Situated in the semi-arid regions of North China,the Nihewan Basin documents the fluvio-lacustrine sequence and Pleistocene archaeological sites,offering an excellent opportunity to investigate human adaptation to env...Situated in the semi-arid regions of North China,the Nihewan Basin documents the fluvio-lacustrine sequence and Pleistocene archaeological sites,offering an excellent opportunity to investigate human adaptation to environmental change in East Asia,especially in North China.However,paleoenvironmental datasets from Middle Pleistocene archaeological sites are not fully understood.Focusing on the evidence from the 0.63-0.49 Ma-old site of Jijiazhuang(Nihewan Basin,North China),this paper presents the results of various environmental indicators from the site context.Moreover,it explores the links between hominin behavioral adaptations and ecological variability during the extra-long interglacial period in North China.Sedimentological features of the excavated section indicate that the site was formed in the margin of the Nihewan paleolake.Based on well-constructed pollen,sediment grain size,color reflectance,and major geochemical element analyses,five stages of environmental changes were identified during site formation.This study indicates that hominins occupied the site at the early part of Stage 2,when the Nihewan paleolake had a relatively low water level and the climate was temperate,with strong weathering intensity dominated by wooded grassland landscapes.In conclusion,the results suggest that the extra-long duration of interglacial or mild stadial climate events(MISs 15-13)in the Northern Hemisphere may have provided favorable conditions for increased technological innovations and adaptive strategies among Middle Pleistocene hominins in the Nihewan Basin even in North China.展开更多
Human activity during the Holocene in the Horqin region, northeastern China, has been widely documented. As an important proxy record of human activity, black carbon（BC） in sediments has been linked to climate chang...Human activity during the Holocene in the Horqin region, northeastern China, has been widely documented. As an important proxy record of human activity, black carbon（BC） in sediments has been linked to climate change and human adaptation. A loess-paleosol section located in south Horqin was chosen for this study. Holocene climate change and human adaptation to the environment were discussed by analyzing BC, organic carbon（OC） and other proxies. The conclusions included：（1） before 3900 cal BP, human activity was closely related to the natural environment and cultural development was dominated by climate change. For example, the rapid decline of the agrarian Hongshan culture was caused by a slight decrease in temperature at ~5000 cal BP;（2） during 3900-3200 cal BP, the heavy dependence of human societies on nature gradually lessened and the ability of those human societies to adapt to the environment was enhanced. However, the farming-dominated Lower Xiajiadian culture was nonetheless replaced by the pastoralist Upper Xiajiadian culture due to an extremely cooling event at ~3200 cal BP;（3） during the late Holocene period, the marked influence of climate change on human activity might have lessened as a result of a clear improvement in human labor skills. After this, human living styles were influenced by cultural developments rather than climate change because humans had mastered more powerful means of productivity.展开更多
The transition of human societies from high mobility to sedentary lifestyles had a profound impact on subsistence,technology,and the origin of civilization.Sedentism was influenced by various factors such as climate c...The transition of human societies from high mobility to sedentary lifestyles had a profound impact on subsistence,technology,and the origin of civilization.Sedentism was influenced by various factors such as climate change,population growth,resource pressure,and technological innovation.The Tibetan Plateau,due to its alpine and hypoxic conditions,is an ideal region to study human adaptation to extreme environments.However,the prehistoric process of sedentism on the Tibetan Plateau is unclear and the chronological sequence and driving mechanism of sedentism on the Tibetan Plateau are still controversial.Previous studies have focused on the diffusion of agriculture from low to high elevation areas,with little attention given to the role of animal resources in sedentism.Seasonality analysis using animal remains is crucial in determining whether a site was occupied year-round.To establish the seasonal calendar of animal resource utilization,it is recommended to create a database of skeletal morphology,whole genome,and proteome of contemporary Tibetan Plateau fauna to aid in the identification of animal remains from archaeological sites.Thus,intricate web of human-animal-environment relationship and the role of animal resources in human sedentism on the Tibetan Plateau can then be evaluated.展开更多
