The aim of this study was to carry out a dynamic simulation of the energy and environmental performance of a built space system, with a view to assessing its energy and environmental class. The use of a simulation and...The aim of this study was to carry out a dynamic simulation of the energy and environmental performance of a built space system, with a view to assessing its energy and environmental class. The use of a simulation and modeling tool, supported by various methodological references, formed the basis of our approach. Adopting a systemic perspective, we described the structural and functional aspects of the systems making up built spaces, as well as the associated energy flows. Our approach was also based on a typology, taking into account typical days, structural and functional configurations at different scales and angles of observation. The analysis tool we developed in Java was applied to the built space system of the Patte d’Oie university campus in Ouagadougou. Annual electricity consumption was measured at 124387.34 kWh, closely aligned with the average annual electricity bill (125224.31 kWh), with a maximum relative deviation of 1%, followed by a carbon emission balance of 58337.66 kg eq CO<sub>2</sub> per year. This validation confirmed the effectiveness of our tool. In addition, following the analysis of electricity consumption using our tool, the university campus was classified in energy class B and environmental class C. These results will be based on the emission factors of the energy mix of the West African Economic and Monetary Union (WAEMU) territory, with particular emphasis on Burkina Faso.展开更多
This paper discusses the major problems in urban green space system (UGSS) planning at both general and special planning levels in China. At general planning level, the problems of the UGSS are mainly from the ignor...This paper discusses the major problems in urban green space system (UGSS) planning at both general and special planning levels in China. At general planning level, the problems of the UGSS are mainly from the ignorance in the characteristics of urban nature spaces and the limitation factors of the urban planning system. Great importance is attached to the green spaces in the built area of city, but the green spaces in surrounding areas of the city is unnoticed. Furthermore, because the area of UGSS planning is strictly limited by the administrative zoning, the green space system loses its integrity and rationality in spatial patterns. The schedules of urban development planning mismatched the paces and progresses of the ecological restoration cycles. At special plan level, the problem of the UGSS in China is that the green spaces quantity was over emphasized but the rationality of their layouts is neglected.. Meanwhile, the requirement of the spatial structures and the green spaces layouts to balance between the urban development and the natural ecological environments is often ignored. With regard to the layouts in the UGSS planning practices, the existing problems are the compromising to the existing land-uses, the 'filling in' approach to plan green spaces and an over-emphasis on the layout patterns.展开更多
The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as disco...The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.展开更多
Discusses in detail the deploying strategies and feature of the motion of the Tethered Space System and the effects of some parameters, such as the property and initial length of the tether, the perturbation of the at...Discusses in detail the deploying strategies and feature of the motion of the Tethered Space System and the effects of some parameters, such as the property and initial length of the tether, the perturbation of the atmosphere, the ellipse of the orbit and the mass distribution of the system and points out the deploying strategy is based on the controlling of tension and the length of tether. And concludes from the computer simulation results of a tethered atmosphere probing satellite deployment that the deploying strategy presented does work well.展开更多
Currently, urban Green Space Systems in China show fragile ecological conditions, the overseas Green Infrastructure is a new idea to construct urban green ecological spaces. Typical Green Infrastructure construction c...Currently, urban Green Space Systems in China show fragile ecological conditions, the overseas Green Infrastructure is a new idea to construct urban green ecological spaces. Typical Green Infrastructure construction cases in the U. K., such as London greenbelt, park system, green corridor, green chain and Green Grid were studied to analyze problems of China urban Green Space System planning, construction, and management, so as to propose suggestions for improving ecological functions of the urban Green Space System.展开更多
