Information Acquisition and Time-Risk Preference

Distances are fundamental primitives whose choice significantly impacts the performances of algorithms in machine learning and signal processing. However selecting the most appropriate distance for a given task is an endeavor. Instead of testing one by one the entries of an ever-expanding dictionary of {\em ad hoc} distances, one rather prefers to consider parametric classes of distances that are exhaustively characterized by axioms derived from first principles. Bregman divergences are such a class. However fine-tuning a Bregman divergence is delicate since it requires to smoothly adjust a functional generator. In this work, we propose an extension of Bregman divergences called the Bregman chord divergences. This new class of distances does not require gradient calculations, uses two scalar parameters that can be easily tailored in applications, and generalizes asymptotically Bregman divergences.

The profitability of a new technology is rarely known with certainty at its announcement date. Consequently, prior to making an adoption decision it behooves the firm considering the adoption of this innovation to reduce the level of uncertainty associated with its profitability. The firm accomplishes this by sequentially gathering information, updating its prior estimate of profitability in a Bayesian manner. Quantifying the uncertainty regarding the innovation permits application of dynamic programming techniques: criteria are derived which tell the firm when to stop collecting information and make the adoption decision. It will be shown that it is optimal for the firm to continue to collect information until its estimate of profitability crosses one of two thresholds: upon crossing the upper threshold the firm adopts the technology, whereas the firm rejects the technology if the lower threshold is crossed. The model predicts that even the manager who behaves optimally will occasionally adopt unprofitable technologies and reject profitable ones.

In this paper, we discuss some properties of optimal consideration set in binary state continuous-action rational inattention decision problems. First, we show that it is the form of the utility function that determines the form of posterior distribution, i.e. whether it is a binary distribution or a triple or quadruple distribution, etc. Besides, we will also show that the posterior distribution may not be resulted after information acquisition in some circumstances. Second, we show that the optimal consideration set is essentially the optimal action strategies. Therefore, without further conditions, the rational inattention decision model is unidentifiable. Third, in order to identify the rational inattention decision model, we introduce another condition to the model. The discrete actions after information acquisition that satisfy the endogenously-determined probability (optimal action strategies) should satisfy the properties of probabilities, and therefore the discrete actions should also follow an exogenous probability distribution. This idea is tested by an example with quadratic utility function. Through this example, we find that under this condition, the optimal consideration set can be identified. The elements in the optimal consideration set, or equivalently the discrete signals after information acquisition, exhibit a curve or curves.

We develop an operational approach for reconstructing the quantum theory of qubit systems from elementary rules on information acquisition. The focus lies on an observerOinterrogating a systemSwith binary questions andS's state is taken asO's `catalogue of knowledge' aboutS. The mathematical tools of the framework are simple and we attempt to highlight all underlying assumptions. Four rules are imposed, asserting (1) a limit on the amount of information available toO; (2) the mere existence of complementary information; (3)O's total amount of information to be preserved in-between interrogations; and, (4)O's `catalogue of knowledge' to change continuously in time in-between interrogations and every consistent such evolution to be possible. This approach permits a {\it constructive} derivation of quantum theory, elucidating how the ensuing independence, complementarity and compatibility structure ofO's questions matches that of projective measurements in quantum theory, how entanglement and monogamy of entanglement, non-locality and, more generally, how the correlation structure of arbitrarily many qubits and rebits arises. The rules yield a reversible time evolution and a quadratic measure, quantifyingO's information aboutS. Finally, it is shown that the four rules admit two solutions for the simplest case of a single elementary system: the Bloch ball and disc as state spaces for a qubit and rebit, respectively, together with their symmetries as time evolution groups. The reconstruction for arbitrarily many qubits is completed in a companion paper [P. A. Höhn and C. S. P. Wever, Phys. Rev. A 95 (2017) 012102] where an additional rule eliminates the rebit case. This approach is inspired by (but does not rely on) the relational interpretation and yields a novel formulation of quantum theory in terms of questions.

