The Experts below are selected from a list of 1860 Experts worldwide ranked by ideXlab platform
Jie Huang - One of the best experts on this subject based on the ideXlab platform.
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a generic internal model for robust output regulation problem for plants subject to an uncertain Exosystem
International Conference on Control and Automation, 2019Co-Authors: Jie HuangAbstract:The canonical internal model is the key technique for handling the robust output regulation problem of systems with an uncertain Exosystem. However, the output mapping of this internal model relies on the uncertain parameters of the Exosystem. These uncertain parameters in the output mapping have to be further estimated using the adaptive control technique, which complicates the design of the overall control law. In this paper, we consider constructing a so-called generic internal model (gIM) which has the same form as the canonical internal model but with an output mapping independent of the uncertain parameters of the Exosystem. With such an internal model, the robust output regulation problem for systems with an uncertain Exosystem can be solved solely by the robust control approach, which is much simpler than the control law based on the adaptive control approach. We give conditions for constructing such gIMs.
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Speed tracking control of surface-mounted permanent-magnet synchronous motor with unknown Exosystem
International Journal of Robust and Nonlinear Control, 2014Co-Authors: Zhaowu Ping, Jie HuangAbstract:Summary The surface-mounted permanent-magnet synchronous motor is a two-input, two-output nonlinear system. The multi-input, multi-output nature of the system has posed some specific challenges to various control methods. Recently, the robust output regulation problem of the system subject to a known neutrally stable Exosystem was studied. The problem came down to a global robust stabilization problem of an augmented system composed of the original plant and an internal model. In this paper, we will further study the robust output regulation problem of the system subject to an unknown neutrally stable Exosystem. Like in the case where the Exosystem is known, the current problem can be solved by globally stabilizing an augmented system. But unlike in the case where the Exosystem is known, the augmented system takes a much more complicated form because of uncertainty in the Exosystem than the case where the Exosystem is known. In particular, the dynamic uncertainty in the current augmented system contains linearly parameterized uncertainty, and hence is not input-to-state stable. By utilizing some dynamic coordinate transformation technique, and combining some robust control and adaptive control techniques, we will solve the problem via a recursive approach. Copyright © 2014 John Wiley & Sons, Ltd.
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a control problem of surface mounted pm synchronous motor with unknown Exosystem
American Control Conference, 2013Co-Authors: Zhaowu Ping, Jie HuangAbstract:The surface-mounted PM synchronous motor is a two-input, two-output nonlinear system. Recently, the robust output regulation problem of this motor system subject to a known neutrally stable Exosystem was studied. The problem came down to a global robust stabilization problem of an augmented system composed of the original plant and an internal model. In this paper, we will further study the robust output regulation problem of the motor system subject to an unknown neutrally stable Exosystem. Like the case where the Exosystem is known, the current problem can be solved by globally stabilizing an augmented system. But unlike the case where the Exosystem is known, the augmented system takes a much more complicated form due to uncertainty in the Exosystem than the case where the Exosystem is known. In particular, the dynamic uncertainty in the current augmented system is not input-to-state stable. By utilizing some dynamic coordinate transformation technique, and combining some robust control and adaptive control techniques, we will solve the problem via a recursive approach.
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Global Robust Output Regulation of Nonlinear Systems with a Nonlinear Exosystem
2011Co-Authors: Xi Yang, Jie HuangAbstract:The global robust output regulation problem for nonlinear plants subject to nonlinear Exosystems has been a challenging problem and has not been well addressed. The main difficulty lies in finding a suitable internal model. In this paper, we first propose a new class of internal models which is guaranteed to exist under the generalized immersion condition [2]. An advantage of this internal model is that it is zero input globally asymptotically stable. This fact will facilitate the global stabilization of the augmented system associated with the given plant and the internal model. Then we will further utilize this class of internal models to solve the global robust output regulation problem for output feedback systems with a nonlinear Exosystem.
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New results on robust output regulation of nonlinear systems with a nonlinear Exosystem
International Journal of Robust and Nonlinear Control, 2011Co-Authors: Xi Yang, Jie HuangAbstract:SUMMARY The global robust output regulation problem for nonlinear plants subject to nonlinear Exosystems has been a challenging problem and has not been well addressed. The main difficulty lies in finding a suitable internal model. The existing internal model for handling the nonlinear Exosystem is not zero input globally asymptotically stable, and can only guarantee a local solution for the output regulation problem. In this paper, we first propose a new class of internal models, which is guaranteed to exist under the generalized immersion condition. An advantage of this internal model is that it is zero input globally asymptotically stable. This fact will greatly facilitate the global stabilization of the augmented system associated with the given plant and the internal model. Then we will further utilize this class of internal models to solve the global robust output regulation problem for output feedback systems with a nonlinear Exosystem. Copyright © 2011 John Wiley & Sons, Ltd.