The concept of urban green space system planning was proposed after analyzing the background of compiling Guangzhou green space system planning and current situation of local green spaces,i.e. design landscape pattern...The concept of urban green space system planning was proposed after analyzing the background of compiling Guangzhou green space system planning and current situation of local green spaces,i.e. design landscape pattern of Guangzhou City during urban agglomeration of the Pearl River Delta,and highlight Lingnan cultures(Lingnan refers to south of the Five Ridges) and features of "Flower City"(another name of Guangzhou). Key points of planning are protecting ecological barriers in the north,improving urban garden structure in the center,using wetland reasonably in the south,to maintain integrality and continuity of the landscape pattern.展开更多
Characteristic urban construction has already become a trend of modern social development,in this context,components of characteristic urban green spaces,and ways of demonstrating features of urban green space system ...Characteristic urban construction has already become a trend of modern social development,in this context,components of characteristic urban green spaces,and ways of demonstrating features of urban green space system were analyzed.Shuangcheng City in Heilongjiang Province was taken for example to analyze planning objectives and principles of characteristic urban green space system.Moreover,the green space layout of "A Hundred Years Old Castle,A Hundred of Enterprises and A Hundred of Gardens" was introduced.It was proposed that green space system planning suited to the development features and ecological conditions of the city should be developed from the perspective of greater regional environment,historical and cultural deposits,urban development pattern and lifestyle of the locals,so as to create urban green space system with regional features.展开更多
In the context of the rapid development of urbanization in China, the development of emerging town shows a high-speed prosperity. This paper describes current situation of the emerging urban green space system and ana...In the context of the rapid development of urbanization in China, the development of emerging town shows a high-speed prosperity. This paper describes current situation of the emerging urban green space system and analyzes different characteristics between current green spaces and the old city or existing urban green space. Considering green space system planning in the downtown area of Gu'an County, advantages of the "network + patch" layout for green space systems in emerging towns are summarized to explore a green space structure suited to these towns.展开更多
Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local are...Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local area from the perspective of landscape ecology, and then established the landscape ecology-oriented ecological network construction, restructured green paces in Wanzhou District using the landscape composition of "patch–corridor–matrix", and connected the scattered green patches using green corridors, so as to form a reasonable ecological network of green spaces.展开更多
Ecosystem of Yan'an City is being faced with serious problems such as increasing pressure of protecting ecological elements,and contradictions in utilization of ecological spaces.To enhance supervision over region...Ecosystem of Yan'an City is being faced with serious problems such as increasing pressure of protecting ecological elements,and contradictions in utilization of ecological spaces.To enhance supervision over regional ecological resources,guide the orderly expansion of urban spaces,construct a stable eco-security pattern for sustainable development of the city,and create an urban environment favorable for living and working,this study follows the principles of "ecology on the priority,landscape continuity,diversity,optimization of layout,and sustainability".By analyzing distribution features of ecological resources in Yan'an City,considering rules of its urban space expansion,and studying the "ring-wedge-network" spatial pattern of its ecological green spaces,this study is to build an ecological network with a complete spatial system,definite ecological zoning and characteristic landscapes in which ecological elements are protected comprehensively,ecological conservation,restoration and construction promoted simultaneously.展开更多
