PI-in-a-box: Intelligent onboard assistance for spaceborne experiments in vestibular physiology

In construction is a knowledge-based system that will aid astronauts in the performance of vestibular experiments in two ways: it will provide real-time monitoring and control of signals and it will optimize the quality of the data obtained, by helping the mission specialists and payload specialists make decisions that are normally the province of a principal investigator, hence the name PI-in-a-box. An important and desirable side-effect of this tool will be to make the astronauts more productive and better integrated members of the scientific team. The vestibular experiments are planned by Prof. Larry Young of MIT, whose team has already performed similar experiments in Spacelab missions SL-1 and D-1, and has experiments planned for SLS-1 and SLS-2. The knowledge-based system development work, performed in collaboration with MIT, Stanford University, and the NASA-Ames Research Center, addresses six major related functions: (1) signal quality monitoring; (2) fault diagnosis; (3) signal analysis; (4) interesting-case detection; (5) experiment replanning; and (6) integration of all of these functions within a real-time data acquisition environment. Initial prototyping work has been done in functions (1) through (4)

Imaging in prostate cancer today and tomorrow: radiology

Za oceno karcinomov v prostati in lokalno zamejitev se v vsakdanji praksi uporablja multiparametrična magnetnoresonančna preiskava (mp MR), standardizirana po sistemu PI-RADS 2.1 (angl. Prostate Imaging Reporting and Data System). Za opredelitev kategorije PI-RADS 2.1 se uporabljajo T2-obtežene sekvence, difuzijsko obtežene sekvence ter dinamično kontrastno ojačane slike. Magnetnoresonančna preiskava je primerna za odkrivanje malignomov, lokalizacijo sprememb, kot vodilo za biopsijo in zamejitev bolezni. Z naraščajočim številom mp MR-preiskav prostate so se pokazale nove težave in številna vprašanja, ki zahtevajo razmišljujočega, v prihodnost usmerjenega radiologa. Ne glede na kakovost in izkušenost radiologa, ki se ukvarja z diagnostiko raka prostate, je do 20 % klinično pomembnih rakov »spregledanih« oz. opredeljenih kot klinično nepomembnih. Po drugi strani pa je zaradi benigne patologije veliko sprememb v prostati opredeljenih kot lažno pozitivnih. Z novimi pristopi, kot so radiomika, spremembe pri klasifikaciji ter uvedba novih pristopov, bo v prihodnosti MR-preiskava prostate postala še uspešnejše orodje za diagnostiko in spremljanje bolnikov z rakom prostate

Enhancing Time Series Aggregation For Power System Optimization Models: Incorporating Network and Ramping Constraints

Power system optimization models are large mathematical models used by researchers and policymakers that pose tractability issues when representing real-world systems. Several aggregation techniques have been proposed to address these computational challenges and it remains a relevant topic in power systems research. In this paper, we extend a recently developed Basis-Oriented time series aggregation approach used for power system optimization models that aggregates time steps within their Simplex basis. This has proven to be an exact aggregation for simple economic dispatch problems. We extend this methodology to include network and ramping constraints; for the latter (and to handle temporal linking), we develop a heuristic algorithm that finds an exact partition of the input data, which is then aggregated. Our numerical results, for a simple 3-Bus system, indicate that: with network constraints only, we can achieve a computational reduction by a factor of 1747 (measured in the number of variables of the optimization model), and of 12 with ramping constraints. Moreover, our findings indicate that with temporal linking constraints, aggregations of variable length must be employed to obtain an exact result (the same objective function value in the aggregated model) while maintaining the computational tractability, this implies that the duration of the aggregations does not necessarily correspond to commonly used lengths like days or weeks. Finally, our results support previous research concerning the importance of extreme periods on model results.Comment: 10 pages, 5 figures, journal pre-prin

Model reduction for dynamic sensor steering : a Bayesian approach to inverse problems

Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 97-101).In many settings, distributed sensors provide dynamic measurements over a specified time horizon that can be used to reconstruct information such as parameters, states or initial conditions. This estimation task can be posed formally as an inverse problem: given a model and a set of measurements, estimate the parameters of interest. We consider the specific problem of computing in real-time the prediction of a contamination event, based on measurements obtained by mobile sensors. The spread of the contamination is modeled by the convection diffusion equation. A Bayesian approach to the inverse problem yields an estimate of the probability density function of the initial contaminant concentration, which can then be propagated through the forward model to determine the predicted contaminant field at some future time and its associated uncertainty distribution. Sensor steering is effected by formulating and solving an optimization problem that seeks the sensor locations that minimize the uncertainty in this prediction. An important aspect of this Dynamic Sensor Steering Algorithm is the ability to execute in real-time. We achieve this through reduced-order modeling, which (for our two-dimensional examples) yields models that can be solved two orders of magnitude faster than the original system, but only incur average relative errors of magnitude O(10-3). The methodology is demonstrated on the contaminant transport problem, but is applicable to a broad class of problems where we wish to observe certain phenomena whose location or features are not known a priori.by Sonja Wogrin.S.M

El control estadístico de la calidad en la técnica del hormigón

Not availableSe acostumbra evaluar según las leyes de la estadística matemática los resultados de investigaciones relacionadas entre sí y expresarlos mediante valores característicos que permitan clasificar determinadas propiedades de las muestras tomadas al azar. La conclusión que se obtiene se refiere a la totalidad y se consigue así una imagen del estado del material que hay que enjuiciar

Professional caregivers: stress and coping in the face of loss and trauma

Professional caregivers who work with the trauma and suffering of others, such as doctors, nurses and psychologists, may face significant challenges along with the risk of adverse, long-term mental and physical health problems. Caregivers with responsibility for dependants outside their professional work reported more stress. This finding is of particular relevance in respect of caregivers in underdeveloped countries such as Zimbabwe, where many households have taken in additional children who have been orphaned, whose parents are ill, or whose parents have temporarily gone elsewhere in search of work. For the purposes of the study, a qualitative phenomenological research design was selected as appropriate to the focus on human experience. An interpretative approach was adopted to explore and explicate the lived experiences of the participants and the meaning they attached to them. The major sources of stress for professional caregivers emerged as being resource constraints, interpersonal issues, and personal issues. Factors found to promote coping include the caregiver’s meaning making perspective, making a difference, and constructing a sense of personal control

Towards resilient energy communities : evaluating the impact of economic and technical optimization

This paper assesses the difference of optimal operation of energy communities (ECs) with respect to economic and technical goals. ECs have emerged as a promising solution for accelerating the transition to more sustainable energy systems and therefore climate change mitigation. While cost optimization (economic goal) is most commonly used in ECs, optimizing their resilience (technical goal) can be an important part of operating a distribution grid with high photovoltaic (PV) and electrical vehicle (EV) penetration in the future. This paper presents a comparative analysis of the impact of those two objective functions on overall EC costs as well as individual member costs. The findings highlight the trade-off between the flexibility measures required for a resilient EC and the cost associated with them. This study helps quantify the subsidies that would be required to incentives EC to operate in a resilient matter as a form of grid service