14119951
Drawing Planar Graphs with Circular Arcs
In this paper we address the problem of drawing planar graphs with circular arcs while maintaining good angular resolution and small drawing area. We present a lower bound on the area of drawings in which edges are drawn using exactly one circular arc. We also give an algorithm for drawing n-vertex planar graphs such that the edges are sequences of two continuous circular arcs. The algorithm runs in O(n) time and embeds the graph on the O(n) × O(n) grid, while maintaining θ(1/d(v)) angular resolution, where d(v) is the degree of vertex v. Since in this case we use circular arcs of infinite radius, this is also the first algorithm to simultaneously achieve good angular resolution, small area and at most one bend per edge using straight-line segments. Finally, we show how to create drawings in which edges are smooth C 1-continuous curves, represented by a sequence of at most three circular arcs.
1870789
Replication and retrieval strategies of multidimensional data on parallel disks
Aside from enhancing data availability during disk failures, replication of data is also used to speed up I/O performance of read-intensive applications. There are two issues that need to be addressed: (a) data placement (Which disks should store the copies of each data block?) and (b) scheduling (Given a query Q, and a placement scheme P of the data, from which disk should each block in Q be retrieved so that retrieval time is minimized?) In this paper, we consider range queries and assume that the dataset is a multidimensional grid and r copies of each unit block of the grid must be stored among M disks. To accurately measure performance of a scheduling algorithm, we consider a metric that takes into account the scheduling overhead as well as the time it takes to retrieve the data blocks from the disks. We describe several combinations of data placement schemes and scheduling algorithms and analyze their performance for range queries with respect to the above metric. We then present simulation results for the most interesting case r=2, showing that the strategies do perform better than the previously known method, especially for large queries.
5951564
Balanced matching of buyers and sellers in e-marketplaces: the barter trade exchange model
In this paper, we describe the operation of barter trade exchanges by identifying key techniques used by trade brokers to stimulate trade and satisfy member needs, and present algorithms to automate some of these techniques. In particular, we develop algorithms that emulate the practice of trade brokers by matching buyers and sellers in such a way that trade volume is maximized while the balance of trade is maintained as much as possible. We show that the buyer/seller matching and trade balance problems can be decoupled, permitting efficient solution as well as numerous options for matching strategies.We model the trade balance problem as a minimum cost circulation problem (MCC) on a network. When the products have uniform cost or when the products can be traded in fractional units, we solve the problem exactly. Otherwise, we present a novel stochastic rounding algorithm that takes the fractional optimal solution to the trade balance problem and produces a valid integer solution. We then make use of a greedy heuristic that attempts to match buyers and sellers so that the average number of suppliers that a buyer must use to satisfy a given product need is minimized.We present results on the empirical evaluation of our algorithms on test problems and simulations. Experiments show that our algorithm (MCC + stochastic rounding) runs in a fraction of the time of a commercial mixed integer programming (MIP) package while producing solutions that are always within 0.7% of the MIP solution. We evaluate the effectiveness of our algorithm on maintaining balance and on stimulating trade using two different simulation techniques, both based on transaction history data from a trade exchange. The simulation results support the barter trade exchange rule of thumb that maximizing single-period trade volume while maintaining balance of trade helps to maximize trade volume over the long run.
34686455
Drawing planar graphs with circular arcs
In this paper we address the problem of drawing planar graphs with circular arcs while maintaining good angular resolution and small drawing area. We present a lower bound on the area of drawings in which edges are drawn using exactly one circular arc. We also give an algorithm for drawing n-vertex planar graphs such that the edges are sequences of two continuous circular arcs. The algorithm runs in O(n) time and embeds the graph on the O(n) × O(n) grid, while maintaining Θ(1/d(v)) angular resolution, where d(v) is the degree of vertex v. Since in this case we use circular arcs of infinite radius, this is also the first algorithm that simultaneously achieves good angular resolution, small area, and at most one bend per edge using straight-line segments. Finally, we show how to create drawings in which edges are smooth C1-continuous curves, represented by a sequence of at most three circular arcs.
15084300
Joint Optimization of Word Alignment and Epenthesis Generation for Chinese to Taiwanese Sign Synthesis
This work proposes a novel approach to translate Chinese to Taiwanese sign language and to synthesize sign videos. An aligned bilingual corpus of Chinese and Taiwanese sign language (TSL) with linguistic and signing information is also presented for sign language translation. A two-pass alignment in syntax level and phrase level is developed to obtain the optimal alignment between Chinese sentences and Taiwanese sign sequences. For sign video synthesis, a scoring function is presented to develop motion transition-balanced sign videos with rich combinations of intersign transitions. Finally, the maximum a posteriori (MAP) algorithm is employed for sign video synthesis based on joint optimization of two-pass word alignment and intersign epenthesis generation. Several experiments are conducted in an educational environment to evaluate the performance on the comprehension of sign expression. The proposed approach outperforms the IBM Model2 in sign language translation. Moreover, deaf students perceived sign videos generated by the proposed method to be satisfactory
29287906
Further complexity reduction of parallel FIR filters
Based on recently published low complexity parallel FIR filter structures, this paper proposes a new scheme to further reduce their hardware complexity. A FIR filter is firstly transformed into linear convolution, which is then implemented by the iterated short convolution algorithm. This linear convolution structure for FIR filter is used as a processing core to implement the subfilters of previously proposed parallel FIR filter structures. A large amount of hardware can be saved by the new scheme. For example, for a 576-tap FIR filter, when the parallelism level changes from 12 to 72, the new scheme can save 1755 to 3375 multiplications at the cost of 21 to 4658 additions and 1516 to 4749 delay elements, respectively.