http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2009/486465.htmlA system for retrieving video sequences created by tracking humans in a smart environment, by using spatial queries, is presented. Sketches made with a pointing device on the floor layout of the environment are used to form queries corresponding to locomotion patterns. The sketches are analyzed to identify the type of the query. Directional search algorithms based on the minimum distance between points are applied for finding the best matches to the sketch. The results are ranked according to the similarity and presented to the user. The system was developed in two stages. An initial version of the system was implemented and evaluated by conducting a user study. Modifications were made where appropriate, according to the results and the feedback, to make the system more accurate and usable. We present the details of the initial system, the user study and the results, and the modifications thus made. The overall accuracy of retrieval for the initial system was approximately 93%, when tested on a collection of data from a real-life experiment. This is improved to approximately 97% after the modifications. The user interaction strategy and the search algorithms are usable in any environment for automated retrieval of locomotion patterns. The subjects who evaluated the system found it easy to learn and use. Their comments included several prospective applications for the user interaction strategy, providing valuable insight for future directions.Gamhewage C. de Silva, Toshihiko Yamasaki, and Kiyoharu Aizawa© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2009/982867.htmlPacket-level Forward Error Control (FEC) for video streaming over a wireless network has received comparatively limited investigation, because of the delay introduced by the need to assemble a group of packets. However, packet-level interleaving when combined with FEC presents a remedy to time-correlated error bursts, though it can further increase delay if this issue is not addressed. This paper proposes adapting the overall degree of interleaved packet-level FEC according to the display deadlines of packets, transmit buffer occupation, and estimated video input to the wireless channel, all of which address the issue of delay. To guard against estimation error, the scheme applies a conservative adaptation policy, which accounts for picture type importance to ensure that display deadlines are met, thus avoiding this defect of interleaving. The paper additionally introduces a greedy algorithm that effectively groups packet-level FEC protection according to packet priority. Priority encoding adds extra protection during deep fades. As feedback is not required, the interleaving scheme is suitable for all forms of video broadcast. A Bluetooth piconet demonstrates the packet-level FEC interleaving scheme, which provides higher quality delivered video compared to the industry-standard Pro-MPEG Cop#3r2 interleaving scheme.Rouzbeh Razavi, Martin Fleury, and Mohammed Ghanbari© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2009/640386.htmlVisual sensor networks have emerged as an important class of sensor-based distributed intelligent systems, with unique performance, complexity, and quality of service challenges. Consisting of a large number of low-power camera nodes, visual sensor networks support a great number of novel vision-based applications. The camera nodes provide information from a monitored site, performing distributed and collaborative processing of their collected data. Using multiple cameras in the network provides different views of the scene, which enhances the reliability of the captured events. However, the large amount of image data produced by the cameras combined with the network's resource constraints require exploring new means for data processing, communication, and sensor management. Meeting these challenges of visual sensor networks requires interdisciplinary approaches, utilizing vision processing, communications and networking, and embedded processing. In this paper, we provide an overview of the current state-of-the-art in the field of visual sensor networks, by exploring several relevant research directions. Our goal is to provide a better understanding of current research problems in the different research fields of visual sensor networks, and to show how these different research fields should interact to solve the many challenges of visual sensor networks.Stanislava Soro and Wendi Heinzelman© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2009/905890.htmlThe increasing variety of networks and end systems, especially wireless devices, pose new challenges in communication support for, particularly, multicast-based collaborative applications. In traditional multicasting, the sender transmits video at the same rate and resolution to all receivers independent of their network characteristics, end system equipment, and users' preferences about video quality and significance. Such an approach results in resources being wasted and may also result in some receivers having their quality expectations unsatisfied. This problem can be addressed, near the network edge, by applying dynamic, in-network adaptation (e.g., transcoding) of video streams to meet available connection bandwidth, machine characteristics, and client preferences. In this paper, we extrapolate from earlier work of Shorfuzzaman et al. 2006 in which we implemented and assessed an MPEG-1 transcoding system on the Intel IXP1200 network processor to consider the feasibility of