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Sample records for adaptive paths give

  1. Adaptive robot path planning in changing environments

    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.

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

    Thor I. Fossen; Pettersen, Kristin Ytterstad; Galeazzi, Roberto

    2014-01-01

    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-sight (LOS) guidance principle used by ancient navigators, which is here extended to path following of Dubins paths. The unknown sideslip angle is treated as a constant parameter, which is estimated ...

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

    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.

  4. Adaptive path planning: Algorithm and analysis

    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.

  5. Robust Adaptive Photon Tracing using Photon Path Visibility

    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...

  6. Minimum-Risk Path Finding by an Adaptive Amoebal Network

    Nakagaki, Toshiyuki; Iima, Makoto; Ueda, Tetsuo; Nishiura, Yasumasa; Saigusa, Tetsu; Tero, Atsushi; Kobayashi, Ryo; Showalter, Kenneth

    2007-08-01

    When two food sources are presented to the slime mold Physarum in the dark, a thick tube for absorbing nutrients is formed that connects the food sources through the shortest route. When the light-avoiding organism is partially illuminated, however, the tube connecting the food sources follows a different route. Defining risk as the experimentally measurable rate of light-avoiding movement, the minimum-risk path is exhibited by the organism, determined by integrating along the path. A model for an adaptive-tube network is presented that is in good agreement with the experimental observations.

  7. Robot path adaptation for shared human-robot workspaces

    Zube, Angelika; Jung, A.; Frese, Christian

    2014-01-01

    In shared human-robot workspaces, safety has to be ensured by monitoring humans and other obstacles in the robot’s environment and by performing suitable robot motions to avoid collisions. In this contribution, information from multiple depth sensors is fused in an octree representing the current obstacles in consideration of occlusions. Based on this octree, the previously planned robot path is adapted using elastic bands in order to prevent collisions with humans.

  8. Adaptation in protein fitness landscapes is facilitated by indirect paths

    Wu, Nicholas C; Dai, Lei; Olson, C Anders; Lloyd-Smith, James O; Sun, Ren

    2016-01-01

    The structure of fitness landscapes is critical for understanding adaptive protein evolution. Previous empirical studies on fitness landscapes were confined to either the neighborhood around the wild type sequence, involving mostly single and double mutants, or a combinatorially complete subgraph involving only two amino acids at each site. In reality, the dimensionality of protein sequence space is higher (20L) and there may be higher-order interactions among more than two sites. Here we experimentally characterized the fitness landscape of four sites in protein GB1, containing 204 = 160,000 variants. We found that while reciprocal sign epistasis blocked many direct paths of adaptation, such evolutionary traps could be circumvented by indirect paths through genotype space involving gain and subsequent loss of mutations. These indirect paths alleviate the constraint on adaptive protein evolution, suggesting that the heretofore neglected dimensions of sequence space may change our views on how proteins evolve. DOI: http://dx.doi.org/10.7554/eLife.16965.001 PMID:27391790

  9. Horizontal Path Laser Communications Employing MEMS Adaptive Optics Correction

    Thompson, C A; Wilks, S C; Brase, J M; Young, R A; Johnson, G W; Ruggiero, A J

    2001-09-05

    Horizontal path laser communications are beginning to provide attractive alternatives for high-speed optical communications, In particular, companies are beginning to sell fiberless alternatives for intranet and sporting event video. These applications are primarily aimed at short distance applications (on the order of 1 km pathlength). There exists a potential need to extend this pathlength to distances much greater than a 1km. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method of improved signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors as well as improved communication and computational components. In this paper we detail two Adaptive Optics approaches for improved through-put, the first is the compensated receiver (the traditional Adaptive Optics approach), the second is the compensated transmitter/receiver. The second approach allows for correction of the optical wavefront before transmission from the transmitter and prior to detection at the receiver.

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

    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.

  11. UCAV Path Planning by Fitness-Scaling Adaptive Chaotic Particle Swarm Optimization

    Yudong Zhang; Lenan Wu; Shuihua Wang

    2013-01-01

    Path planning plays an extremely important role in the design of UCAVs to accomplish the air combat task fleetly and reliably. The planned path should ensure that UCAVs reach the destination along the optimal path with minimum probability of being found and minimal consumed fuel. Traditional methods tend to find local best solutions due to the large search space. In this paper, a Fitness-scaling Adaptive Chaotic Particle Swarm Optimization (FAC-PSO) approach was proposed as a fast and robust ...

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

    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...

  13. Adaptation in protein fitness landscapes is facilitated by indirect paths.

    Wu, N.; Dai, L.; Olson, CA; Lloyd-Smith, JO; Sun, R

    2016-01-01

    The structure of fitness landscapes is critical for understanding adaptive protein evolution. Previous empirical studies on fitness landscapes were confined to either the neighborhood around the wild type sequence, involving mostly single and double mutants, or a combinatorially complete subgraph involving only two amino acids at each site. In reality, the dimensionality of protein sequence space is higher (20(L)) and there may be higher-order interactions among more than two sites. Here we e...

  14. An adaptation of Krylov subspace methods to path following

    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.

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

    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.

  16. Adaptive QoS Class Allocation Schemes in Multi-Domain Path-Based Networks

    Ogino, Nagao; Nakamura, Hajime

    MPLS-based path technology shows promise as a means of realizing reliable IP networks. Real-time services such as VoIP and video-conference supplied through a multi-domain MPLS network must be able to guarantee end-to-end QoS of the inter-domain paths. Thus, it is important to allocate an appropriate QoS class to the inter-domain paths in each domain traversed by the inter-domain paths. Because each domain has its own policy for QoS class allocation, it is necessary to adaptively allocate the optimum QoS class based on estimation of the QoS class allocation policies in other domains. This paper proposes two kinds of adaptive QoS class allocation schemes, assuming that the arriving inter-domain path requests include the number of downstream domains traversed by the inter-domain paths and the remaining QoS value toward the destination nodes. First, a measurement-based scheme, based on measurement of the loss rates of inter-domain paths in the downstream domains, is proposed. This scheme estimates the QoS class allocation policies in the downstream domains, using the measured loss rates of path requests. Second, a state-dependent type scheme, based on measurement of the arrival rates of path requests in addition to the loss rates of paths in the downstream domains, is also proposed. This scheme allows an appropriate QoS class to be allocated according to the domain state. This paper proposes an application of the Markov decision theory to the modeling of state-dependent type scheme. The performances of the proposed schemes are evaluated and compared with those of the other less complicated non-adaptive schemes using a computer simulation. The results of the comparison reveal that the proposed schemes can adaptively increase the number of inter-domain paths accommodated in the considered domain, even when the QoS class allocation policies change in the other domains and the arrival pattern of path requests varies in the considered domain.

  17. Walking on an Oscillating Treadmill: Two Paths to Functional Adaptation

    Brady, Rachel A.; Peters, Brian T.; Bloomberg, Jacob J.

    2010-01-01

    We mounted a treadmill on top of a six degree-of-freedom motion base platform to investigate and characterize locomotor responses produced by healthy adults when introduced to a novel walking condition. Subjects were classified into two groups according to how their stride times were affected by the perturbation. Our data suggest that a person's choice of adaptation strategy is influenced by the relationship between his unique, natural stride frequency and the external frequency imposed by the motion base. Our data suggest that a person's stride time response while walking on a laterally oscillating treadmill is influenced by the relationship between his unique, natural stride frequency and the imposed external frequency of the motion base. This relationship may be useful for checking the efficacy of gait training and rehabilitation programs. Preselecting and manipulating a person's EST could be one way to draw him out of his preferred "entrainment well" during therapy or training.

  18. Do spatial and institutional path dependencies present barriers to climate adaptation? A case study of Copenhagen

    Driscoll, Patrick Arthur; Nicolaisen, Morten Skou

    2016-01-01

    There is a rich body of literature addressing a number of potential or actual barriers to adaptation, including informational, social, institutional, political, financial, technical, and so on. This paper posits that the spatial and temporal dimensions of barriers are missing, and proposes the...... inclusion of path dependency as a possible remedy. Through a critical case study of the process of developing and implementing three concrete plans (Copenhagen Climate Plan, Copenhagen Adaptation Plan, and Copenhagen Cloudburst Management Plan), the findings indicate that physical/spatial and institutional...... path dependencies do present challenges in the implementation of the adaptation measures. Further, empirical evidence suggests that informational, political, and financial barriers do not have a notable effect upon adaptation planning....

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

    Wulfram Gerstner

    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.

  20. Exome sequencing of geographically diverse barley landraces and wild relatives gives insights into environmental adaptation.

    Russell, Joanne; Mascher, Martin; Dawson, Ian K; Kyriakidis, Stylianos; Calixto, Cristiane; Freund, Fabian; Bayer, Micha; Milne, Iain; Marshall-Griffiths, Tony; Heinen, Shane; Hofstad, Anna; Sharma, Rajiv; Himmelbach, Axel; Knauft, Manuela; van Zonneveld, Maarten; Brown, John W S; Schmid, Karl; Kilian, Benjamin; Muehlbauer, Gary J; Stein, Nils; Waugh, Robbie

    2016-09-01

    After domestication, during a process of widespread range extension, barley adapted to a broad spectrum of agricultural environments. To explore how the barley genome responded to the environmental challenges it encountered, we sequenced the exomes of a collection of 267 georeferenced landraces and wild accessions. A combination of genome-wide analyses showed that patterns of variation have been strongly shaped by geography and that variant-by-environment associations for individual genes are prominent in our data set. We observed significant correlations of days to heading (flowering) and height with seasonal temperature and dryness variables in common garden experiments, suggesting that these traits were major drivers of environmental adaptation in the sampled germplasm. A detailed analysis of known flowering-associated genes showed that many contain extensive sequence variation and that patterns of single- and multiple-gene haplotypes exhibit strong geographical structuring. This variation appears to have substantially contributed to range-wide ecogeographical adaptation, but many factors key to regional success remain unidentified. PMID:27428750

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

    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

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

    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...

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

    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.

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

    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. PMID:26796092

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

    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.

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

    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.

  7. An Approach for Self-Adaptive Path Loss Modelling for Positioning in Underground Environments

    Evgeny Osipov

    2016-01-01

    Full Text Available This paper proposes a real-time self-adaptive approach for accurate path loss estimation in underground mines or tunnels based on signal strength measurements from heterogeneous radio communication technologies. The proposed model features simplicity of implementation. The methodology is validated in simulations and verified by measurements taken in real environments. The proposed method leverages accuracy of positioning matching the existing approaches while requiring smaller engineering efforts.

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

    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.

  9. A new online secondary path modeling method for adaptive active structure vibration control

    This paper proposes a new variable step size FXLMS algorithm with an auxiliary noise power scheduling strategy for online secondary path modeling. The step size for the secondary path modeling filter and the gain of auxiliary noise are varied in accordance with the parameters available directly. The proposed method has a low computational complexity. Computer simulations show that an active vibration control system with the proposed method gives much better vibration attenuation and modeling accuracy at a faster convergence rate than existing methods. National Instruments’ CompactRIO is used as an embedded processor to control simply supported beam vibration. Experimental results indicate that the vibration of the beam has been effectively attenuated. (papers)

  10. Adaptive Environmental Source Localization and Tracking with Unknown Permittivity and Path Loss Coefficients

    Barış Fidan

    2015-12-01

    Full Text Available Accurate signal-source and signal-reflector target localization tasks via mobile sensory units and wireless sensor networks (WSNs, including those for environmental monitoring via sensory UAVs, require precise knowledge of specific signal propagation properties of the environment, which are permittivity and path loss coefficients for the electromagnetic signal case. Thus, accurate estimation of these coefficients has significant importance for the accuracy of location estimates. In this paper, we propose a geometric cooperative technique to instantaneously estimate such coefficients, with details provided for received signal strength (RSS and time-of-flight (TOF-based range sensors. The proposed technique is integrated to a recursive least squares (RLS-based adaptive localization scheme and an adaptive motion control law, to construct adaptive target localization and adaptive target tracking algorithms, respectively, that are robust to uncertainties in aforementioned environmental signal propagation coefficients. The efficiency of the proposed adaptive localization and tracking techniques are both mathematically analysed and verified via simulation experiments.

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

    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

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

    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 ...

  13. Adaptive capacities, path creation and variants of sectoral change: The case of the transformation of the German energy supply system

    Fuchs, Gerhard; Hinderer, Nele; Kungl, Gregor; Neukirch, Mario

    2012-01-01

    "Since the proclamation of the German 'Energiewende' by the Federal Government in 2011, the transition of the energy supply system has accelerated. In 2011, the 'Helmholtz-Alliance' - 'ENERGY TRANS - Future Infrastructures for Meeting Energy Demands. Towards Sustainability and Social Compatibility" - was launched to perform an interdisciplinary analysis of the social challenges presented by the energy transition. The study presented here, 'Adaptive Capacities, Path Creation, and Variants o...

