Comprehensive comparison of daily IMERG and GSMaP satellite precipitation products in Ardabil Province,Iran

The measurement of precipitation is essential for most environmental studies such as drought monitoring, watershed operations, water hazard management, etc. Development of satellite products has improved their applicability in environmental modelling and could proffer an alternative to gauge-based precipitation data, particularly in areas where there is no sufficient number of gauges or poor gauge distribution but they should be evaluated in different areas using ground-based data as references. In the present study, daily Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement (GPM- IMERG- Final (Version 5)) and Global Satellite Mapping of Precipitation-Moving Vector with Kalman filter (GSMaP-MVK (Version 7)) precipitation products were evaluated in comparison with gauges observations in Ardabil province, north-west of Iran, from 1 January 2016 to 21 October 2017. Several statistical indices including linear correlation coefficient, Bias (B), Multiplicative Bias (B_m), Relative Bias (B_r), Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Probability of Detection (POD), False Alarm Ratio (FAR) and Critical Success Index (CSI) were used for evaluation. The results showed that the correlation between GSMaP estimates and gauge observations is higher than that of IMERG (0.42 and 0.33, respectively). On the other hand, GSMaP tends to overestimate precipitation substantially, while IMERG is involved in both under and overestimation slightly. Although these products could not show very high accuracy in precipitation estimation, the estimated precipitation values by IMERG were relatively closer to gauge records and can be used as a replacement for gauge observation in the study area where there is lack of weather stations.     

Performance analysis of wound-field synchronous alternators underload using finite elements

A method is described for evaluating the performance of wound-field synchronous alternators under load using finite elements. The space-time phasor relationships of quantities in the synchronous machines are used to coordinate the set of instantaneous phase currents in the armature and field current in the rotor, with the geometry and load condition. The method uses the fact that the sensitivity matrix of the power/voltage with respect to the armature/rotor currents is diagonally dominant. The weak coupling of the power/voltage attributes to the relevant current sources permits a disintegration of the computational loop into a weakly coupled dual loop, in which one loop tries to match the terminal power factor by systematically adjusting the armature currents while the other tries to match the terminal voltage by modifying the field current. The method is illustrated by examples of its application, and the results are given     

A flexible dynamic traffic model for reverse link CDMA cellular networks

In this paper, we focus on the reverse link traffic analysis of a code-division multiple-access (CDMA) cellular network in dynamic environments. In this respect, we propose a new and flexible traffic model, which takes into account the interference-limitedness attribute of CDMA capacity as well as its soft-handoff feature. This new traffic model is developed according to an interference-based call admission control (ICAC) method and a geographical structure with three regions. The main advantage of this traffic model is in its flexibility when we consider different traffic conditions including time-varying status of traffic in the neighboring cells.     

Sound attenuation of interpenetrating polymer network foams

Interpenetrating polymer networks (IPNs) composed of polyurethanes and epoxies were prepared by the simultaneous technique. Modifications of the polymer structures resulted in a series of IPNs exhibiting semimiscible behavior, as evidenced by broad glass transitions in the dynamic mechanical spectra. Since this indicates materials with potentially good sound attenuation properties as a function of temperature and frequency, foams were prepared from these IPN systems. Enhanced sound absorption occurred in these foams when measured using the impedance tube method.     

