9323396
Inducing Word Alignments with Bilexical Synchronous Trees
This paper compares different bilexical tree-based models for bilingual alignment. EM training for the new model benefits from the dynamic programming "hook trick". The model produces improved dependency structure for both languages.
2506060
Synchronous Binarization for Machine Translation
Systems based on synchronous grammars and tree transducers promise to improve the quality of statistical machine translation output, but are often very computationally intensive. The complexity is exponential in the size of individual grammar rules due to arbitrary re-orderings between the two languages, and rules extracted from parallel corpora can be quite large. We devise a linear-time algorithm for factoring syntactic re-orderings by binarizing synchronous rules when possible and show that the resulting rule set significantly improves the speed and accuracy of a state-of-the-art syntax-based machine translation system.
10184956
Mesh Simplification Based on Shading Characteristic
Mesh simplification is a key research area in scientific visualization and virtual reality. The paper presents a new method of polyhedral model simplification based on vision characteristic and edge collapse. This method determines model ’s vision characteristic by computing the maximum product of angle between normal of vertex and adjacent triangles with area of these triangles. It can achieve a high decimation rate, while keeping the details of vision. This algorithm can also be extended to triangle decimation criterion easily.
6715931
Evaluating guidelines for empirical software engineering studies
Background. Several researchers have criticized the standards of performing and reporting empirical studies in software engineering. In order to address this problem, Andreas Jedlitschka and Dietmar Pfahl have produced reporting guidelines for controlled experiments in software engineering. They pointed out that their guidelines needed evaluation. We agree that guidelines need to be evaluated before they can be widely adopted. If guidelines are flawed, they will cause more problems that they solve.Aim. The aim of this paper is to present the method we used to evaluate the guidelines and report the results of our evaluation exercise. We suggest our evaluation process may be of more general use if reporting guidelines for other types of empirical study are developed.Method. We used perspective-based inspections to perform a theoretical evaluation of the guidelines. A separate inspection was performed for each perspective. The perspectives used were: Researcher, Practitioner/Consultant, Meta-analyst, Replicator, Reviewer and Author. Apart from the Author perspective, the inspections were based on a set of questions derived by brainstorming. The inspection using the Author perspective reviewed each section of the guidelines sequentially. Results. The question-based perspective inspections detected 42 issues where the guidelines would benefit from amendment or clarification and 8 defects.Conclusions. Reporting guidelines need to specify what information goes into what section and avoid excessive duplication. Software engineering researchers need to be cautious about adopting reporting guidelines that differ from those used by other disciplines. The current guidelines need to be revised and the revised guidelines need to be subjected to further theoretical and empirical validation. Perspective-based inspection is a useful validation method but the practitioner/consultant perspective presents difficulties.
7846317
Throughput differentiation using coloring at the network edge and preferential marking at the core
In this paper we introduce an innovation in differentiated services architecture consisting of adaptive two-level coloring at the edge and preferential marking at the core. We identify general properties of these two processes which, when met, guarantee a desirable fixed point for the network; i.e., one where aggregated flow rates meet or exceed given targets in an over-provisioned network. Specific mechanisms realizing the aforementioned properties lead to so-called active rate management controllers for edge coloring, and a preferentially-marking, active queue management controller at the core. We discuss stability of the fixed point for this network, and validate results using ns simulations.
14879615
Qualitative simulation model for software engineering process
Software process simulation models hold out the promise of improving project planning and control. However, quantitative models require a very detailed understanding of the software process. In particular, process knowledge needs to be represented quantitatively which requires extensive, reliable software project data. When such data is lacking, quantitative models must impose severe constraints, restricting the value of the models. In contrast qualitative models are able to cope with imprecise knowledge by reasoning at a more abstract level. This paper illustrates the value and flexibility of qualitative models by developing a model of the software staffing process and comparing it with other quantitative staffing models. We show that the qualitative model provides more insights into the staffing process than the quantitative models because it requires fewer constraints and can thus simulate more behaviors. In particular, the qualitative model produces three possible outcomes: adding staff can increases project duration (i.e. Brooks' Law), adding staff may not affect duration, or adding staff may decrease duration. The qualitative model allows us to determine the conditions under which the different outcomes can occur
34749580
Plane elementary bipartite graphs
A connected graph is called elementary if the union of all perfect matchings forms a connected subgraph. In this paper we mainly study various properties of plane elementary bipartite graphs so that many important results previously obtained for hexagonal systems are treated in a unified way. Firstly, we show that a plane bipartite graph G is elementary if and only if the boundary of each face (including the infinite face) is an alternating cycle with respect to some perfect matching of G. For a plane bipartite graph G all interior vertices of which are of the same degree, a stronger result is obtained; namely, G is elementary if and only if the boundary of the infinite face of G is an alternating cycle with respect to some perfect matching of G. Second, the concept of the Z-transformation graph Z(G) of a hexagonal system G (whose vertices represent the perfect matchings of G) is extended to a plane bipartite graph G and some results analogous to those for hexagonal systems are obtained. A peripheral face f of G is called reducible if the removal of the internal vertices and edges of the path that is the intersection of f and the exterior face of G results in a plane elementary bipartite graph. Thirdly, we obtain the reducible face decomposition for plane elementary bipartite graphs. Furthermore, sharp upper and lower bounds for the number of reducible faces are derived. Conversely, we can construct any plane elementary bipartite graphs by adding new peripheral faces one by one. As applications of this approach, we give simple construction methods for several types of plane elementary bipartite graphs G that contain a forcing edge (which belongs to exactly one perfect matching of G) and whose Z-transformation graphs Z(G) contain vertices of degree one.