Adaptive fuzzy sliding mode controller for linear systems with mismatched time-varying uncertainties

A new design approach for an adaptive fuzzy sliding mode controller (AFSMC) for linear systems with mismatched time-varying uncertainties is presented. The coefficient matrix of the sliding function can be designed to satisfy a sliding coefficient matching condition provided time-varying uncertainties are bounded. With the sliding coefficient matching condition satisfied, an AFSMC is proposed to stabilize the uncertain system. The parameters of output fuzzy sets in the fuzzy mechanism are on-line adapted to improve the performance of the fuzzy sliding mode control system. The bounds of uncertainties are not required to be known in advance for the AFSMC. Stability of the fuzzy control system is guaranteed and the system is shown to be invariant on the sliding surface. Moreover, chattering around the sliding surface in sliding mode control can be reduced by the proposed design approach. Simulation results are included to illustrate the effectiveness of the proposed AFSMC.

Radial basis function networks with linear interval regression weights for symbolic interval data

This paper introduces a new structure of radial basis function networks (RBFNs) that can successfully model symbolic interval-valued data. In the proposed structure, to handle symbolic interval data, the Gaussian functions required in the RBFNs are modified to consider interval distance measure, and the synaptic weights of the RBFNs are replaced by linear interval regression weights. In the linear interval regression weights, the lower and upper bounds of the interval-valued data as well as the center and range of the interval-valued data are considered. In addition, in the proposed approach, two stages of learning mechanisms are proposed. In stage 1, an initial structure (i.e., the number of hidden nodes and the adjustable parameters of radial basis functions) of the proposed structure is obtained by the interval competitive agglomeration clustering algorithm. In stage 2, a gradient-descent kind of learning algorithm is applied to fine-tune the parameters of the radial basis function and the coefficients of the linear interval regression weights. Various experiments are conducted, and the average behavior of the root mean square error and the square of the correlation coefficient in the framework of a Monte Carlo experiment are considered as the performance index. The results clearly show the effectiveness of the proposed structure.

An approximation of interval type-2 fuzzy controllers using fuzzy ratio switching type-1 fuzzy controllers

In this paper, the interval type-2 fuzzy controllers (FC(IT2)s) are approximated using the fuzzy ratio switching type-1 FCs to avoid the complex type-reduction process required for the interval type-2 FCs. The fuzzy ratio switching type-1 FCs (FC(FRST1)s) are designed to be a fuzzy combination of the possible-leftmost and possible-rightmost type-1 FCs. The fuzzy ratio switching type-1 fuzzy control technique is applied with the sliding control technique to realize the hybrid fuzzy ratio switching type-1 fuzzy sliding controllers (HFSC(FRST1)s) for the double-pendulum-and-cart system. The simulation results and comparisons with other approaches are provided to demonstrate the effectiveness of the proposed HFSC(FRST1)s.

A reduction approach for fuzzy rule bases of fuzzy controllers

In this paper, a new approach to reducing the number of rules in a given fuzzy rule base of a fuzzy controller is presented. The fuzzy mechanism of the fuzzy controller under consideration consists of the product-sum inference, singleton output consequents and centroid defuzzification. The output consequents in the cells of the rule table are collected and represented as an output consequent matrix. The feature of the output consequent matrix is extracted by the singular values of the matrix. The output consequent matrix is reasonably approximated with a dominant consequent matrix. Also, the elements of the dominant consequent matrix is determined to minimize the approximation error function. Then the size of the dominant consequent matrix (the size of the fuzzy rule base) is reduced through the rule combination approach. The scaling factors for the fuzzy controller with the reduced rule table are adjusted to have the control system satisfy the performance indices. The effectiveness of the proposed approach is shown using simulation and experimental results.

