This paper analyzes a novel method for constructing preconditioners for diagonally-dominant symmetric positivedefinite matrices. The method discussed here is based on a simple idea: we construct M by simply dropping offdiagonal nonzeros from A and modifying the diagonal elements to maintain a certain row-sum property. The preconditioners are extensions of Vaidya’s augmented maximum-spanning-tre...

In the recent work [7], a combinatorial problem concerning linear codes over a finite field Fq was introduced. In that work the authors studied the weight set of an [n, k]q linear code, that is the set of non-zero distinct Hamming weights, showing that its cardinality is upper bounded by q −1 q−1 . They showed that this bound was sharp in the case q = 2, and in the case k = 2. They conjectured ...

We consider a special subgraph of a weighted directed graph: one comprising only the k heaviest edges incoming to each vertex. We show that the maximum weight branching in this subgraph closely approximates the maximum weight branching in the original graph. Specifically, it is within a factor of k k+1 . Our interest in finding branchings in this subgraph is motivated by a data compression appl...

This study was conducted to examine weight change of exclusively breast-fed infants during the first week and through the first 24 days of life, and to evaluate the effect of breast-feeding factors and maternal characteristics on early weight change in the infants. The weights of 21 infants were recorded on day 1 (day of birth), and on days 3, 7, 10, 17, and 24, and the data analysed to evaluat...

This paper examines the implications of the separation of ownership and management based on a strategic export promotion policy when the shares of exporting firms are internationally owned by the residents of both countries in an international duopolistic market. Although the presence of either cross ownership or managerial delegation weakens the exporting countries’ subsidization incentives, t...

This study examines the export performance consequences of a market orientation and the potential moderating impact of the competitive, technological, and market environment. Market orientation was positively related to three dimensions of export performance: change in export sales, export profits, and change in export profits. The impact of market orientation on export profits and change in ex...