This paper presents a design method of perfect tracking control for discrete-time systems based on multi-rate control. Generally, perfect tracking control schemes cannot be applied to nonminimum ...phase plants because of unstable pole-zero cancellations. Some methods that are applicable to nonminimum phase plants have been proposed, however, the following problems are left unsolved: limitations to plants and unclearness of design freedoms. We propose to use multi-rate control systems and state feedback schemes for perfect tracking. Since the method has been stated in 2-degree of freedom control techniques in this paper, it is clear how the design freedoms will be reserved after the design of tracking control. Basic techniques of this scheme have been presented, however, they cannot be applied to nonminimum phase discrete-time systems. We propose techniques that are applicable to nonminimum phase discrete time systems. Finally, computer simulation results are presented.
Classification results using texture analysis is presented for forest fire smoke from satellite remote sensing data. Texture analysis is carried out for normalized difference images calculated from ...visible and thermal infrared images of the Indonesian forest fire in 1997. Smoke regions are identified by assuming threshold values for the resulting texture feature as well as for radiances in the original and difference images. It is found that when the thresholds are chosen appropriately for GMS visible and infrared spin scan radiometer, 94% pixels exhibit agreement between the classification results using the texture analysis and the supervised Euclidean classification. Agreement is found for 96% pixels in mutual verification using the VISSR image and a concurrent NOAA advanced very high resolution radiometer image. A correlation coefficient of 0.91 is obtained between the results from the two sensors in the variation of the number of smoke pixels accumulated for 12 days in September 1997. Additionally, it is confirmed that as the threshold value of the texture feature is increased, the variation range of the aerosol optical thickness is also increased. As a whole, this study indicates that texture analysis provides quite reasonable results in the smoke detection when appropriately combined with the spectral information.
We studied 19 cases of Left Ventricular Free Wall Rupture (LVFWR) following acute myocardial infarction, admitted to our CCU between 1987 and 1996. We were able to treat 15 patients and diagnosed 4 ...cases as LVFWR at postmortem after sudden deaths. Of the treated 15 patients, 11 survived: 1 out of 2 repaired under cardiopulmonary bypass (CPB), 5 out of 7 repaired without CPB, and 5 out of 6 non-surgically treated. Although the survival rate for those able to be treated was 73%, overall rate was 58%. There were 7 cases of blow-out type: 4 of which were sudden deaths, and 3 were operated. Thoracotomy and direct closure of rupture without CPB was done at bed-side in 2 cases. Even though hemostasis was successful, they did not survive. The 3rd case survived with the patch closure under CPB. In this case, the circulation was maintained pre-operatively with the pericardial-central venous bypass drainage method. This method seems to be extremely effective in saving blow-out cases. There were 12 subacute patients. Although 2 cases were lost, total of 10 patients were saved, including 2 direct suture closures of rupture without CPB, 3 median sternotomy and fibrin-glue fixations, 1 where only pericardial drainage was done, and 4 in whom percutaneous intrapericardial fibrin-glue fixation therapy was utilized. Since the risk of secondary damage to the fragile infarcted are from direct suturing of ruptured myocardium exists in LVFWR, we changed to the Infarction Exclusion Technique under CPB during surgical repair, based on our experiences with ruptured intraventricular septum. In general, the only treatment believed to be available for LVFWR has been surgical. However, our experiences suggest that other treatments may also be effective. If the best suitable method could be chosen from various therapies, it may contribute to improving outcome statistics. The reduction of left ventricular pressure in the treatment is extremely important, being the key to improving survival rate.
This paper presents a new method for the self-tuning control of nonminimum phase discrete-time stochastic systems using approximate inverse systems obtained from the least-squares approximation. ...Using this approximate inverse system the gain response of the system can be made approximately unity and phase response exactly zero. This approximate inverse system can be used in the same manner for both minimum and nonminimum phase systems. Moreover, the order of the feedback controller does not depend upon the approximate inverse system. We just need an extra FIR filter in the feedforward path. There exists no unstable pole-zero cancellation in the system, but the effect of the unstable zeros can be cancelled approximately. Finally, several computer simulation results are presented to illustrate the effectiveness of the proposed method.
Design of generalized class E 2 dc/dc converter Sekiya, Hiroo; Lu, Jianming; Yahagi, Takashi
International journal of circuit theory and applications,
05/2003, Letnik:
31, Številka:
3
Journal Article
PDF