in-network transcoding for other video formats and network processor architectures. The use of “on-the-fly” video adaptation near the edge of the network offers the promise of simpler support for a wide range of end devices with different display, and so forth, characteristics that can be used in different types of environments.Mohammad Shorfuzzaman, Rasit Eskicioglu, and Peter Graham© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/983735.htmlMohammed Ghanbari, Feng Wu, Cha Zhang, Ghassan Alregib, and Athanasios Vasilakos© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/615186.htmlRemote access of scientific instruments over the Internet (i.e., remote instrumentation) demand high-resolution (2D and 3D) video image transfers with simultaneous real-time mouse and keyboard controls. Consequently, user quality of experience (QoE) is highly sensitive to network bottlenecks. Further, improper user control while reacting to impaired video caused due to network bottlenecks could result in physical damages to the expensive instrument equipment. Hence, it is vital to understand the interplay between (a) user keyboard/mouse actions toward the instrument, and (b) corresponding network reactions for transfer of instrument video images toward the user. In this paper, we first present an analytical model for characterizing user and network interplay during remote instrumentation sessions in terms of demand and supply interplay principles of traditional economics. Next, we describe the trends of the model parameters using subjective and objective measurements obtained from QoE experiments. Thereafter, we describe our Remote Instrumentation Collaboration Environment (RICE) software that leverages our experiences from the user and network interplay studies, and has functionalities that facilitate reliable and efficient remote instrumentation such as (a) network health awareness to detect network bottleneck periods, and (b) collaboration tools for multiple participants to interact during research and training sessions.Prasad Calyam, Abdul Kalash, Ramya Gopalan, Sowmya Gopalan, and Ashok Krishnamurthy© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/426981.htmlThe Virtual Immersive Learning (VIL) test bench implements a virtual collaborative immersive environment, capable of integrating natural contexts and typical gestures, which may occur during traditional lectures, enhanced with advanced experimental sessions. The system architecture is described, along with the motivations, and the most significant choices, both hardware and software, adopted for its implementation. The novelty of the approach essentially relies on its capability of embedding functionalities that stem from various research results (mainly carried out within the VICOM national project), and “putting the pieces together” in a well-integrated framework. These features, along with its high portability, good flexibility, and, above all, low cost, make this approach appropriate for educational and training purposes, mainly concerning measurements on telecommunication systems, at universities and research centers, as well as enterprises. Moreover, the methodology can be employed for remote access to and sharing of costly measurement equipment in many different activities. The immersive characteristics of the framework are illustrated, along with performance measurements related to a specific application.Luca Berruti, Franco Davoli, Sandro Zappatore, Gianluca Massei, and Amedeo Scarpiello© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/853816.htmlAugmented reality (AR) on a head-mounted display is conveniently supported by a wearable wireless network. If, in addition, the AR display is moderated to take account of the cognitive load of the wearer, then additional biosensors form part of the network. In this paper, the impact of these additional traffic sources is assessed. Rateless coding is proposed to not only protect the fragile encoded video stream from wireless noise and interference but also to reduce coding overhead. The paper proposes a block-based form of rateless channel coding in which the unit of coding is a block within a packet. The contribution of this paper is that it minimizes energy consumption by reducing the overhead from forward error correction (FEC), while error correction properties are conserved. Compared to simple packet-based rateless coding, with this form of block-based coding, data loss is reduced and energy efficiency is improved. Cross-layer organization of piggy-backed response blocks must take place in response to feedback, as detailed in the paper. Compared also to variants of its default FEC scheme, results from a Bluetooth (IEEE 802.15.1) wireless network show a consistent improvement in energy consumption, packet arrival latency, and video quality at the AR display.R. Razavi, M. Fleury, and M. Ghanbari© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/164027.htmlThe recent scalable video coding (SVC) extension to the H.264/AVC video coding standard has unprecedented compression efficiency while supporting a wide range of scalability modes, including temporal, spatial, and quality (SNR) scalability, as well as combined spatiotemporal SNR scalability. The traffic characteristics, especially the bit rate variabilities, of the individual layer streams critically affect their network transport. We study the SVC traffic statistics, including the bit rate distortion and bit rate variability distortion, with long CIF resolution video sequences and compare them with the corresponding MPEG-4 Part 2 