676 research outputs found
Generalized Lineage-Aware Temporal Windows: Supporting Outer and Anti Joins in Temporal-Probabilistic Databases
The result of a temporal-probabilistic (TP) join with negation includes, at
each time point, the probability with which a tuple of a positive relation
matches none of the tuples in a negative relation , for a
given join condition . TP outer and anti joins thus resemble the
characteristics of relational outer and anti joins also in the case when there
exist time points at which input tuples from have non-zero
probabilities to be and input tuples from have non-zero
probabilities to be , respectively. For the computation of TP joins with
negation, we introduce generalized lineage-aware temporal windows, a mechanism
that binds an output interval to the lineages of all the matching valid tuples
of each input relation. We group the windows of two TP relations into three
disjoint sets based on the way attributes, lineage expressions and intervals
are produced. We compute all windows in an incremental manner, and we show that
pipelined computations allow for the direct integration of our approach into
PostgreSQL. We thereby alleviate the prevalent redundancies in the interval
computations of existing approaches, which is proven by an extensive
experimental evaluation with real-world datasets
Dividend reductions and signaling in an imputation environment
In contrast to the double taxation system prevailing in the U.S., Australian firms operate within an imputation tax environment with respect to dividend payments. We argue that the dividend imputation tax system increases the signaling potential of dividend reductions and our empirical findings strongly support this view. We find that the size of the dividend reduction is related to the tax credit status of the dividend. Abnormal changes in profitability are negative in the year following dividend reductions and are negatively related to the dividend reduction; similar signaling effects are found in terms of price reactions. The significance levels for the relations between abnormal change in profitability and dividend reductions, and price reactions and dividend reductions are statistically significantly stronger for dividends with associated tax credits. Overall, our study conclusively demonstrates that dividend reductions in Australia have strong signaling power and, as such, our results are at variance with the results obtained in the U.S
Fast Heuristic and Exact Algorithms for Two-Level Hazard-Free Logic Minimization
None of the available minimizers for 2-level hazard-free logic minimization can synthesize very large circuits. This limitation has forced researchers to resort to manual and automated circuit partitioning techniques. This paper introduces two new 2-level logic minimizers:ESPRESSO-HF, a heuristic method which is loosely based on ESPRESSO-II, and IMPYMIN, an exact method based on implicit data structures. Both minimizers can solve all currently available examples, which range up to 32 inputs and 33 outputs.These include examples that have never been solved before.For examples that can be solved by other minimizers our methods are several orders of magnitude faster. As by-products of these algorithms, we also present two additional results. First, we introduce a fast new algorithm to check if a hazard-free covering problem can feasibly be solved. Second, we introduce a novel formulation of the 2-level hazard-free logic minimization problem by capturing hazard-freedom constraints within a synchronous function by adding new variables
Fast Heuristic and Exact Algorithms for Two-Level Hazard-Free Logic Minimization
None of the available minimizers for 2-level hazard-free logic minimization can synthesize very large circuits. This limitation has forced researchers to resort to manual and automated circuit partitioning techniques. This paper introduces two new 2-level logic minimizers:ESPRESSO-HF, a heuristic method which is loosely based on ESPRESSO-II, and IMPYMIN, an exact method based on implicit data structures. Both minimizers can solve all currently available examples, which range up to 32 inputs and 33 outputs.These include examples that have never been solved before.For examples that can be solved by other minimizers our methods are several orders of magnitude faster. As by-products of these algorithms, we also present two additional results. First, we introduce a fast new algorithm to check if a hazard-free covering problem can feasibly be solved. Second, we introduce a novel formulation of the 2-level hazard-free logic minimization problem by capturing hazard-freedom constraints within a synchronous function by adding new variables
Federal Trade Commission v. Wyndham Hotels
Letter requesting oral argumen
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