Jian Peng - One of the best experts on this subject based on the ideXlab platform.
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regional ecosystem health response to rural land use change a case study in lijiang city china
Ecological Indicators, 2017Co-Authors: Jian Peng, Tianyi Li, Jiansheng WuAbstract:Abstract Quantitative analysis of the response of ecosystem health to rural land use change is required to comprehend the human-nature coupling mechanism and to explore the process of global environmental change, which can interpret the ecological effects of regional land use and land cover change comprehensively. However, the existing regional ecosystem health assessment largely ignored either the internal connection of ecosystem health to land use patterns or the internal representation of ecosystem services to ecosystem health. Using Lijiang City of China as a study area, the average normalized difference vegetation index (NDVI), landscape metrics, and ecosystem elasticity coefficient based on different land use types were used as quantitative indicators. Then the coefficient of spatial neighboring effect was introduced to characterize the adjacency effect on ecosystem services, and to generate the index of integrated ecosystem health. The results showed the change of land use was close to 30% at county level from 1986 to 2006, and forest land was the primary land use type. With respect to the declining physical health of ecosystems in all the four counties, the integrated health experienced a slight increase in Lijiang County. The vast majority of towns’ ecosystem physical health and integrated health declined, while more than 70% of towns did not change distinctly. Ecosystem physical health had distinct influence on the integrated ecosystem health, and ecosystem vitality was the main factor affecting the condition of physical health. Emphasized in the interconnection of pattern and process, this study provided an ecosystem health approach to assessing the integrated ecological effects of regional land use change.
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linking ecosystem services and landscape patterns to assess urban ecosystem health a case study in shenzhen city china
Landscape and Urban Planning, 2015Co-Authors: Jiansheng Wu, Jian Peng, Huiling Lv, Xiaoxu HuAbstract:Abstract Ecosystem health assessment is always one of the key topics of ecosystem management. However, few studies has focused on assessing ecosystem health of landscapes, which are geo-spatial units composed of different kinds of ecosystem mosaics. Healthy ecosystems should sustainably provide a range of ecosystem services to meet human needs, and such a concept often cannot be expressed using the traditional ecosystem health assessment. Using Shenzhen City in China as a case study area, this research aims to assess the ecosystem health of urban landscapes based on ecosystem services. Results showed a distinct deterioration of urban ecosystem health for all of the 30 units assessed in Shenzhen City during 1978–2005. Five levels were classified with respect to health using fixed thresholds. There were 12 towns appearing with the worst level and 4 towns disappearing with the best level in 2005 compared with the status in 1978. Although there was no significant decrease in the level of health during 1978–2000, by 2005 more than 70% of towns belonged to the top two levels, classifying them as unhealthy. Among all the assessing indicators, the indicators of ecosystem organization contributed least to ecosystem health, except in 1986, and ecosystem services were found to be the most contributive indicator during 1978–2005. It was also suggested that land use patterns provided an integrating bridge among regional ecosystem health, economic development, and environmental performances.
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evaluation for regional ecosystem health methodology and research progress
Acta Ecologica Sinica, 2007Co-Authors: Jian Peng, Yanglin Wang, Jiansheng Wu, Yuqing ZhangAbstract:Abstract The evaluation for ecosystem health is one of the hotspots in the fields of macro-ecology and ecosystem management. Conducting analysis at the regional scale is an important direction for evaluating ecosystem health. Changing the spatial scale from the local to the regional level leads to great differences in targets and methodologies for ecosystem health evaluation and creates a new direction for regional ecosystem health research. Compared with the ecosystem health at the local scale, which refers to a single ecosystem type, the regional ecosystem health focuses on the health conditions and spatial patterns of different ecosystem types. However, there has been little attention paid to this very research up to now. Based on the progress on ecosystem health studies at the regional scale, the study reported in this article aims to discuss the implications of the conception of regional ecosystem health and to put forward a methodology for evaluating the regional ecosystem health. The main results include: (1) there is a significant scaling effect on the ecosystem health analysis, and the regional level is the key scale used to focus on the correlation between spatially neighboring ecosystems in terms of ecosystem health; (2) regional ecosystem health can be defined through 4 aspects, i.e., vigor, organization, resilience, and ecosystem service functions; (3) the basic evaluation objects of the regional ecosystem health is spatial entity, which is the matrix of different ecosystem types; (4) indicator system method is the only approach to evaluate regional ecosystem health; (5) the absolute thresholds of the evaluation indicators for the regional ecosystem health do not exist; the aim of the evaluation is to discuss the temporal dynamic changes and spatial differences of health conditions rather than to ascertain whether a region is healthy or not in view of ecological sustainability; and (6) the integration of evaluation results at multispatial scales, the application of this methodology in the landscape ecology, and the utilization of geographic information systems (GIS), remote sensing (RS), and Global Positioning Systems (GPS) technologies are the main directions for further research.
