PDLB: Path Diversity-aware Load Balancing with Adaptive Granularity in Data Center Network

Modern data center topologies often take the form of a multi-rooted tree with rich parallel paths to provide high bandwidth. However, various path diversities caused by traffic dynamics, link failures and heterogeneous switching equipments widely exist in production data center network. Therefore, the multi-path load balancer in data center should be robust to these diversities. Although prior fine-grained schemes such as RPS and Presto make full use of available paths, they are prone to experi-ence packet reordering problem under asymmetric topology. The coarse-grained solutions such as ECMP and LetFlow effectively avoid packet reordering, but easily lead to under-utilization of multiple paths. To cope with these inefficiencies, we propose a load balancing mechanism called PDLB, which adaptively adjusts flowcell granularity according to path diversity. PDLB increases flowcell granularity to alleviate packet reordering under large degrees of topology asymmetry, while reducing flowcell granularity to obtain high link utilization under small degrees of topology asymmetry. PDLB is only deployed on the sender without any modification on switch. We evaluate PDLB through large-scale NS2 simulations. The experimental results show that PDLB reduces the average flow completion time by up to ∼11-53% over the state-of-the-art load balancing schemes.

Forest Optimization based Test Case Generation for Multiple Paths with Metamorphic Relations

In general multiple paths are covered by multiple runs which is a time consuming task. Now a days, metaheuristic techniques are widely used for path coverage. In order to reduce the time, an efficient method is proposed based on Forest Optimization Algorithm (FOA) with Metamorphic Relations (MRs) that cover multiple paths at a time in one run unlike the traditional search based testing. In the proposed approach, initial test case is generated using FOA, the successive test cases are generated using MRs without undergoing several runs. The motive of using FOA is that the searching mechanism of this algorithm having resemblance with the branch / path coverage techniques of testing. To the best of our knowledge, FOA has not been implemented in software testing. The experimental results are compared with three existing work. The efficiency of simply FOA is also shown how it able to cover multiple paths. The results show that FOA with MRs is more efficient in terms of time consumption and number of paths covered.

Lightweight Multi-Scale Asymmetric Attention Network for Image Super-Resolution

Recently, with the development of convolutional neural networks, single-image super-resolution (SISR) has achieved better performance. However, the practical application of image super-resolution is limited by a large number of parameters and calculations. In this work, we present a lightweight multi-scale asymmetric attention network (MAAN), which consists of a coarse-grained feature block (CFB), fine-grained feature blocks (FFBs), and a reconstruction block (RB). MAAN adopts multiple paths to facilitate information flow and accomplish a better balance of performance and parameters. Specifically, the FFB applies a multi-scale attention residual block (MARB) to capture richer features by exploiting the pixel-to-pixel correlation feature. The asymmetric multi-weights attention blocks (AMABs) in MARB are designed to obtain the attention maps for improving SISR efficiency and readiness. Extensive experimental results show that our method has comparable performance with fewer parameters than the current advanced lightweight SISR.

Language emergence can take multiple paths: Using motion capture to track axis use in Nicaraguan Sign Language

Research on emergent sign languages suggests that younger sign languages may make greater use of the z-axis, moving outwards from the body, than more established sign languages when describing the relationships between participants and events (Padden, Meir, Aronoff, and Sandler, 2010). This has been suggested to reflect a transition from iconicity rooted in the body (Meir, Padden, Aronoff, and Sandler, 2007) towards a more abstract schematic iconicity. We present the results of an experimental investigation into the use of axis by signers of Nicaraguan Sign Language (NSL). We analysed 1074 verb tokens elicited from NSL signers who entered the signing community at different points in time between 1974 and 2003. We used depth and motion tracking technology to quantify the position of signers’ wrists over time, allowing us to build an automated and continuous measure of axis use. We also consider axis use from two perspectives: a camera-centric perspective and a signer-centric perspective. In contrast to earlier work, we do not observe a trend towards increasing use of the x-axis. Instead we find that signers appear to have an overall preference for the z-axis. However, this preference is only observed from the camera-centric perspective. When measured relative to the body, signers appear to be making approximately equal use of both axes, suggesting the preference for the z-axis is largely driven by signers moving their bodies (and not just their hands) along the z-axis. We argue from this finding that language emergence patterns are not necessarily universal and that use of the x-axis may not be a prerequisite for the establishment of a spatial grammar.

