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Sample records for adaptive paths give

  1. Adaptively Ubiquitous Learning in Campus Math Path

    Science.gov (United States)

    Shih, Shu-Chuan; Kuo, Bor-Chen; Liu, Yu-Lung

    2012-01-01

    The purposes of this study are to develop and evaluate the instructional model and learning system which integrate ubiquitous learning, computerized adaptive diagnostic testing system and campus math path learning. The researcher first creates a ubiquitous learning environment which is called "adaptive U-learning math path system". This…

  2. An Adaptive Path Planning Algorithm for Cooperating Unmanned Air Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, C.T.; Roberts, R.S.

    2000-09-12

    An adaptive path planning algorithm is presented for cooperating Unmanned Air Vehicles (UAVs) that are used to deploy and operate land-based sensor networks. The algorithm employs a global cost function to generate paths for the UAVs, and adapts the paths to exceptions that might occur. Examples are provided of the paths and adaptation.

  3. Adaptive robot path planning in changing environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P.C.

    1994-08-01

    Path planning needs to be fast to facilitate real-time robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To overcome this difficulty, we present an adaptive algorithm that uses past experience to speed up future performance. It is a learning algorithm suitable for incrementally-changing environments such as those encountered in manufacturing of evolving products and waste-site remediation. The algorithm allows the robot to adapt to its environment by having two experience manipulation schemes: For minor environmental change, we use an object-attached experience abstraction scheme to increase the flexibility of the learned experience; for major environmental change, we use an on-demand experience repair scheme to retain those experiences that remain valid and useful. Using this algorithm, we can effectively reduce the overall robot planning time by re-using the computation result for one task to plan a path for another.

  4. Adaptive path planning: Algorithm and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pang C.

    1993-03-01

    Path planning has to be fast to support real-time robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To alleviate this problem, we present a learning algorithm that uses past experience to enhance future performance. The algorithm relies on an existing path planner to provide solutions to difficult tasks. From these solutions, an evolving sparse network of useful subgoals is learned to support faster planning. The algorithm is suitable for both stationary and incrementally-changing environments. To analyze our algorithm, we use a previously developed stochastic model that quantifies experience utility. Using this model, we characterize the situations in which the adaptive planner is useful, and provide quantitative bounds to predict its behavior. The results are demonstrated with problems in manipulator planning. Our algorithm and analysis are sufficiently general that they may also be applied to task planning or other planning domains in which experience is useful.

  5. ACO in e-Learning: Towards an adaptive learning path

    Directory of Open Access Journals (Sweden)

    Pushpa. M

    2012-03-01

    Full Text Available Today we are in an era where drastic advancements in networking and information technology are in action. The learning process has also taken these advancements, as a result of which e-learning came to thescene. Personalization in e-learning will improve the performance of the system. Recent researches are concentrating on providing adaptability to the learning management systems, depending upon the varying user needs and contexts. Adaptability can be provided at different levels .Providing an adaptive learning path according to the context of the learners’ is an important issue. An optimal adaptive learning path will help the learners in reducing the cognitive overload and disorientation, and thereby improving the efficiency of the Learning Management System (LMS. Ant Colony Optimization (ACO is a widely accepted technique since it provides an adaptive learning path to the learners. Meta-heuristic which is used in intelligent tutoring systems provides the learning path in an adaptive way. The most interesting feature of ACO is its adaptation and robustness in an environment where the learning materials and learners are changing frequently. In this paper we can have a look through the existing ACO approaches towards providing an adaptive learning path and an introduction towards an enhanced attribute ant for making the e-learning system more adaptive.

  6. Spatial Path Following for AUVs Using Adaptive Neural Network Controllers

    Directory of Open Access Journals (Sweden)

    Jiajia Zhou

    2013-01-01

    Full Text Available The spatial path following control problem of autonomous underwater vehicles (AUVs is addressed in this paper. In order to realize AUVs’ spatial path following control under systemic variations and ocean current, three adaptive neural network controllers which are based on the Lyapunov stability theorem are introduced to estimate uncertain parameters of the vehicle’s model and unknown current disturbances. These controllers are designed to guarantee that all the error states in the path following system are asymptotically stable. Simulation results demonstrated that the proposed controller was effective in reducing the path following error and was robust against the disturbances caused by vehicle's uncertainty and ocean currents.

  7. Adaptive path planning: Algorithm and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pang C.

    1995-03-01

    To address the need for a fast path planner, we present a learning algorithm that improves path planning by using past experience to enhance future performance. The algorithm relies on an existing path planner to provide solutions difficult tasks. From these solutions, an evolving sparse work of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a framework in which a slow but effective planner may be improved both cost-wise and capability-wise by a faster but less effective planner coupled with experience. We analyze algorithm by formalizing the concept of improvability and deriving conditions under which a planner can be improved within the framework. The analysis is based on two stochastic models, one pessimistic (on task complexity), the other randomized (on experience utility). Using these models, we derive quantitative bounds to predict the learning behavior. We use these estimation tools to characterize the situations in which the algorithm is useful and to provide bounds on the training time. In particular, we show how to predict the maximum achievable speedup. Additionally, our analysis techniques are elementary and should be useful for studying other types of probabilistic learning as well.

  8. Robust Adaptive Photon Tracing using Photon Path Visibility

    DEFF Research Database (Denmark)

    Hachisuka, Toshiya; Jensen, Henrik Wann

    2011-01-01

    We present a new adaptive photon tracing algorithm which can handle illumination settings that are considered difficult for photon tracing approaches such as outdoor scenes, close-ups of a small part of an illuminated region, and illumination coming through a small gap. The key contribution in our...... algorithm is the use of visibility of photon path as the importance function which ensures that our sampling algorithm focuses on paths that are visible from the given viewpoint. Our sampling algorithm builds on two recent developments in Markov chain Monte Carlo methods: adaptive Markov chain sampling...... and replica exchange. Using these techniques, each photon path is adaptively mutated and it explores the sampling space efficiently without being stuck at a local peak of the importance function. We have implemented this sampling approach in the progressive photon mapping algorithm which provides visibility...

  9. Line-of-Sight Path Following for Dubins Paths with Adaptive Sideslip Compensation of Drift Forces

    DEFF Research Database (Denmark)

    Fossen, Thor Inge; Pettersen, Kristin Ytterstad; Galeazzi, Roberto

    2015-01-01

    guidance law is intended for maneuvering in the horizontal-plane at given speeds and typical applications are marine craft, autonomous underwater vehicles (AUVs), unmanned aerial vehicles (UAVs) as well as other vehicles and craft where the goal is to follow a predefined parametrized curve without time......We present a nonlinear adaptive path-following controller that compensates for drift forces through vehicle sideslip. Vehicle sideslip arises during path following when the vehicle is subject to drift forces caused by ocean currents, wind and waves. The proposed algorithm is motivated by a lineof...... constraints. Two vehicle cases studies are included to verify the theoretical results....

  10. Path Planning Algorithms for the Adaptive Sensor Fleet

    Science.gov (United States)

    Stoneking, Eric; Hosler, Jeff

    2005-01-01

    The Adaptive Sensor Fleet (ASF) is a general purpose fleet management and planning system being developed by NASA in coordination with NOAA. The current mission of ASF is to provide the capability for autonomous cooperative survey and sampling of dynamic oceanographic phenomena such as current systems and algae blooms. Each ASF vessel is a software model that represents a real world platform that carries a variety of sensors. The OASIS platform will provide the first physical vessel, outfitted with the systems and payloads necessary to execute the oceanographic observations described in this paper. The ASF architecture is being designed for extensibility to accommodate heterogenous fleet elements, and is not limited to using the OASIS platform to acquire data. This paper describes the path planning algorithms developed for the acquisition phase of a typical ASF task. Given a polygonal target region to be surveyed, the region is subdivided according to the number of vessels in the fleet. The subdivision algorithm seeks a solution in which all subregions have equal area and minimum mean radius. Once the subregions are defined, a dynamic programming method is used to find a minimum-time path for each vessel from its initial position to its assigned region. This path plan includes the effects of water currents as well as avoidance of known obstacles. A fleet-level planning algorithm then shuffles the individual vessel assignments to find the overall solution which puts all vessels in their assigned regions in the minimum time. This shuffle algorithm may be described as a process of elimination on the sorted list of permutations of a cost matrix. All these path planning algorithms are facilitated by discretizing the region of interest onto a hexagonal tiling.

  11. Variance Analysis and Adaptive Sampling for Indirect Light Path Reuse

    Institute of Scientific and Technical Information of China (English)

    Hao Qin; Xin Sun; Jun Yan; Qi-Ming Hou; Zhong Ren; Kun Zhou

    2016-01-01

    In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes — in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the covariance of the reconstruction samples dominates the estimation variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the covariance. We also find that the covariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the covariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost.

  12. A morphological adaptation approach to path planning inspired by slime mould

    Science.gov (United States)

    Jones, Jeff

    2015-04-01

    Path planning is a classic problem in computer science and robotics which has recently been implemented in unconventional computing substrates such as chemical reaction-diffusion computers. These novel computing schemes utilise the parallel spatial propagation of information and often use a two-stage method involving diffusive propagation to discover all paths and a second stage to highlight or visualise the path between two particular points in the arena. The true slime mould Physarum polycephalum is known to construct efficient transport networks between nutrients in its environment. These networks are continuously remodelled as the organism adapts its body plan to changing spatial stimuli. It can be guided towards attractant stimuli (nutrients, warm regions) and it avoids locations containing hazardous stimuli (light irradiation, repellents, or regions occupied by predatory threats). Using a particle model of slime mould we demonstrate scoping experiments which explore how path planning may be performed by morphological adaptation. We initially demonstrate simple path planning by a shrinking blob of virtual plasmodium between two attractant sources within a polygonal arena. We examine the case where multiple paths are required and the subsequent selection of a single path from multiple options. Collision-free paths are implemented via repulsion from the borders of the arena. Finally, obstacle avoidance is implemented by repulsion from obstacles as they are uncovered by the shrinking blob. These examples show proof-of-concept results of path planning by morphological adaptation which complement existing research on path planning in novel computing substrates.

  13. Adaptive management of social-ecological systems: the path forward

    Science.gov (United States)

    Allen, Craig R.

    2015-01-01

    Adaptive management remains at the forefront of environmental management nearly 40 years after its original conception, largely because we have yet to develop other methodologies that offer the same promise. Despite the criticisms of adaptive management and the numerous failed attempts to implement it, adaptive management has yet to be replaced with a better alternative. The concept persists because it is simple, allows action despite uncertainty, and fosters learning. Moving forward, adaptive management of social-ecological systems provides policymakers, managers and scientists a powerful tool for managing for resilience in the face of uncertainty.

  14. Adaptive Management of Social-Ecological Systems: The Path Forward

    Science.gov (United States)

    Adaptive management remains at the forefront of environmental management nearly 40 years after its original conception, largely because we have yet to develop other methodologies that offer the same promise. Despite the criticisms of adaptive management and the numerous failed at...

  15. An adaptive dual-optimal path-planning technique for unmanned air vehicles

    Directory of Open Access Journals (Sweden)

    Whitfield Clifford A.

    2016-01-01

    Full Text Available A multi-objective technique for unmanned air vehicle path-planning generation through task allocation has been developed. The dual-optimal path-planning technique generates real-time adaptive flight paths based on available flight windows and environmental influenced objectives. The environmentally-influenced flight condition determines the aircraft optimal orientation within a downstream virtual window of possible vehicle destinations that is based on the vehicle’s kinematics. The intermittent results are then pursued by a dynamic optimization technique to determine the flight path. This path-planning technique is a multi-objective optimization procedure consisting of two goals that do not require additional information to combine the conflicting objectives into a single-objective. The technique was applied to solar-regenerative high altitude long endurance flight which can benefit significantly from an adaptive real-time path-planning technique. The objectives were to determine the minimum power required flight paths while maintaining maximum solar power for continual surveillance over an area of interest (AOI. The simulated path generation technique prolonged the flight duration over a sustained turn loiter flight path by approximately 2 months for a year of flight. The potential for prolonged solar powered flight was consistent for all latitude locations, including 2 months of available flight at 60° latitude, where sustained turn flight was no longer capable.

  16. Adaptive neural control for cooperative path following of marine surface vehicles: state and output feedback

    Science.gov (United States)

    Wang, H.; Wang, D.; Peng, Z. H.

    2016-01-01

    This paper addresses the cooperative path-following problem of multiple marine surface vehicles subject to dynamical uncertainties and ocean disturbances induced by unknown wind, wave and ocean current. The control design falls neatly into two parts. One is to steer individual marine surface vehicle to track a predefined path and the other is to synchronise the along-path speed and path variables under the constraints of an underlying communication network. Within these two formulations, a robust adaptive path-following controller is first designed for individual vehicles based on backstepping and neural network techniques. Then, a decentralised synchronisation control law is derived by means of consensus on along-path speed and path variables based on graph theory. The distinct feature of this design lies in that synchronised path following can be reached for any undirected connected communication graphs without accurate knowledge of the model. This result is further extended to the output feedback case, where an observer-based cooperative path-following controller is developed without measuring the velocity of each vehicle. For both designs, rigorous theoretical analysis demonstrate that all signals in the closed-loop system are semi-global uniformly ultimately bounded. Simulation results validate the performance and robustness improvement of the proposed strategy.

  17. An adaptation of Krylov subspace methods to path following

    Energy Technology Data Exchange (ETDEWEB)

    Walker, H.F. [Utah State Univ., Logan, UT (United States)

    1996-12-31

    Krylov subspace methods at present constitute a very well known and highly developed class of iterative linear algebra methods. These have been effectively applied to nonlinear system solving through Newton-Krylov methods, in which Krylov subspace methods are used to solve the linear systems that characterize steps of Newton`s method (the Newton equations). Here, we will discuss the application of Krylov subspace methods to path following problems, in which the object is to track a solution curve as a parameter varies. Path following methods are typically of predictor-corrector form, in which a point near the solution curve is {open_quotes}predicted{close_quotes} by some easy but relatively inaccurate means, and then a series of Newton-like corrector iterations is used to return approximately to the curve. The analogue of the Newton equation is underdetermined, and an additional linear condition must be specified to determine corrector steps uniquely. This is typically done by requiring that the steps be orthogonal to an approximate tangent direction. Augmenting the under-determined system with this orthogonality condition in a straightforward way typically works well if direct linear algebra methods are used, but Krylov subspace methods are often ineffective with this approach. We will discuss recent work in which this orthogonality condition is imposed directly as a constraint on the corrector steps in a certain way. The means of doing this preserves problem conditioning, allows the use of preconditioners constructed for the fixed-parameter case, and has certain other advantages. Experiments on standard PDE continuation test problems indicate that this approach is effective.

  18. STDP in adaptive neurons gives close-to-optimal information transmission

    Directory of Open Access Journals (Sweden)

    Guillaume Hennequin

    2010-12-01

    Full Text Available Spike-frequency adaptation is known to enhance the transmission of information in sensory spiking neurons, by rescaling the dynamic range for input processing, matching it to the temporal statistics of the sensory stimulus. Achieving maximal information transmission has also been recently postulated as a role for Spike-Timing Dependent Plasticity (STDP. However, the link between optimal plasticity and STDP in cortex remains loose, and so does the relationship between STDP and adaptation processes. We investigate how STDP, as described by recent minimal models derived from experimental data, influences the quality of information transmission in an adapting neuron. We show that a phenomenological model based on triplets of spikes yields almost the same information rate as an optimal model specially designed to this end. In contrast, the standard pair-based model of STDP does not improve information transmission as much. This result holds not only for additive STDP with hard weight bounds, known to produce bimodal distributions of synaptic weights, but also for weight-dependent STDP in the context of unimodal but skewed weight distributions. We analyze the similarities between the triplet model and the optimal learning rule, and find that the triplet effect is an important feature of the optimal model when the neuron is adaptive. If STDP is optimized for information transmission, it must take into account the dynamical properties of the postsynaptic cell, which might explain the target-cell specificity of STDP. In particular, it accounts for the differences found in vitro between STDP at excitatory synapses onto principal cells and those onto fast-spiking interneurons.

  19. Adaptive robust dissipative designs on straight path control for underactuated ships

    Institute of Scientific and Technical Information of China (English)

    Li Tieshan; Yang Yansheng; Hong Biguang

    2006-01-01

    An adaptive robust control algorithm for ship straight path control system in the presence of both modeling uncertainties and the bounded disturbances is proposed. Motivated by the backstepping approach, the algorithm is developed by using the dissipation theory, such that the resulting closed-loop system is both strictly dissipative and asymptotically adaptively stable for all admissible uncertainties. Also, it is able to steer an underactuated ship along a prescribed straight path with ultimate bounds under external disturbances induced by wave, wind and ocean current. When there are no disturbances, the straight path control can be implemented in a locally asymptotically stable manner. Simulation results on an ocean-going training ship ‘YULONG’ are presented to validate the effectiveness of the algorithm.

  20. Non-common path aberration correction in an adaptive optics scanning ophthalmoscope.

    Science.gov (United States)

    Sulai, Yusufu N; Dubra, Alfredo

    2014-09-01

    The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth.

  1. A note on "Multicriteria adaptive paths in stochastic, time-varying networks"

    DEFF Research Database (Denmark)

    Pretolani, Daniele; Nielsen, Lars Relund; Andersen, Kim Allan

    In a recent paper, Opasanon and Miller-Hooks study multicriteria adaptive paths in stochastic time-varying networks. They propose a label correcting algorithm for finding the full set of efficient strategies. In this note we show that their algorithm is not correct, since it is based on a property...

  2. Online adaptation of path formation in UAV search-and-identify missions

    NARCIS (Netherlands)

    Willigen, W.H. van; Schut, M.C.; Eiben, A.E.; Kester, L.J.H.M.

    2011-01-01

    In this paper, we propose a technique for optimisation and online adaptation of search paths of unmanned aerial vehicles (UAVs) in search-and-identify missions. In these missions, a UAV has the objective to search for targets and to identify those. We extend earlier work that was restricted to offli

  3. Giving Context to the Physician Competency Reference Set: Adapting to the Needs of Diverse Populations

    Science.gov (United States)

    Eckstrand, Kristen L.; Potter, Jennifer; Bayer, Carey Roth; Englander, Robert

    2016-01-01

    Delineating the requisite competencies of a 21st-century physician is the first step in the paradigm shift to competency-based medical education. Over the past two decades, more than 150 lists of competencies have emerged. In a synthesis of these lists, the Physician Competency Reference Set (PCRS) provided a unifying framework of competencies that define the general physician. The PCRS is not context or population specific; however, competently caring for certain underrepresented populations or specific medical conditions can require more specific context. Previously developed competency lists describing care for these populations have been disconnected from an overarching competency framework, limiting their uptake. To address this gap, the Association of American Medical Colleges Advisory Committee on Sexual Orientation, Gender Identity, and Sex Development adapted the PCRS by adding context- and content-specific qualifying statements to existing PCRS competencies to better meet the needs of diverse patient populations. This Article describes the committee’s process in developing these qualifiers of competence. To facilitate widespread adoption of the contextualized competencies in U.S. medical schools, the committee used an established competency framework to develop qualifiers of competence to improve the health of individuals who are lesbian, gay, bisexual, transgender; gender nonconforming; or born with differences in sexual development. This process can be applied to other underrepresented populations or medical conditions, ensuring that relevant topics are included in medical education and, ultimately, health care outcomes are improved for all patients inclusive of diversity, background, and ability. PMID:26796092

  4. Giving Context to the Physician Competency Reference Set: Adapting to the Needs of Diverse Populations.

    Science.gov (United States)

    Eckstrand, Kristen L; Potter, Jennifer; Bayer, Carey Roth; Englander, Robert

    2016-07-01

    Delineating the requisite competencies of a 21st-century physician is the first step in the paradigm shift to competency-based medical education. Over the past two decades, more than 150 lists of competencies have emerged. In a synthesis of these lists, the Physician Competency Reference Set (PCRS) provided a unifying framework of competencies that define the general physician. The PCRS is not context or population specific; however, competently caring for certain underrepresented populations or specific medical conditions can require more specific context. Previously developed competency lists describing care for these populations have been disconnected from an overarching competency framework, limiting their uptake. To address this gap, the Association of American Medical Colleges Advisory Committee on Sexual Orientation, Gender Identity, and Sex Development adapted the PCRS by adding context- and content-specific qualifying statements to existing PCRS competencies to better meet the needs of diverse patient populations. This Article describes the committee's process in developing these qualifiers of competence. To facilitate widespread adoption of the contextualized competencies in U.S. medical schools, the committee used an established competency framework to develop qualifiers of competence to improve the health of individuals who are lesbian, gay, bisexual, transgender; gender nonconforming; or born with differences in sexual development. This process can be applied to other underrepresented populations or medical conditions, ensuring that relevant topics are included in medical education and, ultimately, health care outcomes are improved for all patients inclusive of diversity, background, and ability.

  5. IIR filtering based adaptive active vibration control methodology with online secondary path modeling using PZT actuators

    Science.gov (United States)

    Boz, Utku; Basdogan, Ipek

    2015-12-01

    Structural vibrations is a major cause for noise problems, discomfort and mechanical failures in aerospace, automotive and marine systems, which are mainly composed of plate-like structures. In order to reduce structural vibrations on these structures, active vibration control (AVC) is an effective approach. Adaptive filtering methodologies are preferred in AVC due to their ability to adjust themselves for varying dynamics of the structure during the operation. The filtered-X LMS (FXLMS) algorithm is a simple adaptive filtering algorithm widely implemented in active control applications. Proper implementation of FXLMS requires availability of a reference signal to mimic the disturbance and model of the dynamics between the control actuator and the error sensor, namely the secondary path. However, the controller output could interfere with the reference signal and the secondary path dynamics may change during the operation. This interference problem can be resolved by using an infinite impulse response (IIR) filter which considers feedback of the one or more previous control signals to the controller output and the changing secondary path dynamics can be updated using an online modeling technique. In this paper, IIR filtering based filtered-U LMS (FULMS) controller is combined with online secondary path modeling algorithm to suppress the vibrations of a plate-like structure. The results are validated through numerical and experimental studies. The results show that the FULMS with online secondary path modeling approach has more vibration rejection capabilities with higher convergence rate than the FXLMS counterpart.

  6. Adaptive path planning for unmanned aerial vehicles based on bi-level programming and variable planning time interval

    Institute of Scientific and Technical Information of China (English)

    Liu Wei; Zheng Zheng; Cai Kaiyuan

    2013-01-01

    This paper presents an adaptive path planner for unmanned aerial vehicles (UAVs) to adapt a real-time path search procedure to variations and fluctuations of UAVs' relevant performances,with respect to sensory capability,maneuverability,and flight velocity limit.On the basis of a novel adaptability-involved problem statement,bi-level programming (BLP) and variable planning step techniques are introduced to model the necessary path planning components and then an adaptive path planner is developed for the purpose of adaptation and optimization.Additionally,both probabilistic-risk-based obstacle avoidance and performance limits are described as path search constraints to guarantee path safety and navigability.A discrete-search-based path planning solution,embedded with four optimization strategies,is especially designed for the planner to efficiently generate optimal flight paths in complex operational spaces,within which different surface-to-air missiles (SAMs) are deployed.Simulation results in challenging and stochastic scenarios firstly demonstrate the effectiveness and efficiency of the proposed planner,and then verify its great adaptability and relative stability when planning optimal paths for a UAV with changing or fluctuating performances.

  7. Aircraft-on-ground path following control by dynamical adaptive backstepping

    Institute of Scientific and Technical Information of China (English)

    Chen Bihua; Jiao Zongxia; Shuzhi Sam Ge

    2013-01-01

    The necessity of improving the air traffic and reducing the aviation emissions drives to investigate automatic steering for aircraft to effectively roll on the ground.This paper addresses the path following control problem of aircraft-on-ground and focuses on the task that the aircraft is required to follow the desired path on the runway by nose wheel automatic steering.The proposed approach is based on dynamical adaptive backstepping so that the system model does not have to be transformed into a canonical triangular form which is necessary in conventional backstepping design.This adaptive controller performs well despite the lack of information on the aerodynamic load and the tire cornering stiffness parameters.Simulation results clearly demonstrate the advantages and effectiveness of the proposed approach.

  8. Adaptive PSO using random inertia weight and its application in UAV path planning

    Science.gov (United States)

    Zhu, Hongguo; Zheng, Changwen; Hu, Xiaohui; Li, Xiang

    2008-10-01

    A novel particle swarm optimization algorithm, called APSO_RW is presented. Random inertia weight improves its global optimization performance and an adaptive reinitialize mechanism is used when the global best particle is detected to be trapped. The new algorithm is tested on a set of benchmark functions and experimental results show its efficiency. APSO_RW is later applied in UAV (Unmanned Aerial Vehicle) path planning.

  9. Adaptive and less-complex path-planning behavior for mobile robots

    Science.gov (United States)

    Mantegh, Iraj; Jenkin, Michael R. M.; Goldenberg, Andrew A.

    1998-01-01

    The objective of path planing is to find a sequence of states that a system has to visit in order to attain the goal state. Because of their real-time efficiency, potential field methods present a powerful heuristic to guide this search. However, potential field approaches can not guarantee goal attainability. They are often referred to as 'local methods' and are used in conjunction with a global path planning method to ensure completeness of the path planning algorithm. The present work introduces a novel methodology for path planing which combines the real- time efficiency of potential field methods with goal-attainability characteristics of global methods. The algorithm of this work is: 1) free from local minima, ii) capable of considering arbitrary-shaped obstacles, iii) computationally less complex than previous search methods; and iv) able to handle obstacle avoidance and goal attainability at the same time. At the first step a new probabilistic scheme, based on absorbing Markov chains, is presented for global planning inside structured environments, such as office, etc. The potential field method is then reformulated for adaptive path planning among modeled and new obstacles.

  10. E-Learning and Personalized Learning Path: A Proposal Based on the Adaptive Educational Hypermedia System

    Directory of Open Access Journals (Sweden)

    Francesco Colace

    2014-03-01

    Full Text Available The E-Learning is becoming an effective approach for the improving of quality of learning. Many institutions are adopting this approach both to improve their traditional courses both to increase the potential audience. In the last period great attention is paid in the introduction of methodologies and techniques for the adaptation of learning process to the real needs of students. In this scenario the Adaptive Educational Hypermedia System can be an effective approach. Adaptive hypermedia is a promising area of research at the crossroads of hypermedia and adaptive systems. One of the most important fields where this approach can be applied is just the e-Learning. In this context the adaptive learning resources selection and sequencing is recognized as among one of the most interesting research questions. An Adaptive Educational Hypermedia System is composed by services for the management of the Knowledge Space, the definition of a User Model, the observation of student during his learning period and, as previously said, the adaptation of the learning path according to the real needs of the students. In particular the use of ontologyཿs formalism for the modeling of the ཿknowledge space࿝ related to the course can increase the sharable of learning objects among similar courses or better contextualize their role in the course. This paper addresses the design problem of an Adaptive hypermedia system by the definition of methodologies able to manage each its components, In particular an original user, learning contents, tracking strategies and adaptation model are developed. The proposed Adaptive Educational Hypermedia System has been integrated in an e-Learning platform and an experimental campaign has been conducted. In particular the proposed approach has been introduced in three different blended courses. A comparison with traditional approach has been described and the obtained results seem to be very promising.

  11. Adaptive genetic algorithm for path planning of loosely coordinated multi-robot manipulators

    Institute of Scientific and Technical Information of China (English)

    高胜; 赵杰; 蔡鹤皋

    2003-01-01

    Adaptive genetic algorithm ASAGA, a novel algorithm, which can dynamically modify the parameters of Genetic Algorithms in terms of simulated annealing mechanism, is proposed for path planning of loosely coordinated multi-robot manipulators. Over the task space of a multi-robot, a strategy of decoupled planning is also applied to the evolutionary process, which enables a multi-robot to avoid falling into deadlock and calculating of composite C-space. Finally, two representative tests are given to validate ASA GA and the strategy of decoupled planning.

  12. Adaptive scallop height tool path generation for robot-based incremental sheet metal forming

    Science.gov (United States)

    Seim, Patrick; Möllensiep, Dennis; Störkle, Denis Daniel; Thyssen, Lars; Kuhlenkötter, Bernd

    2016-10-01

    Incremental sheet metal forming is an emerging process for the production of individualized products or prototypes in low batch sizes and with short times to market. In these processes, the desired shape is produced by the incremental inward motion of the workpiece-independent forming tool in depth direction and its movement along the contour in lateral direction. Based on this shape production, the tool path generation is a key factor on e.g. the resulting geometric accuracy, the resulting surface quality, and the working time. This paper presents an innovative tool path generation based on a commercial milling CAM package considering the surface quality and working time. This approach offers the ability to define a specific scallop height as an indicator of the surface quality for specific faces of a component. Moreover, it decreases the required working time for the production of the entire component compared to the use of a commercial software package without this adaptive approach. Different forming experiments have been performed to verify the newly developed tool path generation. Mainly, this approach serves to solve the existing conflict of combining the working time and the surface quality within the process of incremental sheet metal forming.

  13. APF-guided adaptive immune network algorithm for robot path planning

    Institute of Scientific and Technical Information of China (English)

    Mingxin YUAN; Sunan WANG; Canyang WU; Kunpeng LI

    2009-01-01

    Inspired by the mechanism of Jerne's idiotypic network hypothesis, a new adaptive immune network algorithm (AINA) is presented through the stimulation and suppression between the antigen and antibody by taking the environment and robot behavior as antigen and antibody respectively. A guiding weight is defined based on the artificial potential field (APF) method, and the guiding weight is combined with antibody vitality to construct a new antibody selection operator, which improves the searching efficiency. In addition, an updating operator of antibody vi-tality is provided based on the Baldwin effect, which results in a positive feedback mechanism of search and accelerates the convergence of the immune network. The simulation and experimental results show that the proposed algorithm is characterized by high searching speed, good convergence performance and strong planning ability, which solves the path planning well in complicated environments.

  14. Transverse Pupil Shifts for Adaptive Optics Non-Common Path Calibration

    Science.gov (United States)

    Bloemhof, Eric E.

    2011-01-01

    A simple new way of obtaining absolute wavefront measurements with a laboratory Fizeau interferometer was recently devised. In that case, the observed wavefront map is the difference of two cavity surfaces, those of the mirror under test and of an unknown reference surface on the Fizeau s transmission flat. The absolute surface of each can be determined by applying standard wavefront reconstruction techniques to two grids of absolute surface height differences of the mirror under test, obtained from pairs of measurements made with slight transverse shifts in X and Y. Adaptive optics systems typically provide an actuated periscope between wavefront sensor (WFS) and commonmode optics, used for lateral registration of deformable mirror (DM) to WFS. This periscope permits independent adjustment of either pupil or focal spot incident on the WFS. It would be used to give the required lateral pupil motion between common and non-common segments, analogous to the lateral shifts of the two phase contributions in the lab Fizeau. The technique is based on a completely new approach to calibration of phase. It offers unusual flexibility with regard to the transverse spatial frequency scales probed, and will give results quite quickly, making use of no auxiliary equipment other than that built into the adaptive optics system. The new technique may be applied to provide novel calibration information about other optical systems in which the beam may be shifted transversely in a controlled way.

  15. An Adaptive Dynamic Surface Controller for Ultralow Altitude Airdrop Flight Path Angle with Actuator Input Nonlinearity

    Directory of Open Access Journals (Sweden)

    Mao-long Lv

    2016-01-01

    Full Text Available In the process of ultralow altitude airdrop, many factors such as actuator input dead-zone, backlash, uncertain external atmospheric disturbance, and model unknown nonlinearity affect the precision of trajectory tracking. In response, a robust adaptive neural network dynamic surface controller is developed. As a result, the aircraft longitudinal dynamics with actuator input nonlinearity is derived; the unknown nonlinear model functions are approximated by means of the RBF neural network. Also, an adaption strategy is used to achieve robustness against model uncertainties. Finally, it has been proved that all the signals in the closed-loop system are bounded and the tracking error converges to a small residual set asymptotically. Simulation results demonstrate the perfect tracking performance and strong robustness of the proposed method, which is not only applicable to the actuator with input dead-zone but also suitable for the backlash nonlinearity. At the same time, it can effectively overcome the effects of dead-zone and the atmospheric disturbance on the system and ensure the fast track of the desired flight path angle instruction, which overthrows the assumption that system functions must be known.

  16. Determining paths by which farmers can adapt effectively to scarce freshwater resources

    Science.gov (United States)

    Watson, R.; Hornberger, G.; Carrico, A. R.

    2012-12-01

    Stress on freshwater resources is a significant risk associated with climatic change. The risk is even greater given the expected changes in overall resource use as the developing world develops, as the world's population continues to grow, and as land use changes dramatically. Effective water management has implications for food security, health, and political stability worldwide. This is particularly true in developing regions heavily dependent on agriculture, and where agriculture depends on irrigation. Adaptation to water stress requires both managing water allocation among competing users and ensuring that each user is efficient in his or her use of a limited allotment: the problem is a quintessential common-pool resource (CPR) dilemma. In the future even more so than in the past, adaptation will be essential as the world evolves. The problem that we identify—determining paths by which farmers can adapt effectively to increasingly scarce freshwater resources—is one of great scientific and societal importance. The issue lies at the intersection of water-cycle processes and social-psychological processes that influence and are influenced by water availability and use. This intersection harbors intriguing unresolved scientific questions; advances in natural and social sciences will stem from attacks on the overall problem. The issue is societally compelling because the ability of the world to supply adequate food for a population expected to grow to over 9 billion by 2050 may well be determined by how farmers, consumers, and government institutions adapt to changing conditions of water availability. Major strides have been made in recent decades in understanding why Hardin's envisioned "tragedy of the commons" is avoided under certain circumstances, in some cases through self-organization rather than government intervention originally considered a necessity. Furthermore, we now know that the impacts of decisions about allocation and use of water can be

  17. Experimental evolution as an efficient tool to dissect adaptive paths to antibiotic resistance.

    Science.gov (United States)

    Jansen, Gunther; Barbosa, Camilo; Schulenburg, Hinrich

    2013-12-01

    Antibiotic treatments increasingly fail due to rapid dissemination of drug resistance. Comparative genomics of clinical isolates highlights the role of de novo adaptive mutations and horizontal gene transfer (HGT) in the acquisition of resistance. Yet it cannot fully describe the selective pressures and evolutionary trajectories that yielded today's problematic strains. Experimental evolution offers a compelling addition to such studies because the combination of replicated experiments under tightly controlled conditions with genomics of intermediate time points allows real-time reconstruction of evolutionary trajectories. Recent studies thus established causal links between antibiotic deployment therapies and the course and timing of mutations, the cost of resistance and the likelihood of compensating mutations. They particularly underscored the importance of long-term effects. Similar investigations incorporating horizontal gene transfer (HGT) are wanting, likely because of difficulties associated with its integration into experiments. In this review, we describe current advances in experimental evolution of antibiotic resistance and reflect on ways to incorporate horizontal gene transfer into the approach. We contend it provides a powerful tool for systematic and highly controlled dissection of evolutionary paths to antibiotic resistance that needs to be taken into account for the development of sustainable anti-bacterial treatment strategies.

  18. Path Integral Molecular Dynamics within the Grand Canonical-like Adaptive Resolution Technique: Quantum-Classical Simulation of Liquid Water

    CERN Document Server

    Agarwal, Animesh

    2015-01-01

    Quantum effects due to the spatial delocalization of light atoms are treated in molecular simulation via the path integral technique. Among several methods, Path Integral (PI) Molecular Dynamics (MD) is nowadays a powerful tool to investigate properties induced by spatial delocalization of atoms; however computationally this technique is very demanding. The abovementioned limitation implies the restriction of PIMD applications to relatively small systems and short time scales. One possible solution to overcome size and time limitation is to introduce PIMD algorithms into the Adaptive Resolution Simulation Scheme (AdResS). AdResS requires a relatively small region treated at path integral level and embeds it into a large molecular reservoir consisting of generic spherical coarse grained molecules. It was previously shown that the realization of the idea above, at a simple level, produced reasonable results for toy systems or simple/test systems like liquid parahydrogen. Encouraged by previous results, in this ...

  19. Active load path adaption in a simple kinematic load-bearing structure due to stiffness change in the structure's supports

    Science.gov (United States)

    Gehb, C. M.; Platz, R.; Melz, T.

    2016-09-01

    Load-bearing structures with kinematic functions enable and disable degrees of freedom and are part of many mechanical engineering applications. The relative movement between a wheel and the body of a car or a landing gear and an aircraft fuselage are examples for load-bearing systems with defined kinematics. In most cases, the load is transmitted through a predetermined load path to the structural support interfaces. However, unexpected load peaks or varying health condition of the system's supports, which means for example varying damping and stiffness characteristics, may require an active adjustment of the load path. However, load paths transmitted through damaged or weakened supports can be the reason for reduced comfort or even failure. In this paper a simplified 2D two mass oscillator with two supports is used to numerically investigate the potential of controlled adaptive auxiliary kinematic guidance elements in a load-bearing structure to adapt the load path depending on the stiffness change, representing damage of the supports. The aim is to provide additional forces in the auxiliary kinematic guidance elements for two reasons. On the one hand, one of the two supports that may become weaker through stiffness change will be relieved from higher loading. On the other hand, tilting due to different compliance in the supports will be minimized. Therefore, shifting load between the supports during operation could be an effective option.

  20. Giving presentations

    CERN Document Server

    Ellis, Mark

    1997-01-01

    This is part of a series of books, which gives training in key business communication skills. Emphasis is placed on building awareness of language appropriateness and fluency in typical business interactions. This new edition is in full colour.

  1. Free-end adaptive nudged elastic band method for locating transition states in minimum energy path calculation

    Science.gov (United States)

    Zhang, Jiayong; Zhang, Hongwu; Ye, Hongfei; Zheng, Yonggang

    2016-09-01

    A free-end adaptive nudged elastic band (FEA-NEB) method is presented for finding transition states on minimum energy paths, where the energy barrier is very narrow compared to the whole paths. The previously proposed free-end nudged elastic band method may suffer from convergence problems because of the kinks arising on the elastic band if the initial elastic band is far from the minimum energy path and weak springs are adopted. We analyze the origin of the formation of kinks and present an improved free-end algorithm to avoid the convergence problem. Moreover, by coupling the improved free-end algorithm and an adaptive strategy, we develop a FEA-NEB method to accurately locate the transition state with the elastic band cut off repeatedly and the density of images near the transition state increased. Several representative numerical examples, including the dislocation nucleation in a penta-twinned nanowire, the twin boundary migration under a shear stress, and the cross-slip of screw dislocation in face-centered cubic metals, are investigated by using the FEA-NEB method. Numerical results demonstrate both the stability and efficiency of the proposed method.

  2. Free-end adaptive nudged elastic band method for locating transition states in minimum energy path calculation.

    Science.gov (United States)

    Zhang, Jiayong; Zhang, Hongwu; Ye, Hongfei; Zheng, Yonggang

    2016-09-07

    A free-end adaptive nudged elastic band (FEA-NEB) method is presented for finding transition states on minimum energy paths, where the energy barrier is very narrow compared to the whole paths. The previously proposed free-end nudged elastic band method may suffer from convergence problems because of the kinks arising on the elastic band if the initial elastic band is far from the minimum energy path and weak springs are adopted. We analyze the origin of the formation of kinks and present an improved free-end algorithm to avoid the convergence problem. Moreover, by coupling the improved free-end algorithm and an adaptive strategy, we develop a FEA-NEB method to accurately locate the transition state with the elastic band cut off repeatedly and the density of images near the transition state increased. Several representative numerical examples, including the dislocation nucleation in a penta-twinned nanowire, the twin boundary migration under a shear stress, and the cross-slip of screw dislocation in face-centered cubic metals, are investigated by using the FEA-NEB method. Numerical results demonstrate both the stability and efficiency of the proposed method.

  3. Path integral molecular dynamics within the grand canonical-like adaptive resolution technique: Simulation of liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Animesh, E-mail: animesh@zedat.fu-berlin.de; Delle Site, Luigi, E-mail: dellesite@fu-berlin.de [Institute for Mathematics, Freie Universität Berlin, Berlin (Germany)

    2015-09-07

    Quantum effects due to the spatial delocalization of light atoms are treated in molecular simulation via the path integral technique. Among several methods, Path Integral (PI) Molecular Dynamics (MD) is nowadays a powerful tool to investigate properties induced by spatial delocalization of atoms; however, computationally this technique is very demanding. The above mentioned limitation implies the restriction of PIMD applications to relatively small systems and short time scales. One of the possible solutions to overcome size and time limitation is to introduce PIMD algorithms into the Adaptive Resolution Simulation Scheme (AdResS). AdResS requires a relatively small region treated at path integral level and embeds it into a large molecular reservoir consisting of generic spherical coarse grained molecules. It was previously shown that the realization of the idea above, at a simple level, produced reasonable results for toy systems or simple/test systems like liquid parahydrogen. Encouraged by previous results, in this paper, we show the simulation of liquid water at room conditions where AdResS, in its latest and more accurate Grand-Canonical-like version (GC-AdResS), is merged with two of the most relevant PIMD techniques available in the literature. The comparison of our results with those reported in the literature and/or with those obtained from full PIMD simulations shows a highly satisfactory agreement.

  4. Path integral molecular dynamics within the grand canonical-like adaptive resolution technique: Simulation of liquid water

    Science.gov (United States)

    Agarwal, Animesh; Delle Site, Luigi

    2015-09-01

    Quantum effects due to the spatial delocalization of light atoms are treated in molecular simulation via the path integral technique. Among several methods, Path Integral (PI) Molecular Dynamics (MD) is nowadays a powerful tool to investigate properties induced by spatial delocalization of atoms; however, computationally this technique is very demanding. The above mentioned limitation implies the restriction of PIMD applications to relatively small systems and short time scales. One of the possible solutions to overcome size and time limitation is to introduce PIMD algorithms into the Adaptive Resolution Simulation Scheme (AdResS). AdResS requires a relatively small region treated at path integral level and embeds it into a large molecular reservoir consisting of generic spherical coarse grained molecules. It was previously shown that the realization of the idea above, at a simple level, produced reasonable results for toy systems or simple/test systems like liquid parahydrogen. Encouraged by previous results, in this paper, we show the simulation of liquid water at room conditions where AdResS, in its latest and more accurate Grand-Canonical-like version (GC-AdResS), is merged with two of the most relevant PIMD techniques available in the literature. The comparison of our results with those reported in the literature and/or with those obtained from full PIMD simulations shows a highly satisfactory agreement.

  5. Adaptive Gait Control for a Quadruped Robot on 3D Path Planning

    Science.gov (United States)

    Igarashi, Hiroshi; Kakikura, Masayoshi

    A legged walking robot is able to not only move on irregular terrain but also change its posture. For example, the robot can pass under overhead obstacles by crouching. The purpose of our research is to realize efficient path planning with a quadruped robot. Therefore, the path planning is expected to extended in three dimensions because of the mobility. However, some issues of the quadruped robot, which are instability, workspace limitation, deadlock and slippage, complicate realizing such application. In order to improve these issues and reinforce the mobility, a new static gait pattern for a quadruped robot, called TFG: Trajectory Following Gait, is proposed. The TFG intends to obtain high controllability like a wheel robot. Additionally, the TFG allows to change it posture during the walk. In this paper, some experimental results show that the TFG improves the issues and it is available for efficient locomotion in three dimensional environment.

  6. Evolutionary engineering reveals divergent paths when yeast is adapted to different acidic environments

    DEFF Research Database (Denmark)

    Fletcher, Eugene; Feizi, Amir; Bisschops, Markus M. M.

    2017-01-01

    Tolerance of yeast to acid stress is important for many industrial processes including organic acid production. Therefore, elucidating the molecular basis of long term adaptation to acidic environments will be beneficial for engineering production strains to thrive under such harsh conditions....... Previous studies using gene expression analysis have suggested that both organic and inorganic acids display similar responses during short term exposure to acidic conditions. However, biological mechanisms that will lead to long term adaptation of yeast to acidic conditions remains unknown and whether...... sequencing and RNA-seq analysis of the evolved strains revealed different sets of genome alterations suggesting a divergence in adaptation to these two acids. An altered sterol composition and impaired iron uptake contributed to HCl tolerance whereas the formation of a multicellular morphology and rapid...

  7. Static and quasi-static behavior of an adaptive system to compensate path errors for smart fiber placement

    Science.gov (United States)

    Perner, M.; Monner, H. P.; Krombholz, C.; Kruse, F. F.

    2015-04-01

    Smart fiber placement is an ambitious topic in current research for automated manufacturing of large-scale composite structures, e.g. wing covers. Adaptive systems get in focus to obtain a high degree of observability and controllability of the manufacturing process. In particular, vibrational issues and material failure have to be studied to significantly increase the production rate with no loss in accuracy of the fiber layup. As one contribution, an adaptive system has been developed to be integrated into the fiber placement head. It decouples the compaction roller from disturbances caused by misalignments, varying components' behavior over a large work area and acceleration changes during operation. Therefore, the smart system axially adapts the position of the compaction roller in case of disturbances. This paper investigates the behavior of the system to compensate quasi-static deviations from the desired path. In particular, the compensation efficiency of a constant offset, a linear drift with constant gradient and a single-curved drift is studied. Thus, the test bed with measurement devices and scenarios is explained. Based on the knowledge obtained by the experimental data, the paper concludes with a discussion of the proposed approach for its use under operating conditions and further implementation.

  8. A Neural Path Integration Mechanism for Adaptive Vector Navigation in Autonomous Agents

    DEFF Research Database (Denmark)

    Goldschmidt, Dennis; Dasgupta, Sakyasingha; Wörgötter, Florentin

    2015-01-01

    to a simulated sixlegged artificial agent. Input signals from an allothetic compass and odometry are sustained through leaky neural integrator circuits, which are then used to compute the home vector by local excitation-global inhibition interactions. The home vector is computed and represented in circular...... arrays of neurons, where compass directions are population-coded and linear displacements are rate-coded. The mechanism allows for robust homing behavior in the presence of external sensory noise. The emergent behavior of the controlled agent does not only show a robust solution for the problem......Animals show remarkable capabilities in navigating their habitat in a fully autonomous and energy-efficient way. In many species, these capabilities rely on a process called path integration, which enables them to estimate their current location and to find their way back home after long...

  9. Progress in Adaptive Immunotherapy for Cancer in Companion Animals: Success on the Path to a Cure

    Directory of Open Access Journals (Sweden)

    Katie L. Anderson

    2015-10-01

    Full Text Available Harnessing the ability of the immune system to eradicate cancer has been a long-held goal of oncology. Work from the last two decades has finally brought immunotherapy into the forefront for cancer treatment, with demonstrable clinical success for aggressive tumors where other therapies had failed. In this review, we will discuss a range of therapies that are in different stages of clinical or preclinical development for companion animals with cancer, and which share the common objective of eliciting adaptive, anti-tumor immune responses. Even though challenges remain, manipulating the immune system holds significant promise to create durable responses and improve outcomes in companion animals with cancer. Furthermore, what we learn from this process will inform and accelerate development of comparable therapies for human cancer patients.

  10. Adaptive evolutionary paths from UV reception to sensing violet light by epistatic interactions

    Science.gov (United States)

    Yokoyama, Shozo; Altun, Ahmet; Jia, Huiyong; Yang, Hui; Koyama, Takashi; Faggionato, Davide; Liu, Yang; Starmer, William T.

