B-spline neural networks based PID controller for Hammerstein systems

A new PID tuning and controller approach is introduced for Hammerstein systems based on input/output data. A B-spline neural network is used to model the nonlinear static function in the Hammerstein system. The control signal is composed of a PID controller together with a correction term. In order to update the control signal, the multi-step ahead predictions of the Hammerstein system based on the B-spline neural networks and the associated Jacobians matrix are calculated using the De Boor algorithms including both the functional and derivative recursions. A numerical example is utilized to demonstrate the efficacy of the proposed approaches

Lorenz-like systems and classical dynamical equations with memory forcing: a new point of view for singling out the origin of chaos

A novel view for the emergence of chaos in Lorenz-like systems is presented. For such purpose, the Lorenz problem is reformulated in a classical mechanical form and it turns out to be equivalent to the problem of a damped and forced one dimensional motion of a particle in a two-well potential, with a forcing term depending on the ``memory'' of the particle past motion. The dynamics of the original Lorenz system in the new particle phase space can then be rewritten in terms of an one-dimensional first-exit-time problem. The emergence of chaos turns out to be due to the discontinuous solutions of the transcendental equation ruling the time for the particle to cross the intermediate potential wall. The whole problem is tackled analytically deriving a piecewise linearized Lorenz-like system which preserves all the essential properties of the original model.Comment: 48 pages, 25 figure

B-spline neural networks based PID controller for Hammerstein systems

A new PID tuning and controller approach is introduced for Hammerstein systems based on input/output data. A B-spline neural network is used to model the nonlinear static function in the Hammerstein system. The control signal is composed of a PID controller together with a correction term. In order to update the control signal, the multi-step ahead predictions of the Hammerstein system based on the B-spline neural networks and the associated Jacobians matrix are calculated using the De Boor algorithms including both the functional and derivative recursions. A numerical example is utilized to demonstrate the efficacy of the proposed approaches

Adenomyolipoma of the uterus: A case report

Adenomyolipoma of the uterus is a rare, benign, polypoid lesion considered to be of hamartomatous origin or represent an unusual type of benign Mullerian mixed tumour with a heterologous element. The authors present a case of uterine adenomyolipoma and discuss its pathogenesis. A 62-year-old woman complained of lower abdominal pain and post-menopausal bleeding. Imaging techniques revealed a solid ovarian mass and a polypoid intrauterine lesion. The frozen section diagnosis of the ovarian mass was a thecoma. A total hysterectomy and bilateral salpingo-oophorectomy were performed. On gross examination a pedunculated, polypoid lesion of 7x4.5x3 cm was found in the uterine cavity. Microscopically, the polypoid lesion contained both epithelial and mesenchymal elements. The epithelial elements were endometrial glands of various size, formed by proliferative endometrial cells. The mesenchymal elements were composed of endometrial stroma, smooth muscle and mature adipocytes. Both the epithelial and the mesenchymal elements showed a benign appearance, were intermingled with each other and periglandular stromal condensation was absent. The lesion had an irregular surface. Microscopic diagnosis was an adenomyolipoma. The peculiar shape and microscopic features of this lesion suggested that it was a variant of benign Mullerian mixed tumour

Hamartomatous endocervical polyp with heterologous mesenchymal tissue

We present an endocervical polyp with heterologous elements. Although a few neoplastic cervical lesions with cartilaginous and adipocytic heterologous tissue have been reported, an endocervical polyp with heterologous cartilage and adipose tissue has not been reported before our case. The patient was a 33-year-old woman who presented with abnormal uterine bleeding. On physical examination, there were no remarkable findings other than a cervical polyp protruding into the cervical canal. The polyp was removed. Pathological examination revealed an endocervical polyp with typical epithelial features. The stroma of the polyp contained mature cartilage islands and adipose tissue. There were also many thick-walled vascular structures. Neither stromal periglandular condensation nor atypia was found. Mitotic figures were not observed. Arteriolar structures did not contain internal elastic lamina. In our opinion, these pathological findings are all consistent with a hamartomatous lesion rather than with a true neoplasm

Application

This paper presents a study on predicting academically at-risk engineering students at the early stage of their education. For this purpose, some soft computing tools namely support vectors machines and artificial neural networks have been employed. The study population included all students enrolled in Pamukkale University, Faculty of Engineering at 2008-2009 and 2009-2010 academic years as freshmen. The data are retrieved from various institutions and questionnaires conducted on the students. Each input data point is of 38-dimension, which includes demographic and academic information about the students, while the output based on the first-year GPA of the students falls into either at-risk or not. The results of the study have shown that either support vector machine or artificial neural network methods can be used to predict first-year performance of a student in a priori manner. Thus, a proper course load and graduation schedule can be transcribed for the student to manage their graduation in a way that potential dropout risks are reduced. Moreover, an input sensitivity analysis has been conducted to determine the importance of each input used in the study

energized by photovoltaic-wind/fuel cell hybrid energy systems

Renewable energy systems are of importance as being modular, nature-friendly and domestic. Among renewable energy systems, a great deal of research has been conducted especially on photovoltaic effect, wind energy and fuel cell in the recent years. In this study, a residential application of photovoltaic-wind/fuel cell hybrid energy system established at the Clean Energy House in Denizli, Turkey, has been investigated. The study is based on the distribution and consumption of Direct Current (DC) electrical energy which is produced by the hybrid system. (C) 2010 Elsevier B.V. All rights reserved

Prognostic role of nm23 gene expression in patients with ovarian cancer.

The aim of the study was to define the prognostic role of the metastasis suppressor gene, nm23, in 50 patients with primary ovarian cancer. Immunohistochemical analysis was performed on formalin-fixed, paraffin-embedded specimens by the primary nm23 monoclonal antibody (Novocastra, NCL-nm23 clone 37.6). Forty-two specimens (84%) showed a positive nm23 staining. The nm23 staining was more intensive in patients with normal serum CA19.9 levels, patients with non-recurrent disease, and alive patients (p < 0.05). Nm23 expression did not correlate with common clinicopathologic parameters such as histology, grade of differentiation, International Federation of Gynecology and Obstetrics stage, and CA-125. Although the difference was not statistically significant (p = 0.11), we found that nm23 may have a favorable prognostic factor in ovarian cancer. To clarify this subject further, prospective studies on a larger population are needed

A SENSITIVE STAINING METHOD FOR NORS

A sensitive staining method for nucleolar organizer regions (NORs) is described, using blue toning of AgNORs. NORs are loops of DNA which are transcribed into ribosomal RNA. NORs can be demonstrated by staining with silver nitrate, since NOR-associated proteins are argyrophilic, producing structures termed AgNORs. Normal blood lymphocytes were stained with both methods. The number and resolution of NORs increased 2-3 times by blue toning (30 mmol/l FeCl3, 11 mmol/l potassium hexacyanoferrate(III), and 33 mmol/l oxalic acid) compared with silver staining. A significant difference in the number of NORs was noticed between silver-stained and blue-toned cells (P<0.001). The blue toning technique thus appears to be more sensitive in detecting NORs than the AgNOR method and may prove a useful alternative for applications in histopathology