cavitation can be fall into the cyclostationary type, the spectral kurtosis is employed to design the optimum band of the frequency weights. Finally, the method is verified by experimental measurements in the water tunnel.

The Effect of Sapodilla Leaves (Achras Zapota) Infusum towards Mice (Mus Muculus) Diarrheal Activity Induced by Oleum Ricini

Introduction: Diarrhea is a significant health problem, especially in countries with low income. In many cases, diarrhea even can cause death. Treatment for diarrhea has been done both pharmacologically (including the usage of herbal remedies) and non-pharmacologically. Decoction of the sapodilla’s leaves is often used to treat diarrhea, but no studies directly demonstrates the effects of sapodilla’s leaves’ decoction towards living creatures. The purpose of this study was to determine the effect of sapodilla leaves’ (Achras zapota) infusum towards diarrheal activity of mice (Mus musculus) which can be seen through the onset and frequency of diarrhea, and the consistency and quantity / weight of feces.Methods: 30 mice were divided into five groups. Negative controls (group I) were administered with oleum Ricini, positive controls (group II) were administered with oleum Ricini and Loperamide HCl after half-an hour, and group III, IV, and V, were administered with oleum Ricini and sapodilla leaves’ (Achras zapota) infusum ( with the concentration of 5 g %, 10 g %, and 20 g %) after half-an hour. Then, those mice were observed for 3 hours for their diarrheal activity (diarrheal onset, frequency, fecal consistency, and fecal weights).Results: Analysis by Kruskal-Wallis method showed significant differences of diarrheal activities among the five groups (p = 0.023). Whilst, analysis by Mann-Whitney method showed significant differences between group I and II (p = 0.04), group I and III (p = 0.012), and group I and IV (p = 0.006).Conclusions: Based on the result showed sapodilla leaves’ (Achras zapota) infusum could reduce diarrheal activity of mice (Mus musculus).

Robustness evaluation and robust design for proportional-integral-plus control

ABSTRACTProportional-integral-plus (PIP) control provides a logical extension to conventional two- or three-term (proportional-integral-derivative) industrial control, with additional dynamic feedback and input compensators introduced when the process has second order or higher dynamics, or time delays. Although PIP control has been applied in a range of engineering applications, evaluation of closed-loop robustness has generally relied on empirical methods. In the present article, expressions for the norm of two commonly used PIP control implementations, the feedback and forward path forms, are used, for the first time, to quantify closed-loop robustness. It is shown that the forward path form is not robust for unstable plants. Additional expressions for the norm that encompass frequency weightings of generalised disturbance inputs are also determined. Novel analytical expressions to minimise the norm are derived for the simplest plant, while simulation results based on numerical optimisation are provided for higher order examples. We show that, for certain plants, there are (non-unique) sets of PIP control gains that minimise the norm. The norm is introduced in these cases to determine the controller that balances performance with robustness. Finally, the norm is used as a design parameter for a practical example, namely control of airflow in a 2 m by 1 m by 1 m forced ventilation chamber. The performance of the new PIP controller is compared to previously developed PIP controllers based on pole placement and linear quadratic design.

Patent Keyword Extraction for Sustainable Technology Management

Recently, sustainable growth and development has become an important issue for governments and corporations. However, maintaining sustainable development is very difficult. These difficulties can be attributed to sociocultural and political backgrounds that change over time [1]. Because of these changes, the technologies for sustainability also change, so governments and companies attempt to predict and manage technology using patent analyses, but it is very difficult to predict the rapidly changing technology markets. The best way to achieve insight into technology management in this rapidly changing market is to build a technology management direction and strategy that is flexible and adaptable to the volatile market environment through continuous monitoring and analysis. Quantitative patent analysis using text mining is an effective method for sustainable technology management. There have been many studies that have used text mining and word-based patent analyses to extract keywords and remove noise words. Because the extracted keywords are considered to have a significant effect on the further analysis, researchers need to carefully check out whether they are valid or not. However, most prior studies assume that the extracted keywords are appropriate, without evaluating their validity. Therefore, the criteria used to extract keywords needs to change. Until now, these criteria have focused on how well a patent can be classified according to its technical characteristics in the collected patent data set, typically using term frequency–inverse document frequency weights that are calculated by comparing the words in patents. However, this is not suitable when analyzing a single patent. Therefore, we need keyword selection criteria and an extraction method capable of representing the technical characteristics of a single patent without comparing them with other patents. In this study, we proposed a methodology to extract valid keywords from single patent documents using relevant papers and their authors’ keywords. We evaluated the validity of the proposed method and its practical performance using a statistical verification experiment. First, by comparing the document similarity between papers and patents containing the same search terms in their titles, we verified the validity of the proposed method of extracting patent keywords using authors’ keywords and the paper. We also confirmed that the proposed method improves the precision by about 17.4% over the existing method. It is expected that the outcome of this study will contribute to increasing the reliability and the validity of the research on patent analyses based on text mining and improving the quality of such studies.