    2015-01-01

    Ultraviolet (UV) reception is useful for such basic behaviors as mate choice, foraging, predator avoidance, communication, and navigation, whereas violet reception improves visual resolution and subtle contrast detection. UV and violet reception are mediated by the short wavelength–sensitive (SWS1) pigments that absorb light maximally (λmax) at ~360 nm and ~395 to 440 nm, respectively. Because of strong nonadditive (epistatic) interactions among amino acid changes in the pigments, the adaptive evolutionary mechanisms of these phenotypes are not well understood. Evolution of the violet pigment of the African clawed frog (Xenopus laevis, λmax = 423 nm) from the UV pigment in the amphibian ancestor (λmax = 359 nm) can be fully explained by eight mutations in transmembrane (TM) I–III segments. We show that epistatic interactions involving the remaining TM IV–VII segments provided evolutionary potential for the frog pigment to gradually achieve its violet-light reception by tuning its color sensitivity in small steps. Mutants in these segments also impair pigments that would cause drastic spectral shifts and thus eliminate them from viable evolutionary pathways. The overall effects of epistatic interactions involving TM IV–VII segments have disappeared at the last evolutionary step and thus are not detectable by studying present-day pigments. Therefore, characterizing the genotype-phenotype relationship during each evolutionary step is the key to uncover the true nature of epistasis. PMID:26601250

  11. Organised genome dynamics in the Escherichia coli species results in highly diverse adaptive paths.

    Directory of Open Access Journals (Sweden)

    Marie Touchon

    2009-01-01

    Full Text Available The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We uniformly (re- annotated the genomes of 20 commensal and pathogenic E. coli strains and one strain of E. fergusonii (the closest E. coli related species, including seven that we sequenced to completion. Within the approximately 18,000 families of orthologous genes, we found approximately 2,000 common to all strains. Although recombination rates are much higher than mutation rates, we show, both theoretically and using phylogenetic inference, that this does not obscure the phylogenetic signal, which places the B2 phylogenetic group and one group D strain at the basal position. Based on this phylogeny, we inferred past evolutionary events of gain and loss of genes, identifying functional classes under opposite selection pressures. We found an important adaptive role for metabolism diversification within group B2 and Shigella strains, but identified few or no extraintestinal virulence-specific genes, which could render difficult the development of a vaccine against extraintestinal infections. Genome flux in E. coli is confined to a small number of conserved positions in the chromosome, which most often are not associated with integrases or tRNA genes. Core genes flanking some of these regions show higher rates of recombination, suggesting that a gene, once acquired by a strain, spreads within the species by homologous recombination at the flanking genes. Finally, the genome's long-scale structure of recombination indicates lower recombination rates, but not higher mutation rates, at the terminus of replication. The ensuing effect of background selection and biased gene conversion may thus explain why this region is A+T-rich and shows high sequence divergence but low sequence polymorphism. Overall, despite a very high gene flow, genes co-exist in an

  12. Parametric 3D Atmospheric Reconstruction in Highly Variable Terrain with Recycled Monte Carlo Paths and an Adapted Bayesian Inference Engine

    Science.gov (United States)

    Langmore, Ian; Davis, Anthony B.; Bal, Guillaume; Marzouk, Youssef M.

    2012-01-01

    We describe a method for accelerating a 3D Monte Carlo forward radiative transfer model to the point where it can be used in a new kind of Bayesian retrieval framework. The remote sensing challenge is to detect and quantify a chemical effluent of a known absorbing gas produced by an industrial facility in a deep valley. The available data is a single low resolution noisy image of the scene in the near IR at an absorbing wavelength for the gas of interest. The detected sunlight has been multiply reflected by the variable terrain and/or scattered by an aerosol that is assumed partially known and partially unknown. We thus introduce a new class of remote sensing algorithms best described as "multi-pixel" techniques that call necessarily for a 3D radaitive transfer model (but demonstrated here in 2D); they can be added to conventional ones that exploit typically multi- or hyper-spectral data, sometimes with multi-angle capability, with or without information about polarization. The novel Bayesian inference methodology uses adaptively, with efficiency in mind, the fact that a Monte Carlo forward model has a known and controllable uncertainty depending on the number of sun-to-detector paths used.

  13. Unique Path Partitions

    DEFF Research Database (Denmark)

    Bessenrodt, Christine; Olsson, Jørn Børling; Sellers, James A.

    2013-01-01

    We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions.......We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions....

  14. Dynamic Adaptive RRT Path Planning Algorithm%动态自适应快速扩展树航迹规划算法研究

    Institute of Scientific and Technical Information of China (English)

    潘广贞; 秦帆; 张文斌

    2013-01-01

    快速扩展随机树(RRT)是航迹规划的重要算法,针对其难以直接应用于无人机航迹规划的问题,提出了动态自适应RRT算法.动态自适应RRT算法在随机点产生过程中加入无人机转弯角约束,使航迹更适合无人机直接跟踪;同时引入动态调节因子,根据环境中障碍密集程度调整规划步长,有效避免各类障碍.计算机实验结果表明动态自适应RRT算法在单航迹规划和多航迹规划中明显优于基本RRT算法和其它改进RRT算法,更适用于无人机航迹规划.%RRT is the important path planning algorithm. In view of its difficult to directly apply in UAVS path planning, this paper puts forwards the dynamic adaptive RRT algorithm. Adding turn corner constraints in the process of random point produce in order to make track for UAVS tracking more directly. At the same time, introduce dynamic adjustment factor, according to the environment of intensive degree to adjust the planning step length and avoid all kinds of barriers effectively. The computer experimental results show that the dynamic adaptive RRT algorithm in single path planning and more significantly than the basic path planning algorithm and other improvements RRT RRT algorithm, more applicable for UAVS path planning.

  15. Fundamental Evaluation of Adaptation and Human Capabilities in a Condition Using a System to Give a User an Artificial Oculomotor Function to Control Directions of Both Eyes Independently

    Directory of Open Access Journals (Sweden)

    Fumio Mizuno

    2011-10-01

    Full Text Available To investigate flexible adaptation of visual system, we developed a system to provide a user an artificial oculomotor function to control directions of both eyes. The system named “Virtual Chameleon” consists of two CCD cameras independently controlled and a head-mounted display. The user can control each tracking directions of two cameras with sensors set to both hands so that the user can get independent arbitrary view fields for both eyes. We performed fundamental experiments to evaluate capability to evaluate adaptation to use of Virtual Chameleon and effects on the user's capabilities. Eleven healthy volunteers with normal and corrected-to-normal vision participated in the experiments. The experiments were tests to find out each position of targets put in both side of a subject. In the experiments, a condition using Virtual Chameleon and a condition without it was adopted. We obtained accuracy rates and time intervals to find out target positions as experimental results. The experiments showed all of volunteers became able to actively control independent visual axes and correctly understood two different views by using Virtual Chameleon, even though two independent view fields yielded binocular rivalry to volunteers and binocular rivalry reduced human capabilities compared to cases without Virtual Chameleon.

  16. Design of a phased array for the generation of adaptive radiation force along a path surrounding a breast lesion for dynamic ultrasound elastography imaging.

    Science.gov (United States)

    Ekeom, Didace; Hadj Henni, Anis; Cloutier, Guy

    2013-03-01

    This work demonstrates, with numerical simulations, the potential of an octagonal probe for the generation of radiation forces in a set of points following a path surrounding a breast lesion in the context of dynamic ultrasound elastography imaging. Because of the in-going wave adaptive focusing strategy, the proposed method is adapted to induce shear wave fronts to interact optimally with complex lesions. Transducer elements were based on 1-3 piezocomposite material. Three-dimensional simulations combining the finite element method and boundary element method with periodic boundary conditions in the elevation direction were used to predict acoustic wave radiation in a targeted region of interest. The coupling factor of the piezocomposite material and the radiated power of the transducer were optimized. The transducer's electrical impedance was targeted to 50 Ω. The probe was simulated by assembling the designed transducer elements to build an octagonal phased-array with 256 elements on each edge (for a total of 2048 elements). The central frequency is 4.54 MHz; simulated transducer elements are able to deliver enough power and can generate the radiation force with a relatively low level of voltage excitation. Using dynamic transmitter beamforming techniques, the radiation force along a path and resulting acoustic pattern in the breast were simulated assuming a linear isotropic medium. Magnitude and orientation of the acoustic intensity (radiation force) at any point of a generation path could be controlled for the case of an example representing a heterogeneous medium with an embedded soft mechanical inclusion.

  17. 适应性学习路径推荐算法及应用研究%Recommendation Algorithm and Application of Adaptive Learning Path

    Institute of Scientific and Technical Information of China (English)

    赵呈领; 陈智慧; 黄志芳

    2015-01-01

    In the adaptive learning path recommendation, the recommendation algorithm plays a vital role. From the perspective of the nature of algorithm, the recommendation algorithm in learning path recommendation system are grouped into three categories:swarm intelligence optimization algorithm, data mining algorithms and knowledge-based recommendation algorithm. Combined with the developed recommendation system, the paper compared and analyzed from three aspects including performance of the algorithm, the parameter settings in the learning path recommendation and the application. the paper summarized the application strategies of relevant algorithm in the learning path recommendation, as well as the strengths and weaknesses in the application, and discussed the practical application value of learning path recommendation to provide valuable information and reference for research in the ifeld of adaptive learning path recommendation.%在适应性学习路径推荐中,推荐算法起着至关重要的作用。本研究从算法性质的角度归类,将学习路径推荐系统中的推荐算法归为三大类:智能优化算法、数据挖掘算法以及基于知识的推荐算法。结合已开发的学习路径推荐系统,本文从算法性能、学习路径推荐中考虑的因素及算法应用三方面进行比较与分析,总结出上述推荐算法在学习路径推荐中的应用策略和应用中的优势及不足,最后探讨了学习路径推荐的实践应用价值,以期为适应性学习路径推荐领域的研究提供有价值的参考与借鉴。

  18. Physarum Can Compute Shortest Paths

    CERN Document Server

    Bonifaci, Vincenzo; Varma, Girish

    2011-01-01

    A mathematical model has been proposed by biologists to describe the feedback mechanism used by the Physarum Polycephalum slime mold to adapt its tubular channels while foraging two food sources $s_0$ and $s_1$. We give a proof of the fact that, under this model, the mass of the mold will eventually converge to the shortest $s_0$-$s_1$ path of the network that the mold lies on, independently of the structure of the network or of the initial mass distribution. This matches the experimental observations by the biologists and can be seen as an example of a "natural algorithm", that is, an algorithm developed by evolution over millions of years.

  19. 变更路径预测支持的自适应模块建模%Adaptive Module Modeling by Predicting Change Path

    Institute of Scientific and Technical Information of China (English)

    乔虎; 莫蓉; 向颖

    2015-01-01

    针对现有模块变更方法变更路径单一、可扩展性较差等问题,提出构建自适应模块指导模块变更的方法。该方法引入图论,将模块中的参数表示为有向图的顶点,参数间的关系对应为有向图的边,建立邻接矩阵(设计结构矩阵)描述模块中各参数的关联性;通过设计结构矩阵聚类分析参数的关联关系,预测模块的可能变更路径;将变更路径与路径相关信息进行结构化存储,整合结构化信息与全约束模块实例,建立自适应模块;针对不同变更来源,提出自适应模块的变更方法。最后以运输车辆尾防护装置为例,验证了文中方法的可行性和合理性。%In order to solve the problems of single change path and extension difficulty in existing module change methods, an adaptive module modeling method is proposed. The graph theory is applied to develop an adjacency matrix (design structure matrix) to describe the relevance between different parameters. By analyzing clustered design structure matrix, module’s potential changing paths will be forecasted. The paper organized changing paths and related information into structured storage files to improve the extendibility of the changing paths and their related information. Then the structured information and fully constrained module are integrated to develop the self-adaption module. For the different changing sources, different self-regulation algorithms are proposed for the self-adaption module. Finally, the study verifies the feasibil-ity and rationality of the proposed method with an application case of truck bumper.

  20. 科技型中小企业适应性成长路径研究%Towards an adaptive growth path of medium and small technological enterprises

    Institute of Scientific and Technical Information of China (English)

    黄春萍; 刘奎颖; 曾珍香

    2011-01-01

    Medium and small technological enterprises are the main force of national economic development. Their healthy growth is the common concern of both the business and academic circles. The adaptation of these enterprises and their adaptive growth stages are analyzed and a model for their adaptive growth path is established. Finally, cluster analysis is applied in an empirical study.%科技型中小企业是国民经济发展的主力军,其健康成长是企业界和学术界共同关心的热点问题.本文首先分析了科技型中小企业的适应性及其适应性成长阶段,分别是创业阶段、发展阶段、成熟阶段和蜕变阶段;进而基于企业适应性这一视角,提出了科技型中小企业适应性成长路径为自主发展型、动态模仿型和创新涌现型,并构建了其适应性成长路径模型,最后应用聚类分析进行了实证研究.

  1. Giving Medication to Children

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Giving Medication to Children Share Tweet Linkedin Pin it More ... the upper limit. back to top Q: Are medications that are intended for children clinically tested on ...

  2. Path Dependency

    OpenAIRE

    Mark Setterfield

    2015-01-01

    Path dependency is defined, and three different specific concepts of path dependency – cumulative causation, lock in, and hysteresis – are analyzed. The relationships between path dependency and equilibrium, and path dependency and fundamental uncertainty are also discussed. Finally, a typology of dynamical systems is developed to clarify these relationships.

  3. The path to visible extreme adaptive optics with MagAO-2K and MagAO-X

    Science.gov (United States)

    Males, Jared R.; Close, Laird M.; Guyon, Olivier; Morzinski, Katie M.; Hinz, Philip; Esposito, Simone; Pinna, Enrico; Xompero, Marco; Briguglio, Runa; Riccardi, Armando; Puglisi, Alfio; Mazin, Ben; Ireland, Michael J.; Weinberger, Alycia; Conrad, Al; Kenworthy, Matthew; Snik, Frans; Otten, Gilles; Jovanovic, Nemanja; Lozi, Julien

    2016-07-01

    The next generation of extremely large telescopes (ELTs) have the potential to image habitable rocky planets, if suitably optimized. This will require the development of fast high order "extreme" adaptive optics systems for the ELTs. Located near the excellent site of the future GMT, the Magellan AO system (MagAO) is an ideal on-sky testbed for high contrast imaging development. Here we discuss planned upgrades to MagAO. These include improvements in WFS sampling (enabling correction of more modes) and an increase in speed to 2000 Hz, as well as an H2RG detector upgrade for the Clio infrared camera. This NSF funded project, MagAO-2K, is planned to be on-sky in November 2016 and will significantly improve the performance of MagAO at short wavelengths. Finally, we describe MagAO-X, a visible-wavelength extreme-AO "afterburner" system under development. MagAO-X will deliver Strehl ratios of over 80% in the optical and is optimized for visible light coronagraphy.

  4. Career Path Descriptions

    CERN Document Server

    Charkiewicz, A

    2000-01-01

    Before the Career Path system, jobs were classified according to grades with general statutory definitions, guided by the "Job Catalogue" which defined 6 evaluation criteria with example illustrations in the form of "typical" job descriptions. Career Paths were given concise statutory definitions necessitating a method of description and evaluation adapted to their new wider-band salary concept. Evaluations were derived from the same 6 criteria but the typical descriptions became unusable. In 1999, a sub-group of the Standing Concertation Committee proposed a new guide for describing Career Paths, adapted to their wider career concept by expanding the 6 evaluation criteria into 9. For each criterion several levels were established tracing the expected evolution of job level profiles and personal competencies over their longer salary ranges. While providing more transparency to supervisors and staff, the Guide's official use would be by services responsible for vacancy notices, Career Path evaluations and rela...

  5. Give blood at CERN

    CERN Multimedia

    SC Unit

    2008-01-01

    ACCIDENTS and ILLNESSES don’t take a break! DO SOMETHING AMAZING - GIVE BLOOD! IT’S IN ALL OUR INTERESTS. 30 July 2008 from 9.30 a.m. to 4 p.m. CERN RESTAURANT NOVAE First floor - Salle des Pas Perdus After you have given blood, you are invited to partake of refreshments kindly offered by NOVAE.

  6. Water equivalent path length calculations using scatter-corrected head and neck CBCT images to evaluate patients for adaptive proton therapy

    Science.gov (United States)

    Kim, Jihun; Park, Yang-Kyun; Sharp, Gregory; Busse, Paul; Winey, Brian

    2017-01-01

    Proton therapy has dosimetric advantages due to the well-defined range of the proton beam over photon radiotherapy. When the proton beams, however, are delivered to the patient in fractionated radiation treatment, the treatment outcome is affected by delivery uncertainties such as anatomic change in the patient and daily patient setup error. This study aims at establishing a method to evaluate the dosimetric impact of the anatomic change and patient setup error during head and neck proton therapy. Range variations due to the delivery uncertainties were assessed by calculating water equivalent path length (WEPL) to the distal edge of tumor volume using planning CT and weekly treatment cone-beam CT (CBCT) images. Specifically, mean difference and root mean squared deviation (RMSD) of the distal WEPLs were calculated as the weekly range variations. To accurately calculate the distal WEPLs, an existing CBCT scatter correction algorithm was used. An automatic rigid registration was used to align the planning CT and treatment CBCT images, simulating a six degree-of-freedom couch correction at treatments. The authors conclude that the dosimetric impact of the anatomic change and patient setup error was reasonably captured in the differences of the distal WEPL variation with a range calculation uncertainty of 2%. The proposed method to calculate the distal WEPL using the scatter-corrected CBCT images can be an essential tool to decide the necessity of re-planning in adaptive proton therapy.

  7. Death: 'nothing' gives insight.

    Science.gov (United States)

    Ettema, Eric J

    2013-08-01

    According to a widely accepted belief, we cannot know our own death--death means 'nothing' to us. At first sight, the meaning of 'nothing' just implies the negation or absence of 'something'. Death then simply refers to the negation or absence of life. As a consequence, however, death has no meaning of itself. This leads to an ontological paradox in which death is both acknowledged and denied: death is … nothing. In this article, I investigate whether insight into the ontological paradox of the nothingness of death can contribute to a good end-of-life. By analysing Aquinas', Heidegger's and Derrida's understanding of death as nothingness, I explore how giving meaning to death on different ontological levels connects to, and at the same time provides resistance against, the harsh reality of death. By doing so, I intend to demonstrate that insight into the nothingness of death can count as a framework for a meaningful dealing with death.

  8. Adaptive Path Planning of the UAV Based on Genetic Algorithm%基于遗传算法的UAV自适应航迹规划

    Institute of Scientific and Technical Information of China (English)

    王琪; 马璐; 邓会亨

    2013-01-01

      根据遗传算法与动态的稀疏A*搜索(Dynamic Sparse A* Search, DASA)算法各自的特点,提出一种组合优化算法来实现在不确定战场环境中自适应航迹规划。在无人机(UAV, Unmanned Aerial Vehicles)飞行前,采用全局搜索能力强的遗传算法进行全局搜索,对从起始点到目标点的飞行航线进行规划,生成全局最优或次优的可行参考飞行航线;在无人机任务执行阶段,以参考飞行航线为基准,采用 DASA 算法进行在线实时航迹再规划。仿真结果表明,与遗传算法相比,该组合算法不但能生成近似最优解,而且能够满足在线实时应用的要求。%According to the characteristics of genetic algorithm and the Dynamic Sparse A*Search (Dynamic Sparse A*Search, DASA) algorithm, this paper puts forward a combinational optimal algorithm fulfilling adaptive path planning in flying environment with unknown threat. Before flight, the ground station adopt genetic algorithm which possess the powerful ability of global search to realize Universal Search, we proceed programme from the starting point to the target point to generate the global optimal or suboptimal feasible reference airline. When the UAV is executing fly missions, DASA algorithm is used for on line route re planning based on the reference flight line as the benchmark. The simulation results show that compared with the genetic algorithm, the combined algorithm cannot only produce an approximate optimal solution, but also meet the requirements of real-time online application.

  9. Path Creation, Path Dependence and Breaking Away from the Path

    DEFF Research Database (Denmark)

    Wang, Jens Erik; Hedman, Jonas; Tuunainen, Virpi Kristiina

    2016-01-01

    The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop...... the importance of intermediate outcomes, which in the case of Nokia was the importance of software ecosystems and adaptable mobile devices. Furthermore, we show how the layers of path dependence mutually reinforce each other and become stronger....

  10. Path Sensitization

    Institute of Scientific and Technical Information of China (English)

    赵著行; 闵应骅; 等

    1997-01-01

    For different delay models,the concept of sensitization can be very different.Traditonal concepts of sensitization cannot precisely describe circuit behavior when the input vectors change very fast.Using Boolean process aporoach,this paper presents a new definition of sensitization for arbitrary input waveforms.By this new concept it is found that if the inputs of a combinational circuit can change at any time,and each gate's delay varies within an interval (bounded gate delay model),then every path,which is not necessarily a single topological path,is sensitizable.From the experimental results it can be seen that,all nonsensitizable paths for traditional concepts actually can propagate transitions along them for some input waveforms.However,specified time between input transitions(STBIT) and minimum permissible pulse width(ε)are two major factors to make some paths non-sensitizable.

  11. Path Integrals in Quantum Physics

    CERN Document Server

    Rosenfelder, R

    2012-01-01

    These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical evaluation of (euclidean) path integrals by Monte-Carlo methods with a program for the anharmonic oscillator. The second part deals with the application of path integrals in statistical mechanics and many-body problems treating the polaron problem, dissipative quantum systems, path integrals over ordinary and Grassmannian coherent states and perturbation theory for both bosons and fermions. Again a simple Fortran program is included for illustrating the use of strong-coupling methods. Finally, in the third part path integra...

  12. TADL-V2: An Improved Trust-Aware Dynamic Location-based Adaptation Protocol For Discovering Multiple Paths in MANETs

    Directory of Open Access Journals (Sweden)

    Helen Bakhsh

    2015-08-01

    Full Text Available Mobile ad hoc networks (MANETs have a number of features that make the provisioning of Quality of Services (QoS particularly challenging. One of the most challenging issues is how to discover more reliable paths for high priority traffic delivery in a highly mobile network and do so with minimum overhead costs. This paper attempts to address this issue by designing and evaluating a multi-path discovery protocol. This protocol, named as Trust-Aware Dynamic Location-based protocol version 2 (TADL-V2, is an improved version of our earlier published protocol, TADL. TADL-V2 has improved TADL in two aspects: (1 it uses a hybrid approach to node-disjoint path discovery based on the network mobility level and (2 it uses a mobility based approach to search area resizing. These measures enable TADL-V2 to discover more paths with reduced number of control packets injected into the network. Our simulation study shows that TADL-V2 outperforms TADL in terms of reducing control overheads when the network is highly mobile. This overhead reduction can have a positive effect on QoS provisioning.

  13. Path Dependence

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    Begrebet Path Dependence blev oprindelig udviklet inden for New Institutionel Economics af bl.a. David, Arthur og North. Begrebet har spredt sig vidt i samfundsvidenskaberne og undergået en udvikling. Dette paper propagerer for at der er sket så en så omfattende udvikling af begrebet, at man nu kan...... tale om 1. og 2. generation af Path Dependence begrebet. Den nyeste udvikling af begrebet har relevans for metodologi-diskusionerne i relation til Keynes...

  14. Path Integrals in Quantum Physics

    OpenAIRE

    2012-01-01

    These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical ev...

  15. K shortest paths in stochastic time-dependent networks

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Pretolani, Daniele; Andersen, Kim Allan

    2004-01-01

    , finding the a priori shortest path is NP-hard, while the best time-adaptive strategy can be found in polynomial time. In this paper, we propose a solution method for the a priori shortest path problem, and we show that it can be easily adapted to the ranking of the first K shortest paths. Moreover, we...

  16. Ranking shortest paths in Stochastic time-denpendent networks

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Andersen, Kim Allan; Pretolani, Daniele

    , finding the a priori shortest path is NP-hard, while the best time-adaptive strategy can be found in polynomial time. In this paper, we propose a solution method for the a priori shortest path problem, and we show that it can be easily adapted to the ranking of the first K shortest paths. Moreover, we...

  17. Path Creation

    DEFF Research Database (Denmark)

    Karnøe, Peter; Garud, Raghu

    2012-01-01

    This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts. Competenc......This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts....... Competencies emerged through processes and mechanisms such as co-creation that implicated multiple learning processes. The process was not an orderly linear one as emergent contingencies influenced the learning processes. An implication is that public policy to catalyse clusters cannot be based...

  18. Backstepping adaptive dynamical sliding mode control method for path following of underactuated surface vessel%欠驱动船路径跟踪的反演自适应动态滑模控制方法

    Institute of Scientific and Technical Information of China (English)

    廖煜雷; 万磊; 庄佳园

    2012-01-01

    针对欠驱动水面船的路径跟踪控制系统,提出一种反演自适应动态滑模控制方法.该系统由船舶艏摇非线性响应模型和Serret-Frenet误差动力学方程组成,并考虑建模误差和外界干扰力等不确定性.经过简化处理,将原欠驱动系统的控制问题转化为非线性系统的镇定问题.同时,基于反步方法和动态滑模控制理论,设计自适应动态滑模控制器.通过理论分析,证明在该控制器作用下,路径跟踪控制系统是全局渐近稳定的.仿真试验表明:该控制器对系统参数摄动和外界干扰不敏感,具有强鲁棒性和自适应性.%A method of backstepping adaptive dynamical sliding mode control (DSMC) was addressed for the path following control system of the underactuated surface vessel. The system consists of the nonlinear ship response model and the Serret-Frenet error dynamics equations. The control system takes account of the modeling errors and external disturbances. It transformed the original underactuated system into a nonlinear system via simplified analysis. An adaptive dynamical sliding mode controller was proposed based on backstepping method and dynamical sliding mode control theory. By means of theory analysis, it was proven that the proposed controller can render the path following control system globally asymptotically stable. Simulation results show that the controller is robust and adaptive to the systemic variations or disturbances.

  19. Adaptive, growth-oriented, and positive perceptions of mother-daughter elder caregiving relationships: a path-analytic investigation of predictors.

    Science.gov (United States)

    Hollis-Sawyer, L A

    2001-01-01

    One hundred twenty-two pairs (n = 244) of filial caregivers (daughters) and care recipients (mothers) were interviewed separately, to investigate the factors underlying positive, growth-oriented caregiving relationships. The outcome variable examined was the type of caregiving pair (positive, negative, mixed, and neutral), as determined by "blind" raters. Based on existing research, factors examined as being significant predictors of this outcome variable were perceived roles (role changes, role relations) and individual-difference characteristics (personality dimensions, fluid intellectual ability). The results of the path model tested support the importance of individual-difference factors in understanding positive mother-daughter elder caregiving relationships.

  20. Fitting In, without Giving In

    DEFF Research Database (Denmark)

    Nielsen, Rikke K.; Straub-Bauer, Andrea

    2014-01-01

    Adapting your leadership style to a different cultural setting can be tough, especially when the new setting demands a style different from how you would normally and comfortably behave at home. So how do you adapt your leadership behavior across cultures without losing yourself in the process?...

  1. Online Secondary Path Modeling Method for Adaptive Active Control of Structure Response%次级通道在线辨识的自适应结构响应主动控制研究

    Institute of Scientific and Technical Information of China (English)

    杜昕; 唐炜; 李强; 张辉

    2015-01-01

    Adaptive active control of structure response has been widely used in helicopter vibration control, because of good adaption, light weight, broad frequency band, efifcient and better control result. The identiifcation accuracy of secondary path, which denotes the transfer function from input of actuator to output of objective vibration reduction, has a signiifcant impact on system stability. Online secondary path modeling has the superiority which can track the change of lfight status including height, speed, environment, temperature and pressure. Comparison of the simulation results ilustrateed the advantages and disadvantages of three online secondary path modeling methods. Analyzed the adaptive iflter algorithm from the anti-interference and convergence point of view, and provided reference for helicopter vibration active control algorithm.%直升机结构响应自适应主动控制算法因其适应能力强、重量轻、频带范围宽,效率高且控制效果好在直升机振动抑制中得到广泛应用。从作动器控制输入到目标减振点响应输出之间的次级通道传递函数的辨识精度严重影响系统稳定性,在线辨识能够适应直升机飞行高度、速度、环境、温度及压力等的改变给次级通道带来的影响。通过3种次级通道在线辨识算法控制效果仿真对比,从抗干扰性和收敛速度的角度,分析了现有自适应滤波算法,为直升机减振主动控制算法的设计提供参考。

  2. The Limits to Giving Back

    Directory of Open Access Journals (Sweden)

    Jade S. Sasser

    2014-07-01

    Full Text Available In this thematic section, authors consider the limitations on giving back that they faced in field research, or saw others face. For some authors, their attempts at giving back were severely limited by the scope of their projects, or their understandings of local cultures or histories. For others, very specific circumstances and historical interventions of foreigners in certain places can limit how and to what extent a researcher is able to have a reciprocal relationship with the participating community. Some authors, by virtue of their lesser positions of power relative to those that they were studying, simply decided not to give back to those communities. In each article it becomes apparent that how and in what ways people give back is unique (and limited both to their personal values and the contexts in which they do research.

  3. Lexicographic Path Induction

    DEFF Research Database (Denmark)

    Schürmann, Carsten; Sarnat, Jeffrey

    2009-01-01

    Programming languages theory is full of problems that reduce to proving the consistency of a logic, such as the normalization of typed lambda-calculi, the decidability of equality in type theory, equivalence testing of traces in security, etc. Although the principle of transfinite induction...... an induction principle that combines the comfort of structural induction with the expressive strength of transfinite induction. Using lexicographic path induction, we give a consistency proof of Martin-Löf’s intuitionistic theory of inductive definitions. The consistency of Heyting arithmetic follows directly...

  4. Green infrastructure as a climate change adaptation policy intervention: muddying the waters or clearing a path to a more secure future?

    Science.gov (United States)

    Sussams, L W; Sheate, W R; Eales, R P

    2015-01-01

    As dangerous climate change looms, decision-makers are increasingly realising that societies will need to adapt to this threat as well as mitigate against it. Green infrastructure (GI) is increasingly seen as an ideal climate change adaptation policy response. However, with this research the authors identify a number of crucial knowledge gaps within GI and, consequently, call for caution and for a concerted effort to understand the concept and what it can really deliver. GI has risen to prominence in a range of policy areas in large part due to its perceived ability to produce multiple benefits simultaneously, termed 'multifunctionality'. This characteristic strengthens the political appeal of the policy in question at a time when environmental issues have slipped down political agendas. Multifunctionality, however, brings its own set of new challenges that should be evaluated fully before the policy is implemented. This research takes important first steps to developing a critical understanding of what is achievable within GI's capacity. It focuses on one of GI's single objectives, namely climate change adaptation, to focus the analysis of how current obstacles in applying GI's multifunctionality could lead to the ineffective delivery of its objective. By drawing on expert opinion from government officials and representatives from the private, non-government organisation (NGO) and academic sectors, this research questions GI's ability to be effectively 'multifunctional' with an inconsistent definition at its core, deficiencies in its understanding and conflicts within its governance. In light of these observations, the authors then reflect on the judiciousness of applying GI to achieve the other objectives it has also been charged with delivering.

  5. Path Minima Queries in Dynamic Weighted Trees

    DEFF Research Database (Denmark)

    Davoodi, Pooya; Brodal, Gerth Stølting; Satti, Srinivasa Rao

    2011-01-01

    In the path minima problem on a tree, each edge is assigned a weight and a query asks for the edge with minimum weight on a path between two nodes. For the dynamic version of the problem, where the edge weights can be updated, we give data structures that achieve optimal query time\\todo{what about...

  6. UAV Path Planning Based on Adaptive Genetic Algorithm%基于自适应遗传算法的无人机航迹规划方法研究

    Institute of Scientific and Technical Information of China (English)

    徐正军; 唐硕

    2008-01-01

    With the development of the warfare, it becomes more and more difficult for the military aircraft to attack the target. Path planning is one of the available methods to increase the survival probability. In recent years, genetic algorithm (GA) has been successfully applied to path planning problems for unmanned aerial vehicle (UAV) systems, including single- and multi-vehicle systems. A new encoding method was designed by using bilinear-chain node and the mutation operator with combined operator with reconstruction operator and disturbance operator was improved. An adaptive genetic algorithm (ADGA), which determined the optimal path between the nodes with respect to a set of cost factors and constraints, was applied to the optimal path planning. Example simulation shows that the new algorithm satisfies the requirements in the computation efficiency and the precision of the solution. The algorithm is easy to be realized. Its practicability is improved.%随着攻防系统的发展与完善,实现飞行器有效突防越来越困难,而采用航迹规划技术能够有效的提高飞行器的突防概率.基于此,首先研究了参考航迹的角度、高度以及航迹段长度等约束条件;其次对航迹编码方式进行了改进,采用全实数的双向链表的编码方式;对自适应遗传算法的交叉和变异概率的计算方法、交叉算子和变异算子进行了改进,并应用该算法在求解航迹规划问题上进行了仿真研究,对采用不同的变异算子所得结果进行了对比分析.仿真计算的结果表明,该算法能够规划出一条满足要求的参考航迹,采用组合变异算子能取得比采用单个变异算子更优的参考航迹.

  7. Giving Psychology Away Is Expensive

    Science.gov (United States)

    Gorsuch, Richard L.; Wallace, William L.

    2005-01-01

    This article presents comments on "Does Psychology make a significant difference in our lives?" by P. Zimbardo. We deeply appreciate the documentation and inspiration provided by Zimbardo on how psychology is reaching out to the public by "giving psychology away" (p. 340). We totally agree that psychology has much, much more to offer that could be…

  8. The Shortest Path with Intelligent Algorithm

    Directory of Open Access Journals (Sweden)

    Surachai Panich

    2010-01-01

    Full Text Available Problem statement: Path planning algorithms need to be developed and implemented in a suitable manner to give better understanding about the intelligent system and also stimulates technological supply to enormous demands in an intelligent vehicle industry. Approach: This study concerned with intelligent path planning using A* search algorithm. Results: This study introduced intelligent path planning with A* search algorithm, which use to generate the most efficient path to goal. The algorithm was tested on simulator. Conclusion: This study is an implementation of a path planning for an intelligent path planning. The implementations are tested and verified with the simulation software. The path planning algorithms were selected for the implementation and to verify them.

  9. Paths of algebraic hyperbolic curves

    Institute of Scientific and Technical Information of China (English)

    Ya-juan LI; Li-zheng LU; Guo-zhao WANG

    2008-01-01

    Cubic algebraic hyperbolic (AH) Bezier curves and AH spline curves are defined with a positive parameter α in the space spanned by {1, t, sinht, cosht}. Modifying the value of α yields a family of AH Bezier or spline curves with the family parameter α. For a fixed point on the original curve, it will move on a defined curve called "path of AH curve" (AH Bezier and AH spline curves) when α changes. We describe the geometric effects of the paths and give a method to specify a curve passing through a given point.

  10. Resurrection plants of the genus Ramonda: prospective survival strategies – unlock further capacity of adaptation, or embark on the path of evolution?

    Directory of Open Access Journals (Sweden)

    Tamara eRakic

    2014-01-01

    Full Text Available Paleoendemic species of the monophyletic genus Ramonda (R. myconi, R. serbica and R. nathaliae are the remnants of the Tertiary tropical and subtropical flora in Europe. They are the rare resurrection plants of Northern Hemisphere temperate zone. Ramonda serbica and R. nathaliae are chorologically differentiated in the Balkan Peninsula and occupy similar habitats in calcareous, northward slopes in canyons and mountainsides. They remain well-hydrated during spring, late autumn and even in winter. In summer and early autumn when plants are subjected to drought and thermal stress, their desiccation tolerance comes into operation and they fall into anabiosis. Investigations revealed the permanent presence of ubiquitine and its conjugates, high amounts of oxalic acid and proline. Both species are homoiochlorophyllous. It enables them to rapidly resume photosynthesis upon rehydration, but also makes them susceptible to ROS formation. Dehydration induces activation of antioxidative enzymes (APX, GR, PPO, increase in amounts of AsA and GSH, phenolic acids, dehydrins, sucrose and inorganic ions. Plasma membranes, characterized by high amount of cholesterol, are subjected to decrease in membrane fluidity mostly on account of increased level of lipid saturation.Cytogenetic analysis revealed that R. nathaliae is a diploid (2n=48 and probably evolutionary older species, while R. serbica is a hexaploid (2n=144. Two species live together in only two localities forming hybrid individuals (2n=96. Polyploidization is the major evolutionary mechanism in the genus Ramonda that together with hybridization ability indicates that these relict species which have preserved an ancient survival strategy are not the evolutionary „dead end.The species of the genus Ramonda are promising sources of data important for understanding the complex strategy of resurrection plants’ survival, appraised through a prism of their evolutionary and adaptive potential for multiple

  11. Giving them a second chance

    Energy Technology Data Exchange (ETDEWEB)

    Mohn, L.

    Manaties are finding a haven in the warm water discharges from Florida power plants. They and other endangered species are the subject of a short film, A Second Chance, which tells the story of the efforts electric utilities are making to give wildlife another chance. The movie shows 15 programs of participating utilities to identify and promote activities with a positive environmental impact on bald eagles, crocodiles, bighorn sheep, and other threatened species. The film is available in print or broadcast tape form. (DCK)

  12. 'Lean' approach gives greater efficiency.

    Science.gov (United States)

    Call, Roger

    2014-02-01

    Adapting the 'Lean' methodologies used for many years by many manufacturers on the production line - such as in the automotive industry - and deploying them in healthcare 'spaces' can, Roger Call, an architect at Herman Miller Healthcare in the US, argues, 'easily remedy many of the inefficiencies' found within a healthcare facility. In an article that first appeared in the September 2013 issue of The Australian Hospital Engineer, he explains how 'Lean' approaches such as the 'Toyota production system', and 'Six Sigma', can be harnessed to good effect in the healthcare sphere.

  13. 基于随机网络编码的WSN多径传输自适应节能算法%An energy-saving multi-path adaptive algorithm based on random network coding in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    孙玲芳; 候志鲁; 许锋; 周家波

    2016-01-01

    The paper proposes an energy-saving multi-path adaptive algorithm based on random network coding in wireless sensor networks (RNC-ESMP). First of all, This algorithm considers the nodesˊenergy, let the data packets transmitted on the paths which have least energy consumption during data transferring. Second, considering the decoding probability of the sink nodes as the feedback factor, the algorithm builds a feedback mechanism from the sink nodes to the source nodes to make self-adaptive impossible. Then the algorithm proposes the encoding options and probability of the intermediate nodes so as to reduce the complexity of encoding. At last, it builds the platform on MATLAB to simulate the algorithm. The results of the experiment shows that this algorithm not only can reduce the average energy consumption of networks efficiently but also can extend the networksˊlife-time.%提出一种多路径的无线传感器网络(WSN)自适应节能算法,该算法的实现基于随机网络编码(RNC-ESMP)。其基本思想是:首先,该算法以WSN节点能量为考量,将数据经由节点能量最多的路径传输;其次,以目的节点解码成功率为反馈因子,构建目的节点到源节点的反馈机制,实现自适应;再次,选择合适的编码策略对数据包进行编码。最后在MATLAB环境下搭建仿真平台进行模拟仿真。实验结果表明,相比于传统的多路径算法,RNC-ESMP算法能够有效降低网络平均能耗,延长网络生命周期。

  14. Anomalous paths in quantum mechanical path-integrals

    Energy Technology Data Exchange (ETDEWEB)

    Grimsmo, Arne L., E-mail: arne.grimsmo@ntnu.no [Department of Physics, The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Department of Physics, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Klauder, John R., E-mail: klauder@phys.ufl.edu [Departments of Physics and Mathematics, University of Florida, Gainesville, FL 32611 (United States); Skagerstam, Bo-Sture K., E-mail: bo-sture.skagerstam@ntnu.no [Department of Physics, The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Kavli Institute for Theoretical Physics, Kohn Hall, University of California at Santa Barbara, CA 93106-4030 (United States); CREOL, The College of Optics and Photonics at the University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States)

    2013-11-25

    We investigate modifications of the discrete-time lattice action, for a quantum mechanical particle in one spatial dimension, that vanish in the naïve continuum limit but which, nevertheless, induce non-trivial effects due to quantum fluctuations. These effects are seen to modify the geometry of the paths contributing to the path-integral describing the time evolution of the particle, which we investigate through numerical simulations. In particular, we demonstrate the existence of a modified lattice action resulting in paths with any fractal dimension, d{sub f}, between one and two. We argue that d{sub f}=2 is a critical value, and we exhibit a type of lattice modification where the fluctuations in the position of the particle becomes independent of the time step, in which case the paths are interpreted as superdiffusive Lévy flights. We also consider the jaggedness of the paths, and show that this gives an independent classification of lattice theories.

  15. Robot path planning in dynamic environment based on reinforcement learning

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Proposes an adaptive learning method based on reinforcement learning for robot path planning prob lem, which enables the robot to adaptively learn and perform effective path planning, to avoid the moving obsta cles and reach the target. Thereby achieving automatic construction of path planning strategy and making the system adaptive to multi-robots system dynamic environments, and concludes from computer simulation experi ment that the method is powerful to solve the problem of multi-robot path planning, and it is a meaningful try to apply reinforcement learning techniques in multi-robot systems to develop the system's intelligence degree.

  16. Inversion of signature for paths of bounded variation

    CERN Document Server

    Lyons, Terry

    2011-01-01

    We develop two methods to reconstruct a path of bounded variation from its signature. The first method gives a simple and explicit expression of any axis path in terms of its signature, but it does not apply directlty to more general ones. The second method, based on an approximation scheme, recovers any tree-reduced path from its signature as the limit of a uniformly convergent sequence of lattice paths.

  17. 角色适应及职业紧张对护士组织氛围影响路径分析%Path analysis on the effect of role adaptation and job stress to nurses'organizational climate

    Institute of Scientific and Technical Information of China (English)

    罗艺; 曹小萍; 孟润堂; 刘冰

    2014-01-01

    目的:探讨护士角色适应、职业紧张对组织氛围的影响及其相互作用。方法采用多阶段抽样法抽取湖北省十堰市579名护理人员,采用医院组织气氛量表、职业紧张简洁量表和护士角色适应量表进行问卷调查。采用SPSS 18.0统计软件进行Spearman相关分析和路径分析。结果护士组织氛围处于中等偏上水平,职业紧张处于中等水平,角色适应处于中等偏下水平。职业紧张的工作控制维度和工作支持维度呈正相关[ Spearman相关系数(rS)=0.514, P<0.01]。角色适应的工作与家人维度和护理者与医院职工维度呈正相关(rS =0.327,P<0.01),和工作与本我维度呈正相关(rS=0.419, P<0.01)。角色适应、工作控制维度和工作支持维度对组织氛围的标准回归系数分别为0.386、-0.232、-0.411(P<0.01)。工作需求、工作控制和工作支持3个维度对角色适应的标准回归系数分别为-0.377、-0.126、-0.289(P<0.01)。职业紧张3个维度均直接反向影响角色适应,角色适应直接正向作用于组织氛围,职业紧张的工作需求维度可通过角色适应间接作用于组织氛围。结论职业紧张反向影响角色适应,角色适应正向作用于组织氛围,职业紧张的工作需求维度在角色适应与组织氛围之间起中介作用。%Objective To explore the effect of nursing role adaptation , occupational stress on organizational climate and its interaction.Methods Five hundred and seventy-nine nurses participated in the study according to multi-stage stratified sampling and the questionnaires of Organizational Climate Questionnaire , Brief Job Stress Questionnaire and Role Adapta-tion Questionnaire .Spearman correlation analysis and Path analysis were performed by SPSS 18.0 statistical software . Results The score of nurses ’ organizational climate was higher than the average level

  18. To Give or Not to Give, That Is the Question : How Methodology Is Destiny in Dutch Giving Data

    NARCIS (Netherlands)

    Bekkers, René; Wiepking, Pamala

    2006-01-01

    In research on giving, methodology is destiny. The volume of donations estimated from sample surveys strongly depends on the length of the questionnaire used to measure giving. By comparing two giving surveys from the Netherlands, the authors show that a short questionnaire on giving not only undere

  19. Quantum Adiabatic Evolution Algorithms with Different Paths

    CERN Document Server

    Farhi, E; Gutmann, S; Farhi, Edward; Goldstone, Jeffrey; Gutmann, Sam

    2002-01-01

    In quantum adiabatic evolution algorithms, the quantum computer follows the ground state of a slowly varying Hamiltonian. The ground state of the initial Hamiltonian is easy to construct; the ground state of the final Hamiltonian encodes the solution of the computational problem. These algorithms have generally been studied in the case where the "straight line" path from initial to final Hamiltonian is taken. But there is no reason not to try paths involving terms that are not linear combinations of the initial and final Hamiltonians. We give several proposals for randomly generating new paths. Using one of these proposals, we convert an algorithmic failure into a success.

  20. Method of Optical Grooming for Distance-adaptive and Effective Sharing Path-aware%基于距离自适应和有效共享路径感知的光疏导方法

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    针对灵活网格光网络中如何节约转发器与频谱资源的问题,该文研究了多点到多点组播业务的光路环路由机制,提出一种基于距离自适应和有效共享路径感知的光疏导方法。通过设计一种基于距离自适应的预处理机制,该疏导方法能根据业务成员节点的分布特点和距离自适应准则灵活地为业务构建光路环;在路由与频谱分配阶段,该疏导方法通过构造一个面向光疏导的业务决策矩阵和一个优先调度向量,将业务疏导到与当前业务具有有效共享路径最多的已路由业务上,并优先分配所需的频谱空间以提高光疏导的成功率,实现节约转发器与频谱资源的目的。仿真结果表明,该文提出的光疏导方法可以有效地减少业务消耗的转发器数目和子载波数目。%In order to address the problem of reducing the resources of transponder and spectrum in flexible grid optical networks, a lightpath circle mechanism is studied for many-to-many multicast requests, and a method of optical grooming is proposed based on distance-adaptive and effective sharing path-aware. By designing a strategy of traffic pre-processing based on distance-adaptive, a lightpath circle is constructed according to the distribution characteristics of member nodes and the distance-adaptive criterion in the proposed method. In the process of routing and spectrum allocation, by constructing a decision matrix oriented optical grooming and a priority scheduling vector, the multicast request is groomed into the established traffic with the highest effective sharing links. Moreover, the appropriate spectrum resources are allocated for the groomed requests to increase the success rates of grooming and to save the resources of transponder and spectrum. Simulation results show that the proposed method can significantly reduce the number of traffic consumed transponders and sub-carriers.

  1. Collaborative path planning for a robotic wheelchair.

    Science.gov (United States)

    Zeng, Qiang; Teo, Chee Leong; Rebsamen, Brice; Burdet, Etienne

    2008-11-01

    Generating a path to guide a wheelchair's motion faces two challenges. First, the path is located in the human environment and that is usually unstructured and dynamic. Thus, it is difficult to generate a reliable map and plan paths on it by artificial intelligence. Second, the wheelchair, whose task is to carry a human user, should move on a smooth and comfortable path adapted to the user's intentions. To meet these challenges, we propose that the human operator and the robot interact to create and gradually improve a guide path. This paper introduces design tools to enable an intuitive interaction, and reports experiments performed with healthy subjects in order to investigate this collaborative path learning strategy. We analyzed features of the optimal paths and user evaluation in representative conditions. This was complemented by a questionnaire filled out by the subjects after the experiments. The results demonstrate the effectiveness of this approach, and show the utility and complementarity of the tools to design ergonomic guide paths.