Jiansheng Wu - One of the best experts on this subject based on the ideXlab platform.
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regional ecosystem health response to rural land use change a case study in lijiang city china
Ecological Indicators, 2017Co-Authors: Jian Peng, Tianyi Li, Jiansheng WuAbstract:Abstract Quantitative analysis of the response of ecosystem health to rural land use change is required to comprehend the human-nature coupling mechanism and to explore the process of global environmental change, which can interpret the ecological effects of regional land use and land cover change comprehensively. However, the existing regional ecosystem health assessment largely ignored either the internal connection of ecosystem health to land use patterns or the internal representation of ecosystem services to ecosystem health. Using Lijiang City of China as a study area, the average normalized difference vegetation index (NDVI), landscape metrics, and ecosystem elasticity coefficient based on different land use types were used as quantitative indicators. Then the coefficient of spatial neighboring effect was introduced to characterize the adjacency effect on ecosystem services, and to generate the index of integrated ecosystem health. The results showed the change of land use was close to 30% at county level from 1986 to 2006, and forest land was the primary land use type. With respect to the declining physical health of ecosystems in all the four counties, the integrated health experienced a slight increase in Lijiang County. The vast majority of towns’ ecosystem physical health and integrated health declined, while more than 70% of towns did not change distinctly. Ecosystem physical health had distinct influence on the integrated ecosystem health, and ecosystem vitality was the main factor affecting the condition of physical health. Emphasized in the interconnection of pattern and process, this study provided an ecosystem health approach to assessing the integrated ecological effects of regional land use change.
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linking ecosystem services and landscape patterns to assess urban ecosystem health a case study in shenzhen city china
Landscape and Urban Planning, 2015Co-Authors: Jiansheng Wu, Jian Peng, Huiling Lv, Xiaoxu HuAbstract:Abstract Ecosystem health assessment is always one of the key topics of ecosystem management. However, few studies has focused on assessing ecosystem health of landscapes, which are geo-spatial units composed of different kinds of ecosystem mosaics. Healthy ecosystems should sustainably provide a range of ecosystem services to meet human needs, and such a concept often cannot be expressed using the traditional ecosystem health assessment. Using Shenzhen City in China as a case study area, this research aims to assess the ecosystem health of urban landscapes based on ecosystem services. Results showed a distinct deterioration of urban ecosystem health for all of the 30 units assessed in Shenzhen City during 1978–2005. Five levels were classified with respect to health using fixed thresholds. There were 12 towns appearing with the worst level and 4 towns disappearing with the best level in 2005 compared with the status in 1978. Although there was no significant decrease in the level of health during 1978–2000, by 2005 more than 70% of towns belonged to the top two levels, classifying them as unhealthy. Among all the assessing indicators, the indicators of ecosystem organization contributed least to ecosystem health, except in 1986, and ecosystem services were found to be the most contributive indicator during 1978–2005. It was also suggested that land use patterns provided an integrating bridge among regional ecosystem health, economic development, and environmental performances.