traffic statistics. We consider (i) temporal scalability with three temporal layers, (ii) spatial scalability with a QCIF base layer and a CIF enhancement layer, as well as (iii) quality scalability modes FGS and MGS. We find that the significant improvement in RD efficiency of SVC is accompanied by substantially higher traffic variabilities as compared to the equivalent MPEG-4 Part 2 streams. We find that separately analyzing the traffic of temporal-scalability only encodings gives reasonable estimates of the traffic statistics of the temporal layers embedded in combined spatiotemporal encodings and in the base layer of combined FGS-temporal encodings. Overall, we find that SVC achieves significantly higher compression ratios than MPEG-4 Part 2, but produces unprecedented levels of traffic variability, thus presenting new challenges for the network transport of scalable video.Geert Van der Auwera, Prasanth T. David, Martin Reisslein, and Lina J. Karam© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/841590.htmlHaptic information originates from a different human sense (touch), therefore the quality of service (QoS) required to support haptic traffic is significantly different from that used to support conventional real-time traffic such as voice or video. Each type of network impairment has different (and severe) impacts on the user's haptic experience. There has been no specific provision of QoS parameters for haptic interaction. Previous research into distributed haptic virtual environments (DHVEs) have concentrated on synchronization of positions (haptic device or virtual objects), and are based on client-server architectures. We present a new peer-to-peer DHVE architecture that further extends this to enable force interactions between two users whereby force data are sent to the remote peer in addition to positional information. The work presented involves both simulation and practical experimentation where multimodal data is transmitted over a QoS-enabled IP network. Both forms of experiment produce consistent results which show that the use of specific QoS classes for haptic traffic will reduce network delay and jitter, leading to improvements in users' haptic experiences with these types of applications.Alan Marshall, Kian Meng Yap, and Wai Yu© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/569848.htmlThe increasing interest in systems able to provide users with immersive services (e.g., domotics, context-aware applications, and immersive distance learning tools) has encouraged the development of cheap and effective platforms aimed at tracking objects and people within a certain space. In this context, wireless sensor networks (WSNs) can play a very important role, since specialized sensors can be fruitfully exploited in order to generate/receive signals by means of which the WSN can derive the position of nodes joined to the objects to be tracked. The paper presents an original localization platform that exploits a single-hop WSN, based on a Microchip MCU and a Cypress RF device, to track its moving nodes. Specifically, the nodes of the network are divided into three sets: the first set consists of anchor nodes that, according to the commands from the sink (the central node of the WSN), generate ultrasonic pulses. These pulses are received by the second set of (moving) nodes, which estimate the pulse time trip and communicate it to the sink. Finally, the last set is constituted by general purpose nodes that collect any kind of data from the surrounding field. The sink gathers all the data, computes the position of moving nodes, and transfers information to external users on the Internet. The algorithms adopted to manage the network and to localize moving nodes are discussed. A working prototype based upon the hardware platform, software, and protocol described in this paper has been deployed and tested, and some results are shown. Simulation results of the localization system are presented to show system scalability.Livio Denegri, Sandro Zappatore, and Franco Davoli© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/905065.htmlThe buyer-seller watermarking protocol enables a seller to successfully identify a traitor from a pirated copy, while preventing the seller from framing an innocent buyer. Based on finite field theory and the homomorphic property of public key cryptosystems such as RSA, several buyer-seller watermarking protocols (N. Memon and P. W. Wong (2001) and C.-L. Lei et al. (2004)) have been proposed previously. However, those protocols require not only large computational power but also substantial network bandwidth. In this paper, we introduce a new buyer-seller protocol that overcomes those weaknesses by managing the watermarks. Compared with the earlier protocols, ours is n times faster in terms of computation, where n is the number of watermark elements, while incurring only O(1/lN) times communication overhead given the finite field parameter lN. In addition, the quality of the watermarked image generated with our method is better, using the same watermark strength.Yongdong Wu and Hweehua Pang© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/928521.htmlLimited bandwidth and high packet loss rate pose a serious challenge for video streaming applications over wireless networks. Even when packet loss is not present, the bandwidth fluctuation, as a result of an arbitrary number of active flows in an IEEE 802.11 network, can significantly degrade the video quality. This paper aims to enhance the quality of video streaming applications in wireless home networks