Human Adaptive Mechatronics(HAM)includes human and computer system in a closed loop.Elderly person with disabilities,normally carry out their daily routines with some assistance to move their limbs.With the short fall...Human Adaptive Mechatronics(HAM)includes human and computer system in a closed loop.Elderly person with disabilities,normally carry out their daily routines with some assistance to move their limbs.With the short fall of human care takers,mechatronics devices are used with the likes of exoskeleton and exosuits to assist them.The rehabilitation and occupational therapy equipments utilize the electromyography(EMG)signals to measure the muscle activity potential.This paper focuses on optimizing the HAM model in prediction of intended motion of upper limb with high accuracy and to increase the response time of the system.Limb characteristics extraction from EMG signal and prediction of optimal controller parameters are modeled.Time and frequency based approach of EMG signal are considered for feature extraction.The models used for estimating motion and muscle parameters from EMG signal for carrying out limb movement predictions are validated.Based on the extracted features,optimal parameters are selected by Modified Lion Optimization(MLO)for controlling the HAM system.Finally,supervised machine learning makes predictions at different points in time for individual sensing using Support Vector Neural Network(SVNN).This model is also evaluated based on optimal parameters of motion estimation and the accuracy level along with different optimization models for various upper limb movements.The proposed model of human adaptive controller predicts the limb movement by 96%accuracy.展开更多
To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusi...To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusing on both feature representation and human tracking mechanism.Feature representation describes individual by using both improved local appearance descriptors and statistical geometric parameters.The improved feature descriptors can be extracted quickly and make the human feature more discriminative.Adaptive human tracking mechanism is based on feature representation and it arranges the human image blobs in field of view into matrix.Primary appearance models are created to include the maximum inter-camera appearance information captured from different visual angles.The persons appeared in camera are first filtered by statistical geometric parameters.Then the one among the filtered persons who has the maximum matching scale with the primary models is determined to be the target person.Subsequently,the image blobs of the target person are used to update and generate new primary appearance models for the next camera,thus being robust to visual angle changes.Experimental results prove the excellence of the feature representation and show the good generalization capability of tracking mechanism as well as its robustness to condition variables.展开更多
Animal models have been extensively used as a gold standard in various biological research,including immu-nological studies.Despite high availability and ease of handling procedure,they inadequately represent complex ...Animal models have been extensively used as a gold standard in various biological research,including immu-nological studies.Despite high availability and ease of handling procedure,they inadequately represent complex interactions and unique cellular properties in humans due to inter-species genetic and microenvironmental differences which have resulted in clinical-stage failures.Organoid technology has gained enormous attention as they provide sophisticated insights about tissue architecture and functionality in miniaturized organs.In this review,we describe the use of organoid system to overcome limitations in animal-based investigations,such as physiological mismatch with humans,costly,time-consuming,and low throughput screening.Immune organoids are one of the specific advancements in organogenesis ex vivo,which can reflect human adaptive immunity with more physiologically relevant aspects.We discuss how immune organoids are established from patient-derived lymphoid tissues,as well as their characteristics and functional features to understand immune mechanisms and responses.Also,some bioengineering perspectives are considered for any potential progress of immuno-engineered organoids.展开更多
A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighbo...A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.展开更多
Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training red...Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training reduces the incidence of these secondary pathologies, but the physical effort involved in this training is such that there is poor compliance. This paper reports on the design and control of a new ＂human friendly＂ orthosis （exoskeleton）, powered by high power pneumatic Muscle Actuators （pMAs）. The combination of a highly compliant actuation system, with an intelligent embedded control mechanism which senses hip, knee, and ankle positions, velocity, acceleration and force, produces powerful yet inherently safe operation for paraplegic patients. This paper analyzes the motion of ankle, knee, and hip joints under zero loading, and loads which simulate human limb mass, showing that the use of ＂soft＂ actuators can provide a smooth user friendly motion. The application of this technology will greatly improve the rehabilitative protocols for paraplegic patients.展开更多
To commemorate 100 years since the birth of Professor Duzheng YE, this paper reviews the contribution of Ye and his research team to the development from climate to global change science in the past 30 or so years, in...To commemorate 100 years since the birth of Professor Duzheng YE, this paper reviews the contribution of Ye and his research team to the development from climate to global change science in the past 30 or so years, including：（1） the role of climate change in global change;（2） the critical time scales and predictability of global change;（3） the sensitive regions of global change—transitional zones of climate and ecosystems; and（4） orderly human activities and adaptation to global change, with a focus on the development of a proactive strategy for adaptation to such change.展开更多