In this paper,we design a spatial modulation based orthogonal time frequency space(SMOTFS)system to achieve improved transmission reliability and meet the high transmission rate and highspeed demands of future mobile ...In this paper,we design a spatial modulation based orthogonal time frequency space(SMOTFS)system to achieve improved transmission reliability and meet the high transmission rate and highspeed demands of future mobile communications,which fully utilizes the characteristics of spatial modulation(SM)and orthogonal time frequency space(OTFS)transmission.The detailed system design and signal processing of the SM-OTFS system have been presented.The closed-form expressions of the average symbol error rate(ASER)and average bit error rate(ABER)of the SM-OTFS system have been derived over the delay-Doppler channel with the help of the union bounding technique and moment-generating function(MGF).Meanwhile,the system complexity has been evaluated.Numerical results verify the correctness of the theoretical ASER and ABER analysis of the SM-OTFS system in the high signal-to-noise ratio(SNR)regions and also show that the SM-OTFS system outperforms the traditional SM based orthogonal frequency division multiplexing(SM-OFDM)system with limited complexity increase under mobile conditions,especially in high mobility scenarios.展开更多
The present research relies on a cascade control approach through the Monte-Carlo based method in the presence of uncertainties to evaluate the performance of the real overactuated space systems.A number of potential ...The present research relies on a cascade control approach through the Monte-Carlo based method in the presence of uncertainties to evaluate the performance of the real overactuated space systems.A number of potential investigations in this area are first considered to prepare an idea with respect to state-of-the-art.The insight proposed here is organized to present attitude cascade control approach including the low thrust in connection with the high thrust to be implemented,while the aforementioned Monte-Carlo based method is carried out to guarantee the approach performance.It is noted that the investigated outcomes are efficient to handle a class of space systems presented via the center of mass and the moments of inertial.And also a number of profiles for the thrust vector and the misalignments as the disturbances all vary in its span of nominal variations.The acquired results are finally analyzed in line with some well-known benchmarks to verify the approach efficiency.The key core of finding in the research is to propose a novel 3-axis control approach to deal with all the mentioned uncertainties of space systems under control,in a synchronous manner,as long as the appropriate models in the low-high thrusts are realized.展开更多
This paper is aimed at studying the environmental degradation of densely built-up areas in the process of urbanization in China. In consideration of the severe environmental conditions of the densely built-up areas, s...This paper is aimed at studying the environmental degradation of densely built-up areas in the process of urbanization in China. In consideration of the severe environmental conditions of the densely built-up areas, such as the lack of green space and open space, ecological disturbance in some areas, poor landscape quality, this paper focused on the ecological space optimization in the process of urban renewal. Firstly, theories related to this field were analyzed, and a comprehensive ecological efficiency evaluation system was established based on disciplines such as urban ecology, landscape ecology, urban sociology, behavioral psychology, biology, urban planning and design. Secondly, this system was used to judge the ecological efficiency of typical blocks on GIS platform and to find out the key spatial nodes that need to be updated. Thirdly, in different cases, space optimization projects with different theories were designed, and the spatial model of influence was used to comprehensively evaluate their ecological efficiency. Finally, the parameters under different conditions were corrected to get a systematic system for evaluating the green space system in densely built-up areas. Due to the lack of understanding of the ecological function of green space in the past, the environmental condition of densely built-up areas is not good. Therefore, the most important task of urban organic renewal is ecological restoration. In this paper, the exploration is based on the reservation for built-up areas to avoid repeated reconstruction and interference. Authors of this paper tried to find out a way to rebuild green space system that performed more complex functions with limited spatial resources. The application of "micro-transformation" of green space system in densely built-up areas turns out to improve the quality of landscape while reducing the construction cost.展开更多
目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,...目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。展开更多
