6,587 research outputs found

    An assessment of supply chain and innovation management practices in the manufacturing industries in Turkey

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    This paper aims at assessing the supply chain and innovation management in the manufacturing industries in Turkey on an empirical basis. The assessments presented are based on parts of the data and information collected through the execution of the Competitive Strategies and Best Practices Benchmarking Questionnaire in 82 companies from four sectors of the manufacturing industries in Turkey. Results of these sectoral benchmarking studies reported elsewhere indicate the need of adopting product differentiation particularly through more knowledge intensive products as the dominant competitive strategy and also the need for improvement in various areas of supply chain as well as innovation management. In this paper, these issues are analysed through the survey results and some conclusions are drawn. Several policy measures applicable in near future are suggested for improving the areas found in need of improvement

    Competitive manufacturing strategies for the manufacturing industries in Turkey

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    In this study, results of the research into competitive manufacturing strategies of companies in four different sector studies covering 82 companies from the electronics, cement, automotive manufacturers, and appliances part and component suppliers in Turkey are presented. The data used in the study are gathered by conducting four sector surveys in 1997 and 1998 using a questionnaire supported by some follow-up interviews and site visits. A competitive manufacturing strategy is represented here by its components being the competitive priorities, the manufacturing objectives, and the action plans the companies plan to adopt in the near future. The results indicate that the manufacturing industry in Turkey bases its competition strategy mainly on low price, although there is a growing trend towards increasing emphasis on product differentiation. Quality and quality related issues constitute the top priority issues for the manufacturing industries in Turkey with Total Quality Management being the most preferred action plan

    Eco-nostalgia in Popular Turkish Cinema

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    Book Summary: Ecomedia: Key Issues is a comprehensive textbook introducing the burgeoning field of ecomedia studies to provide an overview of the interface between environmental issues and the media globally. Linking the world of media production, distribution, and consumption to environmental understandings, the book addresses ecological meanings encoded in media texts, the environmental impacts of media production, and the relationships between media and cultural perceptions of the environment. [From the publisher

    Distortion Exponent in MIMO Fading Channels with Time-Varying Source Side Information

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    Transmission of a Gaussian source over a time-varying multiple-input multiple-output (MIMO) channel is studied under strict delay constraints. Availability of a correlated side information at the receiver is assumed, whose quality, i.e., correlation with the source signal, also varies over time. A block-fading model is considered for the states of the time-varying channel and the time-varying side information; and perfect state information at the receiver is assumed, while the transmitter knows only the statistics. The high SNR performance, characterized by the \textit{distortion exponent}, is studied for this joint source-channel coding problem. An upper bound is derived and compared with lowers based on list decoding, hybrid digital-analog transmission, as well as multi-layer schemes which transmit successive refinements of the source, relying on progressive and superposed transmission with list decoding. The optimal distortion exponent is characterized for the single-input multiple-output (SIMO) and multiple-input single-output (MISO) scenarios by showing that the distortion exponent achieved by multi-layer superpositon encoding with joint decoding meets the proposed upper bound. In the MIMO scenario, the optimal distortion exponent is characterized in the low bandwidth ratio regime, and it is shown that the multi-layer superposition encoding performs very close to the upper bound in the high bandwidth expansion regime.Comment: Submitted to IEEE Transactions on Information Theor

    Capacity of a Class of State-Dependent Orthogonal Relay Channels

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    The class of orthogonal relay channels in which the orthogonal channels connecting the source terminal to the relay and the destination, and the relay to the destination, depend on a state sequence, is considered. It is assumed that the state sequence is fully known at the destination while it is not known at the source or the relay. The capacity of this class of relay channels is characterized, and shown to be achieved by the partial decode-compress-and-forward (pDCF) scheme. Then the capacity of certain binary and Gaussian state-dependent orthogonal relay channels are studied in detail, and it is shown that the compress-and-forward (CF) and partial-decode-and-forward (pDF) schemes are suboptimal in general. To the best of our knowledge, this is the first single relay channel model for which the capacity is achieved by pDCF, while pDF and CF schemes are both suboptimal. Furthermore, it is shown that the capacity of the considered class of state-dependent orthogonal relay channels is in general below the cut-set bound. The conditions under which pDF or CF suffices to meet the cut-set bound, and hence, achieve the capacity, are also derived.Comment: This paper has been accepted by IEEE Transactions on Information Theor

