The Role of Word-Eye-Fixations for Query Term Prediction

Throughout the search process, the user's gaze on inspected SERPs and websites can reveal his or her search interests. Gaze behavior can be captured with eye tracking and described with word-eye-fixations. Word-eye-fixations contain the user's accumulated gaze fixation duration on each individual word of a web page. In this work, we analyze the role of word-eye-fixations for predicting query terms. We investigate the relationship between a range of in-session features, in particular, gaze data, with the query terms and train models for predicting query terms. We use a dataset of 50 search sessions obtained through a lab study in the social sciences domain. Using established machine learning models, we can predict query terms with comparably high accuracy, even with only little training data. Feature analysis shows that the categories Fixation, Query Relevance and Session Topic contain the most effective features for our task

Design and fabrication of polycaprolactone/gelatin composite scaffolds for diaphragmatic muscle reconstruction

Diaphragmatic wall defects caused by congenital disorders or disease remain a major challenge for physicians worldwide. Polymeric patches have been extensively explored within research laboratories and the clinic for soft tissue and diaphragm reconstruction. However, patch usage may be associated with allergic reaction, infection, granulation, and recurrence of the hernia. In this study, we designed and fabricated a porous scaffold using a combination of 3D printing and freeze-drying techniques. A 3D printed polycaprolactone (PCL) mesh was used to reinforcegelatin scaffolds, representing an advantage over previously reported examples since it provides mechanical strength and flexibility. In vitro studies showed that adherent cells were anchorage-dependent and grew as a monolayer attached to the scaffolds. Microscopic observations indicated better cell attachments for the scaffolds with higher gelatin content as compared with the PCL control samples. Tensile testing demonstrated the mechanical strength of samples was significantly greater than adult diaphragm tissue. The biocompatibility of the specimens was investigated in vivo using a subcutaneous implantation method in BALB/c adult mice for 20 days, with the results indicating superior cellular behavior and attachment on scaffolds containing gelatin in comparison to pure PCL scaffolds, suggesting that the porous PCL/gelatin scaffolds have potential as biodegradable and flexible constructs for diaphragm reconstruction

Geostatistical Analyses of Soil Organic Carbon Concentrations in Aligodarz Watershed, Lorestan Province

Introduction: Soil organic carbon (SOC) has great impacts on soil properties, soil productivity, food security, land degradation and global warming. Similar to other soil properties, SOC has a strong spatial heterogeneity as a result of dynamic interactions between parent material, climate and geological history, at both regional and continental scales. However, landscape attributes including slope, aspect, altitude, and land use types are dominant factors influencing on SOC in areas with the same parent materials and climate regime. Understanding and identifying the spatial and temporal distribution of SOC is essential to evaluate soil quality, agricultural management, watershed modeling and soil carbon sequestration budgets. Therefore, the objectives of this study was to estimate soil organic carbon content in the Aligodarz watershed, and to investigate the effects of altitude, slope, and land use type on SOC. Materials and Methods: The research was carried out in the Aligodraz watershed in Lorestan province of Iran. The study area is located between latitudes N 33° 10' 51.72"to N 33° 34' 28.22" and longitudes E 49° 27' 17.99"to E 49° 58' 40.84" 14 that covers an area of 1078.9 km2. It has an altitude between 1866.3 and 3200 m above sea-level. The primary land uses within the watershed include pasture, dryland and irrigated farming. In this study, soil samples were randomly collected from 206 sites at depth of 0– 15 cm during June and August 2003. The mean distance between samples was about 5 km. Soil samples were air-dried in the shade for about 7 days and then passed through a 0.25 mm prior to determination of SOC. Soil organic carbon content was determined in triplicate for each sample using the Walkey-Black method. Basic statistical analyses for frequency distribution, normality tests, Pearson's correlation and analysis of variance were conducted using SPSS (version 18.0). Calculation of experimental variograms and modeling of spatial distribution of SOC were carried out with the geostatistical software GS+ (version 5. 1). Maps were generated by using ILWIS (version 3.3) GIS software. Results and Discussion: The results revealed that the raw SOC data have a long tail towards higher concentrations, whereas that squareroot transformed data can be satisfactorily modelled by a normal distribution. The probability distribution of SOC appeared to be positively skewed and have a positive kurtosis. The square root transformed data showed small skewness and kurtosis, and passed the K–S normality test at a significance level of higher than 0.05. Therefore, the square root transformed data of SOC was used for analyses. The SOC concentration varied from 0.08 to 2.39%, with an arithmetic mean of 0.81% and geometric mean of 0.73%. The coefficient of variation (CV), as an index of overall variability of SOC, was 44.49%. According to the classification system presented by Nielson and Bouma (1985), a variable is moderately varying if the CV is between 10% and 100%. Therefore, the content of SOC in the Aligodarz watershed can be considered to be in moderate variability. The experimental variogram of SOC was fitted by an exponential model. The values of the range, nugget, sill, and nugget/sill ratio of the best-fitted model were 6.80 km, 0.058, 0.133, and 43.6%, respectively. The positive nugget value can be explained by sampling error, short range variability, and unexplained and inherent variability. The nugget/sill ratio of 43.6% showed a moderate spatial dependence of SOC in the study area. The parameters of the exponential smivariogram model were used for kriging method to produce a spatial distribution map of SOC in the study area. The interpolated values ranged between 0.30 and 1.40%. Southern and central parts of this study area have the highest SOC concentrations, while the northern parts have the lowest concentrations of SOC. Kriging results also showed that the major parts of the Aligodarz watershed (about 87%) have statistically SOC content less than 1%. Lower SOC concentrations were associated with high altitude (r = −0.265**). The results of Pearson correlation analysis showed that soil organic carbon content has a significantly negative correlatiton with slope gradient (r = −0.217**). The results also indicated that the SOC content was variable for the different land use types. The irrigated lands had the highest SOC concentrations, while the pasture lands had the lowest SOC values. Conclusion: The square-root transformed data of SOC in Aligodarz watershed of Lorestan province, Iran, followed a normal distribution, with an arithmetic mean of 0.81%, and geometric mean of 0.73%. The coefficient of variation and nugget/sill ratio revealed a moderate spatial dependence of SOC in the study area. The results indicated that the major parts of the Aligodarz watershed have SOC content less than 1%. The land use type had a significant effect on the spatial variability of SOC and that lower SOC concentrations were associated with higher altitude and slope gradients. The irrigated and pasture lands had the highest and lowest SOC concentrations, respectively