目的梳理国内多发伤急救相关研究文献,分析研究现状、热点和趋势,为我国多发伤急救研究提供借鉴和指导。方法检索中国知网数据库中2011—2021年关于多发伤急救的相关文献,使用Cite Space 6.1.R3可视化软件对该领域的年发文量、机构、作...目的梳理国内多发伤急救相关研究文献,分析研究现状、热点和趋势,为我国多发伤急救研究提供借鉴和指导。方法检索中国知网数据库中2011—2021年关于多发伤急救的相关文献,使用Cite Space 6.1.R3可视化软件对该领域的年发文量、机构、作者、关键词进行分析。结果最终纳入多发伤急救研究文献2519篇,整体发文数量较平稳,以2016年为小高峰;发文量最高的机构是华中科技大学附属同济医院。多发伤急救研究热点包括院前急救、并发症护理、风险因素分析和预后效果评估,研究前沿包括不同多发伤人群的诊断、治疗、手术和护理体会等方面。结论本文通过可视化分析国内多发伤急救研究的热点及趋势,指明了多发伤目前研究存在的问题和未来研究发展的方向,为进一步完善多发伤急救卫生服务和管理体系提供指导。展开更多
This paper first describes a binary Low-Density Parity-Check(LDPC)-coded Probabilistic Shaping(PS)scheme for Multiple-Input Multiple-Output(MIMO)systems based on Signal Space Diversity(SSD).Second,a Nonbinary(NB)LDPC-...This paper first describes a binary Low-Density Parity-Check(LDPC)-coded Probabilistic Shaping(PS)scheme for Multiple-Input Multiple-Output(MIMO)systems based on Signal Space Diversity(SSD).Second,a Nonbinary(NB)LDPC-coded PS scheme for MIMO systems based on SSD is proposed.The first scheme can be used to obtain a shaping gain,whereas the second can also realize a coding gain.The theoretical average mutual information of the optimized rotated quadrature amplitude modulation constellations is analyzed and the simulated error per-formance with 22 and 44 MIMO schemes is investigated.The theoretical average mutual information analysis and simulation results show that the proposed NB LDPC-coded PS scheme for MIMO systems based on SSD is reliable and robust,and is therefore suitable for future wireless communication systems.展开更多
为了解国内外近10年护理不良事件的研究热点与前沿,为医院管理和临床护士提供参考,保障患者安全,通过检索中国期刊全文数据库(CNKI)和Web of Science(WOS)数据库,检索时限为2012年1月—2022年8月,导入CiteSpace进行可视化分析。研究显示...为了解国内外近10年护理不良事件的研究热点与前沿,为医院管理和临床护士提供参考,保障患者安全,通过检索中国期刊全文数据库(CNKI)和Web of Science(WOS)数据库,检索时限为2012年1月—2022年8月,导入CiteSpace进行可视化分析。研究显示,从发文量看,国内外学者对护理不良事件的关注度整体较高,可视化分析结果并未发现作者之间、机构之间的联系。未来减少护理不良事件的方法一定会越来越紧贴科学技术,越来越多的新型信息化平台、App等会用于医疗行业,降低护理不良事件预防的难度,但护理人员仍要重视护理安全。展开更多
高质量教师是高质量教育发展的中坚力量。教师信念作为教师专业素养构成的关键要素,对促进教师专业发展、提升教师质量具有重要作用与影响。为借鉴国际体育教师信念研究的成果与经验,促进国内对体育教师信念的研究,研究利用CiteSpace软...高质量教师是高质量教育发展的中坚力量。教师信念作为教师专业素养构成的关键要素,对促进教师专业发展、提升教师质量具有重要作用与影响。为借鉴国际体育教师信念研究的成果与经验,促进国内对体育教师信念的研究,研究利用CiteSpace软件,对Web of Science核心合集数据库中1960—2022年的英文文献进行可视化研究。发现:体育教师信念研究高潮出现于2021年,载文数量最多的期刊是Journal of Teaching in Physical Education;研究中心度最高的国家是美国,核心圈层的代表学者是Richards KAR、Kulinna PH和Curtner-smith MD等人;研究热点趋势集中于体力活动促进、职业社会化、批判性教学法、职前体育教师、专业发展等方面。启示:国内未来研究应重点关注体育教师信念对课程改革的影响以及促进职前、职后阶段体育教师信念的发展。展开更多
Orthogonal time-frequency space(OTFS),which exhibits beneficial advantages in high-mobility scenarios,has been considered as a promising technology in future wireless communication systems.In this paper,a universal mo...Orthogonal time-frequency space(OTFS),which exhibits beneficial advantages in high-mobility scenarios,has been considered as a promising technology in future wireless communication systems.In this paper,a universal model for OTFS systems with generalized waveform has been developed.Furthermore,the average bit error probability(ABEP)upper bounds of the optimal maximum likelihood(ML)detector are first derived for OTFS systems with generalized waveforms.Specifically,for OTFS systems with the ideal waveform,we elicit the ABEP bound by recombining the transmitted signal and the received signal.For OTFS systems with practical waveforms,a universal ABEP upper bound expression is derived using moment-generating function(MGF),which is further extended to MIMO-OTFS systems.Numerical results validate that our theoretical ABEP upper bounds are concur with the simulation performance achieved by ML detectors.展开更多
文摘The aim of this study was to carry out a dynamic simulation of the energy and environmental performance of a built space system, with a view to assessing its energy and environmental class. The use of a simulation and modeling tool, supported by various methodological references, formed the basis of our approach. Adopting a systemic perspective, we described the structural and functional aspects of the systems making up built spaces, as well as the associated energy flows. Our approach was also based on a typology, taking into account typical days, structural and functional configurations at different scales and angles of observation. The analysis tool we developed in Java was applied to the built space system of the Patte d’Oie university campus in Ouagadougou. Annual electricity consumption was measured at 124387.34 kWh, closely aligned with the average annual electricity bill (125224.31 kWh), with a maximum relative deviation of 1%, followed by a carbon emission balance of 58337.66 kg eq CO<sub>2</sub> per year. This validation confirmed the effectiveness of our tool. In addition, following the analysis of electricity consumption using our tool, the university campus was classified in energy class B and environmental class C. These results will be based on the emission factors of the energy mix of the West African Economic and Monetary Union (WAEMU) territory, with particular emphasis on Burkina Faso.