  2. Mapping the imaginary of charitable giving

    DEFF Research Database (Denmark)

    Bajde, Domen

    2012-01-01

    The meaningfulness of charitable giving is largely owed to the imaginary conceptions that underpin this form of giving. Building on Taylor's notion of “social imaginary” and Godelier's work on “gift imaginary,” we theorize the imaginary of charitable giving. Through a combination of qualitative m...... across relatively stable assemblages of conceptions of poverty, donors, end-recipients and charitable giving. These assemblages are suggested to form a multifaceted imaginary that is both cultural (shared) and personal (individually performed)....

  3. Income Tax Policy and Charitable Giving

    Science.gov (United States)

    Brooks, Arthur C.

    2007-01-01

    Many studies over the past 20 years have looked at the response of charitable donations to tax incentives--the tax price elasticity of giving. Generally, authors have assumed this elasticity is constant across all types of giving. Using the 2001 Panel Study of Income Dynamics data on charitable giving, this paper estimates the tax price elasticity…

  4. Predictors of Retirement Satisfaction: A Path Model.

    Science.gov (United States)

    Kremer, Yael

    1985-01-01

    Examined adjustment to retirement among 310 former industrial and service workers. Respondents had come to terms with retirement and enjoyed their more relaxed lifestyle. Dominant variables in the path model were retirees' satisfaction with specific aspects of retirement: giving up work, activities with family and friends, rest, and free time. (BH)

  5. The Practical Realities of Giving Back

    Directory of Open Access Journals (Sweden)

    Ashton Bree Wesner

    2014-07-01

    Full Text Available In this thematic section, authors consider practical ways of giving back to the communities in which they conduct research. Each author discusses their evolving thoughts on how to give back in these practical ways. Some of these authors discuss giving back by giving money, food, rides, parties, and water bottles. In other cases, authors discuss giving back by creating jobs in the short or long term, grant writing, advocacy, and education. Story-telling is also a theme that many of the authors in this section discuss. For some authors, non-material forms of giving back are critical—simply maintaining social ties to the communities in which they worked, or sharing humor. The authors consider the utility of their attempts at giving back, and in some cases present their personal philosophy or guidelines on the subject.

  6. Path ideals of rooted trees and their graded Betti numbers

    CERN Document Server

    Bouchat, Rachelle R; O'Keefe, Augustine

    2010-01-01

    Let $\\Gamma$ be a rooted tree and let $t$ be a positive integer. We study algebraic invariants and properties of the path ideal generated by monomial corresponding to paths of length $(t-1)$ in $\\Gamma$. In particular, we give a recursive formula to compute the graded Betti numbers, a general bound for the regularity, an explicit computation of the linear strand, and we characterize when this path ideal has a linear resolution.

  7. Transition Path Theory

    Science.gov (United States)

    vanden-Eijnden, E.

    The dynamical behavior of many systems arising in physics, chemistry, biology, etc. is dominated by rare but important transition events between long lived states. For over 70 years, transition state theory (TST) has provided the main theoretical framework for the description of these events [17,33,34]. Yet, while TST and evolutions thereof based on the reactive flux formalism [1, 5] (see also [30,31]) give an accurate estimate of the transition rate of a reaction, at least in principle, the theory tells very little in terms of the mechanism of this reaction. Recent advances, such as transition path sampling (TPS) of Bolhuis, Chandler, Dellago, and Geissler [3, 7] or the action method of Elber [15, 16], may seem to go beyond TST in that respect: these techniques allow indeed to sample the ensemble of reactive trajectories, i.e. the trajectories by which the reaction occurs. And yet, the reactive trajectories may again be rather uninformative about the mechanism of the reaction. This may sound paradoxical at first: what more than actual reactive trajectories could one need to understand a reaction? The problem, however, is that the reactive trajectories by themselves give only a very indirect information about the statistical properties of these trajectories. This is similar to why statistical mechanics is not simply a footnote in books about classical mechanics. What is the probability density that a trajectory be at a given location in state-space conditional on it being reactive? What is the probability current of these reactive trajectories? What is their rate of appearance? These are the questions of interest and they are not easy to answer directly from the ensemble of reactive trajectories. The right framework to tackle these questions also goes beyond standard equilibrium statistical mechanics because of the nontrivial bias that the very definition of the reactive trajectories imply - they must be involved in a reaction. The aim of this chapter is to

  8. Path Integrals and Hamiltonians

    Science.gov (United States)

    Baaquie, Belal E.

    2014-03-01

    1. Synopsis; Part I. Fundamental Principles: 2. The mathematical structure of quantum mechanics; 3. Operators; 4. The Feynman path integral; 5. Hamiltonian mechanics; 6. Path integral quantization; Part II. Stochastic Processes: 7. Stochastic systems; Part III. Discrete Degrees of Freedom: 8. Ising model; 9. Ising model: magnetic field; 10. Fermions; Part IV. Quadratic Path Integrals: 11. Simple harmonic oscillators; 12. Gaussian path integrals; Part V. Action with Acceleration: 13. Acceleration Lagrangian; 14. Pseudo-Hermitian Euclidean Hamiltonian; 15. Non-Hermitian Hamiltonian: Jordan blocks; 16. The quartic potential: instantons; 17. Compact degrees of freedom; Index.

  9. Path Problems in Networks

    CERN Document Server

    Baras, John

    2010-01-01

    The algebraic path problem is a generalization of the shortest path problem in graphs. Various instances of this abstract problem have appeared in the literature, and similar solutions have been independently discovered and rediscovered. The repeated appearance of a problem is evidence of its relevance. This book aims to help current and future researchers add this powerful tool to their arsenal, so that they can easily identify and use it in their own work. Path problems in networks can be conceptually divided into two parts: A distillation of the extensive theory behind the algebraic path pr

  10. Multi-Dimensional Path Queries

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    1998-01-01

    We present the path-relationship model that supports multi-dimensional data modeling and querying. A path-relationship database is composed of sets of paths and sets of relationships. A path is a sequence of related elements (atoms, paths, and sets of paths). A relationship is a binary path...... to create nested path structures. We present an SQL-like query language that is based on path expressions and we show how to use it to express multi-dimensional path queries that are suited for advanced data analysis in decision support environments like data warehousing environments...

  11. Path dependence and creation

    DEFF Research Database (Denmark)

    Garud, Raghu; Karnøe, Peter

    the place of agency in these theories that take history so seriously. In the end, they are as interested in path creation and destruction as they are in path dependence. This book is compiled of both theoretical and empirical writing. It shows relatively well-known industries such as the automobile...

  12. Free path groupoid grading on Leavitt path algebras

    OpenAIRE

    Goncalves, Daniel; Yoneda, Gabriela

    2015-01-01

    In this work we realize Leavitt path algebras as partial skew groupoid rings. This yields a free path groupoid grading on Leavitt path algebras. Using this grading we characterize free path groupoid graded isomorphisms of Leavitt path algebras that preserves generators.

  13. *-Regular Leavitt Path Algebras of Arbitrary Graphs

    Institute of Scientific and Technical Information of China (English)

    Gonzalo ARANDA PINO; Kulumani RANGASWAMY; Lia VA(S)

    2012-01-01

    If K is a field with involution and E an arbitrary graph,the involution from K naturally induces an involution of the Leavitt path algebra LK(E).We show that the involution on LK(E) is proper if the involution on K is positive-definite,even in the case when the graph E is not necessarily finite or row-finite.It has been shown that the Leavitt path algebra LK(E) is regular if and only if E is acyclic.We give necessary and sufficient conditions for LK(E) to be *-regular (i.e.,regular with proper involution).This characterization of *-regularity of a Leavitt path algebra is given in terms of an algebraic property of K,not just a graph-theoretic property of E.This differs from the.known characterizations of various other algebraic properties of a Leavitt path algebra in terms of graphtheoretic properties of E alone.As a corollary,we show that Handelman's conjecture (stating that every *-regular ring is unit-regular) holds for Leavitt path algebras.Moreover,its generalized version for rings with local units also continues to hold for Leavitt path algebras over arbitrary graphs.

  14. Hypermedia Environments and Adaptive Instruction.

    Science.gov (United States)

    Federico, Pat-Anthony

    1999-01-01

    Reviews relevant professional literature concerning hypermedia environments and adaptive instruction for online learning for distance education and continuing education. Highlights include aptitude-treatment interaction; cognitive processes; navigational paths; log files; and intelligent tutors. Contains 125 references. (LRW)

  15. The partial catalytic oxidation of methane to give oxygen-containing compounds

    Science.gov (United States)

    Krylov, Oleg V.

    1992-11-01

    The three principal paths of the partial oxidation of methane, to give methanol, formaldehyde, and synthesis gas, have been reviewed. The kinetics and mechanism of the processes have been described. The possible oxidation of methane using different oxidising agents — oxygen and carbon dioxide — has been examined. The bibliography includes 139 references.

  16. Tortuous path chemical preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Lewis, Patrick R.; Adkins, Douglas R.; Wheeler, David R.; Simonson, Robert J.

    2010-09-21

    A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

  17. Self-calibrating common-path interferometry.

    Science.gov (United States)

    Porras-Aguilar, Rosario; Falaggis, Konstantinos; Ramirez-San-Juan, Julio C; Ramos-Garcia, Ruben

    2015-02-09

    A quantitative phase measuring technique is presented that estimates the object phase from a series of phase shifted interferograms that are obtained in a common-path configuration with unknown phase shifts. The derived random phase shifting algorithm for common-path interferometers is based on the Generalized Phase Contrast theory [pl. Opt.40(2), 268 (2001)10.1063/1.1404846], which accounts for the particular image formation and includes effects that are not present in two-beam interferometry. It is shown experimentally that this technique can be used within common-path configurations employing nonlinear liquid crystal materials as self-induced phase filters for quantitative phase imaging without the need of phase shift calibrations. The advantages of such liquid crystal elements compared to spatial light modulator based solutions are given by the cost-effectiveness, self-alignment, and the generation of diminutive dimensions of the phase filter size, giving unique performance advantages.

  18. Path Optimization Using APSO

    Directory of Open Access Journals (Sweden)

    Deepak Goyal

    2013-07-01

    Full Text Available This paper addresses the malicious node detection and path optimization problem for wireless sensor networks. Malicious node detection in neighborhood is a needed because that node may cause incorrect decisions or energy depletion. In this paper APSO (combination of Artificial bee colony and particular swarm optimization is used to choose an optimized path. Through this improved version we will overcome the disadvantage of local optimal which comes when we use PSO approach.

  19. Differential Equations driven by \\Pi-rough paths

    CERN Document Server

    Gyurkó, Lajos Gergely

    2012-01-01

    This paper revisits the concept of rough paths of inhomogeneous degree of smoothness (geometric \\Pi-rough paths in our terminology) sketched by Lyons ("Differential equations driven by rough signals", Revista Mathematica Iber. Vol 14, Nr. 2,215-310, 1998). Although geometric \\Pi-rough paths can be treated as p-rough paths for a sufficiently large p and the theory of integration of Lip-\\gamma one-forms (\\gamma>p-1) along geometric p-rough paths applies, we prove the existence of integrals of one-forms under weaker conditions. Moreover, we consider differential equations driven by geometric \\Pi-rough paths and give sufficient conditions for existence and uniqueness of solution.

  20. The Effect of Media on Charitable Giving and Volunteering: Evidence from the "Give Five" Campaign

    Science.gov (United States)

    Yoruk, Baris K.

    2012-01-01

    Fundraising campaigns advertised via mass media are common. To what extent such campaigns affect charitable behavior is mostly unknown, however. Using giving and volunteering surveys conducted biennially from 1988 to 1996, I investigate the effect of a national fundraising campaign, "Give Five," on charitable giving and volunteering patterns. The…

  1. Termination of Commercial Contracts by giving Notice

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    2008-01-01

    Some long-term contracts are brought to an end if one of the parties gives notice. Usually, such a step is not considered a breach of contract. It causes the contract to end in accordance with the contract. When no express rules cover the situation, it is often not entirely clear whether or not t......Some long-term contracts are brought to an end if one of the parties gives notice. Usually, such a step is not considered a breach of contract. It causes the contract to end in accordance with the contract. When no express rules cover the situation, it is often not entirely clear whether...

  2. Give and Take in Dictator Games

    DEFF Research Database (Denmark)

    Cappelen, Alexander W.; Nielsen, Ulrik Haagen; Sørensen, Erik Ø.;

    2014-01-01

    It has been shown that participants in the dictator game are less willing to give money to the other participant when their choice set also includes the option to take money. We examine whether this effect is due to the choice set providing a signal about entitlements in a setting where...... in Denmark. The findings are consistent with dictator giving partly being motivated by a desire to signal that one is not entirely selfish or by a desire to follow a social norm that is choice-set dependent....

  3. Conscientious refusals and reason-giving.

    Science.gov (United States)

    Marsh, Jason

    2014-07-01

    Some philosophers have argued for what I call the reason-giving requirement for conscientious refusal in reproductive healthcare. According to this requirement, healthcare practitioners who conscientiously object to administering standard forms of treatment must have arguments to back up their conscience, arguments that are purely public in character. I argue that such a requirement, though attractive in some ways, faces an overlooked epistemic problem: it is either too easy or too difficult to satisfy in standard cases. I close by briefly considering whether a version of the reason-giving requirement can be salvaged despite this important difficulty.

  4. The effect of varying path properties in path steering tasks

    NARCIS (Netherlands)

    Liu, L.; Liere, R. van

    2010-01-01

    Path steering is a primitive 3D interaction task that requires the user to navigate through a path of a given length and width. In a previous paper, we have conducted controlled experiments in which users operated a pen input device to steer a cursor through a 3D path subject to fixed path propertie

  5. SVC VIDEO STREAM ALLOCATION AND ADAPTATION IN HETEROGENEOUS NETWORK

    Directory of Open Access Journals (Sweden)

    E. A. Pakulova

    2016-07-01

    Full Text Available The paper deals with video data transmission in format H.264/SVC standard with QoS requirements satisfaction. The Sender-Side Path Scheduling (SSPS algorithm and Sender-Side Video Adaptation (SSVA algorithm were developed. SSPS algorithm gives the possibility to allocate video traffic among several interfaces while SSVA algorithm dynamically changes the quality of video sequence in relation to QoS requirements. It was shown that common usage of two developed algorithms enables to aggregate throughput of access networks, increase parameters of Quality of Experience and decrease losses in comparison with Round Robin algorithm. For evaluation of proposed solution, the set-up was made. The trace files with throughput of existing public networks were used in experiments. Based on this information the throughputs of networks were limited and losses for paths were set. The results of research may be used for study and transmission of video data in heterogeneous wireless networks.

  6. CAS paleoichthyologist gives Artedi Lecture in Sweden

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Prof. ZHANG Miman (CHANG Mee-mann), a CAS Member from the CAS Institute of Vertebrate Paleontology and Paleoanthropology, was invited to give a talk at the Artedi Lectures at the Royal Swedish Academy of Sciences in Stockholm, Sweden, on 5 December, 2008.

  7. Bidding to give in the field

    NARCIS (Netherlands)

    Onderstal, Sander; Schram, Arthur J. H. C.; Soetevent, Adriaan R.

    2013-01-01

    In a door-to-door fundraising field experiment, we study the impact of fundraising mechanisms on charitable giving. We approached about 4500 households, each participating in an all-pay auction, a lottery, a non-anonymous voluntary contribution mechanism (VCM), or an anonymous VCM. In contrast to th

  8. The Costs and Benefits of Deferred Giving.

    Science.gov (United States)

    Fink, Norman S.; Metzler, Howard C.

    It is argued in this book that while there can be a significant payoff for deferred giving programs, it is important to determine their cost effectiveness. Modern business methods of cost accounting, benefits analysis, and actuarial and econometric forecasting are applied to the Pomona College plan, whose study was supported by Lilly Endowment,…

  9. Shortest Paths in Microseconds

    CERN Document Server

    Agarwal, Rachit; Godfrey, P Brighten; Zhao, Ben Y

    2013-01-01

    Computing shortest paths is a fundamental primitive for several social network applications including socially-sensitive ranking, location-aware search, social auctions and social network privacy. Since these applications compute paths in response to a user query, the goal is to minimize latency while maintaining feasible memory requirements. We present ASAP, a system that achieves this goal by exploiting the structure of social networks. ASAP preprocesses a given network to compute and store a partial shortest path tree (PSPT) for each node. The PSPTs have the property that for any two nodes, each edge along the shortest path is with high probability contained in the PSPT of at least one of the nodes. We show that the structure of social networks enable the PSPT of each node to be an extremely small fraction of the entire network; hence, PSPTs can be stored efficiently and each shortest path can be computed extremely quickly. For a real network with 5 million nodes and 69 million edges, ASAP computes a short...

  10. Faster Replacement Paths

    CERN Document Server

    Williams, Virginia Vassilevska

    2010-01-01

    The replacement paths problem for directed graphs is to find for given nodes s and t and every edge e on the shortest path between them, the shortest path between s and t which avoids e. For unweighted directed graphs on n vertices, the best known algorithm runtime was \\tilde{O}(n^{2.5}) by Roditty and Zwick. For graphs with integer weights in {-M,...,M}, Weimann and Yuster recently showed that one can use fast matrix multiplication and solve the problem in O(Mn^{2.584}) time, a runtime which would be O(Mn^{2.33}) if the exponent \\omega of matrix multiplication is 2. We improve both of these algorithms. Our new algorithm also relies on fast matrix multiplication and runs in O(M n^{\\omega} polylog(n)) time if \\omega>2 and O(n^{2+\\eps}) for any \\eps>0 if \\omega=2. Our result shows that, at least for small integer weights, the replacement paths problem in directed graphs may be easier than the related all pairs shortest paths problem in directed graphs, as the current best runtime for the latter is \\Omega(n^{2.5...

  11. Path Integral Techniques in Conformal Field Theory

    CERN Document Server

    Van Tonder, A J

    2004-01-01

    We present the theory of a two-dimensional conformal scalar field using path integral techniques. We derive the conformal anomaly using an adaptation of the method of Fujikawa, and compare the result with a derivation based on a Pauli-Villars measure, where the anomaly is shifted from the path integral measure to the energy-momentum trace. In the path integral approach the energy-momentum is a true coordinate-invariant tensor quantity, and we explain how it is related to the corresponding non-tensor object arising in the operator approach, obtaining an intuitive explanation within the context of the path integral approach for the anomalous transformation law and anomalous Ward identities of the latter. After carefully calculating nontrivial contact terms arising in certain energy-momentum products, we use these to provide a simple consistency check confirming the change of variables formula for the path integral and to review the relationship between the conformal anomaly and the energy-momentum two-point fun...

  12. Intergenerational Transmission of Religious Giving: Instilling Giving Habits across the Life Course

    Directory of Open Access Journals (Sweden)

    Patricia Snell Herzog

    2016-07-01

    Full Text Available This paper investigates the research question: How do religious youth learn to give? While it is likely that youth learn religious financial giving from a variety of different sources, this investigation focuses primarily on how parents teach giving to their children. Supplementary data are also analyzed on the frequency in which youth hear extra-familial calls to give within their religious congregations. In focusing on parental transmission, the analysis identifies a number of approaches that parents report using to teach their children religious financial giving. It also investigates thoughts and feelings about religious financial giving by the children of these parents as a means of assessing the potential impacts of parental methods. Additionally, congregation member reflections on how they learned to give provide insights on giving as a process that develops across the life course, often instilled in childhood, but not appearing behaviorally until adulthood. As such, this paper contributes to a life course understanding of religious giving and has implications for giving across generations.

  13. Smoothing of Piecewise Linear Paths

    Directory of Open Access Journals (Sweden)

    Michel Waringo

    2008-11-01

    Full Text Available We present an anytime-capable fast deterministic greedy algorithm for smoothing piecewise linear paths consisting of connected linear segments. With this method, path points with only a small influence on path geometry (i.e. aligned or nearly aligned points are successively removed. Due to the removal of less important path points, the computational and memory requirements of the paths are reduced and traversing the path is accelerated. Our algorithm can be used in many different applications, e.g. sweeping, path finding, programming-by-demonstration in a virtual environment, or 6D CNC milling. The algorithm handles points with positional and orientational coordinates of arbitrary dimension.

  14. TRACING EFFICIENT PATH USING WEB PATH TRACING

    Directory of Open Access Journals (Sweden)

    L.K. Joshila Grace

    2014-01-01

    Full Text Available In the fast improving society, people depend on online purchase of goods than spending time physically. So there are lots of resources emerged for this online buying and selling of materials. Efficient and attractive web sites would be the best to sell the goods to people. To know whether a web site is reaching the mind of the customers or not, a high speed analysis is done periodically by the web developers. This works helps for the web site developers in knowing the weaker and stronger section of their web site. Parameters like frequency and utility are used for quantitative and qualitative analysis respectively. Addition to this down loads, book marks and the like/dislike of the particular web site is also considered. A new web path trace tree structure is implemented. A mathematical implementation is done to predict the efficient pattern used by the web site visitors.

  15. Euclidean shortest paths

    CERN Document Server

    Li, Fajie

    2011-01-01

    This unique text/reference reviews algorithms for the exact or approximate solution of shortest-path problems, with a specific focus on a class of algorithms called rubberband algorithms. Discussing each concept and algorithm in depth, the book includes mathematical proofs for many of the given statements. Topics and features: provides theoretical and programming exercises at the end of each chapter; presents a thorough introduction to shortest paths in Euclidean geometry, and the class of algorithms called rubberband algorithms; discusses algorithms for calculating exact or approximate ESPs i

  16. Adaptive Modulation with Channel Estimation in High-Speed Packet-Based OFDM Communication Systems

    Institute of Scientific and Technical Information of China (English)

    HOU Xiao-lin; WU Jun-li; YIN Chang-chuan; YUE Guang-xin

    2004-01-01

    In this paper, adaptive modulation with channel estimation in high-speed packet-based Orthogonal Frequency Division Multiplexing (OFDM) communication systems for beyond 3G are discussed. Different adaptive modulation and channel estimation methods are presented and compared, then those methods suitable for our intended application are chosen. Conclusions can be drawn from computer simulations that with proper selection of packet length and subband width, wide subband adaptive modulation with Least Square plus Discrete-time Fourier Transform (LS-DFT) channel estimation can give an acceptable performance with low complexity for channel with low Doppler shift and small path delay. Otherwise, narrow subband or subcarrier adaptive modulation together with LS-DFT plus Decision Directed (LS-DFT-DD) must be used.

  17. Giving Reasons, A Contribution to Argumentation Theory

    Directory of Open Access Journals (Sweden)

    Lilian Bermejo-Luque

    2011-10-01

    Full Text Available In Giving Reasons: A Linguistic-pragmatic-approach to Argumentation Theory (Springer, 2011, I provide a new model for the semantic and pragmatic appraisal of argumentation. This model is based on a characterization of argumentation as a second order speech-act complex. I explain the advantages of this model respecting other proposals within Argumentation Theory, such as Pragma-dialectics, Informal Logic, the New Rhetoric or the Epistemic Approach.

  18. Reparametrizations of Continuous Paths

    DEFF Research Database (Denmark)

    Fahrenberg, Uli; Raussen, Martin

    2007-01-01

    compare it to the distributive lattice of countable subsets of the unit interval. The results obtained are used to analyse the space of traces in a topological space, i.e., the space of continuous paths up to reparametrization equivalence. This space is shown to be homeomorphic to the space of regular...

  19. MEASURING PATH DEPENDENCY

    Directory of Open Access Journals (Sweden)

    Peter Juhasz

    2017-03-01

    Full Text Available While risk management gained popularity during the last decades even some of the basic risk types are still far out of focus. One of these is path dependency that refers to the uncertainty of how we reach a certain level of total performance over time. While decision makers are careful in accessing how their position will look like the end of certain periods, little attention is given how they will get there through the period. The uncertainty of how a process will develop across a shorter period of time is often “eliminated” by simply choosing a longer planning time interval, what makes path dependency is one of the most often overlooked business risk types. After reviewing the origin of the problem we propose and compare seven risk measures to access path. Traditional risk measures like standard deviation of sub period cash flows fail to capture this risk type. We conclude that in most cases considering the distribution of the expected cash flow effect caused by the path dependency may offer the best method, but we may need to use several measures at the same time to include all the optimisation limits of the given firm

  20. Role-modeling and conversations about giving in the socialization of adolescent charitable giving and volunteering.

    Science.gov (United States)

    Ottoni-Wilhelm, Mark; Estell, David B; Perdue, Neil H

    2014-01-01

    This study investigated the relationship between the monetary giving and volunteering behavior of adolescents and the role-modeling and conversations about giving provided by their parents. The participants are a large nationally-representative sample of 12-18 year-olds from the Panel Study of Income Dynamics' Child Development Supplement (n = 1244). Adolescents reported whether they gave money and whether they volunteered. In a separate interview parents reported whether they talked to their adolescent about giving. In a third interview, parents reported whether they gave money and volunteered. The results show that both role-modeling and conversations about giving are strongly related to adolescents' giving and volunteering. Knowing that both role-modeling and conversation are strongly related to adolescents' giving and volunteering suggests an often over-looked way for practitioners and policy-makers to nurture giving and volunteering among adults: start earlier, during adolescence, by guiding parents in their role-modeling of, and conversations about, charitable giving and volunteering.

  1. Advice on Giving a Scientific Talk

    Science.gov (United States)

    Kurtz, D. W.

    2006-04-01

    What makes one speaker exciting and another boring? You have been to good talks and you have sat through far too many poor ones, so what makes the difference? It doesn't really matter whether it is a scientific talk, a public talk or a classroom lecture: Your prime concern is to think about the audience. You are talking to them. You are performing. Look at them; talk to them; think about what they are hearing and seeing. They very much want you to give a good talk -- that is why they have chosen to be your audience. But at the start of your talk they are worried you might not, so they are nervous. Your first job is to relax them and get their trust that you are going to do a good job. Then you will relax and you will be off to a great start. Of course your content matters; if you have a great discovery, they will forgive you anything. But it is still better to make a good presentation. I give some advice here on what to do, and what not to do, when giving any kind of talk, but with emphasis on short scientific talks presented at conferences. You should be a little nervous at the start of a talk - that is caused by your concern to do a good job. With a good start your talk will flow, you will then present your discoveries, and with a good ending your audience will applaud appreciatively and want to ask you questions. You will have enjoyed performing and want to do it again. Speaking can be fun for you, and rewarding for your audiences.

  2. Nurses' intentions to give lifestyle support.

    Science.gov (United States)

    McKenzie, Karen

    Models of behaviour change can help identify factors that influence health behaviours such as eating a healthy diet and physical activity. The Theory of Planned Behaviour has been shown to be relatively effective at predicting people's intention to engage in health-related behaviours. More recent research has explored whether it can help predict the intentions of one group of people to support another group to engage in healthy behaviour. This has implications for nurses, who are often facilitators of patient health. This article gives an overview of the model and discusses its potential implications for nurses.

  3. Performance analysis of FXLMS algorithm with secondary path modeling error

    Institute of Scientific and Technical Information of China (English)

    SUN Xu; CHEN Duanshi

    2003-01-01

    Performance analysis of filtered-X LMS (FXLMS) algorithm with secondary path modeling error is carried out in both time and frequency domain. It is shown firstly that the effects of secondary path modeling error on the performance of FXLMS algorithm are determined by the distribution of the relative error of secondary path model along with frequency.In case of that the distribution of relative error is uniform the modeling error of secondary path will have no effects on the performance of the algorithm. In addition, a limitation property of FXLMS algorithm is proved, which implies that the negative effects of secondary path modeling error can be compensated by increasing the adaptive filter length. At last, some insights into the "spillover" phenomenon of FXLMS algorithm are given.

  4. Financing climate change adaptation.

    Science.gov (United States)

    Bouwer, Laurens M; Aerts, Jeroen C J H

    2006-03-01

    This paper examines the topic of financing adaptation in future climate change policies. A major question is whether adaptation in developing countries should be financed under the 1992 United Nations Framework Convention on Climate Change (UNFCCC), or whether funding should come from other sources. We present an overview of financial resources and propose the employment of a two-track approach: one track that attempts to secure climate change adaptation funding under the UNFCCC; and a second track that improves mainstreaming of climate risk management in development efforts. Developed countries would need to demonstrate much greater commitment to the funding of adaptation measures if the UNFCCC were to cover a substantial part of the costs. The mainstreaming of climate change adaptation could follow a risk management path, particularly in relation to disaster risk reduction. 'Climate-proofing' of development projects that currently do not consider climate and weather risks could improve their sustainability.

  5. Nonadiabatic transition path sampling

    Science.gov (United States)

    Sherman, M. C.; Corcelli, S. A.

    2016-07-01

    Fewest-switches surface hopping (FSSH) is combined with transition path sampling (TPS) to produce a new method called nonadiabatic path sampling (NAPS). The NAPS method is validated on a model electron transfer system coupled to a Langevin bath. Numerically exact rate constants are computed using the reactive flux (RF) method over a broad range of solvent frictions that span from the energy diffusion (low friction) regime to the spatial diffusion (high friction) regime. The NAPS method is shown to quantitatively reproduce the RF benchmark rate constants over the full range of solvent friction. Integrating FSSH within the TPS framework expands the applicability of both approaches and creates a new method that will be helpful in determining detailed mechanisms for nonadiabatic reactions in the condensed-phase.

  6. Cosmological Feynman Paths

    CERN Document Server

    Chew, Geoffrey F

    2008-01-01

    Arrowed-time divergence-free rules or cosmological quantum dynamics are formulated through stepped Feynman paths across macroscopic slices of Milne spacetime. Slice boundaries house totally-relativistic rays representing elementary entities--preons. Total relativity and the associated preon Fock space, despite distinction from special relativity (which lacks time arrow), are based on the Lorentz group. Each path is a set of cubic vertices connected by straight, directed and stepped arcs that carry inertial, electromagnetic and gravitational action. The action of an arc step comprises increments each bounded by Planck's constant. Action from extremely-distant sources is determined by universe mean energy density. Identifying the arc-step energy that determines inertial action with that determining gravitational action establishes both arc-step length and universe density. Special relativity is accurate for physics at laboratory spacetime scales far below that of Hubble and far above that of Planck.

  7. Quad-rotor flight path energy optimization

    Science.gov (United States)

    Kemper, Edward

    Quad-Rotor unmanned areal vehicles (UAVs) have been a popular area of research and development in the last decade, especially with the advent of affordable microcontrollers like the MSP 430 and the Raspberry Pi. Path-Energy Optimization is an area that is well developed for linear systems. In this thesis, this idea of path-energy optimization is extended to the nonlinear model of the Quad-rotor UAV. The classical optimization technique is adapted to the nonlinear model that is derived for the problem at hand, coming up with a set of partial differential equations and boundary value conditions to solve these equations. Then, different techniques to implement energy optimization algorithms are tested using simulations in Python. First, a purely nonlinear approach is used. This method is shown to be computationally intensive, with no practical solution available in a reasonable amount of time. Second, heuristic techniques to minimize the energy of the flight path are tested, using Ziegler-Nichols' proportional integral derivative (PID) controller tuning technique. Finally, a brute force look-up table based PID controller is used. Simulation results of the heuristic method show that both reliable control of the system and path-energy optimization are achieved in a reasonable amount of time.

  8. Damage detection using frequency shift path

    Science.gov (United States)

    Wang, Longqi; Lie, Seng Tjhen; Zhang, Yao

    2016-01-01

    This paper introduces a novel concept called FREquency Shift (FRESH) path to describe the dynamic behavior of structures with auxiliary mass. FRESH path combines the effects of frequency shifting and amplitude changing into one space curve, providing a tool for analyzing structure health status and properties. A damage index called FRESH curvature is then proposed to detect local stiffness reduction. FRESH curvature can be easily adapted for a particular problem since the sensitivity of the index can be adjusted by changing auxiliary mass or excitation power. An algorithm is proposed to adjust automatically the contribution from frequency and amplitude in the method. Because the extraction of FRESH path requires highly accurate frequency and amplitude estimators; therefore, a procedure based on discrete time Fourier transform is introduced to extract accurate frequency and amplitude with the time complexity of O (n log n), which is verified by simulation signals. Moreover, numerical examples with different damage sizes, severities and damping are presented to demonstrate the validity of the proposed damage index. In addition, applications of FRESH path on two steel beams with different damages are presented and the results show that the proposed method is valid and computational efficient.

  9. Learning to improve path planning performance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pang C.

    1995-04-01

    In robotics, path planning refers to finding a short. collision-free path from an initial robot configuration to a desired configuratioin. It has to be fast to support real-time task-level robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To remedy this situation, we present and analyze a learning algorithm that uses past experience to increase future performance. The algorithm relies on an existing path planner to provide solutions to difficult tasks. From these solutions, an evolving sparse network of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a speedup-learning framework in which a slow but capable planner may be improved both cost-wise and capability-wise by a faster but less capable planner coupled with experience. The basic algorithm is suitable for stationary environments, and can be extended to accommodate changing environments with on-demand experience repair and object-attached experience abstraction. To analyze the algorithm, we characterize the situations in which the adaptive planner is useful, provide quantitative bounds to predict its behavior, and confirm our theoretical results with experiments in path planning of manipulators. Our algorithm and analysis are sufficiently, general that they may also be applied to other planning domains in which experience is useful.

  10. PATHS groundwater hydrologic model

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.W.; Schur, J.A.

    1980-04-01

    A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

  11. Giving Devices the Ability to Exercise Reason

    Directory of Open Access Journals (Sweden)

    Thomas Keeley

    2008-10-01

    Full Text Available One of the capabilities that separates humans from computers has been the ability to exercise "reason / judgment". Computers and computerized devices have provided excellent platforms for following rules. Computer programs provide the scripts for processing the rules. The exercise of reason, however, is more of an image processing function than a function composed of a series of rules. The exercise of reason is more right brain than left brain. It involves the interpretation of information and balancing inter-related alternatives. This paper will discuss a new way to define and process information that will give devices the ability to exercise human-like reasoning and judgment. The paper will discuss the characteristics of a "dynamic graphical language" in the context of addressing judgment, since judgment is often required to adjust rules when operating in a dynamic environment. The paper will touch on architecture issues and how judgment is integrated with rule processing.

  12. The Luxury of Igniting Change by Giving

    DEFF Research Database (Denmark)

    Llamas, Rosa; Uth Thomsen, Thyra

    2016-01-01

    This study investigates the phenomenon of luxury from a consumer perspective, by means of multisited phenomenological inquiry. The findings expand the pervasive view of luxury as accumulation of highly valued goods by offering a transformative perspective of luxury as transforming the life...... the giver with a sense of luxury in terms of pleasure, purpose, and connection with humankind. Thus, the findings not only extend the traditional conceptualization of luxury from having to giving, but also challenge current conceptualizations of sharing out as a non-reciprocal pro-social behavior...... by illustrating how ‘the luxury of giving’ relies on both pro-social and pro-ego consumption rationales, which implicitly include circular reciprocation....

  13. Quantum Measurement and Extended Feynman Path Integral

    Institute of Scientific and Technical Information of China (English)

    文伟; 白彦魁

    2012-01-01

    Quantum measurement problem has existed many years and inspired a large of literature in both physics and philosophy, but there is still no conclusion and consensus on it. We show it can be subsumed into the quantum theory if we extend the Feynman path integral by considering the relativistic effect of Feynman paths. According to this extended theory, we deduce not only the Klein-Gordon equation, but also the wave-function-collapse equation. It is shown that the stochastic and instantaneous collapse of the quantum measurement is due to the "potential noise" of the apparatus or environment and "inner correlation" of wave function respectively. Therefore, the definite-status of the macroscopic matter is due to itself and this does not disobey the quantum mechanics. This work will give a new recognition for the measurement problem.

  14. Path planning in dynamic environments

    NARCIS (Netherlands)

    Berg, J.P. van den

    2007-01-01

    Path planning plays an important role in various fields of application, such as CAD design, computer games and virtual environments, molecular biology, and robotics. In its most general form, the path planning problem is formulated as finding a collision-free path for a moving entity between a start

  15. Broadband Phase Spectroscopy over Turbulent Air Paths.

    Science.gov (United States)

    Giorgetta, Fabrizio R; Rieker, Gregory B; Baumann, Esther; Swann, William C; Sinclair, Laura C; Kofler, Jon; Coddington, Ian; Newbury, Nathan R

    2015-09-01

    Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mode path combined with the intrinsic frequency stability and high sampling speed associated with dual-comb spectroscopy. The atmospheric phase spectrum is measured across 2 km of air at each of the 70,000 comb teeth spanning 233  cm(-1) across hundreds of near-infrared rovibrational resonances of CO(2), CH(4), and H(2)O with submilliradian uncertainty, corresponding to a 10(-13) refractive index sensitivity. Trace gas concentrations extracted directly from the phase spectrum reach 0.7 ppm uncertainty, demonstrated here for CO(2). While conventional broadband spectroscopy only measures intensity absorption, this approach enables measurement of the full complex susceptibility even in practical open path sensing.

  16. Approximation algorithms for curvature-constrained shortest paths

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyan; Agarwal, P.K. [Duke Univ., Durham, NC (United States)

    1996-12-31

    Let B be a point robot in the plane, whose path is constrained to have curvature of at most 1, and let {Omega} be a set of polygonal obstacles with n vertices. We study the collision-free, optimal path-planning problem for B. Given a parameter {epsilon}, we present an O((n{sup 2}/{epsilon}{sup 2}) log n)-time algorithm for computing a collision-free, curvature-constrained path between two given positions, whose length is at most (1 + {epsilon}) times the length of an optimal robust path (a path is robust if it remains collision-free even if certain positions on the path are perturbed). Our algorithm thus runs significantly faster than the previously best known algorithm by Jacobs and Canny whose running time is O((n+L/{epsilon}){sup 2} + n{sup 2} (n+1/{epsilon}) log n), where L is the total edge length of the obstacles. More importantly, the running time of our algorithm does not depend on the size of obstacles. The path returned by this algorithm is not necessarily robust. We present an O((n/{epsilon}){sup 2.5} log n)-time algorithm that returns a robust path whose length is at most (1 + {epsilon}) times the length of an optimal robust path. We also give a stronger characterization of curvature-constrained shortest paths, which, apart from being crucial for our algorithm, is interesting in its own right. Roughly speaking, we prove that, except in some special cases, a shortest path touches obstacles only at points that have a visible vertex nearby.

  17. Bangladesh: giving girls the "key of keys".

    Science.gov (United States)

    Chhabra, R

    1998-01-01

    In Bangladesh, 100 nongovernmental organizations (NGOs) have worked with the government to create approximately 52,000 nonformal schools for children who have never attended school or have dropped out. The Bangladesh Rural Advancement Committee (BRAC) alone has 34,000 nonformal education centers. The BRAC program has been particularly effective at increasing educational opportunities for girls, and BRAC is a major implementing agency of the agreement forged by the International Labor Organization and the UN Children's Fund with the Bangladesh Garment Manufacturers Export Association, which gives about 10,000 former child garment workers a meager stipend allowing them to study instead of work. BRAC, the Grameen Bank, and several other NGOs are also developing alternative income-generating methods to compete with the exploitative working conditions suffered by impoverished girls. BRAC now has more than a million students enrolled each year, 700,000 of whom are girls. Students participate in special condensed courses in classes that average 33 pupils (20 must be girls). Gender sensitivity is incorporated at every level. BRAC also relies on community participation in running the schools, and the flexible hours and imaginative curriculum have resulted in very high attendance rates. Government actions (making primary education compulsory and tripling education expenditure) have also resulted in increased primary enrollment while special programs seek to increase the number of girls in secondary schools.

  18. Direct Path Detection Method in Indoor Location

    Institute of Scientific and Technical Information of China (English)

    HUA Hu; LI Zheng

    2006-01-01

    A search algorithm for the detection of a direct path signal in the presence of dense multipath in indoor environment using UWB is Proposed. This algorithm is based on signal correlation and differential coefficient. Statistical analysis of the algorithm is given out and computer simulation results are presented to validate the effectiveness of the algorithm.The results based on the algorithm proposed are compared with those based on Maximum Likelihood Estimator(MLE)and Peak Tracking(PT)in the simulation which shows that this algorithm achieves the highest accuracy in most cases and gives out relatively stable results in different Signal Noise Ratio(SNR).

  19. Path Through the Wheat

    Directory of Open Access Journals (Sweden)

    David Middleton

    2005-01-01

    Full Text Available The hillside’s tidal waves of yellow-green Break downward into full-grown stalks of wheat In which a peasant, shouldering his hoe Passes along a snaking narrow path -- A teeming place through which his hard thighs press And where his head just barely stays above The swaying grain, drunken in abundance, Farm buildings almost floating on the swells Beyond which sea gulls gliding white in air Fly down on out of sight to salty fields, Taking the channel fish off Normandy, A surfeit fit for Eden i...

  20. JAVA PathFinder

    Science.gov (United States)

    Mehhtz, Peter

    2005-01-01

    JPF is an explicit state software model checker for Java bytecode. Today, JPF is a swiss army knife for all sort of runtime based verification purposes. This basically means JPF is a Java virtual machine that executes your program not just once (like a normal VM), but theoretically in all possible ways, checking for property violations like deadlocks or unhandled exceptions along all potential execution paths. If it finds an error, JPF reports the whole execution that leads to it. Unlike a normal debugger, JPF keeps track of every step how it got to the defect.

  1. Rocket Flight Path

    Directory of Open Access Journals (Sweden)

    Jamie Waters

    2014-09-01

    Full Text Available This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

  2. Cognitive patterns: giving autonomy some context

    Science.gov (United States)

    Dumond, Danielle; Stacy, Webb; Geyer, Alexandra; Rousseau, Jeffrey; Therrien, Mike

    2013-05-01

    Today's robots require a great deal of control and supervision, and are unable to intelligently respond to unanticipated and novel situations. Interactions between an operator and even a single robot take place exclusively at a very low, detailed level, in part because no contextual information about a situation is conveyed or utilized to make the interaction more effective and less time consuming. Moreover, the robot control and sensing systems do not learn from experience and, therefore, do not become better with time or apply previous knowledge to new situations. With multi-robot teams, human operators, in addition to managing the low-level details of navigation and sensor management while operating single robots, are also required to manage inter-robot interactions. To make the most use of robots in combat environments, it will be necessary to have the capability to assign them new missions (including providing them context information), and to have them report information about the environment they encounter as they proceed with their mission. The Cognitive Patterns Knowledge Generation system (CPKG) has the ability to connect to various knowledge-based models, multiple sensors, and to a human operator. The CPKG system comprises three major internal components: Pattern Generation, Perception/Action, and Adaptation, enabling it to create situationally-relevant abstract patterns, match sensory input to a suitable abstract pattern in a multilayered top-down/bottom-up fashion similar to the mechanisms used for visual perception in the brain, and generate new abstract patterns. The CPKG allows the operator to focus on things other than the operation of the robot(s).

  3. Adaptive Learning Management System

    Directory of Open Access Journals (Sweden)

    Violeta Moisa

    2013-06-01

    Full Text Available This article is an introduction to a new model for an adaptive Learning Management System. It presents the current e-learning standards and describes the elements that can be used to create the system: the sequencing control modes, sequencing rules, navigation controls, learning records and learning record stores. The model is based on artificial intelligent algorithms that analyze the data captured for each user and creates an adaptive navigation path through the learning content of the system, allowing each user to experience the content in different ways

  4. First exit distribution and path continuity of Hunt processes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui-zeng; KANG Xu-sheng; ZHAO Min-zhi

    2009-01-01

    This paper gives a characterization of a Hunt process path by the first exit left limit distribution. It is also showed that if the first exit left limit distribution leaving any ball from the center is a uniform distribution on the sphere, then the Lévy Processes are a scaled Brownian motion.

  5. Ranking paths in stochastic time-dependent networks

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Andersen, Kim Allan; Pretolani, Daniele D.

    2014-01-01

    be easily extended to the ranking of the first K shortest paths. Our method exploits the solution of the time-adaptive routing problem as a relaxation of the a priori problem. Computational results are presented showing that, under realistic distributions of travel times and costs, our solution methods...

  6. Emotional Intelligence Abilities and Traits in Different Career Paths

    Science.gov (United States)

    Kafetsios, Konstantinos; Maridaki-Kassotaki, Aikaterini; Zammuner, Vanda L.; Zampetakis, Leonidas A.; Vouzas, Fotios

    2009-01-01

    Two studies tested hypotheses about differences in emotional intelligence (EI) abilities and traits between followers of different career paths. Compared to their social science peers, science students had higher scores in adaptability and general mood traits measured with the Emotion Quotient Inventory, but lower scores in strategic EI abilities…

  7. Path planning for steerable needles using duty-cycled spinning

    Directory of Open Access Journals (Sweden)

    Borges G.A.

    2011-12-01

    Full Text Available This paper presents an adaptive approach for 2D path planning of steerable needles. It combines dutycycled rotation of the needle with the classic RapidlyExploring Random Tree (RRT algorithm and it is used intraoperatively to compensate for system uncertainties and perturbations. Simulation results demonstrate the performance of the proposed motion planner on a workspace based in ultrasound images.

  8. Teaching Techniques: Give or Take? Test Review in the ESL/EFL Classroom

    Science.gov (United States)

    Mermelstein, Aaron David

    2016-01-01

    This article describes "Give or Take?", a fun game that teachers can use to review vocabulary in the English as a second language or foreign language (ESL/EFL) classroom. This game is easy to prepare, and it is a fun and efficient way to review for quizzes or larger midterm or final exams. It can be adapted to almost any grade level or…

  9. AUV Local Path Planning Based on Acoustic Image Processing

    Institute of Scientific and Technical Information of China (English)

    LI Ye; CHANG Wen-tian; JIANG Da-peng; ZHANG Tie-dong; SU Yu-min

    2006-01-01

    The forward-looking image sonar is a necessary vision device for Autonomous Underwater Vehicles (AUV). Based on the acoustic image received from forward-looking image sonar, AUV local path is planned. When the environment model is made to adapt to local path planning, an iterative algorithm of binary conversion is used for image segmentation. Raw data of the acoustic image, which were received from serial port, are processed. By the use of "Mathematic Morphology" to filter noise, a mathematic model of environment for local path planning is established after coordinate transformation. The optimal path is searched by the distant transmission (Dt) algorithm. Simulation is conducted for the analysis of the algorithm. Experiment on the sea proves it reliable.

  10. Optimal Path Selection for Mobile Robot Navigation Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    D Tamilselvi

    2011-07-01

    Full Text Available The proposed Navigation Strategy using GA(Genetic Algorithm finds an optimal path in the simulated grid environment. GA forces to find a path that is connected to the robot start and target positions via predefined points. Each point in the environmental model is called genome and the path connecting Start and Target is called as Chromosome. According to the problem formulation, the length of the algorithm chromosomes (number of genomes is dynamic. Moreover every genome is not a simple digit. In this case, every genome represents the nodes in the 2D grid environment. After implementing the cross over and mutation concepts the resultant chromosome (path is subjected to optimization process which gives the optimal path as a result. The problem faced with is there may be chances for the loss of the fittest chromosome while performing the reproduction operations. The solution is achieved by inducing the concept of elitism thereby maintaining the population richness. The efficiency of the algorithm is analyzed with respect to execution time and path cost to reach the destination. Path planning, collision avoidance and obstacle avoidance are achieved in both static and dynamic environment.

  11. Shortest Paths and Vehicle Routing

    DEFF Research Database (Denmark)

    Petersen, Bjørn

    This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle R...... Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown.......This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle...