Classification images for localization performance in ramp-spectrum noise.

This study investigates forced localization of targets in simulated images with statistical properties similar to trans-axial sections of x-ray computed tomography (CT) volumes. A total of 24 imaging conditions are considered, comprising two target sizes, three levels of background variability, and four levels of frequency apodization. The goal of the study is to better understand how human observers perform forced-localization tasks in images with CT-like statistical properties. The transfer properties of CT systems are modeled by a shift-invariant transfer function in addition to apodization filters that modulate high spatial frequencies. The images contain noise that is the combination of a ramp-spectrum component, simulating the effect of acquisition noise in CT, and a power-law component, simulating the effect of normal anatomy in the background, which are modulated by the apodization filter as well. Observer performance is characterized using two psychophysical techniques: efficiency analysis and classification image analysis. Observer efficiency quantifies how much diagnostic information is being used by observers to perform a task, and classification images show how that information is being accessed in the form of a perceptual filter. Psychophysical studies from five subjects form the basis of the results. Observer efficiency ranges from 29% to 77% across the different conditions. The lowest efficiency is observed in conditions with uniform backgrounds, where significant effects of apodization are found. The classification images, estimated using smoothing windows, suggest that human observers use center-surround filters to perform the task, and these are subjected to a number of subsequent analyses. When implemented as a scanning linear filter, the classification images appear to capture most of the observer variability in efficiency (r2 = 0.86). The frequency spectra of the classification images show that frequency weights generally appear bandpass in nature, with peak frequency and bandwidth that vary with statistical properties of the images. In these experiments, the classification images appear to capture important features of human-observer performance. Frequency apodization only appears to have a significant effect on performance in the absence of anatomical variability, where the observers appear to underweight low spatial frequencies that have relatively little noise. Frequency weights derived from the classification images generally have a bandpass structure, with adaptation to different conditions seen in the peak frequency and bandwidth. The classification image spectra show relatively modest changes in response to different levels of apodization, with some evidence that observers are attempting to rebalance the apodized spectrum presented to them.

Supervised topic models with weighted words: multi-label document classification

Supervised topic modeling algorithms have been successfully applied to multi-label document classification tasks. Representative models include labeled latent Dirichlet allocation (L-LDA) and dependency-LDA. However, these models neglect the class frequency information of words (i.e., the number of classes where a word has occurred in the training data), which is significant for classification. To address this, we propose a method, namely the class frequency weight (CF-weight), to weight words by considering the class frequency knowledge. This CF-weight is based on the intuition that a word with higher (lower) class frequency will be less (more) discriminative. In this study, the CF-weight is used to improve L-LDA and dependency-LDA. A number of experiments have been conducted on real-world multi-label datasets. Experimental results demonstrate that CF-weight based algorithms are competitive with the existing supervised topic models.

Influência da intervenção sensório-motora no sistema respiratório de recém-nascidos prematuros

Introduo: A interveno sensrio-motora utilizada para prevenir ou minimizar alteraes no desenvolvimento de recm-nascido pr-termo (RNPT). Entretanto, mais estudos sobre sua influncia em RNPT hospitalizados so necessrios. Objetivos: Verificar a influncia da interveno sensrio-motora sobre parmetros fisiolgicos e peso corporal em RNPT hospitalizados. Mtodos: Avaliaram-se 30 RNPT estveis, submetidos a uma interveno sensrio-motora durante 10 minutos dirios por 3 dias consecutivos. Anlises comparativas foram realizadas considerando as variveis frequncia respiratria (FR), frequncia cardaca (FC), saturao de oxignio (SaO2), Boletim Silverman-Andersen (BSA) e peso corporal, mensuradas imediatamente antes da interveno, imediatamente aps, e no 15 minuto aps trmino da interveno. Resultados: A FR foi maior no 15 minuto aps a interveno do que antes (p0,05). A SaO2 aumentou logo aps a interveno (p0,05). O peso corporal aumentou ao longo dos trs dias (p0,001). A FC e o BSA permaneceram constantes. Concluso: A interveno sensrio-motora pode ter contribudo para melhor frequncia respiratria e saturao de oxignio e demonstrou-se segura aos RNPT.