文摘This paper discusses the major problems in urban green space system (UGSS) planning at both general and special planning levels in China. At general planning level, the problems of the UGSS are mainly from the ignorance in the characteristics of urban nature spaces and the limitation factors of the urban planning system. Great importance is attached to the green spaces in the built area of city, but the green spaces in surrounding areas of the city is unnoticed. Furthermore, because the area of UGSS planning is strictly limited by the administrative zoning, the green space system loses its integrity and rationality in spatial patterns. The schedules of urban development planning mismatched the paces and progresses of the ecological restoration cycles. At special plan level, the problem of the UGSS in China is that the green spaces quantity was over emphasized but the rationality of their layouts is neglected.. Meanwhile, the requirement of the spatial structures and the green spaces layouts to balance between the urban development and the natural ecological environments is often ignored. With regard to the layouts in the UGSS planning practices, the existing problems are the compromising to the existing land-uses, the 'filling in' approach to plan green spaces and an over-emphasis on the layout patterns.
基金Sponsored by Hainan Provincial Natural Science Fund(411095)Hainan Provincial Philosophical and Social Science Planning Program(HNSK(JD)11-1)Sanya University-Local Goverment Science&Technology Cooperation Program(2013YD53)
文摘The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.
文摘Discusses in detail the deploying strategies and feature of the motion of the Tethered Space System and the effects of some parameters, such as the property and initial length of the tether, the perturbation of the atmosphere, the ellipse of the orbit and the mass distribution of the system and points out the deploying strategy is based on the controlling of tension and the length of tether. And concludes from the computer simulation results of a tethered atmosphere probing satellite deployment that the deploying strategy presented does work well.
基金Supported by General Program of Yunnan Provincial Applied Basic Research(2009ZC075M):Study on Yunnan Town’s Characteristic Landscape and Ecological Security Pattern based on GIS
文摘Currently, urban Green Space Systems in China show fragile ecological conditions, the overseas Green Infrastructure is a new idea to construct urban green ecological spaces. Typical Green Infrastructure construction cases in the U. K., such as London greenbelt, park system, green corridor, green chain and Green Grid were studied to analyze problems of China urban Green Space System planning, construction, and management, so as to propose suggestions for improving ecological functions of the urban Green Space System.
文摘The concept of urban green space system planning was proposed after analyzing the background of compiling Guangzhou green space system planning and current situation of local green spaces,i.e. design landscape pattern of Guangzhou City during urban agglomeration of the Pearl River Delta,and highlight Lingnan cultures(Lingnan refers to south of the Five Ridges) and features of "Flower City"(another name of Guangzhou). Key points of planning are protecting ecological barriers in the north,improving urban garden structure in the center,using wetland reasonably in the south,to maintain integrality and continuity of the landscape pattern.
文摘Characteristic urban construction has already become a trend of modern social development,in this context,components of characteristic urban green spaces,and ways of demonstrating features of urban green space system were analyzed.Shuangcheng City in Heilongjiang Province was taken for example to analyze planning objectives and principles of characteristic urban green space system.Moreover,the green space layout of "A Hundred Years Old Castle,A Hundred of Enterprises and A Hundred of Gardens" was introduced.It was proposed that green space system planning suited to the development features and ecological conditions of the city should be developed from the perspective of greater regional environment,historical and cultural deposits,urban development pattern and lifestyle of the locals,so as to create urban green space system with regional features.
文摘In the context of the rapid development of urbanization in China, the development of emerging town shows a high-speed prosperity. This paper describes current situation of the emerging urban green space system and analyzes different characteristics between current green spaces and the old city or existing urban green space. Considering green space system planning in the downtown area of Gu'an County, advantages of the "network + patch" layout for green space systems in emerging towns are summarized to explore a green space structure suited to these towns.
文摘Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local area from the perspective of landscape ecology, and then established the landscape ecology-oriented ecological network construction, restructured green paces in Wanzhou District using the landscape composition of "patch–corridor–matrix", and connected the scattered green patches using green corridors, so as to form a reasonable ecological network of green spaces.