  12. Path integrals for awkward actions

    CERN Document Server

    Amdahl, David

    2016-01-01

    Time derivatives of scalar fields occur quadratically in textbook actions. A simple Legendre transformation turns the lagrangian into a hamiltonian that is quadratic in the momenta. The path integral over the momenta is gaussian. Mean values of operators are euclidian path integrals of their classical counterparts with positive weight functions. Monte Carlo simulations can estimate such mean values. This familiar framework falls apart when the time derivatives do not occur quadratically. The Legendre transformation becomes difficult or so intractable that one can't find the hamiltonian. Even if one finds the hamiltonian, it usually is so complicated that one can't path-integrate over the momenta and get a euclidian path integral with a positive weight function. Monte Carlo simulations don't work when the weight function assumes negative or complex values. This paper solves both problems. It shows how to make path integrals without knowing the hamiltonian. It also shows how to estimate complex path integrals b...

  13. innovation path exploration

    Directory of Open Access Journals (Sweden)

    Li Jian

    2016-01-01

    Full Text Available The world has entered the information age, all kinds of information technologies such as cloud technology, big data technology are in rapid development, and the “Internet plus” appeared. The main purpose of “Internet plus” is to provide an opportunity for the further development of the enterprise, the enterprise technology, business and other aspects of factors combine. For enterprises, grasp the “Internet plus” the impact of the market economy will undoubtedly pave the way for the future development of enterprises. This paper will be on the innovation path of the enterprise management “Internet plus” era tied you study, hope to be able to put forward some opinions and suggestions.

  14. Entanglement by Path Identity

    CERN Document Server

    Krenn, Mario; Lahiri, Mayukh; Zeilinger, Anton

    2016-01-01

    Quantum entanglement is one of the most prominent features of quantum mechanics and forms the basis of quantum information technologies. Here we present a novel method for the creation of quantum entanglement in multipartite and high-dimensional photonic systems, exploiting an idea introduced by the group of Leonard Mandel 25 years ago. The two ingredients are 1) superposition of photon pairs with different origins and 2) aligning photon paths such that they emerge from the same output mode. We explain examples for the creation of various classes of multiphoton entanglement encoded in polarization as well as in high-dimensional Hilbert spaces -- starting only from separable (non-entangled) photon pairs. For two photons, we show how arbitrary high-dimensional entanglement can be created. Interestingly, a common source for two-photon polarization entanglement is found as a special case. We discovered the technique by analyzing the output of a computer algorithm designing quantum experiments, and generalized it ...

  15. Propagators and path integrals

    Energy Technology Data Exchange (ETDEWEB)

    Holten, J.W. van

    1995-08-22

    Path-integral expressions for one-particle propagators in scalar and fermionic field theories are derived, for arbitrary mass. This establishes a direct connection between field theory and specific classical point-particle models. The role of world-line reparametrization invariance of the classical action and the implementation of the corresponding BRST-symmetry in the quantum theory are discussed. The presence of classical world-line supersymmetry is shown to lead to an unwanted doubling of states for massive spin-1/2 particles. The origin of this phenomenon is traced to a `hidden` topological fermionic excitation. A different formulation of the pseudo-classical mechanics using a bosonic representation of {gamma}{sub 5} is shown to remove these extra states at the expense of losing manifest supersymmetry. (orig.).

  16. Finding Heavy Paths in Graphs: A Rank Join Approach

    CERN Document Server

    Khabbaz, Mohammad; Lakshmanan, Laks V S

    2011-01-01

    In applications such as playlist recommendation, flow analysis in information networks, and itinerary planning, we face the problem of finding the heaviest path(s) in a graph under a given length constraint. More precisely, in these applications, we are given a graph with non-negative edge weights, and a monotone function such as sum, which aggregates edge weights into a single value that defines a path weight. We are required to find the top-$k$ heaviest simple paths, i.e., the $k$ simple (i.e., cycle-free) paths with the greatest weight, whose length equals a given parameter $\\ell$. We call this the Heavy Path Problem (HPP). The problem is known to be NP-Hard, and in general not approximable. In this work, we develop a practical approach to solve the Heavy Path problem by establishing a strong connection with the well-known Rank Join paradigm. We present an adaptation of the Rank Join algorithm and tailor it to self-joins over the list of edges. We present novel thresholding strategies and develop exact and...

  17. Path indexing for term retrieval

    OpenAIRE

    1992-01-01

    Different methods for term retrieval in deduction systems have been introduced in literature. This report eviews the three indexing techniques discrimination indexing, path indexing, and abstraction tree indexing. A formal approach to path indexing is presented and algorithms as well as data structures of an existing implementation are discussed. Eventually, experiments will show that our implementation outperforms the implementation of path indexing in the OTTER theorem prover.

  18. Path integral in Snyder space

    Energy Technology Data Exchange (ETDEWEB)

    Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Štrajn, R. [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy)

    2016-04-29

    The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

  19. An introduction to critical paths.

    Science.gov (United States)

    Coffey, Richard J; Richards, Janet S; Remmert, Carl S; LeRoy, Sarah S; Schoville, Rhonda R; Baldwin, Phyllis J

    2005-01-01

    A critical path defines the optimal sequencing and timing of interventions by physicians, nurses, and other staff for a particular diagnosis or procedure. Critical paths are developed through collaborative efforts of physicians, nurses, pharmacists, and others to improve the quality and value of patient care. They are designed to minimize delays and resource utilization and to maximize quality of care. Critical paths have been shown to reduce variation in the care provided, facilitate expected outcomes, reduce delays, reduce length of stay, and improve cost-effectiveness. The approach and goals of critical paths are consistent with those of total quality management (TQM) and can be an important part of an organization's TQM process.

  20. Rethinking the social and cultural dimensions of charitable giving

    DEFF Research Database (Denmark)

    Bajde, Domen

    2009-01-01

    Gifts to distant others, such as charitable giving, represent an important segment of contemporary gift-giving that has often been overlooked due to the excessive focus on dyadic giving between intimate individuals. In response, this paper adopts a sociological systemic perspective on gift......-giving and focuses on charitable gifts as an emblem of postmodern gift-giving to distant others. Historical evidence and sociological theory on postmodern solidarity are combined to shed light on the fluid duality of contemporary giving and the importance of the imaginary in charitable giving. The outlined socially...

  1. Two Generations of Path Dependence

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

      Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences - primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

  2. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result...

  3. Sustainable Energy Path

    Directory of Open Access Journals (Sweden)

    Hiromi Yamamoto

    2005-12-01

    Full Text Available The uses of fossil fuels cause not only the resources exhaustion but also the environmental problems such as global warming. The purposes of this study are to evaluate paths toward sustainable energy systems and roles of each renewable. In order to realize the purposes, the authors developed the global land use and energy model that figured the global energy supply systems in the future considering the cost minimization. Using the model, the authors conducted a simulation in C30R scenario, which is a kind of strict CO2 emission limit scenarios and reduced CO2 emissions by 30% compared with Kyoto protocol forever scenario, and obtained the following results. In C30R scenario bioenergy will supply 33% of all the primary energy consumption. However, wind and photovoltaic will supply 1.8% and 1.4% of all the primary energy consumption, respectively, because of the limits of power grid stability. The results imply that the strict limits of CO2 emissions are not sufficient to achieve the complete renewable energy systems. In order to use wind and photovoltaic as major energy resources, we need not only to reduce the plant costs but also to develop unconventional renewable technologies.

  4. Adapting agriculture to climate change

    NARCIS (Netherlands)

    Howden, S.M.; Soussana, J.F.; Tubiello, F.N.; Chhetri, N.; Dunlop, M.; Meinke, H.B.

    2007-01-01

    The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are many potential adaptation options available for marginal change of exi

  5. LP-Based Approximation Algorithms for Traveling Salesman Path Problems

    CERN Document Server

    An, Hyung-Chan

    2011-01-01

    We present a (5/3 - epsilon)-approximation algorithm for some constant epsilon>0 for the traveling salesman path problem under the unit-weight graphical metric, and prove an upper bound on the integrality gap of the path-variant Held-Karp relaxation both under this metric and the general metric. Given a complete graph with the metric cost and two designated endpoints in the graph, the traveling salesman path problem is to find a minimum Hamiltonian path between these two endpoints. The best previously known performance guarantee for this problem was 5/3 and was due to Hoogeveen. We give the first constant upper bound on the integrality gap of the path-variant Held-Karp relaxation, showing it to be at most 5/3 by providing a new analysis of Hoogeveen's algorithm. This analysis exhibits a well-characterized critical case, and we show that the recent result of Oveis Gharan, Saberi and Singh on the traveling salesman circuit problem under the unit-weight graphical metric can be modified for the path case to compl...

  6. On the direct path problem of s-elementary frame wavelets

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we discuss the path-connectivity between two s-elementary normalized tight frame wavelets via the so-called direct paths. We show that the existence of such a direct path is equivalent to the non-existence of an atom of a σ-algebra defined over the defining sets of the corresponding frame wavelets, using a mapping defined by the natural translation and dilation operations between the sets. In particular, this gives an equivalent condition for the existence of a direct path between two s-elementary wavelets.

  7. 14 CFR 23.57 - Takeoff path.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff path. 23.57 Section 23.57... path. For each commuter category airplane, the takeoff path is as follows: (a) The takeoff path extends... completed; and (1) The takeoff path must be based on the procedures prescribed in § 23.45; (2) The...

  8. Deep Learning Driven Visual Path Prediction From a Single Image

    Science.gov (United States)

    Huang, Siyu; Li, Xi; Zhang, Zhongfei; He, Zhouzhou; Wu, Fei; Liu, Wei; Tang, Jinhui; Zhuang, Yueting

    2016-12-01

    Capabilities of inference and prediction are significant components of visual systems. In this paper, we address an important and challenging task of them: visual path prediction. Its goal is to infer the future path for a visual object in a static scene. This task is complicated as it needs high-level semantic understandings of both the scenes and motion patterns underlying video sequences. In practice, cluttered situations have also raised higher demands on the effectiveness and robustness of the considered models. Motivated by these observations, we propose a deep learning framework which simultaneously performs deep feature learning for visual representation in conjunction with spatio-temporal context modeling. After that, we propose a unified path planning scheme to make accurate future path prediction based on the analytic results of the context models. The highly effective visual representation and deep context models ensure that our framework makes a deep semantic understanding of the scene and motion pattern, consequently improving the performance of the visual path prediction task. In order to comprehensively evaluate the model's performance on the visual path prediction task, we construct two large benchmark datasets from the adaptation of video tracking datasets. The qualitative and quantitative experimental results show that our approach outperforms the existing approaches and owns a better generalization capability.

  9. Geodesic flows on path spaces

    Institute of Scientific and Technical Information of China (English)

    XIANG; Kainan

    2001-01-01

    [1] Cruzeiro, A. B., Malliavin, P., Renormalized differential geometry on path spaces: Structural equation, curvature, J. Funct. Anal., 1996, 139: 119-181.[2] Stroock, D. W., Some thoughts about Riemannian structures on path spaces, preprint, 1996.[3] Driver, B., A Cameron-Martin type quasi-invariance theorem for Brownian motion on a compact manifold, J. Funct. Anal., 1992, 109: 272-376.[4] Enchev, O., Stroock, D. W., Towards a Riemannian geometry on the path space over a Riemannian manifold, J. Funct. Anal., 1995, 134: 392-416.[5] Hsu, E., Quasi-invariance of the Wiener measure on the path space over a compact Riemannian manifold, J. Funct. Anal., 1995, 134: 417-450.[6] Lyons, T. J., Qian, Z. M., A class of vector fields on path space, J.Funct. Anal., 1997, 145: 205-223.[7] Li, X. D., Existence and uniqueness of geodesics on path spaces, J. Funct. Anal., to be published.[8] Driver, B., Towards calculus and geometry on path spaces, in Proc. Symp. Pure and Appl. Math. 57 (ed. Cranston, M., Pinsky, M.), Cornell: AMS, 1993, 1995.

  10. Adaptive Path Control of Surface Ships in Restricted Waters.

    Science.gov (United States)

    1980-08-01

    about the rudder model included in eq. (11), we assume exact knowledge of the rudder angle. Astrom and K9llstr6m18 note that all sensors have...properties of the ship o 11 and the control loop. Further, Astrom and Wittenmark have noted the fol- lowing conditions as necessary for the convergence...Symposium, VeL. 4, Annapolis, MD., Oct. 30-Nov. 3, 1978, pp. P 1-1 to P 1-13. 1-. Astrom , K.J., "Some Aspwcts, of the Control of Large Tankers

  11. On the Reaction Path Hamiltonian

    Institute of Scientific and Technical Information of China (English)

    孙家钟; 李泽生

    1994-01-01

    A vector-fiber bundle structure of the reaction path Hamiltonian, which has been introduced by Miller, Handy and Adams, is explored with respect to molecular vibrations orthogonal to the reaction path. The symmetry of the fiber bundle is characterized by the real orthogonal group O(3N- 7) for the dynamical system with N atoms. Under the action of group O(3N- 7). the kinetic energy of the reaction path Hamiltonian is left invariant. Furthermore , the invariant behaviour of the Hamiltonian vector fields is investigated.

  12. Path integrals and quantum processes

    CERN Document Server

    Swanson, Marc S

    1992-01-01

    In a clearly written and systematic presentation, Path Integrals and Quantum Processes covers all concepts necessary to understand the path integral approach to calculating transition elements, partition functions, and source functionals. The book, which assumes only a familiarity with quantum mechanics, is ideal for use as a supplemental textbook in quantum mechanics and quantum field theory courses. Graduate and post-graduate students who are unfamiliar with the path integral will also benefit from this contemporary text. Exercise sets are interspersed throughout the text to facilitate self-

  13. Line-of-Sight Path Following for Dubins Paths with Adaptive Sideslip Compensation of Drift Forces

    DEFF Research Database (Denmark)

    Fossen, Thor Inge; Pettersen, Kristin Ytterstad; Galeazzi, Roberto

    2015-01-01

    guidance law is intended for maneuvering in the horizontal-plane at given speeds and typical applications are marine craft, autonomous underwater vehicles (AUVs), unmanned aerial vehicles (UAVs) as well as other vehicles and craft where the goal is to follow a predefined parametrized curve without time...

  14. Ask-Elle: An Adaptable Programming Tutor for Haskell Giving Automated Feedback

    Science.gov (United States)

    Gerdes, Alex; Heeren, Bastiaan; Jeuring, Johan; van Binsbergen, L. Thomas

    2017-01-01

    Ask-Elle is a tutor for learning the higher-order, strongly-typed functional programming language Haskell. It supports the stepwise development of Haskell programs by verifying the correctness of incomplete programs, and by providing hints. Programming exercises are added to Ask-Elle by providing a task description for the exercise, one or more…

  15. Solving the replacement paths problem for planar directed graphs in O(logn) time

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    2010-01-01

    In a graph G with non-negative edge lengths, let P be a shortest path from a vertex s to a vertex t. We consider the problem of computing, for each edge e on P, the length of a shortest path in G from s to t that avoids e. This is known as the replacement paths problem. We give a linearspace algo...

  16. The Internet's unexploited path diversity

    CERN Document Server

    Arjona-Villicaña, Pedro David; Stepanenko, Alexander S

    2009-01-01

    The connectivity of the Internet at the Autonomous System level is influenced by the network operator policies implemented. These in turn impose a direction to the announcement of address advertisements and, consequently, to the paths that can be used to reach back such destinations. We propose to use directed graphs to properly represent how destinations propagate through the Internet and the number of arc-disjoint paths to quantify this network's path diversity. Moreover, in order to understand the effects that policies have on the connectivity of the Internet, numerical analyses of the resulting directed graphs were conducted. Results demonstrate that, even after policies have been applied, there is still path diversity which the Border Gateway Protocol cannot currently exploit.

  17. An Introduction to Path Analysis

    Science.gov (United States)

    Wolfe, Lee M.

    1977-01-01

    The analytical procedure of path analysis is described in terms of its use in nonexperimental settings in the social sciences. The description assumes a moderate statistical background on the part of the reader. (JKS)

  18. Scattering theory with path integrals

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfelder, R. [Particle Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2014-03-15

    Starting from well-known expressions for the T-matrix and its derivative in standard nonrelativistic potential scattering, I rederive recent path-integral formulations due to Efimov and Barbashov et al. Some new relations follow immediately.

  19. Scattering Theory with Path Integrals

    CERN Document Server

    Rosenfelder, R

    2013-01-01

    Starting from well-known expressions for the $T$-matrix and its derivative in standard nonrelativistic potential scattering I rederive recent path-integral formulations due to Efimov and Barbashov et al. Some new relations follow immediately.

  20. Path Integral for Lattice Staggered Fermions in the Loop Representation

    CERN Document Server

    Aroca, J M; Gambini, R

    1998-01-01

    The path integral formulation in terms of loop variables is introduced for lattice gauge theories with dynamical fermions. The path integral of lattice compact QED with staggered fermions is expressed as a sum over surfaces with border on self-avoiding fermionic paths. Each surface is weighted with a classical action -- written in terms of integer gauge invariant variables -- which gives via transfer matrix method the Hamiltonian of the loop or P-representation. The surfaces correspond to the world sheets of loop-like pure electric flux excitations and meson-like configurations (open electric flux tubes carrying matter fields at their ends). The gauge non-redundancy and the geometric transparency are two appealing features of this description. From the computational point of view, it involves fewer degrees of freedom than the Kogut-Susskind formulation and offers the possibility of alternative numerical methods for dynamical fermions.

  1. Who gives? Multilevel effects of gender and ethnicity on workplace charitable giving.

    Science.gov (United States)

    Leslie, Lisa M; Snyder, Mark; Glomb, Theresa M

    2013-01-01

    Research on diversity in organizations has largely focused on the implications of gender and ethnic differences for performance, to the exclusion of other outcomes. We propose that gender and ethnic differences also have implications for workplace charitable giving, an important aspect of corporate social responsibility. Drawing from social role theory, we hypothesize and find that gender has consistent effects across levels of analysis; women donate more money to workplace charity than do men, and the percentage of women in a work unit is positively related to workplace charity, at least among men. Alternatively and consistent with social exchange theory, we hypothesize and find that ethnicity has opposing effects across levels of analysis; ethnic minorities donate less money to workplace charity than do Whites, but the percentage of minorities in a work unit is positively related to workplace charity, particularly among minorities. The findings provide a novel perspective on the consequences of gender and ethnic diversity in organizations and highlight synergies between organizational efforts to increase diversity and to build a reputation for corporate social responsibility.

  2. Equivariant Localization of Path Integrals

    OpenAIRE

    Szabo, Richard J.

    1996-01-01

    We review equivariant localization techniques for the evaluation of Feynman path integrals. We develop systematic geometric methods for studying the semi-classical properties of phase space path integrals for dynamical systems, emphasizing the relations with integrable and topological quantum field theories. Beginning with a detailed review of the relevant mathematical background -- equivariant cohomology and the Duistermaat-Heckman theorem, we demonstrate how the localization ideas are relat...

  3. Formal language constrained path problems

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C.; Jacob, R.; Marathe, M.

    1997-07-08

    In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

  4. RFID-Based Critical Path Expert System for Agility Manufacture Process Management

    Science.gov (United States)

    Cheng, Haifang; Xiang, Yuli

    This paper presents a critical path expert system for the agility manufacture process management based on radio frequency identification (RFID) technology. The paper explores that the agility manufacture processes can be visible and controllable with RFID. The critical paths or activities can be easily found out and tracked by the RFID tracing technology. And the expert system can optimize the bottle neck of the task process of the agility management with the critical path adjusting and reforming method. Finally, the paper gives a simple application example of the system to discuss how to adjust the critical paths and how to make the process more agility and flexibility with the critical path expert system. With an RFID-based critical path expert system, the agility manufacture process management will be more effective and efficient.

  5. A New Approach to Determine the Critical Path in Stochastic Activity Network

    Directory of Open Access Journals (Sweden)

    Weng-Ming Chu

    2014-01-01

    Full Text Available The determination of the critical path (CP in stochastic networks is difficult. It is partly due to the randomness of path durations and partly due to the probability issue of the selection of the critical path in the network. What we are confronted with is not only the complexity among random variables but also the problem of path dependence of the network. Besides, we found that CP is not necessarily the longest (or shortest path in the network, which was a conventional assumption in use. The Program Evaluation and Review Technique (PERT and Critical Path Index (CPI approaches are not able to deal with this problem efficiently. In this study, we give a new definition on the CP in stochastic network and propose a modified label-correcting tracing algorithm (M-LCTA to solve it. Based on the numerical results, compared with Monte Carlo simulation (MCS, the proposed approach can accurately determine the CP in stochastic networks.

  6. A New Class of Lattice Paths and Partitions with Copies of

    Indian Academy of Sciences (India)

    S Anand; A K Agarwal

    2012-02-01

    Agarwal and Bressoud (Pacific J. Math. 136(2)(1989) 209–228) defined a class of weighted lattice paths and interpreted several -series combinatorially. Using the same class of lattice paths, Agarwal (Utilitas Math. 53(1998) 71–80; ARS Combinatoria 76(2005) 151–160) provided combinatorial interpretations for several more -series. In this paper, a new class of weighted lattice paths, which we call associated lattice paths is introduced. It is shown that these new lattice paths can also be used for giving combinatorial meaning to certain -series. However, the main advantage of our associated lattice paths is that they provide a graphical representation for partitions with + copies of introduced and studied by Agarwal (Partitions with copies of , Lecture Notes in Math., No. 1234 (Berlin/New York: Springer-Verlag) (1985) 1–4) and Agarwal and Andrews (J. Combin. Theory A45(1)(1987) 40–49).

  7. Polymer density functional approach to efficient evaluation of path integrals

    DEFF Research Database (Denmark)

    Brukhno, Andrey; Vorontsov-Velyaminov, Pavel N.; Bohr, Henrik

    2005-01-01

    A polymer density functional theory (P-DFT) has been extended to the case of quantum statistics within the framework of Feynman path integrals. We start with the exact P-DFT formalism for an ideal open chain and adapt its efficient numerical solution to the case of a ring. We show that, similarly......, the path integral problem can, in principle, be solved exactly by making use of the two-particle pair correlation function (2p-PCF) for the ends of an open polymer, half of the original. This way the exact data for one-dimensional quantum harmonic oscillator are reproduced in a wide range of temperatures......-consistent iteration so as to correctly account for the interparticle interactions. The algorithm is speeded up by taking convolutions with the aid of fast Fourier transforms. We apply this approximate path integral DFT (PI-DFT) method to systems within spherical symmetry: 3D harmonic oscillator, atoms of hydrogen...

  8. Multi- Path Routing and Resource Allocation in Active Network

    Institute of Scientific and Technical Information of China (English)

    XU Wu-ping; YAN Pu-liu; WU Ming

    2005-01-01

    An algorithm of traffic distribution called active multi-path routing (AMR) in active network is proposed.AMR adopts multi-path routing and applies nonlinear optimize approximate method to distribute network traffic amongmultiple paths. It is combined to bandwidth resource allocation and the congestion restraint mechanism to avoid congestion happening and worsen. So network performance can be improved greatly. The frame of AMR includes adaptive trafficallocation model, the conception of supply bandwidth and its'allocation model, the principle of congestion restraint and its'model, and the implement of AMR based on multi-agents system in active network. Through simulations, AMR has distinct effects on network performance. The results show AMR is a valid traffic regulation algorithm.

  9. Path Control Experiment of Mobile Robot Based on Supervised Learning

    Directory of Open Access Journals (Sweden)

    Gao Chi

    2013-07-01

    Full Text Available To solve the weak capacity and low control accuracy of the robots which adapt to the complex working conditions, proposed that a path control method based on the driving experience and supervised learning. According to the slope road geometry characteristics, established the modeling study due to ramp pavement path control method and the control structure based on monitoring and self-learning. Made use of the Global Navigation Satellite System did the experiment. The test data illustrates that when the running speed is not greater than 5 m / s, the straight-line trajectory path transverse vertical deviation within 士20cm ,which proved that the control method has a high feasibility. 

  10. Particle production and complex path analysis

    CERN Document Server

    Srinivasan, K

    1999-01-01

    This paper discusses particle production in Schwarzchild-like spacetimes and in an uniform electric field. Both problems are approached using the method of complex path analysis. Particle production in Schwarzchild-like spacetimes with a horizon is obtained here by a new and simple semi-classical method based on the method of complex paths. Hawking radiation is obtained in the (t,r) co-ordinate system of the standard Schwarzchild metric {\\it without} requiring the Kruskal extension. The co-ordinate singularity present at the horizon manifests itself as a singularity in the expression for the semi-classical propagator for a scalar field. We give a prescription whereby this singularity is regularised with Hawking's result being recovered. In the case of the electric field, standard quantum field theoretic methods can be used to obtain particle production in a purely time-dependent gauge. In a purely space-dependent gauge, however, the tunnelling interpretation has to be resorted to. We attempt, in this paper, t...

  11. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  12. What Drives Business Model Adaptation?

    DEFF Research Database (Denmark)

    Saebi, Tina; Lien, Lasse B.; Foss, Nicolai Juul

    2016-01-01

    Business models change as managers not only innovate business models, but also engage in more mundane adaptation in response to external changes, such as changes in the level or composition of demand. However, little is known about what causes such business model adaptation. We employ threat......-rigidity as well as prospect theory to examine business model adaptation in response to external threats and opportunities. Additionally, drawing on the behavioural theory of the firm, we argue that the past strategic orientation of a firm creates path dependencies that influence the propensity of the firm...... to adapt its business model. We test our hypotheses on a sample of 1196 Norwegian companies, and find that firms are more likely to adapt their business model under conditions of perceived threats than opportunities, and that strategic orientation geared towards market development is more conducive...

  13. Path Planning for Search and Rescue Mission using Multicopters

    OpenAIRE

    Andersen, Håvard Lægreid

    2014-01-01

    This thesis considers path planning for a low-cost multicopter used in the searchpart of a search and rescue mission. Search patterns or trajectories are consideredand evaluated through simulations in MATLAB. How to place the onboard camerain order to cover as much area as possible and which altitude that gives the mostarea coverage without making the subjects too small to detect is discussed.The proposed search patterns are implemented in the existing software structureused in this project. ...

  14. Simple Lie algebras arising from Leavitt path algebras

    CERN Document Server

    Abrams, Gene

    2011-01-01

    For a field K and directed graph E, we analyze those elements of the Leavitt path algebra L_K(E) which lie in the commutator subspace [L_K(E), L_K(E)]. This analysis allows us to give easily computable necessary and sufficient conditions to determine which Lie algebras of the form [L_K(E), L_K(E)] are simple, when E is row-finite and L_K(E) is simple.

  15. Optimum Strategies for Selecting Descent Flight-Path Angles

    Science.gov (United States)

    Wu, Minghong G. (Inventor); Green, Steven M. (Inventor)

    2016-01-01

    An information processing system and method for adaptively selecting an aircraft descent flight path for an aircraft, are provided. The system receives flight adaptation parameters, including aircraft flight descent time period, aircraft flight descent airspace region, and aircraft flight descent flyability constraints. The system queries a plurality of flight data sources and retrieves flight information including any of winds and temperatures aloft data, airspace/navigation constraints, airspace traffic demand, and airspace arrival delay model. The system calculates a set of candidate descent profiles, each defined by at least one of a flight path angle and a descent rate, and each including an aggregated total fuel consumption value for the aircraft following a calculated trajectory, and a flyability constraints metric for the calculated trajectory. The system selects a best candidate descent profile having the least fuel consumption value while the fly ability constraints metric remains within aircraft flight descent flyability constraints.

  16. Adaptive radar resource management

    CERN Document Server

    Moo, Peter

    2015-01-01

    Radar Resource Management (RRM) is vital for optimizing the performance of modern phased array radars, which are the primary sensor for aircraft, ships, and land platforms. Adaptive Radar Resource Management gives an introduction to radar resource management (RRM), presenting a clear overview of different approaches and techniques, making it very suitable for radar practitioners and researchers in industry and universities. Coverage includes: RRM's role in optimizing the performance of modern phased array radars The advantages of adaptivity in implementing RRMThe role that modelling and

  17. Verification and Generation of Safe Straight Paths for a 4-DOF Spherical Manipulator

    Directory of Open Access Journals (Sweden)

    Rawand Ehsan J.T.

    2013-04-01

    Full Text Available Sometimes in a manufacturing environment, a robotic arm is wanted to move in a straight path such as welding, painting and assembling. This straight path causes the manipulator to actuate all or most of its joints in the same time to track the path. Along this path, the manipulator may reach a specific singular configuration in its workspace at which one or more joints are in their limits, or a part of the path lies outside the workspace. These conditions make the arm’s movement be unsmooth and may cause damage to the manufacturing process. In this paper, the singularities inside the workspace of a 4-DOF spherical manipulator are indicated and a method is presented for finding the arm configurations (assuming that all joints are actuated at the same time along a straight path between an initial and a goal configurations. All joint limits are presented and if a part of the path lies outside the workspace, the model processes this condition by introducing a new initial configuration through changing the third joint’s (q3 position only. A smooth straight path is generated between any two configurations using the parametric equations of the line connecting them. Unlike the analytical inverse kinematics, which needs a (4 x 4 homogeneous transformations convention matrix (DH to find the joint variables, this method needs only the initial configuration, goal configuration, link lengths and the corresponding Cartesian coordinates of the path. It always gives the correct solution for the under taken path

  18. Discrete Coherent State Path Integrals

    Science.gov (United States)

    Marchioro, Thomas L., II

    1990-01-01

    The quantum theory provides a fundamental understanding of the physical world; however, as the number of degrees of freedom rises, the information required to specify quantum wavefunctions grows geometrically. Because basis set expansions mirror this geometric growth, a strict practical limit on quantum mechanics as a numerical tool arises, specifically, three degrees of freedom or fewer. Recent progress has been made utilizing Feynman's Path Integral formalism to bypass this geometric growth and instead calculate time -dependent correlation functions directly. The solution of the Schrodinger equation is converted into a large dimensional (formally infinite) integration, which can then be attacked with Monte Carlo techniques. To date, work in this area has concentrated on developing sophisticated mathematical algorithms for evaluating the highly oscillatory integrands occurring in Feynman Path Integrals. In an alternative approach, this work demonstrates two formulations of quantum dynamics for which the number of mathematical operations does not scale geometrically. Both methods utilize the Coherent State basis of quantum mechanics. First, a localized coherent state basis set expansion and an approximate short time propagator are developed. Iterations of the short time propagator lead to the full quantum dynamics if the coherent state basis is sufficiently dense along the classical phase space path of the system. Second, the coherent state path integral is examined in detail. For a common class of Hamiltonians, H = p^2/2 + V( x) the path integral is reformulated from a phase space-like expression into one depending on (q,dot q). It is demonstrated that this new path integral expression contains localized damping terms which can serve as a statistical weight for Monte Carlo evaluation of the integral--a process which scales approximately linearly with the number of degrees of freedom. Corrections to the traditional coherent state path integral, inspired by a

  19. Deep Learning Driven Visual Path Prediction from a Single Image.

    Science.gov (United States)

    Huang, Siyu; Li, Xi; Zhang, Zhongfei; He, Zhouzhou; Wu, Fei; Liu, Wei; Tang, Jinhui; Zhuang, Yueting

    2016-09-26

    Capabilities of inference and prediction are significant components of visual systems. Visual path prediction is an important and challenging task among them, with the goal to infer the future path of a visual object in a static scene. This task is complicated as it needs high-level semantic understandings of both the scenes and underlying motion patterns in video sequences. In practice, cluttered situations have also raised higher demands on the effectiveness and robustness of models. Motivated by these observations, we propose a deep learning framework which simultaneously performs deep feature learning for visual representation in conjunction with spatio-temporal context modeling. After that, a unified path planning scheme is proposed to make accurate path prediction based on the analytic results returned by the deep context models. The highly effective visual representation and deep context models ensure that our framework makes a deep semantic understanding of the scenes and motion patterns, consequently improving the performance on visual path prediction task. In experiments, we extensively evaluate the model's performance by constructing two large benchmark datasets from the adaptation of video tracking datasets. The qualitative and quantitative experimental results show that our approach outperforms the state-of-the-art approaches and owns a better generalization capability.

  20. Adaptable positioner; Posicionador adaptativo

    Energy Technology Data Exchange (ETDEWEB)

    Labrador Pavon, I.

    1993-12-31

    This paper describes the circuits and programs in assembly language, developed to control the two DC motors that give mobility to a mechanical arm with two degrees of freedom. As a whole, the system is based in a adaptable regulator designed around a 8 bit microprocessor that, starting from a mode of regulation based in the successive approximation method, evolve to another mode through which, only one approximation is sufficient to get the right position of each motor. (Author) 22 fig. 6 ref.

  1. Adaptive positioner; Posicionador adaptativo

    Energy Technology Data Exchange (ETDEWEB)

    Labrador Pavon, I.

    1993-07-01

    This paper describes the circuits and programs in assembly language, developed to control the two DC motors that give mobility to a mechanical arm with two degrees of freedom. As a whole, the system is based in a adaptable regulator designed around a 8 bit microprocessor that, starting from a mode of regulation based in the successive approximation method, evolve to another mode through which, only one approximation is sufficient to get the right position of each motor. (Author) 6 refs.

  2. New sufficient conditions for Hamiltonian paths.

    Science.gov (United States)

    Rahman, M Sohel; Kaykobad, M; Firoz, Jesun Sahariar

    2014-01-01

    A Hamiltonian path in a graph is a path involving all the vertices of the graph. In this paper, we revisit the famous Hamiltonian path problem and present new sufficient conditions for the existence of a Hamiltonian path in a graph.

  3. Population Monotonic Path Schemes for Simple Games

    NARCIS (Netherlands)

    Ciftci, B.B.; Borm, P.E.M.; Hamers, H.J.M.

    2006-01-01

    A path scheme for a simple game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path.A path scheme is called population monotonic if a player's payoff does not decrease as the pa

  4. Rainbow paths with prescribed ends

    DEFF Research Database (Denmark)

    Alishahi, Meysam; Taherkhani, Ali; Thomassen, Carsten

    2011-01-01

    It was conjectured in [S. Akbari, F. Khaghanpoor, and S. Moazzeni. Colorful paths in vertex coloring of graphs. Preprint] that, if G is a connected graph distinct from C-7, then there is a chi(G)-coloring of G in which every vertex v is an element of V(G) is an initial vertex of a path P with chi......(G) vertices whose colors are different. In[S. Akbari, V. Liaghat, and A. Nikzad. Colorful paths in vertex coloring of graphs. Electron. J. Combin. 18(1):P17, 9pp, 2011] this was proved with left perpendicular chi(G)/2right perpendicular vertices instead of chi(G) vertices. We strengthen this to chi(G) - 1...

  5. Gas-path seal technology

    Science.gov (United States)

    Zuk, J.

    1976-01-01

    Improved gas-path seals are needed for better fuel economy, longer performance retention, and lower maintenance, particularly in advanced, high-performance gas turbine engines. Problems encountered in gas-path sealing are described, as well as new blade-tip sealing approaches for high-pressure compressors and turbines. These include a lubricant coating for conventional, porous-metal, rub-strip materials used in compressors. An improved hot-press metal alloy shows promise to increase the operating surface temperatures of high-pressure-turbine, blade-tip seals to 1450 K (2150 F). Three ceramic seal materials are also described that have the potential to allow much higher gas-path surface operating temperatures than are possible with metal systems.

  6. Innovation paths in wind power

    DEFF Research Database (Denmark)

    Lema, Rasmus; Nordensvärd, Johan; Urban, Frauke

    Denmark and Germany both make substantial investments in low carbon innovation, not least in the wind power sector. These investments in wind energy are driven by the twin objectives of reducing carbon emissions and building up international competitive advantage. Support for wind power dates back...... paths: government policies, demand conditions, geography, value chains, and the strategies undertaken by firms. It demonstrates that the innovation paths common to both countries have roots in a confluence of determining factors which are mainly due to social and political priorities, preferences...... and decisions at national level. However, the sub-trajectories, which create variation between Denmark and Germany, differ in this regard. They tend to have roots in ‘given’ geographical conditions and in company-level technology choices. In other words, many of the similarities in innovation paths between...

  7. Innovative development path of ethnomedicines: the interpretation of the path.

    Science.gov (United States)

    Zhu, Zhaoyun; Fu, Dehuan; Gui, Yali; Cui, Tao; Wang, Jingkun; Wang, Ting; Yang, Zhizhong; Niu, Yanfei; She, Zhennan; Wang, Li

    2017-03-01

    One of the primary purposes of the innovative development of ethnomedicines is to use their excellent safety and significant efficacy to serve a broader population. To achieve this purpose, modern scientific and technological means should be referenced, and relevant national laws and regulations as well as technical guides should be strictly followed to develop standards and to perform systemic research in producing ethnomedicines. Finally, ethnomedicines, which are applied to a limited extent in ethnic areas, can be transformed into safe, effective, and quality-controllable medical products to relieve the pain of more patients. The innovative development path of ethnomedicines includes the following three primary stages: resource study, standardized development research, and industrialization of the achievements and efforts for internationalization. The implementation of this path is always guaranteed by the research and development platform and the talent team. This article is based on the accumulation of long-term practice and is combined with the relevant disciplines, laws and regulations, and technical guidance from the research and development of ethnomedicines. The intention is to perform an in-depth analysis and explanation of the major research thinking, methods, contents, and technical paths involved in all stages of the innovative development path of ethnomedicines to provide useful references for the development of proper ethnomedicine use.

  8. Path Decomposition of Graphs with Given Path Length

    Institute of Scientific and Technical Information of China (English)

    Ming-qing Zhai; Chang-hong Lü

    2006-01-01

    A path decomposition of a graph G is a list of paths such that each edge appears in exactly one path in the list. G is said to admit a {Pl}-decomposition if G can be decomposed into some copies of Pl, where Pl is a path of length ι - 1. Similarly, G is said to admit a {Pl, Pκ}-decomposition if G can be decomposed into some copies of Pl or Pκ. An κ-cycle, denoted by Cκ, is a cycle with κ vertices. An odd tree is a tree of which all vertices have odd degree. In this paper, it is shown that a connected graph G admits a {P3, P4}-decomposition if and only if G is neither a 3-cycle nor an odd tree. This result includes the related result of Yan, Xu and Mutu. Moreover, two polynomial algorithms are given to find {P3}-decomposition and {P3, P4}-decomposition of graphs, respectively. Hence, {P3}-decomposition problem and {P3, P4}-decomposition problem of graphs are solved completely.

  9. Strings, paths, and standard tableaux

    CERN Document Server

    Dasmahapatra, S

    1996-01-01

    For the vacuum sectors of regime-III ABF models, we observe that two sets of combinatorial objects: the strings which parametrize the row-to-row transfer matrix eigenvectors, and the paths which parametrize the corner transfer matrix eigenvectors, can both be expressed in terms of the same set of standard tableaux. Furthermore, the momenta of the strings, the energies of the paths, and the charges of the tableaux are such that there is a weight-preserving bijection between the two sets of eigenvectors, wherein the tableaux play an interpolating role. This bijection is so natural, that we conjecture that it exists in general.

  10. A Pilot Study of Nurses' Experience of Giving Spiritual Care

    Science.gov (United States)

    Deal, Belinda

    2010-01-01

    Using spiritual and religious resources gives patients and families strength to cope during a crisis, but nurses often do not offer spiritual care (Kloosterhouse & Ames, 2002). The purpose of this phenomenological study was to explore nurses" lived experience of giving spiritual care. A descriptive phenomenological approach was used to…

  11. Territorial Entanglements: Ambiguities of Giving Back in Northwestern Laos

    Directory of Open Access Journals (Sweden)

    Michael Benjamin Dwyer

    2014-07-01

    Full Text Available This research note is part of the thematic section, Limits to Giving Back, in the special issue titled “Giving Back in Field Research,” published as Volume 10, Issue 2 in the Journal of Research Practice.

  12. Moving from ‘Giving Back’ to Engagement

    Directory of Open Access Journals (Sweden)

    Gautam Bhan

    2014-07-01

    Full Text Available This research note is part of the thematic section, Giving Back in Solidarity, in the special issue titled “Giving Back in Field Research,” published as Volume 10, Issue 2 in the Journal of Research Practice.

  13. Sources and Uses of Annual Giving at Private Research Universities.

    Science.gov (United States)

    Smith, Christopher L.; Ehrenberg, Ronald G.

    2003-01-01

    Investigated why private research universities differ in the sources and uses of their annual giving using data from 74 private universities and a subset of 29 private universities. Findings identify some factors that determine giving, but models could explain only part of the differences in funding from different sources. (SLD)

  14. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial lighting ceases...

  15. The Conley-Zehnder index for a path of symplectic matrices

    CERN Document Server

    Gutt, Jean

    2012-01-01

    We give here a self contained and elementary introduction to the Conley-Zehnder index for a path of symplectic matrices. We start from the definition of the index as the degree of a map into the circle for a path starting at the identity and ending at a matrix for which 1 is not an eigenvalue. We prove some properties which characterize this index using normal forms for symplectic matrices obtained from geometrical considerations. We explore the relations to Robbin-Salamon index for paths of Lagrangians. We give an axiomatic characterization of the generalization of the Conley-Zehnder index for any continuous path of symplectic matrices defined by Robbin and Salamon.

  16. OPINION GIVING SERVICES AS A SOURCE OF CONSUMER INFORMATION

    Directory of Open Access Journals (Sweden)

    Joanna Wyrwisz

    2015-09-01

    Full Text Available The goal of the article is to determine the place and role of opinion giving services in consumer behaviours. The discussion is conducted around the thesis saying that in the information society, opinion giving services constitute an important source of information for consumers in the process of selecting and purchasing both products and services. In the article the research approach based on the theoretical and empirical examinations was presented. The discussion starts with presenting a defi nition and types of opinion giving services which constitute the base for the characteristics of activities and usefulness of web portals collecting consumers opinions. The use of opinion giving services provided in the purchase process was evaluated. An essential interest in other consumers opinions, placed in Internet, was observed together with perceiving them as credible. Positive assessment of the functionality of opinion giving services was noticed.

  17. Career Paths in Environmental Sciences

    Science.gov (United States)

    Career paths, current and future, in the environmental sciences will be discussed, based on experiences and observations during the author's 40 + years in the field. An emphasis will be placed on the need for integrated, transdisciplinary systems thinking approaches toward achie...

  18. Geodesic flows on path spaces

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the path space over a compact Riemannian manifold, the global existence and the global uniqueness of the quasi-invariant geodesic flows with respect to a negative Markov connection are obtained in this paper. The results answer affirmatively a left problem of Li.

  19. Methodologies for tracking learning paths

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth; Gilje, Øystein; Lindstrand, Fredrik

    2009-01-01

    The article concerns the design of a collaborative research project (2008-09) entitled Making a Filmmaker, which examines how young Scandinavian filmmakers create their own learn- ing paths in formal and/or informal contexts. Our interest is how learning experiences and contexts motivate the young...

  20. On the path to differentiation

    DEFF Research Database (Denmark)

    Martinsen, Dorte Sindbjerg; Uygur, Ayca

    2014-01-01

    by examining the ‘path to differentiation’ within EU working time regulation as it has unfolded over time. It identifies the ‘opt-out’ as a means of differentiation adopted to overcome policy deadlocks within collective decision-making, albeit one with unforeseen consequences. In particular, the contribution...

  1. Determinants of weighted path matrices

    CERN Document Server

    Talaska, Kelli

    2012-01-01

    We find rational expressions for all minors of the weighted path matrix of a directed graph, generalizing the classical Lindstrom/Gessel-Viennot result for acyclic directed graphs. The formulas are given in terms of certain flows in the graph.

  2. Engineering an adaptive and socially- aware feedback acquisition.

    OpenAIRE

    Almaliki, Malik Rajab

    2015-01-01

    Self-adaptive software systems are characterised by their ability to monitor changes in their dynamic environment and react to these changes when needed. Adaptation is driven by these changes in the internal state of the system and its external environment. Social Adaptation is a kind of adaptation which gives users’ feedback a primary role in shaping adaptation decisions. Social Adaptation infers and employs users’ collective judgement on the alternative behaviours of a system as the main dr...

  3. Optimal paths as correlated random walks

    Science.gov (United States)

    Perlsman, E.; Havlin, S.

    2006-01-01

    A numerical study of optimal paths in the directed polymer model shows that the paths are similar to correlated random walks. It is shown that when a directed optimal path of length t is divided into 3 segments whose length is t/3, the correlation between the transversal movements along the first and last path segments is independent of the path length t. It is also shown that the transversal correlations along optimal paths decrease as the paths approach their endpoints. The numerical results obtained for optimal paths in 1+4 dimensions are qualitatively similar to those obtained for optimal paths in lower dimensions, and the data supplies a strong numerical indication that 1+4 is not the upper critical dimension of this model, and of the associated KPZ equation.

  4. On the importance of path for phase unwrapping in synthetic aperture radar interferometry.

    Science.gov (United States)

    Osmanoglu, Batuhan; Dixon, Timothy H; Wdowinski, Shimon; Cabral-Cano, Enrique

    2011-07-01

    Phase unwrapping is a key procedure in interferometric synthetic aperture radar studies, translating ambiguous phase observations to topography, and surface deformation estimates. Some unwrapping algorithms are conducted along specific paths based on different selection criteria. In this study, we analyze six unwrapping paths: line scan, maximum coherence, phase derivative variance, phase derivative variance with branch-cut, second-derivative reliability, and the Fisher distance. The latter is a new path algorithm based on Fisher information theory, which combines the phase derivative with the expected variance to get a more robust path, potentially performing better than others in the case of low image quality. In order to compare only the performance of the paths, the same unwrapping function (phase derivative integral) is used. Results indicate that the Fisher distance algorithm gives better results in most cases.

  5. Scan path entropy and Arrow plots: Capturing scanning behavior of multiple observers

    Directory of Open Access Journals (Sweden)

    Ignace T C Hooge

    2013-12-01

    Full Text Available Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures 1 scan path entropy to quantify gaze guidance and 2 the arrow plot to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50. The new measures were tested in an eye tracking study (48 observers, 39 advertisements. Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place.

  6. Multi-Objective and Multi-Constrained Non-Additive Shortest Path Problems

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander; Pisinger, David

    of this paper is to give a general framework for dominance tests for problems involving a number of non-additive criteria. These dominance tests can help eliminate paths in a dynamic programming framework when using multiple objectives. Results on real-life multi-objective problems containing non......Shortest path problems appear as subproblems in numerous optimization problems. In most papers concerning multiple objective shortest path problems, additivity of the objective is a de-facto assumption, but in many real-life situations objectives and criteria, can be non-additive. The purpose...

  7. Multi-Objective and Multi-Constrained Non-Additive Shortest Path Problems

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander; Pisinger, David

    2011-01-01

    of this paper is to give a general framework for dominance tests for problems involving a number of non-additive criteria. These dominance tests can help to eliminate paths in a dynamic programming framework when using multiple objectives. Results on real-life multi-objective problems containing non......Shortest path problems appear as subproblems in numerous optimization problems. In most papers concerning multiple objective shortest path problems, additivity of the objective is a de-facto assumption, but in many real-life situations objectives and criteria, can be non-additive. The purpose...

  8. CURVILINEAR PATHS AND TRUST REGION METHODS WITH NONMONOTONIC BACK TRACKING TECHNIQUE FOR UNCONSTRAINED OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    De-tong Zhu

    2001-01-01

    In this paper we modify type approximate trust region methods via two curvilinear paths for unconstrained optimization. A mixed strategy using both trust region and line search techniques is adopted which switches to back tracking steps when a trial step produced by the trust region subproblem is unacceptable. We give a series of properties of both optimal path and modified gradient path. The global convergence and fast local convergence rate of the proposed algorithms are established under some reasonable conditions. A nonmonotonic criterion is used to speed up the convergence progress in some ill-conditioned cases.

