Analysis & Synthesis of Distributed Control Systems with Sparse Interconnection Topologies

This dissertation is about control, identification, and analysis of systems with sparse interconnection topologies. We address two main research objectives relating to sparsity in control systems and networks. The first problem is optimal sparse controller synthesis, and the second one is the identification of sparse network. The first part of this dissertation starts with the chapter focusing on developing theoretical frameworks for the synthesis of optimal sparse output feedback controllers under pre-specified structural constraints. This is achieved by establishing a balance between the stability of the controller and the systems quadratic performance. Our approach is mainly based on converting the problem into rank constrained optimizations.We then propose a new approach in the syntheses of sparse controllers by em- ploying the concept of Hp approximations. Considering the trade-off between the controller sparsity and the performance deterioration due to the sparsification pro- cess, we propose solving methodologies in order to obtain robust sparse controllers when the system is subject to parametric uncertainties.Next, we pivot our attention to a less-studied notion of sparsity, namely row sparsity, in our optimal controller design. Combining the concepts from the majorization theory and our proposed rank constrained formulation, we propose an exact reformulation of the optimal state feedback controllers with strict row sparsity constraint, which can be sub-optimally solved by our proposed iterative optimization techniques. The second part of this dissertation focuses on developing a theoretical framework and algorithms to derive linear ordinary differential equation models of gene regulatory networks using literature curated data and micro-array data. We propose several algorithms to derive stable sparse network matrices. A thorough comparison of our algorithms with the existing methods are also presented by applying them to both synthetic and experimental data-sets

The Hepatoprotection Provided by Taurine and Glycine against Antineoplastic Drugs Induced Liver Injury in an Ex Vivo Model of Normothermic Recirculating Isolated Perfused Rat Liver

Taurine (2-aminoethane sulfonic acid) is a non-protein amino acid found in high concentration in different tissues. Glycine (Amino acetic acid) is the simplest amino acid incorporated in the structure of proteins. Several investigations indicate the hepatoprotective properties of these amino acids. On the other hand, antineoplastic agents-induced serum transaminase elevation and liver injury is a clinical complication. The current investigation was designed to screen the possible hepatoprotective properties of taurine and glycine against antineoplastic drugs-induced hepatic injury in an ex vivo model of isolated perfused rat liver. Rat liver was perfused with different concentration (10 µM, 100 µM and 1000 µM) of antineoplastic drugs (Mitoxantrone, Cyclophosphamide, Cisplatin, 5‑Fluorouracil, Doxorubicin and Dacarbazine) via portal vein. Taurine and glycine were administered to drug-treated livers and liver perfusate samples were collected for biochemical measurements (ALT, LDH, AST, and K+). Markers of oxidative stress (reactive oxygen species formation, lipid peroxidation, total antioxidant capacity and glutathione) were also assessed in liver tissue. Antineoplastic drugs caused significant pathological changes in perfusate biochemistry. Furthermore, markers of oxidative stress were significantly elevated in drug‑treated livers. It was found that taurine (5 and 10 mM) and glycine (5 and 10 mM) administration significantly mitigated the biomarkers of liver injury and attenuated drug‑induced oxidative stress. Our data indicate that taurine and glycine supplementation might help as potential therapeutic options to encounter anticancer drugs-induced liver injury.</p

Assimilation of Satellite-Derived Soil Moisture and Brightness Temperature in Land Surface Models: A Review

The correction of Soil Moisture (SM) estimates in Land Surface Models (LSMs) is considered essential for improving the performance of numerical weather forecasting and hydrologic models used in weather and climate studies. Along with surface screen-level variables, the satellite data, including Brightness Temperature (BT) from passive microwave sensors, and retrieved SM from active, passive, or combined active–passive sensor products have been used as two critical inputs in improvements of the LSM. The present study reviewed the current status in correcting LSM SM estimates, evaluating the results with in situ measurements. Based on findings from previous studies, a detailed analysis of related issues in the assimilation of SM in LSM, including bias correction of satellite data, applied LSMs and in situ observations, input data from various satellite sensors, sources of errors, calibration (both LSM and radiative transfer model), are discussed. Moreover, assimilation approaches are compared, and considerations for assimilation implementation are presented. A quantitative representation of results from the literature review, including ranges and variability of improvements in LSMs due to assimilation, are analyzed for both surface and root zone SM. A direction for future studies is then presented

