Linear Quadratic Optimal Control of an Inverted Pendulum on a Cart using Artificial Bee Colony Algorithm: An Experimental Study

Bu çalışmada, Lineer Kuadratik Regülatör (LQR) ile bir ters sarkacın kontrolü için, Yapay Arı Kolonisi (ABC) optimizasyon algoritmasına dayalı bir metot önerilmiştir. LQR'ın temel tasarım parametreleri ağırlık matrisleridir. Ağırlık matrislerinin değerleri ile yüzde aşımı, yerleşme zamanı ve kararlı hal hatası gibi zaman uzayı performans kriterleri arasında doğrudan bir ilişki olmadığı için bu matrislerin seçimi genellikle deneme yanılma yöntemiyle gerçekleştirilmektedir. Bu çalışmada arabalı ters sarkaç ve bu mekanizmayı hareket ettiren DC motorun matematiksel modellerinin elde edilmesinin ardından sürü zekası temelli bir optimizasyon algoritması olan ABC algoritması kullanılarak bir LQR kontrolör tasarlanmıştır. Karşılaştırma ve deney sonuçları, ABC algoritmasının literatürde önerilen bir yöntem ile karşılaştırıldığında ağırlık matrislerinin belirlenmesinde daha etkin bir yol olduğunu göstermiştirThis study presents a Linear Quadratic Optimal (LQR) controller design for an inverted pendulum on a cart using the Artificial Bee Colony (ABC) algorithm. Main design parameters of the linear quadratic regulator are the weighting matrices. Generally, selecting weighting matrices is managed by trial and error since there exists no apparent connection between these weights and time domain requirements such as settling time, steady state error, and overshoot percentage. In this study after deriving the mathematical models of the inverted pendulum on a cart and the DC motor, an LQR controller is designed using the ABC algorithm to determine weighting matrices to overcome LQR design difficulties. The comparison and experimental results justify that the ABC algorithm is a very efficient way to determine LQR weighting matrices in comparison with a method in literatur

Turkey: How to deal with threats to journalism?

Go to the full book to find a version of this chapter tagged for accessibility

Barış medyası olarak alternatif medyalar ya da alternatif medyanın barış ile imtihanı

Çoban, Barış (Dogus Author) -- Conference full title: (Re)Making and Undoing of Peace/Conflict: 3th International Conference in Communication and Media Studies, North Cyprus: Eastern Mediterranean University, 2012

Counter-surveillance and alternative new media in Turkey

Ataman, Bora (Dogus Author) -- Çoban, Barış (Dogus Author)This study, drawing on alternative media and networked social movements, explores the counter-surveillance practices and oppositional imaginaries of activist citizen journalists (ACJs) in Turkey to combat the surveillance strategies of the authoritarian Turkish government. After the failed coup attempt in July 2016, the ruling party has become more suspicious of dissent of any kind. However, the ACJs who use mobile communication and social media as channels for journalism and counter-surveillance continue their critical journalistic work in this context. Using ethnographic data collected from interviews with these media activists, this study focuses on oppositional imaginaries regarding the surveillance culture as well as counter-surveillance tactics, both offensive and defensive. To do so, we conducted 22 in-depth interviews with the representatives of alternative new media (ANM) initiatives and ACJs who were gathering, producing and disseminating news at the time of the study (between January and July 2017). Backed by the available literature on interdisciplinary approaches, data were gathered from the interviews, thematically coded and critically analysed. The whole process of news-making that criticises the authoritarian surveillance state stands out as an offensive tactic. On the other hand, defensive tactics are very closely related to the safety of journalists, their sources and data. The paper argues that the variety of offensive and defensive tactics should be increased and they should be substantially improved. The study also sheds light on the need for more detailed and extensive interdisciplinary research

The user as producer in alternative media? The case of the Independent Communication Network (BIA).

This article focuses on the Independent Communication Network (BIA) as an instance of alternative media in Turkey. Throughout the study we define "alternative" media as non-dominant, counter-hegemonic media that prioritizes its distinct relationship with its audience. We report research based on in-depth interviews with the producers of the network's online site "BIANET news" combined with focus group studies with communication students and women activists that are identified as the main audience segments of BIANET news by the newsmakers. By focusing on the agents of both production and reception, this research enables us to examine participation and its form at both ends and to expound the problems of the conditions under which the user/audience can become the producer in Turkey

Mineral composition in cognate inclusions in Late Miocene-Early Pliocene potassic lamprophyres with affinities to lamproites from the Denizli region, Western Anatolia, Turkey: Implications for uppermost mantle processes in a back-arc setting

Mineral assemblages of both cognate inclusions and host-lamprophyres with lamproitic affinity in Kocapinar district (Denizli), Western Anatolia, consist of phlogopitic mica, diopsidic clinopyroxene, K-feldspar, apatite, opaque and carbonates (calcite-dolomite). Two distinct types of cognate inclusions have been defined in host lamprophyres: clinopyroxene-rich (CCI) and clinopyroxene-phlogopite-rich (CPCI). Whole-rock compositions of inclusions show a near-primitive nature with high MgO (7.56-15.1wt.%), Cr (195-2270ppm), Ni (213-335ppm) contents and a potassic character [K 2O (2.0-2.8wt.%)>Na 2O (0.4-2.2wt.%)]. Data imply that the inclusions crystallized from magmas formed by melting of phlogopite-bearing pyroxenites in a peridotitic mantle source, however, the presence of reverse-zoning in clinopyroxenes with salitic Fe-rich green cores in host-lamprophyres and CPCI inclusions suggest that the Denizli lavas represent mixtures of distinct (probably ultrapotassic and alkali basaltic) magmas. Estimated geobarometric constraints inferred from clinopyroxene compositions in CCI and CPCI inclusions indicate moderate pressures of pyroxene crystallization (ranging between 1.7 and 2.2GPa and corresponding to 53-70km depths) under low pressure magma fractionation. Results reveal that i) the origin of Denizli lamprophyres with transitional (between arc-type and intra-plate-type) geochemical signatures is consistent with a shallow level mantle petrogenesis, rather than a deep-seated origin related to mantle convection, ii) the source was a highly refractory and metasomatized peridotitic mantle present at the base of the lower crust, iii) metasomatic agents that affected the mantle lithosphere beneath Denizli region are distinct from those beneath other western Anatolia orogenic centers, and iv) the transitional character of Kocapinar (Denizli) lamprophyric rocks were probably formed as a result of either underplating or contamination of asthenospheric magma at the base of the mantle lithosphere, or assimilation of delaminated continental edge-lithospheric mantle via ascending asthenosphere. Denizli lamprophyres are interpreted to have formed during the formation of a basin/graben structure in the Latest Miocene-Early Pliocene, just after Late Miocene exhumation of Menderes massif. © 2012 Elsevier B.V