Regular Mesh Topology Research Articles

Distributed aerial processing for IoT-based edge UAV swarms in smart farming

This work addresses the challenges of a decentralized and heterogeneous Unmanned Aerial Vehicle (UAV) swarm deployment – some fitted with multimedia sensors, while others armed with scalar sensors – in resource-constrained and challenging environments, typically associated with farming. Subsequently, we also address the resulting problem of sensing and processing resource-intensive data aerially within the Edge swarm in the fastest and most efficient manner possible. The heterogeneous nature of the Edge swarm results in under-utilization of the available computation resources due to unequal data generation within its members. To address this, we propose a Nash bargaining-based weighted intra-Edge processing offload scheme to mitigate the problem of heavy processing in some of the swarm members. We do this by distributing the data to be processed to all the swarm members. Real-life hardware tuned simulation of a large UAV swarm shows that by increasing the number of UAVs in the swarm, our scheme achieves better scalability and reduced processing delays for intensive processing tasks. Additionally, in comparison to regular star and mesh topologies, our scheme achieves an increase in collective available network processing speeds by 100% for only 25% of the number of UAVs in a star topology.

All-Pairs Shortest Paths Algorithm for Regular 2D Mesh Topologies

All-Pairs Shortest Paths Algorithm for Regular 2D Mesh Topologies

Application-Specific Network-on-Chip synthesis with flexible router Placement

Network-on-Chip (NoC) has been proposed as a possible solution to the communication problem in nanoscale System-on-Chip (SoC) design. NoC architectures with optimized application-specific topologies have been found to be superior to the regular architectures in designing Multi-Processor System-on-Chip (MPSoC) solutions. The application specific NoC design problem takes as input the chip floorplan, library of NoC components, and communication requirements between the tasks of the application. It outputs the positions of the routers in the floorplan, such that, all communication requirements of the application are satisfied. This paper presents an Integer Linear Programming formulation of the problem, followed by a heuristic technique based on Particle Swarm Optimization (PSO) for finding the router positions from the set of available positions within the chip floorplan. The goal is to minimize the communication cost between cores, satisfying both the link length and router port constraints. The results have been shown on realistic benchmarks. Comparisons have been carried out with regular mesh and custom architectures having routers positioned at (i) the corners of the cores, (ii) the centers of the cores, and (iii) the intersections of the cores. Significant reductions in communication cost have been observed over all the cases. For smaller benchmarks, the optimum results obtained via ILP matches exactly with those reported by the PSO. Many of the existing router placement policies fail even for these small benchmarks, when restrictions are imposed on permissible link length. This establishes the merit of the PSO formulation. Link and router energy consumption of the synthesized NoC have been compared with regular mesh based architectures. The results show significant reduction in communication cost, area overhead, link energy and router energy in the synthesized NoC over regular mesh topology as well.

High-level customization framework for application-specific NoC architectures

Network-on-Chip (NoC) has been recognized as the new paradigm to interconnect and organize a high number of cores. NoCs address global communication issues in System-on-Chips (SoC) involving communication-centric design and implementation of scalable communication structures evolving application-specific NoC design as a key challenge to modern SoC design. In this paper we present a SystemC customization framework and methodology for automatic design and evaluation of regular and irregular NoC architectures. The presented framework also supports application-specific optimization techniques such as priority assignment, node clustering and buffer sizing. Experimental results show that generated regular NoC architectures achieve an average of 5.5 % lower communication-cost compared to other regular NoC designs while irregular NoCs proved to achieve on average 4.5×higher throughput and 40 % network delay reduction compared to regular mesh topologies. In addition, employing a buffer sizing algorithm we achieve a reduction in network's power consumption by an average of 45 % for both regular and irregular NoC design flow.

Systematic selection of cluster heads for data collection

We present a systematic approach to selecting cluster heads (CHs) in networked sensing systems for data aggregation based on the idea of dominating sets of a graph. A set of vertices, D of a graph G=(V,E) is a k-dominating set if every vertex v∈V, is connected to some vertex in D via path of length less than or equal to k. By focusing on regular mesh topologies, in which each node has q neighbors, q=3,4,6,8, we demonstrate an intuitive approach for identifying the CHs. If E is the energy required for a node to send a message to a collection point, e is the energy required to send a similar message to its adjacent node in the system, and C is the compression ratio achieved by aggregation techniques at a CH, we show that CHs selected in our approach are viable whenever k<(3.C.E/2e)−1/2. We present simulation results that validate the analysis and demonstrate how k affects the Quality of Service of the data aggregation scheme. Finally, we show that the approach extends to systems that have non-regular topologies.