Assimilation of Satellite-Derived Soil Moisture and Brightness Temperature in Land Surface Models: A Review

The correction of Soil Moisture (SM) estimates in Land Surface Models (LSMs) is considered essential for improving the performance of numerical weather forecasting and hydrologic models used in weather and climate studies. Along with surface screen-level variables, the satellite data, including Brightness Temperature (BT) from passive microwave sensors, and retrieved SM from active, passive, or combined active&ndash;passive sensor products have been used as two critical inputs in improvements of the LSM. The present study reviewed the current status in correcting LSM SM estimates, evaluating the results with in situ measurements. Based on findings from previous studies, a detailed analysis of related issues in the assimilation of SM in LSM, including bias correction of satellite data, applied LSMs and in situ observations, input data from various satellite sensors, sources of errors, calibration (both LSM and radiative transfer model), are discussed. Moreover, assimilation approaches are compared, and considerations for assimilation implementation are presented. A quantitative representation of results from the literature review, including ranges and variability of improvements in LSMs due to assimilation, are analyzed for both surface and root zone SM. A direction for future studies is then presented

Efficacy of combined virtual reality with constraint-induced movement therapy on upper limb function of children with hemiparetic cerebral palsy

Introduction: Hemiparetic cerebral palsy refers to an impairment caused by non-progressive damages to premature brain which is more sever in one side of the body than the other side. The aim of the present study was to determine the effects of combining constraint-induced movement therapy (CIMT) with virtual reality (VR) on upper limb functioning of children with hemiparetic cerebral palsy. Materials and Methods: In a single blind randomized, controlled trial, 16 children with hemiparetic cerebral palsy, who were selected through a simple random sampling method in Ahvaz city, were divided into 4 groups of CIMT, VR, CIMT+VR, and controls. Subjects in experimental groups participated in one-and-half-hour therapeutic sessions which were held every other day during a four-week period. Measures were conducted pre, post and 3-month after the treatment period using Pediatrics Motor Activity Log and Bruininks-Oseretsky Test of Motor proficiency (BOTMP). Sample randomization and statistical analysis of data through analysis of variance with repeated measures were conducted via SPSS-16 software in which alpha level was set at 0.05. Results: Data analysis for measurement tools was indicative of significant difference of combined group compared to VR, CIMT, and control groups (P < 0.01) (mean amounts of BOTMP, speed and dexterity changed from 0.15 ± 0.08 to 1.89 ± 0.33 in post-test). Data analysis for follow-up session revealed the retention of results for 4 groups (P = 0.32). Conclusion: Incorporating VR and CIMT may improve upper limb functioning of children with hemiparetic cerebral palsy through combining the advantages of both protocols and implementing them in an integrated program. Keywords: Constraint-induced movement therapy, Virtual reality, Upper limb function, Hemiparetic cerebral pals

Sulfasalazine-induced renal and hepatic injury in rats and the protective role of taurine

Introduction: Sulfasalazine is a drug commonly administrated against inflammatory-based disorders. On the other hand, kidney and liver injury are serious adverse events accompanied by sulfasalazine administration. No specific therapeutic option is available against this complication. The current investigation was designed to evaluate the potential protective effects of taurine against sulfasalazine-induced kidney and liver injury in rats. Methods: Male Sprague-Dawley rats were administered with sulfasalazine (600 mg/kg, oral) for 14 consecutive days. Animals received different doses of taurine (250, 500 and 1000 mg/kg, i.p.) every day. Markers of organ injury were evaluated on day 15th, 24 h after the last dose of sulfasalazine. Results: Sulfasalazine caused renal and hepatic injury as judged by an increase in serum level of creatinine (Cr), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP). The levels of reactive oxygen species (ROS) and lipid peroxidation were raised in kidney and liver of sulfasalazine-treated animals. Moreover, tissue glutathione reservoirs were depleted after sulfasalazine administration. Histopathological changes of kidney and liver also endorsed organ injury. Taurine administration (250, 500 and 1000 mg/kg/day, i.p) alleviated sulfasalazine-induced renal and hepatic damage. Conclusion: Taurine administration could serve as a potential protective agent with therapeutic capabilities against sulfasalazine adverse effects