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

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

    2008-01-01

    Males and females often experience different optima in mating rate, which may cause evolution of female resistance to matings and male counter adaptations to increase mating rate. Males of the spider Pisaura mirabilis display a spectacular mating behavior involving a nuptial gift and thanatosis...... (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...

  15. Giving a chance to the 2nd path: Focal points of the 62 immediate measures and chances of their political realization

    The Commission wants especially to give preference to the measures concerning improved energy utilization and energy conservation in the following 10 years; it wants, in some way, the making up of conservation techniques to be taken for granted as opposed to the expansion of nuclear energy utilization. In addition to this rather general recommendation a majority vote was made for those famous '62 recommendations of action'. It must be assumed that the public shall be convinced that there is a further demand for nuclear power plants only if anything has been made to close the supply gaps by using energy sources like conservation and solar energy. (orig./HSCH)

  16. An Adaptive Three-Dimensional Nonlinear Path Following Method for a Fix-Wing Micro Aerial Vehicle

    Cun-Xiao Miao

    2012-11-01

    Full Text Available This paper describes an adaptive control approach of three‐dimensional (3D nonlinear path following for a fix‐wing micro aerial vehicle (MAV with wind disturbances in complicated terrain. We derive the control laws of course and flight path angle by the constructed Lyapunov function applying vector field theory based on the error equations in the Serret‐Frenet frame, which are built by virtue of the relationship between the nonlinear desired trajectory and MAV. The 3D desired trajectory is fitted by using the fifth‐order B‐splines method through a sequence of waypoints created and sent by the ground station. Furthermore, the control laws are proved to be converged asymptotically and stably based on Lyapunov stability arguments. The results of the flight test experiment show that the flight could perform well under wind disturbances with a good trajectory tracking precision and high flight quality.

  17. The optimal paths of climate change mitigation and adaptation under certainty and uncertainty

    Felgenhauer, T.; Bruin, de K.C.

    2009-01-01

    Tradeoffs between climate change mitigation and adaptation policies are explored under both certainty and uncertainty with learning using a numerical two-period decision model. We first replicate a version of the Adaptation in DICE climate model (AD-DICE) (de Bruin et al., 2009), which modifies the

  18. Scaling properties of evolutionary paths in a biophysical model of protein adaptation

    Manhart, Michael; Morozov, Alexandre V.

    2015-07-01

    The enormous size and complexity of genotypic sequence space frequently requires consideration of coarse-grained sequences in empirical models. We develop scaling relations to quantify the effect of this coarse-graining on properties of fitness landscapes and evolutionary paths. We first consider evolution on a simple Mount Fuji fitness landscape, focusing on how the length and predictability of evolutionary paths scale with the coarse-grained sequence length and alphabet. We obtain simple scaling relations for both the weak- and strong-selection limits, with a non-trivial crossover regime at intermediate selection strengths. We apply these results to evolution on a biophysical fitness landscape that describes how proteins evolve new binding interactions while maintaining their folding stability. We combine the scaling relations with numerical calculations for coarse-grained protein sequences to obtain quantitative properties of the model for realistic binding interfaces and a full amino acid alphabet.

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

    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.

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

    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

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

    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. PMID:26342354

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

    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.

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

    Goldschmidt, Dennis; Dasgupta, Sakyasingha; Wörgötter, Florentin;

    2015-01-01

    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 of......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...

  4. From Classical to Quantum and Back: A Hamiltonian Scheme for Adaptive Multiresolution Classical/Path-Integral Simulations.

    Kreis, Karsten; Tuckerman, Mark E; Donadio, Davide; Kremer, Kurt; Potestio, Raffaello

    2016-07-12

    Quantum delocalization of atomic nuclei affects the physical properties of many hydrogen-rich liquids and biological systems even at room temperature. In computer simulations, quantum nuclei can be modeled via the path-integral formulation of quantum statistical mechanics, which implies a substantial increase in computational overhead. By restricting the quantum description to a small spatial region, this cost can be significantly reduced. Herein, we derive a bottom-up, rigorous, Hamiltonian-based scheme that allows molecules to change from quantum to classical and vice versa on the fly as they diffuse through the system, both reducing overhead and making quantum grand-canonical simulations possible. The method is validated via simulations of low-temperature parahydrogen. Our adaptive resolution approach paves the way to efficient quantum simulations of biomolecules, membranes, and interfaces. PMID:27214610

  5. Adaptive Multi-Path Routing with Guaranteed Target-Delivery Ratio of Critical Events in Wireless Sensor Networks

    Baek, Jang Woon; Nam, Young Jin; Seo, Dae-Wha

    Wireless sensor networks are subject to node and link failures for a variety of reasons. This paper proposes a k-disjoint-path routing algorithm that varies the number of disjoint paths (k) in order to meet a target-delivery ratio of critical events and to reduce energy consumption. The proposed algorithm sends packets to the base station through a single path without the occurrence of critical events, however, it sends packets to the base station through k disjoint paths (k > 1) under the occurrence of critical events, where k is computed from a well-defined fault model. The proposed algorithm detects the occurrence of critical events by monitoring collected data patterns. The simulation results reveal that the proposed algorithm is more resilient to random node failure and patterned failure than other routing algorithms, and it also decreases energy consumption much more than the multi-path and path-repair algorithms.

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

    赵呈领; 陈智慧; 黄志芳

    2015-01-01

    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。%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.

  7. Physarum Can Compute Shortest Paths

    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.

  8. Adapt

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  9. Path Integral and Asset Pricing

    Zura Kakushadze

    2014-01-01

    We give a pragmatic/pedagogical discussion of using Euclidean path integral in asset pricing. We then illustrate the path integral approach on short-rate models. By understanding the change of path integral measure in the Vasicek/Hull-White model, we can apply the same techniques to "less-tractable" models such as the Black-Karasinski model. We give explicit formulas for computing the bond pricing function in such models in the analog of quantum mechanical "semiclassical" approximation. We al...

  10. Career Path Descriptions

    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...

  11. Giving an insulin injection

    ... medlineplus.gov/ency/patientinstructions/000660.htm Giving an insulin injection To use the sharing features on this ... and syringes. Filling the Syringe - One Type of Insulin Wash your hands with soap and water. Dry ...

  12. Business Gift Giving Etiquette

    Paris, Dubravka

    2015-01-01

    Business world today is faced with cultural similarities and cultural gaps. Every business person should be familiar with the business etiquette, in order to avoid a cultural faux pas. The topic of this paper is business gift giving in various parts of the world with the special emphasis on the English speaking countries. It comprises the basic rules of business gift giving etiquette, the types of gifts, especially the difference between the gifts for clients, the gifts for employees and the ...

  13. Giving Students Feedback.

    Lowman, Joseph

    1987-01-01

    Some of the special challenges associated with evaluation and grading in the large class are discussed. Suggestions for evaluation methods include seeking clarity, reducing the stress of test administration, giving feedback, guarding against errors in record keeping, and returning exams efficiently and with respect. (MLW)

  14. Give blood at CERN

    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.

  15. Asian International Students at an Australian University: Mapping the Paths between Integrative Motivation, Competence in L2 Communication, Cross-Cultural Adaptation and Persistence with Structural Equation Modelling

    Yu, Baohua

    2013-01-01

    This study examined the interrelationships of integrative motivation, competence in second language (L2) communication, sociocultural adaptation, academic adaptation and persistence of international students at an Australian university. Structural equation modelling demonstrated that the integrative motivation of international students has a…

  16. How to Safely Give Acetaminophen

    ... All About Food Allergies How to Safely Give Acetaminophen KidsHealth > For Parents > How to Safely Give Acetaminophen ... without getting a doctor's OK first. What Is Acetaminophen Also Called? Acetaminophen is the generic name of ...

  17. Are stationary hyperinflation paths learnable?

    Adam, Klaus; W., George; Honkapohja, Seppo

    2003-01-01

    Earlier studies of the seigniorage inflation model have found that the high-inflation steady state is not stable under adaptive learning. We reconsider this issue and analyze the full set of solutions for the linearized model. Our main focus is on stationary hyperinflationary paths near the high-inflation steady state. The hyperinflationary paths are stable under learning if agents can utilize contemporaneous data. However, in an economy populated by a mixture of agents, some of whom only hav...

  18. Molecular path for ligand search

    Tao Lu; Yuan Yuan Qiao; Pan Wen Shen

    2011-01-01

    A ligand is a small molecule bind to several residues of a receptor. We adapt the concept of molecular path for effective ligand search with its contacting residues. Additionally, we allow wild type definitions on atoms and bonds of molecular paths for fuzzy algorithms on structural match. We choose hydrogen bond interactions to characterize the binding mode of a ligand by several proper molecular paths and use them to query the deposited ligands in PDBe that interact with their residues in the same way. Expression of molecular path and format of database entries are described with examples. Our molecular path provides a new approach to explore the ligand-receptor interactions and to provide structural framework reference on new ligand design.

  19. An improved adaptive artificial potential field method for the path planning of multi-robot%一种改进的多机器人路径规划自适应人工势场法

    高瑜; 过金超; 崔光照

    2013-01-01

    Based on the study of the traditional multi-robot path planning,an improved adaptive artificial potential field method was proposed.In this method,the local minimum problem of the traditional artificial potential field could be solved by setting the virtual target point for mobile robot to escape local minimum. At the same time,according to the task and speed of the robot,it used the adaptive priority strategy to real-ize the adaptive obstacle avoidance of the robot.The results of the simulation proved the effectiveness and feasibility of this method.%在研究多机器人路径规划传统方法的基础上,提出了一种改进的自适应人工势场法。该方法通过设置虚拟目标点来解决传统人工势场法易陷入局部极小点的问题,同时根据各个机器人所承担的任务和速度,采用自适应优先权策略来实现机器人之间的自适应避障。仿真实验验证了该方法的有效性和可行性。

  20. Path Integration in Conical Space

    Inomata, Akira; Junker, Georg

    2011-01-01

    Quantum mechanics in conical space is studied by the path integral method. It is shown that the curvature effect gives rise to an effective potential in the radial path integral. It is further shown that the radial path integral in conical space can be reduced to a form identical with that in flat space when the discrete angular momentum of each partial wave is replaced by a specific non-integral angular momentum. The effective potential is found proportional to the squared mean curvature of ...

  1. Lexicographic Path Induction

    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 is...... routinely employed by logicians in proving such theorems, it is rarely used by programming languages researchers, who often prefer alternatives such as proofs by logical relations and model theoretic constructions. In this paper we harness the well-foundedness of the lexicographic path ordering to derive 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...

  2. Gender differences in charitable giving

    Piper, Greg; Schnepf, Sylke Viola

    2008-01-01

    The predominant part of the literature states that women are more likely to donate to charitable causes but men are more generous in terms of the amount given. The latter result generally derives from the focus on mean amount given. This paper examines gender differences in giving focusing on the distribution of amounts donated and the probability of giving using UK micro-data on individual giving to charitable causes. Results indicate that most women are more generous than men also in te...

  3. Who gives for overseas development?

    Micklewright, John; Schnepf, Sylke Viola

    2007-01-01

    Individuals' donations to overseas charities are an important source of funding for development assistance from rich industrialised countries. But little is known about the nature of these charitable donations. The literature on giving focuses on total donations to all causes and does not identify separately the pattern or the determinants of giving to any particular cause. We investigate giving to overseas causes using UK survey microdata that record individuals' donations to different types...

  4. Path Creation

    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....... 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 on an...

  5. Fitting In, without Giving In

    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?...

  6. Deconstructing Giving: Donor Types and How They Give

    Lata Gangadharan; Philip J. Grossman; Kristy Jones

    2014-01-01

    We examine the extent to which individual donors are warm glow or altruistic givers and whether this distinction motivates giving decisions, particularly paternalism. Results from our experiment suggest that motivations for giving are heterogeneous, ranging from pure altruism to impure altruism to pure warm glow. Of 115 donors, in our setting 30 are purely altruistic givers, 36 are impure givers and up to 17 could be considered pure warm-glow givers. We find that donors are predominantly pate...

  7. Give Me Your John Hancock

    王海云

    2006-01-01

    @@ When you sign your name, that's known as giving your John Hancock. John Hancock is most famous for his bold1 signature2. On August 2, 1776, he was the first member of the Continental Congress3 to sign the Declaration of Independence4, the document first demanding independence for the United States from the rule of Great Britain. Hancock wrote his name in big, bold letters that day, acting as5 president of the Second Continental Congress. This inspired6 the phrase "give me your John Hancock", meaning "give me your signature".

