Türk Telekom

About: Türk Telekom is a based out in . It is known for research contribution in the topics: Cellular network & Mobile computing. The organization has 80 authors who have published 144 publications receiving 3251 citations. The organization is also known as: Türk Telekomünikasyon A.Ş..

Smart Grid Technologies: Communication Technologies and Standards

Abstract: For 100 years, there has been no change in the basic structure of the electrical power grid. Experiences have shown that the hierarchical, centrally controlled grid of the 20th Century is ill-suited to the needs of the 21st Century. To address the challenges of the existing power grid, the new concept of smart grid has emerged. The smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability, and so on. While current power systems are based on a solid information and communication infrastructure, the new smart grid needs a different and much more complex one, as its dimension is much larger. This paper addresses critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues and opportunities. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as to discuss the still-open research issues in this field. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.

Big data caching for networking: moving from cloud to edge

Abstract: In order to cope with the relentless data tsunami in 5G wireless networks, current approaches such as acquiring new spectrum, deploying more BSs, and increasing nodes in mobile packet core networks are becoming ineffective in terms of scalability, cost, and flexibility. In this regard, context- aware 5G networks with edge/cloud computing and exploitation of big data analytics can yield significant gains for mobile operators. In this article, proactive content caching in 5G wireless networks is investigated in which a big-data-enabled architecture is proposed. In this practical architecture, a vast amount of data is harnessed for content popularity estimation, and strategic contents are cached at BSs to achieve higher user satisfaction and backhaul offloading. To validate the proposed solution, we consider a real-world case study where several hours worth of mobile data traffic is collected from a major telecom operator in Turkey, and big-data-enabled analysis is carried out, leveraging tools from machine learning. Based on the available information and storage capacity, numerical studies show that several gains are achieved in terms of both user satisfaction and backhaul offloading. For example, in the case of 16 BSs with 30 percent of content ratings and 13 GB storage size (78 percent of total library size), proactive caching yields 100 percent user satisfaction and offloads 98 percent of the backhaul.

Epidemiology of vitiligo, associated autoimmune diseases and audiological abnormalities: Ankara study of 80 patients in Turkey.

Abstract: Background Recent clinical studies suggest that the pathogenetic mechanisms of vitiligo could be of systemic origin as vitiligo is associated with auditory abnormalities as well as other autoimmune disorders. Objectives To investigate clinical, genetic characteristics and laboratory findings of vitiligo as well as auditory abnormalities and the association of the disease with the other autoimmune disorders. Materials and methods From January to December 2008, we collected-data from 80 vitiligo patients to establish the clinical and epidemiological profile of vitiligo in Turkey. Results Thirty patients were men and 50 were women, with a mean age of 37 years and a mean onset age of 10 years. Vitiligo vulgaris was the most common type, followed by focal, acrofacial, segmental and universal types. Forty-four (55%) patients had an associated autoimmune disease. These associated diseases were Hashimoto thyroiditis in 25, alopecia areata in 10, pernicious anaemia in seven and diabetes mellitus in two patients. Statistically significant changes in human leukocyte antigen in patients with vitiligo were HLA A24,-30, B63, CW6, DR15, DR51, DQ5,-6. Auditory problems were observed in 37.7% patients. Nine of the 20 patients showed unilateral minimal hearing loss (>30 dB), while the other 11 demonstrated bilateral hearing loss (>30 dB) over a large range of frequencies (2000–8000 Hz). Conclusion Our study demonstrates that vitiligo is a part of systemic autoimmune process. Audiological examination should be performed in all patients for auditory problems which are commonly presented as hypoacusis.

Public Procurement Auctions and Competition in Turkey

Abstract: This paper empirically investigates the effect of the competitive environment (number of participants) on the cost of procurement. We use a unique dataset provided by the Public Procurement Authority (PPA) of Turkey that covers all of the government procurement auctions for the years 2004–2006. First, after controlling for possible endogeneity, we show that the number of bidders significantly and negatively affects the procurement price. Thus, the existence of a more competitive environment significantly decreases procurement costs in Turkey. Second, when auctions are open to foreign participation, the auction price tends to be lower. Finally, prices in services and goods sectors are more sensitive to changes in the number of bidders than is true for the construction sector. The results of this paper have several policy implications for e-procurement and efficient procurement design.