The exploration of unmanned aerial vehicle(UAV)swarm systems represents a focal point in the research of multiagent systems,with the investigation of their fission-fusion behavior holding significant theoretical and p...The exploration of unmanned aerial vehicle(UAV)swarm systems represents a focal point in the research of multiagent systems,with the investigation of their fission-fusion behavior holding significant theoretical and practical value.This review systematically examines the methods for fission-fusion of UAV swarms from the perspective of multi-agent systems,encompassing the composition of UAV swarm systems and fission-fusion conditions,information interaction mechanisms,and existing fission-fusion approaches.Firstly,considering the constituent units of UAV swarms and the conditions influencing fission-fusion,this paper categorizes and introduces the UAV swarm systems.It further examines the effects and limitations of fission-fusion methods across various categories and conditions.Secondly,a comprehensive analysis of the prevalent information interaction mechanisms within UAV swarms is conducted from the perspective of information interaction structures.The advantages and limitations of various mechanisms in the context of fission-fusion behaviors are summarized and synthesized.Thirdly,this paper consolidates the existing implementation research findings related to the fission-fusion behavior of UAV swarms,identifies unresolved issues in fission-fusion research,and discusses potential solutions.Finally,the paper concludes with a comprehensive summary and systematically outlines future research opportunities.展开更多
为提升麦草秸秆碱法预处理水解液(简称碱预处理液)的可生化降解性能,本研究利用蛋清蛋白(Egg White Proteins,EWPs)热絮凝工艺脱除碱预处理液中的木质素,并与EWPs常温絮凝工艺,以及分别以氯化铁(FeCl_(3))和聚氯化铝(PAC)为絮凝剂的传...为提升麦草秸秆碱法预处理水解液(简称碱预处理液)的可生化降解性能,本研究利用蛋清蛋白(Egg White Proteins,EWPs)热絮凝工艺脱除碱预处理液中的木质素,并与EWPs常温絮凝工艺,以及分别以氯化铁(FeCl_(3))和聚氯化铝(PAC)为絮凝剂的传统絮凝工艺进行比较。结果表明,在碱预处理液浓度(以CODCr计)为8 g/L时,经EWPs热絮凝工艺处理,碱预处理液中大分子胶体木质素(以浊度计)去除率达70.6%±2.2%,小分子可溶性木质素(以总酚计)去除率达20.7±1.4%,与EWPs常温絮凝、FeCl_(3)及PAC絮凝工艺相比均有所提高。EWPs热絮凝脱除木质素的机理探究结果表明,高温会引发EWPs变性,导致其蛋白结构发生变化,促进EWPs通过疏水及氢键作用与木质素絮凝结合;在加热过程中,EWPs通过分子间氢键作用及巯基-二硫键转换反应,进一步与木质素形成大分子絮体,促进了碱预处理液中大分子木质素及其衍生物的絮聚脱除。展开更多
During the unmanned aerial vehicles （UAV） reconnaissance missions in the middle-low troposphere, the reconnaissance images are blurred and degraded due to the scattering process of aerosol under fog, haze and other ...During the unmanned aerial vehicles （UAV） reconnaissance missions in the middle-low troposphere, the reconnaissance images are blurred and degraded due to the scattering process of aerosol under fog, haze and other weather conditions, which reduce the image contrast and color fidelity. Considering the characteristics of UAV itself, this paper proposes a new algorithm for dehazing UAV reconnaissance images based on layered scattering model. The algorithm starts with the atmosphere scattering model, using the imaging distance, squint angle and other metadata acquired by the UAV. Based on the original model, a layered scattering model for dehazing is proposed. Considering the relationship between wave-length and extinction coefficient, the airlight intensity and extinction coefficient are calculated in the model. Finally, the restored images are obtained. In addition, a classification method based on Bayesian classification is used for classifica- tion of haze concentration of the image, avoiding the trouble of manual working. Then we evaluate the haze removal results according to both the subjective and objective criteria. The experimental results show that compared with the origin image, the comprehensive index of the image restored by our method increases by 282.84%, which proves that our method can obtain excellent dehazing effect.展开更多
In this paper, we consider an amplify-and-forward （AF） cooperative communication system when the channel state information （CSI） used in relay selection differs from that during data transmission, i.e., the CSI us...In this paper, we consider an amplify-and-forward （AF） cooperative communication system when the channel state information （CSI） used in relay selection differs from that during data transmission, i.e., the CSI used in relay selection is outdated. The selected relay may not be actually the best for data transmission and the outage performance of the cooperative system will deteriorate. To improve its performance, we propose a relay selection strategy based on maximum a posteriori （MAP） estimation, where relay is selected based on predicted signal-to-noise ratio （SNR）. To reduce the computation complexity, we approximate the a posteriori probability density of SNR and obtain a closed-form predicted SNR, and a relay selection strategy based on the approximate MAP estimation （RS-AMAP） is proposed. The simulation results show that this approximation leads to trivial performance loss from the perspective of outage probability. Compared with relay selection strategies given in the literature, the outage probability is reduced largely through RS-AMAP for medium-to-large transmitting powers and medium-to-high channel correlation coefficients.展开更多
基金supported by the National Natural Science Foundation of China(U20B2042).
