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Gazi V.,Istanbul Kemerburgaz University
2012 IEEE Multi-Conference on Systems and Control, MSC 2012 | Year: 2012

In this article we analyze the stability of the particle dynamics in the Particle Swarm Optimization algorithm using tools from the nonlinear control systems literature including positive realness and stability of stochastic systems. © 2012 IEEE.

Fidan B.,University of Waterloo | Gazi V.,Istanbul Kemerburgaz University | Zhai S.,WISDRI Engineering and Research Incorporation Ltd Company | Cen N.,Ningbo Ulica Solar Science and Technology Co. | Karatas E.,Eti Makine Sanayi Ve Ticaret A. S.
IEEE Transactions on Industrial Electronics | Year: 2013

This paper presents a practical formation motion control scheme for robotic swarms based on single-view distance estimation, which is performed using a single nonsophisticated camera on each robot agent, and the prior information about the heights of the robots and other objects in the environment. Here, a nonsophisticated camera means one that has limited field of view and limited resolution. First, the vision mechanism is analyzed, and a single-view distance estimation scheme is designed. Then, a set of decentralized control laws, to be incorporated with distance estimation scheme, is introduced to move the robotic swarm in formation from an arbitrary initial position to an arbitrary final position without deforming the formation shape. The robots do not have any global positioning sensors, and they do not communicate with each other. The stability and performance of the overall system are analyzed mathematically. Later, practical issues are discussed regarding the proposed scheme, and the effects of delay and quantization in distance estimation are formally analyzed. Finally, we present experimental results demonstrating the performance of the proposed control scheme in real time. © 1982-2012 IEEE.

Vakifahmetoglu C.,Istanbul Kemerburgaz University
Ceramics International | Year: 2014

Macrocellular calcium silicate (wollastonite) ceramic foams possessing ∼86 vol% total porosity were produced from commercial calcium silicate hydrate (xonotlite) nano-size acicular crystals and poly-methyl-methacrylate microbeads (PMMA) (used as sacrificial pore formers). Open cell wollastonite foams had a bi-modal pore size distribution with major modes located ∼100 nm due to interparticle porosity and ∼100 μm due to the sacrificial pore former. These macrocellular ceramics were then used as a scaffold for MFI type zeolite (silicalite-1) synthesis. Monolayer coffin shaped zeolite crystals (∼3 μm size, measured from the c-axis and ∼300 nm thickness) were observed with almost full coverage on the inner macro-cell walls. The specific surface area of the components increased from 9.6 m2/g to 108.2 m2/g via zeolite functionalization, leading to components possessing multiscale porosity. © 2014 Elsevier Ltd and Techna Group S.r.l.

Cifter A.,Istanbul Kemerburgaz University
Electric Power Systems Research | Year: 2013

In this paper, electricity price behavior in the Nordic electric power market is forecasted with both the Markov-switching generalized autoregressive conditional heteroskedasticity (MS-GARCH) model and a set of different volatility models. The MS-GARCH model is estimated with two regimes, representing periods of low and high volatility. This study shows that electricity price volatility is not only highly volatile but also strongly regime-dependent. The empirical results show that the MS-GARCH model enables more accurate forecasting than the standard GARCH models, according to tail loss and reality check tests for one- and multi-step ahead forecasts. The results suggest that both the electricity generation companies and consumers of electricity could carry out better price forecasts by using the proposed MS-GARCH model. © 2013 Elsevier B.V. All rights reserved.

Adiguzel Y.,Istanbul Kemerburgaz University | Kulah H.,Middle East Technical University | Kulah H.,Universiteler Mah
Biosensors and Bioelectronics | Year: 2015

The scope of the applications of breath sensors is abundant in disease diagnosis. Lung cancer diagnosis is a well-fitting health-related application of this technology, which is of utmost importance in the health sector, because lung cancer has the highest death rate among all cancer types, and it brings a high yearly global burden. The aim of this review is first to provide a rational basis for the development of breath sensors for lung cancer diagnostics from a historical perspective, which will facilitate the transfer of the idea into the rapidly evolving sensors field. Following examples with diagnostic applications include colorimetric, composite, carbon nanotube, gold nanoparticle-based, and surface acoustic wave sensor arrays. These select sensor applications are widened by the state-of-the-art developments in the sensors field. Coping with sampling sourced artifacts and cancer staging are among the debated topics, along with the other concerns like proteomics approaches and biomimetic media utilization, feature selection for data classification, and commercialization. © 2014 Elsevier B.V.

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