Teacher-directed learning in view-independent face recognition with mixture of experts using single-view eigenspaces

We propose a new model for view-independent face recognition by multiview approach. We use the so-called “mixture of experts”, ME, in which, the problem space is divided into several subspaces for the experts, and the outputs of experts are combined by a gating network. In our model, instead of leaving the ME to partition the face space automatically, the ME is directed to adapt to a particular partitioning corresponding to predetermined views. To force an expert towards a specific view of face, in the representation layer, we provide each expert with its own eigenspace computed from the faces in the corresponding view. Furthermore, we use teacher-directed learning, TDL, in a way that according to the pose of the input training sample, only the weights of the corresponding expert are updated. The experimental results support our claim that directing the experts to a predetermined partitioning of face space improves the performance of the conventional ME for view-independent face recognition. In particular, for 1200 images of unseen intermediate views of faces from 20 subjects, the ME with single-view eigenspaces yields the average recognition rate of 80.51% in 10 trials, which is noticeably increased to 90.29% by applying the TDL method.     

A new approach for constrained chaos synchronization with application to secure data communication

In this paper, a new technique is introduced for chaos secure data communication. In this approach, in addition to the usually used techniques for data encryption, the concept of carrier encryption is introduced to increase the security level of the secure communication scheme. To fulfill this objective, at the transmitting end, two chaotic oscillators are coupled, and a set of inequality time dependent constraints with time dependent bounds is imposed on the generated chaotic signals. Moreover, to increase system complexity and its security level, the imposed set of constraints and their bounds are allowed to be changeable from one time period to another during the transmission process. As a result, the patterns of the generated chaotic signals are completely changed and the chaotic oscillator is completely encrypted. At the receiving end, the newly developed Constrained Smoothed Regularized Least Square (CSRLS) observer is used to synchronize the received constrained chaotic signals and hence retrieve the transmitted data. Using such an approach, the quality of the received information, measured by the Bit Error Rate (BER), is highly improved due to the superior performance of the developed CSRLS observer. The stability of the observer is analyzed, and simulation results are presented to show the efficiency and effectiveness of the proposed secure communication scheme.     

Online learning of an interval type-2 TSK fuzzy logic controller for nonlinear systems

In this study, an adaptive interval type-2 Takagi-Sugeno-Kang fuzzy logic controller based on reinforcement learning (AIT2-TSK-FLC-RL) is proposed. The proposed controller consists of an actor, a critic and a reward signal. The actor is represented by the IT2-TSK-FLC in which the antecedents and the consequents are interval type-2 fuzzy sets (IT2FSs) and type-1 fuzzy sets (T1FSs), respectively, which are named A2-C1. The critic is represented by a neural network, which approximates the optimal guaranteed cost in the control design to ensure the system stability for all admissible uncertainties and noise. The use of a reward signal to formalize the idea of a goal is one of the most distinctive features of RL. Thus, the proposed controller evolves in time as a result of the online learning algorithm. The parameters of the proposed controller are learned online based on the Lyapunov theorem to guarantee the stability, overcome the shortcomings of the gradient descent, such as the local minima and instability, and determine the learning rate of the IT2-TSK-FLC controller. Furthermore, the critic stability is discussed for determining the optimal learning rate. The proposed controller is applied to uncertain nonlinear systems to show its robustness in reducing the effect of system uncertainties and external disturbances and is compared to other controllers.     

Characterization and Classification of Mesenchymal Stem Cells in Several Species Using Surface Markers for Cell Therapy Purposes

Mesenchymal stem cells are multipotent cells capable of replicating as undifferentiated cells, and have the potential of differentiating into mesenchymal tissue lineages such as osteocytes, adipocytes and chondrocytes. Such lineages can then be used in cell therapy. The aim of present study was to characterize bone marrow derived mesenchymal stem cells in four different species, including: sheep, goat, human and mouse. Human bone-marrow mesenchymal stem cells were purchased, those of sheep and goat were isolated from fetal bone marrow, and those of mouse were collected by washing bone cavity of femur and tibia with DMEM/F12. Using flow-cytometry, they were characterized by CD surface antigens. Furthermore, cells of third passage were examined for their osteogenic and adipogenic differentiation potential by oil red and alizarin red staining respectively. According to the results, CD markers studied in the four groups of mesenchymal stem cells showed a different expression. Goat and sheep expressed CD44 and CD166, and weakly expressed CD34, CD45, CD105 and CD90. Similarly, human and mouse mesenchymal cells expressed CD44, CD166, CD105 and CD90 whereas the expression of CD34 and CD45 was negative. In conclusion, although all mesenchymal stem cells display plastic adherence and tri-lineage differentiation, not all express the same panel of surface antigens described for human mesenchymal stem cells. Additional panel of CD markers are necessary to characterize regenerative potential and possible application of these stem cells in regenerative medicine and implantology.     