  9. Intelligent PID guidance control for AUV path tracking

    Institute of Scientific and Technical Information of China (English)

    李晔; 姜言清; 王磊峰; 曹建; 张国成

    2015-01-01

    Based on rational behavior model of three layers, a tracking control system is designed for straight line tracking which is commonly used in underwater survey missions. An intelligent PID control law implemented as planning level during the control system using transverse deviation is came up with. Continuous tracking of path expressed by a point sequence can be realized by the law. Firstly, a path tracking control system based on rational behavior model of three layers is designed, mainly satisfying the needs of underactuated AUV. Since there is no need to perform spatially coupled maneuvers, the 3D path tracking control is decoupled into planar 2D path tracking and depth or height tracking separately. Secondly, planar path tracking controller is introduced. For the reason that more attention is paid to comparing with vertical position control, transverse deviation in analytical form is derived. According to the Lyapunov direct theory, control law is designed using discrete PID algorithm whose parameters obey adaptive fuzzy adjustment. Reference heading angle is given as an output of the guidance controller conducted by lateral deviation together with its derivative. For the purpose of improving control quality and facilitating parameter modifying, data normalize modules based on Sigmoid function are applied to input-output data manipulation. Lastly, a sequence of experiments was carried out successfully, including tests in Longfeng lake and at the Yellow sea. In most challenging sea conditions, tracking errors of straight line are below 2 m in general. The results show that AUV is able to compensate the disturbance brought by sea current. The provided test results demonstrate that the designed guidance controller guarantees stably and accurately straight route tracking. Besides, the proposed control system is accessible for continuous comb-shaped path tracking in region searching.

  10. ADAPT Dataset

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Diagnostics and Prognostics Testbed (ADAPT) Project Lead: Scott Poll Subject Fault diagnosis in electrical power systems Description The Advanced...

  11. Who, Who, Who Gives a Hoot about Bones?

    Science.gov (United States)

    Dolan, Arthur

    1988-01-01

    Describes a mouse skeleton reconstruction activity from owl pellets. Gives information about the materials, directions for students, and a five-day unit schedule. Provides some owl pellet sources. (YP)

  12. Giving the Gift of Life at the End of Life

    Science.gov (United States)

    ... About AOA Contact Us A A A Advancing the distinctive philosophy and practice of osteopathic medicine Inside ... Manipulative Treatment Becoming a DO Video Library Giving the Gift of Life at the End of Life ...

  13. Astronaut Twins Give Clues to Health Hazards of Spaceflight

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163391.html Astronaut Twins Give Clues to Health Hazards of Spaceflight NASA ... aboard the International Space Station, and his identical twin Mark, a retired astronaut. Mark remained on Earth ...

  14. Did El Nino Weather Give Zika a Boost?

    Science.gov (United States)

    ... fullstory_162611.html Did El Nino Weather Give Zika a Boost? Climate phenomenon could have helped infection- ... might have aided the explosive spread of the Zika virus throughout South America, a new study reports. ...

  15. Reciprocity revisited: Give and take in Dutch and immigrant families

    NARCIS (Netherlands)

    A. Komter; J.M.D. Schans

    2008-01-01

    Classical theory suggests that "generalized reciprocity," giving without clear expectations of returns, is characteristic for exchange within the family. Modern theory assumes differences between Western, "individualistic" cultures, and non-Western, more "collectivistic" cultures, presumably leading

  16. "To All Stroke Survivors - Never, Ever Give Up"

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Stroke Rehabilitation "To All Stroke Survivors – Never, Ever Give Up." Past Issues / Spring ... have for other Americans who are recovering from strokes and other serious health challenges? What about their ...

  17. We should give love to whoever needs without hesitation

    Institute of Scientific and Technical Information of China (English)

    杨彩荣

    2010-01-01

    @@ The text Fog tells us a touching story, in which an old blind man helped a girl out of a thick fog by his unique sense of touch. From the text, we know the girl has never helped the old man, or even she doesn't know him. But he helped her! What's more, he thinks the fog gives him a chance to pay back the help that 'people give to him when it's sunny" .

  18. An Application of Multi-Criteria Shortest Path to a Customizable Hex-Map Environment

    Science.gov (United States)

    2015-03-26

    the precursor to the PathFinder model, was built in 2014 and incorporates the rules and historical information inherent to the war game “Drive on...Metz.” While the Metz model reflects the same details and specifications of the original game , the PathFinder model expands the application of the model...applicable to the war- game , “Drive on Metz,” but is not relevant outside this domain. The PathFinder model has potential for adaptation to other hex

  19. Facilitating Description and Selection of Learning Paths: the learning path specification put to the test

    NARCIS (Netherlands)

    Janssen, José

    2008-01-01

    Jansen, J. (2008). Facilitating Description and Selection of Learning Paths: the learning path specification put to the test. Presentation at the Otec Colloquium. April, 2008, Heerlen, The Netherlands.

  20. Enzymatic minimum free energy path calculations using swarms of trajectories.

    Science.gov (United States)

    Sanchez-Martinez, Melchor; Field, Martin; Crehuet, Ramon

    2015-01-22

    The development of approaches for simulating rare events in complex molecular systems is a central concern in chemical physics. In recent work, Roux and co-workers proposed a novel, swarms of trajectories (SoT) method for determining the transition paths of such events. It consists of the dynamical refinement on the system's free energy surface of a putative transition path that is parametrized in terms of a set of collective variables (CVs) that are identified as being important for the transition. In this work, we have implemented the SoT method and used it to investigate the catalytic mechanisms of two enzymatic reactions using hybrid QM/MM potentials. Our aim has been to test the performance of SoT for enzyme systems and to devise robust simulation protocols that can be employed in future studies of this type. We identify the conditions under which converged results can be obtained using inertial and Brownian dynamical evolutions of the CVs, show that the inclusion of several CVs can give significant additional insight into the mechanisms of the reactions, and show that the use of minimum energy paths as starting guesses can greatly accelerate path refinement.

  1. Survey on path and cycle embedding in some networks

    Institute of Scientific and Technical Information of China (English)

    Jun-Ming XU; Meijie MA

    2009-01-01

    To find a cycle (resp. path) of a given length in a graph is the cycle (resp. path) embedding problem. To find cycles of all lengths from its girth to its order in a graph is the pancyclic problem. A stronger concept than the pancylicity is the panconnectivity. A graph of order n is said tobe panconnected if for any pair of different vertices x and y with distance d there exist xy-paths of every length from of to n. The pancyclicity or the panconnectivity is an important property to determine if the topology of a network is suitable for some applications where mapping cycles or paths of any length into the topology of the network is required. The pancyclicity and the panconnectivity of interconnection networks have attracted much research interest in recent years. A large amount of related work appeared in the literature, with some repetitions. The purpose of this paper is to give a survey of the results related to these topics for the hypercube and somehypercube-like networks.

  2. Path modeling and process control

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar; Rodionova, O.; Pomerantsev, A.

    2007-01-01

    and having three or more stages. The methods are applied to a process control of a multi-stage production process having 25 variables and one output variable. When moving along the process, variables change their roles. It is shown how the methods of path modeling can be applied to estimate variables...... be performed regarding the foreseeable output property y, and with respect to an admissible range of correcting actions for the parameters of the next stage. In this paper the basic principles of path modeling is presented. The mathematics is presented for processes having only one stage, having two stages...... of the next stage with the purpose of obtaining optimal or almost optimal quality of the output variable. An important aspect of the methods presented is the possibility of extensive graphic analysis of data that can provide the engineer with a detailed view of the multi-variate variation in data....

  3. Shortest Paths With Side Sensors

    CERN Document Server

    Salaris, Paolo; Bicchi, Antonio

    2011-01-01

    We present a complete characterization of shortest paths to a goal position for a vehicle with unicycle kinematics and a limited range sensor, constantly keeping a given landmark in sight. Previous work on this subject studied the optimal paths in case of a frontal, symmetrically limited Field--Of--View (FOV). In this paper we provide a generalization to the case of arbitrary FOVs, including the case that the direction of motion is not an axis of symmetry for the FOV, and even that it is not contained in the FOV. The provided solution is of particular relevance to applications using side-scanning, such as e.g. in underwater sonar-based surveying and navigation.

  4. Information about a layperson's knowledge supports experts in giving effective and efficient online advice to laypersons.

    Science.gov (United States)

    Nückles, Matthias; Wittwer, Jörg; Renkl, Alexander

    2005-12-01

    To give effective and efficient advice to laypersons, experts should adapt their explanations to the layperson's knowledge. However, experts often fail to consider the limited domain knowledge of laypersons. To support adaptation in asynchronous helpdesk communication, researchers provided computer experts with information about a layperson's knowledge. A dialogue experiment (N = 80 dyads of experts and laypersons) was conducted that varied the displayed information. Rather than sensitizing the experts to generally improve the intelligibility of their explanations, the individuating information about the layperson enabled them to make specific partner adjustments that increased the effectiveness and efficiency of the communication. The results are suggestive of ways in which the provision of instructional explanations could be enhanced in Internet-based communication.

  5. The path of code linting

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Join the path of code linting and discover how it can help you reach higher levels of programming enlightenment. Today we will cover how to embrace code linters to offload cognitive strain on preserving style standards in your code base as well as avoiding error-prone constructs. Additionally, I will show you the journey ahead for integrating several code linters in the programming tools your already use with very little effort.

  6. Levy Flights over Quantum Paths

    CERN Document Server

    Laskin, N

    2005-01-01

    An impact of integration over the paths of the Levy flights on the quantum mechanical kernel has been studied. Analytical expression for a free particle kernel has been obtained in terms of the Fox H-function. A new equation for the kernel of a partical in the box has been found. New general results include the well known quantum formulae for a free particle kernel and particle in box kernel.

  7. AFM's path to atomic resolution

    OpenAIRE

    2005-01-01

    We review progress in improving the spatial resolution of atomic force microscopy (AFM) under vacuum. After an introduction to the basic imaging principle and a conceptual comparison to scanning tunneling microscopy (STM), we outline the main challenges of AFM as well as the solutions that have evolved in the first 20 years of its existence. Some crucial steps along AFM's path toward higher resolution are discussed, followed by an outlook on current and future applications.

  8. Path planning under spatial uncertainty.

    Science.gov (United States)

    Wiener, Jan M; Lafon, Matthieu; Berthoz, Alain

    2008-04-01

    In this article, we present experiments studying path planning under spatial uncertainties. In the main experiment, the participants' task was to navigate the shortest possible path to find an object hidden in one of four places and to bring it to the final destination. The probability of finding the object (probability matrix) was different for each of the four places and varied between conditions. Givensuch uncertainties about the object's location, planning a single path is not sufficient. Participants had to generate multiple consecutive plans (metaplans)--for example: If the object is found in A, proceed to the destination; if the object is not found, proceed to B; and so on. The optimal solution depends on the specific probability matrix. In each condition, participants learned a different probability matrix and were then asked to report the optimal metaplan. Results demonstrate effective integration of the probabilistic information about the object's location during planning. We present a hierarchical planning scheme that could account for participants' behavior, as well as for systematic errors and differences between conditions.

  9. Time optimal paths for high speed maneuvering

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  10. Spreading paths in partially observed social networks

    CERN Document Server

    Onnela, Jukka-Pekka

    2011-01-01

    Understanding how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading path lengths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, structurally realistic social network as a platform for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Alt...

  11. Path-based Queries on Trajectory Data

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

    2014-01-01

    a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set....... To efficiently support strict path queries, we present a novel NETwork-constrained TRAjectory index (NETTRA). This index enables very efficient retrieval of trajectories that follow a specific path, i.e., strict path queries. NETTRA uses a new path encoding scheme that can determine if a trajectory follows......, consisting of 1.7 million trajectories (941 million GPS records) and a road network with 1.3 million edges, shows a speed-up of two orders of magnitude compared to state-of-the-art trajectory indexes....

  12. Walking paths to and from a goal differ: on the role of bearing angle in the formation of human locomotion paths.

    Directory of Open Access Journals (Sweden)

    Manish Sreenivasa

    Full Text Available The path that humans take while walking to a goal is the result of a cognitive process modulated by the perception of the environment and physiological constraints. The path shape and timing implicitly embeds aspects of the architecture behind this process. Here, locomotion paths were investigated during a simple task of walking to and from a goal, by looking at the evolution of the position of the human on a horizontal (x,y plane. We found that the path while walking to a goal was not the same as that while returning from it. Forward-return paths were systematically separated by 0.5-1.9m, or about 5% of the goal distance. We show that this path separation occurs as a consequence of anticipating the desired body orientation at the goal while keeping the target in view. The magnitude of this separation was strongly influenced by the bearing angle (difference between body orientation and angle to goal and the final orientation imposed at the goal. This phenomenon highlights the impact of a trade-off between a directional perceptual apparatus-eyes in the head on the shoulders-and and physiological limitations, in the formation of human locomotion paths. Our results give an insight into the influence of environmental and perceptual variables on human locomotion and provide a basis for further mathematical study of these mechanisms.

  13. What drives the gender gap in charitable giving? Lower empathy leads men to give less to poverty relief.

    Science.gov (United States)

    Willer, Robb; Wimer, Christopher; Owens, Lindsay A

    2015-07-01

    We draw upon past research on gender and prosocial emotions in hypothesizing that empathy can help explain the gender gap in charitable giving. In a nationally representative survey, we found that men reported less willingness to give money or volunteer time to a poverty relief organization, gaps that were mediated by men's lower reported feelings of empathy toward others. We also experimentally tested how effective a variety of different ways of framing poverty relief were for promoting giving. Framing poverty as an issue that negatively affects all Americans increased men's willingness to donate to the cause, eliminating the gender gap. Mediation analysis revealed that this "aligned self-interest" framing worked by increasing men's reported poverty concern, not by changing their understanding of the causes of poverty. Thus, while men were generally less motivated by empathy, they responded to a framing that recast charitable giving as consistent with their self-interest. Exposure to the same framing, however, led women to report lower willingness to volunteer time for poverty relief, suggesting that framing giving as consistent with self-interest may discourage those who give because of an empathic response to poverty.

  14. Multiple Paths to Encephalization and Technical Civilizations

    Science.gov (United States)

    Schwartzman, David; Middendorf, George

    2011-12-01

    We propose consideration of at least two possible evolutionary paths for the emergence of intelligent life with the potential for technical civilization. The first is the path via encephalization of homeothermic animals; the second is the path to swarm intelligence of so-called superorganisms, in particular the social insects. The path to each appears to be facilitated by environmental change: homeothermic animals by decreased climatic temperature and for swarm intelligence by increased oxygen levels.

  15. Path-Based Supports for Hypergraphs

    Science.gov (United States)

    Brandes, Ulrik; Cornelsen, Sabine; Pampel, Barbara; Sallaberry, Arnaud

    A path-based support of a hypergraph H is a graph with the same vertex set as H in which each hyperedge induces a Hamiltonian subgraph. While it is NP-complete to compute a path-based support with the minimum number of edges or to decide whether there is a planar path-based support, we show that a path-based tree support can be computed in polynomial time if it exists.

  16. Multiresolution Path Planning for Mobile Robots,

    Science.gov (United States)

    1985-05-01

    8217U’ MULTIRESOLUTION PATH PLANNING * . FOR MOBILE ROBOTS I Subbarao Kambhampati * -- Larry S. Davis Computer Vision Laboratory * Center for Automation...COUWEPARK MARVUM EP Vo Is- .. . .. CAR-TR-127 DAAK70-83-K--0018 CS-TR-1507 MAY 1085 MULTIRESOLUTION PATH PLANNING FOR MOBILE ROBOTS Subbarao Kambhampati...planning is central to mobile * robot applications. Path planning for mobile robots is in many ways different * from the more familiar case of path

  17. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance, The world model is represented as the knowledge data and stored in the knowledge base with rules. The expert system can find a collision-avoidance path . Otherwise, it shows the collision secton in which the moved object is blocked . Several examples for the different objects to pass throngli the different channels and to find a collision-free path have been testnd. The simulating resuks of the planner give out the planning sequence or blocked section(s) . The output information is useful for making decision of the robot motion and modifying the technological parameters of the world .

  18. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance,The world model is represented as the knowledge data and stored in the knowledge base with rules.The expert system can find a collision-avoidance path.Otherwise.it shows the collision secton in which the moved object is blocked,Several examples for the different objects to pass through the different channels and to find a collision-free path have been tested.The simulating results of the palnner give out the planning sequence or blocked section(s).The output information is useful for making decision of the robot motion and modifyting the technological parameters of the world.

  19. Reachability by paths of bounded curvature in a convex polygon

    KAUST Repository

    Ahn, Heekap

    2012-01-01

    Let B be a point robot moving in the plane, whose path is constrained to forward motions with curvature at most 1, and let P be a convex polygon with n vertices. Given a starting configuration (a location and a direction of travel) for B inside P, we characterize the region of all points of P that can be reached by B, and show that it has complexity O(n). We give an O(n2) time algorithm to compute this region. We show that a point is reachable only if it can be reached by a path of type CCSCS, where C denotes a unit circle arc and S denotes a line segment. © 2011 Elsevier B.V.

  20. A discrete history of the Lorentzian path integral

    CERN Document Server

    Loll, R

    2003-01-01

    In these lecture notes, I describe the motivation behind a recent formulation of a non-perturbative gravitational path integral for Lorentzian (instead of the usual Euclidean) space-times, and give a pedagogical introduction to its main features. At the regularized, discrete level this approach solves the problems of (i) having a well-defined Wick rotation, (ii) possessing a coordinate-invariant cutoff, and (iii) leading to_convergent_ sums over geometries. Although little is known as yet about the existence and nature of an underlying continuum theory of quantum gravity in four dimensions, there are already a number of beautiful results in d=2 and d=3 where continuum limits have been found. They include an explicit example of the inequivalence of the Euclidean and Lorentzian path integrals, a non-perturbative mechanism for the cancellation of the conformal factor, and the discovery that causality can act as an effective regulator of quantum geometry.

  1. Hierarchical path planning and control of a small fixed-wing UAV: Theory and experimental validation

    Science.gov (United States)

    Jung, Dongwon

    2007-12-01

    problem is formulated by setting up geometric linear constraints as well as boundary conditions. Subsequently, we construct B-spline path templates by solving a set of distinct optimization problems. For application in UAV motion planning, the path templates are incorporated to replace parts of the entire path by the smooth B-spline paths. Each path segment is stitched together while preserving continuity to obtain a final smooth reference path to be used for path following control. The path following control for a small fixed-wing UAV to track the prescribed smooth reference path is also addressed. Assuming the UAV is equipped with an autopilot for low level control, we adopt a kinematic error model with respect to the moving Serret-Frenet frame attached to a path for tracking controller design. A kinematic path following control law that commands heading rate is presented. Backstepping is applied to derive the roll angle command by taking into account the approximate closed-loop roll dynamics. A parameter adaptation technique is employed to account for the inaccurate time constant of the closed-loop roll dynamics during actual implementation. Finally, we implement the proposed hierarchical path control of a small UAV on the actual hardware platform, which is based on an 1/5 scale R/C model airframe (Decathlon) and the autopilot hardware and software. Based on the hardware-in-the-loop (HIL) simulation environment, the proposed hierarchical path control algorithm has been validated through on-line, real-time implementation on a small micro-controller. By a seamless integration of the control algorithms for path planning, path smoothing, and path following, it has been demonstrated that the UAV equipped with a small autopilot having limited computational resources manages to accomplish the path control objective to reach the goal while avoiding obstacles with minimal human intervention.

  2. Infants' online perception of give-and-take interactions.

    Science.gov (United States)

    Elsner, Claudia; Bakker, Marta; Rohlfing, Katharina; Gredebäck, Gustaf

    2014-10-01

    This research investigated infants' online perception of give-me gestures during observation of a social interaction. In the first experiment, goal-directed eye movements of 12-month-olds were recorded as they observed a give-and-take interaction in which an object is passed from one individual to another. Infants' gaze shifts from the passing hand to the receiving hand were significantly faster when the receiving hand formed a give-me gesture relative to when it was presented as an inverted hand shape. Experiment 2 revealed that infants' goal-directed gaze shifts were not based on different affordances of the two receiving hands. Two additional control experiments further demonstrated that differences in infants' online gaze behavior were not mediated by an attentional preference for the give-me gesture. Together, our findings provide evidence that properties of social action goals influence infants' online gaze during action observation. The current studies demonstrate that infants have expectations about well-formed object transfer actions between social agents. We suggest that 12-month-olds are sensitive to social goals within the context of give-and-take interactions while observing from a third-party perspective.

  3. The diagnostic path, a useful visualisation tool in virtual microscopy

    Directory of Open Access Journals (Sweden)

    Hufnagl Peter

    2006-11-01

    Full Text Available Abstract Background The Virtual Microscopy based on completely digitalised histological slide. Concerning this digitalisation many new features in mircoscopy can be processed by the computer. New applications are possible or old, well known techniques of image analyses can be adapted for routine use. Aims A so called diagnostic path observes in the way of a professional sees through a histological virtual slide combined with the text information of the dictation process. This feature can be used for image retrieval, quality assurance or for educational purpose. Materials and methods The diagnostic path implements a metadata structure of image information. It stores and processes the different images seen by a pathologist during his "slide viewing" and the obtained image sequence ("observation path". Contemporary, the structural details of the pathology reports were analysed. The results were transferred into an XML structure. Based on this structure, a report editor and a search function were implemented. The report editor compiles the "diagnostic path", which is the connection from the image viewing sequence ("observation path" and the oral report sequence of the findings ("dictation path". The time set ups of speech and image viewing serve for the link between the two sequences. The search tool uses the obtained diagnostic path. It allows the user to search for particular histological hallmarks in pathology reports and in the corresponding images. Results The new algorithm was tested on 50 pathology reports and 74 attached histological images. The creation of a new individual diagnostic path is automatically performed during the routine diagnostic process. The test prototype experienced an insignificant prolongation of the diagnosis procedure (oral case description and stated diagnosis by the pathologist and a fast and reliable retrieval, especially useful for continuous education and quality control of case description and diagnostic work

  4. Characterizing path graphs by forbidden induced subgraphs

    CERN Document Server

    Lévêque, Benjamin; Preissmann, Myriam

    2008-01-01

    A graph is a path graph if it is the intersection graph of a family of subpaths of a tree. In 1970, Renz asked for a characterizaton of path graph by forbidden induced subgraphs. Here we answer this question by listing all graphs that are not path graphs and are minimal with this property.

  5. Partial Path Column Generation for the ESPPRC

    DEFF Research Database (Denmark)

    Jepsen, Mads Kehlet; Petersen, Bjørn

    This talk introduces a decomposition of the Elementary Shortest Path Problem with Resource Constraints(ESPPRC), where the path is combined by smaller sub paths. We show computational result by comparing different approaches for the decomposition and compare the best of these with existing...

  6. Multi-level Indoor Path Planning Method

    NARCIS (Netherlands)

    Xiong, Q.; Zhu, Q.; Zlatanova, S.; Du, Z.; Zhang, Y.; Zeng, L.

    2015-01-01

    Indoor navigation is increasingly widespread in complex indoor environments, and indoor path planning is the most important part of indoor navigation. Path planning generally refers to finding the most suitable path connecting two locations, while avoiding collision with obstacles. However, it is a

  7. A SCALED CENTRAL PATH FOR LINEAR PROGRAMMING

    Institute of Scientific and Technical Information of China (English)

    Ya-xiang Yuan

    2001-01-01

    Interior point methods are very efficient methods for solving large scale linear programming problems. The central path plays a very important role in interior point methods. In this paper we propose a new central path, which scales the variables. Thus it has the advantage of forcing the path to have roughly the same distance from each active constraint boundary near the solution.

  8. Symbolic PathFinder v7

    DEFF Research Database (Denmark)

    Luckow, Kasper Søe; Păsăreanu, Corina

    2014-01-01

    We describe Symbolic PathFinder v7 in terms of its updated design addressing the changes of Java PathFinder v7 and of its new optimization when computing path conditions. Furthermore, we describe the Symbolic Execution Tree Extension; a newly added feature that allows for outputting the symbolic ...

  9. PERFORMANCE ANALYSIS OF MULTI-PATH TCP NETWORK

    Directory of Open Access Journals (Sweden)

    Hamzah M A Hijawi

    2016-03-01

    Full Text Available MPTCP is proposed by IETF working group, it allows a single TCP stream to be split across multiple paths. It has obvious benefits in performance and reliability. MPTCP has implemented in Linux-based distributions that can be compiled and installed to be used for both real and experimental scenarios. In this article, we provide performance analyses for MPTCP with a laptop connected to WiFi access point and 3G cellular network at the same time. We prove experimentally that MPTCP outperforms regular TCP for WiFi or 3G interfaces. We also compare four types of congestion control algorithms for MPTCP that are also implemented in the Linux Kernel. Results show that Alias Linked Increase Congestion Control algorithm outperforms the others in the normal traffic load while Balanced Linked Adaptation algorithm outperforms the rest when the paths are shared with heavy traffic, which is not supported by MPTCP.

  10. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2016-01-01

    Graduate students who want to become familiar with advanced computational strategies in classical and quantum dynamics will find here both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name a few. Well-chosen and detailed examples illustrate the perturbation theory, canonical transformations, the action principle and demonstrate the usage of path integrals. This new edition has been revised and enlarged with chapters on quantum electrodynamics, high energy physics, Green’s functions and strong interaction.

  11. Collective Philanthropy: Describing and Modeling the Ecology of Giving

    CERN Document Server

    Gottesman, William L; Dodds, Peter Sheridan

    2013-01-01

    Reflective of income and wealth distributions, philanthropic gifting appears to follow an approximate power-law size distribution as measured by the size of gifts received by individual institutions. We explore the ecology of gifting by analysing data sets of individual gifts for a diverse group of institutions dedicated to education, medicine, art, public support, and religion. We find that the detailed forms of gift-size distributions differ across but are relatively constant within charity categories. We construct a model for how a donor's income affects their giving preferences in different charity categories, offering a mechanistic explanation for variations in institutional gift-size distributions. We discuss how knowledge of gift-sized distributions may be used to assess an institution's gift-giving profile, to help set fundraising goals, and to design an institution-specific giving pyramid.

  12. VFI-based Robotic Arm Control for Natural Adaptive Motion

    Directory of Open Access Journals (Sweden)

    Woosung Yang

    2014-03-01

    Full Text Available Since neural oscillator based control methods can generate rhythmic motion without information on system dynamics, they can be a promising alternative to traditional motion planning based control approaches. However, for field application, they still need to be robust against unexpected forces or changes in environments so as to be able to generate “natural motion” like most biological systems. In this study a biologically inspired control algorithm that combines neural oscillators and virtual force is proposed. This work gives the condition with respect to parameters tuning to stably activate the neural oscillators. This is helpful to achieve motion adaptability to environmental changes keeping the motion repeatability. He efficacy and efficiency of the proposed methods are tested in the control of a planar three-linkage robotic arm. It is shown that the proposed controller generates a given circular path stably and repeatedly, even with unexpected contact with a wall. The adaptivity of motion control is also tested in control of a robotic arm with redundant degrees of freedom. The proposed control algorithm works throughout the simulations and experiments.

  13. Gift-giving in the medical student--patient relationship.

    Science.gov (United States)

    Alamri, Yassar Abdullah S

    2012-08-01

    There is paucity in the published literature that provides any ethical guidance guiding gift-giving within the student--patient relationship. This is perhaps because the dynamics of the medical student--patient relationship have not yet been explored as extensively as the doctor--patient relationship. More importantly, however, gift--giving in the doctor-patient relationship has traditionally been from the patient to the doctor and not vice versa. This article examines the literature published in this vicinity reflecting on an encounter with a patient.

  14. Consistent mutational paths predict eukaryotic thermostability

    Directory of Open Access Journals (Sweden)

    van Noort Vera

    2013-01-01

    Full Text Available Abstract Background Proteomes of thermophilic prokaryotes have been instrumental in structural biology and successfully exploited in biotechnology, however many proteins required for eukaryotic cell function are absent from bacteria or archaea. With Chaetomium thermophilum, Thielavia terrestris and Thielavia heterothallica three genome sequences of thermophilic eukaryotes have been published. Results Studying the genomes and proteomes of these thermophilic fungi, we found common strategies of thermal adaptation across the different kingdoms of Life, including amino acid biases and a reduced genome size. A phylogenetics-guided comparison of thermophilic proteomes with those of other, mesophilic Sordariomycetes revealed consistent amino acid substitutions associated to thermophily that were also present in an independent lineage of thermophilic fungi. The most consistent pattern is the substitution of lysine by arginine, which we could find in almost all lineages but has not been extensively used in protein stability engineering. By exploiting mutational paths towards the thermophiles, we could predict particular amino acid residues in individual proteins that contribute to thermostability and validated some of them experimentally. By determining the three-dimensional structure of an exemplar protein from C. thermophilum (Arx1, we could also characterise the molecular consequences of some of these mutations. Conclusions The comparative analysis of these three genomes not only enhances our understanding of the evolution of thermophily, but also provides new ways to engineer protein stability.

  15. A Path to Collaborative Strategic Learning

    Energy Technology Data Exchange (ETDEWEB)

    Nancy M. Carlson

    2003-10-01

    Collaborative learning is critical for the future of any organization and must align with the strategic organizational processes that result in products valued by others. To discover these processes, proposal preparation is explored using topic-oriented ethnography, grounded theory, and an innovative addition to qualitative interviewing, called metainquiry. Using interview data from editors, graphic artists, text processors, scientists, engineers, and technical managers, substantive theory emerges. The research discovers the five essential processes of owning, visioning, reviewing, producing, and contributing needed for organizational strategic learning to occur. The dimensions of these processes are made explicit and can be used to gauge the health of any organization. The substantive theory also provides insight into the ability of collaborative learning to evolve, flourish, and adapt to the strategic advantage of the organization. Lastly, actionable goals with ten essential elements emerge that link owning, visioning, reviewing, producing, and contributing as a path for all organizations to follow to promote collaborative learning communities and enhance their competitive advantage.

  16. Adaptation of College English Classroom Materials

    Institute of Scientific and Technical Information of China (English)

    余跃

    2015-01-01

    Materials adaptation involves changing existing materials so that they become more suitable for specific learners, teach⁃ers or situations. This paper reviews the current state of this field, and makes suggestions for and gives example of innovative and principled approaches to college English classroom materials adaptation.

  17. Strategic Path Reliability in Information Networks

    OpenAIRE

    Kannan, Rajgopal; Sarangi, Sudipta; Iyengar, Sundaraja Sitharama

    2002-01-01

    We consider a model of an information network where nodes can fail and transmission of information is costly. The formation of paths in such networks is modeled as the Nash equilibrium of an N player routing game. The task of obtaining this equilibrium is shown to be NP-Hard. We derive analytical results to identify conditions under which the equilibrium path is congruent to well known paths such as the most reliable or cheapest neighbor path. The issue of characterizing off-equilibrium paths...

  18. Link prediction based on path entropy

    CERN Document Server

    Xu, Zhongqi; Yang, Jian

    2015-01-01

    Information theory has been taken as a prospective tool for quantifying the complexity of complex networks. In this paper, we first study the information entropy or uncertainty of a path using the information theory. Then we apply the path entropy to the link prediction problem in real-world networks. Specifically, we propose a new similarity index, namely Path Entropy (PE) index, which considers the information entropies of shortest paths between node pairs with penalization to long paths. Empirical experiments demonstrate that PE index outperforms the mainstream link predictors.

  19. Relations between Coherence and Path Information.

    Science.gov (United States)

    Bagan, Emilio; Bergou, János A; Cottrell, Seth S; Hillery, Mark

    2016-04-22

    We find two relations between coherence and path information in a multipath interferometer. The first builds on earlier results for the two-path interferometer, which used minimum-error state discrimination between detector states to provide the path information. For visibility, which was used in the two-path case, we substitute a recently defined l_{1} measure of quantum coherence. The second is an entropic relation in which the path information is characterized by the mutual information between the detector states and the outcome of the measurement performed on them, and the coherence measure is one based on relative entropy.

  20. Toothbrush Adaptations.

    Science.gov (United States)

    Exceptional Parent, 1987

    1987-01-01

    Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)

  1. Ambiguous Adaptation

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Lyngsie, Jacob

    We investigate why some exchange relationships terminate prematurely. We argue that investments in informal governance structures induce premature termination in relationships already governed by formal contracts. The formalized adaptive behavior of formal governance structures and the flexible a...

  2. Attention trees and semantic paths

    Science.gov (United States)

    Giusti, Christian; Pieroni, Goffredo G.; Pieroni, Laura

    2007-02-01

    In the last few decades several techniques for image content extraction, often based on segmentation, have been proposed. It has been suggested that under the assumption of very general image content, segmentation becomes unstable and classification becomes unreliable. According to recent psychological theories, certain image regions attract the attention of human observers more than others and, generally, the image main meaning appears concentrated in those regions. Initially, regions attracting our attention are perceived as a whole and hypotheses on their content are formulated; successively the components of those regions are carefully analyzed and a more precise interpretation is reached. It is interesting to observe that an image decomposition process performed according to these psychological visual attention theories might present advantages with respect to a traditional segmentation approach. In this paper we propose an automatic procedure generating image decomposition based on the detection of visual attention regions. A new clustering algorithm taking advantage of the Delaunay- Voronoi diagrams for achieving the decomposition target is proposed. By applying that algorithm recursively, starting from the whole image, a transformation of the image into a tree of related meaningful regions is obtained (Attention Tree). Successively, a semantic interpretation of the leaf nodes is carried out by using a structure of Neural Networks (Neural Tree) assisted by a knowledge base (Ontology Net). Starting from leaf nodes, paths toward the root node across the Attention Tree are attempted. The task of the path consists in relating the semantics of each child-parent node pair and, consequently, in merging the corresponding image regions. The relationship detected in this way between two tree nodes generates, as a result, the extension of the interpreted image area through each step of the path. The construction of several Attention Trees has been performed and partial

  3. Evaluation of guidewire path reproducibility.

    Science.gov (United States)

    Schafer, Sebastian; Hoffmann, Kenneth R; Noël, Peter B; Ionita, Ciprian N; Dmochowski, Jacek

    2008-05-01

    The number of minimally invasive vascular interventions is increasing. In these interventions, a variety of devices are directed to and placed at the site of intervention. The device used in almost all of these interventions is the guidewire, acting as a monorail for all devices which are delivered to the intervention site. However, even with the guidewire in place, clinicians still experience difficulties during the interventions. As a first step toward understanding these difficulties and facilitating guidewire and device guidance, we have investigated the reproducibility of the final paths of the guidewire in vessel phantom models on different factors: user, materials and geometry. Three vessel phantoms (vessel diameters approximately 4 mm) were constructed having tortuousity similar to the internal carotid artery from silicon tubing and encased in Sylgard elastomer. Several trained users repeatedly passed two guidewires of different flexibility through the phantoms under pulsatile flow conditions. After the guidewire had been placed, rotational c-arm image sequences were acquired (9 in. II mode, 0.185 mm pixel size), and the phantom and guidewire were reconstructed (512(3), 0.288 mm voxel size). The reconstructed volumes were aligned. The centerlines of the guidewire and the phantom vessel were then determined using region-growing techniques. Guidewire paths appear similar across users but not across materials. The average root mean square difference of the repeated placement was 0.17 +/- 0.02 mm (plastic-coated guidewire), 0.73 +/- 0.55 mm (steel guidewire) and 1.15 +/- 0.65 mm (steel versus plastic-coated). For a given guidewire, these results indicate that the guidewire path is relatively reproducible in shape and position.

  4. It Is Better To Give Than It Is To Receive

    Institute of Scientific and Technical Information of China (English)

    孙犁

    2015-01-01

    <正>Intro:In the world millions of people are suffering from hunger especially people in the African areas,while some other people are enjoying some luxuries,such as jewelry,concert tickets,i Pods and so on.Should people give up their luxuries to those who are suffering from hunger?The answer is definitely

  5. Reprint of: Bidding to give in the field

    NARCIS (Netherlands)

    Onderstal, S.; Schram, A.J.H.C.; Soetevent, A.R.

    2014-01-01

    In a door-to-door fundraising field experiment, we study the impact of fundraising mechanisms on charitable giving. We approached about 4500 households, each participating in an all-pay auction, a lottery, a non-anonymous voluntary contribution mechanism (VCM), or an anonymous VCM. In contrast to th

  6. Reprint of : Bidding to give in the field

    NARCIS (Netherlands)

    Onderstal, Sander; Schram, Arthur J. H. C.; Soetevent, Adriaan R.

    2014-01-01

    In a door-to-door fundraising field experiment, we study the impact of fundraising mechanisms on charitable giving. We approached about 4500 households, each participating in an all-pay auction, a lottery, a non-anonymous voluntary contribution mechanism (VCM), or an anonymous VCM. In contrast to th

  7. Undergraduate Financial Aid and Subsequent Giving Behavior. Discussion Paper.

    Science.gov (United States)

    Dugan, Kelly; Mullin, Charles H.; Siegfried, John J.

    Data on 2,822 Vanderbilt University graduates were used to investigate alumni giving behavior during the 8 years after graduation. A two-stage model accounting for individual truncation was used first to estimate the likelihood of making a contribution and second to estimate the average gift size conditional on contributing. The type of financial…

  8. New Trends in Name-Giving in Turkey

    Directory of Open Access Journals (Sweden)

    Erol Sakallı

    2016-07-01

    Full Text Available The author gives a brief review of traditional customs of name-giving in Turkey and analyses some recent trends. The observations are based on 1270 Turkish names collected from the author’s students and reflecting naming practices in Turkey over last several decades. The data has been collected randomly regardless of social, regional, religious or ethnic backgrounds, all names being accompanied by the indication of the age of their bearers. The collected data were categorized into three groups: commemorative names, desiderata names and fortuitous names. This categorization shows the distribution of Turkish names and the changes in the stock of personal names over the years. The traditional name-giving customs are still observed in Turkey, however, new trends are becoming more prominent in the country. The author explains the changes with reference to social evolution which incites young educated parents, most of whom are university graduates living in urban areas and having only one child, to adopt new strategies of name-giving testifying their increasing individualism and weakening ties with traditions.

  9. Formal Speaking——How to Give a Great Speech

    Institute of Scientific and Technical Information of China (English)

    JosephDeVeto

    2004-01-01

    Most successful people in the world are very good at “public speaking”.They know how to get up in front of a crowd and give a “formal speech”. They know how to move people, how to get them to take action. It's not easy to do, but

  10. Reciprocity Revisited : Give and Take in Dutch and Immigrant Families

    NARCIS (Netherlands)

    Komter, Aafke; Schans, Djamila

    2008-01-01

    The idea that reciprocity is the basic principle underlying forms of social organization, among which the family, is as old as classical anthropology and sociology. The essence of the principle is that giving prompts receiving, thereby creating forms of ongoing exchange and durable cooperation. Reci

  11. A Conversation Model Enabling Intelligent Agents to Give Emotional Support

    NARCIS (Netherlands)

    Van der Zwaan, J.M.; Dignum, V.; Jonker, C.M.

    2012-01-01

    In everyday life, people frequently talk to others to help them deal with negative emotions. To some extent, everybody is capable of comforting other people, but so far conversational agents are unable to deal with this type of situation. To provide intelligent agents with the capability to give emo

  12. 2 Authors Say Routledge Recycled Their Work without Giving Credit

    Science.gov (United States)

    Bartlett, Thomas

    2008-01-01

    This article reports on two authors' work that has been recycled by Routledge without giving credit or royalty. When William E. Deal casually flipped through "Theory for Performance Studies: A Student's Guide," published this year by Routledge, he noticed a few familiar sentences. After taking a closer look, Mr. Deal, a professor of religious…

  13. Dyck Paths, Standard Young Tableaux, and Pattern Avoiding Permutations

    CERN Document Server

    Gudmundsson, Hilmar

    2009-01-01

    We present a generating function and a closed counting formula in two variables that enumerate a family of classes of permutations that avoid or contain an increasing pattern of length three and have a prescribed number of occurrences of another pattern of length three. This gives a refinement of some previously studied statistics, most notably one by Noonan. The formula is also shown to enumerate a family of classes of Dyck paths and Standard Young Tableaux, and a bijection is given between the corresponding classes of these two families of objects. Finally, the results obtained are used to solve an optimization problem for a certain card game.

  14. The Path Integral Quantization corresponding to the Deformed Heisenberg Algebra

    CERN Document Server

    Pramanik, Souvik; Moussa, Mohamed; Ali, Ahmed Farag

    2014-01-01

    In this paper, we analyze a deformation of the Heisenberg algebra consistent with both the generalized uncertainty principle and doubly special relativity. We observe that this algebra can give rise to fractional derivatives terms in the corresponding quantum mechanical Hamiltonian. However, a formal meaning can be given to such fractional derivative terms, using the theory of harmonic extensions of functions. Thus we obtain the expression of the propagator of path integral corresponding to this deformed Heisenberg algebra. In fact, we explicitly evaluate this expression for a free particle in one dimension and check its consistency.

  15. Q-system Cluster Algebras, Paths and Total Positivity

    Directory of Open Access Journals (Sweden)

    Philippe Di Francesco

    2010-02-01

    Full Text Available In the first part of this paper, we provide a concise review of our method of solution of the A_r Q-systems in terms of the partition function of paths on a weighted graph. In the second part, we show that it is possible to modify the graphs and transfer matrices so as to provide an explicit connection to the theory of planar networks introduced in the context of totally positive matrices by Fomin and Zelevinsky. As an illustration of the further generality of our method, we apply it to give a simple solution for the rank 2 affine cluster algebras studied by Caldero and Zelevinsky.

  16. Give clean air the economic value it deserves

    Energy Technology Data Exchange (ETDEWEB)

    Verhagen, H. [United Air Fund, Amsterdam (Netherlands)

    2000-07-01

    India contributes more to the management of the atmosphere than a country like the Netherlands. This is not to the credit of the Indian government; rather, it is merely a consequence of poverty. Poor people use almost no fossil fuels and emit almost no CO2. Paying developing countries for this environmental service to the world community would create a financial incentive to continue to provide this service in the future, while at the same time generating additional funds to improve the living standards of the poorest people. The attractiveness of this approach depends on one important assumption: the conventional development path - economic growth implies emissions - must be replaced by a sustainable development path delinks economic growth from increasing emissions. Rich industrialised countries also have an interest in such decoupling. The compensation they pay the developing countries would fall proportionately to the reduction of their CO2 emissions. So an incentive is created on both sides to switch over to a low-carbon energy strategy. After the completion of this transition, every country can use as much energy as it wants, because energy consumption would then no longer cause CO2 emissions. This is the picture of the future to which the United Air Fund aspires.

  17. Hedonic "adaptation"

    OpenAIRE

    2008-01-01

    People live in a world in which they are surrounded by potential disgust elicitors such as ``used'' chairs, air, silverware, and money as well as excretory activities. People function in this world by ignoring most of these, by active avoidance, reframing, or adaptation. The issue is particularly striking for professions, such as morticians, surgeons, or sanitation workers, in which there is frequent contact with major disgust elicitors. In this study, we study the ``adaptation'' process to d...

  18. Strategic Adaptation

    DEFF Research Database (Denmark)

    Andersen, Torben Juul

    2015-01-01

    This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related...... concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation...

  19. Paths and cycles of hypergraphs

    Institute of Scientific and Technical Information of China (English)

    王建方; Tony; T.Lee

    1999-01-01

    Hypergraphs are the most general structures in discrete mathematics. Acyclic hypergraphs have been proved very useful in relational databases. New systems of axioms for paths, connectivity and cycles of hypergraphs are constructed. The systems suit the structure properties of relational databases. The concepts of pseudo cycles and essential cycles of hypergraphs are introduced. They are relative to each other. Whether a family of cycles of a hypergraph is dependent or independent is defined. An enumeration formula for the maximum number of independent essential cycles of a hypergraph is given.

  20. Path of Chinese institutional modernization

    OpenAIRE

    Sahoo, Ganeswar

    2009-01-01

    We see the progress today that China has developed a treasure of modernity in terms of its World figure both in economic development and its strong military power with countless path of ups and downs in the past. We are more concerned with the historical study of its institutional modernization than a mere philosophical debate over its development and can discuss its various levels of struggle for ‘Substitute Modernity’2 since mid-19th century(the two opium wars) to till date.

  1. Deterministic Circular Self Test Path

    Institute of Scientific and Technical Information of China (English)

    WEN Ke; HU Yu; LI Xiaowei

    2007-01-01

    Circular self test path (CSTP) is an attractive technique for testing digital integrated circuits(IC) in the nanometer era, because it can easily provide at-speed test with small test data volume and short test application time. However, CSTP cannot reliably attain high fault coverage because of difficulty of testing random-pattern-resistant faults. This paper presents a deterministic CSTP (DCSTP) structure that consists of a DCSTP chain and jumping logic, to attain high fault coverage with low area overhead. Experimental results on ISCAS'89 benchmarks show that 100% fault coverage can be obtained with low area overhead and CPU time, especially for large circuits.

  2. Communication path for extreme environments

    Science.gov (United States)

    Jorgensen, Charles C. (Inventor); Betts, Bradley J. (Inventor)

    2010-01-01

    Methods and systems for using one or more radio frequency identification devices (RFIDs), or other suitable signal transmitters and/or receivers, to provide a sensor information communication path, to provide location and/or spatial orientation information for an emergency service worker (ESW), to provide an ESW escape route, to indicate a direction from an ESW to an ES appliance, to provide updated information on a region or structure that presents an extreme environment (fire, hazardous fluid leak, underwater, nuclear, etc.) in which an ESW works, and to provide accumulated thermal load or thermal breakdown information on one or more locations in the region.

  3. Uncommon paths in quantum physics

    CERN Document Server

    Kazakov, Konstantin V

    2014-01-01

    Quantum mechanics is one of the most fascinating, and at the same time most controversial, branches of contemporary science. Disputes have accompanied this science since its birth and have not ceased to this day. Uncommon Paths in Quantum Physics allows the reader to contemplate deeply some ideas and methods that are seldom met in the contemporary literature. Instead of widespread recipes of mathematical physics, based on the solutions of integro-differential equations, the book follows logical and partly intuitional derivations of non-commutative algebra. Readers can directly penetrate the

  4. Gibbs Ensembles of Nonintersecting Paths

    CERN Document Server

    Borodin, Alexei

    2008-01-01

    We consider a family of determinantal random point processes on the two-dimensional lattice and prove that members of our family can be interpreted as a kind of Gibbs ensembles of nonintersecting paths. Examples include probability measures on lozenge and domino tilings of the plane, some of which are non-translation-invariant. The correlation kernels of our processes can be viewed as extensions of the discrete sine kernel, and we show that the Gibbs property is a consequence of simple linear relations satisfied by these kernels. The processes depend on infinitely many parameters, which are closely related to parametrization of totally positive Toeplitz matrices.

  5. Longest-path attacks on complex networks

    CERN Document Server

    Pu, Cunlai

    2014-01-01

    We investigate the longest-path attacks on complex networks. Specifically, we remove approximately the longest simple path from a network iteratively until there are no paths left in the network. We propose two algorithms, the random augmenting approach (RPA) and the Hamilton-path based approach (HPA), for finding the approximately longest simple path in a network. Results demonstrate that steps of longest-path attacks increase with network density linearly for random networks, while exponentially increasing for scale-free networks. The more homogeneous the degree distribution is, the more fragile the network, which is totally different from the previous results of node or edge attacks. HPA is generally more efficient than RPA in the longest-path attacks of complex networks. These findings further help us understand the vulnerability of complex systems, better protect complex systems, and design more tolerant complex systems.