This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading ef...This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.展开更多
As human beings,people coordinate movements and interact with the environment through sensory information and motor adaptation in the daily lives.Many characteristics of these interactions can be studied using optimiz...As human beings,people coordinate movements and interact with the environment through sensory information and motor adaptation in the daily lives.Many characteristics of these interactions can be studied using optimization-based models,which assume that the precise knowledge of both the sensorimotor system and its interactive environment is available for the central nervous system(CNS).However,both static and dynamic uncertainties occur inevitably in the daily movements.When these uncertainties are taken into consideration,the previously developed models based on optimization theory may fail to explain how the CNS can still coordinate human movements which are also robust with respect to the uncertainties.In order to address this problem,this paper presents a novel computational mechanism for sensorimotor control from a perspective of robust adaptive dynamic programming(RADP).Sharing some essential features of reinforcement learning,which was originally observed from mammals,the RADP model for sensorimotor control suggests that,instead of identifying the system dynamics of both the motor system and the environment,the CNS computes iteratively a robust optimal control policy using the real-time sensory data.An online learning algorithm is provided in this paper,with rigorous convergence and stability analysis.Then,it is applied to simulate several experiments reported from the past literature.By comparing the proposed numerical results with these experimentally observed data,the authors show that the proposed model can reproduce movement trajectories which are consistent with experimental observations.In addition,the RADP theory provides a unified framework that connects optimality and robustness properties in the sensorimotor system.展开更多
Owing to a unique set of attributes, human pluripotent stem cells （hPSCs） have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over l...Owing to a unique set of attributes, human pluripotent stem cells （hPSCs） have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over long term maintenance of hPSCs is pivotal in this endeavor, but hPSCs can adapt to life in culture by acquiring non-random genetic changes that render them more robust and easier to grow. In separate studies between 12.5% and 34% of hPSC lines were found to acquire chromosome abnormalities over time, with the incidence increasing with passage number. The predominant genetic changes found in hPSC lines involve changes in chromosome number and structure （particularly of chromosomes 1, 12, 17 and 20）, remi- niscent of the changes observed in cancer cells. In this review, we summarize current knowledge on the causes and consequences of aneuploidy in hPSCs and highlight the potential links with genetic changes observed in human cancers and early embryos. We point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, which allow mutations to persist in hPSC cultures. Elucidation of these mechanisms will help to design culture conditions that minimize the appearance of aneuploid hPSCs. Moreover, aneuploidy in hPSCs may provide a unique platform to analyse the driving for- ces behind the genome evolution that may eventually lead to cancerous transformation.展开更多
基金National Natural Science Foundation of China,No.42371165,No.41872029。
文摘Situated in the semi-arid regions of North China,the Nihewan Basin documents the fluvio-lacustrine sequence and Pleistocene archaeological sites,offering an excellent opportunity to investigate human adaptation to environmental change in East Asia,especially in North China.However,paleoenvironmental datasets from Middle Pleistocene archaeological sites are not fully understood.Focusing on the evidence from the 0.63-0.49 Ma-old site of Jijiazhuang(Nihewan Basin,North China),this paper presents the results of various environmental indicators from the site context.Moreover,it explores the links between hominin behavioral adaptations and ecological variability during the extra-long interglacial period in North China.Sedimentological features of the excavated section indicate that the site was formed in the margin of the Nihewan paleolake.Based on well-constructed pollen,sediment grain size,color reflectance,and major geochemical element analyses,five stages of environmental changes were identified during site formation.This study indicates that hominins occupied the site at the early part of Stage 2,when the Nihewan paleolake had a relatively low water level and the climate was temperate,with strong weathering intensity dominated by wooded grassland landscapes.In conclusion,the results suggest that the extra-long duration of interglacial or mild stadial climate events(MISs 15-13)in the Northern Hemisphere may have provided favorable conditions for increased technological innovations and adaptive strategies among Middle Pleistocene hominins in the Nihewan Basin even in North China.