Robust simultaneous fault detection and control for a class of nonlinear stochastic switched delay systems under asynchronous switching

This paper concerns the simultaneous fault detection and control (SFDC) problem for a class of nonlinear stochastic switched systems with time-varying state delay and parameter uncertainties. The switching signal of detector/controller unit (DCU) is assumed to be with switching delay, which results in the asynchronous switching between the subsystems and DCU. By constructing a switching strategy depending on the state and switching delays, new sufficient conditions expressed by a set of linear matrix inequalities (LMIs) is derived to design DCU gains. This problem is formulated as an H_∞ optimization problem and both mean square exponential stability and fault detection of augmented system are considered. A numerical example is finally exploited to verify the effectiveness and potential of the achieved scheme.     

Association of Prooxidant–Antioxidant Balance with Clinical and Laboratory Parameters and Its Relation to Different Drug Regimens in Polycystic Ovary Syndrome Women with Normal BMI

Polycystic ovarian syndrome is one of the most common hormonally leading cause infertility disorders. The effect of oxidant-antioxidant imbalance on disease progression has been studied in many disorders. The present study was aimed to evaluate prooxidant–antioxidant balance (PAB) in patients with polycystic ovarian syndrome compared to healthy subjects. We also studied the possible effect of treatment with available drugs on serum PAB. In this case–control study 100 polycystic ovary syndrome (PCOS) patients and 100 healthy individuals were enrolled in the study. The laboratory features of patients and controls like as serum LH and FSH concentration and hematological examinations were collected. PAB was evaluated by a colorimetric method. Serum PAB value was significantly higher before treatment compared to after treatment and healthy subjects. PAB values were also higher in subjects with irregular menstrual cycle compared to normal subjects. Our results represented that serum PAB values has an indirect significant correlation with serum LH concentration. We also found that drugs regimen containing spironolactone effectively reduced the serum PAB values. Our results showed that PCOS patients had increased level of PAB and treatment with spironolactone mainly decreases the level of serum PAB. Our results indicate that the measurements of PAB may be used as a potential laboratory marker for assessment of PCOS patients.     

Beneficial Effect of Aqueous Garlic Extract on Inflammation and Oxidative Stress Status in the Kidneys of Type 1 Diabetic Rats

One of the most important complications of diabetes is nephropathy. This study investigates the effects of aqueous garlic extract on inflammation and oxidative stress status in the kidneys of diabetic rats. Male rats were divided into four groups- control rats, diabetic rats, garlic extract-treated diabetic rats, garlic extract-treated normal rats. The glucose, urea, uric acid, and creatinine levels were measured in sera using colorimetric methods. To determine the oxidative stress condition in the kidney tissues, total antioxidant capacity (TAC), malondialdehyde (MDA), and total oxidant status (TOS) were measured using colorimetric methods. Inflammation status was evaluated by the determination of tumor necrosis factor-alpha (TNF-α) gene and protein expression using qRT-PCR and ELISA respectively, while nitric oxide (NO) level in these tissues was measured using the Griess method. Histological examination of Kidneys was carried out by H&E staining. The levels of glucose, urea, and uric acid were found to increase in the serum of diabetic rats and decrease in that of diabetic rats after treatment with garlic. Measurement of MDA, TOS, and TAC revealed oxidative stress in diabetic rats, which improved after receiving the extract. The NO and TNF-α protein levels in diabetic rats were higher than those in control rats. After treatment with garlic, the levels of TNF-α protein and NO became close to the normal levels. Histological results confirmed certain other data as well. Garlic has antioxidant properties; therefore, it can reduce oxidative stress, which plays an important role in the development of diabetic nephropathy. Reduction in oxidative stress has beneficial effects on inflammation because it leads to a decrease in the level of TNF-α.     

Convexity of the Energy Domain

A basic theorem describing the convexity of the energy domain for the general family of linear time-invariant (active or passive, reciprocal or non-reciprocal, lumped or distributed, single variable or multivariable) physical system {T} is proved.Theorem: Let F = P + jQ represent the complex energy associated with any linear physical system T (n-port). For any specified excitation of frequency s and the family of constant energy content input signals {i:∥i∥= constant}, the point F describes a convex domain in the {P;Q} plane.Part I contains a mathematical and a network theoretic proof of the foregoing theorem. In Part II the geometric nature of the energy loci for the two-ports is examined. It is shown that for all two-ports with double eigenvalves the energy domain is circular. For two-ports with distinct eigenvalves, the convex energy domain is an ellipse. The geometric characterization of this elliptic domain is examined and examples verified by computer.The concept of convexity is frequently exploited in optimization of energy in electric power system and quadratic cost functions in control theory. In this respect the central theorem of this paper, its proof and geometric ramifications should prove to be of basic interest for all linear systems.