  6. Is adaptation. Truly an adaptation? Is adaptation. Truly an adaptation?

    Directory of Open Access Journals (Sweden)

    Thais Flores Nogueira Diniz

    2008-04-01

    Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning. The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition

  7. An Application of Self-Organizing Map for Multirobot Multigoal Path Planning with Minmax Objective.

    Science.gov (United States)

    Faigl, Jan

    2016-01-01

    In this paper, Self-Organizing Map (SOM) for the Multiple Traveling Salesman Problem (MTSP) with minmax objective is applied to the robotic problem of multigoal path planning in the polygonal domain. The main difficulty of such SOM deployment is determination of collision-free paths among obstacles that is required to evaluate the neuron-city distances in the winner selection phase of unsupervised learning. Moreover, a collision-free path is also needed in the adaptation phase, where neurons are adapted towards the presented input signal (city) to the network. Simple approximations of the shortest path are utilized to address this issue and solve the robotic MTSP by SOM. Suitability of the proposed approximations is verified in the context of cooperative inspection, where cities represent sensing locations that guarantee to "see" the whole robots' workspace. The inspection task formulated as the MTSP-Minmax is solved by the proposed SOM approach and compared with the combinatorial heuristic GENIUS. The results indicate that the proposed approach provides competitive results to GENIUS and support applicability of SOM for robotic multigoal path planning with a group of cooperating mobile robots. The proposed combination of approximate shortest paths with unsupervised learning opens further applications of SOM in the field of robotic planning.

  8. An Application of Self-Organizing Map for Multirobot Multigoal Path Planning with Minmax Objective

    Directory of Open Access Journals (Sweden)

    Jan Faigl

    2016-01-01

    Full Text Available In this paper, Self-Organizing Map (SOM for the Multiple Traveling Salesman Problem (MTSP with minmax objective is applied to the robotic problem of multigoal path planning in the polygonal domain. The main difficulty of such SOM deployment is determination of collision-free paths among obstacles that is required to evaluate the neuron-city distances in the winner selection phase of unsupervised learning. Moreover, a collision-free path is also needed in the adaptation phase, where neurons are adapted towards the presented input signal (city to the network. Simple approximations of the shortest path are utilized to address this issue and solve the robotic MTSP by SOM. Suitability of the proposed approximations is verified in the context of cooperative inspection, where cities represent sensing locations that guarantee to “see” the whole robots’ workspace. The inspection task formulated as the MTSP-Minmax is solved by the proposed SOM approach and compared with the combinatorial heuristic GENIUS. The results indicate that the proposed approach provides competitive results to GENIUS and support applicability of SOM for robotic multigoal path planning with a group of cooperating mobile robots. The proposed combination of approximate shortest paths with unsupervised learning opens further applications of SOM in the field of robotic planning.

  9. Robust adaptive beamforming for MIMO monopulse radar

    Science.gov (United States)

    Rowe, William; Ström, Marie; Li, Jian; Stoica, Petre

    2013-05-01

    Researchers have recently proposed a widely separated multiple-input multiple-output (MIMO) radar using monopulse angle estimation techniques for target tracking. The widely separated antennas provide improved tracking performance by mitigating complex target radar cross-section fades and angle scintillation. An adaptive array is necessary in this paradigm because the direct path from any transmitter could act as a jammer at a receiver. When the target-free covariance matrix is not available, it is critical to include robustness into the adaptive beamformer weights. This work explores methods of robust adaptive monopulse beamforming techniques for MIMO tracking radar.

  10. Solving a Hamiltonian Path Problem with a bacterial computer

    Directory of Open Access Journals (Sweden)

    Treece Jessica

    2009-07-01

    Full Text Available Abstract Background The Hamiltonian Path Problem asks whether there is a route in a directed graph from a beginning node to an ending node, visiting each node exactly once. The Hamiltonian Path Problem is NP complete, achieving surprising computational complexity with modest increases in size. This challenge has inspired researchers to broaden the definition of a computer. DNA computers have been developed that solve NP complete problems. Bacterial computers can be programmed by constructing genetic circuits to execute an algorithm that is responsive to the environment and whose result can be observed. Each bacterium can examine a solution to a mathematical problem and billions of them can explore billions of possible solutions. Bacterial computers can be automated, made responsive to selection, and reproduce themselves so that more processing capacity is applied to problems over time. Results We programmed bacteria with a genetic circuit that enables them to evaluate all possible paths in a directed graph in order to find a Hamiltonian path. We encoded a three node directed graph as DNA segments that were autonomously shuffled randomly inside bacteria by a Hin/hixC recombination system we previously adapted from Salmonella typhimurium for use in Escherichia coli. We represented nodes in the graph as linked halves of two different genes encoding red or green fluorescent proteins. Bacterial populations displayed phenotypes that reflected random ordering of edges in the graph. Individual bacterial clones that found a Hamiltonian path reported their success by fluorescing both red and green, resulting in yellow colonies. We used DNA sequencing to verify that the yellow phenotype resulted from genotypes that represented Hamiltonian path solutions, demonstrating that our bacterial computer functioned as expected. Conclusion We successfully designed, constructed, and tested a bacterial computer capable of finding a Hamiltonian path in a three node

  11. Arduino & RepRap - Creating Wealth by Giving it Away

    DEFF Research Database (Denmark)

    2011-01-01

    , growth in wealth is longevity and prosperity. Is it possible to grow wealth independently of money? This talk will be from Adrian Bowyer - creator of RepRap, the open-source replicating 3D printer - and from David Cuartielles - creator of Arduino, the open-source microcontroller. Both projects have...... founded significant and growing industries - and hence significant and growing wealth - by giving away all the data required to build RepRaps and Arduinos completely free. They have also short-circuited most conventional industrial infrastructure by placing the ability to create wealth directly...... in the hands of private individuals. The presenters contend that this is the way of the future: companies, and - more importantly - those private individuals will be giving away their primary products and making a living on the sideline activities that such donations attract. Software has been heading...

  12. Path Following of an Underactuated AUV Based on Fuzzy Backstepping Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Xiao Liang

    2016-06-01

    Full Text Available This paper addresses the path following problem of an underactuated autonomous underwater vehicle (AUV with the aim of dealing with parameter uncertainties and current disturbances. An adaptive robust control system was proposed by employing fuzzy logic, backstepping and sliding mode control theory. Fuzzy logic theory is adopted to approximate unknown system function, and the controller was designed by combining sliding mode control with backstepping thought. Firstly, the longitudinal speed was controlled, then the yaw angle was made as input of path following error to design the calm function and the change rate of path parameters. The controller stability was proved by Lyapunov stable theory. Simulation and outfield tests were conducted and the results showed that the controller is of excellent adaptability and robustness in the presence of parameter uncertainties and external disturbances. It is also shown to be able to avoid the chattering of AUV actuators.

  13. Robust Video Stabilization Using Particle Keypoint Update and l₁-Optimized Camera Path.

    Science.gov (United States)

    Jeon, Semi; Yoon, Inhye; Jang, Jinbeum; Yang, Seungji; Kim, Jisung; Paik, Joonki

    2017-02-10

    Acquisition of stabilized video is an important issue for various type of digital cameras. This paper presents an adaptive camera path estimation method using robust feature detection to remove shaky artifacts in a video. The proposed algorithm consists of three steps: (i) robust feature detection using particle keypoints between adjacent frames; (ii) camera path estimation and smoothing; and (iii) rendering to reconstruct a stabilized video. As a result, the proposed algorithm can estimate the optimal homography by redefining important feature points in the flat region using particle keypoints. In addition, stabilized frames with less holes can be generated from the optimal, adaptive camera path that minimizes a temporal total variation (TV). The proposed video stabilization method is suitable for enhancing the visual quality for various portable cameras and can be applied to robot vision, driving assistant systems, and visual surveillance systems.

  14. Intelligent Web-Based Learning System with Personalized Learning Path Guidance

    Science.gov (United States)

    Chen, C. M.

    2008-01-01

    Personalized curriculum sequencing is an important research issue for web-based learning systems because no fixed learning paths will be appropriate for all learners. Therefore, many researchers focused on developing e-learning systems with personalized learning mechanisms to assist on-line web-based learning and adaptively provide learning paths…

  15. General framework for transfer path analysis: History, theory and classification of techniques

    NARCIS (Netherlands)

    Van der Seijs, M.V.; De Klerk, D.; Rixen, D.J.

    2015-01-01

    Transfer Path Analysis (TPA) designates the family of test-based methodologies to study the transmission of mechanical vibrations. Since the first adaptation of electric network analogies in the field of mechanical engineering a century ago, a multitude of TPA methods have emerged and found their wa

  16. Beijing Specialists Give Free Medical Treatment in Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>To help improve the physical conditions of the people in the Hui ethnic minority areas of Yunnan Province, from December 6 to 11,2005, a 10-member medical team of specialists from the Capital went to the Weishan Yi and Hui Ethnic Minority Autonomous County of Dali Prefecture and Xundian Hui and Yi Ethnic Minority Autonomous County of Kunming City to give free medical treatment for 6 days. This activity was

  17. PC-give and David Hendry's econometric methodology

    OpenAIRE

    Neil R. Ericsson; Julia Campos; Hong-Anh Tran

    1991-01-01

    This paper summarizes David Hendry's empirical econometric methodology, unifying discussions in many of his and his co-authors' papers. Then, we describe how Hendry's suite of computer programs PC-GIVE helps users implement that methodology. Finally, we illustrate that methodology and the programs with three empirical examples: post­war narrow money demand in the United Kingdom, nominal income determination in the United Kingdom from Friedman and Schwartz (1982), and consumers' expenditure in...

  18. A Conversation Model Enabling Intelligent Agents to Give Emotional Support

    OpenAIRE

    Van der Zwaan, J.M.; Dignum, V; Jonker, C.M.

    2012-01-01

    In everyday life, people frequently talk to others to help them deal with negative emotions. To some extent, everybody is capable of comforting other people, but so far conversational agents are unable to deal with this type of situation. To provide intelligent agents with the capability to give emotional support, we propose a domain-independent conversational model that is based on topics suggested by cognitive appraisal theories of emotion and the 5-phase model that is used to structure onl...

  19. MP I joint giving way--a case study.

    Science.gov (United States)

    Lohrer, H

    2001-02-01

    A case history of a 26 year old international class female 400 m hurdle sprinter is presented. While sprinting she felt a sudden and very intensive pain at her left hallux. After this she was unable to run and had episodes of giving way in the MP I joint elicited by minor activity. Operative investigation revealed a broad disruption of the MP I medial collateral ligament. After periosteal flap repair and early functional aftertreatment she returned to full high level sports ability.

  20. Economics of adaptation to climate change; Economie de l'adaptation au changement climatique

    Energy Technology Data Exchange (ETDEWEB)

    Perthuis, Ch.; Hallegatte, St.; Lecocq, F.

    2010-02-15

    This report proposes a general economic framework for the issue of adaptation to climate change in order to help public and private actors to build up efficient adaptation strategies. It proposes a general definition of adaptation, identifies the major stakes for these strategies, and discusses the assessment of global costs of adaptation to climate change. It discusses the role and modalities of public action and gives some examples of possible adaptation measures in some important sectors (building and town planning, energy and transport infrastructures, water and agriculture, ecosystems, insurance). It examines the regional and national dimensions of adaptation and their relationship, and defines steps for implementing an adaptation strategy. It describes and discusses the use of economic tools in the elaboration of an adaptation strategy, i.e. how to take uncertainties into account, which scenarios to choose, how to use economic calculations to assess adaptation policies

  1. Giving an account of one's pain in the anthropological interview.

    Science.gov (United States)

    Buchbinder, Mara

    2010-03-01

    In this paper, I analyze the illness stories narrated by a mother and her 13-year-old son as part of an ethnographic study of child chronic pain sufferers and their families. In examining some of the moral, relational and communicative challenges of giving an account of one's pain, I focus on what is left out of some accounts of illness and suffering and explore some possible reasons for these elisions. Drawing on recent work by Judith Butler (Giving an Account of Oneself, 2005), I investigate how the pragmatic context of interviews can introduce a form of symbolic violence to narrative accounts. Specifically, I use the term "genre of complaint" to highlight how anthropological research interviews in biomedical settings invoke certain typified forms of suffering that call for the rectification of perceived injustices. Interview narratives articulated in the genre of complaint privilege specific types of pain and suffering and cast others into the background. Giving an account of one's pain is thus a strategic and selective process, creating interruptions and silences as much as moments of clarity. Therefore, I argue that medical anthropologists ought to attend more closely to the institutional structures and relations that shape the production of illness narratives in interview encounters.

  2. Integrated assignment and path planning

    Science.gov (United States)

    Murphey, Robert A.

    2005-11-01

    A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact

  3. Path Network Recovery Using Remote Sensing Data and Geospatial-Temporal Semantic Graphs

    Energy Technology Data Exchange (ETDEWEB)

    McLendon, William C.,; Brost, Randolph

    2016-05-01

    Remote sensing systems produce large volumes of high-resolution images that are difficult to search. The GeoGraphy (pronounced Geo-Graph-y) framework [2, 20] encodes remote sensing imagery into a geospatial-temporal semantic graph representation to enable high level semantic searches to be performed. Typically scene objects such as buildings and trees tend to be shaped like blocks with few holes, but other shapes generated from path networks tend to have a large number of holes and can span a large geographic region due to their connectedness. For example, we have a dataset covering the city of Philadelphia in which there is a single road network node spanning a 6 mile x 8 mile region. Even a simple question such as "find two houses near the same street" might give unexpected results. More generally, nodes arising from networks of paths (roads, sidewalks, trails, etc.) require additional processing to make them useful for searches in GeoGraphy. We have assigned the term Path Network Recovery to this process. Path Network Recovery is a three-step process involving (1) partitioning the network node into segments, (2) repairing broken path segments interrupted by occlusions or sensor noise, and (3) adding path-aware search semantics into GeoQuestions. This report covers the path network recovery process, how it is used, and some example use cases of the current capabilities.

  4. Multiple Social Identities Enhance Health Post-Retirement Because They Are a Basis for Giving Social Support

    Directory of Open Access Journals (Sweden)

    Niklas K Steffens

    2016-10-01

    Full Text Available We examine the extent to which multiple social identities are associated with enhanced health and well-being in retirement because they provide a basis for giving and receiving social support. Results from a cross-sectional study show that retirees (N = 171 who had multiple social identities following (but not prior to retirement report being (a more satisfied with retirement, (b in better health, and (c more satisfied with life in general. Furthermore, mediation analyses revealed an indirect path from multiple social identities to greater satisfaction with retirement and better health through greater provision, but not receipt, of social support to others. These findings are the first to point to the value of multiple group membership post-retirement as a basis for increased opportunities to give meaningful support to others. We discuss the theoretical and practical implications for the management of multiple identities in the process of significant life transitions such as retirement.

  5. Improved approximations for robust mincut and shortest path

    CERN Document Server

    Polishchuk, Valentin

    2010-01-01

    In two-stage robust optimization the solution to a problem is built in two stages: In the first stage a partial, not necessarily feasible, solution is exhibited. Then the adversary chooses the "worst" scenario from a predefined set of scenarios. In the second stage, the first-stage solution is extended to become feasible for the chosen scenario. The costs at the second stage are larger than at the first one, and the objective is to minimize the total cost paid in the two stages. We give a 2-approximation algorithm for the robust mincut problem and a ({\\gamma}+2)-approximation for the robust shortest path problem, where {\\gamma} is the approximation ratio for the Steiner tree. This improves the factors (1+\\sqrt2) and 2({\\gamma}+2) from [Golovin, Goyal and Ravi. Pay today for a rainy day: Improved approximation algorithms for demand-robust min-cut and shortest path problems. STACS 2006]. In addition, our solution for robust shortest path is simpler and more efficient than the earlier ones; this is achieved by a...

  6. Adaptive test

    DEFF Research Database (Denmark)

    Kjeldsen, Lars Peter; Rose, Mette

    2010-01-01

    Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale.......Artikelen er en evaluering af de adaptive tests, som blev indført i folkeskolen. Artiklen sætter særligt fokus på evaluering i folkeskolen, herunder bidrager den med vejledning til evaluering, evalueringsværktøjer og fagspecifkt evalueringsmateriale....

  7. Strategic Team AI Path Plans: Probabilistic Pathfinding

    Directory of Open Access Journals (Sweden)

    Tng C. H. John

    2008-01-01

    Full Text Available This paper proposes a novel method to generate strategic team AI pathfinding plans for computer games and simulations using probabilistic pathfinding. This method is inspired by genetic algorithms (Russell and Norvig, 2002, in that, a fitness function is used to test the quality of the path plans. The method generates high-quality path plans by eliminating the low-quality ones. The path plans are generated by probabilistic pathfinding, and the elimination is done by a fitness test of the path plans. This path plan generation method has the ability to generate variation or different high-quality paths, which is desired for games to increase replay values. This work is an extension of our earlier work on team AI: probabilistic pathfinding (John et al., 2006. We explore ways to combine probabilistic pathfinding and genetic algorithm to create a new method to generate strategic team AI pathfinding plans.

  8. Crack path predictions and experiments in plane structures considering anisotropic properties and material interfaces

    Directory of Open Access Journals (Sweden)

    P.O. Judt

    2015-10-01

    Full Text Available In many engineering applications special requirements are directed to a material's fracture behavior and the prediction of crack paths. Especially if the material exhibits anisotropic elastic properties or fracture toughnesses, e.g. in textured or composite materials, the simulation of crack paths is challenging. Here, the application of path independent interaction integrals (I-integrals, J-, L- and M-integrals is beneficial for an accurate crack tip loading analysis. Numerical tools for the calculation of loading quantities using these path-invariant integrals are implemented into the commercial finite element (FE-code ABAQUS. Global approaches of the integrals are convenient considering crack tips approaching other crack faces, internal boundaries or material interfaces. Curved crack faces require special treatment with respect to integration contours. Numerical crack paths are predicted based on FE calculations of the boundary value problem in connection with an intelligent adaptive re-meshing algorithm. Considering fracture toughness anisotropy and accounting for inelastic effects due to small plastic zones in the crack tip region, the numerically predicted crack paths of different types of specimens with material interfaces and internal boundaries are compared to subcritically grown paths obtained from experiments.

  9. Path planning based on sliding window and variant A*algorithm for quadruped robot

    Institute of Scientific and Technical Information of China (English)

    张慧

    2016-01-01

    In order to improve the adaptability of the quadruped robot in complex environments , a path planning method based on sliding window and variant A * algorithm for quadruped robot is presen-ted .To improve the path planning efficiency and robot security , an incremental A*search algorithm ( IA*) and the A*algorithm having obstacle grids extending ( EA*) are proposed respectively .The IA* algorithm firstly searches an optimal path based on A * algorithm, then a new route from the current path to the new goal projection is added to generate a suboptimum route incrementally .In comparison with traditional method solving path planning problem from scratch , the IA* enables the robot to plan path more efficiently .EA* extends the obstacle by means of increasing grid g-value, which makes the route far away from the obstacle and avoids blocking the narrow passage .To navi-gate the robot running smoothly , a quadratic B-spline interpolation is applied to smooth the path . Simulation results illustrate that the IA* algorithm can increase the re-planning efficiency more than 5 times and demonstrate the effectiveness of the EA * algorithm.

  10. Least expected time paths in stochastic, time-varying transportation networks

    Energy Technology Data Exchange (ETDEWEB)

    Miller-Hooks, E.D. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Civil and Environmental Engineering; Mahmassani, H.S. [Univ. of Texas, Austin, TX (United States)

    1999-06-01

    The authors consider stochastic, time-varying transportation networks, where the arc weights (arc travel times) are random variables with probability distribution functions that vary with time. Efficient procedures are widely available for determining least time paths in deterministic networks. In stochastic but time-invariant networks, least expected time paths can be determined by setting each random arc weight to its expected value and solving an equivalent deterministic problem. This paper addresses the problem of determining least expected time paths in stochastic, time-varying networks. Two procedures are presented. The first procedure determines the a priori least expected time paths from all origins to a single destination for each departure time in the peak period. The second procedure determines lower bounds on the expected times of these a priori least expected time paths. This procedure determines an exact solution for the problem where the driver is permitted to react to revealed travel times on traveled links en route, i.e. in a time-adaptive route choice framework. Modifications to each of these procedures for determining least expected cost (where cost is not necessarily travel time) paths and lower bounds on the expected costs of these paths are given. Extensive numerical tests are conducted to illustrate the algorithms` computational performance as well as the properties of the solution.

  11. Stress path dependent hydromechanical behaviour of heterogeneous carbonate rock

    Directory of Open Access Journals (Sweden)

    Dimanov A.

    2010-06-01

    Full Text Available The influence of stress paths, representative of reservoir conditions, on the hydromechanical behavior of a moderately heterogeneous carbonate has been investigated. Multiscale structural heterogeneities, common for instance in carbonate rocks, can strongly alter the mechanical response and significantly influence the evolution of flow properties with stress. Using a triaxial cell, the permeability evolutions during compression and the effects of brittle (fracture and plastic (pore collapse deformations at yield, were measured. A strong scattering was observed on the mechanical response both in term of compressibility and failure threshold. Using the porosity scaling predicted by an adapted effective medium theory (based on crack growth under Hertzian contact, we have rescaled the critical pressures by the normalized porosity deviation. This procedure reduces efficiently the scattering, revealing in the framework of proportional stress path loading, a linear relation between the critical pressures and the stress path parameter through all the deformation regimes. It leads to a new formulation for the critical state envelope in the 'mean stress, deviatoric stress' diagram. The attractive feature of this new yield envelope formulation relies on the fact that only the two most common different mechanical tests 'Uniaxial Compression' and 'Hydrostatic Compression', are needed to define entirely the yield envelope. Volumic strains and normalized permeabilities are finally mapped in the stresses diagram and correlated.

  12. Intelligent Online Path Planning for UAVs in Adversarial Environments

    Directory of Open Access Journals (Sweden)

    Xingguang Peng

    2012-03-01

    Full Text Available Online path planning (OPP for unmanned aerial vehicles (UAVs is a basic issue of intelligent flight and is indeed a dynamic multi‐objective optimization problem (DMOP. In this paper, an OPP framework is proposed in the sense of model predictive control (MPC to continuously update the environmental information for the planner. For solving the DMOP involved in the MPC we propose a dynamic multi‐objective evolutionary algorithm based on linkage and prediction (LP‐DMOEA. Within this algorithm, the historical Pareto sets are collected and analysed to enhance the performance. For intelligently selecting the best path from the output of the OPP, the Bayesian network and fuzzy logic are used to quantify the bias to each optimization objective. The DMOEA is validated on three benchmark problems characterized by different changing types in decision and objective spaces. Moreover, the simulation results show that the LP‐DMOEA overcomes the restart method for OPP. The decision‐making method for solution selection can assess the situation in an adversarial environment and accordingly adapt the path planner.

  13. Design of active N-path filters

    NARCIS (Netherlands)

    Darvishi, Milad; Zee, van der Ronan; Nauta, Bram

    2013-01-01

    A design methodology for synthesis of active N-path bandpass filters is introduced. Based on this methodology, a 0.1-to-1.2 GHz tunable 6th-order N-path channel-select filter in 65 nm LP CMOS is introduced. It is based on coupling N-path filters with gyrators, achieving a “flat” passband shape and h

  14. Path Planning Control for Mobile Robot

    Directory of Open Access Journals (Sweden)

    Amenah A.H. Salih

    2011-01-01

    Full Text Available Autonomous motion planning is important area of robotics research. This type of planning relieves human operator from tedious job of motion planning. This reduces the possibility of human error and increase efficiency of whole process. This research presents a new algorithm to plan path for autonomous mobile robot based on image processing techniques by using wireless camera that provides the desired image for the unknown environment . The proposed algorithm is applied on this image to obtain a optimal path for the robot. It is based on the observation and analysis of the obstacles that lying in the straight path between the start and the goal point by detecting these obstacles, analyzing and studying their shapes, positions and points of intersection with the straight path to find the nearly optimal path which connects the start and the goal point.This work has theoretical part and experimental part. The theoretical part includes building a MATLAB program which is applied to environment image to find the nearly optimal path .MATLAB - C++.NET interface is accomplished then to supply the path information for C++.NET program which is done for programming the pioneer mobile robot to achieve the desired path. The experimental part includes using wireless camera that takes an image for the environment and send it to the computer which processes this image and sends ( by wireless connection the resulted path information to robot which programmed in C++.NET program to walk according to this path.So, the overall system can be represented by:Wireless camera – computer – wireless connection for the mobile robot .The experimental work including some experiments shows that the developed mobile robot (pioneer p3-dx travels successfully from the start point and reach the goal point across the optimal path (according to time and power which is obtained as result of the proposed path planning algorithm introduced in this paper.

  15. N-slit interference: Path integrals, Bohmian trajectories

    CERN Document Server

    Sbitnev, Valeriy I

    2010-01-01

    Path integrals give a possibility to compute in details routes of particles from particle sources through slit gratings and further to detectors. The path integral for a particle passing through the Gaussian slit results in the Gaussian wavepacket. The wavepackets prepared on N slits and superposed together give rise to interference pattern in the near-field zone. It transforms to diffraction in the far-field zone represented by divergent principal rays, at that all rays are partitioned from each other by (N-2) subsidiary rays. The Bohmian trajectories in the near-field zone of N-slit gratings show wavy behavior. And they become straight in the far-field zone. The trajectories show zigzag behavior on the interference Talbot carpet (ratio of particle wavelength to a distance between slits are much smaller than 1 and N >> 1). Namely, the trajectories prefer to pass through caustics and avoid lacunae, i.e., places with small probability densities. Monochromatic thermal neutrons (wavelength=0.5 nm) simulate radia...

  16. Langevin equation path integral ground state.

    Science.gov (United States)

    Constable, Steve; Schmidt, Matthew; Ing, Christopher; Zeng, Tao; Roy, Pierre-Nicholas

    2013-08-15

    We propose a Langevin equation path integral ground state (LePIGS) approach for the calculation of ground state (zero temperature) properties of molecular systems. The approach is based on a modification of the finite temperature path integral Langevin equation (PILE) method (J. Chem. Phys. 2010, 133, 124104) to the case of open Feynman paths. Such open paths are necessary for a ground state formulation. We illustrate the applicability of the method using model systems and the weakly bound water-parahydrogen dimer. We show that the method can lead to converged zero point energies and structural properties.

  17. Techniques and applications of path integration

    CERN Document Server

    Schulman, L S

    2005-01-01

    A book of techniques and applications, this text defines the path integral and illustrates its uses by example. It is suitable for advanced undergraduates and graduate students in physics; its sole prerequisite is a first course in quantum mechanics. For applications requiring specialized knowledge, the author supplies background material.The first part of the book develops the techniques of path integration. Topics include probability amplitudes for paths and the correspondence limit for the path integral; vector potentials; the Ito integral and gauge transformations; free particle and quadra

  18. Cooperative path planning of unmanned aerial vehicles

    CERN Document Server

    Tsourdos, Antonios; Shanmugavel, Madhavan

    2010-01-01

    An invaluable addition to the literature on UAV guidance and cooperative control, Cooperative Path Planning of Unmanned Aerial Vehicles is a dedicated, practical guide to computational path planning for UAVs. One of the key issues facing future development of UAVs is path planning: it is vital that swarm UAVs/ MAVs can cooperate together in a coordinated manner, obeying a pre-planned course but able to react to their environment by communicating and cooperating. An optimized path is necessary in order to ensure a UAV completes its mission efficiently, safely, and successfully.

  19. A note on the path interval distance.

    Science.gov (United States)

    Coons, Jane Ivy; Rusinko, Joseph

    2016-06-01

    The path interval distance accounts for global congruence between locally incongruent trees. We show that the path interval distance provides a lower bound for the nearest neighbor interchange distance. In contrast to the Robinson-Foulds distance, random pairs of trees are unlikely to be maximally distant from one another under the path interval distance. These features indicate that the path interval distance should play a role in phylogenomics where the comparison of trees on a fixed set of taxa is becoming increasingly important.

  20. Continuous-Discrete Path Integral Filtering

    Directory of Open Access Journals (Sweden)

    Bhashyam Balaji

    2009-08-01

    Full Text Available A summary of the relationship between the Langevin equation, Fokker-Planck-Kolmogorov forward equation (FPKfe and the Feynman path integral descriptions of stochastic processes relevant for the solution of the continuous-discrete filtering problem is provided in this paper. The practical utility of the path integral formula is demonstrated via some nontrivial examples. Specifically, it is shown that the simplest approximation of the path integral formula for the fundamental solution of the FPKfe can be applied to solve nonlinear continuous-discrete filtering problems quite accurately. The Dirac-Feynman path integral filtering algorithm is quite simple, and is suitable for real-time implementation.

  1. Private Giving Crowding Government Funding in Public Higher Education

    Directory of Open Access Journals (Sweden)

    G. Thomas Sav

    2010-01-01

    Full Text Available Problem statement: Private giving and government funding are critical revenue sources for public colleges and universities. If increased private giving reduces government funding, then that type and extent of crowding out carries important managerial and public policy implications. Approach: The study used a government funding reaction function and an instrumental variable approach to empirically estimate the potential for crowding out. Results: The study examined the extent to which private giving reduces or crowds out state government funding of public colleges and universities. Government free riding was at question and investigated to determine how active it is in terms of private donations partially or wholly displacing state government funding. The findings suggested that the rate of crowding out was 43% on the dollar. That compares to the 45% political substitution of the 1960’s but is much diminished from the 1980’s dollar for dollar crowding out. Those are aggregate comparisons for all public institutions. A disaggregated approach in this study additionally revealed that doctoral universities were victims of the same 43% crowd out but that at two other levels, master degree granting and associate degree granting colleges, there was the opposite effect of crowding in. Those colleges received state funding augmentations of 32-92% on their dollar of privately provided donations. Conclusion/Recommendations: The study’s finding of the existence of both crowding out and crowding in can carry important policy implications for college and university funding. Future managerial and public policy decision making should take that into account. However, political sustainability and economy wide and localized effects over time of crowding out and in could prove fruitful avenues of inquiry for future research.

  2. Confounding Issues in the Deadweight Loss of Gift-Giving

    OpenAIRE

    H. Kristl Davison; Bing, Mark N.; E. Bruce Hutchinson; Leila J. Pratt

    2008-01-01

    When a gift is given, someone other than the final consumer makes the consumption choice. Thus there is a possibility that the gift will not match the preferences of the receiver, i.e., the gift will represent a wise use of the money given the gift-giver's tastes but not necessarily a wise use of money given the recipient's tastes. In other words, gift giving can result in a deadweight loss. This paper addresses and clarifies the discrepancy between Waldfogel's (1993) finding of a deadweight ...

  3. Does friendship give us non-derivative partial reasons ?

    OpenAIRE

    Andrew Reisner

    2008-01-01

    One way to approach the question of whether there are non-derivative partial reasons of any kind is to give an account of what partial reasons are, and then to consider whether there are such reasons. If there are, then it is at least possible that there are partial reasons of friendship. It is this approach that will be taken here, and it produces several interesting results. The first is a point about the structure of partial reasons. It is at least a necessary condition of a reason’s being...

  4. Reluctant altruism and peer pressure in charitable giving

    Directory of Open Access Journals (Sweden)

    Diane Reyniers

    2013-01-01

    Full Text Available Subjects donate individually (control group or in pairs (treatment group. Those in pairs reveal their donation decision to each other. Average donations in the treatment group are significantly higher than in the control group. Paired subjects have the opportunity to revise their donation decision after discussion. Pair members shift toward each others' initial decisions. Subjects are happier with their decision when their donations are larger, but those in pairs are less happy, controlling for amount donated. These findings suggest reluctant altruism due to peer pressure in charitable giving.

  5. A Childhood Rich in Culture Gives a Socioeconomic Bonus

    DEFF Research Database (Denmark)

    Austring, Bennye Düranc

    2015-01-01

    Artiklen ridser den nyeste forskning op inden for feltet 'art rich learning', altså æstetiske læreprocesser af god kvalitet. In the book ”Art and Culture Give Children a Life that Works” 60 (Danish and non-Danish) experts, practitioners, artists and several Ministers from the Danish Government...... focus on the significance of Art and Culture for children. The book provides lots of inspiration for teachers, pedagogues and cultural mediators and contains many examples of specific cultural activities, links and bibliographic references....

  6. Adaptive-feedback control algorithm.

    Science.gov (United States)

    Huang, Debin

    2006-06-01

    This paper is motivated by giving the detailed proofs and some interesting remarks on the results the author obtained in a series of papers [Phys. Rev. Lett. 93, 214101 (2004); Phys. Rev. E 71, 037203 (2005); 69, 067201 (2004)], where an adaptive-feedback algorithm was proposed to effectively stabilize and synchronize chaotic systems. This note proves in detail the strictness of this algorithm from the viewpoint of mathematics, and gives some interesting remarks for its potential applications to chaos control & synchronization. In addition, a significant comment on synchronization-based parameter estimation is given, which shows some techniques proposed in literature less strict and ineffective in some cases.

  7. Giving blood: a new role for CD40 in tumorigenesis.

    Science.gov (United States)

    Bergmann, Stephan; Pandolfi, Pier Paolo

    2006-10-30

    CD40 was initially identified as a receptor expressed by B cells that is crucial for inducing an effective adaptive immune response. CD40 was subsequently shown to be expressed by endothelial cells and to promote angiogenesis. New data now show that in tumor-prone transgenic mice, CD40-mediated neovascularization is essential for early stage tumorigenicity. This suggests, at least in this mouse model, that CD40 has an important role in the angiogenic process that is coupled to carcinogenesis, a finding that could lead to novel therapeutic opportunities.

  8. Dictator Game Giving: The Importance of Descriptive versus Injunctive Norms.

    Science.gov (United States)

    Raihani, Nichola J; McAuliffe, Katherine

    2014-01-01

    Human behaviour is influenced by social norms but norms can entail two types of information. Descriptive norms refer to what others do in this context, while injunctive norms refer to what ought to be done to ensure social approval. In many real-world situations these norms are often presented concurrently meaning that their independent effects on behaviour are difficult to establish. Here we used an online Dictator Game to test how descriptive and injunctive norms would influence dictator donations when presented independently of one another. In addition, we varied the cost of complying with the norm: By stating that $0.20 or $0.50 cent donations from a $1 stake were normal or suggested, respectively. Specifying a higher target amount was associated with increased mean donation size. In contrast to previous studies, descriptive norms did not seem to influence giving behaviour in this context, whereas injunctive norms were associated with increased likelihood to give at least the target amount to the partner. This raises the question of whether injunctive norms might be more effective than descriptive norms at promoting prosocial behaviour in other settings.

  9. Organometallic chemistry meets crystal engineering to give responsive crystalline materials.

    Science.gov (United States)

    Bacchi, A; Pelagatti, P

    2016-01-25

    Dynamically porous crystalline materials have been obtained by engineering organometallic molecules. This feature article deals with organometallic wheel-and-axle compounds, molecules with two relatively bulky groups (wheels) connected by a linear spacer. The wheels are represented by half-sandwich Ru(ii) moieties, while the spacer can be covalent or supramolecular in character. Covalent spacers are obtained using divergent bidentate ligands connecting two [(arene)RuX2] groups. Supramolecular spacers are instead obtained by exploiting the dimerization of COOH or C(O)NH2 groups appended to N-based ligands. A careful choice of ligand functional groups and X ligands leads to the isolation of crystalline materials with remarkable host-guest properties, evidenced by the possibility of reversibly capturing/releasing volatile guests through heterogenous solid-gas reactions. Structural correlations between the crystalline arrangement of the apohost and the host-guest compounds allow us to envisage the structural path followed by the system during the exchange processes.

  10. The take and give between retrotransposable elements and their hosts.

    Science.gov (United States)

    Beauregard, Arthur; Curcio, M Joan; Belfort, Marlene

    2008-01-01

    Retrotransposons mobilize via RNA intermediates and usually carry with them the agent of their mobility, reverse transcriptase. Retrotransposons are streamlined, and therefore rely on host factors to proliferate. However, retrotransposons are exposed to cellular forces that block their paths. For this review, we have selected for our focus elements from among target-primed (TP) retrotransposons, also called non-LTR retrotransposons, and extrachromosomally-primed (EP) retrotransposons, also called LTR retrotransposons. The TP retrotransposons considered here are group II introns, LINEs and SINEs, whereas the EP elements considered are the Ty and Tf retrotransposons, with a brief comparison to retroviruses. Recurring themes for these elements, in hosts ranging from bacteria to humans, are tie-ins of the retrotransposons to RNA metabolism, DNA replication and repair, and cellular stress. Likewise, there are parallels among host-cell defenses to combat rampant retrotransposon spread. The interactions between the retrotransposon and the host, and their coevolution to balance the tension between retrotransposon proliferation and host survival, form the basis of this review.

  11. Two Paths Diverged: Exploring Trajectories, Protocols, and Dynamic Phases

    Science.gov (United States)

    Gingrich, Todd Robert

    Using tools of statistical mechanics, it is routine to average over the distribution of microscopic configurations to obtain equilibrium free energies. These free energies teach us about the most likely molecular arrangements and the probability of observing deviations from the norm. Frequently, it is necessary to interrogate the probability not just of static arrangements, but of dynamical events, in which case analogous statistical mechanical tools may be applied to study the distribution of molecular trajectories. Numerical study of these trajectory spaces requires algorithms which efficiently sample the possible trajectories. We study in detail one such Monte Carlo algorithm, transition path sampling, and use a non- equilibrium statistical mechanical perspective to illuminate why the algorithm cannot easily be adapted to study some problems involving long-timescale dynamics. Algorithmically generating highly-correlated trajectories, a necessity for transition path sampling, grows exponentially more challenging for longer trajectories unless the dynamics is strongly-guided by the "noise history", the sequence of random numbers representing the noise terms in the stochastic dynamics. Langevin dynamics of Weeks-Chandler-Andersen (WCA) particles in two dimensions lacks this strong noise guidance, so it is challenging to use transition path sampling to study rare dynamical events in long trajectories of WCA particles. The spin flip dynamics of a two-dimensional Ising model, on the other hand, can be guided by the noise history to achieve efficient path sampling. For systems that can be efficiently sampled with path sampling, we show that it is possible to simultaneously sample both the paths and the (potentially vast) space of non-equilibrium protocols to efficiently learn how rate constants vary with protocols and to identify low-dissipation protocols. When high-dimensional molecular dynamics can be coarse-grained and represented by a simplified dynamics on a low

  12. Perturbative Methods in Path Integration

    Science.gov (United States)

    Johnson-Freyd, Theodore Paul

    This dissertation addresses a number of related questions concerning perturbative "path" integrals. Perturbative methods are one of the few successful ways physicists have worked with (or even defined) these infinite-dimensional integrals, and it is important as mathematicians to check that they are correct. Chapter 0 provides a detailed introduction. We take a classical approach to path integrals in Chapter 1. Following standard arguments, we posit a Feynman-diagrammatic description of the asymptotics of the time-evolution operator for the quantum mechanics of a charged particle moving nonrelativistically through a curved manifold under the influence of an external electromagnetic field. We check that our sum of Feynman diagrams has all desired properties: it is coordinate-independent and well-defined without ultraviolet divergences, it satisfies the correct composition law, and it satisfies Schrodinger's equation thought of as a boundary-value problem in PDE. Path integrals in quantum mechanics and elsewhere in quantum field theory are almost always of the shape ∫ f es for some functions f (the "observable") and s (the "action"). In Chapter 2 we step back to analyze integrals of this type more generally. Integration by parts provides algebraic relations between the values of ∫ (-) es for different inputs, which can be packaged into a Batalin--Vilkovisky-type chain complex. Using some simple homological perturbation theory, we study the version of this complex that arises when f and s are taken to be polynomial functions, and power series are banished. We find that in such cases, the entire scheme-theoretic critical locus (complex points included) of s plays an important role, and that one can uniformly (but noncanonically) integrate out in a purely algebraic way the contributions to the integral from all "higher modes," reducing ∫ f es to an integral over the critical locus. This may help explain the presence of analytic continuation in questions like the

  13. The different paths to entropy

    CERN Document Server

    Benguigui, L

    2012-01-01

    In order to undestand how the complex concept of entropy emerged,we propose a trip towards the past reviewing the works of Clausius, Boltzmann, Gibbs and Planck. In particular, since the Gibbs's work is not very well known, we present a detailed analysis, recalling the three definitions of the entropy that Gibbs gives. May be one of the most important aspect of the entropy is to see it as a thermodynamic potential like the other thermodynamic potentials as proposed by Callen. We close with some remarks on entropy and irreversibility.

  14. Adaptive security systems -- Combining expert systems with adaptive technologies

    Energy Technology Data Exchange (ETDEWEB)

    Argo, P.; Loveland, R.; Anderson, K. [and others

    1997-09-01

    The Adaptive Multisensor Integrated Security System (AMISS) uses a variety of computational intelligence techniques to reason from raw sensor data through an array of processing layers to arrive at an assessment for alarm/alert conditions based on human behavior within a secure facility. In this paper, the authors give an overview of the system and briefly describe some of the major components of the system. This system is currently under development and testing in a realistic facility setting.

  15. Joint modeling of constrained path enumeration and path choice behavior: a semi-compensatory approach

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2010-01-01

    A behavioural and a modelling framework are proposed for representing route choice from a path set that satisfies travellers’ spatiotemporal constraints. Within the proposed framework, travellers’ master sets are constructed by path generation, consideration sets are delimited according to spatio...... constraints are related to travellers’ socio-economic characteristics and that path choice is related to minimizing time and avoiding congestion....

  16. White Noise Path Integrals in Stochastic Neurodynamics

    Science.gov (United States)

    Carpio-Bernido, M. Victoria; Bernido, Christopher C.

    2008-06-01

    The white noise path integral approach is used in stochastic modeling of neural activity, where the primary dynamical variables are the relative membrane potentials, while information on transmembrane ionic currents is contained in the drift coefficient. The white noise path integral allows a natural framework and can be evaluated explicitly to yield a closed form for the conditional probability density.

  17. Robot path planning using genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents a strategy for soccer robot path planning using genetic algorithms for which, real number coding method is used, to overcome the defects of binary coding method, and the double crossover operation a dopted, to avoid the common defect of early convergence and converge faster than the standard genetic algo rithms concludes from simulation results that the method is effective for robot path planning.

  18. Graphic method for analyzing common path interferometers

    DEFF Research Database (Denmark)

    Glückstad, J.

    1998-01-01

    Common path interferometers are widely used for visualizing phase disturbances and fluid flows. They are attractive because of the inherent simplicity and robustness in the setup. A graphic method will be presented for analyzing and optimizing filter parameters in common path interferometers....

  19. Consistent Partial Least Squares Path Modeling

    NARCIS (Netherlands)

    Dijkstra, Theo K.; Henseler, Jörg

    2015-01-01

    This paper resumes the discussion in information systems research on the use of partial least squares (PLS) path modeling and shows that the inconsistency of PLS path coefficient estimates in the case of reflective measurement can have adverse consequences for hypothesis testing. To remedy this, the

  20. Multi-block and path modelling procedures

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2008-01-01

    The author has developed a unified theory of path and multi-block modelling of data. The data blocks are arranged in a directional path. Each data block can lead to one or more data blocks. It is assumed that there is given a collection of input data blocks. Each of them is supposed to describe one...

  1. The Path of Carbon in Photosynthesis VI.

    Science.gov (United States)

    Calvin, M.

    1949-06-30

    This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity within the compounds is described.

  2. Two Generations of Path Dependence in Economics?

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2010-01-01

    Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences – primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

  3. Cost allocation in shortest path games

    NARCIS (Netherlands)

    Voorneveld, M.; Grahn, S.

    2001-01-01

    A class of cooperative games arising from shortest path problems is dened These shortest path games are shown to be totally balanced and allow a population monotonic allocation scheme Possible methods for obtaining core elements are indicated rst by relating to the allocation rules in taxation and b

  4. Hedonic "adaptation"

    Directory of Open Access Journals (Sweden)

    Paul Rozin

    2008-02-01

    Full Text Available People live in a world in which they are surrounded by potential disgust elicitors such as ``used'' chairs, air, silverware, and money as well as excretory activities. People function in this world by ignoring most of these, by active avoidance, reframing, or adaptation. The issue is particularly striking for professions, such as morticians, surgeons, or sanitation workers, in which there is frequent contact with major disgust elicitors. In this study, we study the ``adaptation'' process to dead bodies as disgust elicitors, by measuring specific types of disgust sensitivity in medical students before and after they have spent a few months dissecting a cadaver. Using the Disgust Scale, we find a significant reduction in disgust responses to death and body envelope violation elicitors, but no significant change in any other specific type of disgust. There is a clear reduction in discomfort at touching a cold dead body, but not in touching a human body which is still warm after death.

  5. Adaptation Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Huq, Saleemul

    2011-11-15

    Efforts to help the world's poor will face crises in coming decades as climate change radically alters conditions. Action Research for Community Adapation in Bangladesh (ARCAB) is an action-research programme on responding to climate change impacts through community-based adaptation. Set in Bangladesh at 20 sites that are vulnerable to floods, droughts, cyclones and sea level rise, ARCAB will follow impacts and adaptation as they evolve over half a century or more. National and international 'research partners', collaborating with ten NGO 'action partners' with global reach, seek knowledge and solutions applicable worldwide. After a year setting up ARCAB, we share lessons on the programme's design and move into our first research cycle.

  6. Inked Careers: Tattooing Professional Paths

    Directory of Open Access Journals (Sweden)

    Gabriela DeLuca

    2016-12-01

    Full Text Available The concept of career has an interdisciplinary and historical constitution, which includes persons, groups, organizations and society. Given that, we aim to deepen the interactionist notion of career from the understanding of a deviant path, supported by a theory and a method appropriated to the cited call for interdisciplinary approaches. Dilemmas (Hughes, 1958 and conflicts (Hughes, 1937 emerged as important analytical categories. Although necessary, these two concepts were not sufficient to contemplate analyses in their entirety. For this reason we conceptualized a third possibility of controversy during a career: the inquiries. The study followed the Narrative method to analyze objective and subjective changes during a tattoo artist’s career through interviews and informal conversations carried out over 22 months. The discussion presents three main contributions. Theoretically, a new understanding of the concept of careers, linking past, present and future and the idea of non-linearity of experienced and envisioned careers. Methodologically, suggesting orientations for future career studies such as the use of turning points as a methodological tool and the investigation of deviant fields. Finally, our defense of the interactionist perspective as suitable for career studies, since it allows the investigation of deviant elements.

  7. Precision Cleaning - Path to Premier

    Science.gov (United States)

    Mackler, Scott E.

    2008-01-01

    ITT Space Systems Division s new Precision Cleaning facility provides critical cleaning and packaging of aerospace flight hardware and optical payloads to meet customer performance requirements. The Precision Cleaning Path to Premier Project was a 2007 capital project and is a key element in the approved Premier Resource Management - Integrated Supply Chain Footprint Optimization Project. Formerly precision cleaning was located offsite in a leased building. A new facility equipped with modern precision cleaning equipment including advanced process analytical technology and improved capabilities was designed and built after outsourcing solutions were investigated and found lacking in ability to meet quality specifications and schedule needs. SSD cleans parts that can range in size from a single threaded fastener all the way up to large composite structures. Materials that can be processed include optics, composites, metals and various high performance coatings. We are required to provide verification to our customers that we have met their particulate and molecular cleanliness requirements and we have that analytical capability in this new facility. The new facility footprint is approximately half the size of the former leased operation and provides double the amount of throughput. Process improvements and new cleaning equipment are projected to increase 1st pass yield from 78% to 98% avoiding $300K+/yr in rework costs. Cost avoidance of $350K/yr will result from elimination of rent, IT services, transportation, and decreased utility costs. Savings due to reduced staff expected to net $4-500K/yr.

