A Hierarchical Routing Graph for Supporting Mobile Devices in Industrial Wireless Sensor Networks

As many industrial applications require real-time and reliability communication, a variety of routing graph construction schemes were proposed to satisfy the requirements in Industrial Wireless Sensor Networks (IWSNs). Each device transmits packet through a route which is designated based on the graph. However, as existing studies consider a network consists of static devices only, they cannot cope with the network changes by movement of mobile devices considered important in the recent industrial environment. Thus, the communication requirements cannot be guaranteed because the existing path is broken by the varying network topology. The communication failure could cause critical problems such as malfunctioning equipment. The problem is caused repeatedly by continuous movement of mobile devices, even if a new graph is reconstructed for responding the changed topology. To support mobile devices exploited in various industrial environments, we propose a Hierarchical Routing Graph Construction (HRGC). The HRGC is consisted of two phases for hierarchical graph construction: In first phase, a robust graph called skeleton graph consisting only of static devices is constructed. The skeleton graph is not affected by network topology changes and does not suffer from packet loss. In second phase, the mobile devices are grafted into the skeleton graph for seamless communication. Through the grafting process, the routes are established in advance for mobile device to communicate with nearby static devices in anywhere. The simulation results show that the packet delivery ratio is improved when the graph is constructed through the HRGC

Design and Evaluation of Schemes for Replacing Multiple Member Vehicles in Vehicular Clouds

Vehicular clouds are considered an attractive approach to provide various services such as safety and entertainment applications by sharing resources between vehicles. Due to the free mobility of vehicles, vehicular clouds need to reconstruct by replacing leaving member vehicles with new member vehicles. When multiple member vehicles leave a vehicular cloud at different times, the design of an efficient member vehicle replacement scheme is a very challenging issue on determining the replacement timing. However, the research on the replacement of multiple member vehicles has little interest and is still in its infancy. Therefore, we propose three schemes to replace multiple member vehicles in vehicular clouds at three different replacement timings: MIN, MAX, and AVG. The MIN scheme replaces all of leaving member vehicles at the leaving time of the first leaving member vehicle, while the MAX scheme replaces all of leaving member vehicles at the leaving time of the last leaving member. The AVG scheme replaces all leaving member vehicles at the average time of their leaving times as a compromise between the Min and Max schemes. First, we determine the first leaving time, the last leaving time, and the average leaving time for each scheme by calculating the distance between a cloud requester vehicle and its member vehicles. Next, we choose replacement member vehicles to minimize the wasted resource at the replacement timing in each scheme. Last, we provide the process for releasing the resource of the leaving member vehicles and allocating the resource of the replacement member vehicles in each scheme. Through simulation results conducted in various environments, we compare and evaluate the performance of our three schemes in terms of the success ratio of the cloud maintenance and the amount of the wasted resources

Design and Evaluation of Schemes for Replacing Multiple Member Vehicles in Vehicular Clouds

Vehicular clouds are considered an attractive approach to provide various services such as safety and entertainment applications by sharing resources between vehicles. Due to the free mobility of vehicles, vehicular clouds need to reconstruct by replacing leaving member vehicles with new member vehicles. When multiple member vehicles leave a vehicular cloud at different times, the design of an efficient member vehicle replacement scheme is a very challenging issue on determining the replacement timing. However, the research on the replacement of multiple member vehicles has little interest and is still in its infancy. Therefore, we propose three schemes to replace multiple member vehicles in vehicular clouds at three different replacement timings: MIN, MAX, and AVG. The MIN scheme replaces all of leaving member vehicles at the leaving time of the first leaving member vehicle, while the MAX scheme replaces all of leaving member vehicles at the leaving time of the last leaving member. The AVG scheme replaces all leaving member vehicles at the average time of their leaving times as a compromise between the Min and Max schemes. First, we determine the first leaving time, the last leaving time, and the average leaving time for each scheme by calculating the distance between a cloud requester vehicle and its member vehicles. Next, we choose replacement member vehicles to minimize the wasted resource at the replacement timing in each scheme. Last, we provide the process for releasing the resource of the leaving member vehicles and allocating the resource of the replacement member vehicles in each scheme. Through simulation results conducted in various environments, we compare and evaluate the performance of our three schemes in terms of the success ratio of the cloud maintenance and the amount of the wasted resources

Optimum Modeling of 3-D Circular Braided Composites.

