Gürel, G.

Article | 2001 | Dental clinics of North America45 ( 1 )

Dentistry has been witness to tremendous changes in technology, introducing new techniques and materials. New procedures are being performed faster, are more reliable, are painless, and are more esthetic. These changes not only have been extremely motivational for dentists, but also for patients. Patients are aware that esthetic approaches in dentistry can change one's appearance, and are coming to the dentist willingly.

Dogan, F | Civelek, A | Oktay, I

Conference Object | 2001 | JOURNAL OF DENTAL RESEARCH80 ( 4 ) , pp.1283 - 1283

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Erdal, Cevat | Toker, Ali | Acar, Cevdet

Article | 2001 | Istanbul University Journal of Electrical and Electronics Engineering1 ( 2 ) , pp.267 - 273

Süreç kontrol endüstrisinde, orantı-türev-integral (PID) tip kontrolörler en önemli kontrol elemanlarından biridir. Uygulamada, analog kontrolörlerde genellikle işlemsel kuvvetlendiriciler kullanılmaktadır. Öte yandan ikinci nesil akım tasıyıcı ve akım geri beslemeli işlemsel kuvvetlendiriciler gibi akım çıkıslı olarak çalısan devreler, islemsel kuvvetlendiricilerle karşılaştırıldıklarında daha geniş bir frekans bandına, daha düşük güç tüketimi ile çalışma, ve daha iyi doğrusallık ve kararlılık özelliklerine sahip olduklarından, son zamanlarda oldukça çok dikkat çekmektedirler. Bu çalışmanın amacı akım tasıyıcılar (CCII) kullanarak . . .bir analog kontrolör gerçeklemek için gerekli tasarım yöntemini vermektir. Tasarımı yapılan PID devresi için optimum parametre toleransları hesaplanmıştır. Bu toleranslar önerilen PID kontrol edicinin duyarlık davranışlarının iyileştirilmesi ve kontrol edilmesinde kullanılabilirler. In process control industry, the proportional-integral-derivative (PID) controllers are one of the most important control elements. In practice, operational amplifiers are generally used in analog controllers. On the other hand, current-mode (CM) circuits such as second-generation current conveyors (CCII) and current feedback operational amplifiers (CFOA) have considerable attention due to their wider frequency band, lower power consumption, better linearity and stability properties compared to their voltage-mode counterparts, operational amplifiers. The purpose of this study is to present a synthesis procedure for the realization of analog PID controller by the use of CCIIs. For the designed PID circuit, the optimum parameter tolerances are determined. These tolerances can be used to improve and to control the sensitivity performance of the proposed PID controller Daha fazlası Daha az

Özdamar, L. | Demirhan, M.

Article | 2001 | Fuzzy Sets and Systems117 ( 1 ) , pp.47 - 60

An adaptive partitioning algorithm with random search is proposed to locate the global optimum of multimodal functions. Partitioning algorithms divide the feasible region into nonoverlapping partitions in order to restrict and direct the search to the most promising region expected to contain the global optimum. In such a scheme a partition evaluation measure is required to assess sub-regions in order to re-partition the most promising sub-region and intensify the search within that area. This study provides computational results on several classes of partition evaluation measures used in the assessment of samples taken from all par . . .titions. Among the partition evaluation classes used in our comparison are fuzzy, statistical, and deterministic interval estimation measures. Performance in terms of solution quality is reported on an extensive set of 77 test functions collected from the literature Daha fazlası Daha az

Kaptan, RFU | Yircali, UA

Conference Object | 2001 | JOURNAL OF DENTAL RESEARCH80 ( 4 ) , pp.1287 - 1287

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Uçan, Osman N. | Osman, Onur | Gümüş, Aykal

Article | 2001 | Istanbul University Journal of Electrical and Electronics Engineering1 ( 2 ) , pp.149 - 168

In this paper, the performance of turbo coded signals are investigated over a new channel model, denoted as 1 ± Dn / Partial Response Fading Channels (PRFC) with imperfect phase reference. The combined effects of the 1 ± Dn /PRFC and nonideal coherent receiver on the phase of the received amplitude and of a noisy carrier reference are considered, each modelled by the Rician and Tikhonov distributions respectively. As an example, the jitter performance of turbo coded signals are evaluated over 1D / PRSC channel with different fading parameter K, effective signalto-noise ratio in the carrier tracking loop a, iteration nu . . .mber and data block size N. The numerical results clearly demonstrate the error performance degradation due to both amplitude fading and phase noise process Daha fazlası Daha az

Demirhan, M. | Özdamar, L.