Tracing the Milky Way’s Vestigial Nuclear Jet

MeerKAT radio continuum and XMM-Newton X-ray images have recently revealed a spectacular bipolar channel at the Galactic Center that spans several degrees (∼0.5 kpc). An intermittent jet likely formed this channel and is consistent with earlier evidence of a sustained, Seyfert-level outburst fueled by black hole accretion onto Sgr A* several Myr ago. Therefore, to trace a now weak jet that perhaps penetrated, deflected, and percolated along multiple paths through the interstellar medium, relevant interactions are identified and quantified in archival X-ray images, Hubble Space Telescope Paschen α images and Atacama Large Millimeter/submillimeter Array millimeter-wave spectra, and new SOAR telescope IR spectra. Hydrodynamical simulations are used to show how a nuclear jet can explain these structures and inflate the ROSAT/eROSITA X-ray and Fermi γ-ray bubbles that extend ± 75° from the Galactic plane. Thus, our Galactic outflow has features in common with energetic, jet-driven structures in the prototypical Seyfert galaxy NGC 1068.

Efficient and Safe Robotic Autonomous Environment Exploration Using Integrated Frontier Detection and Multiple Path Evaluation

Autonomous exploration and remote sensing using robots have gained increasing attention in recent years and aims to maximize information collection regarding the external world without human intervention. However, incomplete frontier detection, an inability to eliminate inefficient frontiers, and incomplete evaluation limit further improvements in autonomous exploration efficiency. This article provides a systematic solution for ground mobile robot exploration with high efficiency. Firstly, an integrated frontier detection and maintenance method is proposed, which incrementally discovers potential frontiers and achieves incremental maintenance of the safe and informative frontiers by updating the distance map locally. Secondly, we propose a novel multiple paths planning method to generate multiple paths from the robot position to the unexplored frontiers. Then, we use the proposed utility function to select the optimal path and improve its smoothness using an iterative optimization strategy. Ultimately, the model predictive control (MPC) method is applied to track the smooth path. Simulation experiments on typical environments demonstrate that compared with the benchmark methods, the proposed method reduce the path length by 27.07% and the exploration time by 27.09% on average. The real-world experimental results also reveal that our proposed method can achieve complete mapping with fewer repetitive paths.

Analysis of the Evolution of User Emotion and Opinion Leaders’ Information Dissemination Behavior in the Knowledge Q&A Community during COVID-19

Since its emergence in 2019, COVID-19 has quickly triggered widespread public discussion on social media. From 26 February 2020 to 26 September 2020, this study collected data on COVID-19-related posts in the knowledge Q&A community, identified 220 opinion leaders of this community, and used social network analysis and sentiment analysis to analyze the information exchange behavior and emotional evolution of the opinion leaders during COVID-19. The results show that the COVID-19 topic community could be divided into seven main categories. The information dissemination of opinion leader information dissemination network had low efficiency, multiple paths, and a high degree of control. In addition, the emotional evolution of users showed obvious phased characteristics. User emotion changed from initially strong negative to strong positive over the course of the pandemic and eventually tended to be objective and neutral as time passed and the event stabilized.

Reliability Aware Multiple Path Installation in Software-Defined Networking

Link failures frequently occur in communication networks, which negatively impacts network services delivery. Compared to traditional distributed networks, Software-Defined Networking (SDN) provides numerous benefits for link robustness to avoid services unavailability. To cope with link failures, the existing SDN approaches compute multiple paths and install corresponding flow rules at network switches without considering the reliability value of the primary computed path. This increases computation time, traffic overhead and end-to-end packets delay. This paper proposes a new approach called Reliability Aware Multiple Path Flow Rule (RAF) that calculates links reliability and installs minimum flow rules for multiple paths based on the reliability value of the primary path. RAF has been simulated, evaluated and compared with the existing approaches. The simulation results show that RAF performs better than the existing approaches in terms of computation overhead at the controller and reduces end-to-end packet delay and traffic overhead for flow rules installation.

Paths and pathways that generate cell-type heterogeneity and developmental progression in hematopoiesis

Mechanistic studies of Drosophila lymph gland hematopoiesis are limited by the availability of cell-type specific markers. Using a combination of bulk RNA-Seq of FACS-sorted cells, single cell RNA-Seq, and genetic dissection, we identify new blood cell subpopulations along a developmental trajectory with multiple paths to mature cell types. This provides functional insights into key developmental processes and signaling pathways. We highlight metabolism as a driver of development, show that graded Pointed expression allows distinct roles in successive developmental steps, and that mature crystal cells specifically express an alternate isoform of Hypoxia-inducible factor (Hif/Sima). Mechanistically, the Musashi-regulated protein Numb facilitates Sima-dependent non-canonical, and inhibits canonical, Notch signaling. Broadly, we find that prior to making a fate choice, a progenitor selects between alternative, biologically relevant, transitory states allowing smooth transitions reflective of combinatorial expressions rather than stepwise binary decisions. Increasingly, this view is gaining support in mammalian hematopoiesis.