via a joint optimization of video layer-allocation technique, admission control algorithm, and medium access control (MAC) protocol. Using an Aloha-like MAC protocol, we propose a novel admission control framework, which can be viewed as an optimization problem that maximizes the average quality of admitted videos, given a specified minimum video quality for each flow. We present some hardness results for the optimization problem under various conditions and propose some heuristic algorithms for finding a good solution. In particular, we show that a simple greedy layer-allocation algorithm can perform reasonably well, although it is typically not optimal. Consequently, we present a more expensive heuristic algorithm that guarantees to approximate the optimal solution within a constant factor. Simulation results demonstrate that our proposed framework can improve the video quality up to 26% as compared to those of the existing approaches.Monchai Lertsutthiwong, Thinh Nguyen, and Alan Fern© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/697454.htmlThis paper presents a hybrid (geometry- & image-based) framework suitable for providing photorealistic walkthroughs of large, complex outdoor scenes at interactive frame rates. To this end, based just on a sparse set of real stereoscopic views from the scene, a set of morphable 3D-mosaics is automatically constructed first, and then, during rendering, a continuous morphing between those 3D-mosaics that are nearby to the current viewpoint is taking place. The morphing is both photometric, as well as geometric, while we also ensure that it proceeds in a physically valid manner, thus remaining transparent to the user. The effectiveness of our framework has been demonstrated in the 3D visual reconstruction of the Samaria Gorge in Crete, which is one of the largest and most beautiful gorges in Europe.Nikos Komodakis and Georgios Tziritas© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/592690.htmlAutomating the process of semantic annotation of digital personal photographs is a crucial step towards efficient and effective management of this increasingly high volume of content. However, this is still a highly challenging task for the research community. This paper proposes a novel solution. Our solution integrates all contextual information available to and from the users, such as their daily emails, schedules, chat archives, web browsing histories, documents, online news, Wikipedia data, and so forth. We then analyze this information and extract important semantic terms, using them as semantic keyword suggestions for their photos. Those keywords are in the form of named entities, such as names of people, organizations, locations, and date/time as well as high frequency terms. Experiments conducted with 10 subjects and a total of 313 photos proved that our proposed approach can significantly help users with the annotation process. We achieved a 33% gain in annotation time as compared to manual annotation. We also obtained very positive results in the accuracy rate of our suggested keywords.Supheakmungkol Sarin, Toshinori Nagahashi, Tadashi Miyosawa, and Wataru Kameyama© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/825671.htmlThere are several advantages to creating multimedia item types and applying computer-based adaptive testing in education. First is the capability to motivate learning by making the learners feel more engaged and in an interactive environment. Second is a better concept representation, which is not possible in conventional multiple-choice tests. Third is the advantage of individualized curriculum design, rather than a curriculum designed for an average student. Fourth is a good choice of the next question, associated with the appropriate difficulty level based on a student's response to the current question. However, many issues need to be addressed when achieving these goals, including: (a) the large number of item types required to represent the current multiple-choice questions in multimedia formats, (b) the criterion used to determine the difficulty level of a multimedia question item, and (c) the methodology applied to the question selection process for individual students. In this paper, we propose a multimedia item shell design that not only reduces the number of item types required, but also computes difficulty level of an item automatically. The concept of question seed is introduced to make content creation more cost-effective. The proposed item shell framework facilitates efficient communication between user responses at the client, and the scoring agents integrated with a student ability assessor at the server. We also describe approaches for automatically estimating difficulty level of questions, and discuss preliminary evaluation of multimedia item types by students.Irene Cheng and Anup Basu© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/720685.htmlJianwei Huang, Zhu Li, and Qian Zhang© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/265309.htmlWe present a stream tapping protocol that involves clients in the video distribution process. As in conventional stream tapping, our protocol allows new clients to tap the most recent broadcast of the video they are watching. While conventional stream tapping required the server to send to these clients the part of the video they missed, our protocol delegates this task to the clients that are already watching the video, thus greatly reducing the workload of the server. Unlike previous solutions involving clients in the video distribution process, our protocol