Individuals with peripheral arterial disease (PAD) have a 3- to 6-fold increased risk of coronary heart disease and stroke compared to those without PAD. We documented physician-reported practice behavior, knowledge, and attitudes regarding atherosclerotic risk factor reduction in patients with PAD. National physician survey. General internists (N = 406), family practitioners (N = 435), cardiologists (N = 473), and vascular surgeons (N = 264) randomly identified using the American Medical Association's physician database. Physicians were randomized to 1 of 3 questionnaires describing a) a 55- to 65-year-old patient with PAD; b) a 55- to 65-year-old patient with coronary artery disease (CAD), or c) a 55- to 65-year-old patient without clinically evident atherosclerosis (no disease). A mailed questionnaire was used to compare physician behavior, knowledge, and attitude regarding risk factor reduction for each patient. Rates of prescribed antiplatelet therapy were significantly lower for the patient with PAD than for the patient with CAD. Average low-density lipoprotein levels at which physicians "almost always" initiated lipid-lowering drugs were 121.6 +/- 23.5 mg/dL, 136.3 +/- 28.9 mg/dL, and 149.7 +/- 24.4 mg/dL for the CAD, PAD, and no-disease patients, respectively (P <.001). Physicians stated that antiplatelet therapy (P <.001) and cholesterol-lowering therapy (P <.001) were extremely important significantly more often for the CAD than for the PAD patient. Perceived importance of risk factor interventions was highly correlated with practice behavior. Compared to other specialties, cardiologists had lowest thresholds, whereas vascular surgeons had the highest thresholds for initiating cholesterol-lowering interventions for the patient with PAD. Cardiologists were significantly more likely to report "almost always" prescribing antiplatelet therapy for the patient with PAD than were all other physicians. Deficiencies in physician knowledge and attitudes contribute to lower rates of atherosclerotic risk factor reduction for patients with PAD. Reversing these deficiencies may reduce the high rates of cardiovascular morbidity and mortality associated with PAD.

In this work the distribution of interoccurrence times between earthquakes in aftershock sequences is analyzed and a model based on a nonhomogeneous Poisson (NHP) process is proposed to quantify the observed scaling. In this model the generalized Omori's law for the decay of aftershocks is used as a time-dependent rate in the NHP process. The analytically derived distribution of interoccurrence times is applied to several major aftershock sequences in California to confirm the validity of the proposed hypothesis.

Stochastic studies of passivity breakdown

Playing action video games enhances visual motion perception. However, there is psychophysical evidence that action video games do not improve motion sensitivity for translational global moving patterns presented in fovea. This study investigates global motion perception in action video game players and compares their performance to that of non-action video game players and non-video game players. Stimuli were random dot kinematograms presented in the parafovea. Observers discriminated the motion direction of a target random dot kinematogram presented in one of the four visual quadrants. Action video game players showed lower motion coherence thresholds than the other groups. However, when the task was performed at threshold, we did not find differences between groups in terms of distributions of reaction times. These results suggest that action video games improve visual motion sensitivity in the near periphery of the visual field, rather than speed response.

싸리수염진딧물(Aulacorthum solani)의 온도별 발육상을 조사하기 위해 <TEX>$12.5^{\circ}C$</TEX>에서 <TEX>$27.5^{\circ}C$</TEX>까지 <TEX>$2.5^{\circ}C$</TEX> 간격으로 7개 온도에서 조사를 하였으며, 상대습도는 <TEX>$65{\pm}5%$</TEX>, 광주기는 16L:8D 조건으로 처리하였다. 일반적으로 진딧물의 약충 단계는 1령<TEX>${\sim}$</TEX>4령까지로 구분하나 본 연구에서는 1<TEX>${\sim}$</TEX>2령과 3<TEX>${\sim}$</TEX>4령으로 구분하였다. 대부분의 온도에서 사망률은 1<TEX>${\sim}$</TEX>2령과 3<TEX>${\sim}$</TEX>4령 약충이 유사하였으나, <TEX>$27.5^{\circ}C$</TEX>에서는 오히려 3<TEX>${\sim}$</TEX>4령의 사망률이 66.7%로 대부분을 차지하였다. 온도별 발육기간은 <TEX>$12.5^{\circ}C$</TEX>에서 16.9일로 가장 길었고 온도가 상승함에 따라 점차 짧아져 <TEX>$22.5^{\circ}C$</TEX>에서는 6.6일로 가장 짧았으나, <TEX>$25^{\circ}C$</TEX>에서는 오히려 7.4일로 발육 기간이 길어지는 양상을 보였다. 약충의 발육영점온도는 <TEX>$0.08^{\circ}C$</TEX>이고, 유효적산온도는 162.8일도였다. 각 온도별 발육률은 변형된 Sharpe와 DeMichele의 비선형 모형에 잘 적합 되었다. 발육단계별 발육기간을 표준화하여 누적시킨 값을 3개의 변수를 갖는 Weibull function에 적용했을 때 1<TEX>${\sim}$</TEX>2령 < 3<TEX>${\sim}$</TEX>4령 < 전체 약충 순으로 발육기간이 짧아지는 경향을 보여 주었고, <TEX>$r^2$</TEX>는 0.86<TEX>${\sim}$</TEX>0.91로 나타났다. The development of Aulacorthum solani (Kaltenbach) was studied at temperatures ranging from 12.5 to <TEX>$27.5^{\circ}C$</TEX> under <TEX>$65{\pm}5%$</TEX> RH, and a photoperiod of 16:8 (L:D). Mortality of <TEX>$1st{\sim}2nd$</TEX> nymph was higher than that of <TEX>$3rd{\sim}4th$</TEX> nymph at the most temperature ranges whereas at high temperature of <TEX>$27.5^{\circ}C$</TEX>, more <TEX>$3{\sim}4th$</TEX> nymph stage individuals died. The total developmental time ranged from 16.9 days at <TEX>$12.5^{\circ}C$</TEX> to 6.6days at <TEX>$22.5^{\circ}C$</TEX>, suggesting that higher the temperature, faster the development. However, at higher temperature of <TEX>$25^{\circ}C$</TEX> the development took 7.4 days. The lower developmental threshold temperature and effective accumulative temperatures for the total immature stage were <TEX>$0.08^{\circ}C$</TEX> and 162.8 day-degreeslated development. The nonlinear shape of temperature rewas well described by the modified Sharpe and DeMichele model. When the normalized cumulative frequency distributions of developmental times for each life stage were fitted to the three-parameter Weibull function, attendance of shortened developmental times was apparent with in <TEX>$1{\sim}2nd$</TEX> nymph, <TEX>$3{\sim}4th$</TEX> nymph, and total nymph stages in descending order. The coefficient of determination <TEX>$r^2$</TEX> ranged between 0.86 and 0.91.