Segmentation of psoriasis vulgaris images using multiresolution-based orthogonal subspace techniques

In this paper, a method is proposed for the segmentation of color images using a multiresolution-based signature subspace classifier (MSSC) with application to psoriasis images. The essential techniques consist of feature extraction and image segmentation (classification) methods. In this approach, the fuzzy texture spectrum and the two-dimensional fuzzy color histogram in the hue-saturation space are first adopted as the feature vector to locate homogeneous regions in the image. Then these regions are used to compute the signature matrices for the orthogonal subspace classifier to obtain a more accurate segmentation. To reduce the computational requirement, the MSSC has been developed. In the experiments, the method is quantitatively evaluated by using a similarity function and compared with the well-known LS-SVM method. The results show that the proposed algorithm can effectively segment psoriasis images. The proposed approach can also be applied to general color texture segmentation applications.

Design of sliding mode controllers for bilinear systems with time varying uncertainties

Sliding mode controllers for the bilinear systems with time varying uncertainties are developed in this paper. The bilinear coefficient matching condition which is similar to the traditional matching condition for linear system is defined for the homogeneous bilinear systems. It can be seen that the bilinear coefficient matching condition is very limited and is not generally applicable to the nonhomogeneous bilinear system. Thus, the sliding coefficient matching condition is also considered for the bilinear systems with time varying uncertainties. Then, the sufficient conditions are provided for the reaching mode of the time varying uncertain bilinear systems to be guaranteed by the designed sliding mode controllers. Moreover, the stability of the uncertain bilinear systems with the sliding mode controller is discussed. Simulation results are included to illustrate the effectiveness of the proposed sliding mode controllers.

Adaptive Fuzzy Terminal Sliding Mode Controller for Linear Systems With Mismatched Time-Varying Uncertainties

A new design approach of an adaptive fuzzy terminal sliding mode controller for linear systems with mismatched time-varying uncertainties is presented in this paper. A fuzzy terminal sliding mode controller is designed to retain the advantages of the terminal sliding mode controller and to reduce the chattering occurred with the terminal sliding mode controller. The sufficient condition is provided for the uncertain system to be invariant on the sliding surface. The parameters of the output fuzzy sets in the fuzzy mechanism are adapted on-line to improve the performance of the fuzzy sliding mode control system. The bounds of the uncertainties are not required to be known in advance for the presented adaptive fuzzy sliding mode controller. The stability of the fuzzy control system is also guaranteed. Moreover, the chattering around the sliding surface in the sliding mode control can be reduced by the proposed design approach. Simulation results are included to illustrate the effectiveness of the proposed adaptive fuzzy terminal sliding mode controller.

Studies on anthracenes. 2. Synthesis and cytotoxic evaluation of 9-acyloxy 1,8-dichloroanthracene derivatives

The synthesis and cytotoxic evaluation of 9-acyloxy 1,8-dichloroanthracene derivatives are described. The system selectively reduces the carbonyl group flanked by the peri substituents of the anthracenediones to give the corresponding 1,8-dichloro-9(10H)-anthracenone. Simple acylation of anthracenone occurred with appropriate acyl chlorides in CH2Cl2 with a catalytic amount of pyridine to give the 9-acyloxy-1,8-dichloroanthracene derivatives. Considerable interest has developed in the mechanism of how anthracenones achieve this desirable selectivity. These compounds were evaluated in vitro for their ability to inhibit the growth of human oral epidermoid carcinoma cells (KB cell line), human cervical carcinoma cells of ME 180 (GBM 8401) and Chinese hamster ovary (CHO) cells, respectively, as compared to mitoxantrone. The in vitro cytotoxicity evaluation of 9-acyloxy 1,8-dichloroanthracenes against these above cell lines revealed for most of the compounds a cytotoxic potency lower than that of mitoxantrone. The most active compounds were thus selected for further in vitro biological evaluation and structural modification.

