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A scalable and adaptive multicast forwarding mechanism based on ExplicitMulticast (Xcast) is described which balances the allocation of forwarding states in routers and also enhances the scalability of conventional IP multicast and Source-Specific Multicast. The empirical results demonstrate that the suggested algorithm can optimize forwarding states stored among routers.

Multiple-destination overlay multicast (MOM) is a novel multicast delivery mechanism for bandwidth-demanding applications in Internet protocol (IP) networks. Results suggest that MOM consumes less network bandwidth and less interface bandwidth.

We propose a new code family, called extended shifted prime codes, and the universal encoding architecture for spectral amplitude coding optical code division multiple access systems using a two-code keying scheme. The proposed system can eliminate multiuser interference and suppress phase-induced intensity noise. In addition, we design the ESP codes to be an encoding/decoding architecture based on the array waveguide grating architecture and reduce the power loss and the complexity of the optical line terminal. The numerical results demonstrate that the proposed system with ESP codes outperforms the existing one-dimensional shifted prime codes system. [ABSTRACT FROM AUTHOR]

With the ubiquity of cellular phones, mobile applications with 2D barcodes have drawn a lot of attentions in recent years. When a user takes a barcode image with the camera in a mobile device, the captured image tends to be blurred due to camera shaking when the user presses the shutter. In addition, the captured image includes part of the complex background of the page with the barcode. In this paper, we point out that the above two issues, which have not been identified in previous works, deteriorate the accuracy of barcode recognition in the mobile computing. We then propose an efficient and effective algorithm to restore and extract 2D barcode from a complex background in a camera-shaken image. Compared with previous approaches, our algorithm outperforms in not only smaller running time but also higher accuracy of the barcode recognition in the mobile computing. [ABSTRACT FROM AUTHOR]

In this paper, we first study an important but unsolved dilemma in the literature of subspace clustering, which is referred to as "information overlapping-data coverage" challenge. Current solutions of subspace clustering usually invoke a grid-based Apriori-like procedure to identify dense regions and construct subspace clusters afterward. Due to the nature of monotonicity property in Apriori- like procedures, it is inherent that if a region is identified as dense, all its projected regions are also identified as dense, causing overlapping/redundant clustering information to be inevitably reported to users when generating clusters from such highly correlated regions. However, naive methods to filter redundant clusters will incur a challenging problem in the other side of the dilemma, called the "data coverage" issue. Note that two clusters may have highly correlated dense regions but their data members could be highly different to each other. Arbitrarily removing one of them may lose the coverage of data with clustering information, thus likely reporting an incomplete and biased clustering result. In this paper, therefore, we further propose an innovative algorithm, called "NOnRedundant Subspace Cluster mining" (NORSC), to efficiently discover a succinct collection of subspace clusters while also maintaining the required degree of data coverage. NORSC not only avoids generating the redundant clusters with most of the contained data covered by higher dimensional clusters to resolve the information overlapping problem but also limits the information loss to cope with the data coverage problem. As shown by our experimental results, NORSC is very effective in identifying a concise and small set of subspace clusters, while incurring time complexity in orders of magnitude better than that of previous works. [ABSTRACT FROM AUTHOR]

In this paper, we leverage network coding (NC) to reduce the bandwidth consumption for data broadcast (DB). We use the concept of mixing in a different way from the traditional NC. Traditional NC mixes all data items together. However, we mix each data item from only some data items according to the queried and stored data of receivers. Therefore, each receiver in our approach is required to receive fewer coded data to decode the required information, and the sender, thereby, is able to broadcast fewer data items. We formulate an optimization problem with integer-linear programming to minimize the bandwidth consumption in DB. We prove that the problem is NP-hard and design an approximation algorithm that can be implemented in the data server. In addition, we show that different mixings of data items lead to different decoding costs for receivers. We design an algorithm to optimally code the data items with the minimum decoding cost. [ABSTRACT FROM AUTHOR]

In this paper, we propose a bandwidth-efficient multicast routing mechanism using rectilinear Steiner trees for Internet Protocol (IP)-based low earth orbit (LEO) satellite networks. Different from existing work that minimizes the end-to-end delay, our mechanism minimizes the total bandwidth, i.e., the number of hops, for a multicast tree since the wireless bandwidth in satellite networks is a limited and scarce resource. We formulate the problem as an optimization problem and propose a distributed algorithm and a protocol to support the dynamic group membership for multicasting over LEO satellite networks. Our simulation results show that the trees created by our mechanism consume less bandwidth than the shortest path trees. The difference between the optimal solutions and the solutions obtained by our distributed algorithm is within 5%. Furthermore, our protocol has a limited overhead and can support a large number of group members. [ABSTRACT FROM AUTHOR]

