For The Planning Purposes Modelling Of The Discontinuties In The Natural Stone Quarries

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2006Kaya mostralarında, şeritmetre ve jeolojik pusula kullanılarak toplanan veriler, süreksizliklerin rastgele dağıldığı ve dairesel olduğu kabul edilerek işlenir. Elde edilen istatistiksel verilere uygun rastgele çatlaklar üretilerek kaya kütlesinin görünmeyen bölümlerindeki çatlaklarla aynı istatistiki özelliklere sahip 3 boyutlu çatlak haritası elde edilir. Bu haritalar, mermer ve granit gibi doğal taş malzemelerinin üretiminin gerçekleştirildiği maden ocaklarındaki yapının değerlendirilmesinde kullanılır. Bu sayede ocak planlanması, üretilecek blok boyutlarının kestirilmesi, verimi ve tüm ocak faaliyetlerinin optimizasyonunun yapılması sağlanabilir. Bu çalışmanın amacı, söz konusu haritanın elde edilebilmesini sağlayacak bir yazılımın geliştirilmesi ve doğal taş madenlerinde uygulanabilir hale getirilmesidir.The data, which is collected from exposed rock faces by using a tape meter and a geologic compass, is processed with the acceptance of circular shape and randomness of discontinuities. Random fractures are produced by using the obtained statistical information. A 3D discontinuity map is drawn, which has the same statistical properties with the unexposed rock mass. This map is used to validate the structure of the quarries, where natural stones like marble and granite produced. This helps in planning the pits, assuming the dimensions of producible blocks, increasing efficiency and optimizing the mining applications. The aim of this work is to produce a software which is able to obtain this kind of map and make it applicable in natural stone quarries.Yüksek LisansM.Sc

E-Commerce and the Market Structure of Retail Industries

This article examines the effect of the advent and diffusion of e-commerce on supply-side industry structure. We specify a general industry model involving consumers with differing search costs buying products from heterogeneous producers. We interpret e-commerce as a reduction in consumers' search costs. We show how it reallocates market shares from high-cost to low-cost producers. We test the model using US data for three industries: travel agencies, bookstores and new car dealers. Each industry exhibits the market share shifts predicted by the model but the mechanisms vary, ranging from aggregate factors in the travel industry to local-market factors in the other two industries. Copyright � The Author(s). Journal compilation � Royal Economic Society 2009.