基金supported by theNational Scientific Foundation of China (grant nos. 41172158, 40472094 and 40024202)"973" (grant no. 2010CB950200)+1 种基金the Strategic Priority Research program of the Chinese Academy of Sciences (grant no. XDA05120502)the Knowledge Innovation Program of the Chinese Academy of Sciences (grant no. KZCX2YW-Q1-03)
文摘Human activity during the Holocene in the Horqin region, northeastern China, has been widely documented. As an important proxy record of human activity, black carbon（BC） in sediments has been linked to climate change and human adaptation. A loess-paleosol section located in south Horqin was chosen for this study. Holocene climate change and human adaptation to the environment were discussed by analyzing BC, organic carbon（OC） and other proxies. The conclusions included：（1） before 3900 cal BP, human activity was closely related to the natural environment and cultural development was dominated by climate change. For example, the rapid decline of the agrarian Hongshan culture was caused by a slight decrease in temperature at ~5000 cal BP;（2） during 3900-3200 cal BP, the heavy dependence of human societies on nature gradually lessened and the ability of those human societies to adapt to the environment was enhanced. However, the farming-dominated Lower Xiajiadian culture was nonetheless replaced by the pastoralist Upper Xiajiadian culture due to an extremely cooling event at ~3200 cal BP;（3） during the late Holocene period, the marked influence of climate change on human activity might have lessened as a result of a clear improvement in human labor skills. After this, human living styles were influenced by cultural developments rather than climate change because humans had mastered more powerful means of productivity.
基金National Natural Science Foundation of China,No.41930323The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0601。
文摘The transition of human societies from high mobility to sedentary lifestyles had a profound impact on subsistence,technology,and the origin of civilization.Sedentism was influenced by various factors such as climate change,population growth,resource pressure,and technological innovation.The Tibetan Plateau,due to its alpine and hypoxic conditions,is an ideal region to study human adaptation to extreme environments.However,the prehistoric process of sedentism on the Tibetan Plateau is unclear and the chronological sequence and driving mechanism of sedentism on the Tibetan Plateau are still controversial.Previous studies have focused on the diffusion of agriculture from low to high elevation areas,with little attention given to the role of animal resources in sedentism.Seasonality analysis using animal remains is crucial in determining whether a site was occupied year-round.To establish the seasonal calendar of animal resource utilization,it is recommended to create a database of skeletal morphology,whole genome,and proteome of contemporary Tibetan Plateau fauna to aid in the identification of animal remains from archaeological sites.Thus,intricate web of human-animal-environment relationship and the role of animal resources in human sedentism on the Tibetan Plateau can then be evaluated.
基金This work was supported by the Deanship of Scientific Research,King Khalid University,Kingdom of Saudi Arabia under research Grant Number(R.G.P.2/100/41).