In this paper, we propose a bandwidth-efficient multicast mechanism for heterogeneous wireless networks. We reduce the bandwidth cost of an Internet Protocol (IP) multicast tree by adaptively selecting the cell and the wireless technology for each mobile host to join the multicast group. Our mechanism enables more mobile hosts to cluster together and leads to the use of fewer cells to save the scarce wireless bandwidth. Besides, the paths in the multicast tree connecting to the selected cells share more common links to save the wireline bandwidth. Our mechanism supports the dynamic group membership and offers mobility of group members. Moreover, our mechanism requires no modification to the current IP multicast routing protocols. We formulate the selection of the cell and the wireless technology for each mobile host in the heterogeneous wireless networks as an optimization problem. We use Integer Linear Programming to model the problem and show that the problem is NP-hard. To solve the problem, we propose a distributed algorithm based on Lagrangean relaxation and a network protocol based on the algorithm. The simulation results show that our mechanism can effectively save the wireless and wireline bandwidth as compared to the traditional IP multicast. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new mechanism to select the cells and the wireless technologies for layer-encoded video multicasting in the heterogeneous wireless networks. Different from the previous mechanisms, each mobile host in our mechanism can select a different cell with a different wireless technology to subscribe each layer of a video stream, and each cell can deliver only a subset of layers of the video stream to reduce the bandwidth consumption. We formulate the Cell and Technology Selection Problem (CTSP) to multicast each layer of a video stream as an optimization problem. We use Integer Linear Programming to model the problem and show that the problem is NP-hard, To solve the problem, we propose a distributed algorithm based on Lagrangean relaxation and a protocol based on the proposed algorithm. Our mechanism requires no change of the current video multicasting mechanisms and the current wireless network infrastructures. Our algorithm is adaptive not only to the change of the subscribers at each layer, but also the change of the locations of each mobile host. [ABSTRACT FROM AUTHOR]

IP multicasting is an efficient group communication mechanism. It avoids transmitting packets from a sender to each of the receivers separately. Under the current IP multicast model, once having joined a group, the host will receive all data destined to the group from any source, irrespective of whether it wishes to receive them. This paper studies source filtering (SF) in IP multi-casting. Source filtering allows individual hosts to specify the reception of packets sent to a multicast group only from a list of source addresses or to explicitly identify a list of the sources whose data the hosts do not want to receive. We investigate the issue of source filtering in the context of multicast routing protocols, and provide support of source filtering for shared-tree based IP multicast routing. We also discuss how source filtering improves the performance of existing work on IP multicast. Finally, we provide analysis and conduct simulations to evaluate the performance of the proposed SF mechanism. The results show that our mechanism allows better bandwidth utilization and scalability than those without the capability of source filtering, thus achieving a truly efficient use of resources for IP multicasting. [ABSTRACT FROM AUTHOR]

This paper studies the integration of multimedia multicasting, with the consideration of multicast with end-to-end QoS guarantees by resource reservation, dynamic join and departure of participants, user heterogeneity, scalability, robustness, and loop-free control. A protocol called MQ, Multicast with QoS, is proposed to support multimedia group communications with QoS guarantees for heterogeneous recipients. With MQ, while resource reservation is de-coupled from QoS multicast routing, they are integrated in a way to avoid the problem of “sender-oriented” path determination, a problem that occurs when RSVP is used in conjunction with QoS routing for heterogeneous reservations. Being a truly receiver-oriented and integrated scheme for multimedia multicasting, MQ supports such integration in a robust, scalable and loop-free way. It also accommodates heterogeneous users with varied QoS, dynamically adjusts QoS trees to improve resource utilization, and guarantees end-to-end QoS requirements. We have conducted simulations to evaluate the performance of the proposed mechanism. MQ demonstrates its advantages over the conventional loosely coupled integration of TP multicasting, resource reservation and QoS routing, in terms of better accommodation of heterogeneous users, higher scalability, lower blocking probability for users to join groups with service guarantees, and more efficient resource utilization to enhance system performance [ABSTRACT FROM PUBLISHER]