BackgroundOne of the tests to evaluate cognitive decline is the Montreal Cognitive Assessment (MoCA), as a result, various technological developments have automated and digitized this test. Some of these systems present the test only in its digitalized form, while others integrate virtual reality and artificial intelligence with sophisticated signal processing methods that take into account the information from each item on the test to obtain systems that support diagnosis for professionals in this field.This type of system is contributing to the counterbalance of the expected scenario for the year 2050, according to the World Health Organization, which predicts that 140 million people will suffer from dementia.MethodIn this research, we present an automatic method based on image quality to obtain the illustrations made by patients during the visuospatial and executive function tests of the Montreal Cognitive Assessment (MoCA). Specifically, this method performs an automatic analysis and image processing that identifies the illustration with the best focus and quality for each of the three tests: Trail Making, Cube, and Clock.ResultThis optimization in the acquisition of information in cognitive domains, both in visuoconstructional skills and executive functions, provides robustness to our interactive web platform. In addition, when performing the MoCA test, the patient can save an estimated time between 50% and 70% by being able to capture and save the images immediately.This method avoids the most common problems when capturing images, such as having low‐quality images due to being captured in environments where with too low or too bright lighting, as well as instability in the movement of capture device.ConclusionFor the test database, the automatic scoring of each MoCA item and the score set for each of the three illustrations by the specialist, the results of our web application are obtained with 100% accuracy and equal to the evaluations carried out by specialists.The Web platform stores the tests performed so that the specialist doctor can analyze them and continuously monitor patients. This information is managed by the doctor and can be consulted by the patient's caregiver or family member.

ABSTRACTThe variability of occurrence rate of heavy precipitation (HPOR) across China was analysed to examine if the change in heavy precipitation satisfied the stationarity assumption.HPORobtained by peaks‐over‐threshold (POT) sampling can be interpreted as a realisation of a point process, which can be represented as a Poisson process. A number of methods, including kernel density estimation method, Cox regression model, Poisson regression model and Generalized Additive Models for Location, Scale, and Shape (GAMLSS), were used to evaluate the nonstationarity inHPOR. Nonstationarity was also assessed forHPORdefined by different thresholds which indicate different levels of severity of heavy precipitation. Our results indicated that: (1)HPORin northwestern China, a typical arid region, is subject to the most uneven temporal distribution and a significantly increasing trend in terms of inter‐annual variability. Moreover, this uneven temporal distribution is increasing for greater heavy precipitation events defined by higher percentiles, and the changing pattern is opposite in eastern, central and southwestern China; (2) the seasonal variability ofHPORis significantly related to climate indices during the year, which shows that theHPORis not independent and exhibits nonstationary with seasonality. However, as the thresholds increase, the impacts of climate indices onHPORare found to be weakening; (3) the annual number of greater heavy precipitation is subject to over‐dispersion, however, under‐dispersion can be identified for the annual number of heavy precipitation events defined by lower thresholds. Higher Southern Oscillation Index (SOI) and Pacific Decadal Oscillation (PDO) may trigger an increase in the frequency of heavy precipitation in northeastern and eastern China. These findings show the challenges of flood preventions and water resources management in a changing climate.

