waashk/dblp huggingface dataset:
quantum covariance, quantum fisher information, and the uncertainty relations. in this paper, the relation between quantum covariances and quantum fisher informations is studied. this study is applied to generalize a recently proved uncertainty relation based on quantum fisher information. the proof given here considerably simplifies the previously proposed proofs and leads to more general inequalities.
error exponents for asymmetric two-user discrete memoryless source-channel coding systems. we study the transmission of two discrete memoryless correlated sources, consisting of a common and a private source, over a discrete memoryless multiterminal channel with two transmitters and two receivers. at the transmitter side, the common source is observed by both encoders but the private source can only be accessed by one encoder. at the receiver side, both decoders need to reconstruct the common source, but only one decoder needs to reconstruct the private source. we hence refer to this system by the asymmetric two-user source-channel coding system. we derive a universally achievable lossless joint source-channel coding (jscc) error exponent pair for the two-user system by using a technique which generalizes csiszár's type-packing lemma (1980) for the point-to-point (single-user) discrete memoryless source-channel system. we next investigate the largest convergence rate of asymptotic exponential decay of the system (overall) probability of erroneous transmission, i.e., the system jscc error exponent. we obtain lower and upper bounds for the exponent. as a consequence, we establish a jscc theorem with single-letter characterization and we show that the separation principle holds for the asymmetric two-user scenario. by introducing common randomization, we also provide a formula for the tandem (separate) source-channel coding error exponent. numerical examples show that for a large class of systems consisting of two correlated sources and an asymmetric multiple-access channel with additive noise, the jscc error exponent considerably outperforms the corresponding tandem coding error exponent.
on practical design for joint distributed source and network coding. this paper considers the problem of communicating correlated information from multiple source nodes over a network of noiseless channels to multiple destination nodes, where each destination node wants to recover all sources. the problem involves a joint consideration of distributed compression and network information relaying. although the optimal rate region has been theoretically characterized, it was not clear how to design practical communication schemes with low complexity. this work provides a partial solution to this problem by proposing a low-complexity scheme for the special case with two sources whose correlation is characterized by a binary symmetric channel. our scheme is based on a careful combination of linear syndrome-based slepian-wolf coding and random linear mixing (network coding). it is in general suboptimal; however, its low complexity and robustness to network dynamics make it suitable for practical implementation.
finite-length scaling for iteratively decoded ldpc ensembles. we investigate the behavior of iteratively decoded low-density parity-check (ldpc) codes over the binary erasure channel in the so-called "waterfall region". we show that the performance curves in this region follow a simple scaling law. we conjecture that essentially the same scaling behavior applies in a much more general setting and we provide some empirical evidence to support this conjecture. the scaling law, together with the error floor expressions developed previously, can be used for a fast finite-length optimization.
teleoperation of mobile robots with time-varying delay. this paper proposes a stable control structure for the bilateral teleoperation of mobile robots. the proposed control structure includes a time-delay compensation placed on both the local and remote sites of the teleoperation system. to illustrate the performance and stability of the proposed control structure, experiences on a pioneer 2dx mobile robot teleoperated through a commercial joystick with visual feedback, are shown.
autonomous driving in urban environments: boss and the urban challenge. boss is an autonomous vehicle that uses on-board sensors (global positioning system, lasers, radars, and cameras) to track other vehicles, detect static obstacles, and localize itself relative to a road model. a three-layer planning system combines mission, behavioral, and motion planning to drive in urban environments. the mission planning layer considers which street to take to achieve a mission goal. the behavioral layer determines when to change lanes and precedence at intersections and performs error recovery maneuvers. the motion planning layer selects actions to avoid obstacles while making progress toward local goals. the system was developed from the ground up to address the requirements of the darpa urban challenge using a spiral system development process with a heavy emphasis on regular, regressive system testing. during the national qualification event and the 85-km urban challenge final event, boss demonstrated some of its capabilities, qualifying first and winning the challenge. &copy; 2008 wiley periodicals, inc.
autonomous underground tramming for center-articulated vehicles. this paper describes the design, implementation, and field testing of an infrastructureless system for autonomous tramming (or hauling) of a center-articulated underground mining vehicle. such vehicles are ubiquitous in underground mining, and effective automation of their tramming function has been a sought-after technology for more than a decade. this paper reports on the successful development of a fast, reliable, and robust &ldquo;autotramming&rdquo; technology that does not require the installation of fixed infrastructure. included are descriptions of the chosen control architecture, map-based localization technique, and the results of integration and field testing. &copy; 2008 wiley periodicals, inc.