works with clients that can only upload video data at a fraction of the video consumption rate and includes a mechanism to control its network bandwidth consumption.Santosh Kulkarni, Jehan-François Pâris, and Purvi Shah© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/543674.htmlAlthough cross-layer has been thought as one of the most effective and efficient ways for multimedia communications over wireless networks and a plethora of research has been done in this area, there is still lacking of a rigorous mathematical model to gain in-depth understanding of cross-layer design tradeoffs, spanning from application layer to physical layer. As a result, many existing cross-layer designs enhance the performance of certain layers at the price of either introducing side effects to the overall system performance or violating the syntax and semantics of the layered network architecture. Therefore, lacking of a rigorous theoretical study makes existing cross-layer designs rely on heuristic approaches which are unable to guarantee sound results efficiently and consistently. In this paper, we attempt to fill this gap and develop a new methodological foundation for cross-layer design in wireless multimedia communications. We first introduce a delay-distortion-driven cross-layer optimization framework which can be solved as a large-scale dynamic programming problem. Then, we present new approximate dynamic programming based on significance measure and sensitivity analysis for high-dimensional nonlinear cross-layer optimization in support of real-time multimedia applications. The major contribution of this paper is to present the first rigorous theoretical modeling for integrated cross-layer control and optimization in wireless multimedia communications, providing design insights into multimedia communications over current wireless networks and throwing light on design optimization of the next-generation wireless multimedia systems and networks.Song Ci, Haohong Wang, and Dalei Wu© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/624941.htmlAggregates of real-time traffic may experience changes in their statistical characteristics often manifesting non stationary behavior. In multi protocol label switching (MPLS) networks this type of the traffic is assigned constant amount of resources. This may result in ineffective usage of resources when the load is below than expected or inappropriate performance when the load is higher. In this paper we propose new algorithm for dynamic resource adaptation to temporarily changing traffic conditions. Assuming that network nodes may reallocate resources on-demand using automatic bandwidth adjustment capability of MPLS framework, the proposed algorithm, implemented at ingress MPLS nodes, dynamically decides which amount of resources is currently sufficient to handle arriving traffic with given performance metrics. This decision is then communicated to interior MPLS nodes along the label switched path. As a basic tool of the algorithm we use change-point statistical test that signals time instants at which statistical characteristics of traffic aggregates change. The major advantage of the proposed approach is that it is fully autonomous, that is, network nodes do not need any support from hosts in terms of resource reservation requests. The proposed algorithm is well suited for traffic patterns experiencing high variability, especially, for non stationary type of the traffic.D. Moltchanov© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/043739.abs.htmlStavros Kotsopoulos and Tasos Dagiuklas© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/052679.abs.htmlYi Cui, Ben Y. Zhao, and S. Chen© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/012308.abs.htmlAudio delivery and reproduction for home or professional applications may greatly benefit from the adoption of digital wireless local area network (WLAN) technologies. The most challenging aspect of such integration relates the synchronized and robust real-time streaming of multiple audio channels to multipoint receivers, for example, wireless active speakers. Here, it is shown that current WLAN solutions are susceptible to transmission errors. A detailed study of the IEEE802.11e protocol (currently under ratification) is also presented and all relevant distortions are assessed via an analytical and experimental methodology. A novel synchronization scheme is also introduced, allowing optimized playback for multiple receivers. The perceptual audio performance is assessed for both stereo and 5-channel applications based on either PCM or compressed audio signals.Nicolas-Alexander Tatlas, Andreas Floros, Thomas Zarouchas, and John Mourjopoulos© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/273187.htmlA collaborative access scheme that exploits the broadcast nature of the wireless communication in order to achieve multicast content delivery is presented in this paper. The key idea is that individual clients requesting for the same content can collaborate and share the same data channel. As opposed to broadcasting, this method enables the clients to determine online the delivered content, and thus supports on-demand services. On the other hand, a multicast content delivery is much more efficient than a unicast content distribution, which must use a dedicated data channel per each and every client. This method is particularly suitable for sessions having a long-time duration, for applications in which clients can subscribe to ahead of time, and for applications in which the clients receive the same information