Controlled one dimensional diffusions with switching costs—average cost criterion

AbstractThis paper deals with a one-dimensional controlled diffusion process on a compact interval with reflecting boundaries. The set of available actions is finite and the action can be changed only at countably many stopping times. The cost structure includes both a continuous movement cost rate depending on the state and the action, and a switching cost when the action is changed. The policies are evaluated with respect to the average cost criterion. The problem is solved by looking at, for each stationary policy, an embedded stochastic process corresponding to the state intervals visited in the sequence of switching times. The communicating classes of this process are classified into closed and transient groups and a method of calculating the average cost for the closed and transient classes is given. Also given are conditions to guarantee the optimality of a stationary policy. A Brownian motion control problem with quadratic cost is worked out in detail and the form of an optimal policy is established

Community based trial of home blood pressure monitoring with nurse-led telephone support in patients with stroke or transient ischaemic attack recently discharged from hospital.

BACKGROUND: High blood pressure in patients with stroke increases the risk of recurrence but management in the community is often inadequate. Home blood pressure monitoring may increase patients' involvement in their care, increase compliance, and reduce the need for patients to attend their General Practitioner if blood pressure is adequately controlled. However the value of home monitoring to improve blood pressure control is unclear. In particular its use has not been evaluated in stroke patients in whom neurological and cognitive ability may present unique challenges. DESIGN: Community based randomised trial with follow up after 12 months. PARTICIPANTS: 360 patients admitted to three South London Stroke units with stroke or transient ischaemic attack within the past 9 months will be recruited from the wards or outpatients and randomly allocated into two groups. All patients will be visited by the specialist nurse at home at baseline when she will measure their blood pressure and administer a questionnaire. These procedures will be repeated at 12 months follow up by another researcher blind as to whether the patient is in intervention or control group. INTERVENTION: INTERVENTION patients will be given a validated home blood pressure monitor and support from the specialist nurse. Control patients will continue with usual care (blood pressure monitoring by their practice). Main outcome measures in both groups after 12 months: 1. Change in systolic blood pressure.2. Cost effectiveness: Incremental cost of the intervention to the National Health Service and incremental cost per quality adjusted life year gained

Control of the Spanwise Distribution of Circulation on NACA 0012 and Flat Plate Wings

Open-loop active flow control is used to modify the spanwise distribution of circulation around an NACA 0012 and flat plate wing. The leading edge on both airfoils and tip regions of the NACA airfoil contain spatially localized actuators that can be independently controlled in terms of amplitude and frequency, allowing the spanwise distribution of circulation to be modified. Different orientations of the pulsed-blowing actuators were used to provide upstream, downstream, in-line with the flow, and outward span components of actuation. The actuation effectiveness was documented using force balance measurements of the lift and drag, smoke-wire visualization, surface pressure measurements and PIV velocity field measurements. Actuation with an upstream component is shown to be far more effective in reducing the separated region than actuation in the streamwise direction. Initial measurements of the change in circulation on the suction surface of the airfoil indicate that spatially localized forcing produces global changes over the wing, primarily associated with the reduction in size of the separated flow region

Control-Group Feature Normalization for Multivariate Pattern Analysis Using the Support Vector Machine

Normalization of feature vector values is a common practice in machine learning. Generally, each feature value is standardized to the unit hypercube or by normalizing to zero mean and unit variance. Classification decisions based on support vector machines (SVMs) or by other methods are sensitive to the specific normalization used on the features. In the context of multivariate pattern analysis using neuroimaging data, standardization effectively up- and down-weights features based on their individual variability. Since the standard approach uses the entire data set to guide the normalization it utilizes the total variability of these features. This total variation is inevitably dependent on the amount of marginal separation between groups. Thus, such a normalization may attenuate the separability of the data in high dimensional space. In this work we propose an alternate approach that uses an estimate of the control-group standard deviation to normalize features before training. We also show that control-based normalization provides better interpretation with respect to the estimated multivariate disease pattern and improves the classifier performance in many cases

A comparative study on drying of basil leaves

Basil is a popular aromatic and annual herb growing in many regions of the world.  Immediately after its harvesting, the highly perishable raw material, i.e. leaves, have to be preserved against deterioration and spoilage.  More often, during peak period, most of the crop is lost/wasted due to lack of proper post-harvest processing techniques.  Drying is by far the most widely used treatment, which needs to be performed very carefully and preciously so as to preserve the aroma and color of the leaves.  Various drying treatments and experimental methods viz., solar drying, tray drying, vacuum drying and fluidized bed drying were carried out at the temperatures of45°C,55°Cand65°Cto find and suggest the optimum drying condition for acquiring quality dried basil leaves.  Results have revealed that ‘total drying time’ is considerably reduced with the increase in drying air temperatures from45°Cto65°C.  It could be recommended that for the best drying of basil leaves, the drying operation needs to be carried out in the fluidized bed dryer at 45ºC for 30 s steam blanched sample ensuring the best results in quality of basil leaves as compared to other methods and treatments whatever considered during present study

Addressing Confounding in Predictive Models with an Application to Neuroimaging

Understanding structural changes in the brain that are caused by a particular disease is a major goal of neuroimaging research. Multivariate pattern analysis (MVPA) comprises a collection of tools that can be used to understand complex disease effects across the brain. We discuss several important issues that must be considered when analyzing data from neuroimaging studies using MVPA. In particular, we focus on the consequences of confounding by non-imaging variables such as age and sex on the results of MVPA. After reviewing current practice to address confounding in neuroimaging studies, we propose an alternative approach based on inverse probability weighting. Although the proposed method is motivated by neuroimaging applications, it is broadly applicable to many problems in machine learning and predictive modeling. We demonstrate the advantages of our approach on simulated and real data examples

