Scenario Assessment of Streamflow Simulation and its Transition Probability in Future Periods Under Climate Change

The effect of climate change on water resources is an important challenge. To analyze the negative effects of this phenomenon and recommend adaptive measures, it is necessary to assess streamflow simulation scenarios and streamflow transition probabilities in future periods. This paper employs the HadCM3 (Hadley Centre Coupled Model, version 3) model to generate climate change scenarios in future periods (2010–2039, 2040–2069, and 2070–2099) and under A2 emission scenarios. By introducing climatic variable time series in future periods to the IHACRES (Identification of unit Hydrographs And Component flows from Rainfall, Evaporation and Streamflow data) hydrological model, long-term streamflow simulation scenarios are produced. By fitting statistically different distributions on runoff produced by using goodness-of-fit tests, the most appropriate statistical distribution for each month is chosen and relevant statistical parameters are extracted and compared with statistical parameters of runoff in the base period. Results show that long-term annual runoff average in the three future periods compared to the period 2000–1971 will decrease 22, 11, and 65 %, respectively. ?Despite the reduction in total runoff volume in future periods compared to the baseline period, the decrease is related to medium and high flows. In low flows, total runoff volumes for future periods compared to the baseline period will increase 47, 41, and 14 %, respectively. To further assess the impact of annual average runoff on flows, it is necessary to examine the correlation of time series using streamflow transition probabilities. To compare the streamflow transition probability in each of the future periods with base period streamflow in each month, streamflow is discretized and performance criteria are used. Results show a low coefficient of correlation and high error indicators.     

Effects of Pipe Roughness Uncertainty on Water Distribution Network Performance During its Operational Period

The design of new water distribution networks (WDNs) is an important social problem. Failures during an operational period provoke deficits in consumption nodes thus decreasing the performance of the network. WDN performance can be defined as the ability to sufficiently secure demand and desirable pressure in nodes based on changes in design parameters. This paper focuses on the evaluation of network performance during an operational period, taking into account pipe roughness uncertainty. A network analysis is performed by generating probabilistic series of pipe roughness using Monte Carlo simulation (MCS) in the operational period of the Two-loop WDN. Results show that an increase in pipe roughness uncertainty causes a decrease in network performance in the operational period. Furthermore, the network has a desirable efficiency only in the first 10 years. Thus, the proposed design methodology that considers the uncertainty of design variables is an effective procedure to evaluate network performance.     

Energy-efficient,fast-settling,modified nested-current-mirror,single-stage-amplifier for high-resolution LCDs in 90-nm CMOS

The Internet of Things (IoT) presents opportunities to address a variety of systemic, metabolic healthcare issues. Cardiovascular disease and diabetes are among the greatest contributors to premature death worldwide. Wireless wearable continuous monitoring systems such as ECG sensors connected to the IoT can greatly decrease the risk of death related to cardiac issues by providing valuable long-term information to physicians, as well as immediate contact with emergency services in the event of a heart attack or stroke. In this report we discuss the fabrication, characterization and validation of composite fabric ECG sensors made from Nylon^® coated with reduced graphene oxide (rGO_x) as part of a self-powered wearable IoT sensor. We utilize an electronic probing station to measure electrical properties, take live ECG data to measure signal reliability, and provide detailed surface characterization through scanning electron microscopy. Finally, bonding between the layers of the composite and between composite and the Nylon^® is analyzed by Fourier transform Infrared spectroscopy. Furthermore, a low power analog front end circuit designed in 65 nm CMOS process is presented to interface the sensor with a system on chip used in a wearable IoT healthcare device.     