文摘The exploration of unmanned aerial vehicle(UAV)swarm systems represents a focal point in the research of multiagent systems,with the investigation of their fission-fusion behavior holding significant theoretical and practical value.This review systematically examines the methods for fission-fusion of UAV swarms from the perspective of multi-agent systems,encompassing the composition of UAV swarm systems and fission-fusion conditions,information interaction mechanisms,and existing fission-fusion approaches.Firstly,considering the constituent units of UAV swarms and the conditions influencing fission-fusion,this paper categorizes and introduces the UAV swarm systems.It further examines the effects and limitations of fission-fusion methods across various categories and conditions.Secondly,a comprehensive analysis of the prevalent information interaction mechanisms within UAV swarms is conducted from the perspective of information interaction structures.The advantages and limitations of various mechanisms in the context of fission-fusion behaviors are summarized and synthesized.Thirdly,this paper consolidates the existing implementation research findings related to the fission-fusion behavior of UAV swarms,identifies unresolved issues in fission-fusion research,and discusses potential solutions.Finally,the paper concludes with a comprehensive summary and systematically outlines future research opportunities.
文摘为提升麦草秸秆碱法预处理水解液(简称碱预处理液)的可生化降解性能,本研究利用蛋清蛋白(Egg White Proteins,EWPs)热絮凝工艺脱除碱预处理液中的木质素,并与EWPs常温絮凝工艺,以及分别以氯化铁(FeCl_(3))和聚氯化铝(PAC)为絮凝剂的传统絮凝工艺进行比较。结果表明,在碱预处理液浓度(以CODCr计)为8 g/L时,经EWPs热絮凝工艺处理,碱预处理液中大分子胶体木质素(以浊度计)去除率达70.6%±2.2%,小分子可溶性木质素(以总酚计)去除率达20.7±1.4%,与EWPs常温絮凝、FeCl_(3)及PAC絮凝工艺相比均有所提高。EWPs热絮凝脱除木质素的机理探究结果表明,高温会引发EWPs变性,导致其蛋白结构发生变化,促进EWPs通过疏水及氢键作用与木质素絮凝结合;在加热过程中,EWPs通过分子间氢键作用及巯基-二硫键转换反应,进一步与木质素形成大分子絮体,促进了碱预处理液中大分子木质素及其衍生物的絮聚脱除。
基金supported by the National Natural Science Foundation of China(No.61450008)
文摘During the unmanned aerial vehicles （UAV） reconnaissance missions in the middle-low troposphere, the reconnaissance images are blurred and degraded due to the scattering process of aerosol under fog, haze and other weather conditions, which reduce the image contrast and color fidelity. Considering the characteristics of UAV itself, this paper proposes a new algorithm for dehazing UAV reconnaissance images based on layered scattering model. The algorithm starts with the atmosphere scattering model, using the imaging distance, squint angle and other metadata acquired by the UAV. Based on the original model, a layered scattering model for dehazing is proposed. Considering the relationship between wave-length and extinction coefficient, the airlight intensity and extinction coefficient are calculated in the model. Finally, the restored images are obtained. In addition, a classification method based on Bayesian classification is used for classifica- tion of haze concentration of the image, avoiding the trouble of manual working. Then we evaluate the haze removal results according to both the subjective and objective criteria. The experimental results show that compared with the origin image, the comprehensive index of the image restored by our method increases by 282.84%, which proves that our method can obtain excellent dehazing effect.
基金National Basic Research Program of China(No.2010CB731803)
文摘In this paper, we consider an amplify-and-forward （AF） cooperative communication system when the channel state information （CSI） used in relay selection differs from that during data transmission, i.e., the CSI used in relay selection is outdated. The selected relay may not be actually the best for data transmission and the outage performance of the cooperative system will deteriorate. To improve its performance, we propose a relay selection strategy based on maximum a posteriori （MAP） estimation, where relay is selected based on predicted signal-to-noise ratio （SNR）. To reduce the computation complexity, we approximate the a posteriori probability density of SNR and obtain a closed-form predicted SNR, and a relay selection strategy based on the approximate MAP estimation （RS-AMAP） is proposed. The simulation results show that this approximation leads to trivial performance loss from the perspective of outage probability. Compared with relay selection strategies given in the literature, the outage probability is reduced largely through RS-AMAP for medium-to-large transmitting powers and medium-to-high channel correlation coefficients.