Dynamics of an Industrial Power Amplifier for Evaluating Phil Testing Accuracy: An Experimental Approach via Linear System Identification Methods

In power-hardware-in-the-loop (PHIL) digital simulation testing, a power device, also known as device-under-test (DUT), is virtually exchanging power with a power amplifier governed by the reference signals coming from the point of interface (POI) in the power system implemented on a digital real-time simulation platform. Indeed, the power amplifier (also known as grid simulator) is the integral of any PHIL testing, and its dynamics are greatly impacting the accuracy of the PHIL testing. The dynamics of an industrial power amplifier is certainly not an ideal transfer function, i.e., unity. In fact, it is going to degrade the accuracy of the testing especially when the interested frequency range of the power system studies is within the frequency response of the power amplifier\u27s dynamics. Consequently, having an industrial power amplifier\u27s dynamics is very helpful in order to judge the accuracy of the PHIL testing. In this paper, experimental results of an industrial power amplifier have been used, and mathematical linear discrete-time models of the industrial power amplifier have been extracted using different linear system identification methods. Designing input signals, pre-processing data, estimating time delay, estimating model order and parameters, calculating confidence intervals, representing frequency-domain of models, and validating different models are shown in this paper. ARX, ARMAX, BJ, and OE estimated models, which benefit from prediction error method (PEM), are employed in this paper

Data-Driven Cooperative Output Regulation of Multi- Agent Systems via Robust Adaptive Dynamic Programming

This brief studies the cooperative output regulation problems of multi-agent systems with parametric and dynamic uncertainties. By means of robust adaptive dynamic programming, a model-free distributed controller is developed via online input and state data. The cyclic-small-gain theorem is applied to ensure the asymptotic stability of the closed-loop system and thus solves the cooperative output regulation problem. Each follower is able to achieve asymptotic tracking and non-vanishing disturbance rejection. A numerical example is utilized to illustrate the effectiveness of the proposed algorithm

Internal Model Power Synchronization Control of a PV-Based Voltage-Source Converter in Weak-Grid and Islanded Conditions

The power synchronization control strategy for grid-connected voltage-source converters (VSCs) provides an operation similar to synchronous machines. It is able to avoid the instability caused by a standard phase-locked loop in integration into weak grids. However, the non-minimum phase phenomenon in the developed dynamics places a fundamental limitation on the ac system\u27s stability. This paper proposes a one-degree-of-freedom internal-model-based control methodology. It introduces a control approach to incorporate the dynamics of the system\u27s nominal model in the control structure. It also rectifies the unwanted effects of the right-half plane zeros. The explicit incorporation of the model enhances the tracking capabilities of the controller in a PV-based VSC. Besides, this article shows that a single-loop of control will suffice to regulate active and reactive power. Validating results are generated via a hardware-in-the-loop system based on a Xilinx Zynq-7000 SoC field-programmable gate array (FPGA). Furthermore, experimental results are conducted for low-power prototyping to examine the satisfactory performance of the proposed control architecture

Robust Sliding Mode Control of a Three-Phase Grid-Forming Inverter in Non-Ideal Grid Conditions and Isolated Mode of Operation

Grid forming inverters controlled as a virtual synchronous generator can improve the dynamic response of autonomous microgrids. However, the capability of operating in weak grid conditions and isolated mode of operation along with maintaining the voltage at the point of common coupling embodies multiple nonlinear dynamics which can be tackled by a control structure as a discontinuous state function known as sliding mode control. In this paper, a swing equation-based control architecture augmented with a nonlinear sliding mode control has been adopted to design a robust control for a three-phase grid-forming inverter. The proposed control structure can furnish non-oscillatory power to the load during unbalanced grid conditions. This system can operate in isolated mode and sustain the nonlinearities, which can arise due to changes in plant parameters. The performance of the proposed controller is verified through Hardware-in-the-Loop cosimulation results, which confirms the enhanced robustness of such a system