A Model-Based Reinforcement Learning Protocol for Routing in Vehicular Ad hoc Network

Todays by equipping vehicles with wireless technologies, Vehicular Ad Hoc Network (VANET) has been emerged. This type of network can be utilized in many fields such as emergency, safety or entertainment. It is also considered as a main component of intelligent transportation system. However, due to the nodes velocity (vehicles velocity), varying density, obstacles and lack of fixed infrastructure, finding and maintaining a route between nodes are always challenging in VANET. Any routing protocol can be effective only if the nodes can learn and adapt themselves with such a dynamic environment. One way to achieve this adaptation is using machine learning techniques. In this paper we try to reach this goal by applying Multi-Agent Reinforcement Learning (MARL) that enables agents to solve routing optimization problems in a distributed way. Although model-free Reinforcement Learning (RL) schemes are introduced for this purpose, such techniques learn using a trial and error scheme in a real environment so they cannot reach an optimal policy in a short time. To deal with such a problem, we have proposed a mode-based RL based routing scheme. We have also developed a Fuzzy Logic (FL) system to evaluate the quality of links between neighbor nodes based on parameters such as velocity and connection quality. Outputs of this fuzzy system have been used to form the state transition model, needed in MARL. Results of evaluations have shown that our approach can improve some routing metrics like delivery ratio, end-to-end delay and traffic overhead.

     

Multi-objective algorithms for the application mapping problem in heterogeneous multiprocessor embedded system design

The Journal of Supercomputing - Design at the Electronic System-Level tackles the increasing complexity of embedded systems by raising the level of abstraction in system specification and modeling....     

Flow separation control in open-channel bends

The investigation of fluid flow in sharp open-channel bends is key to controlling undesired sedimentation in natural river reaches. The difficulties are associated with controlling the flow separation in meanderings. Flow separation decreases the width of the flow, and consequently, the conveyance capacity while increasing erosion and mixing. This study proposes a novel approach to reduce the flow separation at the inner banks of sharp open-channel bends. Three-dimensional numerical experiments were conducted. To find the most reliable procedure, five turbulence models were examined. The employed numerical approach is formulated within the framework of the finite volume method and the volume of fluid (VOF) technique to solve the Navier–Stokes equations. Water levels and velocity profiles are obtained in different sections of the channel and are compared to experimental studies of a 90° sharp open-channel bend. A close agreement is observed using the RSM (Reynolds stress model) turbulence model. Moreover, the evaluation of acquired velocity profiles demonstrates that in a regular bend, the lowest velocity occurs near the inner bank, where it has a flow separation tendency. The same numerical procedure is employed to simulate water flow through a sharp converging open-channel bend. The measurements of velocity profiles and velocity vectors in the curved sections support the idea that decreasing the channel width considerably reduces the overall velocity variations in cross-sectional areas of the test case and is effective to control flow separation.     

Design and fabrication of a new high gain multilayer negative refractive index metamaterial antenna for X‐band applications

This article presents the design of a planar high gain and wideband antenna using a negative refractive index multilayer superstrate in the X‐band. This meta‐antenna is composed of a four‐layer superstrate placed on a conventional patch antenna. The structure resonates at a frequency of 9.4 GHz. Each layer of the metamaterial superstrate consists of a 7 × 7 array of electric‐field‐coupled resonators, with a negative refractive index of 8.66 to 11.83 GHz. The number of layers and the separation of superstrate layers are simulated and optimized. This metamaterial lens has significantly increased the gain of the patch antenna to 17.1 dBi. Measurements and simulation results proved about 10 dB improvement of the gain.     

Cellulose nanocrystal (CNC)-based nanocomposites for UV curable high-solid coating systems

Demand for durable clear wood coatings is on the rise. Cellulose nanocrystals (CNC) constitute an organic nanomaterial widely studied in polymer composites for its reinforcing effect. In this study, CNC was used to enhance the performance of a UV curable high-solid content coating system intended for indoor environments. The CNC surface was modified by a cationic surfactant since the coating system was hydrophobic resin-based requiring hydrophobic nanomaterial reinforcement. Modified CNC was mixed with the coating system using a high-speed mixer and the ultrasonication technique. Mechanical, thermal and morphological properties and curing behavior of the newly developed UV-curing coatings were assessed. Inclusion of CNC in the coating increased the mechanical properties (hardness and reduced modulus) of the coating system to a large extent. Thermal stability of the coating system was also improved by CNC addition. The CNC did not affect the curing behavior of the coating, in contrast to most inorganic nanomaterials. The CNC dispersed well in the matrix at 1% loading. Results of this study show that CNC can be used successfully with high-solid content coating systems.