simultaneously. A multicast content distribution increases the network service throughput in terms of the expected number of clients served simultaneously, and therefore it offers a reduced waiting time for content delivery at highly loaded time periods. It is shown that the problem of maximizing the efficiency of distributing a content in a wireless network is NP-hard. An approximation algorithm is therefore used, that for any 0<ε<1 finds an approximation solution with a relative accuracy ε. The proposed method does not require any hardware modification on the network equipment. Thus, it can be easily implemented.Zohar Naor© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/628970.htmlWe consider rate-distortion optimized strategies for dropping frames from multiple conversational and streaming videos sharing limited network node resources. The dropping strategies are based on side information that is extracted during encoding and is sent along the regular bitstream. The additional transmission overhead and the computational complexity of the proposed frame dropping schemes are analyzed. Our experimental results show that a significant improvement in end-to-end performance is achieved compared to priority-based random early dropping.Wei Tu, Jacob Chakareski, and Eckehard Steinbach© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2008/739192.htmlScalable video coding (SVC) is a new video coding format which provides scalability in three-dimensional (spatio-temporal-SNR) space. In this paper, we focus on the adaptation in SNR dimension. Usually, an SVC bitstream may contain multiple spatial layers, and each spatial layer may be enhanced by several FGS layers. To meet a bitrate constraint, the fine-grained scalability (FGS) data of different spatial layers can be truncated in various manners. However, the contributions of FGS layers to the overall/collective video quality are different. In this work, we propose an optimized framework to control the SNR scalability across multiple spatial layers. Our proposed framework has the flexibility in allocating the resource (i.e., bitrate) among spatial layers, where the overall quality is defined as a function of all spatial layers' qualities and can be modified on the fly.Truong Cong Thang, Jung Won Kang, Jeong-Ju Yoo, and Yong Man Ro© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/030893.abs.htmlMultimedia traffic makes network provisioning a key issue. Optimal provisioning of network resources is crucial for reducing the service cost of multimedia transmission. Multimedia traffic requires not only provisioning bandwidth and buffer resources in the network but also guaranteeing a given maximum end-to-end delay. In this paper we present methods and tools for the optimal dimensioning of networks based on multimedia aggregates. The proposed method minimises the network resources reservations of traffic aggregates providing a bounded delay. The paper also introduces several methods to generate multimedia traffic aggregation using real video traces. The method is evaluated using a network topology based on the European GÉANT network. The results of these simulations allow us to discover the relationship between a required delay and the necessary bandwidth reservation (or the achievable utilisation limit). An interesting conclusion of these scenarios is that, following several recommendations, the network utilisation can reach values of around 80% or higher.Enrique Hernández-Orallo and Joan Vila-Carbó© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/061391.abs.htmlZhu Han, Haohong Wang, D. Oliver Wu, Jianwei Huang, and M. Van Der Schaar© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/028340.abs.htmlA software platform is exposed, which was developed to enable demonstration and capacity testing. The platform simulates a joint optimized wireless video transmission. The development succeeded within the frame of the IST-PHOENIX project and is based on the system optimization model of the project. One of the constitutive parts of the model, the wireless network segment, is changed to a detailed, standard UTRA network simulation module. This paper consists of (1) a brief description of the projects simulation chain, (2) brief description of the UTRAN system, and (3) the integration of the two segments. The role of the UTRAN part in the joint optimization is described, with the configuration and control of this element. Finally, some simulation results are shown. In the conclusion, we show how our simulation results translate into real-world performance gains.Attila Zsiros, Attila Fülöp, and Gábor Jeney© 2010, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/am/2007/071458.abs.htmlQueue Proportional Scheduling (QPS) has been shown to be throughput optimal for Gaussian Broadcast Channels. This paper examines the use of QPS for Video Broadcasting. First, the behavior of QPS is examined as the scheduling frequency is reduced and a method is proposed that uses statistics on the arrival rates to improve its performance. The reduction of the scheduling frequency simplifies the scheduler and decreases the required operations. Then, the packet delay variation is modeled using a Markov Chain approach leading to a method for approximating the packet delay distribution. Based on the resulting distribution, it is discussed how the video encoding rate can be chosen in order to reduce the expected distortion of streams transmitted through Broadcast Channels.Dimitris Toumpakaris and Stavros Kotsopoulos© 2010, Hindawi Publishing Corporation. All rights reserved.