An extension of 2-D assignment approach is proposed for measurement-to-target association for improving multiple targets vector miss distance measurement accuracy. When the multiple targets move so closely, the measur...An extension of 2-D assignment approach is proposed for measurement-to-target association for improving multiple targets vector miss distance measurement accuracy. When the multiple targets move so closely, the measurements can not be fully resolved due to finite resolution. The proposed method adopts an auction algorithm to compute the feasible measurement-to-target assignment with unresolved measurements for solving this 2-D assignment problem. Computer simulation results demonstrate the effectiveness and feasibility of this method.展开更多
The severe acute respiratory syndrome COVID-19 was discovered on December 31,2019 in China.Subsequently,many COVID-19 cases were reported in many other countries.However,some positive COVID-19 samples had been reporte...The severe acute respiratory syndrome COVID-19 was discovered on December 31,2019 in China.Subsequently,many COVID-19 cases were reported in many other countries.However,some positive COVID-19 samples had been reported earlier than those officially accepted by health authorities in other countries,such as France and Italy.Thus,it is of great importance to determine the place where SARS-CoV-2 was first transmitted to human.To this end,we analyze genomes of SARS-CoV-2 using k-mer natural vector method and compare the similarities of global SARS-CoV-2 genomes by a new natural metric.Because it is commonly accepted that SARS-CoV-2 is originated from bat coronavirus RaTG13,we only need to determine which SARS-CoV-2 genome sequence has the closest distance to bat coronavirus RaTG13 under our natural metric.From our analysis,SARS-CoV-2 most likely has already existed in other countries such as France,India,Netherland,England and United States before the outbreak at Wuhan,China.展开更多
This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated ...This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated on the reach of zone-1 relays. The approach checks the relay operation for the maximum as well as the minimum generation outputs of the power system. The proposed technique can be used for different reach setting for zone-1. Results show that it is possible to increase the coverage provided by zone-2 distance relays without causing coordination problems with the primary relays that protect the lines emanating from the remote bus. The proposed method is modified for use in an adaptive protection system. It is shown that further improvements can be achieved when settings are calculated using the proposed method and the prevailing system conditions. The proposed method and its adaptive version were applied to a part of the Power system. The simulation of the system is done by using PSCAD-EMTDC software. The simulated results are observed and compared with the conventional and proposed technique.展开更多
文摘An extension of 2-D assignment approach is proposed for measurement-to-target association for improving multiple targets vector miss distance measurement accuracy. When the multiple targets move so closely, the measurements can not be fully resolved due to finite resolution. The proposed method adopts an auction algorithm to compute the feasible measurement-to-target assignment with unresolved measurements for solving this 2-D assignment problem. Computer simulation results demonstrate the effectiveness and feasibility of this method.
基金supported by Tsinghua University Spring Breeze Fund(2020Z99CFY044)Tsinghua University start-up fundTsinghua University Education Foundation fund(042202008)。
文摘The severe acute respiratory syndrome COVID-19 was discovered on December 31,2019 in China.Subsequently,many COVID-19 cases were reported in many other countries.However,some positive COVID-19 samples had been reported earlier than those officially accepted by health authorities in other countries,such as France and Italy.Thus,it is of great importance to determine the place where SARS-CoV-2 was first transmitted to human.To this end,we analyze genomes of SARS-CoV-2 using k-mer natural vector method and compare the similarities of global SARS-CoV-2 genomes by a new natural metric.Because it is commonly accepted that SARS-CoV-2 is originated from bat coronavirus RaTG13,we only need to determine which SARS-CoV-2 genome sequence has the closest distance to bat coronavirus RaTG13 under our natural metric.From our analysis,SARS-CoV-2 most likely has already existed in other countries such as France,India,Netherland,England and United States before the outbreak at Wuhan,China.
文摘This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated on the reach of zone-1 relays. The approach checks the relay operation for the maximum as well as the minimum generation outputs of the power system. The proposed technique can be used for different reach setting for zone-1. Results show that it is possible to increase the coverage provided by zone-2 distance relays without causing coordination problems with the primary relays that protect the lines emanating from the remote bus. The proposed method is modified for use in an adaptive protection system. It is shown that further improvements can be achieved when settings are calculated using the proposed method and the prevailing system conditions. The proposed method and its adaptive version were applied to a part of the Power system. The simulation of the system is done by using PSCAD-EMTDC software. The simulated results are observed and compared with the conventional and proposed technique.
