Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for ang...Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.展开更多
This study aims to reflect the information coverage grey number and the interaction between attributes in grey relational decision making. Therefore, a multi-attribute decision method based on the grey information cov...This study aims to reflect the information coverage grey number and the interaction between attributes in grey relational decision making. Therefore, a multi-attribute decision method based on the grey information coverage interaction relational degree(GIRD) is proposed. Firstly, this paper defines the information coverage grey number, and establishes the GIRD model by using the Choquet fuzzy integral and grey relational principle. It proves that the proposed model not only is the general and unified form of the point relational degree, interval relational degree, mixed relational degree and grey fuzzy integral relational degree, but also can effectively deal with the interaction between attributes. Further,a decision making example of evaluating the industrial operation quality for 14 cities in Hunan province of China is provided to highlight the implementation, availability, and feasibility of the proposed decision model.展开更多
To obtain the stable temperature field required for growing sapphire crystals, the influence of relative positions between RF coil and crucible on the performances of sapphires produced by edge-defined film-fed growth...To obtain the stable temperature field required for growing sapphire crystals, the influence of relative positions between RF coil and crucible on the performances of sapphires produced by edge-defined film-fed growth（EFG） technique was investigated. For comparison, the crucible was located at the top（case A） and the middle（case B） of the RF coil, respectively. Furthermore, the lattice integrities were studied by the double-crystal X-ray diffraction, and the dislocations were observed under the optical microscope and atomic force microscope after corroding in molten KOH at 390 ℃. The crystals in case B exhibit better lattice integrity with smaller full width at half maximum of 29.13 rad·s, while the value in case A is 45.17 rad·s. The morphologies of dislocation etch pits in both cases show typical triangular symmetry with smooth surfaces. However, the dislocation density of 2.8×104 cm-2 in case B is only half of that in case A, and the distribution is more uniform, compared to the U-shaper in case A.展开更多
To realize high accurate control of relative position and attitude between two spacecrafts, the coupling between position and attitude must be fully considered and a more precise model should be established. This pape...To realize high accurate control of relative position and attitude between two spacecrafts, the coupling between position and attitude must be fully considered and a more precise model should be established. This paper breaks the traditional divide and conquer idea, and uses a mathematical tool, namely dual quaternion to establish the integrated 6 degree-of-freedom(6-DOF) model of relative position and attitude, which describes the coupled relative motion in a compact and efficient form and needs less information of the target. Considering the complex operation rules and the unclarity of the current relative motion model in dual quaternion, necessary mathematical foundations are given at first, followed by clear and detailed modeling process and analysis. Finally a generalized proportion-derivative(PD) controller law is designed. The simulation results show that based on the integrated model established by dual quaternion, this control law can achieve a high control accuracy of relative motion.展开更多
提出同时将透射和反射可重构智能表面(Simultaneously transmitting and reflecting reconfigurable intelligent surfaces,STAR-RIS)与通信感知一体化(Integrated sensing and communication,ISAC)系统结合,以实现全空间的通信与感知...提出同时将透射和反射可重构智能表面(Simultaneously transmitting and reflecting reconfigurable intelligent surfaces,STAR-RIS)与通信感知一体化(Integrated sensing and communication,ISAC)系统结合,以实现全空间的通信与感知。同时在STAR-RIS上应用一种低成本的传感器实现了在STAR-RIS上进行目标感知,解决了雷达感知的严重路径损耗问题。基于此,本文研究了STAR-RIS辅助位于STAR-RIS两侧的多用户多输入单输出(Multi-usermulti-input single-output,MU-MISO)以及一个位于STAR-RIS透射侧的目标的ISAC系统,旨在联合优化STAR-RIS的被动波束成形矩阵和ISAC基站处的主动波束成形矩阵,以最大化用户的通信和速率,同时满足目标感知的最低信噪比要求。为了解决优化过程中的非凸问题,提出了一种基于分式规划的块坐标上升算法,将优化变量分为几个块变量交替优化。在迭代优化后续波束成形问题上,应用了连续凸逼近和半正定松弛算法。与传统的可重构智能表面相比,仿真结果验证了在ISAC系统中部署STAR-RIS的优点。同时将所提的基于分式规划的算法与基于加权最小均方误差的算法进行了对比并验证了所提算法在提高通信和速率上的优势和有效性。展开更多
It is argued in this article to shed light on service supply chain issues associated with cloud computing by examining several interrelated questions:service supply chain architecture from service perspective; basic c...It is argued in this article to shed light on service supply chain issues associated with cloud computing by examining several interrelated questions:service supply chain architecture from service perspective; basic clouds of service supply chain and development of managerial insights into these clouds. In particular,to demonstrate how those services can be utilized and the processes involved in their utilization,a hypothetical meta-modeling service of cloud computing can be given. Moreover,the paper defines the architecture of cloud managed for SV or ISP in infrastructure of cloud computing in service supply chain:IT services,business services,business processes,which creates atomic and composite software services that are used to perform business processes with business service choreographies.展开更多
基金supported by the National Natural Science Foundation of China (12272168)the Foundation of Science and Technology on Space Intelligent Control Laboratory (HTKJ2023KL502015)。
文摘Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate system.Secondly, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.