Mesh topology in scanned garment reconstruction

PurposeThe purpose of this paper is to investigate the draping behavior of a scanned garment model in irregular and regular mesh topology. 3D garment with high fidelity can be obtained via range data scanning. The original output of a body scanner is an unorganized points cloud. In this paper, the geometrical surface of 3D garment is reconstructed through a series of treatments.Design/methodology/approachThe primary target of this work is to investigate the dynamic behavior of the corresponding physical model transferred from different mesh topologies. A mass‐spring model is constructed for both regular and irregular meshes. The performance under various integration methods is evaluated.FindingsExperimental results reveal the procedure of regularization is suitable for the integrators that are sensitive to the physically‐based simulation of scanned garments.Originality/valueThe geometrical surface of 3D garment is reconstructed through a series of treatments solving the problem of points cloud data for high definition 3D data.

IMPROVED MODIFIED FAT-TREE TOPOLOGY NETWORK-ON-CHIP

C-based cycle-accurate simulations are used to evaluate the performance of a Network-on-Chip (NoC) based on an improved version of the modified Fat Tree topology. The modification simplifies routing further and guarantee orderly reception of packets without any loss of performance. Several traffic models have been used in these simulations; Bursty and non-bursty traffic with uniformly-distributed destination addresses and non-uniformly-distributed destination addresses. A simple new traffic model has been developed for generating non-uniformly-distributed destination addresses. This model is general enough to be used in developing new NoC architectures and captures universally accepted place-and-route methodologies. Simulation results are used to illustrate how the hardware resources of a modified Fat Tree NoC can be minimized without affecting the network performance. The performance of a NoC with regular Mesh topology was also evaluated for comparison with the modified Fat Tree topology.

An Algorithm to Generate Regular Mesh Topology for Wireless Networks

The wireless mesh networks (WMNs) is aiming to provide last mile broadband access to internet. It is important to improve the WMN overlay area by generating a regular mesh or expending a small scale WMN to a larger one. This paper proposes methods to reproduce a constant degree mesh. The graph model is useful in WMNs deployment and scale expansion. Considering nature environment and surrounding buildings, extending the current mesh can choose different style to meet the surrounding requirements. Some useful conclusions on the shortest path number and hop counting are raised to promise simultaneous paths. Furthermore, the feasible expanding method is shown by forming larger WMN via bounder nodes growing into new units in a given mesh.

On an efficient NoC multicasting scheme in support of multiple applications running on irregular sub-networks

When a number of applications simultaneously running on a many-core chip multiprocessor (CMP) chip connected through network-on-chip (NoC), significant amount of on-chip traffic is one-to-many (multicast) in nature. As a matter of fact, when multiple applications are mapped onto an NoC architecture with applicable traffic isolation constraints, the corresponding sub-networks of these applications are mapped onto actually tend to be irregular. In the literature, multicasting for irregular topologies is supported through either multiple unicasting or broadcasting, which, unfortunately, results in overly high power consumption and/or long network latency. To address this problem, a simple, yet efficient hardware-based multicasting scheme is proposed in this paper. First, an irregular oriented multicast strategy is proposed. Literally, following this strategy, an irregular oriented multicast routing algorithm can be designed based on any regular mesh based multicast routing algorithm. One such algorithm, namely, Alternative Recursive Partitioning Multicasting (AL + RPM), is proposed based on RPM, which was designed for regular mesh topology originally. The basic idea of AL + RPM is to find the output directions following the basic RPM algorithm and then decide to replicate the packets to the original output directions or the alternative (AL) output directions based on the shape of the sub-network. The experiment results show that the proposed multicast AL + RPM algorithm can consume, on average, 14% and 20% less power than bLBDR (a broadcasting-based routing algorithm) and the multiple unicast scheme, respectively. In addition, AL + RPM has much lower network latency than the above two approaches. To incorporate AL + RPM into a baseline router to support multicasting, the area overhead is fairly modest, less than 5.5%.