文摘Human Adaptive Mechatronics(HAM)includes human and computer system in a closed loop.Elderly person with disabilities,normally carry out their daily routines with some assistance to move their limbs.With the short fall of human care takers,mechatronics devices are used with the likes of exoskeleton and exosuits to assist them.The rehabilitation and occupational therapy equipments utilize the electromyography(EMG)signals to measure the muscle activity potential.This paper focuses on optimizing the HAM model in prediction of intended motion of upper limb with high accuracy and to increase the response time of the system.Limb characteristics extraction from EMG signal and prediction of optimal controller parameters are modeled.Time and frequency based approach of EMG signal are considered for feature extraction.The models used for estimating motion and muscle parameters from EMG signal for carrying out limb movement predictions are validated.Based on the extracted features,optimal parameters are selected by Modified Lion Optimization(MLO)for controlling the HAM system.Finally,supervised machine learning makes predictions at different points in time for individual sensing using Support Vector Neural Network(SVNN).This model is also evaluated based on optimal parameters of motion estimation and the accuracy level along with different optimization models for various upper limb movements.The proposed model of human adaptive controller predicts the limb movement by 96%accuracy.
基金funded by the Natural Science Foundation of Jiangsu Province(No.BK2012389)the National Natural Science Foundation of China(Nos.71303110,91024024)the Foundation of Graduate Innovation Center in NUAA(Nos.kfjj201471,kfjj201473)
文摘To track human across non-overlapping cameras in depression angles for applications such as multi-airplane visual human tracking and urban multi-camera surveillance,an adaptive human tracking method is proposed,focusing on both feature representation and human tracking mechanism.Feature representation describes individual by using both improved local appearance descriptors and statistical geometric parameters.The improved feature descriptors can be extracted quickly and make the human feature more discriminative.Adaptive human tracking mechanism is based on feature representation and it arranges the human image blobs in field of view into matrix.Primary appearance models are created to include the maximum inter-camera appearance information captured from different visual angles.The persons appeared in camera are first filtered by statistical geometric parameters.Then the one among the filtered persons who has the maximum matching scale with the primary models is determined to be the target person.Subsequently,the image blobs of the target person are used to update and generate new primary appearance models for the next camera,thus being robust to visual angle changes.Experimental results prove the excellence of the feature representation and show the good generalization capability of tracking mechanism as well as its robustness to condition variables.
基金supported by the NUS Presidential Young Professor-ship,Ministry of Education Tier 1,National Medical Research Council Open Fund Young Investigator Research Grant,Manufacturing,Trade and Connectivity Young Investigator Research Grant,iHT OOE award,NUS Healthy Longevity TRP Aged Mice Funding,Joint NCIS Centre Grant and NUS Centre for Cancer Research(N2CR)Seed Funding Programme,TREX Grant,PCM Seed Grant,and PREPARE Strategic Open Grant Call(Vaccines&Therapeutics Co-Operative Programme).
文摘Animal models have been extensively used as a gold standard in various biological research,including immu-nological studies.Despite high availability and ease of handling procedure,they inadequately represent complex interactions and unique cellular properties in humans due to inter-species genetic and microenvironmental differences which have resulted in clinical-stage failures.Organoid technology has gained enormous attention as they provide sophisticated insights about tissue architecture and functionality in miniaturized organs.In this review,we describe the use of organoid system to overcome limitations in animal-based investigations,such as physiological mismatch with humans,costly,time-consuming,and low throughput screening.Immune organoids are one of the specific advancements in organogenesis ex vivo,which can reflect human adaptive immunity with more physiologically relevant aspects.We discuss how immune organoids are established from patient-derived lymphoid tissues,as well as their characteristics and functional features to understand immune mechanisms and responses.Also,some bioengineering perspectives are considered for any potential progress of immuno-engineered organoids.
基金supported by the Hangzhou Key Medicine Discipline Fund for Public Health Laboratory sponsored by the Hangzhou government,National Basic Research Program of China (2010CB530303,2011-CB504703)an intramural special grant for influenza virus research from Chinese Academy of Sciences (KSZD-EW-Z-002)
文摘A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.
