It is well-known that there are circumstances where applying Reiter's closed world assump- tion (CWA) will lead to logical inconsistencies . In this paper, a new characterization of the CWA consistency is pesented...It is well-known that there are circumstances where applying Reiter's closed world assump- tion (CWA) will lead to logical inconsistencies . In this paper, a new characterization of the CWA consistency is pesented and an algorithm is proposed for determining whether a datalase with- out function symbols is consistent with the CWA. The algorithm is shown to be efficient.展开更多
Given a hypergraph, this paper provides three algorithms for finding all its minimal cutsets, minimal link cutsets and the least cutsets. The result not only set up a new studying field on cutsets of hypergraph, but a...Given a hypergraph, this paper provides three algorithms for finding all its minimal cutsets, minimal link cutsets and the least cutsets. The result not only set up a new studying field on cutsets of hypergraph, but also lay a foundation of analyzing the performance of multibus systems. The algorithm for determining all the least cutsets in a hypergraph is polynomial complex and more efficient than that in [2].展开更多
X-ray pulsars offer stable, periodic X-ray pulse sequences that can be used in spacecraft positioning systems. A method using X-ray pulsars to determine the initial orbit of a satellite is presented in this paper. Thi...X-ray pulsars offer stable, periodic X-ray pulse sequences that can be used in spacecraft positioning systems. A method using X-ray pulsars to determine the initial orbit of a satellite is presented in this paper. This method suggests only one detector to be equipped on the satellite and assumes that the detector observes three pulsars in turn. To improve the performance, the use of incremental phase in one observation duration is proposed, and the incremental phase is combined with the time difference of arrival(TDOA). Then, a weighted least squares(WLS) algorithm is formulated to calculate the initial orbit. Numerical simulations are performed to assess the proposed orbit determination method.展开更多
文摘It is well-known that there are circumstances where applying Reiter's closed world assump- tion (CWA) will lead to logical inconsistencies . In this paper, a new characterization of the CWA consistency is pesented and an algorithm is proposed for determining whether a datalase with- out function symbols is consistent with the CWA. The algorithm is shown to be efficient.
文摘Given a hypergraph, this paper provides three algorithms for finding all its minimal cutsets, minimal link cutsets and the least cutsets. The result not only set up a new studying field on cutsets of hypergraph, but also lay a foundation of analyzing the performance of multibus systems. The algorithm for determining all the least cutsets in a hypergraph is polynomial complex and more efficient than that in [2].
基金supported by the National Natural Science Foundation of China(No.61401340)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2016JM6035)+1 种基金the Fundamental Research Funds for the Central Universities,China(No.JB161303)and the Areospace T.T.&C.Innovation Program(No.201515A)
文摘X-ray pulsars offer stable, periodic X-ray pulse sequences that can be used in spacecraft positioning systems. A method using X-ray pulsars to determine the initial orbit of a satellite is presented in this paper. This method suggests only one detector to be equipped on the satellite and assumes that the detector observes three pulsars in turn. To improve the performance, the use of incremental phase in one observation duration is proposed, and the incremental phase is combined with the time difference of arrival(TDOA). Then, a weighted least squares(WLS) algorithm is formulated to calculate the initial orbit. Numerical simulations are performed to assess the proposed orbit determination method.