Optimization of cogging torque in interior permanent magnet synchronous motor using optimum magnet v-angle

Introduction. At present, the most important requirement in the field of electrical engineering is the better utilization of electrical power, due to its increasing demand and not-so-increasing availability. A permanent magnet synchronous motor (PMSM) is increasingly gaining popularity in various household and industrial applications because of its superior performance compared to conventional electrical motors. Purpose. PMSM is designed based on the selection of various design variables and optimized to fulfill the same. Being superiorly advantageous over other motors, PMSM has the major disadvantage of higher cogging torque. Higher cogging torque generates torque ripple in the PMSM motor leading to various problems like vibration, rotor stress, and noisy operation during starting and steady state. The designer should aim to reduce the cogging torque at the design stage itself for overall better performance. Methods. An interior rotor v-shaped web-type PMSM is designed and its performance analysis is carried out using finite element analysis (FEA). Magnet v-angle is optimized with the objective of cogging torque reduction. Performance comparison is carried out between the optimized motor and the initially designed motor with FEA. Novelty. Magnet v-angle analysis is performed on the same keeping all other parameters constant, to obtain minimum cogging torque. The proposed method is practically viable as it does not incur extra costs and manufacturing complexity. Practical value. It is observed that the magnet v-angle is an effective technique in the reduction of cogging torque. Cogging torque is reduced from 0.554 N×m to 0.452 N×m with the application of the magnet v-angle optimization technique.Вступ. В даний час найважливішою вимогою в галузі електротехніки є найкраще використання електроенергії через зростаючу потребу в ній і не настільки зростаючу доступність. Синхронний двигун з постійними магнітами (СДПМ) набуває все більшої популярності в різних побутових та промислових застосуваннях завдяки своїм чудовим характеристикам у порівнянні зі звичайними електродвигунами. Мета. СДПМ, спроєктований на основі вибору різних конструктивних змінних та оптимізований для їх виконання. Будучи чудовим у порівнянні з іншими двигунами, СДПМ має головний недолік: вищий крутний момент. Вищий крутний момент викликає пульсації крутного моменту в двигуні з постійними магнітами, що призводить до різних проблем, таких як вібрація, напруга ротора і шумна робота під час запуску і режиму. Проєктувальник повинен прагнути зменшити крутний момент зубчастого колеса на стадії проєктування для підвищення загальної продуктивності. Методи. Розроблено СДПМ з внутрішнім ротором v-подібної форми та стрижневого типу, та аналіз його характеристик виконаний з використанням аналізу методом скінченних елементів (FEA). Кут v-подібного магніту оптимізовано з метою зниження зубчастого моменту. Порівняння продуктивності здійснюється між оптимізованим двигуном та двигуном, спочатку спроєктованим за допомогою FEA. Новизна. Аналіз кута v-подібного магніту виконується таким же чином, зберігаючи решту всіх параметрів постійними, щоб отримати мінімальний зубчастий крутний момент. Запропонований спосіб практично життєздатний, оскільки не вимагає додаткових витрат та складності виготовлення. Практична цінність. Помічено, що v-подібний кут магніту є ефективним способом зниження зубчастого моменту. Зубчастий крутний момент зменшений з 0,554 Н×м до 0,452 Н×м за рахунок застосування методу оптимізації v-подібного кута магніту

Dense Motion Estimation for Smoke

Motion estimation for highly dynamic phenomena such as smoke is an open challenge for Computer Vision. Traditional dense motion estimation algorithms have difficulties with non-rigid and large motions, both of which are frequently observed in smoke motion. We propose an algorithm for dense motion estimation of smoke. Our algorithm is robust, fast, and has better performance over different types of smoke compared to other dense motion estimation algorithms, including state of the art and neural network approaches. The key to our contribution is to use skeletal flow, without explicit point matching, to provide a sparse flow. This sparse flow is upgraded to a dense flow. In this paper we describe our algorithm in greater detail, and provide experimental evidence to support our claims.Comment: ACCV201

Combining interpolation and 3D level set method (I+3DLSM) for medical image segmentation

A combined interpolation - 3D Level Set Method (I+3DLSM) based segmentation process is presented. The performance in terms of accuracy of the 3-dimensional (3D) level set method (LSM) in the segmentation of throat regions from highly anisotropic magnetic resonance imaging (MRI) volumes, with and without an interpolation step is evaluated. Qualitative and quantitative results from real MRI data suggest that performing interpolation, to reconstruct isotropic MRI volumes, prior to 3D LSM improves the accuracy of the segmentation results, compared to interpolation post 3D LSM and no interpolation at all

Microengineered cathode interface studies

The overpotential at the cathode/electrolyte interface has been recognized as an important limitation on the performance of solid oxide fuel cells (SOFCs). This project is an effort to gain a scientific understanding of which interface features and conditions contribute to cathode polarization in SOFCs. The paper discusses three possible rate-limiting factors in the cathode reaction. The paper studies the electronic conductivity in the electrolyte, the ionic conductivity in the cathode, cathode geometry near the interface, and cathode surface area