robust trajectory tracking for a reversing tractor trailer. tractor-trailer reversing is a classical nonlinear control problem in which many of the solutions proposed in the literature perform poorly in the presence of real-world constraints such as steering angle, rate limits, and lags. in this paper we describe a new method in which an inner loop controls the hitch angle of the trailer, creating a virtual articulated vehicle to which existing control techniques can be applied. we provide an analysis of the stability and convergence properties of this control approach, as well as experimental results that illustrate the robustness of this approach to model estimation errors, low-level control loop dynamics, and other disturbances introduced by, for example, state estimation errors. &copy; 2008 wiley periodicals, inc.
cooperative use of unmanned sea surface and micro aerial vehicles at hurricane wilma. on oct. 24, 2005, hurricane wilma, a category 5 storm, made landfall at cape romano, florida. three days later, the center for robot-assisted search and rescue at the university of south florida deployed an isenys helicopter and a prototype unmanned water surface vehicle, aeos-1, to survey damage in parts of marco island, 14 km from landfall. the effort was the first known use of unmanned sea surface vehicles (usvs) for emergency response and established their suitability for the recovery phase of disaster management by detecting damage to seawalls and piers, locating submerged debris (moorings and handrails), and determining safe lanes for sea navigation. it provides a preliminary domain theory of postdisaster port and littoral inspection with unmanned vehicles for use by the human&ndash;robot interaction community. it was also the first known demonstration of the strongly heterogeneous usv&ndash;micro aerial vehicle (mav) team for any domain. the effort identified cooperative uav&ndash;usv strategies and open issues for autonomous operations near structures. the effort showed that the mav provided a much-needed external view for situation awareness and provided spotting for areas to be inspected. concepts of operations for usv damage inspection and usv&ndash;mav cooperation emerged, including a formula for computing the human&ndash;robot ratio: nh = (2 &times; nv) + 1, where nh is the number of humans and nv is the number of vehicles. the outstanding research issues span three areas: challenges for usvs operating near littoral structures, general issues for usv&ndash;mav cooperation, and new applications. it is expected that the lessons learned will be transferrable to defense and homeland safety and security applications, such as port security, and other phases of emergency response, including rescue. &copy; 2008 wiley periodicals, inc.
benchmarking urban six-degree-of-freedom simultaneous localization and mapping. quite a number of approaches for solving the simultaneous localization and mapping (slam) problem exist by now. some of them have recently been extended to mapping environments with six-degree-of-freedom poses, yielding 6d slam approaches. to demonstrate the capabilities of the respective algorithms, it is common practice to present generated maps and successful loop closings in large outdoor environments. unfortunately, it is nontrivial to compare different 6d slam approaches objectively, because ground truth data about the outdoor environments used for demonstration are typically unavailable. we present a novel benchmarking method for generating the ground truth data based on reference maps. the method is then demonstrated by comparing the absolute performance of some previously existing 6d slam algorithms that build a large urban outdoor map. &copy; 2008 wiley periodicals, inc.
on the dynamic version of the minimum hand jerk criterion. this paper is concerned with the problem of trajectory formation of humanlike reaching movements. first, we review conventional criteria of optimality adopted in robotics and computational neuroscience for the prediction of reaching movements and formulate a dynamic version of the minimum hand jerk criteria. we call it a minimum driving force change criterion and check its performance for the free-space movements. next, we test the performance of the new criterion for the movements where the human hand is geometrically constrained by the external environment, and for the movements with flexible objects. the main feature of these movements is that the hand velocity profiles are not always bell shaped. our simulations and initial experimental results show that the minimum driving force change criterion can roughly capture this feature and, therefore, can be a reasonable candidate for modeling of humanlike reaching movements. &copy; 2005 wiley periodicals, inc.
autonomous docking of a smart wheelchair for the automated transport and retrieval system (atrs). the automated transport and retrieval system (atrs) represents a technology-based alternative to van conversions for automobile drivers in wheelchairs. rather than requiring dramatic, permanent, and expensive modifications to the host vehicle, atrs employs robotics and automation technologies and can be integrated noninvasively into a standard minivan or sport utility vehicle. at the core of atrs is a &ldquo;smart&rdquo; wheelchair system that autonomously navigates between the driver's position and a powered lift at the rear of the vehicle, eliminating the need for an attendant. from an automation perspective, autonomously docking the wheelchair onto the lift platform presented the most significant technical challenge due to limited clearance between the chair wheels and the lift platform rails. to solve the docking task, we employed a light detection and ranging (lidar)&ndash;based approach for wheelchair localization coupled with a hybrid motion controller design. extensive testing from the localization subsystem to the complete atrs was conducted under representative usage conditions. this included 3 days of public demonstrations indoors at the world congress on disabilities, where potential end users were able to evaluate the system. in this environment, atrs performed more than 300 consecutive cycles without failure. during 2 days of outdoor reliability testing, 97.5&percnt; docking reliability was observed. the system is scheduled to enter the commercial market in 2008. &copy; 2008 wiley periodicals, inc.
