Particle swarm optimization: theoretical analysis, modifications, and applications to constrained optimization problems

This is a PhD thesis by publication. It includes five journal papers, three of them already published, and two submitted for publication in a very high quality international journal in the field of Evolutionary Computation (one of which – as an invited paper). Further, the thesis contains also four conference papers presented and published in the top peer reviewed conferences, as well as one peer reviewed chapter book. In this thesis we studied an optimization algorithm called Particle Swarm Optimization (PSO) from theoretical and application point of views. The main focus of the theoretical analysis of the algorithm was towards understanding and addressing its limitations that were related to transformations of the search space, convergence to quality solutions, and stability. Through analysis of the algorithm under transformations of the search space we proposed a modification to the original PSO so that a stable performance was guaranteed when the search space was transformed, i.e., rotated, scaled, and translated. We also studied the ability of the original PSO in locating optimum solutions (local and global optima). Our study showed that this algorithm cannot guarantee to find a local optimum. We introduced a general formulation of topology for the original PSO and identified conditions so that it did not only guarantee local convergence but also transformation invariance. Further, we proposed a specific formulation, extracted from the general formulation, and experimentally confirmed the theoretical findings. We investigated the most recent standard version of SPSO, called standard PSO 2011 (SPSO2011), from stability, convergence, and transformation sensitivity perspectives. Our investigations revealed essential differences between stability conditions for SPSO2011 with earlier PSO variants. We introduced stability conditions for SPSO2011 and analyzed the behavior of the algorithm before collapsing on its equilibrium. Also, we proved that this algorithm cannot guarantee to find a local optimum in the search space. We introduced sufficient condition for a general formulation that represents a large class of PSO variants so that convergence to a local optimum is guaranteed. We then modified SPSO2011 so that the mentioned sufficient condition was satisfied and convergence to local optimum was guaranteed. Apart from theoretical analysis, we also studied performance of the algorithm when it was applied to continuous space constrained optimization problems (COPs). We introduced a new aspect in dealing with constrained optimization problems namely locating disjoint feasible regions in a search space. We developed a variant of PSO that was able to locate disjoint feasible regions in a search space. This track of research can potentially be of interest of many other researchers in the field of optimization in future. As it has been emphasized in many articles, the boundaries of feasible and infeasible regions in a COP can lead optimization algorithms to high quality solutions. We introduced a new approach to concentrate the search on the boundaries of the feasible and infeasible space. As a case study we used a variant of PSO and we confirmed that the results of the new approach are competitive with that of existing approaches in dealing with constraints. We also proposed a coding scheme to map a discrete space constrained optimization problem, namely multi-dimensional knapsack problem, to a continuous space constrained optimization problem. Then, we investigated the ability of a variant of PSO to deal with the mapped version of this problem.Thesis (Ph.D.) -- University of Adelaide, School of Computer Science, 201

Evaluation of IFN-gamma and HSP70 level in the saliva of Behcet’s disease patients with active oral lesions

Introduction:\ua0Behcet’s disease (BD) is a multi-systemic inflammatory disorder. Evaluating the production of cytokines such as interferon gamma and biomarkers such as heat shock protein-70 (HSP70)is an important way to study the pathogenesis and development of BD. This study aimed to compare the salivary level of interferon gamma and HSP70 between patients infected with BD and healthy individual.Methods:\ua0This case-control study was performed on 35 patients with Behcet’s syndrome and 70 healthy individuals as the control group, who were selected from those referring to the Department of Oral Medicine of Tabriz University of Medical Sciences. The levels of interferon gamma and HSP70 were measured in the whole unstimulated saliva through enzyme-linked immunosorbent assay (ELIZA). In order to compare the quantitative variables between two groups, independent samples t-test or its nonparametric equivalent, Mann-Whitney U test, was used in SPSS software version 16.0. In this study, a\ua0P\ua0value less than 0.05 was considered statistically significant.Results:\ua0There was no significant difference between the study groups in terms of age and gender, as well as salivary interferon gamma and HSP70 levels. Interferon gamma level was 15.16±3.38 pg/mg in the case group and 5.27±1.21 pg/mg in the control group, and salivary HSP70 level was found to be 45.50±17 ng/mL and 19.5±5.2 ng/mL in the case and control groups, respectively.Conclusions:\ua0The results of this study showed that interferon gamma and HSP70 levels in patients with Behcet’s syndrome are high and can be evaluated as an important tool for the treatment and evaluation of disease development in future studies

EFFECTS OF AGE INCREMENT AND 36-WEEK EXERCISE TRAINING ON ANTIOXIDANT ENZYMES AND APOPTOSIS IN RAT HEART TISSUE

This study investigated the onset of age-related changes in the myocardial antioxidant enzymes and apoptosis and the vulnerability of the myocardium to oxidative stress following exercise training. Few studies have investigated the influence of the most prevalent life-prolonging strategy physical exercise, on the age increment alterations in the myocardial antioxidant enzymes and apoptosis at mid age and to determine whether exercise-induced antioxidant defense system could attenuate lipid peroxidation. Thirty six male Wistar rats were randomly assigned to exercise trained (n = 18) and sedentary (n = 18) groups. The rats in the training group went under 12, 24 and 36 weeks of moderate exercise trainings (25 m·min-1 for 60-min with a 0% slope). Six sedentary controls were killed together with each exercise group at the end of the training programs. Levels of thiobarbituric acid-reactive substances (TBARS) and catalase (CAT) activity in myocardial homogenates were unchanged by training irrespective of the protocol duration. However, an increased content of the TBARS was detected in hearts from both the 24 and 36-week trained and sedentary control rats when compared with their corresponding 12-week groups (p<0.01). The activity of superoxide dismutase (SOD) remained unchanged after the 12-week training period whereas a significant increase was observed in heart homogenates of 24-week trained animals as compared with their sedentary controls (p<0.05). The activity of glutathione peroxidase (GPX) remained unchanged. The rates of apoptosis which was detected by ELISA assays, were significantly modified after 24 and 36-week of training (p<0.05). These results demonstrate that a long-term endurance training (24 weeks) induced increases in SOD activities in rat myocardium and elicited a marked reduction in apoptosis rate. However, a shorter training program (12 weeks) was not effective in increasing heart antioxidant defense