Scalability of relaxed consistency models in NoC based multicore architectures

This paper studies realization of relaxed memory consistency models in the network-on-chip based distributed shared memory (DSM) multi-core systems. Within DSM systems, memory consistency is a critical issue since it affects not only the performance but also the correctness of programs. We investigate the scalability of the relaxed consistency models (weak, release consistency) implemented by using transaction counters. Our experimental results compare the average and maximum code, synchronization and data latencies of the two consistency models for various network sizes with regular mesh topologies. The observed latencies rise for both the consistency models as the network size grows. However, the scaling behaviors are different. With the release consistency model these latencies grow significantly slower than with the weak consistency due to better optimization potential by means of overlapping, reordering and program order relaxations. The release consistency improves the performance by 15.6% and 26.5% on average in the code and consistency latencies over the weak consistency model for the specific application, as the system grows from single core to 64 cores. The latency of data transactions grows 2.2 times faster on the average with a weak consistency model than with a release consistency model when the system scales from single core to 64 core

Multipath Dissemination in Regular Mesh Topologies

Mesh topologies are important for large-scale peer-to-peer systems that use low-power transceivers. The quality of service (QoS) in such systems is known to decrease as the scale increases. We present a scalable approach for dissemination that exploits all the shortest paths between a pair of nodes and improves the QoS. Despite the presence of multiple shortest paths in a system, we show that these paths cannot be exploited by spreading the messages over the paths in a simple round-robin manner; nodes along one of these paths will always handle more messages than the nodes along the other paths. We characterize the set of shortest paths between a pair of nodes in regular mesh topologies and derive rules, using this characterization, to effectively spread the messages over all the available paths. These rules ensure that all the nodes that are at the same distance from the source handle roughly the same number of messages. By modeling the multihop propagation in the mesh topology as a multistage queuing network, we present simulation results from a variety of scenarios that include link failures and propagation irregularities to reflect real-world characteristics. Our method achieves improved QoS in all these scenarios.

Wireless mesh networks channel reservation: modelling and delay analysis

In order to overcome the negotiation procedure bottleneck of the standard DCF in wireless mesh networks, the authors propose a new channel reservation function (CRF) that reduces the negotiation overhead of the DCF, which as a result reduces the overall transmission delay effectively without of any extra bandwidth consumption. Furthermore, the authors provide an analytical model for the proposed scheme for which the simulation results measure the amount that the new method can reduce the average total delay for both regular and fragmented mesh topologies demonstrating superiority of the new method over the classic 802.11 solution. Additionally, the authors extend the scheme to multichannel CRF upon which the proposed method can be used for multichannel applications.

On the Accuracy of First-Order Numerical Derivatives in Multidimensional Digital Waveguide Mesh Topologies

Digital waveguide mesh (DWM) models are numerical solvers for the wave equation in -dimensions. They are used for obtaining the traveling-wave solution in practical acoustical modeling applications. Although unstructured meshes can be used with DWMs, regular mesh topologies are traditionally used due to their implementation simplicity. This letter discusses the accuracy of first-order approximations to numerical derivatives on more general unstructured mesh topologies. The results are applied to structured, regular mesh topologies as used in DWM modeling. A comparison of 2-D and 3-D DWM topologies with respect to the accuracy of first-order approximations to numerical derivatives is presented.

Deadlock free routing algorithms for irregular mesh topology NoC systems with rectangular regions

The simplicity of regular mesh topology Network on Chip (NoC) architecture leads to reductions in design time and manufacturing cost. A weakness of the regular shaped architecture is its inability to efficiently support cores of different sizes. A proposed way in literature to deal with this is to utilize the region concept, which helps to accommodate cores larger than the tile size in mesh topology NoC architectures. Region concept offers many new opportunities for NoC design, as well as provides new design issues and challenges. One of the most important among these is the design of an efficient deadlock free routing algorithm. Available adaptive routing algorithms developed for regular mesh topology cannot ensure freedom from deadlocks. In this paper, we list and discuss many new design issues which need to be handled for designing NoC systems incorporating cores larger than the tile size. We also present and compare two deadlock free routing algorithms for mesh topology NoC with regions. The idea of the first algorithm is borrowed from the area of fault tolerant networks, where a network topology is rendered irregular due to faults in routers or links, and is adapted for the new context. We compare this with an algorithm designed using a methodology for design of application specific routing algorithms for communication networks. The application specific routing algorithm tries to maximize adaptivity by using static and dynamic communication requirements of the application. Our study shows that the application specific routing algorithm not only provides much higher adaptivity, but also superior performance as compared to the other algorithm in all traffic cases. But this higher performance for the second algorithm comes at a higher area cost for implementing network routers.