biologically inspired climbing with a hexapedal robot. this paper presents an integrated, systems-level view of several novel design and control features associated with the biologically inspired, hexapedal, rise (robots in scansorial environments) robot. rise is the first legged machine capable of locomotion on both the ground and a variety of vertical building surfaces including brick, stucco, and crushed stone at speeds up to 4 cm-s, quietly and without the use of suction, magnets, or adhesives. it achieves these capabilities through a combination of bioinspired and traditional design methods. this paper describes the design process and specifically addresses body morphology, hierarchical compliance in the legs and feet, and sensing and control systems that enable robust and reliable climbing on difficult surfaces. experimental results illustrate the effects of various behaviors on climbing performance and demonstrate the robot's ability to climb reliably for long distances. &copy; 2008 wiley periodicals, inc.
a practical approach to robotic design for the darpa urban challenge. this article presents a practical approach to engineering a robot to effectively navigate in an urban environment. inherent in this approach is the use of relatively simple sensors, actuators, and processors to generate robot vision, intelligence, and planning. sensor data are fused from multiple low-cost, two-dimensional laser scanners with an innovative rotational mount to provide three-dimensional coverage with image processing using both range and intensity data. information is combined with doppler radar returns to yield a world view processed by a context-based reasoning control system to yield tactical mission commands forwarded to traditional proportional-integral-derivative (pid) control loops. as an example of simplicity and robustness, steering control successfully utilized a relatively simple follow-the-carrot guidance approach that has been successfully demonstrated at speeds of 60 mph (97 km-h). the approach yielded a robot that reached the finals of the urban challenge and completed approximately 2 h of the event before being forced to withdraw as a result of a global positioning system data failure. &copy; 2008 wiley periodicals, inc.
monte carlo localization in outdoor terrains using multilevel surface maps. we propose a novel combination of techniques for robustly estimating the position of a mobile robot in outdoor environments using range data. our approach applies a particle filter to estimate the full six-dimensional state of the robot and utilizes multilevel surface maps, which, in contrast to standard elevation maps, allow the robot to represent vertical structures and multiple levels in the environment. we describe probabilistic motion and sensor models to calculate the proposal distribution and to evaluate the likelihood of observations. we furthermore describe an active localization approach that actively selects the sensor orientation of the two-dimensional laser range scanner to improve the localization results. to efficiently calculate the appropriate orientation, we apply a clustering operation on the particles and evaluate potential orientations on the basis of these clusters. experimental results obtained with a mobile robot in large-scale outdoor environments indicate that our approach yields robust and accurate position estimates. the experiments also demonstrate that multilevel surface maps lead to a significantly better localization performance than standard elevation maps. they additionally show that further accuracy is obtained from the active sensing approach. &copy; 2008 wiley periodicals, inc.
long-baseline acoustic navigation for under-ice autonomous underwater vehicle operations. the recent arctic gakkel vents expedition (agave) to the arctic ocean's gakkel ridge (july-august 2007) aboard the swedish icebreaker i-b oden employed autonomous underwater vehicles (auvs) for water-column and ocean bottom surveys. these surveys were unique among auv operations to date in requiring georeferenced navigation in proximity to the seafloor beneath permanent and moving ice cover. we report results for long-baseline (lbl) acoustic navigation during autonomous under-ice surveys near the seafloor and adaptation of the lbl concept for several typical operational situations including navigation in proximity to the ship during vehicle recoveries. fixed seafloor transponders were free-fall deployed from the ship for deep positioning. the ship's helicopter collected acoustic travel times from several locations to georeference the transponders' locations, subject to the availability of openings in the ice. two shallow beacons suspended from the ship provided near-surface spherical navigation in ship-relative coordinates. during routine recoveries, we used this system to navigate the vehicles into open water near the ship before commanding them to surface. in cases in which a vehicle was impaired, its position was still determined acoustically through some combination of its acoustic modem, the fixed seafloor transponders, the ship-deployed transponders, and an onboard backup relay transponder. the techniques employed included ranging adapted for a moving origin and hyperbolic navigation. &copy; 2008 wiley periodicals, inc.