文摘Ecosystem of Yan'an City is being faced with serious problems such as increasing pressure of protecting ecological elements,and contradictions in utilization of ecological spaces.To enhance supervision over regional ecological resources,guide the orderly expansion of urban spaces,construct a stable eco-security pattern for sustainable development of the city,and create an urban environment favorable for living and working,this study follows the principles of "ecology on the priority,landscape continuity,diversity,optimization of layout,and sustainability".By analyzing distribution features of ecological resources in Yan'an City,considering rules of its urban space expansion,and studying the "ring-wedge-network" spatial pattern of its ecological green spaces,this study is to build an ecological network with a complete spatial system,definite ecological zoning and characteristic landscapes in which ecological elements are protected comprehensively,ecological conservation,restoration and construction promoted simultaneously.
基金in part by the National Natural Science Foundation of China under Grant 61771291,Grant 61671278in part by the Key Research and Development Project of Shandong Province under Grant 2018GGX101009,Grant 2019TSLH0202,Grant 2020CXGC010109+1 种基金in part by the National Nature Science Foundation of China for Excellent Young Scholars under Grant 61622111in part by the Project of International Cooperation and Exchanges NSFC under Grant 61860206005.
文摘In this paper,we design a spatial modulation based orthogonal time frequency space(SMOTFS)system to achieve improved transmission reliability and meet the high transmission rate and highspeed demands of future mobile communications,which fully utilizes the characteristics of spatial modulation(SM)and orthogonal time frequency space(OTFS)transmission.The detailed system design and signal processing of the SM-OTFS system have been presented.The closed-form expressions of the average symbol error rate(ASER)and average bit error rate(ABER)of the SM-OTFS system have been derived over the delay-Doppler channel with the help of the union bounding technique and moment-generating function(MGF).Meanwhile,the system complexity has been evaluated.Numerical results verify the correctness of the theoretical ASER and ABER analysis of the SM-OTFS system in the high signal-to-noise ratio(SNR)regions and also show that the SM-OTFS system outperforms the traditional SM based orthogonal frequency division multiplexing(SM-OFDM)system with limited complexity increase under mobile conditions,especially in high mobility scenarios.
文摘The present research relies on a cascade control approach through the Monte-Carlo based method in the presence of uncertainties to evaluate the performance of the real overactuated space systems.A number of potential investigations in this area are first considered to prepare an idea with respect to state-of-the-art.The insight proposed here is organized to present attitude cascade control approach including the low thrust in connection with the high thrust to be implemented,while the aforementioned Monte-Carlo based method is carried out to guarantee the approach performance.It is noted that the investigated outcomes are efficient to handle a class of space systems presented via the center of mass and the moments of inertial.And also a number of profiles for the thrust vector and the misalignments as the disturbances all vary in its span of nominal variations.The acquired results are finally analyzed in line with some well-known benchmarks to verify the approach efficiency.The key core of finding in the research is to propose a novel 3-axis control approach to deal with all the mentioned uncertainties of space systems under control,in a synchronous manner,as long as the appropriate models in the low-high thrusts are realized.
基金Sponsored by National Natural Science Fund of China(51578454)
文摘This paper is aimed at studying the environmental degradation of densely built-up areas in the process of urbanization in China. In consideration of the severe environmental conditions of the densely built-up areas, such as the lack of green space and open space, ecological disturbance in some areas, poor landscape quality, this paper focused on the ecological space optimization in the process of urban renewal. Firstly, theories related to this field were analyzed, and a comprehensive ecological efficiency evaluation system was established based on disciplines such as urban ecology, landscape ecology, urban sociology, behavioral psychology, biology, urban planning and design. Secondly, this system was used to judge the ecological efficiency of typical blocks on GIS platform and to find out the key spatial nodes that need to be updated. Thirdly, in different cases, space optimization projects with different theories were designed, and the spatial model of influence was used to comprehensively evaluate their ecological efficiency. Finally, the parameters under different conditions were corrected to get a systematic system for evaluating the green space system in densely built-up areas. Due to the lack of understanding of the ecological function of green space in the past, the environmental condition of densely built-up areas is not good. Therefore, the most important task of urban organic renewal is ecological restoration. In this paper, the exploration is based on the reservation for built-up areas to avoid repeated reconstruction and interference. Authors of this paper tried to find out a way to rebuild green space system that performed more complex functions with limited spatial resources. The application of "micro-transformation" of green space system in densely built-up areas turns out to improve the quality of landscape while reducing the construction cost.