    Joint Source-Channel Coding with Time-Varying Channel and Side-Information

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    Transmission of a Gaussian source over a time-varying Gaussian channel is studied in the presence of time-varying correlated side information at the receiver. A block fading model is considered for both the channel and the side information, whose states are assumed to be known only at the receiver. The optimality of separate source and channel coding in terms of average end-to-end distortion is shown when the channel is static while the side information state follows a discrete or a continuous and quasiconcave distribution. When both the channel and side information states are time-varying, separate source and channel coding is suboptimal in general. A partially informed encoder lower bound is studied by providing the channel state information to the encoder. Several achievable transmission schemes are proposed based on uncoded transmission, separate source and channel coding, joint decoding as well as hybrid digital-analog transmission. Uncoded transmission is shown to be optimal for a class of continuous and quasiconcave side information state distributions, while the channel gain may have an arbitrary distribution. To the best of our knowledge, this is the first example in which the uncoded transmission achieves the optimal performance thanks to the time-varying nature of the states, while it is suboptimal in the static version of the same problem. Then, the optimal \emph{distortion exponent}, that quantifies the exponential decay rate of the expected distortion in the high SNR regime, is characterized for Nakagami distributed channel and side information states, and it is shown to be achieved by hybrid digital-analog and joint decoding schemes in certain cases, illustrating the suboptimality of pure digital or analog transmission in general.Comment: Submitted to IEEE Transactions on Information Theor

    A Learning Theoretic Approach to Energy Harvesting Communication System Optimization

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    A point-to-point wireless communication system in which the transmitter is equipped with an energy harvesting device and a rechargeable battery, is studied. Both the energy and the data arrivals at the transmitter are modeled as Markov processes. Delay-limited communication is considered assuming that the underlying channel is block fading with memory, and the instantaneous channel state information is available at both the transmitter and the receiver. The expected total transmitted data during the transmitter's activation time is maximized under three different sets of assumptions regarding the information available at the transmitter about the underlying stochastic processes. A learning theoretic approach is introduced, which does not assume any a priori information on the Markov processes governing the communication system. In addition, online and offline optimization problems are studied for the same setting. Full statistical knowledge and causal information on the realizations of the underlying stochastic processes are assumed in the online optimization problem, while the offline optimization problem assumes non-causal knowledge of the realizations in advance. Comparing the optimal solutions in all three frameworks, the performance loss due to the lack of the transmitter's information regarding the behaviors of the underlying Markov processes is quantified

    Effects of innovation diffusion on the development level for some European regions in the expansion period of the European Union

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    It is argued that innovation diffusion, in other words the movement of the new ideas or articrafts within an area over a number of time periods could become widespread once introduced in the area. After Schumpeter the role of the innovator has been significant as the inventor, as the developer or as the promoter. It is clear now that a number of economists have one thing in common that profit rates would be pushed to minimal levels in the absence of technical development. In fact, in the new theories of development concepts related to knowledge development and its diffusion take precedence. Moreover, concerning regional disparities and regional convergence issues in the European Union, it is pointed out that R&D investment in lagging areas could be the only way to avoid technology and development divergence between core and periphery. In this connection, it might be worthwhile to consider the enlargement process of the European Union with further expansion period. In this way, the objective of this article will be to find out probable effects of R&D on the development level in a five-years period (1996-2001) in order to examine the efficiency rate of innovation diffusion on the development level and to derive some theoretical and practical results.

    Source-Channel Coding Theorems for the Multiple-Access Relay Channel

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    We study reliable transmission of arbitrarily correlated sources over multiple-access relay channels (MARCs) and multiple-access broadcast relay channels (MABRCs). In MARCs only the destination is interested in reconstructing the sources, while in MABRCs both the relay and the destination want to reconstruct them. In addition to arbitrary correlation among the source signals at the users, both the relay and the destination have side information correlated with the source signals. Our objective is to determine whether a given pair of sources can be losslessly transmitted to the destination for a given number of channel symbols per source sample, defined as the source-channel rate. Sufficient conditions for reliable communication based on operational separation, as well as necessary conditions on the achievable source-channel rates are characterized. Since operational separation is generally not optimal for MARCs and MABRCs, sufficient conditions for reliable communication using joint source-channel coding schemes based on a combination of the correlation preserving mapping technique with Slepian-Wolf source coding are also derived. For correlated sources transmitted over fading Gaussian MARCs and MABRCs, we present conditions under which separation (i.e., separate and stand-alone source and channel codes) is optimal. This is the first time optimality of separation is proved for MARCs and MABRCs.Comment: Accepted to IEEE Transaction on Information Theor
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