文摘Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training reduces the incidence of these secondary pathologies, but the physical effort involved in this training is such that there is poor compliance. This paper reports on the design and control of a new ＂human friendly＂ orthosis （exoskeleton）, powered by high power pneumatic Muscle Actuators （pMAs）. The combination of a highly compliant actuation system, with an intelligent embedded control mechanism which senses hip, knee, and ankle positions, velocity, acceleration and force, produces powerful yet inherently safe operation for paraplegic patients. This paper analyzes the motion of ankle, knee, and hip joints under zero loading, and loads which simulate human limb mass, showing that the use of ＂soft＂ actuators can provide a smooth user friendly motion. The application of this technology will greatly improve the rehabilitative protocols for paraplegic patients.
文摘To commemorate 100 years since the birth of Professor Duzheng YE, this paper reviews the contribution of Ye and his research team to the development from climate to global change science in the past 30 or so years, including：（1） the role of climate change in global change;（2） the critical time scales and predictability of global change;（3） the sensitive regions of global change—transitional zones of climate and ecosystems; and（4） orderly human activities and adaptation to global change, with a focus on the development of a proactive strategy for adaptation to such change.
基金supported by National Natural Science Foundation of China(No.51377103)the technology project of State Grid Corporation of China:Research on Multi-Level Decomposition Coordination of the Pareto Set of Multi-Objective Optimization Problem in Bulk Power System(No.SGSXDKYDWKJ2015-001)the support from State Energy Smart Grid R&D Center(SHANGHAI)
文摘This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.
基金supported in part by the US National Science Foundation Grant Nos.ECCS-1101401 and ECCS-1230040
文摘As human beings,people coordinate movements and interact with the environment through sensory information and motor adaptation in the daily lives.Many characteristics of these interactions can be studied using optimization-based models,which assume that the precise knowledge of both the sensorimotor system and its interactive environment is available for the central nervous system(CNS).However,both static and dynamic uncertainties occur inevitably in the daily movements.When these uncertainties are taken into consideration,the previously developed models based on optimization theory may fail to explain how the CNS can still coordinate human movements which are also robust with respect to the uncertainties.In order to address this problem,this paper presents a novel computational mechanism for sensorimotor control from a perspective of robust adaptive dynamic programming(RADP).Sharing some essential features of reinforcement learning,which was originally observed from mammals,the RADP model for sensorimotor control suggests that,instead of identifying the system dynamics of both the motor system and the environment,the CNS computes iteratively a robust optimal control policy using the real-time sensory data.An online learning algorithm is provided in this paper,with rigorous convergence and stability analysis.Then,it is applied to simulate several experiments reported from the past literature.By comparing the proposed numerical results with these experimentally observed data,the authors show that the proposed model can reproduce movement trajectories which are consistent with experimental observations.In addition,the RADP theory provides a unified framework that connects optimality and robustness properties in the sensorimotor system.
文摘Owing to a unique set of attributes, human pluripotent stem cells （hPSCs） have emerged as a promising cell source for regenerative medicine, disease modeling and drug discovery. Assurance of genetic stability over long term maintenance of hPSCs is pivotal in this endeavor, but hPSCs can adapt to life in culture by acquiring non-random genetic changes that render them more robust and easier to grow. In separate studies between 12.5% and 34% of hPSC lines were found to acquire chromosome abnormalities over time, with the incidence increasing with passage number. The predominant genetic changes found in hPSC lines involve changes in chromosome number and structure （particularly of chromosomes 1, 12, 17 and 20）, remi- niscent of the changes observed in cancer cells. In this review, we summarize current knowledge on the causes and consequences of aneuploidy in hPSCs and highlight the potential links with genetic changes observed in human cancers and early embryos. We point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, which allow mutations to persist in hPSC cultures. Elucidation of these mechanisms will help to design culture conditions that minimize the appearance of aneuploid hPSCs. Moreover, aneuploidy in hPSCs may provide a unique platform to analyse the driving for- ces behind the genome evolution that may eventually lead to cancerous transformation.