  8. Path integral evaluation of Dbrane amplitudes

    Chaudhuri, Shyamoli

    1999-01-01

    We extend Polchinski's evaluation of the measure for the one-loop closed string path integral to open string tree amplitudes with boundaries and crosscaps embedded in Dbranes. We explain how the nonabelian limit of near-coincident Dbranes emerges in the path integral formalism. We give a careful path integral derivation of the cylinder amplitude including the modulus dependence of the volume of the conformal Killing group.

  9. Path Minima Queries in Dynamic Weighted Trees

    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...

  10. Infinite Unicorn Paths and Gromov Boundaries

    Pho-on, Witsarut

    2015-01-01

    We extend the notion of unicorn paths between two arcs introduced by Hensel, Przytycki and Webb to the case where we replace one arc with a geodesic asymptotic to a lamination. Using these paths, we give new proofs of the results of Klarreich and Schleimer identifying the Gromov boundaries of the curve graph and the arc graph, respectively, as spaces of laminations.

  11. The Shortest Path with Intelligent Algorithm

    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.

  12. 基于网格化曲面的自适应自动铺放轨迹算法%Algorithm of Adaptive Path Planning for Automated Placement on Meshed Surface

    熊文磊; 肖军; 王显峰; 李俊斐; 黄志军

    2013-01-01

    This paper analyzes the causes of prepreg distortion and discusses its influence for the requirement of trajectory placement ability. A new algorithm of geodesic generation based on meshed surfaces is proposed according to the definition of geodesic, which possesses features of efficiency and highaccuracy, etc. Both the manufacturability of the prepreg and its distribution of strength in a product are considered in the algorithm of path planning, providing it with the ability of adapting to surfaces. The algorithm first figures out the maximum geodesic curvature allowed for the central path, and applies it to the design of trajectory. The trajectory obtained both has good ability of placement and can satisfy the demands of strength distribution in a product. Finally, the path planning aiming at one type of S-inlet with database of SQL Server and VC+ + is carried out. The disperse trajectory points are then fitted to be a curve in CATIA to verify the validity and effectiveness of the algorithm of geodesic generation and trajectory placement generation.%基于轨迹的可铺放性要求分析了铺放过程中预浸料产生畸变的原因及影响轨迹可铺放性的因素.根据测地线定义构造了一种基于网格化曲面的测地线新算法,具有高效率、高精度等特点;在此基础上综合考虑预浸料的可铺放性和构件强度分布要求,提出了具有曲面自适应功能的铺放轨迹算法,可根据预浸料带宽计算得到铺放轨迹容许的最大测地曲率,并将其运用于铺放轨迹设计,使轨迹能够保证预浸料良好可铺放性的同时又满足构件的强度分布要求.最后通过数据库SQL Server和VC++针对某型号S型进气道进行铺放轨迹设计,在CATIA中将计算获取的离散轨迹点拟合成曲线并进行了实际的铺放试验,验证了测地线生成算法和铺放轨迹生成算法的正确性和有效性.

  13. 基于白适应蚁群算法的无人飞行器航迹规划%Unmanned aerial vehicle flight path planning based on adaptive ant colony optimization algorithm

    胡中华; 赵敏; 刘世豪; 章婷

    2012-01-01

    To solve the problem of Unmanned Aerial Vehicle(UAV)route planning, Adaptive Ant Golony Optlmiza- tion(AACO)algorithm was proposed. Different from the global search mode of standard Ant Colony Optimizatio (ACO), local search mode was adopted by AACO. Based on the relative position of starting node and destination node, one of the appropriate search mode in four was selected, and transition probabilities of each candidate node were calculated. The next node was selected according to the roulette principle. The simulation result showed that AACO algorithm had advantages such as few search nodes, quick speed and so on. It could reduce flight path cost and computing time. In addition, AACO could also avoided singular flight path segment, thus the attained practical flight path could fly was guaranteed. Therefore,the performance of AACO was much better than standard ACO.%为求解无人飞行器航迹规划问题,提出自适应蚁群算法,区别于标准蚁群算法的全部搜索模式,该算法采用局部搜索模式。首先根据起始节点与目标节点的相对位置关系选择相应的搜索模式,然后计算各个待选节点的转移概率,最后按照轮盘赌规则选择下一个节点。仿真结果表明,自适应蚁群算法具有搜寻节点数少、速度快等优点,在降低了航迹代价的同时,减小了计算时间。此外,自适应蚁群算法可以避免奇异航迹段的出现,从而保证所获的航迹实际可飞,表明所提算法整体性能明显较标准蚁群算法优异。

  14. Shortest Paths between Shortest Paths and Independent Sets

    Kamiński, Marcin; Medvedev, Paul; Milanič, Martin

    We study problems of reconfiguration of shortest paths in graphs. We prove that the shortest reconfiguration sequence can be exponential in the size of the graph and that it is NP-hard to compute the shortest reconfiguration sequence even when we know that the sequence has polynomial length. Moreover, we also study reconfiguration of independent sets in three different models and analyze relationships between these models, observing that shortest path reconfiguration is a special case of independent set reconfiguration in perfect graphs, under any of the three models. Finally, we give polynomial results for restricted classes of graphs (even-hole-free and P 4-free graphs).

  15. Give Someone the Cold Shoulder

    程炜

    2002-01-01

    The snowman in this illustration is happy to allow a bird to rest on its cold shoulder.., but that's not what this idiom means.To give someone the cold shoulder is to be un-friendly, usually by ignoring them.

  16. Paths of algebraic hyperbolic curves

    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.

  17. Ranking paths in stochastic time-dependent networks

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

    2014-01-01

    some particular cases an origin–destination path must be chosen a priori, since time-adaptive choices are not allowed. Unfortunately, finding the a priori shortest path is an NP-hard problem. In this paper, we propose a solution method for the a priori shortest path problem, and we show that it can be...

  18. 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

    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

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

    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.

  20. K shortest paths in stochastic time-dependent networks

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

    2004-01-01

    A substantial amount of research has been devoted to the shortest path problem in networks where travel times are stochastic or (deterministic and) time-dependent. More recently, a growing interest has been attracted by networks that are both stochastic and time-dependent. In these networks, the...... best route choice is not necessarily a path, but rather a time-adaptive strategy that assigns successors to nodes as a function of time. In some particular cases, the shortest origin-destination path must nevertheless be chosen a priori, since time-adaptive choices are not allowed. Unfortunately......, 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...

  1. Giving a grand rounds presentation.

    Morrison, Laura J; Portenoy, Russell

    2010-12-01

    Giving a Grand Rounds presentation provides the hospice and palliative medicine subspecialist with the occasion to participate in a time-honored and respected event. It remains an opportunity to promote the discipline, support institutional culture change, and favorably influence the attitudes, knowledge, skills, and performance of colleagues. For those pursuing academic careers, it also is a chance to establish academic currency and develop teaching and presentation skills. In most academic settings, the format of Grand Rounds has shifted over time from a patient and problem-based discussion to a didactic, topic-focused lecture. A body of literature questions the value of this shift toward a more passive learner. Limited evidence prevents a definitive answer but many advocate for the integration of more interactive methods to improve the effectiveness of Grand Rounds. This article provides a flexible framework to guide those preparing to give a Grand Rounds and those teaching and supporting others to do so. To do this well, adult learning principles must be thoughtfully incorporated into a presentation style and method appropriate to the venue. The approach emphasizes learner-centeredness, interactive strategies, and evaluation. Room for creativity exists at every step and can add enjoyment and challenge along the way. PMID:21155643

  2. Analysis gives sensibility two models gives migration and transport gives radionuclides in the geosphere

    An sensibility analysis it was applied two models, the first one, a model compressible for the near field (I finish source) The second, a simple model gives migration and transport radionuclides in the geosphere. The study was developed varying the securities ed simultaneously at the same time each parameter and observing the results in changes in the output and input. The intention in analysis it is to determine the parameter that but it influences in the variation the concentration. The statistical technique Regression it was employee in the study. This statistical method is used to analyze the dependence between a dependent variable and an or but independent variables

  3. Path Separability of Graphs

    Diot, Emilie; Gavoille, Cyril

    In this paper we investigate the structural properties of k-path separable graphs, that are the graphs that can be separated by a set of k shortest paths. We identify several graph families having such path separability, and we show that this property is closed under minor taking. In particular we establish a list of forbidden minors for 1-path separable graphs.

  4. Directed Paths in a Wedge

    van Rensburg, E J J; Rechnitzer, A

    2007-01-01

    Directed paths have been used extensively in the scientific literature as a model of a linear polymer. Such paths models in particular the conformational entropy of a linear polymer and the effects it has on the free energy. These directed models are simplified versions of the self-avoiding walk, but they do nevertheless give insight into the phase behaviour of a polymer, and also serve as a tool to study the effects of conformational degrees of freedom in the behaviour of a linear polymer. In this paper we examine a directed path model of a linear polymer in a confining geometry (a wedge). The main focus of our attention is $c_n$, the number of directed lattice paths of length $n$ steps which takes steps in the North-East and South-East directions and which is confined to the wedge $Y=\\pm X/p$, where $p$ is an integer. In this paper we examine the case $p=2$ in detail, and we determine the generating function using the iterated kernel method. We also examine the asymtotics of $c_n$. In particular, we show th...

  5. The universal path integral

    Lloyd, Seth; Dreyer, Olaf

    2013-01-01

    Path integrals represent a powerful route to quantization: they calculate probabilities by summing over classical configurations of variables such as fields, assigning each configuration a phase equal to the action of that configuration. This paper defines a universal path integral, which sums over all computable structures. This path integral contains as sub-integrals all possible computable path integrals, including those of field theory, the standard model of elementary particles, discrete...

  6. Fractional path planning and path tracking

    This paper presents the main results of the application of fractional approach in path planning and path tracking. A new robust path planning design for mobile robot was studied in dynamic environment. The normalized attractive force applied to the robot is based on a fictitious fractional attractive potential. This method allows to obtain robust path planning despite robot mass variation. The danger level of each obstacles is characterized by the fractional order of the repulsive potential of the obstacles. Under these conditions, the robot dynamic behavior was studied by analyzing its X - Y path planning with dynamic target or dynamic obstacles. The case of simultaneously mobile obstacles and target is also considered. The influence of the robot mass variation is studied and the robustness analysis of the obtained path shows the robustness improvement due to the non integer order properties. Pre shaping approach is used to reduce system vibration in motion control. Desired systems inputs are altered so that the system finishes the requested move without residual vibration. This technique, developed by N.C. Singer and W.P.Seering, is used for flexible structure control, particularly in the aerospace field. In a previous work, this method was extended for explicit fractional derivative systems and applied to second generation CRONE control, the robustness was also studied. CRONE (the French acronym of Commande Robuste d'Ordre Non Entier) control system design is a frequency-domain based methodology using complex fractional integration.

  7. Paths to iDeath

    Vincent DUSSOL

    2007-06-01

    Full Text Available I am grateful to Ray DiPalma for his generously giving me access to copies of An August Daybook (2005, Mules at the Wake (2006 and Ascoso (2006. All other quotes from DiPalma are from a private correspondence.There is a delicate balance in iDEATH. It suits us.(Richard Brautigan In Watermelon SugarAn autobiography is about an “I” and it traces a path. But the “I” and teleology have long been called into question by poets. This interrogation continues: wanderers blaze new trails. We propose...

  8. Adaptable positioner

    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

  9. Adaptive positioner

    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

  10. Path Integral Methods for Stochastic Differential Equations

    Chow, Carson C.; Buice, Michael A.

    2015-01-01

    Stochastic differential equations (SDEs) have multiple applications in mathematical neuroscience and are notoriously difficult. Here, we give a self-contained pedagogical review of perturbative field theoretic and path integral methods to calculate moments of the probability density function of SDEs. The methods can be extended to high dimensional systems such as networks of coupled neurons and even deterministic systems with quenched disorder.

  11. End Simplicial Vertices in Path Graphs

    Gutierrez Marisa

    2016-05-01

    Full Text Available A graph is a path graph if there is a tree, called UV -model, whose vertices are the maximal cliques of the graph and for each vertex x of the graph the set of maximal cliques that contains it induces a path in the tree. A graph is an interval graph if there is a UV -model that is a path, called an interval model. Gimbel [3] characterized those vertices in interval graphs for which there is some interval model where the interval corresponding to those vertices is an end interval. In this work, we give a characterization of those simplicial vertices x in path graphs for which there is some UV -model where the maximal clique containing x is a leaf in this UV -model.

  12. Charitable Giving Expenditures and the Faith Factor

    Vince E. Showers; Linda S. Showers; Jeri M. Beggs; James E. Cox, Jr.

