31 research outputs found
Robust Attitude Control of an Agile Aircraft Using Improved Q-Learning
Get PDFAttitude control of a novel regional truss-braced wing (TBW) aircraft with low stability characteristics is addressed in this paper using Reinforcement Learning (RL). In recent years, RL has been increasingly employed in challenging applications, particularly, autonomous flight control. However, a significant predicament confronting discrete RL algorithms is the dimension limitation of the state-action table and difficulties in defining the elements of the RL environment. To address these issues, in this paper, a detailed mathematical model of the mentioned aircraft is first developed to shape an RL environment. Subsequently, Q-learning, the most prevalent discrete RL algorithm, will be implemented in both the Markov Decision Process (MDP) and Partially Observable Markov Decision Process (POMDP) frameworks to control the longitudinal mode of the proposed aircraft. In order to eliminate residual fluctuations that are a consequence of discrete action selection, and simultaneously track variable pitch angles, a Fuzzy Action Assignment (FAA) method is proposed to generate continuous control commands using the trained optimal Q-table. Accordingly, it will be proved that by defining a comprehensive reward function based on dynamic behavior considerations, along with observing all crucial states (equivalent to satisfying the Markov Property), the air vehicle would be capable of tracking the desired attitude in the presence of different uncertain dynamics including measurement noises, atmospheric disturbances, actuator faults, and model uncertainties where the performance of the introduced control system surpasses a well-tuned Proportional–Integral–Derivative (PID) controller
Consequences of AphanizomenonFlos-aquae(AFA) extract (StemtechTM) on metabolic profile of patients with type 2 diabetes
Get PDFBackground: Blue- green algae is one of the most nutrient dense foods which is rich in substances that have useful effects on human health. The purpose of this study was to evaluate the effectiveness of a water- soluble extract of the cyanophyta Aphanizomenon Flos-aquae (StemtechTM) as a functional supplement on CD markers, lipid profile, glucose levels as well as its side effects in Iranian patients with type 2 diabetes. Methods: During this randomized, double-blind, placebo-controlled trial 49 type 2 diabetic patients, aged between 20 and 60years with a HbA1C�7.5, were allocated. Patients were divided into two groups of placebo and treated with an equal ratio 1:1. The subjects in StemtechTM group received one capsule of StemFlo (508mg) before breakfast and two capsules of StemEnhance (500mg) after each meal for a period of 12weeks, and placebo group was instructed to take placebo with the same pattern. During the intervention period, subjects were asked to keep usual diet and prohibited to take any functional foods or dietary supplements. Metabolic panel has been measured as the primary outcome of study at the beginning and end of the intervention period via blood sampling. Results: StemtechTM supplementation for 12weeks decreased fasting blood glucose (FBG) and Glycatedhemoglobin (HbA1c). Mean serum chemistry parameters (Triglyceride, Total Cholesterol, LDL, HDL, CRP, AST, ALT, BUN and Creatinine) as well as CD 34+, IL-6, TNF-aα in treated and control groups before and after the study showed no considerable dissimilarities. Conclusion: StemtechTM intervention brought in positive consequence on blood glucose levels in Iranian patients with type 2 diabetes, consequently suggests the StemtechTM as a functional food for the management of diabetes. © 2015 Sanaei et al
Pulmonary metastases: Results of surgical resection in 60 cases: Treatment modalities other than surgery are needed
Get PDFPulmonary metastases occur in 30 of all oncology patients. Surgical resection of lung metastases is a widely accepted procedure but long-term results are disappointing with a 5-year survival rate of 20-40 and the results vary with the histologic type of the primary tumor. Due to unavailability of any study regarding pulmonary metastasectomy in Iran and emergence of new treatment modalities, reassessment of our current practices is essential. We performed a retrospective study of 60 cases of pulmonary metastasectomy during a 5-year period in one of the major thoracic surgery centers in Tehran (Imam Khomeini Hospital). Bilateral metastases were present in 23 of cases, number of metastases in each patient ranged from 1-12. Average disease-free interval was 12 months, pneumonectomy rate was 21.7 mostly as a second or third attempt and finally, recurrence or death following initial metastasectomy occurred in 12-18 months in most patients. These results confirm that surgery remains unsuccessful in obtaining long-term survival or cure in most patients with pulmonary metastases and treatment strategies other than surgery, such as radiofrequency ablation are needed to avoid performing multiple operations in these patients and improving their quality of life. © 2007 Tehran University of Medical Sciences. All rights reserved
Psychosis in Three Patients with Vitiligo
Get PDFAbstract:
Psychotic disorders have been observed in association with some autoimmune disorders. Moreover, autoimmune mechanisms have been recently considered in evaluation of schizophrenia spectrum disease managements. Vitiligo is one of the autoimmune diseases, but there is no report of vitiligo association with psychosis. We report three patients with vitiligo and schizophrenia spectrum disease that are indicative of the role of autoimmunity in psychosis. Moreover, unusual manifestation and poor response to treatment in the reported cases show that autoimmunity can complicate the prognosis of psychosis.