文摘目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。
文摘目的梳理国内多发伤急救相关研究文献,分析研究现状、热点和趋势,为我国多发伤急救研究提供借鉴和指导。方法检索中国知网数据库中2011—2021年关于多发伤急救的相关文献,使用Cite Space 6.1.R3可视化软件对该领域的年发文量、机构、作者、关键词进行分析。结果最终纳入多发伤急救研究文献2519篇,整体发文数量较平稳,以2016年为小高峰;发文量最高的机构是华中科技大学附属同济医院。多发伤急救研究热点包括院前急救、并发症护理、风险因素分析和预后效果评估,研究前沿包括不同多发伤人群的诊断、治疗、手术和护理体会等方面。结论本文通过可视化分析国内多发伤急救研究的热点及趋势,指明了多发伤目前研究存在的问题和未来研究发展的方向,为进一步完善多发伤急救卫生服务和管理体系提供指导。
基金supported by Fundamental Research Program of Shanxi Province(202203021212159).
文摘This paper first describes a binary Low-Density Parity-Check(LDPC)-coded Probabilistic Shaping(PS)scheme for Multiple-Input Multiple-Output(MIMO)systems based on Signal Space Diversity(SSD).Second,a Nonbinary(NB)LDPC-coded PS scheme for MIMO systems based on SSD is proposed.The first scheme can be used to obtain a shaping gain,whereas the second can also realize a coding gain.The theoretical average mutual information of the optimized rotated quadrature amplitude modulation constellations is analyzed and the simulated error per-formance with 22 and 44 MIMO schemes is investigated.The theoretical average mutual information analysis and simulation results show that the proposed NB LDPC-coded PS scheme for MIMO systems based on SSD is reliable and robust,and is therefore suitable for future wireless communication systems.
文摘为了解国内外近10年护理不良事件的研究热点与前沿,为医院管理和临床护士提供参考,保障患者安全,通过检索中国期刊全文数据库(CNKI)和Web of Science(WOS)数据库,检索时限为2012年1月—2022年8月,导入CiteSpace进行可视化分析。研究显示,从发文量看,国内外学者对护理不良事件的关注度整体较高,可视化分析结果并未发现作者之间、机构之间的联系。未来减少护理不良事件的方法一定会越来越紧贴科学技术,越来越多的新型信息化平台、App等会用于医疗行业,降低护理不良事件预防的难度,但护理人员仍要重视护理安全。
文摘高质量教师是高质量教育发展的中坚力量。教师信念作为教师专业素养构成的关键要素,对促进教师专业发展、提升教师质量具有重要作用与影响。为借鉴国际体育教师信念研究的成果与经验,促进国内对体育教师信念的研究,研究利用CiteSpace软件,对Web of Science核心合集数据库中1960—2022年的英文文献进行可视化研究。发现:体育教师信念研究高潮出现于2021年,载文数量最多的期刊是Journal of Teaching in Physical Education;研究中心度最高的国家是美国,核心圈层的代表学者是Richards KAR、Kulinna PH和Curtner-smith MD等人;研究热点趋势集中于体力活动促进、职业社会化、批判性教学法、职前体育教师、专业发展等方面。启示:国内未来研究应重点关注体育教师信念对课程改革的影响以及促进职前、职后阶段体育教师信念的发展。
基金supported in part by the National Key Research and Development Program of China under Grant 2021YFB2900502the National Science Foundation of China under Grant 62001179the Fundamental Research Funds for the Central Universities under Grant 2020kfyXJJS111。
文摘Orthogonal time-frequency space(OTFS),which exhibits beneficial advantages in high-mobility scenarios,has been considered as a promising technology in future wireless communication systems.In this paper,a universal model for OTFS systems with generalized waveform has been developed.Furthermore,the average bit error probability(ABEP)upper bounds of the optimal maximum likelihood(ML)detector are first derived for OTFS systems with generalized waveforms.Specifically,for OTFS systems with the ideal waveform,we elicit the ABEP bound by recombining the transmitted signal and the received signal.For OTFS systems with practical waveforms,a universal ABEP upper bound expression is derived using moment-generating function(MGF),which is further extended to MIMO-OTFS systems.Numerical results validate that our theoretical ABEP upper bounds are concur with the simulation performance achieved by ML detectors.