    2011-01-01

    Using a permanent income hypothesis approach and an income-giving status interaction effect, a double hurdle model provides evidence of significant differences from the impact of household income and various household characteristics on both a household's likelihood of giving and its level of giving to religion, charity, education, others outside the household, and politics. An analysis of resulting income elasticity estimates revealed that households consider religious giving a necessity goo...

  13. Income Tax Policy and Charitable Giving

    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…

  14. Charitable giving expenditures and the faith factor.

    Showers, Vince E; Showers, Linda S; Beggs, Jeri M; Cox, James E

    2011-01-01

    Using a permanent income hypothesis approach and an income-giving status interaction effect, a double hurdle model provides evidence of significant differences from the impact of household income and various household characteristics on both a household's likelihood of giving and its level of giving to religion, charity, education, others outside the household, and politics. An analysis of resulting income elasticity estimates revealed that households consider religious giving a necessity good at all levels of income, while other categories of giving are generally found to be luxury goods. Further, those who gave to religion were found to give more to education and charity then those not giving to religion, and higher education households were more likely to give to religion than households with less education. This analysis suggests that there may be more to religious giving behavior than has been assumed in prior studies and underscores the need for further research into the motivation for religious giving. Specifically, these findings point to an enduring, internal motivation for giving rather than an external, “What do I get for what I give,” motive. PMID:21322897

  15. Path Problems in Networks

    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

  16. Adaptive versus non-adaptive strategies for quantum channel discrimination

    Harrow, Aram W.; Hassidim, Avinatan; Leung, Debbie W.; Watrous, John

    2009-01-01

    We provide a simple example that illustrates the advantage of adaptive over non-adaptive strategies for quantum channel discrimination. In particular, we give a pair of entanglement-breaking channels that can be perfectly discriminated by means of an adaptive strategy that requires just two channel evaluations, but for which no non-adaptive strategy can give a perfect discrimination using any finite number of channel evaluations.

  17. Hamiltonian Paths in Two Classes of Grid Graphs

    Keshavarz-Kohjerdi, Fatemeh; Bagheri, Alireza

    2011-01-01

    In this paper, we give the necessary and sufficient conditions for the existence of Hamiltonian paths in $L-$alphabet and $C-$alphabet grid graphs. We also present a linear-time algorithm for finding Hamiltonian paths in these graphs.

  18. The maximal commutative subalgebra of a Leavitt path algebra

    Canto, Cristóbal Gil; Nasr-Isfahani, Alireza

    2015-01-01

    For any unital commutative ring $R$ and for a graph $E$, we identify a maximal commutative subalgebra of the Leavitt path algebra of $E$ with coefficients in $R$. Besides we are able to characterize injectivity of representations which gives a generalization of Cuntz-Krieger uniqueness theorem, and by other hand, to generalize and simplify the result about commutative Leavitt path algebras over fields.

  19. Mapping the imaginary of charitable giving

    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).......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...

  20. Multi-Dimensional Path Queries

    Bækgaard, Lars

    1998-01-01

    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......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 that...

  1. Identification Method of Attack Path Based on Immune Intrusion Detection

    Wenhua Huang

    2014-04-01

    Full Text Available This thesis takes researches on the immune intrusion detection and IP trace back technology. To find out the network data features of the real-time analyses, the distributed immune intrusion detection system and the packet marking theory are used; to guide the dynamically processing of path signs technology, the immune intrusion detection system is used; what’s more, to dynamically adaptive different methods of characteristics of network data, the path signs technology is adopted. After that, the attack paths can be quickly identified to provide path information for feature detector on attack path in the immune intrusion detection system. Experiment results show that this scheme can quickly reconstruct the attack path information, and the performance on the aspects of the convergence is with efficiency rate and false positive rate, which is superior to the current probabilistic packet marking algorithm and can provide characteristic path information for immune intrusion detection system

  2. Path integrals for pedestrians

    Gozzi, Ennio; Pagani, Carlo

    2016-01-01

    This book serves as a pedagogical tool to teach path integrals to students and provide work-out problems. It covers the path integral for Wigner functions and for classical mechanics. This book is also useful for researchers and professionals not familiar with the topics but are interested to learn.

  3. Path dependence and creation

    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...

  4. Phase space representations and path integrals

    Within frameworks of phase space representations in quantum mechanics and quantum field theory the Wigner distribution functions are considered, which are solutions of corresponding generalized Liouville equations. A derivation is given for representation of these distribution functions (solving of the Liouville equation) in the form of functional integrals (method is analogous to the Feynman path integral one for amplitudes). This way gives a full equality of coordinates and momenta. The expressions found are also reduced to amplitudes in the form of Feynman path integrals. A formal transition to the classical limit (h=0) is considered. Some relations of the theory of phase representations are reviewed

  5. Quantum Thermal Bath for Path Integral Molecular Dynamics Simulation.

    Brieuc, Fabien; Dammak, Hichem; Hayoun, Marc

    2016-03-01

    The quantum thermal bath (QTB) method has been recently developed to account for the quantum nature of the nuclei by using standard molecular dynamics (MD) simulation. QTB-MD is an efficient but approximate method when dealing with strongly anharmonic systems, while path integral molecular dynamics (PIMD) gives exact results but in a huge amount of computation time. The QTB and PIMD methods have been combined in order to improve the PIMD convergence or correct the failures of the QTB-MD technique. Therefore, a new power spectral density of the random force within the QTB has been developed. A modified centroid-virial estimator of the kinetic energy, especially adapted to QTB-PIMD, has also been proposed. The method is applied to selected systems: a one-dimensional double-well system, a ferroelectric phase transition, and the position distribution of an hydrogen atom in a fuel cell material. The advantage of the QTB-PIMD method is its ability to give exact results with a more reasonable computation time for strongly anharmonic systems. PMID:26799437

  6. Pulled directed lattice paths

    Van Rensburg, E J Janse, E-mail: rensburg@yorku.c [Department of Mathematics and Statistics, York University, Toronto, Ontario M3J 1P3 (Canada)

    2010-05-28

    The generating functions of models of directed walks pulled by an external force f are determined using the kernel method. These paths are models of linear polymers subject to an external force. The generating function is related to the generating function of ballot paths, and has an unexpected and non-physical singularity for the model of Dyck paths pulled at its central vertex. In each model the force-extension curve is determined exactly, and has a sigmoid shape partially given by Ctanh (cf) if f is the applied force and where c and C are the model-dependent constants. This result is consistent with previous results for models of pulled directed paths, and also with data obtained from the numerical simulation of self-avoiding walk models of linear polymers.

  7. Path Optimization Using APSO

    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.

  8. Path Optimization Using APSO

    Deepak Goyal; Malay Ranjan Tripathy

    2013-01-01

    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.

  9. Ipel educative path

    A presentation of the environmental focus of the company and its goals to the professional as well as laic public can be presented very effectively also by educative paths. On one hand, they present natural and cultural and historical features of the area but since all the objects created by human activity are located directly in this area, the paths can be used also for stressing the purpose of these objects out, on the other hand. (author)

  10. Robot Swarms in an Uncertain World: Controllable Adaptability

    Alexandr Shillerov

    2008-11-01

    Full Text Available There is a belief that complexity and chaos are essential for adaptability. But life deals with complexity every moment, without the chaos that engineers fear so, by invoking goal-directed behaviour. Goals can be programmed. That is why living organisms give us hope to achieve adaptability in robots. In this paper a method for the description of a goal-directed, or programmed, behaviour, interacting with uncertainty of environment, is described. We suggest reducing the structural (goals, intentions and stochastic components (probability to realise the goal of individual behaviour to random variables with nominal values to apply probabilistic approach. This allowed us to use a Normalized Entropy Index to detect the system state by estimating the contribution of each agent to the group behaviour. The number of possible group states is 27. We argue that adaptation has a limited number of possible paths between these 27 states. Paths and states can be programmed so that after adjustment to any particular case of task and conditions, adaptability will never involve chaos. We suggest the application of the model to operation of robots or other devices in remote and/or dangerous places.

  11. Self-calibrating common-path interferometry.

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

    2015-02-01

    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. PMID:25836191

  12. Know Concentration Before Giving Acetaminophen to Infants

    ... For Consumers Consumer Updates Know Concentration Before Giving Acetaminophen to Infants Share Tweet Linkedin Pin it More ... Consumer Updates RSS Feed Download PDF (221 K) Acetaminophen Safety (Podcast) On this page Overdosing Has Been ...

  13. Giving the 'Green Light' to Migraine Relief

    ... fullstory_158888.html Giving the 'Green Light' to Migraine Relief Experimental light therapy finds it can ease ... light -- literally -- on a potential means of easing migraine pain. Researchers in Boston exposed 69 migraine patients ...

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

    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.

  15. Lament: giving words to nurses' grief.

    Lick, Renee C

    2012-01-01

    Nurses are intimately present with people who are seriously ill, suffering and dying--giving rise to the need to cry out and give words to personal pain and grief. Practicing a regular rhythm of lament to God as found in the psalms of the Bible can assist nurses in coping with grief and prepare them to continue to care for the hurting with God's strength and hope. PMID:22866376

  16. Optimal Holder exponent for the SLE path

    Johansson, Fredrik; Lawler, Gregory F.

    2009-01-01

    We prove an upper bound on the optimal H\\"older exponent for the chordal SLE path parameterized by capacity and thereby establish the optimal exponent as conjectured by J. Lind. We also give a new proof of the lower bound. Our proofs are based on the sharp estimates of moments of the derivative of the inverse map. In particular, we improve an estimate of the second author.

  17. On path hypercompositions in graphs and automata

    Massouros Christos G.

    2016-01-01

    Full Text Available The paths in graphs define hypercompositions in the set of their vertices and therefore it is feasible to associate hypercompositional structures to each graph. Similarly, the strings of letters from their alphabet, define hypercompositions in the automata, which in turn define the associated hypergroups to the automata. The study of the associated hypercompositional structures gives results in both, graphs and automata theory.

  18. EPISTEMOLOGY, TRANSLATION AND A PATH FOR MEANING

    Heidy Gutierrez

    2012-01-01

    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 to...

  19. Shortest Paths in Microseconds

    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...

  20. Unbiased sampling of lattice Hamilton path ensembles

    Mansfield, Marc L.

    2006-10-01

    Hamilton paths, or Hamiltonian paths, are walks on a lattice which visit each site exactly once. They have been proposed as models of globular proteins and of compact polymers. A previously published algorithm [Mansfield, Macromolecules 27, 5924 (1994)] for sampling Hamilton paths on simple square and simple cubic lattices is tested for bias and for efficiency. Because the algorithm is a Metropolis Monte Carlo technique obviously satisfying detailed balance, we need only demonstrate ergodicity to ensure unbiased sampling. Two different tests for ergodicity (exact enumeration on small lattices, nonexhaustive enumeration on larger lattices) demonstrate ergodicity unequivocally for small lattices and provide strong support for ergodicity on larger lattices. Two other sampling algorithms [Ramakrishnan et al., J. Chem. Phys. 103, 7592 (1995); Lua et al., Polymer 45, 717 (2004)] are both known to produce biases on both 2×2×2 and 3×3×3 lattices, but it is shown here that the current algorithm gives unbiased sampling on these same lattices. Successive Hamilton paths are strongly correlated, so that many iterations are required between statistically independent samples. Rules for estimating the number of iterations needed to dissipate these correlations are given. However, the iteration time is so fast that the efficiency is still very good except on extremely large lattices. For example, even on lattices of total size 10×10×10 we are able to generate tens of thousands of uncorrelated Hamilton paths per hour of CPU time.

  1. Paths correlation matrix.

    Qian, Weixian; Zhou, Xiaojun; Lu, Yingcheng; Xu, Jiang

    2015-09-15

    Both the Jones and Mueller matrices encounter difficulties when physically modeling mixed materials or rough surfaces due to the complexity of light-matter interactions. To address these issues, we derived a matrix called the paths correlation matrix (PCM), which is a probabilistic mixture of Jones matrices of every light propagation path. Because PCM is related to actual light propagation paths, it is well suited for physical modeling. Experiments were performed, and the reflection PCM of a mixture of polypropylene and graphite was measured. The PCM of the mixed sample was accurately decomposed into pure polypropylene's single reflection, pure graphite's single reflection, and depolarization caused by multiple reflections, which is consistent with the theoretical derivation. Reflection parameters of rough surface can be calculated from PCM decomposition, and the results fit well with the theoretical calculations provided by the Fresnel equations. These theoretical and experimental analyses verify that PCM is an efficient way to physically model light-matter interactions. PMID:26371930

  2. Path Integration Working Memory for Multi Task Dead Reckoning and Visual Navigation

    Hasson, Cyril; Gaussier, Philippe

    2010-01-01

    International audience Biologically inspired models for navigation use mechanisms like path integration or sensori-motor learning. This paper describes the use of a proprioceptive working memory to give path integration the potential to store several goals. Then we coupled the path integration working memory to place cell sensori-motor learning to test the potential autonomy this gives to the robot. This navigation architecture intends to combine the benefits of both strategies in order to...

