Content-Aware Delivery of Scalable Video in Network Coding Enabled Named Data Networks

In this work, we propose a novel network coding enabled NDN architecture for the delivery of scalable video. Our scheme utilizes network coding in order to address the problem that arises in the original NDN protocol, where optimal use of the bandwidth and caching resources necessitates the coordination of the forwarding decisions. To optimize the performance of the proposed network coding based NDN protocol and render it appropriate for transmission of scalable video, we devise a novel rate allocation algorithm that decides on the optimal rates of Interest messages sent by clients and intermediate nodes. This algorithm guarantees that the achieved flow of Data objects will maximize the average quality of the video delivered to the client population. To support the handling of Interest messages and Data objects when intermediate nodes perform network coding, we modify the standard NDN protocol and introduce the use of Bloom filters, which store efficiently additional information about the Interest messages and Data objects. The proposed architecture is evaluated for transmission of scalable video over PlanetLab topologies. The evaluation shows that the proposed scheme performs very close to the optimal performance

RC-NDN: Raptor Codes Enabled Named Data Networking

Information-centric networking (ICN) has been proposed to cope with the drawbacks of the Internet Protocol, namely scalability and security. The majority of research efforts in ICN have focused on routing and caching in wired networks, while little attention has been paid to optimizing the communication and caching efficiency in wireless networks. In this work, we study the application of Raptor codes to Named Data Networking (NDN), which is a popular ICN architecture, in order to minimize the number of transmitted messages and accelerate content retrieval times. We propose RC-NDN, which is a NDN compatible Raptor codes architecture. In contrast to other coding-based NDN solutions that employ network codes, RC-NDN considers security architectures inherent to NDN. Moreover, different from existing network coding based solutions for NDN, RC-NDN does not require significant computational resources, which renders it appropriate for low cost networks. We evaluate RC-NDN in mobile scenarios with high mobility. Evaluations show that RC-NDN outperforms the original NDN significantly. RC-NDN is particularly efficient in dense environments, where retrieval times can be reduced by 83% and the number of Data transmissions by 84.5% compared to NDN.

Capability of E-Bike Tourism in Switzerland

AIM OF PAPER AND RESEARCH QUESTIONS The primary aim of this investigation was to examine, if tourism in Switzerland can be stimulated by focusing on e-bike offers. Switzerland is an attractive and manifold country for bike tourism. However, there are plenty of hilly and steep areas, where the topography is quite demanding and cycling is predestined to ambitious sportsperson. Less performance-oriented bike tourists are possibly discouraged by the challenges of the landscape. E-bikes seem to be a reasonable alterna-tive to enable less trained person to attend bike tours in steeper regions as well as to keep heterogeneous groups together. E-bikes are already popular in Switzerland for daily routes as the journey to work, but they are not very common in the tour-istic context. The presented investigation evaluates the current standing of supply and demand for e-bike tourism and asks for opportunities and threats in the future development. LITERTURE REVIEW The existing frameworks to analyse capability in the field of sport tourism are limited, because of the broad variation of sports and tourism types. Still several conceptions are valuable to evaluate the opportunities of e-bike tourism in Switzer-land. According to Higham and Hinch (2009) the potential of touristic products and destinations always depends on the interaction among the factors place, people and activity. Standeven and de Knop (1999) support this position by identify-ing the experience of place as a key component of the sport tourism experience. Bull (2005) assumes that place not only affects experience. In his opinion, the specific spatially located resources are even crucial for the existence of nature sports. He identifies four factors determining the attraction of touristic products or destination, as physical characteristics, accessibility and infrastructural arrangements, political and economic resources as well as cultural and perceptual aspects. Concerning the demand side (people) the contemporary research is guided by an individual psychological focus delivering mainly results about motives and the decision making process (e.g. Görtz & Hürten, 2011). RESEARCH DESIGN AND DATA ANALYSIS The presented study is based on a between method triangulation, consisting of qualitative interviews with important stake-holders on the supply side and a cross sectional survey on the demand side. Qualitative interviews were conducted with the first provider of touristic e-bike routes and with the manager of the leading e-bike rental company in Switzerland. The interviews were evaluated by qualitative content analysis according to Mayring (2008). The survey covered a randomized sample of 748 adult persons and focused on interests and needs of potential consumers. The concluding potentials analy-sis combined the results of the interviews and the survey with the findings of literature research. As central outcome the strengths, weaknesses, opportunities and threats were evaluated and presented by SWOT-analysis. RESULTS Results showed that the development of e-bike tourism in Switzerland was not initiated by tourism promoter, but by an innovative e-bike producer. However, also for the manufacturer the fit between landscape (place), product (activity) and visitors (people) was the crucial criterion. The first e-bike tours were offered in a demanding and rural region, in order that the experience of place was able to promote a positive overall experience. Due to the success of the first touristic e-bike products, several tourism regions started to extend their portfolio with e-bike offers. To date a nationwide network for signalised e-bike tours, rental stations and changing stations for rechargeable batteries is established. Despite the attractive offer, the demand is only moderate. The obtained results of the consumer survey pointed at a certain barrier to use e-bikes for tourism activities. The most substantial barrier is the missing affinity for bike tourism in general. Another notable group considering themselves as “fit enough for normal bike tourism”. Nevertheless 55% of the respondent are interested in tour-istic e-bike products. Looking only at people with e-bike tourism experience, even 92% are interested in further activities. DISCUSSION AN CONCLUSION The current study findings are encouraging because they suggest a superior suitability and an attractive level of e-bike tourism products in Switzerland. The results of the consumer survey indicate an increasing demand for e-bike tourism. The investigation also points at some risks, as the rivalry for bike tourism or the raised safety hazard because of the increased driving speed. Summing up, the results support the conclusion, that e-bike tourism will become more important in the com-ing years. However, to reach the goal relevant trends as the requirement for customised offers must be considered and marketing activities are supposed to be extended. REFERENCES Bull, C. (2005). Sport tourism resource analysis. In J. Higham (Ed.), Sport tourism destination: Issues, opportunities and analysis (pp. 25-38). Amsterdam: Elsevier Butterworth-Heinemann. Görtz, M., & D. Hürten (2011). Motive der Radurlauber, psychografische Merkmale und Reiseverhalten. In A. Dreyer, E. Miglbauer & R. Mühlnickel (Hrsg.), Radtourismus. Entwicklungen, Potenziale, Perspektiven (S. 36-43). München: Olden-bourg. Higham, J., & Hinch, T. (2009). Sport and Tourism. Globalization, Mobility and Identity. Amsterdam: Butterworth-Heinemann. Mayring, P. (2008). Qualitative Inhaltsanalyse. Grundlagen und Techniken (10. Aufl.). Weinheim: Beltz Verlag. Standeven, J., & De Knop, P. (1999). Sport Tourism. Campaign: Human Kinetics.