Tunable Diode Laser Absorption Spectroscopy (TDLAS) applies optical method to realize fast and non-contact detection. This technology has the advantages of high resolution and high sensibility, and been widely employed in atmosphere environment detection in recent years. This paper mainly introduces how TDLAS is applied to detect the vehicle exhaust, to determine the content of CO, CO2, NO and alkanes etc. Firstly, the principle of TDLAS is Lambert-Beer's law. It is based on the specific spectral fingerprint characteristics of different gases to detect the gas composition. In the same time, the light intensity is attenuated by molecular absorption, which is used to accurately analyze the density of gas. There are two ways to achieve. One is direct-absorption way, whose configuration and signal processing are simple, results have no need to be demarcated. The other is wavelength-modulation way, which has high resolution and low threshold. The selection of absorption spectral line needs not only to adapt the central wavelength of laser and responding wavelength of detector, but also to avoid the crossed spectral line of different gas to improve the precision of detection. Secondly, TDLAS system includes three parts, which are signal generation, signal detection and signal processing. Finally, TDLAS is compared with other spectral detection technologies in the aspect of sensitivity, character of working, applicable kinds of gas, in order to highlight the application scope of each technology.

By exploiting one-dimensional photonic crystal nanocavities, an ultra-compact indium phosphide-on-silicon laser diode with low current threshold, high wall-plug efficiency and high integrability is demonstrated. The most-awaited convergence of microelectronics and photonics promises to bring about a revolution for on-chip data communications and processing1. Among all the optoelectronic devices to be developed, power-efficient nanolaser diodes able to be integrated densely with silicon photonics and electronics are essential to convert electrical data into the optical domain. Here, we report a demonstration of ultracompact laser diodes based on one-dimensional (1D) photonic crystal (PhC) nanocavities2,3,4 made in InP nanoribs heterogeneously integrated on a silicon-waveguide circuitry. The specific nanorib design enables an efficient electrical injection of carriers in the nanocavity without spoiling its optical properties. Room-temperature continuous-wave (CW) single-mode operation is obtained with a low current threshold of 100 µA. Laser emission at 1.56 µm in the silicon waveguides is obtained with wall-plug efficiencies greater than 10%. This result opens up exciting avenues for constructing optical networks at the submillimetre scale for on-chip interconnects and signal processing.

In this extensive experimental study, the structural health monitoring (SHM) of a large 1 m × 1 m carbon fibre reinforced polymer laminate was performed using guided waves. Multiple hole- and crack-type defects were induced in the structure and the guided wave signals were collected using a circular network of piezoelectric disc transducers permanently bonded to the structure. Images representing each damage state of the composite plate were obtained by applying the (total focusing method, TFM with full matrix capture) on guided wave signals. Several variations in the image reconstruction algorithm were investigated by using two different baselines—pristine signals or signals collected during the last damage state-, processing only the positive amplitude by implementing a lower limit threshold and normalising the signals. The algorithms’ ability to detect and localise multiple defects, inside and outside the array, including holes as small as 2 mm in diameter, was evaluated. TFM images, involving the use of a lower threshold limit in the signal processing, resulted in more accurate detection. In addition, images obtained using both types of baseline provided complementary information leading to increased confidence in the system. All defects in the plate were detected and located even in the presence of multiple defects. Also, regions corresponding to crack- and hole-type of defects in the resulting images were identified, quantified and differentiated using geometric circularity and eccentricity shape factors. This ability of accurately identifying multiple defects and reducing location error are important contributions in the effort of establishing a reliable SHM system for multi-layered composite structures.

Rotating Radio Transients (RRATs) represent a relatively new class of pulsar, primarily characterised by their sporadic bursting emission of single pulses on time scales of minutes to hours. In addition to the difficulty involved in detecting these objects, low-frequency ( $ \lt 300\,\text{MHz}$ ) observations of RRATs are sparse, which makes understanding their broadband emission properties in the context of the normal pulsar population problematic. Here, we present the simultaneous detection of RRAT J2325−0530 using the Murchison Widefield Array (154 MHz) and Parkes radio telescope ( $1.4\,\text{GHz}$ ). On a single-pulse basis, we produce the first polarimetric profile of this pulsar, measure the spectral index ( $\alpha={-2.2\pm 0.1}$ ), pulse energy distributions, and present the pulse rates in the context of detections in previous epochs. We find that the distribution of time between subsequent pulses is consistent with a Poisson process and find no evidence of clustering over the $\sim\!1.5\,\text{h}$ observations. Finally, we are able to quantify the scintillation properties of RRAT J2325−0530 at 1.4 GHz, where the single pulses are modulated substantially across the observing bandwidth, and show that this characterisation is feasible even with irregular time sampling as a consequence of the sporadic emission behaviour.