team annieway's autonomous system for the 2007 darpa urban challenge. this paper reports on annieway, an autonomous vehicle that is capable of driving through urban scenarios and that successfully entered the finals of the 2007 darpa urban challenge competition. after describing the main challenges imposed and the major hardware components, we outline the underlying software structure and focus on selected algorithms. environmental perception mainly relies on a recent laser scanner that delivers both range and reflectivity measurements. whereas range measurements are used to provide three-dimensional scene geometry, measuring reflectivity allows for robust lane marker detection. mission and maneuver planning is conducted using a hierarchical state machine that generates behavior in accordance with california traffic laws. we conclude with a report of the results achieved during the competition. &copy; 2008 wiley periodicals, inc.
terrain-based vehicle orientation estimation combining vision and inertial measurements. a novel method for estimating vehicle roll, pitch, and yaw using machine vision and inertial sensors is presented that is based on matching images captured from an on-vehicle camera to a rendered representation of the surrounding terrain obtained from a three-dimensional (3d) terrain map. u.s. geographical survey digital elevation maps were used to create a 3d topology map of the geography surrounding the vehicle, and it is assumed in this work that large segments of the surrounding terrain are visible, particularly the horizon lines. the horizon lines seen in the captured video from the vehicle are compared to the horizon lines obtained from a rendered geography, allowing absolute comparisons between rendered and actual scene in roll, pitch, and yaw. a kinematic kalman filter modeling an inertial navigation system then uses the scene matching to generate filtered estimates of orientation. numerical simulations verify the performance of the kalman filter. experiments using an instrumented vehicle operating at the test track of the pennsylvania transportation institute were performed to check the validity of the method. when compared to estimates from a global positioning system-inertial measurement unit (imu) system, the roll, pitch, and yaw estimates from vision-imu kalman filter show an agreement with a (2&sigma;) bound of 0.5, 0.26, and 0.8 deg, respectively. &copy; 2008 wiley periodicals, inc.
development and application of an autonomous unmanned aerial vehicle for precise aerobiological sampling above agricultural fields. remote-controlled (rc) unmanned aerial vehicles (uavs) have been used to study the movement of agricultural threat agents (e.g., plant and animal pathogens, invasive weeds, and exotic insects) above crop fields, but these rc uavs are operated entirely by a ground-based pilot and often demonstrate large fluctuations in sampling height, sampling pattern, and sampling speed. in this paper, we describe the development and application of an autonomous uav for precise aerobiological sampling tens to hundreds of meters above agricultural fields. we equipped a senior telemaster uav with four aerobiological sampling devices and a micropilot-based autonomous system, and we conducted 25 sampling flights for potential agricultural threat agents at virginia tech's kentland farm. to determine the most appropriate sampling path for aerobiological sampling above crop fields with an autonomous uav, we explored five different sampling patterns, including multiple global positioning system (gps) waypoints plotted over a variety of spatial scales. an orbital sampling pattern around a single gps waypoint exhibited high positional accuracy and produced altitude standard deviations ranging from 1.6 to 2.8 m. autonomous uavs have the potential to extend the range of aerobiological sampling, improve positional accuracy of sampling paths, and enable coordinated flight with multiple uavs sampling at different altitudes. &copy; 2008 wiley periodicals, inc.
compact image stabilization system using camera posture information. a teleoperated robot that works in unstructured environments such as disaster sites is mainly controlled based on images obtained from cameras mounted on the robot. because the robot runs on rough terrains, the images from the mounted camera are nonsteady ones. these nonsteady images will make it difficult for the operator to understand the surrounding information and will cause the camera motion sickness. we have developed an image stabilization system using camera posture information for a mobile robot that moves on uneven terrains. because the camera posture information is detected by a three-dimensional-motion sensor separately from the camera image, this system works even in bad light condition environments and is robust for light condition changes. the wide-field-of-view images obtained by the fish-eye-lens camera are used to handle a large-amplitude disturbance. the sphere mapping and the image shifting of a region of &copy; 2008 wiley periodicals, inc.
team cornell's skynet: robust perception and planning in an urban environment. team cornell's skynet is an autonomous chevrolet tahoe built to compete in the 2007 darpa urban challenge. skynet consists of many unique subsystems, including actuation and power distribution designed in-house, a tightly coupled attitude and position estimator, a novel obstacle detection and tracking system, a system for augmenting position estimates with vision-based detection algorithms, a path planner based on physical vehicle constraints and a nonlinear optimization routine, and a state-based reasoning agent for obeying traffic laws. this paper describes these subsystems in detail before discussing the system's overall performance in the national qualifying event and the urban challenge. logged data recorded at the national qualifying event and the urban challenge are presented and used to analyze the system's performance. &copy; 2008 wiley periodicals, inc.