  3. Give and Take in Dictator Games

    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...... 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....

  4. Evolution of adaptation mechanisms: Adaptation energy, stress, and oscillating death.

    Gorban, Alexander N; Tyukina, Tatiana A; Smirnova, Elena V; Pokidysheva, Lyudmila I

    2016-09-21

    In 1938, Selye proposed the notion of adaptation energy and published 'Experimental evidence supporting the conception of adaptation energy.' Adaptation of an animal to different factors appears as the spending of one resource. Adaptation energy is a hypothetical extensive quantity spent for adaptation. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. The controversial points of view impede the systematic use of the notion of adaptation energy despite experimental evidence. Nevertheless, the response to many harmful factors often has general non-specific form and we suggest that the mechanisms of physiological adaptation admit a very general and nonspecific description. We aim to demonstrate that Selye׳s adaptation energy is the cornerstone of the top-down approach to modelling of non-specific adaptation processes. We analyze Selye׳s axioms of adaptation energy together with Goldstone׳s modifications and propose a series of models for interpretation of these axioms. Adaptation energy is considered as an internal coordinate on the 'dominant path' in the model of adaptation. The phenomena of 'oscillating death' and 'oscillating remission' are predicted on the base of the dynamical models of adaptation. Natural selection plays a key role in the evolution of mechanisms of physiological adaptation. We use the fitness optimization approach to study of the distribution of resources for neutralization of harmful factors, during adaptation to a multifactor environment, and analyze the optimal strategies for different systems of factors. PMID:26801872

  5. When does an interest path "look good"? Criteria for an appropriate future interest rate path

    Qvigstad, Jan F.

    2006-01-01

    Svensson (2004) suggested that a monetary policy committee of a central bank (MPC) should “find an instrument-rate path such that projections of inflation and output gap ‘look good’.” Academic literature on monetary policy gives guidance as to what the words “look good” means. However, there is a need for a translation of the theoretical framework into concrete criteria when an MPC shall evaluate interest rate paths in practice. Six criteria for an appropriate interest rate ...

  6. Autonomous Car Path Optimalization

    Vladyka, V.

    2015-01-01

    This paper deals with path search and optimalisation of model car in unknown space. All data from sensors are processed in real-time onboard at ARM Cortex M4 microcontroller. Model’s main sensor is line-scan camera.

  7. On the ''Feynman paths''

    The problem of time evolution of a quantum-mechanical system, which is continually observed, is rev+sited. The theorem about ''Zeno's paradox'' due to Subarshan and Misra is strengthened. Recent results of Aharonov and Vardi about ''Feynman paths'' are obtained rigorously without particular assumptions about Hamiltonian and a measuring device

  8. Path integration on manifolds

    These notes form a fairly standard introduction to Wiener integration on Rsup(n) and on Riemannian manifolds. Feynman path integrals for non-relativistic quantum mechanics are also considered and compared to Wiener integrals. The basic approach is via cylinder set measures, Gaussian measures, and abstract Wiener spaces. (Auth.)

  9. An Unplanned Path

    McGarvey, Lynn M.; Sterenberg, Gladys Y.; Long, Julie S.

    2013-01-01

    The authors elucidate what they saw as three important challenges to overcome along the path to becoming elementary school mathematics teacher leaders: marginal interest in math, low self-confidence, and teaching in isolation. To illustrate how these challenges were mitigated, they focus on the stories of two elementary school teachers--Laura and…

  10. Termination of Commercial Contracts by giving Notice

    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...

  11. Charitable Giving, Emotions, and the Default Effect

    Noussair, Charles; Habetinova, Lenka

    2015-01-01

    We report an experiment to study the effect of defaults on charitable giving. In three different treatments, participants face varying default levels of donation. In three other treatments that are paired with the first three, they receive the same defaults, but are informed that defaults are though

  12. Profiles of Effective Corporate Giving Programs.

    Knauft, E. B.

    A research study of 48 United States corporate giving programs is described. The companies are generally large or mid-range in size and represent 15 different business and industry classifications. The size of their contributions programs ranged from $98,000 to $53 million in annual grants, with a median of $4.3 million. About three-fourths of the…

  13. Homework: should we give it or not?

    Simpson, Adam John

    2014-01-01

    Homework… should we or shouldn’t we? What are the benefits and what are the drawbacks? Are we really helping our learners develop their language skills or are we merely complicating their lives? Here are my favourite four arguments for and against giving learners homework

  14. A Season of Giving. Learning with Literature.

    Freeman, Judy

    1992-01-01

    Reviews elementary school books that help steer children away from the commercial aspects of gift giving and receiving during the holiday season and focus on the gifts of caring, generosity, selflessness, friendship, and tolerance. Teaching tips, class discussions, and literary tie-ins are included. (SM)

  15. CAS paleoichthyologist gives Artedi Lecture in Sweden

    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.

  16. Giving Birth No Longer Means Death

    1999-01-01

    GIVING birth to a child was a life-or-death struggle forthe mother and baby as late as the early half of thiscentury;an estimate survey revealed a mortality rate amongmothers as high as 15 per thousand and infant mortality as highas 200 per tnousand at that time.Midwifery was oftenpracticed by the mother-in-law,the mother herself,or morepopularly,by an elderly woman in the village who practiced

  17. Giving to Africa and Perceptions of Poverty

    Alvin Etang Ndip; David Fielding; Stephen Knowles

    2010-01-01

    We conduct a simple experiment in which student participants are invited to give some of the money that they have earned to an international development charity. In different treatments, participants are given different information about the country in which the donation will be spent. The information on the country includes the countryÕs income per capita and, in some treatments, different possible reasons as to why the country is poor. We find that experimental behaviour depends largely on ...

  18. Automatic tool path generation for finish machining

    Kwok, Kwan S.; Loucks, C.S.; Driessen, B.J.

    1997-03-01

    A system for automatic tool path generation was developed at Sandia National Laboratories for finish machining operations. The system consists of a commercially available 5-axis milling machine controlled by Sandia developed software. This system was used to remove overspray on cast turbine blades. A laser-based, structured-light sensor, mounted on a tool holder, is used to collect 3D data points around the surface of the turbine blade. Using the digitized model of the blade, a tool path is generated which will drive a 0.375 inch diameter CBN grinding pin around the tip of the blade. A fuzzified digital filter was developed to properly eliminate false sensor readings caused by burrs, holes and overspray. The digital filter was found to successfully generate the correct tool path for a blade with intentionally scanned holes and defects. The fuzzified filter improved the computation efficiency by a factor of 25. For application to general parts, an adaptive scanning algorithm was developed and presented with simulation results. A right pyramid and an ellipsoid were scanned successfully with the adaptive algorithm.

  19. Graphs and Path Equilibria

    Roux, Stéphane Le

    2007-01-01

    The quest for optimal/stable paths in graphs has gained attention in a few practical or theoretical areas. To take part in this quest this chapter adopts an equilibrium-oriented approach that is abstract and general: it works with (quasi-arbitrary) arc-labelled digraphs, and it assumes very little about the structure of the sought paths and the definition of equilibrium, \\textit{i.e.} optimality/stability. In this setting, this chapter presents a sufficient condition for equilibrium existence for every graph; it also presents a necessary condition for equilibrium existence for every graph. The necessary condition does not imply the sufficient condition a priori. However, the chapter pinpoints their logical difference and thus identifies what work remains to be done. Moreover, the necessary and the sufficient conditions coincide when the definition of optimality relates to a total order, which provides a full-equivalence property. These results are applied to network routing.

  20. Spanning paths in hypercubes

    Dvořák, Tomáš; Gregor, Petr; Koubek, Václav

    2005-01-01

    Given a family \\u_i,v_i\\_i=1^k of pairwise distinct vertices of the n-dimensional hypercube Q_n such that the distance of u_i and v_i is odd and k≤n-1, there exists a family \\P_i\\_i=1^k of paths such that u_i and v_i are the endvertices of P_i and \\V(P_i)\\_i=1^k partitions V(Q_n). This holds for any n≥2 with one exception in the case when n=k+1=4. On the other hand, for any n≥3 there exist n pairs of vertices satisfying the above condition for which such a family of spanning paths does not ex...

  1. Sustainable Energy Path

    Hiromi Yamamoto; Kenji Yamaji

    2005-01-01

    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, wh...

  2. Quad-rotor flight path energy optimization

    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.

  3. Damage detection using frequency shift path

    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.

  4. Learning to improve path planning performance

    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.

  5. Learning to improve path planning performance

    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

  6. Multiple paths through a network

    Harris, Britton

    2002-01-01

    The most sophisticated iterative algorithm for balancing network congestion for a given set of desired vehicle movement from origins to destinations can generate thousands of paths of equal cost to connect a single O-D pair. Some sets of paths are combinations of minor variations on one main path, while other sets contain various degrees of difference, possibly up to complete independence. Present methods for comparing paths do not take into account the multi-dimensional nature of similaritie...

  7. Shortest Paths and Vehicle Routing

    Petersen, Bjørn; Pisinger, David

    2011-01-01

    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 Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown.

  8. Nurses' intentions to give lifestyle support.

    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. PMID:25087266

  9. Path planning in dynamic environments

    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

  10. Path Integral for Quantum Operations

    Tarasov, Vasily E.

    2007-01-01

    In this paper we consider a phase space path integral for general time-dependent quantum operations, not necessarily unitary. We obtain the path integral for a completely positive quantum operation satisfied Lindblad equation (quantum Markovian master equation). We consider the path integral for quantum operation with a simple infinitesimal generator.

  11. Glueball masses from ratios of path integrals

    Della Morte, Michele

    2011-01-01

    By generalizing our previous work on the parity symmetry, the partition function of a Yang-Mills theory is decomposed into a sum of path integrals each giving the contribution from multiplets of states with fixed quantum numbers associated to parity, charge conjugation, translations, rotations and central conjugations. Ratios of path integrals and correlation functions can then be computed with a multi-level Monte Carlo integration scheme whose numerical cost, at a fixed statistical precision and at asymptotically large times, increases power-like with the time extent of the lattice. The strategy is implemented for the SU(3) Yang-Mills theory, and a full-fledged computation of the mass and multiplicity of the lightest glueball with vacuum quantum numbers is carried out at two values of the lattice spacing (0.17 and 0.12 fm).

  12. Quantum Measurement and Extended Feynman Path Integral

    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.

  13. Electron density measurements for plasma adaptive optics

    Neiswander, Brian; Matlis, Eric; Corke, Thomas

    2014-01-01

    This study investigates the feasibility of using plasma as an adaptive optical medium for applications such as beam steering, wavefront control, and adaptive filtering. The optical path length of light propagating through plasma depends on the plasma electron density, which may be controlled via the prescribed voltage, frequency, pressure, gas, and electrode geometry. Accurate control of the optical path length requires characterization of the electron density over all operating conditions. E...

  14. Improving the Virtual Laboratories Which Give the Possibility of Evaluating the Experimental Data and Giving Feedback

    Özdener, Nesrin; Erdoğan, Barış

    2013-01-01

    The answer for “how a simulation not only giving experimental application possibility but also giving the possibility of analyzing the experimental data and being able to give feedback should be?” was searched with this study. The evaluation results by students’ observations from Newton’s II.Motion Law which is known as the main law of dynamic was aimed with the simulation developed in the study. Delphi and Flash 5 as the tool of development, Photoshop as the tool of visual design were used i...

  15. Symmetry Adapted Basis Sets

    Avery, John Scales; Rettrup, Sten; Avery, James Emil

    In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding...... such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets...

  16. Two Generations of Path Dependence

    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 or e...... economic processes have multiple possible paths of outcomes, rather than a unique path of equilibria. The selection among outcomes may depend on contingent choices or events - outcomes of path-dependent processes require a very relevant study - a perception of history....

  17. Rocket Flight Path

    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.

  18. JAVA PathFinder

    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.

  19. Thermoalgebras and path integral

    Khanna, F. C.; Malbouisson, A. P. C.; Malbouisson, J. M. C.; Santana, A. E.