Quality of Life after Breast Conservation versus Oncoplastic Surgery

Background: Quality of life (QOL) is becoming an important indicator of treatment efficacy in patients with breast cancer. Most previous studies have compared patients' QOL following breast conserving surgery (BCS) and mastectomy with or without reconstruction. Our aim was to assess the impact of BCS versus oncoplastic breast surgery (OBS). Methods: Selection of patients for BCS or OBS was performed according to standard criteria e.g the breast and tumor size. The QOL was assessed by employing EORTC QLQ-C3 and QLQ-BR23 questionnaires concurrently and one year after the surgery. The QOL scores one year after the surgery were compared between two groups using analysis of covariance, after adjusting for the baseline values. Results: A total of 120 patients with a mean age of 46.16±1.4 years were enrolled in the study. BCS and OBS were the main surgical treatment techniques in 57(47.5%) and 63(52.5%) patients, respectively. At the time of the last follow-up visit, there were no differences between the two groups regarding functional scales such as physical (P = 0.761), role (P = 0.356), emotional (P = 0.107), cognitive (P = 0.051), and social functioning (P = 0.659). No differences were observed between the two groups regarding nine symptom scales. Based on the results of breast cancer specific module of the questionnaire, no differences were observed in functional scales and symptoms with the exception of arm symptoms which were less common in OBS group (P = 0.023) Conclusions: Based on the results of the current study, it could be suggested that there are no significant differences in the in scores of QOL components between patients who received BCS or OBS

Mediterranean fever gene mutations in patients with idiopathic mesangial proliferative glomerulonephritis

Background: Familial Mediterranean Fever (FMF) is the most common inherited autoinflammatory disease. Kidney involvement in FMF is usually attributed to secondary amyloidosis. Non-amyloid glomerular involvement has also been reported. Objectives: We suppose that heterozygous mutation of Mediterranean fever (MEFV) gene could be the underlying cause in some cases of mesangial proliferative glomerulonephritis (MePGN) in FMF endemic area. Materials and Methods: This prospective study was done between 2013 and 2015 in NorthWest of Iran among the Azari-Turkish population. A panel of MEFV gene including M680I, R761H, M694V, R408Q, E148Q, A744S, F479L, P369S, V726A, M694I, and E167D were studied in a group of patients with idiopathic MePGN. Clinical characteristics and therapeutic responses were compared between those with and without a mutation. A total of 39 idiopathic MePGN patients and 156 healthy subjects were studied. Results: Heterozygote mutations of MEFV gene were detected in 11/39 (28.2%) of MePGN patients and 46/156 (17.3%) of controls. Clinical response regarding 24 hours urine protein excretion was significant in mutation-negative patients after 6 months of follow-up. Conclusions: This study shows a possible underlying role of heterozygous MEFV gene mutation in the clinical course of some case of idiopathic MePGN, particularly in FMF endemic population

Relationship between Helicobacter pylori cytotoxin-associated gene A protein with clinical outcomes in patients with rheumatoid arthritis

Introduction: The Helicobacter pylori (H. pylori)infection leads to intensification of symptoms and calenture of autoimmune diseases. This study aimed to evaluate the relationship between H. pylori infection and clinical outcomes in rheumatoid arthritis (RA)patients. Methodology: This study was performed on 100 RA patients. Blood samples were collected for measuring Anti-H. pylori IgG antibodies and cytotoxin-associated gene A (CagA)protein. Fresh fecal samples were also collected and the fecal H. pylori antigen was extracted. Clinical condition as well as severity and type of RA symptoms in both groups of H. pylori positive and H. pylori negative were also compared. Results: Serum levels of rheumatoid factor (RF), ESR, CRP, anti-cyclic citrullinated peptide (Anti−CCP), and anti-mutated citrullinated vimentin (Anti-MCV)were significantly higher in H. pylori positive patients than in H. pylori negative patients (P < 0.05). Serum RF, ESR, CRP and Anti-MCV levels were significantly higher in CagA positive patients than in CagA negative patients (P < 0.05). There were no significant differences in DAS-28 scores between H. pylori positive and H. pylori negative patients (P = 0.064)as well as between patients with positive and negative fecal H. pylori antigen (P = 0.237). However, DAS-28 score was significantly higher in CagA positive patients than in CagA negative patients (P < 0.001). Furthermore, mean VAS score was significantly higher in H. pylori positive patients (P = 0.031)and CagA positive patients (P = 0.004); however, there were no significant differences in VAS scores between patients with positive and negative fecal H. pylori antigen (P = 0.310). Conclusion: Follow-up and examination of RA patients in terms of infection with serum and fecal H. pylori organism and CagA seems necessary that will contribute to better and further control and treatment of the patients