Analytic Exploration of Safe Basins in a Benchmark Problem of Forced Escape

The paper presents an analytic approach for predicting the safe basins (SB) in a plane of initial conditions (IC) for escape of classical particle from the potential well under harmonic forcing. The solution is based on the approximation of isolated resonance, which reduces the dynamics to conservative flow on a two-dimensional resonance manifold (RM). Such a reduction allows easy distinction between escaping and non-escaping ICs. As a benchmark potential, we choose a common parabolic-quartic well with truncation at varying energy levels. The method allows accurate predictions of the SB boundaries for relatively low forcing amplitudes. The derived SBs demonstrate an unexpected set of properties, including decomposition into two disjoint zones in the IC plane for a certain range of parameters. The latter peculiarity stems from two qualitatively different escape mechanisms on the RM. For higher forcing values, the accuracy of the analytic predictions decreases to some extent due to the inaccuracies of the basic isolated resonance approximation, but mainly due to the erosion of the SB boundaries caused by the secondary resonances. Nevertheless, even in this case the analytic approximation can serve as a viable initial guess for subsequent numeric estimation of the SB boundaries.

Numeric estimation of resource requirements for a practical polarization-frame alignment scheme for quantum key distribution (QKD)

Owing to physical orientations and birefringence effects, practical quantum information protocols utilizing optical polarization need to handle misalignment between preparation and measurement reference frames. For any such capable system, an important question is how many resources – for example, measured single photons – are needed to reliably achieve alignment precision sufficient for the desired quantum protocol. Here, we study the performance of a polarization-frame alignment scheme used in prior laboratory and field quantum key distribution (QKD) experiments by performing Monte Carlo numerical simulations. The scheme utilizes, to the extent possible, the same single-photon-level signals and measurements as for the QKD protocol being supported. Even with detector noise and imperfect sources, our analysis shows that only a small fraction of resources from the overall signal – a few hundred photon detections, in total – are required for good performance, restoring the state to better than 99% of its original quality.

The effect of specific emotions on conformity

Various factors can impact the level to which people conform to other?s. An important, yet unanswered question is how emotions could influence conformity levels. We predicted that specific emotions, which embody an underlying appraisal of uncertainty about the world, would lead people to feel more uncertain and subsequently more susceptible to others? influence. To test this hypothesis, participants (N = 78) induced to feel sad, happy or angry had to perform a highly ambiguous numeric estimation task. In half of the trials, participants were presented with additional estimates ostensibly provided by three other individuals, and were left free to use or disregard them when completing the task. As expected, participants in the sadness condition (an emotion associated with a low certainty appraisal) showed more conformity than those in the anger or happiness conditions (emotions associated with a high certainty appraisal). Taken together, our findings suggest that being in an emotional state characterized by uncertainty can increase people?s sensitivity to others? informational influences resulting in a higher level of conformity.

Pump eflciency of lymphatic vessels: numeric estimation

A model of lymph flow in the human lymphatic system in the quasi-one-dimensional approach has been created and investigated under different conditions. The model includes an implementation of contractions and valve influence on lymph flow. We consider contractions of lymphatic vessels and their influence on resulting flow in the whole network of lymphatic vessels and lymph nodes. We have investigated flow with zero pressure gradient and have found parameters, which influence the efficiency of contractions most significantly.

QoS Based Discovery and Service Provider System

We propose a two-step, context-based semantic approach to the problem of matching and ranking Web services for possible service composition. Semantic understanding of Web services may provide added value by identifying new possibilities for compositions of services and context-based semantic. The semantic matching ranking approach is unique since it provides the Web service designer with an explicit numeric estimation of the extent to which a possible composition. This process consists of multiple services that can be executed in sequence or in a parallel process. Given a service request, a set of candidates (available services and service patterns) is dynamically generated layer by layer from inputs to outputs of this request. For each layer, the algorithm traverses a priori search space which is a set of service patterns from historical solutions, then it searches available services from the repositories. That means each layer contains all services and service patterns that can be executed with a set of outputs provided by previous layers. The search process terminates until all the outputs of a request are obtained.

Calibrating Uncertainty: Commonalities in the Estimation of Numeric Variability Versus Spatial Prediction

To assess whether there may be a common ability related to the understanding and calibration of instance variability and mean behavior, participants performed spatial prediction and numeric estimation tasks. In the first task, participants experienced variability in a set of spatial trajectories whose endpoints they predicted along with a central mean. In the second task, they experienced variability in a set of random numbers whose mean and variability they estimated. For both tasks, estimated variability was compared with the true variability of instances to derive measures of bias (e.g., over-or under-estimation) and precision. Correlations between these estimates across the two experiments revealed mixed evidence for a common ability to estimate variability, but suggested similar performance when estimating mean behavior. Implications for individual differences and interventions are discussed.

Strcs: A Command for Fitting Flexible Parametric Survival Models on the Log-hazard Scale

In this article, we describe strcs, a user-written command for fitting flexible parametric survival models on the log-hazard scale. strcs is an extension of the user-written stgenreg command (Crowther and Lambert, 2013b, Journal of Statistical Software 53(12): 1–17), which fits general parametric models with user-defined hazard functions using numerical integration. strcs implements a two-step method that incorporates both analytical and numerical integration to estimate the cumulative hazard function required for the log-likelihood function. This method improves the accuracy of the fully numeric estimation implemented in stgenreg. Time-dependent effects can be incorporated, and excess mortality models can be fit by using the available options. We also describe some of the extensive postestimation commands that are easily implemented after fitting an strcs model.