Keywords: Vitiligo, Autoimmune, Schizophrenia, Psychosi
Rare Variant of Lycanthropy and Ecstasy: Case Report
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Lycanthropy is an unusual belief or delusion in which the patient thinks that he/she has been transformed into an animal. In rare cases, the patient believes that another person has been transformed into an animal. In this case report, a patient who had an uncommon variant of lycanthropy is introduced. The patient’s symptoms had appeared after consumption of ecstasy. This shows the occurrence of uncommon and rare psychosis after ecstasy drug use especially in susceptible patients to schizophrenia. Ecstasy can induce paranoid psychosis similar to schizophrenia. It seems that in the presented case, ecstasy had a role in the incidence of the underlying suceptibility of the patient to schizophrenia.
Keywords: Lycanthropy, Methylenedioxymethamphetamine (MDMA
"PRIMARY PULMONARY LYMPHOMA WITH CAVITATION IN A 20-YEAR-OLD MALE PATIENT"
No full textPrimary lymphomas of the lung are rare and usual radiographic findings are adenopathy, effusion, multiple lesions, solitary lesion or diffuse lesion. This paper presents a case of primary malignant tumor of the lung with a very rare radiological presentation. A 20-year-old male patient was admitted to our hospital due to fever, chills, productive cough and later development of hemoptysis. Weight loss of 6 kg during a five month period was also noted. Physical examination was normal. Chest X-ray showed a right lower lobe mass with obliteration of diaphragmatic contour. Chest CT scan revealed cavitation in the mass. Laboratory tests and bronchoscopy were also normal. Surgical resection of the mass via right lower lobectomy revealed the pathological diagnosis of intermediate grade mixed large and small cell lymphoma. Cavitation in this uncommon tumor of the lung is very rare and has been reported very infrequently
Numerical and Experimental Study of a Wing Combined with Wing Grids in Low Reynolds Number Flows
No full textOne of the reasons for the increase in induced drag is the vortices created at the wing tip, which has a significant effect on reducing aerodynamic efficiency. Therefore, in order to reduce vortices and the induced drag as well as to improve the aerodynamic performance, the use of wing grid is recommended. Wing grids perform better at low Reynolds numbers, and combination of parameters such as taper ratio, aspect ratio, and twist has a better effect on wing performance and reducing turbulence intensity and induced drag. The purpose of this paper is to improve the aerodynamic performance of compound wing using the wing grids. In this study, the numerical and experimental approaches have been used to investigate the effect of these parameters and also, two key parameters: the grid dihedral angle and sweep angle. Also, a force balance test has been performed for force analysis and numerical solution validation. Wing grid dihedral angle decreases induced drag by increasing the space between separated tip vortices and prevents reinforcing effects due to superposition. On the other hand, dihedral angle should be arranged to increase the aerodynamic efficiency. In other words, increase in dihedral angle may defect the overall performance of the wing. The optimum configuration is found to be symmetric, where the dihedral distribution with a 40° angle for the first grid is reduced gradually to a value of -20° for the last one. In addition, sweep angle distribution for the obtained optimized dihedral angle is also investigated. Initially, each grid span is decreased from the first grid to the last at a constant rate. This increases the sweep angle and enhances the aerodynamic efficiency by 15%. Furthermore, the span of the side grids is reduced from the middle grid and marching the wing leading and trailing edges. Elliptical wing configuration has also been shown to increase aerodynamic efficiency by approximately 50%
SEISMIC PERFORMANCE ASSESSMENT OF ISOLATED STEEL MOMENT FRAMES WITH LOSS APPROACH
No full textEarthquakes pose inevitable damage and loss of life in structures. Seismic isolation has proven to be an effective method to reduce the seismic vibration and mitigate seismic losses and damage costs. The isolator drastically reduces the main frequency of the structure and subsequently lowers the acceleration of the floors. While this flexible layer protects the building from destruction,
it undergoes a relatively large displacement demand. Isolated structures as well as fixed structures could suffer from inelastic deformation and serious damage under intense seismic ground motions. Performance-based seismic design (PBSD) is a concept that permits the design of buildings with reliable understanding of the risk of life, occupancy, and economic loss that may occur as a result of future earthquakes. Also, Seismic loss estimation method combines seismic hazard, structural response, damage fragility, and damage consequences of allowing quantification of seismic risk based on seismic performance of a building is expressed as the probable damage and resulting consequences of a building's response to earthquake shaking. Nonlinear 4-story archetypes of conventional special moment resisting frame and isolated intermediate moment