Complete Subdivision Algorithms, II: Isotopic Meshing of Singular Algebraic Curves

Given a real valued function f(X,Y), a box region B_0 in R^2 and a positive epsilon, we want to compute an epsilon-isotopic polygonal approximation to the restriction of the curve S=f^{-1}(0)={p in R^2: f(p)=0} to B_0. We focus on subdivision algorithms because of their adaptive complexity and ease of implementation. Plantinga and Vegter gave a numerical subdivision algorithm that is exact when the curve S is bounded and non-singular. They used a computational model that relied only on function evaluation and interval arithmetic. We generalize their algorithm to any bounded (but possibly non-simply connected) region that does not contain singularities of S. With this generalization as a subroutine, we provide a method to detect isolated algebraic singularities and their branching degree. This appears to be the first complete purely numerical method to compute isotopic approximations of algebraic curves with isolated singularities

I. PHOTOTITRIMETRIC DETERMINATION OF SULFHYDRYL COMPOUNDS WITH O-HYDROXYMERCURIBENZOIC ACID USING DITHIOFLUORESCEIN AS AN INDICATOR. II. PURIFICATION AND PARTIAL CHARACTERIZATION OF CYSTEINE-GLUTAMATE TRANSAMINASE FROM RAT LIVER.

Source: Dissertation Abstracts International, Volume: 38-04, Section: B, page: 1691. Thesis (Ph.D.)--University of Windsor (Canada), 1977

Analyzing the Impact of Covid-19 Control Policies on Campus Occupancy and Mobility via Passive WiFi Sensing

Mobile sensing has played a key role in providing digital solutions to aid with COVID-19 containment policies. These solutions include, among other efforts, enforcing social distancing and monitoring crowd movements in indoor spaces. However, such solutions may not be effective without mass adoption. As more and more countries reopen from lockdowns, there remains a pressing need to minimize crowd movements and interactions, particularly in enclosed spaces. This paper conjectures that analyzing user occupancy and mobility via deployed WiFi infrastructure can help institutions monitor and maintain safety compliance according to the public health guidelines. Using smartphones as a proxy for user location, our analysis demonstrates how coarse-grained WiFi data can sufficiently reflect indoor occupancy spectrum when different COVID-19 policies were enacted. Our work analyzes staff and students' mobility data from three different university campuses. Two of these campuses are in Singapore, and the third is in the Northeastern United States. Our results show that online learning, split-team, and other space management policies effectively lower occupancy. However, they do not change the mobility for individuals transitioning between spaces. We demonstrate how this data source can be put to practical application for institutional crowd control and discuss the implications of our findings for policy-making.Comment: 25 pages, 18 figure

An end-to-end framework for real-time automatic sleep stage classification.

Sleep staging is a fundamental but time consuming process in any sleep laboratory. To greatly speed up sleep staging without compromising accuracy, we developed a novel framework for performing real-time automatic sleep stage classification. The client-server architecture adopted here provides an end-to-end solution for anonymizing and efficiently transporting polysomnography data from the client to the server and for receiving sleep stages in an interoperable fashion. The framework intelligently partitions the sleep staging task between the client and server in a way that multiple low-end clients can work with one server, and can be deployed both locally as well as over the cloud. The framework was tested on four datasets comprising ≈1700 polysomnography records (≈12000 hr of recordings) collected from adolescents, young, and old adults, involving healthy persons as well as those with medical conditions. We used two independent validation datasets: one comprising patients from a sleep disorders clinic and the other incorporating patients with Parkinson's disease. Using this system, an entire night's sleep was staged with an accuracy on par with expert human scorers but much faster (≈5 s compared with 30-60 min). To illustrate the utility of such real-time sleep staging, we used it to facilitate the automatic delivery of acoustic stimuli at targeted phase of slow-sleep oscillations to enhance slow-wave sleep

National Culture and the Preference for Management Controls: An exploratory Study of the Firm- Labor Market Interface

Abstract This study uses Hofstede's taxonomy of work-related national cultural dimensions to analyze preferences for specific management controls at the interface between the organization and the external labor market. Four experiments were conducted with samples of last-semester Japanese and U.S. MBA students. Most of the results did not provide support for the four hypotheses. These findings used as the basis for suggesting potential directions for future empirical refinements and theory construction

The Effects of Management Controls and National Culture on Manufacturing Performance: an Experimental Investigation

The increasing dominance of Asian manufacturing firms in the global economy has raised an important issue: whether these firms' superior manufacturing performance is caused by their management control systems, the national culture of their employees, or the interaction of these two factors. This experimental study provides a direct test of the effects of national culture and management control system on manufacturing performance. The dimension of national culture studied was individualism ( vs collectivism )because this work-related attribute has been noted as a major difference between Asian and Western cultures. In turn, the focus on cultural individualism motivated a study of two aspects of management controls: work flow interdependence and pay interdependence. The results are consistent with cultural individualism and management controls having independent, but not interactive, effects on manufacturing performance. The potential implications of these findings and suggestions for future research are discussed

Separate and overlapping brain areas encode subjective value during delay and effort discounting

AbstractMaking decisions about rewards that involve delay or effort requires the integration of value and cost information. The brain areas recruited in this integration have been well characterized for delay discounting. However only a few studies have investigated how effort costs are integrated into value signals to eventually determine choice. In contrast to previous studies that have evaluated fMRI signals related to physical effort, we used a task that focused on cognitive effort. Participants discounted the value of delayed and effortful rewards. The value of cognitively effortful rewards was represented in the anterior portion of the inferior frontal gyrus and dorsolateral prefrontal cortex. Additionally, the value of the chosen option was encoded in the anterior cingulate cortex, caudate, and cerebellum. While most brain regions showed no significant dissociation between effort discounting and delay discounting, the ACC was significantly more activated in effort compared to delay discounting tasks. Finally, overlapping regions within the right orbitofrontal cortex and lateral temporal and parietal cortices encoded the value of the chosen option during both delay and effort discounting tasks. These results indicate that encoding of rewards discounted by cognitive effort and delay involves partially dissociable brain areas, but a common representation of chosen value is present in the orbitofrontal, temporal and parietal cortices