Consistent Approximations for the Optimal Control of Constrained Switched Systems

Though switched dynamical systems have shown great utility in modeling a variety of physical phenomena, the construction of an optimal control of such systems has proven difficult since it demands some type of optimal mode scheduling. In this paper, we devise an algorithm for the computation of an optimal control of constrained nonlinear switched dynamical systems. The control parameter for such systems include a continuous-valued input and discrete-valued input, where the latter corresponds to the mode of the switched system that is active at a particular instance in time. Our approach, which we prove converges to local minimizers of the constrained optimal control problem, first relaxes the discrete-valued input, then performs traditional optimal control, and then projects the constructed relaxed discrete-valued input back to a pure discrete-valued input by employing an extension to the classical Chattering Lemma that we prove. We extend this algorithm by formulating a computationally implementable algorithm which works by discretizing the time interval over which the switched dynamical system is defined. Importantly, we prove that this implementable algorithm constructs a sequence of points by recursive application that converge to the local minimizers of the original constrained optimal control problem. Four simulation experiments are included to validate the theoretical developments

Empowering girls, delaying marriage: Exploring the role of marital age and education on domestic violence in India

Domestic violence represents the most important component of violence against women. Whilst some literature report female empowerment as a protective factor against domestic violence, some literature find the opposite because the husband may attempt to compensate for the enhanced status of his wife. This paper aims to investigate the effects of female empowerment in the form of marital age and education on domestic violence in India, where intimate partner violence is amongst the highest in Asia. The analysis is based on the sample of eligible women aged 15-49 with valid response on domestic violence in the 2015- 2016 National Family Health Survey (NFHS-4) (n=9722). Upon estimating a series of instrumental variable (IV) regressions using age at menarche as an exogenous and strong instrument, we establish a causal relationship between empowerment and domestic violence taking into account the endogeneity of marital age and education. We further disentangle the relationships between domestic violence and age at marriage and education, separately. In addition, we investigate how maritage age and education influence domestic violence through labour market participation and spouse quality channels. We find that: i) empowered women do experience less domestic violence; ii) marital age and education are partially complementary; iii) labour market participation and spousal quality are relevant mediators of these relationships. Policies aiming at reducing domestic violence in India hence should be holistic, focussing on investing in education both for women and men and improving the conditions of the women’ labour market

DoA estimation in EM lens assisted massive antenna system using subsets based antenna selection and high resolution algorithms

In recent times, massive antenna array technology has captured significant attention among wireless communication researchers. This is a field with strong potential to increase rates of data transfer; mitigate interference and serve a large number of users simultaneously. To contribute further to this emerging technology, this paper presents an approach for the line-of-sight (LoS) based direction of arrival (DoA) estimation using the electromagnetic (EM) lens-focusing antenna concept. The EM lens focuses the received signal energy as a function of the angle of arrival (AoA) to a small subset/area of the antenna array. This is advantageous, as it helps to reduce both hardware implementation (RF chains) and the complexity of signal processing in the large number of antennas system. Furthermore, this focusing capability of the EM lens provides additional interference rejection gain which leads to estimate the DoA of user terminals precisely. Hence, in this work, subsets based antenna selection approach and subspace-based high resolution DoA estimation algorithms have been considered in combination with the EM lens assisted massive antenna system. In simulations where the DoA is estimated with the EM lens, the results are comparable with conventional methods of DoA estimation without an EM lens, despite the significantly reduced overall system complexity

Performance analysis of 180\ub0 HRR coupler used for direction finding with an antenna array

This paper presents the performance analysis of  hybrid rat race coupler, widely used in radio frequency (RF)/wireless communication systems to couple the power in the desired way. The  hybrid ring coupler consists of 4 ports, two for the input signals and two for the output signals, where sum and difference patterns of the applied two signals can be obtained at two output ports and usually called sum and difference ports. In this work, the couplers have been designed and simulated at central frequencies (fo) of 2.4 and 10 GHz using different types of substrates such as RT Duroid 5880 and FR4.  Furthermore, the coupler has been used for direction finding (angle-of-arrival estimation) application, where we combine the designed  hybrid rat race coupler with a simple two antenna elements array  (at fo=10GHz and RT Duroid =2.2) and fabricate the circuit in order to validate the performance of the coupler by measuring the direction of arrival (DoA) from  and  ports. The obtained results show that good performance can be achieved with the designs considered in this paper.

