Advances in deep neural networks (DNN) and computer vision (CV) algorithms have made it feasible to extract meaningful insights from large-scale deployments of urban cameras. Tracking an object of interest across the camera network in near real-time is a canonical problem. However, current tracking frameworks have two key limitations: 1) They are monolithic, proprietary, and lack the ability to rapidly incorporate sophisticated tracking models; and 2) They are less responsive to dynamism across wide-area computing resources that include edge, fog and cloud abstractions. We address these gaps using Anveshak, a runtime platform for composing and coordinating distributed tracking applications. It provides a domain-specific dataflow programming model to intuitively compose a tracking application, supporting contemporary CV advances like query fusion and re-identification, and enabling dynamic scoping of the camera-network's search space to avoid wasted computation. We also offer tunable batching and data-dropping strategies for dataflow blocks deployed on distributed resources to respond to network and compute variability. These balance the tracking accuracy, its real-time performance and the active camera-set size. We illustrate the concise expressiveness of the programming model for 4 tracking applications. Our detailed experiments for a network of 1000 camera-feeds on modest resources exhibit the tunable scalability, performance and quality trade-offs enabled by our dynamic tracking, batching and dropping strategies.
The @cite_57 is designed to efficiently deploy DNN models on the edge. It provides a JavaScript API for users to specify the parameters of the DNNs to be used, with the actual DNN implementation abstracted from the end user. While it caters to a wider class of analytics applications, it lacks composability and domain-specific patterns for tracking applications. It offers performance optimizing for the DNN model, but does not consider distributed systems issues, such as batching, dropping and variability of network and compute that we emphasize. Also, not all tracking applications use DNNs, and classic CV algorithms are still relevant @cite_53 .
@cite_57 @cite_53
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The design of DNNs has increasingly focused on reducing the computational complexity in addition to improving accuracy. While emerging DNNs tend to have fewer weights and operations, they also reduce the amount of data reuse with more widely varying layer shapes and sizes. This leads to a diverse set of DNNs, ranging from large ones with high reuse (e.g., AlexNet) to compact ones with high bandwidth requirements (e.g., MobileNet). However, many existing DNN processors depend on certain DNN properties, e.g., a large number of channels, to achieve high performance and energy efficiency and do not have sufficient flexibility to efficiently process a diverse set of DNNs. In this work, we present Eyexam, a performance analysis framework that quantitatively identifies the sources of performance loss in DNN processors. It highlights two architectural bottlenecks in many existing designs. First, their dataflows are not flexible enough to adapt to the varying layer shapes and sizes of different DNNs. Second, their network-on-chip (NoC) can't adapt to support both high data reuse and high bandwidth scenarios. Based on this analysis, we present Eyeriss v2, a high-performance DNN accelerator that adapts to a wide range of DNNs. Eyeriss v2 has a new dataflow, called Row-Stationary Plus (RS+), that enables the spatial tiling of data from all dimensions to fully utilize the parallelism for high performance. To support RS+, it has a low-cost and scalable NoC design, called hierarchical mesh, that connects the high-bandwidth global buffer to the array of processing elements (PEs) in a two-level hierarchy. This enables high-bandwidth data delivery while still being able to harness any available data reuse. Compared with Eyeriss, Eyeriss v2 has a performance increase of 10.4x-17.9x for 256 PEs, 37.7x-71.5x for 1024 PEs, and 448.8x-1086.7x for 16384 PEs on DNNs with widely varying amounts of data reuse. We describe a new formulation of appearance-only SLAM suitable for very large scale place recognition. The system navigates in the space of appearance, assigning each new observation to either a new or a previously visited location, without reference to metric position. The system is demonstrated performing reliable online appearance mapping and loop-closure detection over a 1000âkm trajectory, with mean filter update times of 14âms. The scalability of the system is achieved by defining a sparse approximation to the FAB-MAP model suitable for implementation using an inverted index. Our formulation of the problem is fully probabilistic and naturally incorporates robustness against perceptual aliasing. We also demonstrate that the approach substantially outperforms the standard term-frequency inverse-document-frequency (tf-idf) ranking measure. The 1000âkm data set comprising almost a terabyte of omni-directional and stereo imagery is available for use, and we hope that it will serve as a benchmark for future systems. Big deep neural network (DNN) models trained on large amounts of data have recently achieved the best accuracy on hard tasks, such as image and speech recognition. Training these DNNs using a cluster of commodity machines is a promising approach since training is time consuming and compute-intensive. To enable training of extremely large DNNs, models are partitioned across machines. To expedite training on very large data sets, multiple model replicas are trained in parallel on different subsets of the training examples with a global parameter server maintaining shared weights across these replicas. The correct choice for model and data partitioning and overall system provisioning is highly dependent on the DNN and distributed system hardware characteristics. These decisions currently require significant domain expertise and time consuming empirical state space exploration. This paper develops performance models that quantify the impact of these partitioning and provisioning decisions on overall distributed system performance and scalability. Also, we use these performance models to build a scalability optimizer that efficiently determines the optimal system configuration that minimizes DNN training time. We evaluate our performance models and scalability optimizer using a state-of-the-art distributed DNN training framework on two benchmark applications. The results show our performance models estimate DNN training time with high estimation accuracy and our scalability optimizer correctly chooses the best configurations, minimizing the training time of distributed DNNs. Recently, DNN model compression based on network architecture design, e.g., SqueezeNet, attracted a lot attention. No accuracy drop on image classification is observed on these extremely compact networks, compared to well-known models. An emerging question, however, is whether these model compression techniques hurt DNNs learning ability other than classifying images on a single dataset. Our preliminary experiment shows that these compression methods could degrade domain adaptation (DA) ability, though the classification performance is preserved. Therefore, we propose a new compact network architecture and unsupervised DA method in this paper. The DNN is built on a new basic module Conv-M which provides more diverse feature extractors without significantly increasing parameters. The unified framework of our DA method will simultaneously learn invariance across domains, reduce divergence of feature representations, and adapt label prediction. Our DNN has 4.1M parameters, which is only 6.7 of AlexNet or 59 of GoogLeNet. Experiments show that our DNN obtains GoogLeNet-level accuracy both on classification and DA, and our DA method slightly outperforms previous competitive ones. Put all together, our DA strategy based on our DNN achieves state-of-the-art on sixteen of total eighteen DA tasks on popular Office-31 and Office-Caltech datasets.