Article | 2001 | IEEE Transactions on Systems, Man and Cybernetics Part C: Applications and Reviews31 ( 3 ) , pp.344 - 351

The site characterization issue is the most essential task to be undertaken prior to the reclamation of a potentially contaminated site and it is composed of sampling, laboratory analysis, and data evaluation phases. We are primarily concerned with the data evaluation phase and we utilize a recently developed adaptive areal partitioning algorithm to characterize the site. Here, we enhance this approach by integrating expert knowledge (expert belief) into the fuzzy areal assessment scheme which derives information from sample data. We propose to allocate an adaptive weight to expert belief during the assessment. We compare the belief . . .-integrated approach with the nonintegrated one on synthetically generated sites where both uniform and biased sampling have been applied independently. In biased sampling, the zones claimed to be highly contaminated (by the expert) are allocated a higher sampling density. We demonstrate that the belief-integrated approach outperforms the nonintegrated one both when the expert is correct or mistaken in his/her judgment irrespective of the sampling methodology Daha fazlası Daha az

Bayrakçeken, Fuat | Jomehri, B.B. | Yaman, A.

Article | 2001 | Journal of the Indian Chemical Society78 ( 5 ) , pp.234 - 236

A number of photophysical properties of 5H-dibenzo[a,d]cycloheptene have been measured including the decay parameters of the lowest excited singlet and triplet states. Molecules were excited in a two-step process. In the first step, S1 is created which undergoes intersystem crossing to T1, then T-T absorption creates an excited triplet molecule which returns to the first excited singlet level by intersystem crossing. The recreated first excited singlet state decays back to the ground state by emitting B-type of delayed fluorescence.

Isitmangil, T. | Isitmangil, G. | Budak, Y. | Aydilek, R. | Celenk, M.K.

Article | 2001 | BMC Pulmonary Medicine1 , pp.234 - 236

Background: It is known that tissue and serum sialic acid levels may be altered by malignant transformation. In this study, sialic acid levels were determined in bronchoalveolar lavage fluid (BAL) and serum in two groups of patients with lung cancer and non-malignant diseases of the lung. Methods: Colorimetric methods were used for determination sialic acid in serum and in BAL samples. Flexible bronchoscopy was used to obtain the latter. Results: Sialic acid levels in bronchoalveolar lavage fluid and serum did not show any statistically significant difference between subjects with malignant and the non-malignant lung diseases (p > 0 . . ..05). Sialic acid levels were also unrelated to the stage and localization of the tumor (p > 0.05). Conclusions: Sialic acid levels do not appear to be a good marker for discriminating malignant from non-malignant diseases of the lung. © 2001 Isitmangil et al; licensee BioMed Central Ltd Daha fazlası Daha az

Bayrakçeken, Fuat | Yaman, A.

Article | 2001 | Journal of the Indian Chemical Society78 ( 6 ) , pp.298 - 300

Absorption, emission and some excited state lifetimes are measured at room temperature and at 77 K in solution. B-Type delayed fluorescence decay time is reported for the first time for triptycene. The results are compared with the findings of photolysis, flash photolysis and laser flash photolysis experiments.

Onbaşoglu, E. | Özdamar, L.

Article | 2001 | Journal of Global Optimization19 ( 1 ) , pp.27 - 50

Global optimization involves the difficult task of the identification of global extremities of mathematical functions. Such problems are often encountered in practice in various fields, e.g., molecular biology, physics, industrial chemistry. In this work, we develop five different parallel Simulated Annealing (SA) algorithms and compare them on an extensive test bed used previously for the assessment of various solution approaches in global optimization. The parallel SA algorithms consist of various categories: the asynchronous approach where no information is exchanged among parallel runs and the synchronous approaches where soluti . . .ons are exchanged using genetic operators, or where solutions are transmitted only occasionally, or where highly coupled synchronization is achieved at every iteration. One of these approaches, which occasionally applies partial information exchanges (controlled in terms of solution quality), provides particularly notable results for functions with vast search spaces of up to 400 dimensions. Previous attempts with other approaches, such as sequential SA, adaptive partitioning algorithms and clustering algorithms, to identify the global optima of these functions have failed without exception Daha fazlası Daha az

S. Özoguz | C. Acar | A. Toker | E.O. Güneş

Article | 2001 | IEE Proceedings: Circuits, Devices and Systems148 ( 3 ) , pp.115 - 120

Two transformation methods for obtaining new topologies from a given current-mode CCII filter are presented. These topologies realise the same transfer function as the initial filter for ideal CCIIs, but they can be derived in such a way that their active sensitivity with respect to a particular active parameter becomes zero. In this way, from a filter suffering from large active sensitivities, one may systematically obtain new filters with better active sensitivities.