    2009-09-01

    Using a representation for Lie groups closely associated with thermal problems, we derive the algebraic rules of the real-time formalism for thermal quantum field theories, the so-called thermo-field dynamics (TFD), including the tilde conjugation rules for interacting fields. These thermo-group representations provide a unified view of different approaches for finite-temperature quantum fields in terms of a symmetry group. On these grounds, a path integral formalism is constructed, using Bogoliubov transformations, for bosons, fermions and non-abelian gauge fields. The generalization of the results for quantum fields in (S1)d×R topology is addressed.

  20. Portage and Path Dependence*

    Bleakley, Hoyt; Lin, Jeffrey

    2012-01-01

    We examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the fall line, a geomorphological feature in the southeastern U.S. marking the final rapids on rivers before the ocean. Historically, waterborne transport of goods required portage around the falls at these points, while some falls provided water power during early industrialization. These factors attracted commerce and manufacturing. Although these original advantages have long since been made obsolete, we document the continuing importance of these portage sites over time. We interpret these results as path dependence and contrast explanations based on sunk costs interacting with decreasing versus increasing returns to scale. PMID:23935217

  1. Rocket Flight Path

    Jamie Waters

    2014-01-01

    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 Fl...

  2. Giving Devices the Ability to Exercise Reason

    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.

  3. Giving to Family versus Giving to the Community Within and Across Generations

    Partha Deb; Cagla Okten; Una Okonkwo Osili

    2002-01-01

    In this paper, we examine relationship between giving to family, and community institutions, within and across generations, a previously unexplored subject. We investigate the relationship between these two types of transfer networks using new data from the Indonesian Family Life Surveys (IFLS). From our results, financial transfers to family members are positively correlated with giving to community organizations for both parent or origin households and adult split-offs living outside their ...

  4. International cooperation on climate change adaptation from an economic perspective

    Bruin, de, W.; Dellink, R.B.; Tol, R.S.J.

    2010-01-01

    This paper investigates the economic incentives of countries to cooperate on international adaptation financing. Adaptation is generally implicitly incorporated in the climate change damage functions as used in Integrated Assessment Models. We replace the implicit decision on adaptation with explicit adaptation in a multi-regional setting by using an adjusted RICE model. We show that making adaptation explicit will not affect the optimal mitigation path when adaptation is set at its optimal l...

  5. Noncommutative Quantum Mechanics with Path Integral

    Dragovich, B; Dragovich, Branko; Rakic, Zoran

    2005-01-01

    We consider classical and quantum mechanics related to an additional noncommutativity, symmetric in position and momentum coordinates. We show that such mechanical system can be transformed to the corresponding one which allows employment of the usual formalism. In particular, we found explicit connections between quadratic Hamiltonians and Lagrangians, in their commutative and noncommutative regimes. In the quantum case we give general procedure how to compute Feynman's path integral in this noncommutative phase space with quadratic Lagrangians (Hamiltonians). This approach is applied to a charged particle in the noncommutative plane exposed to constant homogeneous electric and magnetic fields.

  6. The Path Research of Commercial Bank Executive Compensation Reform to Adapt to the New Normal Characteristics%商业银行高管薪酬改革适应新常态特征的路径研究

    陆岷峰; 史丽霞

    2014-01-01

    LOpment Law,fOLLOw the principLe Of the Law Of vaLue. This paper aLsO gives the basic strategies Of cOmmerciaL bank executive pay refOrm under the new nOrmaL back-grOund,such as prOmOte the restrictive Ownership system,stOck OptiOn system and the perfOrmance recycLing system, increase the deferred payments,buiLd sOciaL parity guidance and active prOfessiOnaL manager market,and imprOve the gOvernance structure Of cOmmerciaL banks.

  7. Path integral in holomorphic representation without gauge fixation

    The way of path integral (PI) construction without a gauge fixation in holomorphic representation is proposed for finite-dimensional models with a gauge group. This PI gives a manifest gauge-invariant form for the evolution operator kernel. 10 refs

  8. A discrete history of the Lorentzian path integral

    Loll, R.

    2006-01-01

    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 solv

  9. An Improved Robot Path Planning Algorithm Based on Genetic Algorithm

    Hammin Liu

    2012-12-01

    Full Text Available Robot path planning is a NP problem; traditional optimization methods are not very effective to solve it. Traditional genetic algorithm trapped into the local minimum easily. Therefore, based on a simple genetic algorithm and combine the base ideology of orthogonal design method then applied it to the population initialization, using the intergenerational elite mechanism, as well as the introduction of adaptive local search operator to prevent trapped into the local minimum and improve the convergence speed to form a new genetic algorithm. Through the series of numerical experiments, the new algorithm has been proved to be efficiency. We also use the proposed algorithm to solve the robot path planning problem and the experiment results indicated that the new algorithm is efficiency for solving the robot path planning problems and the best path usually can be found.

  10. Evolution-based path planning and management for autonomous vehicles

    Capozzi, Brian Joseph

    2001-07-01

    This dissertation describes an approach to adaptive path planning based on the problem solving capabilities witnessed in nature---namely the influence of natural selection in uncovering solutions to the characteristics of the environment. The competition for survival forces organisms to either respond to changes or risk being evolved out of the population. We demonstrate the applicability of this process to the problem of finding paths for an autonomous vehicle through a number of different static and dynamic environments. In doing so, we develop a number of different ways in which these paths can be modeled for the purposes of evolution. Through analysis and experimentation, we develop and reinforce a set of principles and conditions which must hold for the search process to be successful. Having demonstrated the viability of evolution as a guide for path planning, we discuss implications for on-line, real-time planning for autonomous vehicles.

  11. AUV Local Path Planning Based on Acoustic Image Processing

    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.

  12. innovation path exploration

    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.

  13. Adaptive Clustering of Hypermedia Documents.

    Johnson, Andrew; Fotouhi, Farshad

    1996-01-01

    Discussion of hypermedia systems focuses on a comparison of two types of adaptive algorithm (genetic algorithm and neural network) in clustering hypermedia documents. These clusters allow the user to index into the nodes to find needed information more quickly, since clustering is "personalized" based on the user's paths rather than representing…

  14. Cogema gives its communication a new impetus

    Starting 2 November 1999, COGEMA launched a mass public communication campaign and creating an Internet site, equipped with cameras (web-cams), to make everyone familiar with the COGEMA plant at La Hague. This system is designed to serve a communication policy that is resolutely open and attentive to French public concerns: - The COGEMA plant at La Hague is often perceived as a mystery, occult and dehumanized world. This communication campaign, entitled 'We have nothing to hide', illustrated COGEMA's determination to inform the citizens in the greatest possible transparence and its wish to bring the Group's industrial operations and the persons working there closer to the public. The campaign included TV commercials and press ads. The underlying principle is to work on issues that have made news. The televised system included two films, shot at La Hague. The first, lasting 90 seconds, consists of interviews and testimonies of employees who represent the professional and human diversity of the plant. The second, in 45-second format, presents the questions to which public opinion wants answers. These questions are also repeated in the press ads. - To ensure that everyone obtains all the answers to his questions, the TV spots and press ads refer to the website http://www.cogemalahague.fr and to a toll-free number 0800-64-64-64. This campaign was the first stage of a long-term approach. Its positive reception from the public strengthens COGEMA's resolution to anticipate the legitimate information's needs expressed by the public opinion. As a responsible firm, COGEMA means to adapt her communication policy in order to make the whole activities of the Group widely known. Beyond communication, COGEMA intends to carry on showing her attachment to nuclear industry and bolstering this sector's interests on the international scene. (authors)

  15. Cognitive patterns: giving autonomy some context

    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).

  16. Risk Sensitive Path Integral Control

    Broek, L.J. van den; Wiegerinck, W.A.J.J.; Kappen, H. J.

    2012-01-01

    Recently path integral methods have been developed for stochastic optimal control for a wide class of models with non-linear dynamics in continuous space-time. Path integral methods find the control that minimizes the expected cost-to-go. In this paper we show that under the same assumptions, path integral methods generalize directly to risk sensitive stochastic optimal control. Here the method minimizes in expectation an exponentially weighted cost-to-go. Depending on the exponential weight,...

  17. Path integrals on finite sets

    Thomas, EGF

    1996-01-01

    We construct an analogue of the Feynman path integral for the case of -1/i partial derivative/partial derivative t phi t = H-o phi t in which H-o is a self-adjoint operator in the space L(2)(M) = C-M, where M is a finite set, the paths being functions of R with values in M. The path integral is a fa

  18. Path Integral and Asian Options

    Peng Zhang

    2010-01-01

    In this paper we analytically study the problem of pricing an arithmetically averaged Asian option in the path integral formalism. By a trick about the Dirac delta function, the measure of the path integral is defined by an effective action functional whose potential term is an exponential function. This path integral is evaluated by use of the Feynman-Kac theorem. After working out some auxiliary integrations involving Bessel and Whittaker functions, we arrive at the spectral expansion for t...

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

    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…

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

    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.

  1. Path Integral Quantization of the Symplectic Leaves of the SU(2)* Poisson-Lie Group

    Morariu, Bogdan

    1997-01-01

    The Feynman path integral is used to quantize the symplectic leaves of the Poisson-Lie group SU(2)*. In this way we obtain the unitary representations of U_q(su(2)). This is achieved by finding explicit Darboux coordinates and then using a phase space path integral. I discuss the *-structure of SU(2)* and give a detailed description of its leaves using various parametrizations and also compare the results with the path integral quantization of spin.

  2. Adaptive Lighting

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

    2015-01-01

    Adaptive LightingAdaptive 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 i...

  3. Path Constitution Analysis: A Methodology for Understanding Path Dependence and Path Creation

    Jörg Sydow

    2012-11-01

    Full Text Available Although an increasing number of studies of technological, institutional and organizational change refer to the concepts of path dependence and path creation, few attempts have been made to consider these concepts explicitly in their methodological accounts. This paper addresses this gap and contributes to the literature by developing a comprehensive methodology that originates from the concepts of path dependence and path creation – path constitution analysis (PCA – and allows for the integration of multi-actor constellations on multiple levels of analysis within a process perspective. Based upon a longitudinal case study in the field of semiconductors, we illustrate PCA ‘in action’ as a template for other researchers and critically examine its adequacy. We conclude with implications for further path-oriented inquiries.

  4. Spin Path Integral And Quantum Mechanics In Rotating Reference of Frame

    Chern, Tong; Ning, Wu; Yue, YU

    2011-01-01

    We developed a path integral formalism for the quantum mechanics in a rotating reference of frame, and proposed a spin path integral description for the spin degrees of freedom in it. We have also give some examples for the applications of our foramlism.

  5. Path Integrals and Anomalies in Curved Space

    Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will gain from the book a

  6. Adaptive trial designs.

    Lai, Tze Leung; Lavori, Philip William; Shih, Mei-Chiung

    2012-01-01

    We review adaptive designs for clinical trials, giving special attention to the control of the Type I error in late-phase confirmatory trials, when the trial planner wishes to adjust the final sample size of the study in response to an unblinded analysis of interim estimates of treatment effects. We point out that there is considerable inefficiency in using the adaptive designs that employ conditional power calculations to reestimate the sample size and that maintain the Type I error by using certain weighted test statistics. Although these adaptive designs have little advantage over familiar group-sequential designs, our review also describes recent developments in adaptive designs that are both flexible and efficient. We also discuss the use of Bayesian designs, when the context of use demands control over operating characteristics (Type I and II errors) and correction of the bias of estimated treatment effects. PMID:21838549

  7. Application of Pre-evolution Genetic Algorithm in Fast Path Planning for UCAV

    Lu Cao

    2013-11-01

    Full Text Available Due to the complex constraints, more uncertain factors and critical real-time demand of path planning for unmanned combat aerial vehicle (UCAV, an approach of fast path planning based on Voronoi diagram and pre-evolution genetic algorithm (PEGA is proposed, which makes use of the principle of hierarchical path planning. First the Voronoi diagram is utilized to generate the initial paths and calculate the weight of the paths by considering the constraints. Then the optimal path is searched by using PEGA. Multiprocessors parallel computing techniques are used for PEGA to improve the traditional genetic algorithm and the optimal time is greatly reduced. Simulation results verify that the method of path planning is more favorable in the real-time operation. It can improve the adaptability of dynamic battlefield and unexpected threats for UCAV.

  8. Sustainable Energy Path

    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.

  9. On Hilbert space of paths

    A Hilbert space of paths, the elements of which are determined by trigonometric series, was proposed and used recently by Truman. This space is shown to consist precisely of all absolutely continuous paths ending in the origin with square-integrable derivatives

  10. Chromatic roots and hamiltonian paths

    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 is...

  11. Rainbow paths with prescribed ends

    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...

  12. Path Integral Simulations of Graphene

    Yousif, Hosam

    2007-10-01

    Some properties of graphene are explored using a path integral approach. The path integral method allows us to simulate relatively large systems using monte carlo techniques and extract thermodynamic quantities. We simulate the effects of screening a large external charge potential, as well as conductivity and charge distributions in graphene sheets.

