Design, Control, and Optimization of Robots with Advanced Energy Regenerative Drive Systems

We investigate the control and optimization of robots with ultracapacitor based regenerative drive systems. A subset of the robot joints are conventional, in the sense that external power is used for actuation. Other joints are energetically self-contained passive systems that use ultracapacitors for energy storage. An electrical interconnection known as the star configuration is considered for the regenerative drives that allows for direct electric energy redistribution among joints, and enables higher energy utilization efficiencies. A semi-active virtual control strategy is used to achieve control objectives. We find closed-form expressions for the optimal robot and actuator parameters (link lengths, gear ratios, etc.) that maximize energy regeneration between any two times, given motion trajectories. In addition, we solve several trajectory optimization problems for maximizing energy regeneration that admit closed-form solutions, given system parameters. Optimal solutions are shown to be global and unique. In addition, closed-form expressions are provided for the maximum attainable energy. This theoretical maximum places limits on the amount of energy that can be recovered. Numerical examples are provided in each case to demonstrate the results. For problems that don\u27t admit analytical solutions, we formulate the general nonlinear optimal control problem, and solve it numerically, based on the direct collocation method. The optimization problem, its numerical solution and an experimental evaluation are demonstrated using a PUMA manipulator with custom regenerative drives. Power flows, stored regenerative energy and efficiency are evaluated. Experimental results show that when following optimal trajectories, a reduction of about 10-22% in energy consumption can be achieved. Furthermore, we present the design, control, and experimental evaluation of an energy regenerative powered transfemoral prosthesis. Our prosthesis prototype is comprised of a passive ankle, and an active regenerative knee joint. A novel varying impedance control approach controls the prosthesis in both the stance and swing phase of the gait cycle, while explicitly considering energy regeneration. Experimental evaluation is done with an amputee test subject walking at different speeds on a treadmill. The results validate the effectiveness of the control method. In addition, net energy regeneration is achieved while walking with near-natural gait across all speeds

Explaining women's employment under the Islamic state in Iran. Women, work and Islamism; ideology and resistance.

This study examines women's employment in Iran between 1979-1997, analysing the changing position of the Islamic state in reaction to economic circumstances and women's responses. In making this assessment the interaction between economic circumstances, the institutionalisation of gender inequality and also the responses of women are examined. This study demonstrates that economic forces and women's struggle for change undermined the Islamic state's gender relations. The Islamisation of state and society which followed the 1979 revolution involved an attempt by the Islamic state to seclude women within the home in accordance with the state's gender and employment policy and practices. The power of the state to transform gender relations, however, was constrained by the Iran - Iraq war, as the survival of many families depended on women's earnings. The end of the war with Iraq and the return of men to the workforce did not result in women's return to the home. Economic reconstruction and inflation increased women's participation in the workforce. This study demonstrates that in 1997, women's participation in the labour force, despite a rigid sexual division of labour imposed ideologically by the Islamic state is no less than it was in pre-1979. However, the state continued to strengthen patriarchal relationships within the home, employment and wider society, thus maintaining that women's participation in the workforce is by nature temporary and that ultimately a woman's place is in the home. Women of different classes and with different levels of religiosity responded to the economic circumstances and the state's gender ideology. Their participation in the political movements and their active role in the economy has raised gender consciousness. The result is an alliance between religious and secular women in urban areas who have demanded reforms and forced the Islamic state to return to the position of the reforms of pre-1979 in relation to women and the family, and women's education and employment

Clinical and Experimental Approach to the Benefits and Risks of Laser Treatment for Diabetic Macular Edema

Diabetic retinopathy is an ophthalmic complication of diabetes that currently affects 93 million people worldwide. Diabetic macular edema is a subtype of diabetic retinopathy that is characterized by leaking blood vessels in the central part of the retina, and it is a major cause of vision loss in individuals with diabetes. Screening for retinopathy is performed at regular intervals to identify subjects in need of treatment. In Sweden, the recommended screening interval for type 2 diabetic subjects with no diabetic retinopathy is 3 years. Laser treatment for diabetic macular edema has been used for decades, but studies have reported conflicting results regarding possible clinical complications following such therapy. Furthermore, the molecular events involved in the clinical benefits of laser treatment have not been fully explored. To determine the safety of the current screening interval, the 3-year incidence of diabetic retinopathy and macular edema was monitored in type 2 diabetic subjects with no retinopathy (Study I). To identify the long-term effects of laser treatment, the retinal sensitivity in 29 consecutively recruited subjects with diabetic macular edema was assessed by visual fields before and after laser treatment every 6 months during a period of 2 years (Study II). To investigate the cellular and molecular events that may be involved in the clinical benefits of laser treatment, a model of in vitro laser coagulation of the retinal pigment epithelium was established and used to evaluate cell death and cell repair (Study III). The same model was also used to explore the effects of laser treatment on mRNA and protein levels by analysis of microarray and proteomics data (Study IV). Study I demonstrated a very low incidence of sight-threatening diabetic retinopathy, which supports the current use of a 3-year retinal screening interval for the subgroup in question. Study II showed no change in retinal sensitivity following laser treatment for diabetic macular edema during the 2-year follow-up compared to baseline. Study III revealed that laser-induced damage involved both necrosis and apoptosis, and the repair process entailed both proliferation and migration. In study IV, the downregulation of the protein Carbonic anhydrase 9 and the upregulation of heat shock proteins 1A and 1B were the most interesting findings and might explain some of the beneficial effects of laser treatment for diabetic macular edema