An Improved Algorithm to Solve Transportation Problems for Optimal Solution

In this paper, we have developed an algorithm to obtain initial basic feasible solution of transportation problems where the object is to minimize the transportation cost. The proposed method is compared with well-known existing methods including Least-Cost Method and North-West Corner Method and is found to yield better results. Feasible solution from the proposed method leads to solution closest to the optimal solution; and in some numerical examples same as the optimal solution. Key words: Transportation problem, Initial Basic Feasible Solution, Optimal Solutio

Optimization of Process Parameters for CNC Turning using Taguchi Methods for EN24 Alloy Steel with Coated/Uncoated Tool Inserts

Coated and uncoated tool inserts offers certain degrees of control on the desired rate of tool wear and surface roughness to an extent. This work pursues the quest for realizing the optimal values for the significant process parameters that bears an influence on the response parameters. Experiments were conducted on the samples of EN 24 alloy steel material with the help of PVD coated TiAlN insert and uncoated carbide insert. The experimental runs carried out with proper variation in the levels. Levels are selected with the help of manufacturing catalogue and by pilot experimentation and results are recorded for further analysis. For this study, 9 runs designed using L9 orthogonal array of Taguchi Design of Experiment. Surface roughness was measured using a Mitutoyo surface tester at test lab and material removal rate is calculated by mathematical equation. The data was compiled into Minitab 17 software for analysis. The relationship between the machining parameters and the response variables were analyzed using the Taguchi Method. Optimization of process parameters is carried out by Grey Relational Analysis method (GRA). GRA method is a powerful and most versatile tool which can manipulate the input data as per requirement and comes with results that can be used to have best multi-objective in respective concerns

Diphenhydramine-dependence Resulting From Self-medication of Antipsychotic- induced Extrapyramidal Symptoms

Antipsychotic-induced extrapyramidal symptoms should be recognised and adequately treated. We report an unusual complication of not doing so: a patient’s self-medicating to control these symptoms, which produced diphenhydramine-dependence

Flow induced vibration of a square cylinder with high scruton number

Flow over a square cylinder is numerically studied to understand the effect of reduced velocity to the transverse oscillation under the influence of high Scruton number elastic system of 4.316. For low reduced velocities, the transverse oscillation behavior can be grouped in the initial branch region. In this region, the motion is mainly controlled by the lift fluctuation. For intermediate reduced velocities, the transverse oscillation behavior is grouped in the lower branch region. In this region, its natural frequency slowly becomes significant. For high reduced velocities, the galloping region is observed. In this region, the natural frequency dominated the shape of the amplitude oscillation

Outcome of adult patients with acute lymphoblastic leukaemia receiving the MRC UKALL XII protocol: a tertiary care centre experience

Introduction:Acute lymphoblastic leukaemia (ALL) is a heterogeneous group of lymphoid neoplasm resulting from the proliferation of malignant lymphoid cells. We aimed to study the outcome of adult Patients with ALL receiving the Medical Research Council UKALL XII protocol. Methods: This was a retrospective study conducted at Aga Khan University Hospital from January 2001 to December 2008. The medical records of all adult Patients were reviewed and analysed for clinical, morphological and immunological features at presentation and impact on treatment outcomes. Multivariate analysis and survival studies were performed using Kaplan-Meier statistics. Results: The total number of Patients was 54, with a male to female ratio of 3.4:1 and a median age of 28 years. Common presenting symptoms were fever (n is 49) and bleeding (n is 14). 38 Patients had haemoglobin less than 10 gms/dl, 21 had white blood cell (WBC) count of 50 x 10E9/L or more, and 35 had lactate dehyrogenase more than 1,000 IU. Morphologically, FAB-L2 was the commonest subtype, with 38 Patients with B-ALL and eight with T-ALL. Multivariate analysis showed that age above 30 years, male gender, WBC count above 50 x 10E9/L and T-ALL subtype were independent risk factors for poor survival. 46 (85 percent) Patients achieved complete remission. The median survival was 12.3 months. At the end of five years, 16 Patients were alive, two were alive with disease and 14 were in complete remission. Conclusion: Overall survival and relapse rates in our study were comparable to those reported internationally