3,007 research outputs found
Assessment of First Comer Advantages and Network Effects; the Case of Turkish GSM Market
First comer advantages and network effects are frequently stated as among the most important determinants of market structures and this is particularly relevant for network economies including telecommunications markets. Connected to this, regulatory tools such as number portability have frequently been used to reduce market imperfections resulting from these effects. Within this context, this paper aims to analyze the role of these factors in creating the current market structure of Turkish GSM sector. By examining relevant data such as development of market shares in a historical perspective and by making use of consumer surveys, it is concluded that the dominant operator has benefited from being first comer in the market and established a stable market share (power) due to network effects that are used by this firm deliberately to entrench its position especially in the form of switching costs, scale economies, brand image and tariff (on-net vs. off-net pricing) differentiation; however, it is also observed that introduction of number portability lead to reduction in switching costs, increasing market competition. --First comer advantages,Network effects,Mobile telephony (GSM),number portability,Competition,Regulation and Consumer preferences
Survey of Transportation of Adaptive Multimedia Streaming service in Internet
[DE] World Wide Web is the greatest boon towards the technological advancement of modern era. Using the benefits of Internet globally, anywhere and anytime, users can avail the benefits of accessing live and on demand video services. The streaming media systems such as YouTube, Netflix, and Apple Music are reining the multimedia world with frequent popularity among users. A key concern of quality perceived for video streaming applications over Internet is the Quality of Experience (QoE) that users go through. Due to changing network conditions, bit rate and initial delay and the multimedia file freezes or provide poor video quality to the end users, researchers across industry and academia are explored HTTP Adaptive Streaming (HAS), which split the video content into multiple segments and offer the clients at varying qualities. The video player at the client side plays a vital role in buffer management and choosing the appropriate bit rate for each such segment of video to be transmitted. A higher bit rate transmitted video pauses in between whereas, a lower bit rate video lacks in quality, requiring a tradeoff between them. The need of the hour was to adaptively varying the bit rate and video quality to match the transmission media conditions. Further, The main aim of this paper is to give an overview on the state of the art HAS techniques across multimedia and networking domains. A detailed survey was conducted to analyze challenges and solutions in adaptive streaming algorithms, QoE, network protocols, buffering and etc. It also focuses on various challenges on QoE influence factors in a fluctuating network condition, which are often ignored in present HAS methodologies. Furthermore, this survey will enable network and multimedia researchers a fair amount of understanding about the latest happenings of adaptive streaming and the necessary improvements that can be incorporated in future developments.Abdullah, MTA.; Lloret, J.; Canovas Solbes, A.; GarcĂa-GarcĂa, L. (2017). Survey of Transportation of Adaptive Multimedia Streaming service in Internet. Network Protocols and Algorithms. 9(1-2):85-125. doi:10.5296/npa.v9i1-2.12412S8512591-
On the Evolutionary Co-Adaptation of Morphology and Distributed Neural Controllers in Adaptive Agents
The attempt to evolve complete embodied and situated artiïŹcial creatures in which
both morphological and control characteristics are adapted during the evolutionary
process has been and still represents a long term goal key for the artiïŹcial life and
the evolutionary robotics community.
Loosely inspired by ancient biological organisms which are not provided with a
central nervous system and by simple organisms such as stick insects, this thesis
proposes a new genotype encoding which allows development and evolution of mor-
phology and neural controller in artiïŹcial agents provided with a distributed neural
network.
In order to understand if this kind of network is appropriate for the evolution of
non trivial behaviours in artiïŹcial agents, two experiments (description and results
will be shown in chapter 3) in which evolution was applied only to the controllerâs
parameters were performed.
The results obtained in the ïŹrst experiment demonstrated how distributed neural
networks can achieve a good level of organization by synchronizing the output of
oscillatory elements exploiting acceleration/deceleration mechanisms based on local
interactions.
In the second experiment few variants on the topology of neural architecture were
introduced. Results showed how this new control system was able to coordinate the
legs of a simulated hexapod robot on two diïŹerent gaits on the basis of the external
circumstances.
After this preliminary and successful investigation, a new genotype encoding able to
develop and evolve artiïŹcial agents with no ïŹxed morphology and with a distributed
neural controller was proposed. A second set of experiments was thus performed
and the results obtained conïŹrmed both the eïŹectiveness of genotype encoding and
the ability of distributed neural network to perform the given task.
The results have also shown the strength of genotype both in generating a wide
range of diïŹerent morphological structures and in favouring a direct co-adaptation
between neural controller and morphology during the evolutionary process.
Furthermore the simplicity of the proposed model has showed the eïŹective role of
speciïŹc elements in evolutionary experiments. In particular it has demonstrated the
importance of the environment and its complexity in evolving non-trivial behaviours
and also how adding an independent component to the ïŹtness function could help
the evolutionary process exploring a larger space solutions avoiding a premature
convergence towards suboptimal solutions
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