Studies on anthracenes. 3. Synthesis, lipid peroxidation and cytotoxic evaluation of 10-substituted 1,5-dichloro-9(10H)-anthracenone derivatives

The synthesis of a series of 1,5-dichloro-9(10H)-anthracenones bearing O-linked and N-linked substituents in the 10-position are described. Previous studies have shown that 9-acyloxy 1,5-dichloroanthracenes and 9-acyloxy 1,8-dichloroanthracenes displayed a potential cytotoxic effect. These results have encouraged us in further investigation of potential anthracenone derivatives. Therefore, a series of 10-substituted 1,8-dichloro-9(10H)-anthracenone derivatives were synthesized. These compounds were evaluated for their ability to inhibit the growth of human oral epidermoid carcinoma cells (KB cell line), human cervical carcinoma cells of ME 180 (GBM 8401) and Chinese hamster ovary (CHO) cells, respectively. Compounds 3c and 4c of this series compare favorably in the KB cellular assay with mitoxantrone. Compound 4c showed combined inhibitory action against KB, GBM and CHO cell growth, respectively. In addition, redox property of the compounds for the inhibition of lipid peroxidation in model membranes was determined. Compounds 4b and 4d exhibited stronger antioxidant activity than ascorbic acid, (+)-alpha-tocopherol and mitoxantrone, respectively.

Design of fuzzy controllers with adaptive rule insertion

In this paper, an approach of designing adaptive fuzzy controllers is presented to systematically develop efficient and effective rules for fuzzy controllers. The proposed fuzzy controllers are first designed with two basic fuzzy if-then rules. Then according to the design requirements of the fuzzy control system, new fuzzy if-then rules are inserted into the rule-base structure of the fuzzy controller. Initially the inserted fuzzy rules are redundant in the sense that the resultant input-output mapping of the fuzzy rules remains intact. After that the parameters of the membership functions for the fuzzy sets of the newly added fuzzy rules are trained on-line to minimize predefined cost functions. Thus, efficient fuzzy controllers can be systematically designed. Simulations for linear, nonlinear, and delayed systems are provided to show the effectiveness of the proposed approach.

Design and analysis of region-wise linear fuzzy controllers

In this paper, a methodology to reduce the complexity of a robust controller based on fuzzy if-then rules is proposed. The motivation and the design of this complexity-reduced fuzzy controller are presented. This fuzzy controller with the triangular membership functions and fuzzy partition methods used here leads to a region-wise linear fuzzy controller (RLFC). The properties of the region-wise linear fuzzy controllers are discussed and the reasons why they in general perform better than the PD controllers are also provided. And the simulation results based on a second order plant are included to show that the region-wise linear fuzzy controller outperforms the PD controller. We also show that the region-wise linear fuzzy controller and original fuzzy controller have similar performances.

Carcinosarcoma of the lung: an analysis of 6 operated cases

BACKGROUND

Carcinosarcoma of the lung is a rare malignant pulmonary neoplasm, and constitutes 0.1% to 0.3% of all lung tumors. Typically, these tumor have both carcinomatous and sarcomatous components with a poor prognosis due to late diagnosis and early metastases.

METHODS

From July 1980 to December 1993, six patients with pulmonary carcinosarcoma who underwent surgical treatment were studied. None of them had accurate tissue diagnosis before operation except one case with peripheral variant carcinosarcoma who was diagnosed by percutaneous transthoracic fine needle biopsy under sonographic guidance. All of our patients had a huge peripheral lung tumor 3.8 to 10 cm in diameter. Pneumonectomy was done in two patients, and lobectomy in three. The other patient had unresectable tumor.

RESULTS

The histopathological components in carcinoma were epidermoid carcinoma in and adenocarcinoma in 3. Differentiation of sarcomatous lesions included spindle cell sarcoma in 3, fibrosarcoma in 2 and undifferentiated mesenchymal sarcoma in one patient. In the resectable group, 1 was at stage II and 4 were at stage IIIa. None of the patients survived more than 2 years due to distant metastasis and cachexia. The mean survival was 140 days.

CONCLUSIONS

The carcinomatous portion tends to metastasize to regional lymph nodes whereas the sarcomatous part gives rise to systemic dissemination. Due to early systemic dissemination and poor prognosis, combination of extensive surgical intervention resection with aggressive postoperative chemotherapy and radiotherapy might be a reasonable consideration to improve survival in primary pulmonary carcinosarcoma.

