4 resultados para video on demand

em Dalarna University College Electronic Archive


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IPTV is now offered by several operators in Europe, US and Asia using broadcast video over private IP networks that are isolated from Internet. IPTV services rely ontransmission of live (real-time) video and/or stored video. Video on Demand (VoD)and Time-shifted TV are implemented by IP unicast and Broadcast TV (BTV) and Near video on demand are implemented by IP multicast. IPTV services require QoS guarantees and can tolerate no more than 10-6 packet loss probability, 200 ms delay, and 50 ms jitter. Low delay is essential for satisfactory trick mode performance(pause, resume,fast forward) for VoD, and fast channel change time for BTV. Internet Traffic Engineering (TE) is defined in RFC 3272 and involves both capacity management and traffic management. Capacity management includes capacityplanning, routing control, and resource management. Traffic management includes (1)nodal traffic control functions such as traffic conditioning, queue management, scheduling, and (2) other functions that regulate traffic flow through the network orthat arbitrate access to network resources. An IPTV network architecture includes multiple networks (core network, metronetwork, access network and home network) that connects devices (super head-end, video hub office, video serving office, home gateway, set-top box). Each IP router in the core and metro networks implements some queueing and packet scheduling mechanism at the output link controller. Popular schedulers in IP networks include Priority Queueing (PQ), Class-Based Weighted Fair Queueing (CBWFQ), and Low Latency Queueing (LLQ) which combines PQ and CBWFQ.The thesis analyzes several Packet Scheduling algorithms that can optimize the tradeoff between system capacity and end user performance for the traffic classes. Before in the simulator FIFO,PQ,GPS queueing methods were implemented inside. This thesis aims to implement the LLQ scheduler inside the simulator and to evaluate the performance of these packet schedulers. The simulator is provided by ErnstNordström and Simulator was built in Visual C++ 2008 environmentand tested and analyzed in MatLab 7.0 under windows VISTA.

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En grafisk designer måste kunna producera oavsett vilka förhållanden som råder. Rapporten behandlar vad korta och långa deadlines har för inverkan på denna förmåga och hur kreativiteten kan främjas vid stressiga situationer. Semistrukturerade djupintervjuer utfördes med åtta Art- och Creative directors i Gävledala-regionen för att undersöka hur de upplevde att vara kreativa under stressiga förhållanden. Resultatet visade att det generellt inte var ett problem för studiens respondenter att vara kreativa på beställning men att de inte heller följde några specifika metoder för att underlätta arbetsflödet. Det visade sig även att det snarare var arbetsbördan och mängden arbetsuppgifter som påverkade stressfaktorn än en specifik tidsram.

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Since 1980s, Western linguists and specialists on second language acquisition have emphasized the importance of enhancing students’ intercultural communication competence in foreign language education. At the same time, the demand for intercultural communicative competence increased along with the advances of communication technology with its increasingly global reach and the process of globalization itself.In the field of distance language education, these changes have resulted in a shift of focus from the production and distribution of learning materials towards communication and learning as a social process, facilitated by various internet-based platforms. The current focus on learners interacting and communicating synchronously trough videoconferencing is known as the fourth generation of distance language education. Despite the fact that teaching of Chinese as a foreign language (CFL) faces the same or even greater challenges as teaching other languages, the intercultural communication perspective is still quite a new trend in CFL and its implementation and evaluation are still under development. Moreover, the advocates of the new trends in CFL have so far focused almost exclusively on classroom-based courses, neglecting the distance mode of CFL and leaving it as an open field for others to explore. In this under-researched context, Dalarna University (Sweden), where I currently work, started to provide web-based courses of the Chinese language in 2007. Since 2010, the Chinese language courses have been available only in the distance form, using the same teaching materials as the previous campus-based courses. The textbooks used in both settings basically followed the functional nationalism approach. However, in order to catch up with the main trend of foreign-language education, we felt a need to implement the cross-cultural dimension into the distance courses as well. Therefore in 2010, a pilot study has been carried out to explore opportunities and challenges for implementing a cross-cultural perspective into existing courses and evaluating the effectiveness of this implementation based on the feedback of the students and on the experience of the teacher/researcher.

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Wooden railway sleeper inspections in Sweden are currently performed manually by a human operator; such inspections are based on visual analysis. Machine vision based approach has been done to emulate the visual abilities of human operator to enable automation of the process. Through this process bad sleepers are identified, and a spot is marked on it with specific color (blue in the current case) on the rail so that the maintenance operators are able to identify the spot and replace the sleeper. The motive of this thesis is to help the operators to identify those sleepers which are marked by color (spots), using an “Intelligent Vehicle” which is capable of running on the track. Capturing video while running on the track and segmenting the object of interest (spot) through this vehicle; we can automate this work and minimize the human intuitions. The video acquisition process depends on camera position and source light to obtain fine brightness in acquisition, we have tested 4 different types of combinations (camera position and source light) here to record the video and test the validity of proposed method. A sequence of real time rail frames are extracted from these videos and further processing (depending upon the data acquisition process) is done to identify the spots. After identification of spot each frame is divided in to 9 regions to know the particular region where the spot lies to avoid overlapping with noise, and so on. The proposed method will generate the information regarding in which region the spot lies, based on nine regions in each frame. From the generated results we have made some classification regarding data collection techniques, efficiency, time and speed. In this report, extensive experiments using image sequences from particular camera are reported and the experiments were done using intelligent vehicle as well as test vehicle and the results shows that we have achieved 95% success in identifying the spots when we use video as it is, in other method were we can skip some frames in pre-processing to increase the speed of video but the segmentation results we reduced to 85% and the time was very less compared to previous one. This shows the validity of proposed method in identification of spots lying on wooden railway sleepers where we can compromise between time and efficiency to get the desired result.