An effective geometric modeling is developed in order so that precise material properties of the 3-D circular-braided composite can be estimated. Most researchers of this field use straight lines to describe their yarn paths in the braided composite unit cell. However, in this study, yarn paths are described as curved lines using third-order spline, which are close to real geometric formation of the 3-D braided composite. Unit cells should be classified into several different categories because of a specificity of the 3-D braided composite. Particularly, in terms of 3-D circular-braided composites, a couple of unit cells can be taken

Agent-Based Multipath Management for Supporting Sink Mobility in Wireless Sensor Networks

In wireless sensor networks, sink mobility support is one of the essential functionalities in many applications. With continuous advancement, future applications will require not only sink mobility support but also high-performance data delivery service. Multipath routing is one of the promising technologies for improving data delivery performance by collaboratively using alternative or redundant multiple routing paths. However, existing multipath routing protocols had not dealt with sink mobility. As a result, they lead to bad performance in terms of energy efficiency due to the end-to-end path reconstruction. Consequently, a novel multipath management scheme is required thereby supporting sink mobility without performance degradation. In this paper, we propose a multipath management scheme for supporting sink mobility. The proposed scheme dynamically constructs multipath along the moving path of a sink. In addition, the proposed scheme provides the path shortening schemes according to the sink’s movement for reducing energy consumption. Our simulation results show that the proposed scheme is superior to existing path management schemes in terms of reliability and energy efficiency

Constitutive Equations Based on Cell Modeling Method for 3D Circular Braided Glass Fiber Reinforced Composites

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained for two volume fractions

Time-lapse electrical resistivity tomography and ground penetrating radar mapping of the active layer of permafrost across a snow fence in Cambridge Bay, Nunavut Territory, Canada: correlation interpretation using vegetation and meteorological data

International audienc

Selectivity of neuromodulatory projections from the basal forebrain and locus ceruleus to primary sensory cortices

Acetylcholine and noradrenaline are major neuromodulators that affect sensory processing in the cortex. Modality-specific sensory information is processed in defined areas of the cortex, but it is unclear whether cholinergic neurons in the basal forebrain (BF) and noradrenergic neurons in the locus ceruleus (LC) project to and modulate these areas in a sensory modality-selective manner. Here, we mapped BF and LC projections to different sensory cortices of the mouse using dual retrograde tracing. We found that while the innervation of cholinergic neurons into sensory cortices is predominantly modality specific, the projections of noradrenergic neurons diverge onto multiple sensory cortices. Consistent with this anatomy, optogenetic activation of cholinergic neurons in BF subnuclei induces modality-selective desynchronization in specific sensory cortices, whereas activation of noradrenergic LC neurons induces broad desynchronization throughout multiple sensory cortices. Thus, wedemonstrate a clear distinction in the organization and function of cholinergic BF and noradrenergic LC projections into primary sensory cortices: cholinergic BF neurons are highly selective in their projections and modulation of specific sensory cortices, whereas noradrenergic LC neurons broadly innervate and modulate multiple sensory cortices.N

Selectivity of Neuromodulatory Projections from the Basal Forebrain and Locus Ceruleus to Primary Sensory Cortices

Acetylcholine and noradrenaline are major neuromodulators that affect sensory processing in the cortex. Modality-specific sensory information is processed in defined areas of the cortex, but it is unclear whether cholinergic neurons in the basal forebrain (BF) and noradrenergic neurons in the locus ceruleus (LC) project to and modulate these areas in a sensory modality-selective manner. Here, we mapped BF and LC projections to different sensory cortices of the mouse using dual retrograde tracing. We found that while the innervation of cholinergic neurons into sensory cortices is predominantly modality specific, the projections of noradrenergic neurons diverge onto multiple sensory cortices. Consistent with this anatomy, optogenetic activation of cholinergic neurons in BF subnuclei induces modality-selective desynchronization in specific sensory cortices, whereas activation of noradrenergic LC neurons induces broad desynchronization throughout multiple sensory cortices. Thus, wedemonstrate a clear distinction in the organization and function of cholinergic BF and noradrenergic LC projections into primary sensory cortices: cholinergic BF neurons are highly selective in their projections and modulation of specific sensory cortices, whereas noradrenergic LC neurons broadly innervate and modulate multiple sensory cortices.N

Somatostatin enhances visual processing and perception by suppressing excitatory inputs to parvalbumin-positive interneurons in V1

© 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).Somatostatin (SST) is a neuropeptide expressed in a major subtype of GABAergic interneurons in the cortex. Despite abundant expression of SST and its receptors, their modulatory function in cortical processing remains unclear. Here, we found that SST application in the primary visual cortex (V1) improves visual discrimination in freely moving mice and enhances orientation selectivity of V1 neurons. We also found that SST reduced excitatory synaptic transmission to parvalbumin-positive (PV+) fast-spiking interneurons but not to regular-spiking neurons. Last, using serial block-face scanning electron microscopy (SBEM), we found that axons of SST+ neurons in V1 often contact other axons that exhibit excitatory synapses onto the soma and proximal dendrites of the PV+ neuron. Collectively, our results demonstrate that the neuropeptide SST improves visual perception by enhancing visual gain of V1 neurons via a reduction in excitatory synaptic transmission to PV+ inhibitory neurons11Nsciescopu