Anomalous systemic arterial supply to normal basilar segments of the left lower lobe of the lung: a case report

We present a patient who had suffered from mild hemoptysis for six years. Abnormal bronchovesicular breath sounds over the left lower lung filed were noted. The chest film also revealed infiltration over the left lower lung field. High-resolution computed tomography (HRCT), aortogram and pulmonary angiography demonstrated anomalous arterial supply to the basilar segments of the left lower lung without coexistence of pulmonary sequestration. Only total nine cases have been reported in English or Chinese literature. The improvement of diagnostic method has enabled an accurate diagnosis before operation with non-invasive examination. Also, this congenital abnormality may not be so rare if meticulously surveyed.

Use of a closed-airway suctioning system during anesthesia

We evaluated the efficacy of a closed airway suctioning (CAS) system in sixteen ASA Class I-II patients undergoing surgery of the extremities. All patients were anesthetized with 50% N2O and oxygen with adequate halogenated anesthesia. Full muscle relaxation was provided and all patients were ventilated with an anesthesia volume controlled ventilator. Endotracheal suctioning without preoxygenation was performed during anesthesia in randomly selected patients by either the CAS or the standard suctioning (SS) technique with a 30 minute rest period between suctioning. Both CAS and SS, used 14Fr catheters, were applied intermittently for 15 seconds at (-)150 mmHg suctioning pressure. SaO2 was continuously monitored throughout the suction period by a pulse oximeter. Arterial blood gas sample was drawn before each suction and 30 sec., 1 min, 3 min, 5 min, 10 min, 15 min, 30 min afterwards. No alteration of SaO2 or PaO2 was noted during CAS but significant lowering of PaO2 was noted for SS at the 30 seconds and 1 minutes post-suctional points. Potential advantages of CAS include: 1) PEEP can be maintained during suctioning. 2) Operating room pollution is minimized. 3) Accidental contamination of both the patient and the anesthesiologist can be prevented. 4) Time is saved during frequent intraoperative suctioning as no preoxygenation is required. 5) There is no need to turn off the anesthetic gases. We conclude that as CAS can maintain steady PaO2 during airway suctioning, it may be a better alternative for repeated intraoperative suctioning.

Pulmonary carcinosarcoma: diagnostic approach by fine needle aspiration biopsy

Carcinosarcoma of the lung is an exceedingly uncommon malignancy, possessing both malignant epithelial and mesenchymal elements. There are less than 100 cases reported in the English literature to date. Most of them were diagnosed by autopsy and surgery. Now we present a detailed report of a case with peripheral variant carcinosarcoma diagnosed by percutaneous needle biopsy under sonographic guidance. The clinical, pathologic and immunohistochemical hallmarks of this unique tumor are also reviewed.

Hydrochlorothiazide-induced pulmonary edema: a case report and literature review

A 67-year-old man developed non-cardiogenic pulmonary edema after taking a hydrochlorothiazide (HCTZ) tablet. The symptoms remitted following supportive treatment but recurred after rechallenge. Immunologic studies showed increased immunoglobulin E, negative lymphocyte transformation test when exposed to HCTZ, normal blood lymphocyte subpopulations and complement levels, and negative antinuclear antibodies. We reviewed 22 previous reported cases and emphasized that physicians should be aware of this rare but life-threatening reaction.

Anomalous systemic arterial supply to normal basilar segments of the lower lobe of the left lung

A 38-year-old man with an anomalous systemic arterial supply from the descending thoracic aorta to the normal basilar segments of the left lower lobe experienced symptoms of progressive exertional dyspnea. Although the pulmonary parenchyma was normal, there was no pulmonary arterial supply to the basilar segments of the left lower lobe. Left lower lobectomy was performed because of worsening left-to-left shunt. Aortography and pulmonary arteriography form the cornerstone for diagnosis, but a less invasive diagnostic method with less patient suffering is high-resolution computed tomography, which might replace bronchography for accurate evaluation of the distribution and patency of the bronchial tree and delineation of the characteristic "Medusa's hair"-like anomalous vascular supply penetrating into the nearly normal pulmonary parenchyma.