resisting frame were compared with each other under Far-Field and Near-Field ground motions. Detailed three-dimensional (3D) numerical models of the structures were developed in OpenSees software and Performance Assessment Calculation Tool (PACT) was used for the loss estimation of archetypes. The decision variables in this study were defined as expected annualized repair cost or financial losses (EAL) and expected annualized fatalities (EAF). The analysis results showed that seismic isolation reduces collapse probability, EAL and EAF in superstructures significantly and can be cost effective in mitigating seismic risk. Seismic isolation reduces EAL by 72\% and 67\% under Far-Field and Near-Field ground motions, respectively. Furthermore the result of this study showing that the effectivity of isolation system decreases in Near-Field compared with Far-Field ground motions. The economic feasibility studies showed that if isolation system is used, pay-back period times are around 14 and 18 years under Far-Field and Near-Field ground motions, respectively. The benefit of loss estimation approach is an improved method to assess the effectiveness of isolation system in terms of loss estimation
Characteristics Of Congenital Chest Wall Deformities In Referred Patients To Tehran Imam Khomeini And Kashan Shahid Beheshti Hospital During 1991-2001
No full textBackground: Infants and children present with a wide range of congenital chest wall deformities which have both physiologic psychologic consequences and are often associated with other abnormalities. Surgical intervention offers excellent cosmetic results with minimal morbidity and mortality. In order to investigation of chest wall deformities, and surgical results, this study was performed. Materials and Methods: A descriptive study on existing data on 60 consecutive patients with chest wall deformity during 10 years carried out. Patient's characteristics such as age, gender, signs and symptoms type of operation, associated disorder, syndrome, and surgical complications were considered. Results: Pectus excavatum 60% and pectus carinatum 30% Poland syn 6.7% 9 sternal cleft 3.2. Inpectus, M/F: Was 3/1 and others were 1:1. Age of admission 4 to 27 years 13.4±6.82) and association syndromes were, turner, Morgue and marfan, most patients were operated in delayed time (75) and hence, scoliosis was common than others. Conclusion: Pectus excavatum was the most common deformity and if scoliosis was prominent and most operation was done in old age but surgical result was excellent no anyone expired and complication was a little. So we recommended that all of the chest deformities must be operated in anytime
Healthcare professionals-related factors affecting parents' participation in decision making for neonates with life-threatening conditions: A qualitative study
No full textRationale, aims, and objectives: Neonates with life-threatening conditions face complex clinical circumstances that confront parents and professionals with ethical decisions. Parents' participation in decision making has not gained sufficient attention in practice. Understanding factors affecting parents' participation is required. This study is part of a comprehensive project that explored the process of parents' participation in decision making for neonates with life-threatening conditions. The current study aimed to explore healthcare professionals-related factors affecting parents' participation in decision-making for neonates with life-threatening conditions. Methods: A grounded theory methodology was used in the comprehensive project. Twenty-two interviews/68 hours of observation were conducted. Data were concurrently analysed throughout data generation and constant comparative analysis. Data collected until theoretical saturation was reached, the extracted categories were coherent and the emerging theory made sense. After coding stages, the core category and the relationships with other main categories involved in the process of parents' participation in decision-making were developed. For this study, the category reflecting healthcare professionals-related factors affecting parents' participation in decision-making was reported. Results: Four themes were found: risk aversion including fear of litigation, fear of being accountable to the parents, and fear of bearing emotional distress; unprofessionalism including poor adherence to professional ethics, inadequate skill/knowledge, poor communication, and nurses' negligence in playing their professional role; information deficiencies including insufficient information, conflicting information, and complex and technical information, and clashes of attitudes including conflict about parents' participation in decision-making and conflict about the best interest of neonates. Conclusion: Professionals should be aware of their role in involving parents in decision making. Training professionals on family centred care principle and communication skills contribute to support parents emotionally and respond empathically to their negative expressions. Training on ethics, development, and dissemination of guidelines and rules of conduct can make professionals more sensitive to ethical aspects of their work and may reduce their fear of litigation. © 2020 John Wiley & Sons Lt