基金supported by the National Natural Science Foundation of China(71871174,71571065,71671135)the National Social Science Fund of China(13FGL005)。
文摘This study aims to reflect the information coverage grey number and the interaction between attributes in grey relational decision making. Therefore, a multi-attribute decision method based on the grey information coverage interaction relational degree(GIRD) is proposed. Firstly, this paper defines the information coverage grey number, and establishes the GIRD model by using the Choquet fuzzy integral and grey relational principle. It proves that the proposed model not only is the general and unified form of the point relational degree, interval relational degree, mixed relational degree and grey fuzzy integral relational degree, but also can effectively deal with the interaction between attributes. Further,a decision making example of evaluating the industrial operation quality for 14 cities in Hunan province of China is provided to highlight the implementation, availability, and feasibility of the proposed decision model.
基金Project(BA2012049)supported by the Special Fund of Jiangsu Province for the Transformation of Scientific and Technological Achievements,China
文摘To obtain the stable temperature field required for growing sapphire crystals, the influence of relative positions between RF coil and crucible on the performances of sapphires produced by edge-defined film-fed growth（EFG） technique was investigated. For comparison, the crucible was located at the top（case A） and the middle（case B） of the RF coil, respectively. Furthermore, the lattice integrities were studied by the double-crystal X-ray diffraction, and the dislocations were observed under the optical microscope and atomic force microscope after corroding in molten KOH at 390 ℃. The crystals in case B exhibit better lattice integrity with smaller full width at half maximum of 29.13 rad·s, while the value in case A is 45.17 rad·s. The morphologies of dislocation etch pits in both cases show typical triangular symmetry with smooth surfaces. However, the dislocation density of 2.8×104 cm-2 in case B is only half of that in case A, and the distribution is more uniform, compared to the U-shaper in case A.
基金supported by the National Natural Science Foundation of China(6107412761427809)
文摘To realize high accurate control of relative position and attitude between two spacecrafts, the coupling between position and attitude must be fully considered and a more precise model should be established. This paper breaks the traditional divide and conquer idea, and uses a mathematical tool, namely dual quaternion to establish the integrated 6 degree-of-freedom(6-DOF) model of relative position and attitude, which describes the coupled relative motion in a compact and efficient form and needs less information of the target. Considering the complex operation rules and the unclarity of the current relative motion model in dual quaternion, necessary mathematical foundations are given at first, followed by clear and detailed modeling process and analysis. Finally a generalized proportion-derivative(PD) controller law is designed. The simulation results show that based on the integrated model established by dual quaternion, this control law can achieve a high control accuracy of relative motion.
基金funded by the National NaturalScience Foundation of China (No.70631003,No.70801024)
文摘It is argued in this article to shed light on service supply chain issues associated with cloud computing by examining several interrelated questions:service supply chain architecture from service perspective; basic clouds of service supply chain and development of managerial insights into these clouds. In particular,to demonstrate how those services can be utilized and the processes involved in their utilization,a hypothetical meta-modeling service of cloud computing can be given. Moreover,the paper defines the architecture of cloud managed for SV or ISP in infrastructure of cloud computing in service supply chain:IT services,business services,business processes,which creates atomic and composite software services that are used to perform business processes with business service choreographies.