  13. To Give Or Not To Give: A Step Towards Addressing The Heart Of Innovative Climates

    Livesay, Zackary Steven

    2013-01-01

    Innovative climates are largely affected by the relationships between the individualsinvolved. This thesis addresses the topic of trying to improve the quality ofrelationships by giving engineers some tools and principles to understand in order forthem to be able to contribute positively to a creative and productive atmosphere.Through the experiences drawn from universities both in India and Bhutan, thestudent tries to grasp some fundamental ideas about human values that can be sharedto other...

  14. Analysis gives the use he/she gives radioactive sources declared in disuse

    Presently work is carried out an analysis the different factors that impact in the possibility for application the radioactive sources declared in disuse in the oriental territory entities in Cuba. With the objective to define the feasibility application sources declared in disuse, valuing the technical characteristics, the requirements give radiological protection, convenience use in other technological processes and the cost for those localized ones in the territory

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

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

    2015-01-01

    proposed 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...

  16. Adaptive radar resource management

    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. Group theoretical approach to path integration on spheres

    The path integral over compact and non-compact spheres (denoted by Hα) is discussed. The short time propagator is decomposed in unitary irreducible representations of the corresponding transformation group G of Hα. Two cases are considered. For G ≅ Hα the Fourier analysis leads to an expansion in group characters. However, in the general case Hα ≅ G/H the decomposition gives an expansion in zonal spherical functions of G is contained in H. The path integral is performed using the orthogonality of the representations. The groups SO(n), SO(n - 1,1) SU(2) and SU(1,1) are considered. (author). 10 refs

  18. Pathways with PathWhiz.

    Pon, Allison; Jewison, Timothy; Su, Yilu; Liang, Yongjie; Knox, Craig; Maciejewski, Adam; Wilson, Michael; Wishart, David S

    2015-07-01

    PathWhiz (http://smpdb.ca/pathwhiz) is a web server designed to create colourful, visually pleasing and biologically accurate pathway diagrams that are both machine-readable and interactive. As a web server, PathWhiz is accessible from almost any place and compatible with essentially any operating system. It also houses a public library of pathways and pathway components that can be easily viewed and expanded upon by its users. PathWhiz allows users to readily generate biologically complex pathways by using a specially designed drawing palette to quickly render metabolites (including automated structure generation), proteins (including quaternary structures, covalent modifications and cofactors), nucleic acids, membranes, subcellular structures, cells, tissues and organs. Both small-molecule and protein/gene pathways can be constructed by combining multiple pathway processes such as reactions, interactions, binding events and transport activities. PathWhiz's pathway replication and propagation functions allow for existing pathways to be used to create new pathways or for existing pathways to be automatically propagated across species. PathWhiz pathways can be saved in BioPAX, SBGN-ML and SBML data exchange formats, as well as PNG, PWML, HTML image map or SVG images that can be viewed offline or explored using PathWhiz's interactive viewer. PathWhiz has been used to generate over 700 pathway diagrams for a number of popular databases including HMDB, DrugBank and SMPDB. PMID:25934797

  19. Geodesic flows on path spaces

    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.

  20. Adaptive skills

    Staša Stropnik; Jana Kodrič

    2013-01-01

    Adaptive skills are defined as a collection of conceptual, social and practical skills that are learned by people in order to function in their everyday lives. They include an individual's ability to adapt to and manage her or his surroundings to effectively function and meet social or community expectations. Good adaptive skills promote individual's independence in different environments, whereas poorly developed adaptive skills are connected to individual's dependency and with g...

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

    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...

  2. Path Dependent Option Pricing: the path integral partial averaging method

    Andrew Matacz

    2000-01-01

    In this paper I develop a new computational method for pricing path dependent options. Using the path integral representation of the option price, I show that in general it is possible to perform analytically a partial averaging over the underlying risk-neutral diffusion process. This result greatly eases the computational burden placed on the subsequent numerical evaluation. For short-medium term options it leads to a general approximation formula that only requires the evaluation of a one d...

  3. Pathways with PathWhiz

    Pon, Allison; Jewison, Timothy; Su, Yilu; Liang, Yongjie; Knox, Craig; Maciejewski, Adam; Wilson, Michael; Wishart, David S.

    2015-01-01

    PathWhiz (http://smpdb.ca/pathwhiz) is a web server designed to create colourful, visually pleasing and biologically accurate pathway diagrams that are both machine-readable and interactive. As a web server, PathWhiz is accessible from almost any place and compatible with essentially any operating system. It also houses a public library of pathways and pathway components that can be easily viewed and expanded upon by its users. PathWhiz allows users to readily generate biologically complex pa...

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

    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.

  5. Ask-Elle: an adaptable programming tutor for Haskell giving automated feedback

    Gerdes, Alex; Heeren, Bastiaan; Jeuring, J.T.; Binsbergen, Thomas van

    2015-01-01

    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

  6. Evaluating an Abbreviated Version of the Paths Curriculum Implemented by School Mental Health Clinicians

    Gibson, Jennifer E.; Werner, Shelby S.; Sweeney, Andrew

    2015-01-01

    When evidence-based prevention programs are implemented in schools, adaptations are common. It is important to understand which adaptations can be made while maintaining positive outcomes for students. This preliminary study evaluated an abbreviated version of the Promoting Alternative Thinking Strategies (PATHS) Curriculum implemented by…

  7. Adaptive Lighting

    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...... distributed 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...

  8. Freshwater paths across the ocean: molecular phylogeny of the frog Ptychadena newtoni gives insights into amphibian colonization of oceanic islands

    Measey, John G.; Vences, M.; Drewes, R. C.; Chiari, Y.; Melo, M.; Bourlès, Bernard

    2007-01-01

    Aim Amphibians are a model group for studies of the biogeographical origins of salt-intolerant taxa on oceanic islands. We used the Gulf of Guinea islands to explore the biogeographical origins of island endemism of one species of frog, and used this to gain insights into potential colonization mechanisms. Location Sao Tome and Principe, two of the four major islands in the Gulf of Guinea, West Africa, are truly oceanic and have an exceptionally high biodiversity. Methods Mitochondrial DNA is...

  9. The Internet's unexploited path diversity

    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.

  10. Q-Deformed Path Integral

    Chaichian, M.; Demichev, A. P.

    1993-01-01

    Using differential and integral calculi on the quantum plane which are invariant with respect to quantum inhomogeneous Euclidean group E(2)q , we construct path integral representation for the quantum mechanical evolution operator kernel of q-oscillator.

  11. Path summation: Achievements and goals

    The Proceedings of the Adriatico Research Conference on ''Path Integral Method with Applications'' held in Trieste, between 1-4 September 1987, includes 26 papers. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  12. Innovation paths in wind power

    Lema, Rasmus; Nordensvärd, Johan; Urban, Frauke;

    to the 1970s, but it has gained particular traction in recent years thus opening up new innovation paths. This paper explores the key features, similarities and differences in innovation paths in Denmark and Germany and sheds light on their main determinants. The paper shows that there are many...... Denmark and Germany have common national causes, while company-specific strategies also influence the innovation paths in significant ways. This raises important questions about the national specificity of innovation paths in wind power development. Finally, the paper briefly addresses the increasing......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...

  13. Adaptive positioner; Posicionador adaptativo

    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.

  14. Path-based Queries on Trajectory Data

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

    2014-01-01

    In traffic research, management, and planning a number of path-based analyses are heavily used, e.g., for computing turn-times, evaluating green waves, or studying traffic flow. These analyses require retrieving the trajectories that follow the full path being analyzed. Existing path queries cannot...... sufficiently support such path-based analyses because they retrieve all trajectories that touch any edge in the path. In this paper, we define and formalize the strict path query. This is a novel query type tailored to support path-based analysis, where trajectories must follow all edges in the path...... 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...

  15. Phase Diagram of Optimal Paths

    Hansen, Alex; Kertesz, Janos

    2004-01-01

    We show that choosing appropriate distributions of the randomness, the search for optimal paths links diverse problems of disordered media like directed percolation, invasion percolation, directed and non-directed spanning polymers. We also introduce a simple and efficient algorithm, which solves the d-dimensional model numerically in order N^(1+d_f/d) steps where d_f is the fractal dimension of the path. Using extensive simulations in two dimensions we identify the phase boundaries of the di...

  16. Flows driven by rough paths

    Bailleul, Ismael

    2012-01-01

    We show in this work how the familiar Taylor formula can be used in a simple way to reprove from scratch the main existence and well-posedness results from rough paths theory; the explosion question and Taylor expansion are also dealt with. Unlike other approaches, we work mainly with flows of maps rather than with paths. We illustrate our approach by proving a well-posedness result for some mean field rough differential equation.

  17. Fieldwork on selected educational paths

    Charzyński, Przemysław; Podgórski, Zbigniew; Brykała, Dariusz; Zaparucha, Aleksandra; Barwińska, Sylwia

    2015-01-01

    The paper concerns the possibilities of using educational paths as one form of fieldwork for activating learning. Educational paths, also fostering informal education of a wider society, allow for conducting direct observations and measurements, and are a great source of knowledge about the immediate environment. This form of learning enables interdisciplinary education, combining geography with other school subjects. To become a useful tool in education, however, an educationa...

  18. Formal language constrained path problems

    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.

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

    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...... simple self-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...

  20. Greater Emotional Gain from Giving in Older Adults: Age-Related Positivity Bias in Charitable Giving.

    Bjälkebring, Pär; Västfjäll, Daniel; Dickert, Stephan; Slovic, Paul

    2016-01-01

    Older adults have been shown to avoid negative and prefer positive information to a higher extent than younger adults. This positivity bias influences their information processing as well as decision-making. We investigate age-related positivity bias in charitable giving in two studies. In Study 1 we examine motivational factors in monetary donations, while Study 2 focuses on the emotional effect of actual monetary donations. In Study 1, participants (n = 353, age range 20-74 years) were asked to rate their affect toward a person in need and then state how much money they would be willing to donate to help this person. In Study 2, participants (n = 108, age range 19-89) were asked to rate their affect toward a donation made a few days prior. Regression analysis was used to investigate whether or not the positivity bias influences the relationship between affect and donations. In Study 1, we found that older adults felt more sympathy and compassion and were less motivated by negative affect when compared to younger adults, who were motivated by both negative and positive affect. In Study 2, we found that the level of positive emotional reactions from monetary donations was higher in older participants compared to younger participants. We find support for an age-related positivity bias in charitable giving. This is true for motivation to make a future donation, as well as affective thinking about a previous donation. We conclude that older adults draw more positive affect from both the planning and outcome of monetary donations and hence benefit more from engaging in monetary charity than their younger counterparts. PMID:27378966

  1. Asteroidal Quadruples in non Rooted Path Graphs

    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.

  2. Balanced Path Routing and Detection Mechanism for Wireless Sensor Networks

    T.Shanmuga priya

    2013-10-01

    Full Text Available - An Enhanced Dijkstra’s algorithm is presented in this paper. In this proposed approach, a new form of Balanced Path Routing technique is used in which the data send from source node is being transferred to the alternate node and then pass through the nodes to reach the destination. This prevents cuts in between the nodes and gives prior estimation of the shortest route path from source to destination. In Enhanced Dijkstra’s algorithm, the packet delivery ratio is maintained at 80% even when the number of nodes gets increased. This finding indicates that proposed method guarantees reliable communication in wireless sensor networks. The simulation results show the best shortest path with better transmission time.

  3. Optimum Strategies for Selecting Descent Flight-Path Angles

    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.

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

    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).

  5. Adaptive Lighting

    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...... the investigations of lighting scenarios carried out in two test installations: White Cube and White Box. The test installations are discussed as large-scale experiential instruments. In these test installations we examine what could potentially occur when light using LED technology is integrated and...

  6. Rethinking the social and cultural dimensions of charitable giving

    Bajde, Domen

    2009-01-01

    socially symbolic dimensions of charitable giving are critically examined in light of postmodern consumer culture and the recent social corporate responsibility trends. By openly engaging the proposed complexities of gift-giving, our vocabulary and understanding of postmodern giving can be revised so as to...

