John P. Sustersic

A multi-resolution saliency framework to drive foveation

The Human Visual System (HVS) exhibits multi-resolution characteristics, where the fovea is at the highest resolution while the resolution tapers off towards the periphery. Given enough activity at the periphery, the HVS is then capable to foveate to the next region of interest (ROI), to attend to it at full resolution. Saliency models in the past have focused on identifying features that can be used in a bottom-up manner to generate conspicuity maps, which are then combined together to provide regions of fixated interest. However, these models neglect to take into consideration the foveal relation of an object of interest. The model proposed in this work aims to compute saliency as a function of distance from a given fixation point, using a multi-resolution framework. Apart from computational benefits, significant motivation can be found from this work in areas such as visual search, robotics, communications etc.

Window Query Processing with Proxy Cache

A location dependent query (LDQ) result set is valid only in a specific region called the validity region (VR). While limiting the validity of a particular result set to a given area, the VR may also be used in caching implementations to determine if cached results satisfy semantically equivalent queries. Existing LDQ caching schemes rely on the database servers to provide the VR at a cost of high computational overhead. Alternatively, a LDQ proxy cache, which approximates the VR can be employed, freeing the database servers from the high cost of calculating the VR. A LDQ proxy cache architecture is proposed to compute an estimated validity region (EVR) based on the observed querying history at the proxy server. We present an algorithm - Window_EVR - for the LDQ proxy to compute the EVR for a window query result set. The simulation results show that LDQ proxy caching using the Window_EVR algorithm significantly reduces both the window query response time and the workload at the database servers while maintaining query result set accuracy.

An Analysis of Internet Data Update Behaviors

The growing application of caching in Internet applications have heretofore relied largely on qualitative observation and empirical data on the update behavior of Internet data in their design. While it is empirically known that the update behavior of such data is distinctly bimodal, much less is known about the details of these behaviors and the processes that drives them. A detailed study of the composition of modern Web sites that includes in-depth analyses of the changes made to the data of which those sites are composed offers a large potential benefit not only to Internet caching protocol developers but also to a broad cross-section of information technology professionals and researchers. The first results of just such a study are reported in this paper. A variety of popular Internet Web sites were selected and monitored for changes in both composition and content over a period of several weeks. Data collected in this study is then analyzed using traditional stochastic methods. The results of this investigation are summarized and suggested research directions conclude this article

A quality of service (QoS) implementation of Internet cache coherence

Caching has long been employed in computer system architectures to improve performance in terms of reduced memory access times and latencies and hence, to improve throughput at the expense of additional complexity in memory organization and of managing multiple copies of shared data. In traditional large-scale computer architectures, the cache coherency schemes developed permit very large, cache-coherent non-uniform memory access (CC-NUMA) to shared memory spaces. However, these approaches fail when applied to the vastness of the Internet and the growing complexities introduced by mobility. While caching has been successfully employed in specific, limited applications in modern Internet implementations, there has been no general-purpose approach to cache coherency on the Internet. A quality-of-service (QOS) approach is ideally suited for such a general-purpose cache coherence protocol, providing strong consistency for those data items that require it while permitting weaker consistency for less critical data. A statistical analysis of the read/write behavior of typical Internet data is used to suggest a low overhead, inexpensive QOS solution to cache coherency issues on the Internet. An experimental framework studies and verifies the potential of the proposed scheme as a viable solution to cache coherence on both wired and wireless Internet applications.

Multiobjective planning for naval mine counter measures missions

Near-optimal scheduling and allocation for DoD missions is complicated by many factors, including multiple measures of effectiveness, mixed-initiatives, heterogeneity of systems and non-uniformity of homogenous systems; these factors contribute to a complex planning problem with non-linear, combinatorial, and continuous components that is further complicated by information uncertainty. In Navy, mine counter measure missions, planning entails components of the vehicle routing problem with time windows and flexible flowshop scheduling with pre-emptive maintenance. We present a multiobjective mine counter measures problem formulation and describe the non-dominated scheduler, a scheduling programme that parametrically explores continuous dimensions of the decision space, stochastically samples from exponentially large decision spaces, and uses surrogate metrics to bound computational complexity. This provides mission commander with a non-dominated set of alternative plans. This scheduler has been integrated into existing tools and is being evaluated by the US Navy for extension and integration into next-generation mine warfare decision aids.

Quality of service (QoS) in internet cache coherence

Caching has long been employed in computer systems to improve performance at the expense of additional complexity in memory organisation and management. The coherence schemes developed for traditional large-scale systems (CC-NUMA) fail when applied to the vastness of todays mobile internet. A quality of service (QoS) approach is ideally suited for a general-purpose internet cache coherence protocol, providing strong consistency when needed while permitting weaker consistency for less critical data. An inexpensive, QOS solution to internet cache coherence is presented, and an experimental framework is outlined to verify the potential of the proposed scheme as a viable coherence solution for general internet applications.

Towards a unified multiresolution vision model for autonomous ground robots

While remotely operated unmanned vehicles are increasingly a part of everyday life, truly autonomous robots capable of independent operation in dynamic environments have yet to be realized - particularly in the case of ground robots required to interact with humans and their environment. We present a unified multiresolution vision model for this application designed to provide the wide field of view required to maintain situational awareness and sufficient visual acuity to recognize elements of the environment while permitting feasible implementations in real-time vision applications. The model features a kind of color-constant processing through single-opponent color channels and contrast invariant oriented edge detection using a novel implementation of the Combination of Receptive Fields model. The model provides color and edge-based salience assessment, as well as a compressed color image representation suitable for subsequent object identification. We show that bottom-up visual saliency computed using this model is competitive with the current state-of-the-art while allowing computation in a compressed domain and mimicking the human visual system with nearly half (45%) of computational effort focused within the fovea. This method reduces storage requirement of the image pyramid to less than 5% of the full image, and computation in this domain reduces model complexity in terms of both computational costs and memory requirements accordingly. We also quantitatively evaluate the model for its application domain by using it with a camera/lens system with a 185?field of view capturing 3.5M pixel color images by using a tuned salience model to predict human fixations. Generalize the CORF operator for color images for contrast invariant edge detection.Unify center-surround differencing with Serres color image descriptor.Cropped Gaussian Pyramid as a piece-wise linear approximation for foveated vision.Shown competitive performance in visual salience at reduced computational costs.Enabling more complex image processing in real-time, ideal for FPGA implementation.

Non-linear decision making for robust navigation in role based autonomy

A common approach to the robotic path planning problem is to discretize the search space and plan an optimal path using graph search methods. As the optimality criteria becomes more complex it becomes increasingly difficult to optimize the search with respect to each metric being considered. A hybrid path planning system is introduced that supplements the graph search approach with a cognitive architecture. The selected cognitive architecture, Soar, will provide high level reasoning, guiding the implementation of the graph search and reasoning on the results generated. Given scenario-specific context, the hybrid approach will allow for multiple, complex and possibly conflicting criteria to be considered during path generation.