  8. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  9. Adaptive Multilevel Monte Carlo Simulation

    KAUST Repository

    Hoel, H

    2011-08-23

    This work generalizes a multilevel forward Euler Monte Carlo method introduced in Michael B. Giles. (Michael Giles. Oper. Res. 56(3):607–617, 2008.) for the approximation of expected values depending on the solution to an Itô stochastic differential equation. The work (Michael Giles. Oper. Res. 56(3):607– 617, 2008.) proposed and analyzed a forward Euler multilevelMonte Carlo method based on a hierarchy of uniform time discretizations and control variates to reduce the computational effort required by a standard, single level, Forward Euler Monte Carlo method. This work introduces an adaptive hierarchy of non uniform time discretizations, generated by an adaptive algorithmintroduced in (AnnaDzougoutov et al. Raùl Tempone. Adaptive Monte Carlo algorithms for stopped diffusion. In Multiscale methods in science and engineering, volume 44 of Lect. Notes Comput. Sci. Eng., pages 59–88. Springer, Berlin, 2005; Kyoung-Sook Moon et al. Stoch. Anal. Appl. 23(3):511–558, 2005; Kyoung-Sook Moon et al. An adaptive algorithm for ordinary, stochastic and partial differential equations. In Recent advances in adaptive computation, volume 383 of Contemp. Math., pages 325–343. Amer. Math. Soc., Providence, RI, 2005.). This form of the adaptive algorithm generates stochastic, path dependent, time steps and is based on a posteriori error expansions first developed in (Anders Szepessy et al. Comm. Pure Appl. Math. 54(10):1169– 1214, 2001). Our numerical results for a stopped diffusion problem, exhibit savings in the computational cost to achieve an accuracy of ϑ(TOL),from(TOL−3), from using a single level version of the adaptive algorithm to ϑ(((TOL−1)log(TOL))2).

  10. Dynamic coding of goal-directed paths by orbital prefrontal cortex.

    Science.gov (United States)

    Young, James J; Shapiro, Matthew L

    2011-04-20

    Adapting successfully to new situations relies on integrating memory of similar circumstances with the outcomes of past actions. Here, we tested how reward history and recent memory influenced coding by orbital prefrontal cortex (OFC) neurons. Rats were trained to find food in plus maze tasks that required both the OFC and the hippocampus, and unit activity was recorded during stable performance, reversal learning, and strategy switching. OFC firing distinguished different rewarded paths, journeys from a start arm to a goal arm. Activity of individual cells and the population correlated with performance as rats learned newly rewarded outcomes. Activity was similar during reversal, an OFC-dependent task, and strategy switching, an OFC-independent task, suggesting that OFC associates information about paths and outcomes both when it is required for performance and when it is not. Path-selective OFC cells fired differently during overlapping journeys that led to different goals or from different starts, resembling journey-dependent coding by hippocampal neurons. Local field potentials (LFPs) recorded simultaneously in the OFC and the hippocampus oscillated coherently in the theta band (5-12 Hz) during stable performance. LFP coherence diminished when rats adapted to altered reward contingencies and followed different paths. Thus, OFC neurons appear to participate in a distributed network including the hippocampus that associates spatial paths, recent memory, and integrated reward history.

  11. Critical Review of Path Integral Formulation

    CERN Document Server

    Fujita, Takehisa

    2008-01-01

    The path integral formulation in quantum mechanics corresponds to the first quantization since it is just to rewrite the quantum mechanical amplitude into many dimensional integrations over discretized coordinates $x_n$. However, the path integral expression cannot be connected to the dynamics of classical mechanics, even though, superficially, there is some similarity between them. Further, the field theory path integral in terms of many dimensional integrations over fields does not correspond to the field quantization. We clarify the essential difference between Feynman's original formulation of path integral in QED and the modern version of the path integral method prevailing in lattice field theory calculations, and show that the former can make a correct second quantization while the latter cannot quantize fields at all and its physical meaning is unknown.

  12. Feynman Path Integrals Over Entangled States

    CERN Document Server

    Green, A G; Keeling, J; Simon, S H

    2016-01-01

    The saddle points of a conventional Feynman path integral are not entangled, since they comprise a sequence of classical field configurations. We combine insights from field theory and tensor networks by constructing a Feynman path integral over a sequence of matrix product states. The paths that dominate this path integral include some degree of entanglement. This new feature allows several insights and applications: i. A Ginzburg-Landau description of deconfined phase transitions. ii. The emergence of new classical collective variables in states that are not adiabatically continuous with product states. iii. Features that are captured in product-state field theories by proliferation of instantons are encoded in perturbative fluctuations about entangled saddles. We develop a general formalism for such path integrals and a couple of simple examples to illustrate their utility.

  13. Association Analysis of Alumni Giving: A Formal Concept Analysis

    Science.gov (United States)

    Hashemi, Ray R.; Le Blanc, Louis A.; Bahar, Mahmood; Traywick, Bryan

    A large sample (initially 33,000 cases representing a ten percent trial) of university alumni giving records for a large public university in the southwestern United States are analyzed by Formal Concept Analysis (FCA). This likely represents the initially attempt to perform analysis of such data by means of a machine learing technique. The variables employed include the gift amount to the university foundation (UF) as well as traditional demographic variables such as year of graduation, gender, ethnicity, marital status, etc. The UF serves as one of the institution's non-profit, fund-raising organizations. It pursues substantial gifts that are designated for the educational or leadership programs of the giver's choice. Although they process gifts of all sizes, the UF focus is on major gifts and endowments.

  14. Paedomorphic facial expressions give dogs a selective advantage.

    Directory of Open Access Journals (Sweden)

    Bridget M Waller

    Full Text Available How wolves were first domesticated is unknown. One hypothesis suggests that wolves underwent a process of self-domestication by tolerating human presence and taking advantage of scavenging possibilities. The puppy-like physical and behavioural traits seen in dogs are thought to have evolved later, as a byproduct of selection against aggression. Using speed of selection from rehoming shelters as a proxy for artificial selection, we tested whether paedomorphic features give dogs a selective advantage in their current environment. Dogs who exhibited facial expressions that enhance their neonatal appearance were preferentially selected by humans. Thus, early domestication of wolves may have occurred not only as wolf populations became tamer, but also as they exploited human preferences for paedomorphic characteristics. These findings, therefore, add to our understanding of early dog domestication as a complex co-evolutionary process.

  15. The Effect of Giving Feedback to Students' Writing

    Directory of Open Access Journals (Sweden)

    Mochamad Zainuddin

    2004-01-01

    Full Text Available Although writing is as important as other skills such as listening, speaking, and reading, it needs more special attention. In order to write well, students need a long process to learn to write and they need continous feedback. The aim of this article is to know whether giving feedback to students' writing has a significant effect or not. Two groups of students, experimental and control, were involved. The compositions of the first group were given feedback, while those of the second group were not given feedback. The study shows that provision of feedback improves student's writing. In light of the result of the study, it is recommended that teachers provide feedback on students' writing.

  16. What are the impacts of giving up the driver license?

    DEFF Research Database (Denmark)

    Siren, Anu Kristiina; Haustein, Sonja

    Objectives: Driving cessation is a gradual process, where driver’s self-regulation plays an important role. Age-based license renewal procedures may interfere with this process and trigger premature driving cessation. The present study compares drivers aged 69 years at the baseline who either...... renewed their driver’s license (“renewers”) or did not (“non-renewers”) over a two-year period. Methods: Data were collected by interviewing a sample of older Danish people in 2009 (n = 1,792) and in 2012 (n = 863). The standardized interviews covered respondents’ background information, health and well......-being, and modal choices and transportation patterns. Results: Non-renewers had poorer health already at baseline. However, they did become more dependent on others in their out-of-home activities after giving up their license. In travel frequency, neither the differences between renewers and non-renewers nor...

  17. Giving Students the Power to Engage with Learning

    Science.gov (United States)

    Cochran, Kathryn F.; Reinsvold, Lori A.; Hess, Chelsie A.

    2016-11-01

    This critical discourse analysis study identifies and describes power relationships in elementary classrooms that support science engagement by providing students time to think, ask questions, and find their voices to talk about subject matter. The first analyses involved identification and description of classroom episodes showing high levels of student power and engagement associated with learning science. Classroom episodes were grouped into seven power patterns: use of questions, teacher sharing authority, giving students credit for knowledge, legitimate digressions, enhanced feedback, and writing opportunities. The second analyses documented the manner in which these patterns formed more complex classroom engagement processes called power clusters. These examples further our understanding of the dynamics of classroom discourse and the relationships between student power and engagement in subject matter.

  18. Nutrition and the brain: what advice should we give?

    Science.gov (United States)

    Cooper, James K

    2014-09-01

    The knowledge base of nutrition and the brain is steadily expanding. Much of the research is aimed at ways to protect the brain from damage. In adults, the major causes of brain damage are aging and dementia. The most prominent dementia, and the condition that grabs the most public attention, is Alzheimer's disease. The assumption in the field is that possibly some change in nutrition could protect the brain and prevent, delay, or minimize Alzheimer's disease damage. Presented here is a framework for understanding the implications of this research. There is a gap between publishing research results and change in public nutrition behavior. Several influencing elements intervene. These include regulatory agencies and all the organizations and people who advise the public, all with their own perspectives. In considering what advice to give, advisors may consider effectiveness, research model, persuasiveness, and risks, among other factors. Advice about nutrition and Alzheimer's disease today requires several caveats.

  19. GIVE VOICES TO SILENT LEARNERS IN SPEAKING CLASS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    It is commonly experienced by teachers that they meet silent learners in speaking class,especiallyin an EFL setting at the tertiary level in China.This paper attempts to diagnose the problems inthe current curriculum,curriculum materials and teaching methods used to teach the productiveskill of speaking,which are supposed to be the direct cause of students in"losing their voices",Itbegins with a brief description of the teaching and learning situation in a teachers’ college which isalso typical at other tertiary levels as well.Concrete examples of modification to the teaching ofthe skill are provided with the hope to give back"voices"to the silent students in speaking class.

  20. When natural selection gives gene function the cold shoulder.

    Science.gov (United States)

    Cutter, Asher D; Jovelin, Richard

    2015-11-01

    It is tempting to invoke organismal selection as perpetually optimizing the function of any given gene. However, natural selection can drive genic functional change without improvement of biochemical activity, even to the extinction of gene activity. Detrimental mutations can creep in owing to linkage with other selectively favored loci. Selection can promote functional degradation, irrespective of genetic drift, when adaptation occurs by loss of gene function. Even stabilizing selection on a trait can lead to divergence of the underlying molecular constituents. Selfish genetic elements can also proliferate independent of any functional benefits to the host genome. Here we review the logic and evidence for these diverse processes acting in genome evolution. This collection of distinct evolutionary phenomena - while operating through easily understandable mechanisms - all contribute to the seemingly counterintuitive notion that maintenance or improvement of a gene's biochemical function sometimes do not determine its evolutionary fate.

  1. Real-time optical path control method that utilizes multiple support vector machines for traffic prediction

    Science.gov (United States)

    Kawase, Hiroshi; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

    2016-02-01

    An effective solution to the continuous Internet traffic expansion is to offload traffic to lower layers such as the L2 or L1 optical layers. One possible approach is to introduce dynamic optical path operations such as adaptive establishment/tear down according to traffic variation. Path operations cannot be done instantaneously; hence, traffic prediction is essential. Conventional prediction techniques need optimal parameter values to be determined in advance by averaging long-term variations from the past. However, this does not allow adaptation to the ever-changing short-term variations expected to be common in future networks. In this paper, we propose a real-time optical path control method based on a machinelearning technique involving support vector machines (SVMs). A SVM learns the most recent traffic characteristics, and so enables better adaptation to temporal traffic variations than conventional techniques. The difficulty lies in determining how to minimize the time gap between optical path operation and buffer management at the originating points of those paths. The gap makes the required learning data set enormous and the learning process costly. To resolve the problem, we propose the adoption of multiple SVMs running in parallel, trained with non-overlapping subsets of the original data set. The maximum value of the outputs of these SVMs will be the estimated number of necessary paths. Numerical experiments prove that our proposed method outperforms a conventional prediction method, the autoregressive moving average method with optimal parameter values determined by Akaike's information criterion, and reduces the packet-loss ratio by up to 98%.

  2. Regularization Paths for Least Squares Problems with Generalized $\\ell_1$ Penalties

    CERN Document Server

    Tibshirani, Ryan J

    2010-01-01

    We present a path algorithm for least squares problems with generalized $\\ell_1$ penalties. This includes as a special case the lasso and fused lasso problems. The algorithm is based on solving the (equivalent) Lagrange dual problem, an approach which offers both a computational advantage and an interesting geometric interpretation of the solution path. Using insights gathered from the dual formulation, we study degrees of freedom for the generalized problem, and develop an unbiased estimate of the degrees of freedom of the fused lasso fit. Our approach bears similarities to least angle regression (LARS), and a simple modification to our method gives the LARS procedure exactly.

  3. Synthesis of Spherical 4R Mechanism for Path Generation using Differential Evolution

    CERN Document Server

    Penunuri, F; Villanueva, C; Cruz-Villar, Carlos A

    2011-01-01

    The problem of path generation for the spherical 4R mechanism is solved using the Differential Evolution (DE) algorithm. Formulas for the spherical geodesics are employed in order to obtain the parametric equation for the trajectory of the mechanism end-effector. Direct optimization of the objective function gives solution to the path generation task without prescribed timing. Therefore, there is no need to separate this task into two stages and then proceed to the optimization. Moreover, the order defect problem can be solved without difficulty by means of manipulations of the individuals in the DE algorithm. Two examples of optimum synthesis showing the simplicity and effectiveness of the approach are included.

  4. Path statistics, memory, and coarse-graining of continuous-time random walks on networks.

    Science.gov (United States)

    Manhart, Michael; Kion-Crosby, Willow; Morozov, Alexandre V

    2015-12-01

    Continuous-time random walks (CTRWs) on discrete state spaces, ranging from regular lattices to complex networks, are ubiquitous across physics, chemistry, and biology. Models with coarse-grained states (for example, those employed in studies of molecular kinetics) or spatial disorder can give rise to memory and non-exponential distributions of waiting times and first-passage statistics. However, existing methods for analyzing CTRWs on complex energy landscapes do not address these effects. Here we use statistical mechanics of the nonequilibrium path ensemble to characterize first-passage CTRWs on networks with arbitrary connectivity, energy landscape, and waiting time distributions. Our approach can be applied to calculating higher moments (beyond the mean) of path length, time, and action, as well as statistics of any conservative or non-conservative force along a path. For homogeneous networks, we derive exact relations between length and time moments, quantifying the validity of approximating a continuous-time process with its discrete-time projection. For more general models, we obtain recursion relations, reminiscent of transfer matrix and exact enumeration techniques, to efficiently calculate path statistics numerically. We have implemented our algorithm in PathMAN (Path Matrix Algorithm for Networks), a Python script that users can apply to their model of choice. We demonstrate the algorithm on a few representative examples which underscore the importance of non-exponential distributions, memory, and coarse-graining in CTRWs.

  5. Statistical reliability and path diversity based PageRank algorithm improvements

    CERN Document Server

    Hong, Dohy

    2012-01-01

    In this paper we present new improvement ideas of the original PageRank algorithm. The first idea is to introduce an evaluation of the statistical reliability of the ranking score of each node based on the local graph property and the second one is to introduce the notion of the path diversity. The path diversity can be exploited to dynamically modify the increment value of each node in the random surfer model or to dynamically adapt the damping factor. We illustrate the impact of such modifications through examples and simple simulations.

  6. A genome survey of Moniliophthora perniciosa gives new insights into Witches' Broom Disease of cacao

    Directory of Open Access Journals (Sweden)

    Bailey Bryan A

    2008-11-01

    Full Text Available Abstract Background The basidiomycete fungus Moniliophthora perniciosa is the causal agent of Witches' Broom Disease (WBD in cacao (Theobroma cacao. It is a hemibiotrophic pathogen that colonizes the apoplast of cacao's meristematic tissues as a biotrophic pathogen, switching to a saprotrophic lifestyle during later stages of infection. M. perniciosa, together with the related species M. roreri, are pathogens of aerial parts of the plant, an uncommon characteristic in the order Agaricales. A genome survey (1.9× coverage of M. perniciosa was analyzed to evaluate the overall gene content of this phytopathogen. Results Genes encoding proteins involved in retrotransposition, reactive oxygen species (ROS resistance, drug efflux transport and cell wall degradation were identified. The great number of genes encoding cytochrome P450 monooxygenases (1.15% of gene models indicates that M. perniciosa has a great potential for detoxification, production of toxins and hormones; which may confer a high adaptive ability to the fungus. We have also discovered new genes encoding putative secreted polypeptides rich in cysteine, as well as genes related to methylotrophy and plant hormone biosynthesis (gibberellin and auxin. Analysis of gene families indicated that M. perniciosa have similar amounts of carboxylesterases and repertoires of plant cell wall degrading enzymes as other hemibiotrophic fungi. In addition, an approach for normalization of gene family data using incomplete genome data was developed and applied in M. perniciosa genome survey. Conclusion This genome survey gives an overview of the M. perniciosa genome, and reveals that a significant portion is involved in stress adaptation and plant necrosis, two necessary characteristics for a hemibiotrophic fungus to fulfill its infection cycle. Our analysis provides new evidence revealing potential adaptive traits that may play major roles in the mechanisms of pathogenicity in the M. perniciosa

  7. Adaptive Routing Algorithm for MANET:TERMITE

    Directory of Open Access Journals (Sweden)

    Sharvani G S

    2009-12-01

    Full Text Available Mobile Ad hoc network consists of a set of mobile nodes. This network does not have anyinfrastructure or central administration, hence it is called infrastructure less network. As the nodes aremobile, it is very difficult to find the path between two end points. This paper presents a solution forfinding path between nodes in mobile ad hoc network. Termite is an innovative algorithm for packetrouting in communication networks. Termite is an adaptive, distributed, mobile-agents-based algorithmwhich was inspired by recent work on the ant colony metaphor. According to this algorithm, a group ofmobile agents (or artificial termites build paths between pair of nodes; exploring the networkconcurrently and exchanging obtained information to update the routing tables. Some of the parametersused to evaluate its performance are packet delays and throughput. The results of this algorithm showsbetter throughput as compared to existing algorithms. So, Termite algorithm is a promising alternativefor routing of data in commercial networks.

  8. Hybridizing Particle Swarm Optimization and Differential Evolution for the Mobile Robot Global Path Planning

    Directory of Open Access Journals (Sweden)

    Biwei Tang

    2016-05-01

    Full Text Available Global path planning is a challenging issue in the filed of mobile robotics due to its complexity and the nature of nondeterministic polynomial-time hard (NP-hard. Particle swarm optimization (PSO has gained increasing popularity in global path planning due to its simplicity and high convergence speed. However, since the basic PSO has difficulties balancing exploration and exploitation, and suffers from stagnation, its efficiency in solving global path planning may be restricted. Aiming at overcoming these drawbacks and solving the global path planning problem efficiently, this paper proposes a hybrid PSO algorithm that hybridizes PSO and differential evolution (DE algorithms. To dynamically adjust the exploration and exploitation abilities of the hybrid PSO, a novel PSO, the nonlinear time-varying PSO (NTVPSO, is proposed for updating the velocities and positions of particles in the hybrid PSO. In an attempt to avoid stagnation, a modified DE, the ranking-based self adaptive DE (RBSADE, is developed to evolve the personal best experience of particles in the hybrid PSO. The proposed algorithm is compared with four state-of-the-art evolutionary algorithms. Simulation results show that the proposed algorithm is highly competitive in terms of path optimality and can be considered as a vital alternative for solving global path planning.

  9. Speed-up hyperspheres homotopic path tracking algorithm for PWL circuits simulations.

    Science.gov (United States)

    Ramirez-Pinero, A; Vazquez-Leal, H; Jimenez-Fernandez, V M; Sedighi, H M; Rashidi, M M; Filobello-Nino, U; Castaneda-Sheissa, R; Huerta-Chua, J; Sarmiento-Reyes, L A; Laguna-Camacho, J R; Castro-Gonzalez, F

    2016-01-01

    In the present work, we introduce an improved version of the hyperspheres path tracking method adapted for piecewise linear (PWL) circuits. This enhanced version takes advantage of the PWL characteristics from the homotopic curve, achieving faster path tracking and improving the performance of the homotopy continuation method (HCM). Faster computing time allows the study of complex circuits with higher complexity; the proposed method also decrease, significantly, the probability of having a diverging problem when using the Newton-Raphson method because it is applied just twice per linear region on the homotopic path. Equilibrium equations of the studied circuits are obtained applying the modified nodal analysis; this method allows to propose an algorithm for nonlinear circuit analysis. Besides, a starting point criteria is proposed to obtain better performance of the HCM and a technique for avoiding the reversion phenomenon is also proposed. To prove the efficiency of the path tracking method, several cases study with bipolar (BJT) and CMOS transistors are provided. Simulation results show that the proposed approach can be up to twelve times faster than the original path tracking method and also helps to avoid several reversion cases that appears when original hyperspheres path tracking scheme was employed.

  10. UAV feasible path planning based on disturbed fluid and trajectory propagation

    Directory of Open Access Journals (Sweden)

    Yao Peng

    2015-08-01

    Full Text Available In this paper, a novel algorithm based on disturbed fluid and trajectory propagation is developed to solve the three-dimensional (3-D path planning problem of unmanned aerial vehicle (UAV in static environment. Firstly, inspired by the phenomenon of streamlines avoiding obstacles, the algorithm based on disturbed fluid is developed and broadened. The effect of obstacles on original fluid field is quantified by the perturbation matrix, where the tangential matrix is first introduced. By modifying the original flow field, the modified one is then obtained, where the streamlines can be regarded as planned paths. And the path proves to avoid all obstacles smoothly and swiftly, follow the shape of obstacles effectively and reach the destination eventually. Then, by considering the kinematics and dynamics equations of UAV, the method called trajectory propagation is adopted to judge the feasibility of the path. If the planned path is unfeasible, repulsive and tangential parameters in the perturbation matrix will be adjusted adaptively based on the resolved state variables of UAV. In most cases, a flyable path can be obtained eventually. Simulation results demonstrate the effectiveness of this method.

  11. Nonholonomic catheter path reconstruction using electromagnetic tracking

    Science.gov (United States)

    Lugez, Elodie; Sadjadi, Hossein; Akl, Selim G.; Fichtinger, Gabor

    2015-03-01

    Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter. The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer. The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm. Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.

  12. Robot path planning using a genetic algorithm

    Science.gov (United States)

    Cleghorn, Timothy F.; Baffes, Paul T.; Wang, Liu

    1988-01-01

    Robot path planning can refer either to a mobile vehicle such as a Mars Rover, or to an end effector on an arm moving through a cluttered workspace. In both instances there may exist many solutions, some of which are better than others, either in terms of distance traversed, energy expended, or joint angle or reach capabilities. A path planning program has been developed based upon a genetic algorithm. This program assumes global knowledge of the terrain or workspace, and provides a family of good paths between the initial and final points. Initially, a set of valid random paths are constructed. Successive generations of valid paths are obtained using one of several possible reproduction strategies similar to those found in biological communities. A fitness function is defined to describe the goodness of the path, in this case including length, slope, and obstacle avoidance considerations. It was found that with some reproduction strategies, the average value of the fitness function improved for successive generations, and that by saving the best paths of each generation, one could quite rapidly obtain a collection of good candidate solutions.

  13. Reaction path synthesis methodology for waste minimization

    Institute of Scientific and Technical Information of China (English)

    HU; Shanying; LI; Mingheng; LI; Yourun; SHEN; Jingzhu; LIU

    2004-01-01

    It is a key step for reducing waste generation in chemical processes to design optimal reaction paths. In this paper, methods of waste minimization for reaction path synthesis problems are proposed to realize eco-industrial production mode with minimum waste emission. A new conception of simple stoichiometric reaction is presented for reaction path synthesis problem. All simple stoichiometric reactions can be obtained by mathematical transformation for atom matrix of a reaction system. Based on the conception, a two-tier optimization method for complex reaction path synthesis problems is addressed. The first step is to determine the economic optimal overall reactions, and the second step to decompose each overall reaction into several sub-reactions and find out the best thermodynamic feasible reaction path. Further, a method of reaction path synthesis with waste closed-cycle is proposed based on simple stoichiometric reactions for achieving zero waste emission to poly-generation problem of multi-products. Case studies show that the proposed methods can efficiently solve practical reaction path synthesis problems.

  14. Interpersonal Competence Mediating Paths from Social Perspective-taking and Public Self-consciousness to Adolescents' Emotional Adaption%他人定向变量影响青少年孤独感和社交焦虑:人际能力作中介

    Institute of Scientific and Technical Information of China (English)

    王明忠; 周宗奎; 范翠英; 孙晓军

    2012-01-01

    465 high school students were conveniently chosen as our subjects who were investigated with such instruments as the Interpersonal Competence Questionnaire, the Self-Consciousness Scale, UCLA Loneliness Scale and The Perspective-taking Subscale. With every class as a unit and under the supervision of two psychological graduates, these scales were administered to adolescents. Data were collected and analyzed by using SPSS 17.0 and LISREL 8.80. Results strongly supported the hypothetical model. Both social perspective-taking and public self-consciousness could directly positively predict the interpersonal competence and social anxiety of adolescents; The interpersonal competence could negatively predict their loneliness and social anxiety; The interpersonal competence could completely mediate the path from social perspective-taking to their loneliness as well as the path from public self-consciousness to their loneliness; The interpersonal competence could partially mediate the path from social perspective-taking to social anxiety as well as the path from public self-consciousness to their social anxiety. Further analysis revealed that adolescents show significantly different levels of interpersonal competence in different interpersonal contexts. And social perspective-taking, as well as public self-consciousness, contribute significantly differently to adolescents' interpersonal competence in different interpersonal contexts. We discussed the significance of this study for improving adolescents' interpersonal competence and relieving their loneliness and social anxiety by improving their social perspective taking and public self-consciousness.%利用自我意识量袁中的公众自我意识分量表和社交焦虑分量表,人际能力量表和骨少年孤独感量表调查465名高中生。探索社会观点采择、公众自我意识和同伴交往中的人际能力对青少年情绪适应的影响。结果表明:青少年社会观点采择和公众自

  15. Can Maxwell's fish eye lens really give perfect imaging?

    CERN Document Server

    Sun, Fei

    2010-01-01

    Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point images for a single object point are also demonstrated.

  16. Osteocyte regulation of bone mineral: a little give and take.

    Science.gov (United States)

    Atkins, G J; Findlay, D M

    2012-08-01

    Osteocytes actively participate in almost every phase of mineral handling by bone. They regulate the mineralisation of osteoid during bone formation, and they are also a major RANKL-producing cell. Osteocytes are thus able to liberate bone mineral by regulating osteoclast differentiation and activity in response to a range of stimuli, including bone matrix damage, bone disuse and mechanical unloading, oestrogen deficiency, high-dose glucocorticoid and chemotherapeutic agents. At least some of these activities may be regulated by the osteocyte-secreted product, sclerostin. There is also mounting evidence that in addition to regulating phosphate homeostasis systemically, osteocytes contribute directly to calcium homeostasis in the mature skeleton. Osteocyte cell death and the local loss of control of bone mineralisation may be the cause of focal hypermineralisation of bone and osteopetrosis, as seen in aging and pathology. The sheer number of osteocytes in bone means that "a little give and take" in terms of regulation of bone mineral content translates into a powerful whole organism effect.

  17. Does friendship give us non-derivative partial reasons ?

    Directory of Open Access Journals (Sweden)

    Andrew Reisner

    2008-02-01

    Full Text Available One way to approach the question of whether there are non-derivative partial reasons of any kind is to give an account of what partial reasons are, and then to consider whether there are such reasons. If there are, then it is at least possible that there are partial reasons of friendship. It is this approach that will be taken here, and it produces several interesting results. The first is a point about the structure of partial reasons. It is at least a necessary condition of a reason’s being partial that it has an explicit relational component. This component, technically, is a relatum in the reason relation that itself is a relation between the person to whom the reason applies and the person whom the action for which there is a reason concerns. The second conclusion of the paper is that this relational component is also required for a number of types of putatively impartial reasons. In order to avoid trivialising the distinction between partial and impartial reasons, some further sufficient condition must be applied. Finally, there is some prospect for a way of distinguishing between impartial reasons that contain a relational component and partial reasons, but that this approach suggests that the question of whether ethics is partial or impartial will be settled at the level of normative ethical discourse, or at least not at the level of discourse about the nature of reasons for action.

  18. Climate Change Adaptation

    DEFF Research Database (Denmark)

    Hudecz, Adriána

    -operation and research into the common problems of the Northern Periphery. This report is an output of the ROADEX “Implementing Accessibility” project (2009-2012). It gives a summary of the results of research into adaptation measures to combat climate change effects on low volume roads in the Northern Periphery....... The research was carried out between January 2000 and March 2012. One of the biggest challenges that mankind has to face is the prospect of climate change resulting from emissions of greenhouse gases. These gases trap energy in the atmosphere and cause global surface temperatures to rise. This warming in turn...... causes changes in other climatic variables such as rainfall, humidity and wind speed that impact on the functioning of infrastructure such road networks. This paper discusses the climate changes predicted by the world’s meteorological organisations and considers how these may impact on the public...

  19. Path integral representations on the complex sphere

    Energy Technology Data Exchange (ETDEWEB)

    Grosche, C. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2007-08-15

    In this paper we discuss the path integral representations for the coordinate systems on the complex sphere S{sub 3C}. The Schroedinger equation, respectively the path integral, separates in exactly 21 orthogonal coordinate systems. We enumerate these coordinate systems and we are able to present the path integral representations explicitly in the majority of the cases. In each solution the expansion into the wave-functions is stated. Also, the kernel and the corresponding Green function can be stated in closed form in terms of the invariant distance on the sphere, respectively on the hyperboloid. (orig.)

  20. INVESTMENT DEVELOPMENT PATH – CONCEPT AND TERMS

    Directory of Open Access Journals (Sweden)

    Ovidiu Serafim TRUFIN

    2015-04-01

    Full Text Available This article aims to analyze and explain the traditional model of Investment Development Path with new teoretical approaches. Investment Develoment Path is the latest theory about foreign direct investment and explains the relationship between a country’s development level and international investment position of a country. It has become a necessity in this research field of Romanian economy to establish a idiosyncratic model for evolution of inflows and outflows of Foreign Direct Investments after 1990. Also, persistent confusion between static and dynamic nature in using appropriate economic Romanian terms is removed. General theoretical approach is enhanced with new elements of schematic theorizing of Stages of Investment Development Path.

  1. Fluctuating paths and fields Festschrift Kleinert (Hagen)

    CERN Document Server

    Bachmann, M; Schmidt, H J; Janke, W

    2001-01-01

    This volume covers the following fields: path integrals, quantum field theory, variational perturbation theory, phase transitions and critical phenomena, topological defects, strings and membranes, gravitation and cosmology. Contents: Path Integrals and Quantum Mechanics: Semiclassical Quantum Mechanics: A Path-Integral Approach (B R Holstein); Conjecture on the Reality of Spectra of Non-Hermitian Hamiltonians (C M Bender et al.); Time-Transformation Approach to q -Deformed Objects (A Inomata); Characterizing Volume Forms (P Cartier et al.); Vassiliev Invariants and Functional Integration (L H

  2. Extending the application of critical path methods.

    Science.gov (United States)

    Coffey, R J; Othman, J E; Walters, J I

    1995-01-01

    Most health care organizations are using critical pathways in an attempt to reduce the variation in patient care, improve quality, enhance communication, and reduce costs. Virtually all of the critical path efforts to date have developed tables of treatments, medications, and so forth by day and have displayed them in a format known as a Gantt chart. This article presents a methodology for identifying the true "time-limiting" critical path, describes three additional methods for presenting the information--the network, precedent, and resource formats--and shows how these can significantly enhance current critical path efforts.

  3. Test Derivation Through Critical Path Transitions

    Institute of Scientific and Technical Information of China (English)

    李卫东; 魏道政

    1992-01-01

    In this paper, a new technique called test derivation is presented,aiming at the promotion of the random testing efficiency for combinational circuits,Combined with a fault simulator based on critical path tracing method,we introduce the concept of seed test derivation and attempt to generate a group of new tests from the seed test by means of critical path transition.The neccessary conditions and efficient algorithms are proposed to guarantee the usefulness of the newly derived tests and the correctness of the critical path transitions.Also,examples are given to demonstrate the effectiveness of the technique.

  4. Which fMRI clustering gives good brain parcellations?

    Directory of Open Access Journals (Sweden)

    Bertrand eThirion

    2014-07-01

    Full Text Available Analysis and interpretation of neuroimaging data often require one to divide the brain into a number of regions, or parcels, with homogeneous characteristics, be these regions defined in the brain volume or on on the cortical surface. While predefined brain atlases do not adapt to the signal in the individual subjects images, parcellation approaches use brain activity (e.g. found in some functional contrasts of interest and clustering techniques to define regions with some degree of signal homogeneity. In this work, we address the question of which clustering technique is appropriate and how to optimize the corresponding model. We use two principled criteria: goodness of fit (accuracy, and reproducibility of the parcellation across bootstrap samples. We study these criteria on both simulated and two task-based functional Magnetic Resonance Imaging datasets for the Ward, spectral and K-means clustering algorithms. We show that in general Ward’s clustering performs better than alternative methods with regards to reproducibility and accuracy and that the two criteria diverge regarding the preferred models (reproducibility leading to more conservative solutions, thus deferring the practical decision to a higher level alternative, namely the choice of a trade-off between accuracy and stability.

  5. Optimal Hops-Based Adaptive Clustering Algorithm

    Science.gov (United States)

    Xuan, Xin; Chen, Jian; Zhen, Shanshan; Kuo, Yonghong

    This paper proposes an optimal hops-based adaptive clustering algorithm (OHACA). The algorithm sets an energy selection threshold before the cluster forms so that the nodes with less energy are more likely to go to sleep immediately. In setup phase, OHACA introduces an adaptive mechanism to adjust cluster head and load balance. And the optimal distance theory is applied to discover the practical optimal routing path to minimize the total energy for transmission. Simulation results show that OHACA prolongs the life of network, improves utilizing rate and transmits more data because of energy balance.

  6. Sparse adaptive filters for echo cancellation

    CERN Document Server

    Paleologu, Constantin

    2011-01-01

    Adaptive filters with a large number of coefficients are usually involved in both network and acoustic echo cancellation. Consequently, it is important to improve the convergence rate and tracking of the conventional algorithms used for these applications. This can be achieved by exploiting the sparseness character of the echo paths. Identification of sparse impulse responses was addressed mainly in the last decade with the development of the so-called ``proportionate''-type algorithms. The goal of this book is to present the most important sparse adaptive filters developed for echo cancellati

  7. Speckle imaging through turbulent atmosphere based on adaptable pupil segmentation.

    Science.gov (United States)

    Loktev, Mikhail; Soloviev, Oleg; Savenko, Svyatoslav; Vdovin, Gleb

    2011-07-15

    We report on the first results to our knowledge obtained with adaptable multiaperture imaging through turbulence on a horizontal atmospheric path. We show that the resolution can be improved by adaptively matching the size of the subaperture to the characteristic size of the turbulence. Further improvement is achieved by the deconvolution of a number of subimages registered simultaneously through multiple subapertures. Different implementations of multiaperture geometry, including pupil multiplication, pupil image sampling, and a plenoptic telescope, are considered. Resolution improvement has been demonstrated on a ∼550 m horizontal turbulent path, using a combination of aperture sampling, speckle image processing, and, optionally, frame selection.

  8. Climatic change impacts, adaptation and associated costs in France. Intermediate report. June 2008; Impacts du changement climatique, adaptation et couts associes en France. Document d'etape. Juin 2008

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This report aims at promoting the awareness of sector-based and land challenges of climate change in terms of impacts. It gives a wide overview of the present knowledge on sector-based vulnerabilities, and allows the identification of some paths for the alleviation of these vulnerabilities. After a discussion of objectives and context, of methodological choices (data, modalities to take impacts and adaptation into account, impact assessment approach) thematic woks are reported. They are dealing with health (population vulnerability to climate change with the example of 2006 heat wave), agriculture, forest and water, energy, tourism, natural risks and insurance, territories. For each of these topics, the reports discusses vulnerability aspects, the present knowledge about the impact of climate change, and identifies the core problems as well as studies which remain to be performed

  9. Modeling DNA Dynamics by Path Integrals

    CERN Document Server

    Zoli, Marco

    2013-01-01

    Complementary strands in DNA double helix show temporary fluctuational openings which are essential to biological functions such as transcription and replication of the genetic information. Such large amplitude fluctuations, known as the breathing of DNA, are generally localized and, microscopically, are due to the breaking of the hydrogen bonds linking the base pairs (\\emph{bps}). I apply imaginary time path integral techniques to a mesoscopic Hamiltonian which accounts for the helicoidal geometry of a short circular DNA molecule. The \\emph{bps} displacements with respect to the ground state are interpreted as time dependent paths whose amplitudes are consistent with the model potential for the hydrogen bonds. The portion of the paths configuration space contributing to the partition function is determined by selecting the ensemble of paths which fulfill the second law of thermodynamics. Computations of the thermodynamics in the denaturation range show the energetic advantage for the equilibrium helicoidal g...

  10. Northern Pintail - Flight Path Telemetry [ds117

    Data.gov (United States)

    California Department of Resources — North-south flight paths of radio-tagged female northern pintails were monitored in a section of Highway 152 near Los Banos, California during 4 and 11 November and...

  11. Path dependence and independent utility regulation

    DEFF Research Database (Denmark)

    Ibsen, Christian Lyhne; Skovgaard Poulsen, Lauge

    2007-01-01

    The establishment of the Danish independent regulatory authorities for the energy and telecommunications sectors was based upon EU directives as part of their liberalisation process. Following the concepts of transaction costs and path dependency this article analyses differences in independence...

  12. Critical paths: maximizing patient care coordination.

    Science.gov (United States)

    Spath, P L

    1995-01-01

    1. With today's emphasis on horizontal and vertical integration of patient care services and the new initiatives prompted by these challenges, OR nurses are considering new methods for managing the perioperative period. One such method is the critical path. 2. A critical path defines an optimal sequencing and timing of interventions by physicians, nurses, and other staff members for a particular diagnosis or procedure, designed to better use resources, maximize quality of care, and minimize delays. 3. Hospitals implementing path-based patient care have reported cost reductions and improved team-work. Critical paths have been shown to reduce patient care costs by improving hospital efficiency, not merely by reducing physician practice variations.

  13. Path Integral Approach to Atomic Collisions

    Science.gov (United States)

    Harris, Allison

    2016-09-01

    The Path Integral technique is an alternative formulation of quantum mechanics that is based on a Lagrangian approach. In its exact form, it is completely equivalent to the Hamiltonian-based Schrödinger equation approach. Developed by Feynman in the 1940's, following inspiration from Dirac, the path integral approach has been widely used in high energy physics, quantum field theory, and statistical mechanics. However, only in limited cases has the path integral approach been applied to quantum mechanical few-body scattering. We present a theoretical and computational development of the path integral method for use in the study of atomic collisions. Preliminary results are presented for some simple systems. Ultimately, this approach will be applied to few-body ion-atom collisions. Work supported by NSF grant PHY-1505217.

  14. Path integral distance for data interpretation

    CERN Document Server

    Volchenkov, D

    2015-01-01

    The process of data interpretation is always based on the implicit introduction of equivalence relations on the set of walks over the database. Every equivalence relation on the set of walks specifies a Markov chain describing the transitions of a discrete time random walk. In order to geometrize and interpret the data, we propose the new distance between data units defined as a "Feynman path integral", in which all possible paths between any two nodes in a graph model of the data are taken into account, although some paths are more preferable than others. Such a path integral distance approach to the analysis of databases has proven its efficiency and success, especially on multivariate strongly correlated data where other methods fail to detect structural components (urban planning, historical language phylogenies, music, street fashion traits analysis, etc. ). We believe that it would become an invaluable tool for the intelligent complexity reduction and big data interpretation.

  15. Path integration in relativistic quantum mechanics

    CERN Document Server

    Redmount, I H; Redmount, Ian H.; Suen, Wai-Mo

    1993-01-01

    The simple physics of a free particle reveals important features of the path-integral formulation of relativistic quantum theories. The exact quantum-mechanical propagator is calculated here for a particle described by the simple relativistic action proportional to its proper time. This propagator is nonvanishing outside the light cone, implying that spacelike trajectories must be included in the path integral. The propagator matches the WKB approximation to the corresponding configuration-space path integral far from the light cone; outside the light cone that approximation consists of the contribution from a single spacelike geodesic. This propagator also has the unusual property that its short-time limit does not coincide with the WKB approximation, making the construction of a concrete skeletonized version of the path integral more complicated than in nonrelativistic theory.

  16. Non-classical paths in interference experiments

    CERN Document Server

    Sawant, Rahul; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-01-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well known text books in quantum mechanics implicitly and/or explicitly use this assumption which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in quantum interference experiments which provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  17. Nonclassical Paths in Quantum Interference Experiments

    Science.gov (United States)

    Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-09-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well-known text books in quantum mechanics implicitly and/or explicitly use this assumption that is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from nonclassical paths in quantum interference experiments that provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these nonclassical paths is difficult to present. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  18. Local-time representation of path integrals.

    Science.gov (United States)

    Jizba, Petr; Zatloukal, Václav

    2015-12-01

    We derive a local-time path-integral representation for a generic one-dimensional time-independent system. In particular, we show how to rephrase the matrix elements of the Bloch density matrix as a path integral over x-dependent local-time profiles. The latter quantify the time that the sample paths x(t) in the Feynman path integral spend in the vicinity of an arbitrary point x. Generalization of the local-time representation that includes arbitrary functionals of the local time is also provided. We argue that the results obtained represent a powerful alternative to the traditional Feynman-Kac formula, particularly in the high- and low-temperature regimes. To illustrate this point, we apply our local-time representation to analyze the asymptotic behavior of the Bloch density matrix at low temperatures. Further salient issues, such as connections with the Sturm-Liouville theory and the Rayleigh-Ritz variational principle, are also discussed.

  19. Noncommutative integrability, paths and quasi-determinants

    CERN Document Server

    Di Francesco, Philippe

    2010-01-01

    In previous work, we showed that the solution of certain systems of discrete integrable equations, notably $Q$ and $T$-systems, is given in terms of partition functions of positively weighted paths, thereby proving the positive Laurent phenomenon of Fomin and Zelevinsky for these cases. This method of solution is amenable to generalization to non-commutative weighted paths. Under certain circumstances, these describe solutions of discrete evolution equations in non-commutative variables: Examples are the corresponding quantum cluster algebras [BZ], the Kontsevich evolution [DFK09b] and the $T$-systems themselves [DFK09a]. In this paper, we formulate certain non-commutative integrable evolutions by considering paths with non-commutative weights, together with an evolution of the weights that reduces to cluster algebra mutations in the commutative limit. The general weights are expressed as Laurent monomials of quasi-determinants of path partition functions, allowing for a non-commutative version of the positiv...

  20. Building a path in cell biology.

    Science.gov (United States)

    Voeltz, Gia; Cheeseman, Iain

    2012-11-01

    Setting up a new lab is an exciting but challenging prospect. We discuss our experiences in finding a path to tackle some of the key current questions in cell biology and the hurdles that we have encountered along the way.

  1. A chemist building paths to cell biology.

    Science.gov (United States)

    Weibel, Douglas B

    2013-11-01

    Galileo is reported to have stated, "Measure what is measurable and make measurable what is not so." My group's trajectory in cell biology has closely followed this philosophy, although it took some searching to find this path.

  2. Atomistic modeling of different loading paths in single crystal copper and aluminum

    Directory of Open Access Journals (Sweden)

    R. Pezer

    2016-10-01

    Full Text Available Utilizing molecular dynamics (MD integration model we have investigated some of the relevant physical processes caused by different loading paths at the atomic level in Cu and Al monocrystal specimen. Interactions among the atoms in the bulk are modeled with the standard realistic Embedded Atom Method (EAM potentials. MD simulation gives us the detailed information about non-equilibrium dynamics including crystal structure defects, vacancies and dislocations. In particular, we have obtained result that indicate increase in the total energy of the crystal during loading (especially cyclic that provides us direct quantitative evidence of the metal weakening. For the basic response, we have deformed copper and aluminum single crystal according to the simple loading path and a series of multiaxial loading-paths including cyclic repetition. We compute equivalent stress-strain diagrams as well as dislocation total length vs time graphs to describe signatures of the anisotropic response of the crystal

  3. Balanced growth path solutions of a Boltzmann mean field game model for knowledge growth

    KAUST Repository

    Burger, Martin

    2016-11-18

    In this paper we study balanced growth path solutions of a Boltzmann mean field game model proposed by Lucas and Moll [15] to model knowledge growth in an economy. Agents can either increase their knowledge level by exchanging ideas in learning events or by producing goods with the knowledge they already have. The existence of balanced growth path solutions implies exponential growth of the overall production in time. We prove existence of balanced growth path solutions if the initial distribution of individuals with respect to their knowledge level satisfies a Pareto-tail condition. Furthermore we give first insights into the existence of such solutions if in addition to production and knowledge exchange the knowledge level evolves by geometric Brownian motion.

  4. i-PI: A Python interface for ab initio path integral molecular dynamics simulations

    CERN Document Server

    Ceriotti, Michele; Manolopoulos, David E

    2014-01-01

    Recent developments in path integral methodology have significantly reduced the computational expense of including quantum mechanical effects in the nuclear motion in ab initio molecular dynamics simulations. However, the implementation of these developments requires a considerable programming effort, which has hindered their adoption. Here we describe i-PI, an interface written in Python that has been designed to minimise the effort required to bring state-of-the-art path integral techniques to an electronic structure program. While it is best suited to first principles calculations and path integral molecular dynamics, i-PI can also be used to perform classical molecular dynamics simulations, and can just as easily be interfaced with an empirical forcefield code. To give just one example of the many potential applications of the interface, we use it in conjunction with the CP2K electronic structure package to showcase the importance of nuclear quantum effects in high pressure water.

  5. Impact of Beamforming on the Path Connectivity in Cognitive Radio Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Le The Dung

    2017-03-01

    Full Text Available This paper investigates the impact of using directional antennas and beamforming schemes on the connectivity of cognitive radio ad hoc networks (CRAHNs. Specifically, considering that secondary users use two kinds of directional antennas, i.e., uniform linear array (ULA and uniform circular array (UCA antennas, and two different beamforming schemes, i.e., randomized beamforming and center-directed to communicate with each other, we study the connectivity of all combination pairs of directional antennas and beamforming schemes and compare their performances to those of omnidirectional antennas. The results obtained in this paper show that, compared with omnidirectional transmission, beamforming transmission only benefits the connectivity when the density of secondary user is moderate. Moreover, the combination of UCA and randomized beamforming scheme gives the highest path connectivity in all evaluating scenarios. Finally, the number of antenna elements and degree of path loss greatly affect path connectivity in CRAHNs.