Generating subdivision surfaces from profile curves

The construction of freeform models has always been a challenging task. A popular approach is to edit a primitive object such that its projections conform to a set of given planar curves. This process is tedious and relies very much on the skill and experience of the designer in editing 3D shapes. This paper describes an intuitive approach for the modeling of freeform objects based on planar profile curves. A freeform surface defined by a set of orthogonal planar curves is created by blending a corresponding set of sweep surfaces. Each of the sweep surfaces is obtained by sweeping a planar curve about a computed axis. A Catmull–Clark subdivision surface interpolating a set of data points on the object surface is then constructed. Since the curve points lying on the computed axis of the sweep will become extraordinary vertices of the subdivision surface, a mesh refinement process is applied to adjust the mesh topology of the surface around the axis points. In order to maintain characteristic features of the surface defined with the planar curves, sharp features on the surface are located and are retained in the mesh refinement process. This provides an intuitive approach for constructing freeform objects with regular mesh topology using planar profile curves.

Adaptive routing for packet-oriented intersatellite link networks: performance in various traffic scenarios

Regular mesh topologies typical for satellite communication networks comprised of intersatellite links provide high network flexibility and reliability, but due to dynamic changing of traffic load and interorbit link distance variation, adaptive routing is an absolute requirement for optimizing the network utilization. In this article, we address adaptive routing in the intersatellite link (ISL) segment of nongeostationary packet-switched satellite communication systems, focusing on the relative impacts of traffic load and propagation delay on the link cost. We consider four reference traffic flow scenarios with different levels of traffic concentration. he network performance is evaluated in terms of routing performance measures important from both the end user and the network operator perspectives. Using an ISL network simulator, we reveal some intrinsic effects of the selected constellation and effects introduced with different assumptions regarding the traffic model.

Incremental design of scalable interconnection networks using basic building blocks

In this paper, we present an incremental design of scalable interconnection networks in multicomputer systems using basic building blocks. Both network topologies and routing algorithms are considered. We use wormhole-routed small-scale 2D meshes as basic building blocks. The minimum requirement to expand these networks is a single building block. This implies that the network does not have to maintain the regular 2D mesh topology. Some new topologies are introduced: incomplete meshes based on those adaptive routing algorithms designed from the turn model and extended incomplete meshes based on XY routing. We show that the original routing algorithm can be adopted to send a message between any source and destination without using store-and-forward and causing deadlock. The way that the network is constructed incrementally requires no or a very small amount of rewiring and keeps high bisection density and short diameter of the network. The design methods can be used to economically and incrementally build expandable and scalable parallel computers.

An adaptive curvilinear-coordinate approach to dynamic load balancing of parallel multiresolution molecular dynamics

We present a practical experience in adding a dynamic-load-balancing capability to an existing large parallel application — multiresolution molecular dynamics (MRMD) — which is based on uniform mesh decomposition. The new load-balancing scheme uses adaptive curvilinear coordinates to represent partition boundaries. Workloads are partitioned with a uniform 3-dimensional mesh in the curvilinear coordinate system. Simulated annealing is used to determine the optimal coordinate system which minimizes load imbalance and communication costs. The number of messages for performing simulations is minimal because of the underlying regular mesh topology. Periodic boundary conditions are naturally incorporated in the new scheme. Performance of the MRMD algorithm with the new load balancer has been tested for nonuniform multimillion-atom systems.

‘Dead reckoning’ — a primitive and efficient self-routing protocol for ultrafast mesh networks

The authors describe a new approach to the problem of self-routing in ultra-high-speed multi-computer interconnection networks. The method is based on the concept of ‘dead reckoning’ (self-navigation without the use of landmarks), and is applicable to networks with a mainly regular mesh topology. The packet header contains, in addition to the usual destination address, a tiny amount of directional information (as little as 2 bits in the case of the Manhattan street network). With this additional data, the algorithm for path selection at the network nodes becomes extraordinarily simple, allowing very fast processing with good routing efficiency and high throughput. Most significantly, with this method it is not necessary to read each binary digit of the destination address of every packet arriving at every intermediate routing node; it is sufficient only to perform a single-stage pattern match between the packet address and the address of the routing node. This feature, and the low latency of this self-routing technique, make it particularly well suited to ultrafast photonic networks.

Two simple techniques for broadcasting in deflection routing multichannel MANs

Multiconnected and regular mesh topologies address the accomplishment of high throughput and availability as required by prospective high-speed communication networks. Bidirectional Manhattan Street Network (BMSN) and Shuffle Net (SN) are multiconnected topologies implementing the logical layout of so-called multichannel metropolitan area networks. Broadcasting is an open issue in multichannel MANs. This paper proposes two simple distributed techniques to deliver broadcast traffic in BMSN and SN. The two techniques are compared on the basis of throughput and delay results obtained by simulation. The robustness of the proposed broadcasting schemes with respect to failures, is also considered.