Maximum regulated takeoff weights and hence payloads of large commercial jets are limited by government regulations which take into account local airport conditions as well as a variety of safety factors. One of the c...Maximum regulated takeoff weights and hence payloads of large commercial jets are limited by government regulations which take into account local airport conditions as well as a variety of safety factors. One of the challenging conditions that must be met is linked to a minimum obstacle clearance in the unlikely event of an engine failure on the runway at the worst possible time. This requirement becomes an overriding factor for airports surrounded by challenging terrain, and therefore a well defined takeoff path out of these airports has the potential to transform a financially unsustainable operation into a commercially viable one. The research described in this paper represents an ongoing attempt to resolve this important problem and makes use of recent advances in robot path planning techniques.展开更多
For a computer to perform intelligent information processing requires functions that can extract concepts from words, as humans do, and then associate those concepts with related concepts. In order to implement this a...For a computer to perform intelligent information processing requires functions that can extract concepts from words, as humans do, and then associate those concepts with related concepts. In order to implement this association function, it is necessary to quantify the degree of association between two concepts. In the present paper, we propose a method for quantifying degree of association focusing on the viewpoint that uses a concept base （a knowledge base that expresses concepts as a collection of pairs, each pair consisting of an attribute word used to describe the concept and a weighting that expresses the word＇s importance）. Here, ＂Viewpoint＂ is the perspective from which a concept is viewed; for example, consider the degree of association between ＂airplane＂ and ＂automobile＂, and the degree of association between ＂airplane＂ and ＂bird＂. From the viewpoint of ＂vehicle＂, ＂airplane＂ and ＂automobile＂ are highly related, while from the viewpoint of ＂flight＂, ＂airplane＂ and ＂bird＂ are highly related. We present herein a comparison of two methods for calculating degree of association focusing on the viewpoint, and demonstrate that the method involving modulation of attribute weightings based on viewpoint results in degree of association calculations that are closer to human senses.展开更多
We calculate the large mass dileptons production from the jet-dilepton conversion in spherical expanding quark-gluon plasma at Relativistic Heavy Ion Collider（RHIC） and Large Hadron Collider（LHC） energies.The jetd...We calculate the large mass dileptons production from the jet-dilepton conversion in spherical expanding quark-gluon plasma at Relativistic Heavy Ion Collider（RHIC） and Large Hadron Collider（LHC） energies.The jetdilepton production exceeds the thermal and Drell Yan dilepton production in the large mass region of 4.5 GeV展开更多
Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discriminat...Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discrimination ability, and wide field of view. However, using the direct projection method, the angular resolution of this camera is limited by uncertainties in the energies estimated from pulse height and time of flight measurements. In this study, we established an eight-element neutron scatter camera and conducted the experiment with a ^(252)Cf neutron source. The results show that it has an angular resolution better than 8°(1s) and a detection efficiency of approximately 2.6′10-4. Using maximum likelihood expectation maximization method, the image artifact was eliminated, and the angular resolution was improved. We proposed an average scattering angle method to estimate the scattering energy of neutrons and Compton gamma rays. As such, we can obtain a recognizable image and energy spectrum of the source with some degradation of energy and image resolutions. Finally, a newly measured light response function based on the MPD^(-4) device was used for image reconstruction. Although we did not obtain a better result than that of the standard light response function, we have observed the effects of light response function on image reconstruction.展开更多
文摘Maximum regulated takeoff weights and hence payloads of large commercial jets are limited by government regulations which take into account local airport conditions as well as a variety of safety factors. One of the challenging conditions that must be met is linked to a minimum obstacle clearance in the unlikely event of an engine failure on the runway at the worst possible time. This requirement becomes an overriding factor for airports surrounded by challenging terrain, and therefore a well defined takeoff path out of these airports has the potential to transform a financially unsustainable operation into a commercially viable one. The research described in this paper represents an ongoing attempt to resolve this important problem and makes use of recent advances in robot path planning techniques.
文摘For a computer to perform intelligent information processing requires functions that can extract concepts from words, as humans do, and then associate those concepts with related concepts. In order to implement this association function, it is necessary to quantify the degree of association between two concepts. In the present paper, we propose a method for quantifying degree of association focusing on the viewpoint that uses a concept base （a knowledge base that expresses concepts as a collection of pairs, each pair consisting of an attribute word used to describe the concept and a weighting that expresses the word＇s importance）. Here, ＂Viewpoint＂ is the perspective from which a concept is viewed; for example, consider the degree of association between ＂airplane＂ and ＂automobile＂, and the degree of association between ＂airplane＂ and ＂bird＂. From the viewpoint of ＂vehicle＂, ＂airplane＂ and ＂automobile＂ are highly related, while from the viewpoint of ＂flight＂, ＂airplane＂ and ＂bird＂ are highly related. We present herein a comparison of two methods for calculating degree of association focusing on the viewpoint, and demonstrate that the method involving modulation of attribute weightings based on viewpoint results in degree of association calculations that are closer to human senses.
基金Supported by the Natural Science Foundation of the Education Department of Yunnan Province of China under Grant No.2012Y274Science Foundation of Dianxi Science and Technology Normal University under Grant No.LCSZL2013004
文摘We calculate the large mass dileptons production from the jet-dilepton conversion in spherical expanding quark-gluon plasma at Relativistic Heavy Ion Collider（RHIC） and Large Hadron Collider（LHC） energies.The jetdilepton production exceeds the thermal and Drell Yan dilepton production in the large mass region of 4.5 GeV
基金supported by the National Natural Science Fundation of China(Grant Nos.1110510611375144&11275153)
文摘Recently, Sandia Laboratories developed a neutron scatter camera to detect special nuclear materials. This camera exhibits the following advantages: high efficiency, direction discrimination, neutron-gamma discrimination ability, and wide field of view. However, using the direct projection method, the angular resolution of this camera is limited by uncertainties in the energies estimated from pulse height and time of flight measurements. In this study, we established an eight-element neutron scatter camera and conducted the experiment with a ^(252)Cf neutron source. The results show that it has an angular resolution better than 8°(1s) and a detection efficiency of approximately 2.6′10-4. Using maximum likelihood expectation maximization method, the image artifact was eliminated, and the angular resolution was improved. We proposed an average scattering angle method to estimate the scattering energy of neutrons and Compton gamma rays. As such, we can obtain a recognizable image and energy spectrum of the source with some degradation of energy and image resolutions. Finally, a newly measured light response function based on the MPD^(-4) device was used for image reconstruction. Although we did not obtain a better result than that of the standard light response function, we have observed the effects of light response function on image reconstruction.