Towards distributed emergency flow prioritization in software-defined networks

Emergency services must be able to transfer data with high priority over different networks. With 5G, slicing concepts at mobile network connections are introduced, allowing operators to divide portions of their network for specific use cases. In addition, Software-Defined Networking (SDN) principles allow to assign different Quality-of-Service (QoS) levels to different network slices. This paper proposes a microservices-based framework, able to run both centralized and distributed, that guarantees the required bandwidth for the emergency flows and maximizes the best-effort flows over the remaining bandwidth based on their priority. The proposed framework consists of an offline linear model, allowing to optimize the problem for a batch of flow requests. For dynamic situations, an online approach is also required in the framework to handle new incoming flows by calculating the path with a shortest path algorithm and utilizing a greedy approach in assigning bandwidth to the intermediate flows. In this article, the linear model is evaluated through simulation, the distributed architecture is evaluated through emulation while the online approach is validated through physical experiments with SDN switches. The results show that the linear model is able to guarantee the resource allocation for the emergency flows while optimizing the best-effort flows with a sub-second execution time. The distributed architecture is able to split up the managed network into different parts, allowing division of work between controllers. As a proof-of-concept, a prototype with Zodiac switches validates the feasibility of the centralized framework.     

Thermal actuation and confinement of water droplets on paper-based digital microfluidics devices

In this paper, the thermocapillary actuation is implemented to manipulate and confine the fluid droplets in a paper-based digital microfluidics (PB-DMF) device. The main advantage of using the thermocapillary actuation over the traditional electrowetting-on-dielectric actuation in the DMF devices is its ability to work with lower operating DC voltages. The proposed device is fabricated by the low-cost screen printing method using very low-cost materials. In order to overcome the weak controllability of the device over the droplets, a new thermal confinement technique is proposed which simply embedded in the device electrode pattern. A new thermally actuated valve is also designed to work based on thermocapillary actuation for switching on or off the droplets. The fabricated DMF device and the thermal valve are both combined with a microfluidics paper-based analytical device to form a hybrid paper chip in which the droplets are driven by both channel-based and droplet-based devices. The device operation is tested by using a biochemical glucose colorimetric detection assay.     

Pre-bent shape design of full free-form curved beams using isogeometric method and semi-analytical sensitivity analysis

In this paper, isogeometric analysis (IGA) is employed to solve the problem of a curved beam with free-form geometry, arbitrary loading, and variable flexural/axial rigidity. The main objective of the study is to develop a unified approach for full free-from curved beam problems that can be integrated with a newly developed semi-analytical sensitivity analysis to solve pre-bent shape design problems. The required set of B-spline control points are calculated using an interpolation technique based on chord-length parameterization. The one-to-one correspondence is considered for parameters of the geometry, loading, and rigidity which is proven to have extreme importance. An IGA curved beam element is suggested based on the Euler-Bernoulli beam theory for the general curvilinear coordinate. The validity and effectiveness of the proposed formulation is confirmed by application to a variety of examples. Moreover, three shape optimization examples are taken into consideration. In the first two examples, the pre-bent shapes of spiral and Tschinhausen curved beams with free-form geometry under distributed loading are obtained. In the third example, the pre-bending problem of wind turbine blades is addressed as an industrial example.     

A framework for designing cognitive trajectory controllers using genetically evolved interval type-2 fuzzy cognitive maps

In this paper, we provide a complete framework for the design of genetically evolved cognitive tracking controller based on interval type-2 (IT2) fuzzy cognitive map (FCM). We construct the cognitive controller based on a nonlinear controller by transforming its representation into a FCM. This representation gives the opportunity to prove the stability of the cognitive controller in the framework of nonlinear control theory. Moreover, with the deployment of IT2-fuzzy sets which are known to be capable to handle high level of uncertainty, the proposed cognitive controller has the ability to deal with uncertainty that are encountered in real-time world applications. To accomplish the design of the cognitive controller, we present a systematic approach based on genetic algorithm to optimize its parameters and learn fuzzy rules by extracting them from model space (e.g., a set of rules). Within the paper, all steps in constructing and designing the IT2-FCM-based cognitive controller are presented. We first show the performance improvements of the proposed IT2-FCM-based tracking controller with extensive and comparative simulation results and then with experimental results that were collected on real-world mobile robot. The results clearly show the superiority of proposed cognitive control systems when compared to its conventional and fuzzy controller counterparts. We believe that the proposed genetically evolved design approach of the IT2-FCM-based cognitive controller will provide a bridge between the well-developed cognitive sciences and control theory.