  7. Device and proceeding of dry storage for materials giving out heat

    The invention concerns a device and a proceeding of dry storage for material giving out heat. It is adapted to radioactive waste storage. Radioactive waste can be packaged in containers and then put in a well with a concrete enclosure. This well has an entrance opening for cold air in its low part, and an other opening in its high part to allow to evacuate the hot fluid

  8. Adaptive skills

    Staša Stropnik

    2013-02-01

    Full Text Available Adaptive skills are defined as a collection of conceptual, social and practical skills that are learned by people in order to function in their everyday lives. They include an individual's ability to adapt to and manage her or his surroundings to effectively function and meet social or community expectations. Good adaptive skills promote individual's independence in different environments, whereas poorly developed adaptive skills are connected to individual's dependency and with greater need for control and help with everyday tasks. Assessment of adaptive skills is often connected to assessment of intellectual disability, due to the reason that the diagnosis of intellectual disability includes lower levels of achievements on standardized tests of intellectual abilities as well as important deficits in adaptive skills. Assessment of adaptive behavior is a part of standard assessment battery with children and adults with different problems, disorders or disabilities that affect their everyday functioning. This contribution also presents psychometric tools most regularly used for assessment of adaptive skills and characteristics of adaptive skills with individual clinical groups.

  9. ADAPT Dataset

    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...

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

    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. PMID:22985116

  11. Majorana and the path-integral approach to Quantum Mechanics

    Esposito, S

    2006-01-01

    We give, for the first time, the English translation of a manuscript by Ettore Majorana, which probably corresponds to the text for a seminar delivered at the University of Naples in 1938, where he lectured on Theoretical Physics. Some passages reveal a physical interpretation of the Quantum Mechanics which anticipates of several years the Feynman approach in terms of path integrals, independently of the underlying mathematical formulation.

  12. Perfect Matchings in Lattice Animals and Lattice Paths with Constraints

    Došlić, Tomislav

    2005-01-01

    In the first part of this paper it is shown how to use ear decomposition techniques in proving existence and establishing lower bounds to the number of perfect matchings in lattice animals. A correspondence is then established between perfect matchings in certain classes of benzenoid graphs and paths in the rectangular lattice that satisfy certain diagonal constraints. This correspondence is used to give explicit formulas for the number of perfect matchings in hexagonal benzenoid graphs and t...

  13. Rings of quotients of incidence algebras and path algebras

    Esparza, Eduardo Ortega

    2006-01-01

    We compute the maximal right/left/symmetric rings of quotients of finite dimensional incidence and graph algebras. We show that these rings of quotients are Morita equivalent to incidence algebras and path algebras respectively, with respect to simpler, well determined partially ordered sets and...... finite quivers, respectively. The geometric background of these algebras gives us an intuitive idea of the construction of their maximal ring of quotients....

  14. Modeling Adaptive Educational Methods with IMS Learning Design

    Specht, Marcus; Burgos, Daniel

    2007-01-01

    The paper describes a classification system for adaptive methods developed in the area of adaptive educational hypermedia based on four dimensions: What components of the educational system are adapted? To what features of the user and the current context does the system adapt? Why does the system adapt? How does the system get the necessary information? Based on this taxonomy several classical methods of adaptive educational hypermedia are classified. In a second step the paper gives an over...

  15. Some practical crack path examples

    Les P. Pook

    2007-07-01

    Full Text Available It is well known that many engineering structures and components, as well as consumer items, contain cracks or crack-like flaws. It is widely recognised that crack growth must be considered both in designand in the analysis of failures. The complete solution of a crack growth problem includes determination of the crack path. Macroscopic aspects of crack paths have been of industrial interest for a very long time.At the present state of the art the factors controlling the path taken by a crack are not completely understood.Eight brief case studies are presented. These are taken from the author’s professional and personal experience of macroscopic crack paths over many years. They have been chosen to illustrate various aspects of crack paths. One example is in a component from a major structure, three examples are in laboratory specimens, and four are in nuisance failures. Such nuisance failures cause, in total, a great deal of inconvenience and expensive, but do not normally receive much publicity.

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

    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

  17. Calculating Least Risk Paths in 3d Indoor Space

    Vanclooster, A.; De Maeyer, Ph.; Fack, V.; Van de Weghe, N.

    2013-08-01

    Over the last couple of years, research on indoor environments has gained a fresh impetus; more specifically applications that support navigation and wayfinding have become one of the booming industries. Indoor navigation research currently covers the technological aspect of indoor positioning and the modelling of indoor space. The algorithmic development to support navigation has so far been left mostly untouched, as most applications mainly rely on adapting Dijkstra's shortest path algorithm to an indoor network. However, alternative algorithms for outdoor navigation have been proposed adding a more cognitive notion to the calculated paths and as such adhering to the natural wayfinding behaviour (e.g. simplest paths, least risk paths). These algorithms are currently restricted to outdoor applications. The need for indoor cognitive algorithms is highlighted by a more challenged navigation and orientation due to the specific indoor structure (e.g. fragmentation, less visibility, confined areas…). As such, the clarity and easiness of route instructions is of paramount importance when distributing indoor routes. A shortest or fastest path indoors not necessarily aligns with the cognitive mapping of the building. Therefore, the aim of this research is to extend those richer cognitive algorithms to three-dimensional indoor environments. More specifically for this paper, we will focus on the application of the least risk path algorithm of Grum (2005) to an indoor space. The algorithm as proposed by Grum (2005) is duplicated and tested in a complex multi-storey building. The results of several least risk path calculations are compared to the shortest paths in indoor environments in terms of total length, improvement in route description complexity and number of turns. Several scenarios are tested in this comparison: paths covering a single floor, paths crossing several building wings and/or floors. Adjustments to the algorithm are proposed to be more aligned to the

  18. Hamiltonian paths on directed grids

    Hujter, Mihály; Kaszanyitzky, András

    2015-01-01

    Our studies are related to a special class of FASS-curves, which can be described in a node-rewriting Lindenmayer-system. These ortho-tile (or diagonal) type recursive curves inducing Hamiltonian paths. We define a special directed graph on a rectangular grid, and we enumerate all Hamiltonian paths on this graph. Our formulas are strongly related to both the Fibonacci numbers and the domino tilings of chessboards. The constructability of the regular $17$-gon with straightedge and compass is a...

  19. Path Integrals in Quantum Mechanics

    Jean Zinn-Justin's textbook Path Integrals in Quantum Mechanics aims to familiarize the reader with the path integral as a calculational tool in quantum mechanics and field theory. The emphasis is on quantum statistical mechanics, starting with the partition function Tr exp(-β H) and proceeding through the diffusion equation to barrier penetration problems and their semiclassical limit. The 'real time' path integral is defined via analytic continuation and used for the path-integral representation of the nonrelativistic S-matrix and its perturbative expansion. Holomorphic and Grassmannian path integrals are introduced and applied to nonrelativistic quantum field theory. There is also a brief discussion of path integrals in phase space. The introduction includes a brief historical review of path integrals, supported by a bibliography with some 40 entries. As emphasized in the introduction, mathematical rigour is not a central issue in the book. This allows the text to present the calculational techniques in a very readable manner: much of the text consists of worked-out examples, such as the quartic anharmonic oscillator in the barrier penetration chapter. At the end of each chapter there are exercises, some of which are of elementary coursework type, but the majority are more in the style of extended examples. Most of the exercises indeed include the solution or a sketch thereof. The book assumes minimal previous knowledge of quantum mechanics, and some basic quantum mechanical notation is collected in an appendix. The material has a large overlap with selected chapters in the author's thousand-page textbook Quantum Field Theory and Critical Phenomena (2002 Oxford: Clarendon). The stand-alone scope of the present work has, however, allowed a more focussed organization of this material, especially in the chapters on, respectively, holomorphic and Grassmannian path integrals. In my view the book accomplishes its aim admirably and is eminently usable as a textbook

  20. Multiple paths in complex tasks

    Galanter, Eugene; Wiegand, Thomas; Mark, Gloria

    1987-01-01

    The relationship between utility judgments of subtask paths and the utility of the task as a whole was examined. The convergent validation procedure is based on the assumption that measurements of the same quantity done with different methods should covary. The utility measures of the subtasks were obtained during the performance of an aircraft flight controller navigation task. Analyses helped decide among various models of subtask utility combination, whether the utility ratings of subtask paths predict the whole tasks utility rating, and indirectly, whether judgmental models need to include the equivalent of cognitive noise.

  1. Spin Observables and Path Integrals

    López, J A

    2000-01-01

    We discuss the formulation of spin observables associated to a non-relativistic spinning particles in terms of grassmanian differential operators. We use as configuration space variables for the pseudo-classical description of this system the positions $x$ and a Grassmanian vector quantum amplitudes as path integrals in this superspace. We compute the quantum action necessary for this description including an explicit expression for the boundary terms. Finally we shown how for simple examples, the path integral may be performed in the semi-classical approximation, leading to the correct quantum propagator.

  2. Strings, paths, and standard tableaux

    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.

  3. Arithmetic area for m planar Brownian paths

    Desbois, Jean

    2012-01-01

    We pursue the analysis made in [1] on the arithmetic area enclosed by m closed Brownian paths. We pay a particular attention to the random variable S{n1,n2, ...,n} (m) which is the arithmetic area of the set of points, also called winding sectors, enclosed n1 times by path 1, n2 times by path 2, ...,nm times by path m. Various results are obtained in the asymptotic limit m->infinity. A key observation is that, since the paths are independent, one can use in the m paths case the SLE information, valid in the 1-path case, on the 0-winding sectors arithmetic area.

  4. Economics of adaptation to climate change

    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

  5. When breastfeeding is unsuccessful - mothers' experiences after giving up breastfeeding

    Larsen, Jette Schilling; Kronborg, Hanne

    2013-01-01

    Some mothers have to give up breastfeeding even though they want to breastfeed. To give up breastfeeding can be a sensitive issue in a time when breastfeeding is promoted as the healthiest for mother and child. The aim of this study was to describe mothers’ experiences after they gave up breastfe......Some mothers have to give up breastfeeding even though they want to breastfeed. To give up breastfeeding can be a sensitive issue in a time when breastfeeding is promoted as the healthiest for mother and child. The aim of this study was to describe mothers’ experiences after they gave up...... breastfeeding even though they intended to breastfeed. A qualitative social constructive approach was used to describe mothers’ experiences after giving up breastfeeding. Danish first-time mothers who had expected and wanted to breastfeed were interviewed four months after birth. The interviews were analysed by...... aware that mothers who have to give up breastfeeding need special attention and support....

  6. Montreal Protocol: The Gift that Keeps on Giving

    Reifsnyder, D. A.

    2012-12-01

    be followed by developing countries. The question was, could we do it? And if we could, how could we get others developed countries and then developing countries on side? After our internal discussions, State and EPA convened a workshop with U.S. stakeholders from the private sector and the environmental community. To our delight, both groups thought the United States should take the initiative. In retrospect, the winds were favorable - 2007 marked the 25th Anniversary of the Montreal Protocol and many wanted to celebrate it with something significant. The private sector felt that it could meet an accelerated timetable for phasing out HCFCs - the technology was there. It was also clear that money in the Montreal Protocol Multilateral Fund had begun to decline with the developing country phaseout of CFCs and would decline even more steeply unless a new basis were found to continue it. But favorable winds do not always make for a smooth sail - and path to the accelerated phaseouts of 2007 proved challenging. At the time, practically no one thought the effort would succeed. Still, we did succeed. Yet even then it took time to for many to appreciate the significant benefits for the climate system, beyond the benefits to the stratospheric ozone layer. In fact, the continuing story of the Montreal Protocol is one of the gift that keeps on giving.

  7. Determinants of weighted path matrices

    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.

  8. Adaptive Gas Metal Arc (GMA) Welder

    Nachev, G.; Petkov, B.; Blagoev, L.; Tsankarski, I.

    1984-02-01

    Unlike NC machine-tools, where the tool path is primary and the product shape results from it, in arc welding the product is primary, and the welder - human or robot - has to contend with poor fitups, bad preparations, inexact positionning etc. All this means one thing - adaptivity. The axtent to which this is reasonable is discussed, and then a research project, conducted at IICR with the aim to create an adaptive GMA robot, is presented.

  9. Promoting social emotional learning in Chinese schools: a feasibility study of PATHS implementation in Hong Kong

    Chi-Ming Kam; Lance Wai-lap Wong; Kennis Mei-sze Fung

    2011-01-01

    Social emotion learning (SEL) can be taught in schools. The present report describes a pilot trial of the PATHS Curriculum, a US developed evidence-based SEL program, among schools in Hong Kong SAR (China). Three elementary schools, 318 students in 12 first grade classrooms, participated in the study. The first grade PATHS lessons were adapted and translated into Chinese. Twelve teachers learned and adopted these lessons in their teaching. Students in these classrooms learned about different ...

  10. Ambiguous Adaptation

    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 and...... reciprocal adaptation of informal governance structure create ambiguity in situations of contingencies, which, subsequently, increases the likelihood of premature relationship termination. Using a large sample of exchange relationships in the global service provider industry, we find support for a hypothesis...