11461597
A unification of network coding and tree-packing (routing) theorems
Given a network of lossless links with rate constraints, a source node, and a set of destination nodes, the multicast capacity is the maximum rate at which the source can transfer common information to the destinations. The multicast capacity cannot exceed the capacity of any cut separating the source from a destination; the minimum of the cut capacities is called the cut bound. A fundamental theorem in graph theory by Edmonds established that if all nodes other than the source are destinations, the cut bound can be achieved by routing. In general, however, the cut bound cannot be achieved by routing. Ahlswede et al. established that the cut bound can be achieved by performing network coding, which generalizes routing by allowing information to be mixed. This paper presents a unifying theorem that includes Edmonds' theorem and Ahlswede et al.'s theorem as special cases. Specifically, it shows that the multicast capacity can still be achieved even if information mixing is only allowed on edges entering relay nodes. This unifying theorem is established via a graph theoretic hardwiring theorem, together with the network coding theorems for multicasting. The proof of the hardwiring theorem implies a new proof of Edmonds' theorem.
487639
Intelligent Multi-hop Video Communications
In this paper, we study an intelligent multi-hop communications architecture for quality video delivery over networks. The key to this architecture is the insertion of relays with different levels of intelligence along the end-to-end path that coordinate with each other and the end-systems. We study traffic management and content adaptation within this architecture. Compared with the end-to-end model, the multi-hop model can achieve higher throughput without increasing the risk of overloading the network and the end-to-end delay. Experimental results show a throughput gain of 19.3% on a concatenation of two best-effort networks, and 37.8% for a concatenation of a best-effort network and a guaranteed service network. With the error withdrawal feature at the relay, abrupt quality drops are avoided. Analysis and simulations suggest that the multi-hop traffic management can gain high throughput, and the content adaptation should be sender-centric with occasional relay supports.
12694498
An Improvement to Unscented Transformation
This paper proposes a new sigma point selection strategy to better capture the information of a probability distribution By doing so, the non-local sampling problem inherent in the original unscented transformation (UT) is fundamentally eliminated It is argued that the improved UT (IUT) outperforms the original UT at the cost of increased but comparable computation burden and will be useful in constructing a nonlinear filter.
13420664
Music Classification Using Significant Repeating Patterns
With the popularity of multimedia applications, a large amount of music data has been accumulated on the Internet. Automatic classification of music data becomes a critical technique for providing an efficient and effective retrieval of music data. In this paper, we propose a new approach for classifying music data based on their contents. In this approach, we focus on monophonic music features represented as rhythmic and melodic sequences. Moreover, we use repeating patterns of music data to do music classification. For each pattern discovered from a group of music data, we employ a series of measurements to estimate its usefulness for classifying this group of music data. According to the patterns contained in a music piece, we determine which class it should be assigned to. We perform a series of experiments and the results show that our approach performs on average better than the approach based on the probability distribution of contextual information in music.
14594559
Detecting Critical Configuration of Six Points
When space points and camera optical center lie on a twisted cubic, no matter how many corresponding pairs there are from space points to their image points, camera projection matrix cannot be uniquely determined, in other words, the configuration of camera and space points in this case is critical for camera parameter estimation. In practice, it is important to detect this critical configuration before the estimated camera parameters are used. In this work, a new method is introduced to detect this critical configuration, which is based on an effective criterion function constructed from an invariant relationship between six space points and their corresponding image points. The advantage of this method is that no explicit computation on camera projection matrix or optical center is needed. Simulations show it is quite robust and stable against noise. Experiments on real data show the criterion function can be faithfully trusted for camera parameter estimation.
43222800
A New Recombination Lower Bound and the Minimum Perfect Phylogenetic Forest Problem
Understanding recombination is a central problem in population genetics. In this paper, we address an established problem in Computational Biology: compute lower bounds on the minimum number of historical recombinations for generating a set of sequences [11,13,9,1,2,15]. In particular, we propose a new recombination lower bound: the forest bound. We show that the forest bound can be formulated as the minimumperfect phylogenetic forest problem, a natural extension to the classic binary perfect phylogeny problem, which may be of interests on its own. We then show that the forest bound is provably higher than the optimal haplotype bound [13], a very good lower bound in practice [15].We prove that, like several other lower bounds [2], computing the forest bound isNPhard. Finally, we describe an integer linear programming (ILP) formulation that computes the forest bound precisely for certain range of data. Simulation results show that the forest bound may be useful in computing lower bounds for low quality data.
62726183
Further improve circuit partitioning using GBAW logic perturbation techniques
Efficient circuit partitioning is gaining more importance with the increasing size of modern circuits. Conventionally, circuit partitioning is solved by modeling a circuit as a hypergraph for the ease of applying graph algorithms. However there exists room for further improvement on even optimum hypergraph partitioning results, if logic information can be applied for perturbation. In this paper we present a multi-way partitioning framework which can couple any excellent hypergraph partitioner and a noval logic perturbation based technique (GBAW) for further improvement over very excellent partitioning results. Our approach can integrate with any graph partitioner. We performed experiments on 2-, 3-, 4-, and 5-way partitionings for various circuits of different sizes from MCNC benchmarks. We have chosen the state-of-the-art hMetis-Kway to obtain high quality initial solutions for the experiments. Our experiments showed that this partitioning approach can achieve a further 15% reduction in cut size for 2-way partitioning with an area penalty of only 0.33%. The good results demonstrated the effectiveness of this new partitioning technique.