Hyperbolic localization of incipient tip vortex cavitation in marine propeller using spectral kurtosis

Abstract Incipient tip vortex cavitation is one of the primary concerns for propeller design in commercial- or naval- vessels. This paper attempts its hyperbolic localization, which should be preceded by accurate estimation of time delay between measured acoustic signals. Although the generalized cross-correlation with phase transform can be considered as a conventional algorithm for time delay estimation, it is prone to be vulnerable to the noise dwelling outside the frequency band of signal. In order to nullify these noise effects, a weighting function, resembling the rectangular window in frequency domain, is introduced. By further noting that the signal arisen by the tip vortex cavitation can be categorized into the cyclostationary type, the spectral kurtosis is adhered to design the optimum band of the frequency weights. Finally, the proposed method is shown to be valid by two experimental demonstrations of artificial source and propeller cavitation.

Removal of tetracycline antibiotics from wastewater by pulsed corona discharge plasma coupled with natural soil particles

In this study, pulsed corona discharge plasma coupled with natural soil particles (PCDP/SPs) were used to remove tetracycline hydrochloride (TCH) from wastewater. The differences among three typical and natural soil particles (SPs, black soil (BS) of Jilin, loess soil (LS) of Shaanxi, and red soil (RS) of Hunan in China) for TCH removal were compared by the PCDP/SPs system. The energy yields upon TCH removal and synergistic effects between the pulsed corona discharge plasma (PCDP) and SPs were analyzed. The effects of various factors on removal efficiency of TCH were investigated. The results indicated that the removal efficiency of TCH and the energy yield of PCDP were obviously improved in the PCDP/SPs system. Different SPs types had significant effects on the TCH removal. The removal efficiencies of TCH in the PCDP/SPs system with LS and BS were higher than that in the PCDP/SPs system with RS. The removal efficiency of TCH increased with an increase in the pulsed peak voltage, pulsed frequency, and SPs weight and a decrease in the SPs size. The removal efficiency of TCH decreased upon increasing the initial concentration of TCH and solution conductivity. The recycling experiment showed that the removal efficiency of TCH still maintained a high level after four cycles in the PCDP/LS system; however, a decrease in the removal efficiency of TCH was also observed. The consumption of active species in solution demonstrated that OH and O3 play key roles in TCH degradation. Intermediates in the process of TCH degradation for the PCDP/SPs system with LS were identified by GC–MS, and a possible degradation pathway was also proposed.

Dynamic Characteristics of Green Sandstone Subjected to Repetitive Impact Loading: Phenomena and Mechanisms

A split Hopkinson pressure bar apparatus driven by a pendulum hammer was used to perform uniaxial compression tests to examine the degradation process of green sandstone subjected to repetitive impact loading. The acoustic characteristics, dissipated energy, deformation characteristics, and microstructure evolution were investigated. The representative stress–strain curve can be broken into five stages that were characterized by changes in the axial strain response during impact loading. Both the ultrasonic wave velocity and cumulative dissipated energy exhibited obvious three-stage behavior with respect to the impact number. As the impact number increased, more than one peak was observed in the frequency spectra, and the relative weight of the peak frequency increased in the low-frequency range. According to the evolution of the ultrasonic wave velocity, the degradation process was divided into three stages. By comparing the intact stage I and early stage II microcrack development patterns, the initiation of new cracks and elongation of existing cracks were identified as the main degradation mechanisms. Furthermore, a slight increase in the number of cracks was observed, and microcrack lengths steadily increased. Moreover, due to the low level of microcrack damage, the deformation mechanism was mainly characterized by volume compression during impact loading. In late stage II, the main degradation mechanism was the elongation of existing cracks. Additionally, as microcracks accumulated in the rock samples, cracks were arranged parallel to the loading direction, which led to volume dilation. In stage III, microcracks continued to elongate nearly parallel to the loading direction and then linked to each other, which led to intense degradation in the rock samples. In this stage, rock sample deformation was mainly characterized by volume dilation during impact loading. Finally, rock samples were split into blocks with fractures oriented subparallel to the loading direction. These results can improve the understanding of the stability evaluations of rock structures subjected to repetitive impact loading.

GCC-PHAT time difference estimation algorithm based on binary frequency weight with suppressing wind noise

GCC-PHAT time difference estimation algorithm based on binary frequency weight with suppressing wind noise