A Review of the Application of Metal-Organic Frameworks in the Absorption, Storage and Release of Methane

Natural gas, which mainly consists of methane, is a good fuel for vehicles. Metal-organic frameworks (MOF) have attracted much attention as a new group of adsorbent materials in natural gas storage. MOF structures form various networks by connecting secondary structural units composed of metal ions and organic binders. These regular materials have high porosity and have high design capabilities. This feature has made MOFs suitable for special applications in trapping and absorbing various materials. The investigation of these materials has focused on the absorption of pure methane, although natural gas contains a small amount of larger hydrocarbons such as ethane and propane, which have greater absorption than methane. This Manuscript presents an overview of the current state of the metal-organic framework for methane storage

Analytical Solution of Biological Population of Fractional Differential Equations by Reconstruction of Variational Iteration Method

This article presents a brand-new approximation analytical technique we refer to as the reconstruction of variational iteration method. For the goal of solving fractional biological population option pricing equations, this methodology was created. In certain circumstances, you may actually use the well-known Mittag-Leffer function to get an explicit response. The usage of the three examples below demonstrates the precision and effectiveness of the suggested method. The results show that the RVIM is not only quite straightforward but also very successful at resolving non-linear problems

Solving the Optimal Trading Trajectory Problem Using a Quantum Annealer

We solve a multi-period portfolio optimization problem using D-Wave Systems' quantum annealer. We derive a formulation of the problem, discuss several possible integer encoding schemes, and present numerical examples that show high success rates. The formulation incorporates transaction costs (including permanent and temporary market impact), and, significantly, the solution does not require the inversion of a covariance matrix. The discrete multi-period portfolio optimization problem we solve is significantly harder than the continuous variable problem. We present insight into how results may be improved using suitable software enhancements, and why current quantum annealing technology limits the size of problem that can be successfully solved today. The formulation presented is specifically designed to be scalable, with the expectation that as quantum annealing technology improves, larger problems will be solvable using the same techniques.Comment: 7 pages; expanded and update

Review and prediction of trauma mortality

Quality management principles stipulate that outcome after injury is dependent upon patient factors, injury severity, structures and processes of care in a trauma system. Structures refers to the context in which care is delivered, including material resources, equipment and competence of involved personnel. Processes refers to what is literally done by the personnel involved in patient care. In this thesis, we examine the different aspects of this conceptual model with outcome as the main focus. Historically, trauma mortality has been the standard quality outcome measure. However, nontrauma related deaths and patients that are dead on arrival (DOA) in registries, complicates the interpretation of trauma mortality statistics. In Paper I, we demonstrated by clinical review of all deaths during 2007-2011 in a Level I trauma centre (Karolinska University Hospital – Solna [KUH]), that 30-day trauma mortality included 10.5% of non-trauma related deaths and the exclusion of DOAs significantly reduced the mortality rate. We concluded that review of all trauma deaths was necessary to correctly interpret trauma mortality. Analysis of preventable death (PD) is another quality outcome measure. The World Health Organization (WHO) has defined PD by the use of survival prediction models which calculates a probability of survival (Ps): non-PD with a Ps <25%, and potentially PD with a Ps >50%. In Paper II, we used a multidisciplinary peer review during 2012-2016, to identify the proportion of potentially PD and errors committed at KUH, and to evaluate the use of the WHO’s Ps cut-offs as a tool to identify the right patients to review, i.e., exclude non-PD from review or to focus review on potentially PD. We used the North American Trauma and Injury Severity Score (TRISS) and the Norwegian Survival Prediction Model in Trauma (NORMIT) to calculate the Ps. When applying the cut-off limits to the groups of non-PDs and potentially PDs for review, both models missed cases that otherwise needed to be reviewed. We concluded that peer review of all trauma deaths is essential in preventability analysis. Survival prediction models, which adjust for case-mix, have been developed to allow comparisons of the quality of trauma care between centres and over time. In Paper III, we used TRISS based risk-adjusted survival to compare two Scandinavian Level I trauma centres (KUH and Oslo University Hospital – Ullevål) during 2009-2011 and concluded that the model had its shortcomings when applied in a Scandinavian setting. The model lacks adjustments for age as a continuous variable and does not include comorbidity which, if included, could improve survival prediction in Scandinavian trauma populations. In Paper IV, we tested the accuracy of NORMIT and its later update (NORMIT 2), in regards to survival prediction, in two Swedish trauma populations; one national population including all hospitals admitting trauma patients in Sweden and one subpopulation of patients admitted to a single designated Level I trauma centre (KUH) during 2014-2016. We concluded that NORMIT 2 can be used to predict survival in a Swedish trauma centre population, but both NORMIT models performed poorly in a more heterogeneous national trauma population

Investigation of Emulsion Bitumen Adhesion to Aggregates in Chipseal at Various Temperatures for Low-Cost Pavement Management

Preventive maintenance is recommended by economic models in pavement management. One of the issues that the Chipseal mix is currently dealing with is the degree of separation of the material from the mixture's surface due to a lack of proper adhesion between the emulsion(green) bitumen, and the aggregate. Have and cause an accident. In this study, it was attempted to reduce material separation by increasing the percentage of bitumen in the mixture as well as the percentage of sand as a filler. The results of this study showed that with increasing the percentage of emulsion bitumen in the chipseal mixture and with it increases the percentage of filler in the mixture, the separation rate of aggregates to less than 10% in the temperature range of -15 to +45 ° C, and a Created a more cohesive mixture