  6. A Path Algorithm for Constrained Estimation.

    Science.gov (United States)

    Zhou, Hua; Lange, Kenneth

    2013-01-01

    Many least-square problems involve affine equality and inequality constraints. Although there are a variety of methods for solving such problems, most statisticians find constrained estimation challenging. The current article proposes a new path-following algorithm for quadratic programming that replaces hard constraints by what are called exact penalties. Similar penalties arise in l1 regularization in model selection. In the regularization setting, penalties encapsulate prior knowledge, and penalized parameter estimates represent a trade-off between the observed data and the prior knowledge. Classical penalty methods of optimization, such as the quadratic penalty method, solve a sequence of unconstrained problems that put greater and greater stress on meeting the constraints. In the limit as the penalty constant tends to ∞, one recovers the constrained solution. In the exact penalty method, squared penalties!are replaced by absolute value penalties, and the solution is recovered for a finite value of the penalty constant. The exact path-following method starts at the unconstrained solution and follows the solution path as the penalty constant increases. In the process, the solution path hits, slides along, and exits from the various constraints. Path following in Lasso penalized regression, in contrast, starts with a large value of the penalty constant and works its way downward. In both settings, inspection of the entire solution path is revealing. Just as with the Lasso and generalized Lasso, it is possible to plot the effective degrees of freedom along the solution path. For a strictly convex quadratic program, the exact penalty algorithm can be framed entirely in terms of the sweep operator of regression analysis. A few well-chosen examples illustrate the mechanics and potential of path following. This article has supplementary materials available online.

  7. A novel method for robot path planning

    Institute of Scientific and Technical Information of China (English)

    CAI Qiang; LI Hai-sheng; YANG Qin; LI Ji-gang

    2009-01-01

    Path planning is one of the most important problems in the design of a mobile robot. A novel approach called generalized Voronoi diagrams (GVD) may deal with this matter. First, a method was introduced to normalize the obstacles and present efficient techniques for generating GVDs. Then a best path searching algorithm was presented. Examples implemented were given to indicate the availability of the mentioned algorithms. The approaches in this paper can also be used in applications including visualization, spatial data manipulation, etc.

  8. The Feynman Path Goes Monte Carlo

    OpenAIRE

    Sauer, Tilman

    2001-01-01

    Path integral Monte Carlo (PIMC) simulations have become an important tool for the investigation of the statistical mechanics of quantum systems. I discuss some of the history of applying the Monte Carlo method to non-relativistic quantum systems in path-integral representation. The principle feasibility of the method was well established by the early eighties, a number of algorithmic improvements have been introduced in the last two decades.

  9. Competition for shortest paths on sparse graphs.

    Science.gov (United States)

    Yeung, Chi Ho; Saad, David

    2012-05-18

    Optimal paths connecting randomly selected network nodes and fixed routers are studied analytically in the presence of a nonlinear overlap cost that penalizes congestion. Routing becomes more difficult as the number of selected nodes increases and exhibits ergodicity breaking in the case of multiple routers. The ground state of such systems reveals nonmonotonic complex behaviors in average path length and algorithmic convergence, depending on the network topology, and densities of communicating nodes and routers. A distributed linearly scalable routing algorithm is also devised.

  10. Create three distinct career paths for innovators.

    Science.gov (United States)

    O'Connor, Gina Colarelli; Corbett, Andrew; Pierantozzi, Ron

    2009-12-01

    Large companies say they Create Three Distinct want to be Career Paths for Innovators innovative, but they fundamentally mismanage their talent. Expecting innovators to grow along with their projects-from discovery to incubation to acceleration--sets them up to fail. Most people excel at one of the phases, not all three. By allowing innovation employees to develop career paths suited to their strengths, companies will create a sustainable innovation function.

  11. Feasible Path Planning for Autonomous Vehicles

    Directory of Open Access Journals (Sweden)

    Vu Trieu Minh

    2014-01-01

    Full Text Available The objective of this paper is to find feasible path planning algorithms for nonholonomic vehicles including flatness, polynomial, and symmetric polynomial trajectories subject to the real vehicle dynamical constraints. Performances of these path planning methods are simulated and compared to evaluate the more realistic and smoother generated trajectories. Results show that the symmetric polynomial algorithm provides the smoothest trajectory. Therefore, this algorithm is recommended for the development of an automatic control for autonomous vehicles.

  12. Decomposing Path : The Nanosyntax of Directional Expressions

    OpenAIRE

    Pantcheva, Marina Blagoeva

    2011-01-01

    In my thesis, I investigate directional expressions cross-linguistically. I examine the morpho-syntactic structure of expressions of Goal (to the house), Source (from the house), Route (through the house), non-transitional paths (towards the house) and, finally, delimited paths (up to the house). I conclude that all these types of directional expressions are of different syntactic complexity. Precisely, Source expressions (from) are formed on the basis of Goal expressions (to) and Route expr...

  13. Adaptive management

    DEFF Research Database (Denmark)

    Rist, Lucy; Campbell, Bruce Morgan; Frost, Peter

    2013-01-01

    in scientific articles, policy documents and management plans, but both understanding and application of the concept is mixed. This paper reviews recent literature from conservation and natural resource management journals to assess diversity in how the term is used, highlight ambiguities and consider how...... the concept might be further assessed. AM is currently being used to describe many different management contexts, scales and locations. Few authors define the term explicitly or describe how it offers a means to improve management outcomes in their specific management context. Many do not adhere to the idea......Adaptive management (AM) emerged in the literature in the mid-1970s in response both to a realization of the extent of uncertainty involved in management, and a frustration with attempts to use modelling to integrate knowledge and make predictions. The term has since become increasingly widely used...

  14. Path integral quantization corresponding to the deformed Heisenberg algebra

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Souvik, E-mail: souvick.in@gmail.com [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108 (India); Moussa, Mohamed, E-mail: mohamed.ibrahim@fsc.bu.edu.eg [Department of Physics, Faculty of Sciences, Benha University, Benha 13518 (Egypt); Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Ali, Ahmed Farag, E-mail: ahmed.ali@fsc.bu.edu.eg [Department of Physics, Faculty of Sciences, Benha University, Benha 13518 (Egypt)

    2015-11-15

    In this paper, the deformation of the Heisenberg algebra, consistent with both the generalized uncertainty principle and doubly special relativity, has been analyzed. It has been observed that, though this algebra can give rise to fractional derivative terms in the corresponding quantum mechanical Hamiltonian, a formal meaning can be given to them by using the theory of harmonic extensions of function. Depending on this argument, the expression of the propagator of the path integral corresponding to the deformed Heisenberg algebra, has been obtained. In particular, the consistent expression of the one dimensional free particle propagator has been evaluated explicitly. With this propagator in hand, it has been shown that, even in free particle case, normal generalized uncertainty principle and doubly special relativity show very much different result.

  15. Order-Optimal Consensus through Randomized Path Averaging

    CERN Document Server

    Benezit, F; Thiran, P; Vetterli, M

    2008-01-01

    Gossip algorithms have recently received significant attention, mainly because they constitute simple and robust message-passing schemes for distributed information processing over networks. However for many topologies that are realistic for wireless ad-hoc and sensor networks (like grids and random geometric graphs), the standard nearest-neighbor gossip converges as slowly as flooding ($O(n^2)$ messages). A recently proposed algorithm called geographic gossip improves gossip efficiency by a $\\sqrt{n}$ factor, by exploiting geographic information to enable multi-hop long distance communications. In this paper we prove that a variation of geographic gossip that averages along routed paths, improves efficiency by an additional $\\sqrt{n}$ factor and is order optimal ($O(n)$ messages) for grids and random geometric graphs. We develop a general technique (travel agency method) based on Markov chain mixing time inequalities, which can give bounds on the performance of randomized message-passing algorithms operating...

  16. Direct path integral estimators for isotope fractionation ratios

    CERN Document Server

    Cheng, Bingqing

    2014-01-01

    Fractionation of isotopes among distinct molecules or phases is a quantum effect which is often exploited to obtain insights on reaction mechanisms, biochemical, geochemical and atmospheric phenomena. Accurate evaluation of isotope ratios in atomistic simulations is challenging, because one needs to perform a thermodynamic integration with respect to the isotope mass, along with time-consuming path integral calculations. By re-formulating the problem as a particle exchange in the ring polymer partition function, we derive new estimators giving direct access to the differential partitioning of isotopes, which can simplify the calculations by avoiding thermodynamic integration. We demonstrate the efficiency of these estimators by applying them to investigate the isotope fractionation ratios in the gas-phase Zundel cation, and in a few simple hydrocarbons.

  17. Dynamic Shortest Path Monitoring in Spatial Networks

    Institute of Scientific and Technical Information of China (English)

    Shuo Shang; Lisi Chen; Zhe-Wei Wei; Dan-Huai Guo; Ji-Rong Wen

    2016-01-01

    With the increasing availability of real-time traffic information, dynamic spatial networks are pervasive nowa-days and path planning in dynamic spatial networks becomes an important issue. In this light, we propose and investigate a novel problem of dynamically monitoring shortest paths in spatial networks (DSPM query). When a traveler aims to a des-tination, his/her shortest path to the destination may change due to two reasons: 1) the travel costs of some edges have been updated and 2) the traveler deviates from the pre-planned path. Our target is to accelerate the shortest path computing in dynamic spatial networks, and we believe that this study may be useful in many mobile applications, such as route planning and recommendation, car navigation and tracking, and location-based services in general. This problem is challenging due to two reasons: 1) how to maintain and reuse the existing computation results to accelerate the following computations, and 2) how to prune the search space effectively. To overcome these challenges, filter-and-refinement paradigm is adopted. We maintain an expansion tree and define a pair of upper and lower bounds to prune the search space. A series of optimization techniques are developed to accelerate the shortest path computing. The performance of the developed methods is studied in extensive experiments based on real spatial data.

  18. Holographic Adaptive Optics

    Science.gov (United States)

    Andersen, G.

    For the last two decades adaptive optics has been used as a technique for correcting imaging applications and directed energy/laser targeting and laser communications systems affected by atmospheric turbulence. Typically these systems are bulky and limited to system with the potential to operate at speeds of MHz. The system utilizes a hologram to perform an all-optical wavefront analysis that removes the need for any computer. Finally, the sensing is made on a modal basis so it is largely insensitive to scintillation and obscuration. We have constructed a prototype device and will present experimental results from our research. The holographic adaptive optics system begins with the creation of a multiplexed hologram. This hologram is created by recording the maximum and minimum response functions of every actuator in the deformable mirror against a unique focused reference beam. When a wavefront of some arbitrary phase is incident on the processed hologram, a number of focal spots are created -- one pair for each actuator in the DM. The absolute phase error at each particular actuator location is simply related to the ratio of the intensity of each pair of spots. In this way we can use an array of photodetectors to give a direct readout of phase error without the need for any calculations. The advantages of holographic adaptive optics are many. To begin with, the measurement of phase error is made all optically, so the wavefront sensor directly controls the actuators in the DM without any computers. Using fast, photon counting photodetectors allows for closed loop correction limited only by the speed of the deformable mirror which in the case of MEMS devices can be 100 kHz or more. All this can be achieved in an extremely compact and lightweight package making it perfectly suited to applications such as UAV surveillance imagery and free space optical communications systems. Lastly, since the correction is made on a modal basis instead of zonal, it is virtually

  19. Service Priority based Reliable Routing Path Select Method in Smart Grid Communication Network

    Directory of Open Access Journals (Sweden)

    Kaixuan Wang

    2012-11-01

    Full Text Available The new challenges and schemes for the Smart Grid require high reliable transmission technologiesto support various types of electrical services and applications. This paper concentrates the degree of importance of services and tries to allocate more important service to more reliable network routing path to deliver the key instructions in the Smart Grid communication networks. Pareto probability distribution is used to weight the reliability of IP-based router path. In order to definition the relationship of service and reliability of router path, we devise a mapping and optimal function is presented to access. An optimal method is used for adapting to find the appropriate value to match the objective function. Finally, we validate the proposed algorithms by experiments. The simulation results show that the proposed algorithm outperforms the random routing algorithms.

  20. Application of Artificial Intelligence Methods of Tool Path Optimization in CNC Machines: A Review

    Directory of Open Access Journals (Sweden)

    Khashayar Danesh Narooei

    2014-08-01

    Full Text Available Today, in most of metal machining process, Computer Numerical Control (CNC machine tools have been very popular due to their efficiencies and repeatability to achieve high accuracy positioning. One of the factors that govern the productivity is the tool path travel during cutting a work piece. It has been proved that determination of optimal cutting parameters can enhance the machining results to reach high efficiency and minimum the machining cost. In various publication and articles, scientist and researchers adapted several Artificial Intelligence (AI methods or hybrid method for tool path optimization such as Genetic Algorithms (GA, Artificial Neural Network (ANN, Artificial Immune Systems (AIS, Ant Colony Optimization (ACO and Particle Swarm Optimization (PSO. This study presents a review of researches in tool path optimization with different types of AI methods that show the capability of using different types of optimization methods in CNC machining process.

  1. Multiple stochastic paths scheme on partially-trusted relay quantum key distribution network

    Institute of Scientific and Technical Information of China (English)

    WEN Hao; HAN ZhengFui; ZHAO YiBo; GUO GuangCan; HONG PeiLin

    2009-01-01

    Quantum key distribution (QKD) technology provides proven unconditional point-to-point security based on fundamental quantum physics. A QKD network also holds promise for secure multi-user communications over long distances at high-speed transmission rates. Although many schemes have been proposed so far, the trusted relay QKD network is still the most practical and flexible scenario. In reality, the insecurity of certain relay sections cannot be ignored, so to solve the fatal security problems of partially-trusted relay networks we suggest a multiple stochastic paths scheme. Its features are- (i) a safe probability model that may be more practical for real applications; (ii) a multi-path scheme with an upper bound for the overall safe probability; (iii) an adaptive stochastic routing algorithm to generate sufficient different paths and hidden routes. Simulation results for a typical partially-trusted relay QKD network show that this generalized scheme is effective.

  2. Construction of Time-Stamped Mobility Map for Path Tracking via Smith-Waterman Measurement Matching

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available Path tracking in wireless and mobile environments is a fundamental technology for ubiquitous location-based services (LBSs. In particular, it is very challenging to develop highly accurate and cost-efficient tracking systems applied to the anonymous areas where the floor plans are not available for security and privacy reasons. This paper proposes a novel path tracking approach for large Wi-Fi areas based on the time-stamped unlabeled mobility map which is constructed from Smith-Waterman received signal strength (RSS measurement matching. Instead of conventional location fingerprinting, we construct mobility map with the technique of dimension reduction from the raw measurement space into a low-dimensional embedded manifold. The feasibility of our proposed approach is verified by the real-world experiments in the HKUST campus Wi-Fi networks, sMobileNet. The experimental results prove that our approach is adaptive and capable of achieving an adequate precision level in path tracking.

  3. Thanatosis as an adaptive male mating strategy in the nuptial gift-giving spider Pisaura mirabilis

    DEFF Research Database (Denmark)

    Hansen, Line S.; Gonzalez, Sofía F.; Toft, Søren;

    2008-01-01

    (death feigning). Thanatosis in a sexual context is exceptional and was suggested to function as an antipredation strategy toward potentially cannibalistic females. If thanatosis serves as a protection strategy, males should death feign in response to female aggression or when they are more vulnerable...... to attack. We tested these predictions in a factorial design: males that were handicapped (1 leg removed) and hence vulnerable and control males were paired with females that were more or less aggressive intrinsically (measured toward prey). In mating trials, we recorded the tendency of males to death feign......, copulation success, and copulation duration. In addition, we investigated the effect of female mating status (virgin or mated) on these male mating components. Intrinsically aggressive females showed increased mating aggression toward males. Neither female aggressiveness, mating status, nor male...

  4. GIVE THE PUBLIC SOMETHING, SOMETHING MORE INTERESTING THAN RADIOACTIVE WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Codee, Hans D.K.

    2003-02-27

    In the Netherlands the policy to manage radioactive waste is somewhat different from that in other countries, although the practical outcome is not much different. Long-term, i.e. at least 100 years, storage in above ground engineered structures of all waste types is the first element in the Dutch policy. Second element, but equally important, is that deep geologic disposal is foreseen after the storage period. This policy was brought out in the early eighties and was communicated to the public as a practical, logical and feasible management system for the Dutch situation. Strong opposition existed at that time to deep disposal in salt domes in the Netherlands. Above ground storage at principle was not rejected because the need to do something was obvious. Volunteers for a long term storage site did not automatically emerge. A site selection procedure was followed and resulted in the present site at Vlissingen-Oost. The waste management organization, COVRA, was not really welcomed here , but was tolerated. In the nineties facilities for low and medium level waste were erected and commissioned. In the design of the facilities much attention was given to emotional factors. The first ten operational years were needed to gain trust from the local population. Impeccable conduct and behavior was necessary as well as honesty and full openness to the public Now, after some ten years, the COVRA facilities are accepted. And a new phase is entered with the commissioning of the storage facility for high level waste, the HABOG facility. A visit to that facility will not be very spectacular, activities take place only during loading and unloading. Furthermore it is a facility for waste, so unwanted material will be brought into the community. In order to give the public something more interesting the building itself is transformed into a piece of art and in the inside a special work of art will be displayed. Together with that the attitude of the company will change. We are

  5. The path to corporate responsibility.

    Science.gov (United States)

    Zadek, Simon

    2004-12-01

    Nike's tagline,"Just do it," is an inspirational call to action for the millions who wear the company's athletic gear. But in terms of corporate responsibility, Nike didn't always follow its own advice. In the 1990s, protesters railed against sweatshop conditions at some of its overseas suppliers and made Nike the global poster child for corporate ethical fecklessness. The intense pressure that activists exerted on the athletic apparel giant forced it to take a long, hard look at corporate responsibility--sooner than it might have otherwise. In this article, Simon Zadek, CEO of the UK-based institute AccountAbility, describes the bumpy route Nike has traveled to get to a better ethical place, one that cultivates and champions responsible business practices. Organizations learn in unique ways, Zadek contends, but they inevitably pass through five stages of corporate responsibility, from defensive ("It's not our fault") to compliance ("We'll do only what we have to") to managerial ("It's the business") to strategic ("It gives us a competitive edge") and, finally, to civil ("We need to make sure everybody does it"). He details Nike's arduous trek through these stages-from the company's initial defensive stance, when accusations about working conditions arose, all the way to its engagement today in the international debate about business's role in society and in public policy. As he outlines this evolution, Zadek offers valuable insights to executives grappling with the challenge of managing responsible business practices. Beyond just getting their own houses in order, the author argues, companies need to stay abreast of the public's evolving ideas about corporate roles and responsibilities. Organizations that do both will engage in what he calls"civil learning".

  6. Measurement of the transmission phase of an electron in a quantum two-path interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Takada, S., E-mail: shintaro.takada@neel.cnrs.fr; Watanabe, K. [Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); Yamamoto, M. [Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); PRESTO, JST, Kawaguchi-shi, Saitama 331-0012 (Japan); Bäuerle, C. [Université Grenoble Alpes, Institut NEEL, F-38042 Grenoble (France); CNRS, Institut NEEL, F-38042 Grenoble (France); Ludwig, A.; Wieck, A. D. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum (Germany); Tarucha, S. [Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); Center for Emergent Matter Science (CEMS), RIKEN, Wako, Saitama 351-0198 (Japan)

    2015-08-10

    A quantum two-path interferometer allows for direct measurement of the transmission phase shift of an electron, providing useful information on coherent scattering problems. In mesoscopic systems, however, the two-path interference is easily smeared by contributions from other paths, and this makes it difficult to observe the true transmission phase shift. To eliminate this problem, multi-terminal Aharonov-Bohm (AB) interferometers have been used to derive the phase shift by assuming that the relative phase shift of the electrons between the two paths is simply obtained when a smooth shift of the AB oscillations is observed. Nevertheless, the phase shifts using such a criterion have sometimes been inconsistent with theory. On the other hand, we have used an AB ring contacted to tunnel-coupled wires and acquired the phase shift consistent with theory when the two output currents through the coupled wires oscillate with well-defined anti-phase. Here, we investigate thoroughly these two criteria used to ensure a reliable phase measurement, the anti-phase relation of the two output currents, and the smooth phase shift in the AB oscillation. We confirm that the well-defined anti-phase relation ensures a correct phase measurement with a quantum two-path interference. In contrast, we find that even in a situation where the anti-phase relation is less well-defined, the smooth phase shift in the AB oscillation can still occur but does not give the correct transmission phase due to contributions from multiple paths. This indicates that the phase relation of the two output currents in our interferometer gives a good criterion for the measurement of the true transmission phase, while the smooth phase shift in the AB oscillation itself does not.

  7. Analysis of lifetime of wireless sensor network with base station moving on different paths

    Science.gov (United States)

    Singh, Ashutosh Kumar; Purohit, N.; Varma, S.

    2014-05-01

    Energy saving is the top most requirement of the wireless sensor network (WSN) for making it a cost effective technology. In this direction, minimisation of the distance between the communicating nodes should be an obvious choice, as it consumes the biggest chunk of the node energy. But the stationary nature of nodes (including the base station) in the standard WSN does not allow it; thus, the provision of a moving base station has been recently introduced. A few schemes with moving base station have already been developed but they suffer from several drawbacks, for example, the path over which the base station can move has not been considered which is highly unfeasible. An efficient and implementable moving strategy is needed to be developed, which is the primary goal of the present work. The fuzzy logic inference mechanism has been developed and the performance of the same is illustrated in terms of WSN lifetime. Lifetime of a WSN depends on many factors, for example, residual energy of nodes, distance between communicating nodes and base station, etc. Ability of fuzzy logic theory to address more than one factor simultaneously gives it an upper edge over other alternatives. The present work explores the possibilities of building either a circular shaped or a cross-shaped path in the deployment area. A relative study of the movement of base station on these paths has been presented. Simulation results show that the cross path always give better performance than circular path and the lifetime improves with increase in the length of the predefined path.

  8. High-resolution path-integral development of financial options

    CERN Document Server

    Ingber, L

    2000-01-01

    The Black-Scholes theory of option pricing has been considered for many years as an important but very approximate zeroth-order description of actual market behavior. We generalize the functional form of the diffusion of these systems and also consider multi-factor models including stochastic volatility. Daily Eurodollar futures prices and implied volatilities are fit to determine exponents of functional behavior of diffusions using methods of global optimization, Adaptive Simulated Annealing (ASA), to generate tight fits across moving time windows of Eurodollar contracts. These short-time fitted distributions are then developed into long-time distributions using a robust non-Monte Carlo path-integral algorithm, PATHINT, to generate prices and derivatives commonly used by option traders.

  9. Common-Path Interferometric Wavefront Sensing for Space Telescopes

    Science.gov (United States)

    Wallace, James Kent

    2011-01-01

    This paper presents an optical configuration for a common-path phase-shifting interferometric wavefront sensor.1 2 This sensor has a host of attractive features which make it well suited for space-based adaptive optics. First, it is strictly reflective and therefore operates broadband, second it is common mode and therefore does not suffer from systematic errors (like vibration) that are typical in other interferometers, third it is a phase-shifting interferometer and therefore benefits from both the sensitivity of interferometric sensors as well as the noise rejection afforded by synchronous detection. Unlike the Shack-Hartman wavefront sensor, it has nearly uniform sensitivity to all pupil modes. Optical configuration, theory and simulations for such a system will be discussed along with predicted performance.

  10. Disordered and Multiple Destinations Path Planning Methods for Mobile Robot in Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Yong-feng Dong

    2016-01-01

    Full Text Available In the smart home environment, aiming at the disordered and multiple destinations path planning, the sequencing rule is proposed to determine the order of destinations. Within each branching process, the initial feasible path set is generated according to the law of attractive destination. A sinusoidal adaptive genetic algorithm is adopted. It can calculate the crossover probability and mutation probability adaptively changing with environment at any time. According to the cultural-genetic algorithm, it introduces the concept of reducing turns by parallelogram and reducing length by triangle in the belief space, which can improve the quality of population. And the fallback strategy can help to jump out of the “U” trap effectively. The algorithm analyses the virtual collision in dynamic environment with obstacles. According to the different collision types, different strategies are executed to avoid obstacles. The experimental results show that cultural-genetic algorithm can overcome the problems of premature and convergence of original algorithm effectively. It can avoid getting into the local optimum. And it is more effective for mobile robot path planning. Even in complex environment with static and dynamic obstacles, it can avoid collision safely and plan an optimal path rapidly at the same time.

  11. Self-Adaptive Systems for Machine Intelligence

    CERN Document Server

    He, Haibo

    2011-01-01

    This book will advance the understanding and application of self-adaptive intelligent systems; therefore it will potentially benefit the long-term goal of replicating certain levels of brain-like intelligence in complex and networked engineering systems. It will provide new approaches for adaptive systems within uncertain environments. This will provide an opportunity to evaluate the strengths and weaknesses of the current state-of-the-art of knowledge, give rise to new research directions, and educate future professionals in this domain. Self-adaptive intelligent systems have wide application

  12. Adaptive Non-linear Control of Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Conrad, Finn

    1998-01-01

    Presentation of two new developed adaptive non-liner controllers for hydraulic actuator systems to give stable operation and improved performance.Results from the IMCIA project supported by the Danish Technical Research Council (STVF).......Presentation of two new developed adaptive non-liner controllers for hydraulic actuator systems to give stable operation and improved performance.Results from the IMCIA project supported by the Danish Technical Research Council (STVF)....

  13. Comparison of flux measurement by open-path and close-path eddy covariance systems

    Institute of Scientific and Technical Information of China (English)

    SONG; Xia; YU; Guirui; LIU; Yunfen; SUN; Xiaomin; REN; Chua

    2005-01-01

    For flux measurement, the eddy covariance technique supplies a possibility to directly measure the exchange between vegetation and atmosphere; and there are two kinds of eddy covariance systems, open-path and close-path systems. For the system error, it may result in difference of flux measurements by two systems. Therefore, it is necessary to compare the measured results from them. ChinaFLUX covers of eight sites applied the micrometeorological method, in which Changbai Mountains (CBS) and Qianyanzhou (QYZ) carried out open-path eddy covariance (OPEC) and close-path eddy covariance (CPEC) measurements synchronously.In this paper the data sets of CBS and QYZ were employed. The delay time of close-path analyzer to the open-path analyzer was calculated; the spectra and cospectra of time-series data of OPEC and CPEC were analyzed; the open-path flux measurement was used as a standard comparison, the close-path flux measurement results were evaluated. The results show that, at two sites the delay time of CO2 density for close-path analyzer was about 7.0-8.0 s, H2O density about 8.0-9.0 s; the spectrum from the open-path, close-path and 3D sonic anemometer was consistent with the expected -2/3 slope (log-log plot), and the cospectra showed the expected slope of -4/3 in the internal subrange; the CO2 flux measured by the close-path sensor was about 84% of that of open-path measurement at QYZ, about 80% at CBS, and the latent heat flux was balanced for two systems at QYZ, 86% at CBS. From the flux difference between open-path and close-path analyzers, it could be inferred that the attenuation of turbulent fluctuations in flow through tube of CPEC affected H2O flux more significantly than CO2 flux. The gap between two systems was bigger at CBS than at QYZ; the diurnal variation in CO2 flux of two measurement systems was very consistent.

  14. Unique Stellar System Gives Einstein a Thumbs-Up

    Science.gov (United States)

    2008-07-01

    Taking advantage of a unique cosmic coincidence, astronomers have measured an effect predicted by Albert Einstein's theory of General Relativity in the extremely strong gravity of a pair of superdense neutron stars. The new data indicate that the famed physicist's 93-year-old theory has passed yet another test. Double Pulsar Graphic Artist's Conception of Double Pulsar System PSR J0737-3039A/B CREDIT: Daniel Cantin, DarwinDimensions, McGill University Click on image for more graphics. The scientists used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to make a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves. "Of about 1700 known pulsars, this is the only case where two pulsars are in orbit around each other," said Rene Breton, a graduate student at McGill University in Montreal, Canada. In addition, the stars' orbital plane is aligned nearly perfectly with their line of sight to the Earth, so that one passes behind a doughnut-shaped region of ionized gas surrounding the other, eclipsing the signal from the pulsar in back. "Those eclipses are the key to making a measurement that could never be done before," Breton said. Einstein's 1915 theory predicted that, in a close system of two very massive objects, such as neutron stars, one object's gravitational tug, along with an effect of its spinning around its axis, should cause the spin axis of the other to wobble, or precess. Studies of other pulsars in binary systems had indicated that such wobbling occurred, but could not produce precise measurements of the amount of wobbling. "Measuring the amount of wobbling is what tests the details of Einstein's theory and gives a benchmark that any alternative gravitational theories must meet," said Scott Ransom of the National Radio Astronomy Observatory. The eclipses allowed the astronomers to pin

  15. Molecular internal dynamics studied by quantum path interferences in high order harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Zaïr, Amelle, E-mail: azair@imperial.ac.uk [Imperial College London, Department of Physics, Blackett Laboratory Laser Consortium, London SW7 2AZ (United Kingdom); Siegel, Thomas; Sukiasyan, Suren; Risoud, Francois; Brugnera, Leonardo; Hutchison, Christopher [Imperial College London, Department of Physics, Blackett Laboratory Laser Consortium, London SW7 2AZ (United Kingdom); Diveki, Zsolt; Auguste, Thierry [Service des Photons, Atomes et Molécules, CEA-Saclay, 91191 Gif-sur-Yvette (France); Tisch, John W.G. [Imperial College London, Department of Physics, Blackett Laboratory Laser Consortium, London SW7 2AZ (United Kingdom); Salières, Pascal [Service des Photons, Atomes et Molécules, CEA-Saclay, 91191 Gif-sur-Yvette (France); Ivanov, Misha Y.; Marangos, Jonathan P. [Imperial College London, Department of Physics, Blackett Laboratory Laser Consortium, London SW7 2AZ (United Kingdom)

    2013-03-12

    Highlights: ► Electronic trajectories in high order harmonic generation encodes attosecond and femtosecond molecular dynamical information. ► The observation of these quantum paths allows us to follow nuclear motion after ionization. ► Quantum paths interference encodes a signature of superposition of ionization channels. ► Quantum paths interference encodes a signature of transfer of population between channels due to laser coupling. ► Quantum paths interference is a promising technique to resolve ultra-fast dynamical processes after ionization. - Abstract: We investigate how short and long electron trajectory contributions to high harmonic emission and their interferences give access to information about intra-molecular dynamics. In the case of unaligned molecules, we show experimental evidence that the long trajectory contribution is more dependent upon the molecular species than the short one, providing a high sensitivity to cation nuclear dynamics from 100’s of as to a few fs after ionisation. Using theoretical approaches based on the strong field approximation and numerical integration of the time dependent Schrödinger equation, we examine how quantum path interferences encode electronic motion when the molecules are aligned. We show that the interferences are dependent upon which ionisation channels are involved and any superposition between them. In particular, quantum path interferences can encode signatures of electron dynamics if the laser field drives a coupling between the channels. Hence, molecular quantum path interferences are a promising method for attosecond spectroscopy, allowing the resolution of ultra-fast charge migration in molecules after ionisation in a self-referenced manner.

  16. Cutting-edge research in developing the library of the future new paths for building future services

    CERN Document Server

    Eden, Bradford Lee

    2015-01-01

    Cutting-Edge Research in the 21st-Century Academic Library: New Paths for Building Future Services explores examples of exciting new library services and workflows and provides opportunities for the rest of the library profession to model and adapt for their own communities and patrons.

  17. On the use of the Webb-Pearman-Leuning theory for closed-path eddy correlation measurements

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Dellwik, Ebba; Larsen, Søren Ejling

    2007-01-01

    We consider an imperfection of real closed-path eddy correlation systems-the decoupling of the water vapour and CO2 concentrations-with respect to the application of the Webb-Pearman-Leuning (WPL) theory. It is described why and how the current application of the WPL theory needs to be adapted...

  18. Accurate free energy calculation along optimized paths.

    Science.gov (United States)

    Chen, Changjun; Xiao, Yi

    2010-05-01

    The path-based methods of free energy calculation, such as thermodynamic integration and free energy perturbation, are simple in theory, but difficult in practice because in most cases smooth paths do not exist, especially for large molecules. In this article, we present a novel method to build the transition path of a peptide. We use harmonic potentials to restrain its nonhydrogen atom dihedrals in the initial state and set the equilibrium angles of the potentials as those in the final state. Through a series of steps of geometrical optimization, we can construct a smooth and short path from the initial state to the final state. This path can be used to calculate free energy difference. To validate this method, we apply it to a small 10-ALA peptide and find that the calculated free energy changes in helix-helix and helix-hairpin transitions are both self-convergent and cross-convergent. We also calculate the free energy differences between different stable states of beta-hairpin trpzip2, and the results show that this method is more efficient than the conventional molecular dynamics method in accurate free energy calculation.

  19. Parallel iterative reaction path optimization in ab initio quantum mechanical/molecular mechanical modeling of enzyme reactions.

    Science.gov (United States)

    Liu, Haiyan; Lu, Zhenyu; Cisneros, G Andres; Yang, Weitao

    2004-07-08

    The determination of reaction paths for enzyme systems remains a great challenge for current computational methods. In this paper we present an efficient method for the determination of minimum energy reaction paths with the ab initio quantum mechanical/molecular mechanical approach. Our method is based on an adaptation of the path optimization procedure by Ayala and Schlegel for small molecules in gas phase, the iterative quantum mechanical/molecular mechanical (QM/MM) optimization method developed earlier in our laboratory and the introduction of a new metric defining the distance between different structures in the configuration space. In this method we represent the reaction path by a discrete set of structures. For each structure we partition the atoms into a core set that usually includes the QM subsystem and an environment set that usually includes the MM subsystem. These two sets are optimized iteratively: the core set is optimized to approximate the reaction path while the environment set is optimized to the corresponding energy minimum. In the optimization of the core set of atoms for the reaction path, we introduce a new metric to define the distances between the points on the reaction path, which excludes the soft degrees of freedom from the environment set and includes extra weights on coordinates describing chemical changes. Because the reaction path is represented by discrete structures and the optimization for each can be performed individually with very limited coupling, our method can be executed in a natural and efficient parallelization, with each processor handling one of the structures. We demonstrate the applicability and efficiency of our method by testing it on two systems previously studied by our group, triosephosphate isomerase and 4-oxalocrotonate tautomerase. In both cases the minimum energy paths for both enzymes agree with the previously reported paths.

  20. Making Mistakes: Emotional Adaptation and Classroom Learning

    Science.gov (United States)

    McCaslin, Mary; Vriesema, Christine C.; Burggraf, Susan

    2016-01-01

    Background: We studied how students in Grades 4-6 participate in and emotionally adapt to the give-and-take of learning in classrooms, particularly when making mistakes. Our approach is consistent with researchers who (a) include cognitive appraisals in the study of emotional experiences, (b) consider how personal concerns might mediate…

  1. An Introduction to the Computerized Adaptive Testing

    Science.gov (United States)

    Tian, Jian-quan; Miao, Dan-min; Zhu, Xia; Gong, Jing-jing

    2007-01-01

    Computerized adaptive testing (CAT) has unsurpassable advantages over traditional testing. It has become the mainstream in large scale examinations in modern society. This paper gives a brief introduction to CAT including differences between traditional testing and CAT, the principles of CAT, psychometric theory and computer algorithms of CAT, the…

  2. Adaptive blood velocity estimation in medical ultrasound

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2007-01-01

    This paper investigates the use of data-adaptive spectral estimation techniques for blood velocity estimation in medical ultrasound. Current commercial systems are based on the averaged periodogram, which requires a large observation window to give sufficient spectral resolution. Herein, we propose...

  3. Default Path and Dedicated Path: A New Approach to Realize IP Directly Over WDM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Combining IP and WDM is an attractive direction for research. Instead the point to point linking method, this paper proposes a new approach to realize IP directly over WDM, called DPDP (default path and dedicated path), presents a conceivable architecture in detail and explains its working procedure. A lot of problems related with this design are also discussed.

  4. Path Analysis: A Link between Family Theory and Reseach.

    Science.gov (United States)

    Rank, Mark R.; Sabatelli, Ronald M.

    This paper discusses path analysis and the applicability of this methodology to the field of family studies. The statistical assumptions made in path analysis are presented along with a description of the two types of models within path analysis, i.e., recursive and non-recursive. Methods of calculating in the path model and the advantages of…

  5. 14 CFR 23.61 - Takeoff flight path.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff flight path. 23.61 Section 23.61... flight path. For each commuter category airplane, the takeoff flight path must be determined as follows: (a) The takeoff flight path begins 35 feet above the takeoff surface at the end of the...

  6. Giving USA 1997: The Annual Report on Philanthropy for the Year 1996.

    Science.gov (United States)

    Kaplan, Ann E., Ed.

    This report presents a comprehensive review of private philanthropy in the United States during 1996. After a preliminary section, the first section presents data on giving, using text, graphs, and charts. Sections cover: overall 1996 contributions; changes in giving by source and use; total giving (1966-1996); inflation-adjusted giving in 5-year…

  7. Quickest Paths for Different Network Router Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Rao, N.S.V.; Grimmell, W.C.; Radhakrishnan, S.; Bang, Y.C.

    2000-06-01

    The quickest path problem deals with the transmission of a message of size {sigma} from a source to a destination with the minimum end-to-end delay over a network with bandwidth and delay constraints on the links. The authors consider four basic modes and two variations for the message delivery at the nodes reflecting the mechanisms such as circuit switching, Internet protocol, and their combinations. For each of the first three modes, they present O(m{sup 2} + mn log n) time algorithm to compute the quickest path for a given message size {sigma}. For the last mode, the quickest path can be computed in O(m + n log n) time.

  8. Shortest Path Computation with No Information Leakage

    CERN Document Server

    Mouratidis, Kyriakos

    2012-01-01

    Shortest path computation is one of the most common queries in location-based services (LBSs). Although particularly useful, such queries raise serious privacy concerns. Exposing to a (potentially untrusted) LBS the client's position and her destination may reveal personal information, such as social habits, health condition, shopping preferences, lifestyle choices, etc. The only existing method for privacy-preserving shortest path computation follows the obfuscation paradigm; it prevents the LBS from inferring the source and destination of the query with a probability higher than a threshold. This implies, however, that the LBS still deduces some information (albeit not exact) about the client's location and her destination. In this paper we aim at strong privacy, where the adversary learns nothing about the shortest path query. We achieve this via established private information retrieval techniques, which we treat as black-box building blocks. Experiments on real, large-scale road networks assess the pract...

  9. Quickest Paths in Simulations of Pedestrians

    CERN Document Server

    Kretz, Tobias; Hengst, Stefan; Kautzsch, Lukas; Pohlmann, Andrej; Vortisch, Peter

    2011-01-01

    This contribution proposes a method to make agents in a microscopic simulation of pedestrian traffic walk approximately along a path of estimated minimal remaining travel time to their destination. Usually models of pedestrian dynamics are (implicitly) built on the assumption that pedestrians walk along the shortest path. Model elements formulated to make pedestrians locally avoid collisions and intrusion into personal space do not produce motion on quickest paths. Therefore a special model element is needed, if one wants to model and simulate pedestrians for whom travel time matters most (e.g. travelers in a station hall who are late for a train). Here such a model element is proposed, discussed and used within the Social Force Model.

  10. The path exchange method for hybrid LCA.

    Science.gov (United States)

    Lenzen, Manfred; Crawford, Robert

    2009-11-01

    Hybrid techniques for Life-Cycle Assessment (LCA) provide a way of combining the accuracy of process analysis and the completeness of input-output analysis. A number of methods have been suggested to implement a hybrid LCA in practice, with the main challenge being the integration of specific process data with an overarching input-output system. In this work we present a new hybrid LCA method which works at the finest input-output level of detail: structural paths. This new Path Exchange method avoids double-counting and system disturbance just as previous hybrid LCA methods, but instead of a large LCA database it requires only a minimum of external information on those structural paths that are to be represented by process data.

  11. Approximate shortest homotopic paths in weighted regions

    KAUST Repository

    Cheng, Siuwing

    2012-02-01

    A path P between two points s and t in a polygonal subdivision T with obstacles and weighted regions defines a class of paths that can be deformed to P without passing over any obstacle. We present the first algorithm that, given P and a relative error tolerance ε (0, 1), computes a path from this class with cost at most 1 + ε times the optimum. The running time is O(h 3/ε 2kn polylog (k,n,1/ε)), where k is the number of segments in P and h and n are the numbers of obstacles and vertices in T, respectively. The constant in the running time of our algorithm depends on some geometric parameters and the ratio of the maximum region weight to the minimum region weight. © 2012 World Scientific Publishing Company.

  12. Approximate Shortest Homotopic Paths in Weighted Regions

    KAUST Repository

    Cheng, Siu-Wing

    2010-01-01

    Let P be a path between two points s and t in a polygonal subdivision T with obstacles and weighted regions. Given a relative error tolerance ε ∈(0,1), we present the first algorithm to compute a path between s and t that can be deformed to P without passing over any obstacle and the path cost is within a factor 1 + ε of the optimum. The running time is O(h 3/ε2 kn polylog(k, n, 1/ε)), where k is the number of segments in P and h and n are the numbers of obstacles and vertices in T, respectively. The constant in the running time of our algorithm depends on some geometric parameters and the ratio of the maximum region weight to the minimum region weight. © 2010 Springer-Verlag.

  13. Quantum cosmology based on discrete Feynman paths

    Energy Technology Data Exchange (ETDEWEB)

    Chew, Geoffrey F.

    2002-10-10

    Although the rules for interpreting local quantum theory imply discretization of process, Lorentz covariance is usually regarded as precluding time quantization. Nevertheless a time-discretized quantum representation of redshifting spatially-homogeneous universe may be based on discrete-step Feynman paths carrying causal Lorentz-invariant action--paths that not only propagate the wave function but provide a phenomenologically-promising elementary-particle Hilbert-space basis. In a model under development, local path steps are at Planck scale while, at a much larger ''wave-function scale'', global steps separate successive wave-functions. Wave-function spacetime is but a tiny fraction of path spacetime. Electromagnetic and gravitational actions are ''at a distance'' in Wheeler-Feynman sense while strong (color) and weak (isospin) actions, as well as action of particle motion, are ''local'' in a sense paralleling the action of local field theory. ''Nonmaterial'' path segments and ''trivial events'' collaborate to define energy and gravity. Photons coupled to conserved electric charge enjoy privileged model status among elementary fermions and vector bosons. Although real path parameters provide no immediate meaning for ''measurement'', the phase of the complex wave function allows significance for ''information'' accumulated through ''gentle'' electromagnetic events involving charged matter and ''soft'' photons. Through its soft-photon content the wave function is an ''information reservoir''.

  14. EPISTEMOLOGY, TRANSLATION AND A PATH FOR MEANING

    Directory of Open Access Journals (Sweden)

    Heidy Gutierrez

    2012-06-01

    Full Text Available Abstract: Basically, this essay traces an epistemological line. It starts by mentioning how positivism has influenced thought and knowledge today, especially in the field of Translation Studies. There is also reference to the influence of continental philosophy, known as well as post-structuralism and its influence on what has been called the Cultural Turn in Translation Studies. From both paradigms, scholars work hard in order to give a scientific status to the discipline. In his path towards understanding, Paul Ricoeur has made a significant contribution with his inquiry method and his notion of meaning. Key words: Translation Studies, epistemology, meaning, event, dialectics. EPISTEMOLOGÍA, TRADUCCIÓN Y EL CAMINO HACIA EL SIGNIFICADO Resumen: Este ensayo tiene una mirada epistemológica en dos sentidos. En la primera parte del texto, se hace referencia a cómo el positivismo ha influenciado la forma en que pensamos hoy, en particular en el campo de la traductología. También se señala, de forma más breve, la influencia que el post-estructuralismo ha tenido en el cambio de paradigma en la disciplina, denominado El giro cultural en la traductología. Desde ambos paradigmas, los investigadores han intentado dar un estatus científico a la disciplina. En la segunda parte, se describe el método de investigación utilizado por el filósofo Paul Ricoeur para explicar su idea de sentido, en su recorrido hacia la comprensión. Palabras clave: Traductología, epistemología, sentido, acontecimiento, dialéctica. ÉPISTÉMOLOGIE, TRADUCTION ET LE CHEMIN VERS LE SENS Résumé : Cet essai présente une double vision épistémologique. Dans la première partie du texte, on fait référence à l'influence du positivisme sur la pensée contemporaine, en particulier, sur la pensée de la Traductologie. On fait référence aussi à l'appropriation que la Traductologie a faite de quelques idées du poststructuralisme, phénomène désigné comme Le

  15. EU-wide economic valuation of adaptation to climate change

    DEFF Research Database (Denmark)

    Jeuken, Ad; Bouwer, Laurens; Burzel, Andreas

    2016-01-01

    and benefits are explored for present and future climates, for different socio-economic developments paths and different adaptation strategies. For all models the SSP (Shared Socio-economic Pathways) 2 (‘middle of the road’), 3 (‘fragmented world’) and 5 (‘market driven development’) have been explored as well...

  16. On the influence of the Illuminati in astronomical adaptive optics

    CERN Document Server

    Morzinski, Katie M

    2012-01-01

    Astronomical adaptive optics (AO) has come into its own. Major O/IR telescopes are achieving diffraction-limited imaging; major facilities are being built with AO as an integral part. To the layperson, it may seem that AO has developed along a serpentine path. However, with a little illumination, the mark of Galileo's heirs becomes apparent in explaining the success of AO.

  17. Vessel tree extraction using locally optimal paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; van Ginneken, Bram; de Bruijne, Marleen

    2010-01-01

    This paper proposes a method to extract vessel trees by continually extending detected branches with locally optimal paths. Our approach uses a cost function from a multi scale vessel enhancement filter. Optimal paths are selected based on rules that take into account the geometric characteristics...... of the vessel tree. Experiments were performed on 10 low dose chest CT scans for which the pulmonary vessel trees were extracted. The proposed method is shown to extract a better connected vessel tree and extract more of the small peripheral vessels in comparison to applying a threshold on the output...

  18. Airway Tree Extraction with Locally Optimal Paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; Sporring, Jon; Pedersen, Jesper Johannes Holst

    2009-01-01

    This paper proposes a method to extract the airway tree from CT images by continually extending the tree with locally optimal paths. This is in contrast to commonly used region growing based approaches that only search the space of the immediate neighbors. The result is a much more robust method...... for tree extraction that can overcome local occlusions. The cost function for obtaining the optimal paths takes into account of an airway probability map as well as measures of airway shape and orientation derived from multi-scale Hessian eigen analysis on the airway probability. Significant improvements...

  19. Path planning for everday robotics with SANDROS

    Energy Technology Data Exchange (ETDEWEB)

    Watterberg, P.; Xavier, P. [Sandia National Labs., Albuquerque, NM (United States); Hwang, Y. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)

    1997-02-01

    We discuss the integration of the SANDROS path planner into a general robot simulation and control package with the inclusion of a fast geometry engine for distance calculations. This creates a single system that allows the path to be computed, simulated, and then executed on the physical robot. The architecture and usage procedures are presented. Also, we present examples of its usage in typical environments found in our organization. The resulting system is as easy to use as the general simulation system (which is in common use here) and is fast enough (example problems are solved in seconds) to be used interactively on an everyday basis.

  20. Stability Analysis of Path-vector Routing

    CERN Document Server

    Dimitri, Papadimitriou

    2012-01-01

    Most studies on path-vector routing stability have been conducted empirically by means of ad-hoc analysis of BGP data traces. None of them consider prior specification of an analytic method including the use of stability measurement metrics for the systematic analysis of BGP traces and associated meta-processing for determining the local state of the routing system. In this paper, we define a set of metrics that characterize the local stability properties of path-vector routing such as BGP (Border Gateway Protocol). By means of these stability metrics, we propose a method to analyze the effects of BGP policy- and protocol-induced instability on local routers.