Trajectory mapping of middle atmospheric water vapor by a mini network of NDACC instruments

The important task to observe the global coverage of middle atmospheric trace gases like water vapor or ozone usually is accomplished by satellites. Climate and atmospheric studies rely upon the knowledge of trace gas distributions throughout the stratosphere and mesosphere. Many of these gases are currently measured from satellites, but it is not clear whether this capability will be maintained in the future. This could lead to a significant knowledge gap of the state of the atmosphere. We explore the possibilities of mapping middle atmospheric water vapor in the Northern Hemisphere by using Lagrangian trajectory calculations and water vapor profile data from a small network of five ground-based microwave radiometers. Four of them are operated within the frame of NDACC (Network for the Detection of Atmospheric Composition Change). Keeping in mind that the instruments are based on different hardware and calibration setups, a height-dependent bias of the retrieved water vapor profiles has to be expected among the microwave radiometers. In order to correct and harmonize the different data sets, the Microwave Limb Sounder (MLS) on the Aura satellite is used to serve as a kind of traveling standard. A domain-averaging TM (trajectory mapping) method is applied which simplifies the subsequent validation of the quality of the trajectory-mapped water vapor distribution towards direct satellite observations. Trajectories are calculated forwards and backwards in time for up to 10 days using 6 hourly meteorological wind analysis fields. Overall, a total of four case studies of trajectory mapping in different meteorological regimes are discussed. One of the case studies takes place during a major sudden stratospheric warming (SSW) accompanied by the polar vortex breakdown; a second takes place after the reformation of stable circulation system. TM cases close to the fall equinox and June solstice event from the year 2012 complete the study, showing the high potential of a network of ground-based remote sensing instruments to synthesize hemispheric maps of water vapor.

Trajectory mapping of middle atmospheric water vapor by a mini network of NDACC instruments

The important task to observe the global coverage of middle atmospheric trace gases like water vapor or ozone usually is accomplished by satellites. Climate and atmospheric studies rely upon the knowledge of trace gas distributions throughout the stratosphere and mesosphere. Many of these gases are currently measured from satellites, but it is not clear whether this capability will be maintained in the future. This could lead to a significant knowledge gap of the state of the atmosphere. We explore the possibilities of mapping middle atmospheric water vapor in the Northern Hemisphere by using Lagrangian trajectory calculations and water vapor profile data from a small network of five ground-based microwave radiometers. Four of them are operated within the frame of NDACC (Network for the Detection of Atmospheric Composition Change). Keeping in mind that the instruments are based on different hardware and calibration setups, a height-dependent bias of the retrieved water vapor profiles has to be expected among the microwave radiometers. In order to correct and harmonize the different data sets, the Microwave Limb Sounder (MLS) on the Aura satellite is used to serve as a kind of traveling standard. A domain-averaging TM (trajectory mapping) method is applied which simplifies the subsequent validation of the quality of the trajectory-mapped water vapor distribution towards direct satellite observations. Trajectories are calculated forwards and backwards in time for up to 10 days using 6 hourly meteorological wind analysis fields. Overall, a total of four case studies of trajectory mapping in different meteorological regimes are discussed. One of the case studies takes place during a major sudden stratospheric warming (SSW) accompanied by the polar vortex breakdown; a second takes place after the reformation of stable circulation system. TM cases close to the fall equinox and June solstice event from the year 2012 complete the study, showing the high potential of a network of ground-based remote sensing instruments to synthesize hemispheric maps of water vapor.