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evaluation for regional ecosystem health methodology and research progress
Acta Ecologica Sinica, 2007Co-Authors: Jian Peng, Yanglin Wang, Jiansheng Wu, Yuqing ZhangAbstract:Abstract The evaluation for ecosystem health is one of the hotspots in the fields of macro-ecology and ecosystem management. Conducting analysis at the regional scale is an important direction for evaluating ecosystem health. Changing the spatial scale from the local to the regional level leads to great differences in targets and methodologies for ecosystem health evaluation and creates a new direction for regional ecosystem health research. Compared with the ecosystem health at the local scale, which refers to a single ecosystem type, the regional ecosystem health focuses on the health conditions and spatial patterns of different ecosystem types. However, there has been little attention paid to this very research up to now. Based on the progress on ecosystem health studies at the regional scale, the study reported in this article aims to discuss the implications of the conception of regional ecosystem health and to put forward a methodology for evaluating the regional ecosystem health. The main results include: (1) there is a significant scaling effect on the ecosystem health analysis, and the regional level is the key scale used to focus on the correlation between spatially neighboring ecosystems in terms of ecosystem health; (2) regional ecosystem health can be defined through 4 aspects, i.e., vigor, organization, resilience, and ecosystem service functions; (3) the basic evaluation objects of the regional ecosystem health is spatial entity, which is the matrix of different ecosystem types; (4) indicator system method is the only approach to evaluate regional ecosystem health; (5) the absolute thresholds of the evaluation indicators for the regional ecosystem health do not exist; the aim of the evaluation is to discuss the temporal dynamic changes and spatial differences of health conditions rather than to ascertain whether a region is healthy or not in view of ecological sustainability; and (6) the integration of evaluation results at multispatial scales, the application of this methodology in the landscape ecology, and the utilization of geographic information systems (GIS), remote sensing (RS), and Global Positioning Systems (GPS) technologies are the main directions for further research.
Slinger Jansen - One of the best experts on this subject based on the ideXlab platform.
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measuring the health of open source software ecosystems beyond the scope of project health
Information & Software Technology, 2014Co-Authors: Slinger JansenAbstract:Abstract Background The livelihood of an open source ecosystem is important to different ecosystem participants: software developers, end-users, investors, and participants want to know whether their ecosystem is healthy and performing well. Currently, there exists no working operationalization available that can be used to determine the health of open source ecosystems. Health is typically looked at from a project scope, not from an ecosystem scope. Objectives With such an operationalization, stakeholders can make better decisions on whether to invest in an ecosystem: developers can select the healthiest ecosystem to join, keystone organizers can establish which governance techniques are effective, and end-users can select ecosystems that are robust, will live long, and prosper. Method Design research is used to create the health operationalization. The evaluation step is done using four ecosystem health projects from literature. Results The Open Source Ecosystem Health Operationalization is provided, which establishes the health of a complete software ecosystem, using the data from collections of open source projects that belong to the ecosystem. Conclusion The groundwork is done, by providing a summary of research challenges, for more research in ecosystem health. With the operationalization in hand, researchers no longer need to start from scratch when researching open source ecosystems’ health.
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Python: Characteristics identification of a free open source software ecosystem
Digital Ecosystems and Technologies (DEST), 2013 7th IEEE International Conference on, 2013Co-Authors: R. Hoving, G. Slot, Slinger JansenAbstract:Analysing a free open source software ecosystem can be beneficial and can help stakeholders in numerous ways. The analysis can help developers, investors, and contributors, to decide which software ecosystem to invest in and where to invest. Another reason for making an analysis is to assist ecosystem coordinators in governing their ecosystem. The paper provides an insight on the free open source software ecosystem of Python. It presents an analysis of the software ecosystem itself and the different characteristics it has. Based upon the conducted analysis with the available dataset, the research concludes that the free open source software ecosystem of Python contains three ecosystem roles that define its ecosystem. Next to that, it has grown exponentially from 31 active developers in 2005 to 5,212 December 2012. These results can help set up a strategy for the future of the Python ecosystem. At this point in time, it is necessary to make arrangements for the ongoing growth of the Python ecosystem. Failing to do so can lead to a growing number of unusable features, and eventually advance to an unhealthy ecosystem.
Zhiyun Ouyang - One of the best experts on this subject based on the ideXlab platform.
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research progress on the relationship between biodiversity and ecosystem services
Journal of Applied Ecology, 2020Co-Authors: Zhi Wen, Hua Zheng, Zhiyun OuyangAbstract:The relationship between biodiversity and ecosystem services is one of the hot topics in ecological research. The ways that the relationship is applied to the development of ecosystem management and policy have gradually gained attention after the Millennium Ecosystem Services Assessment in 2005. However, applying theoretical understanding of the relationship into practical management still faces challenges. Examining recent progresses may help to guide practices and po-licies. We summarized recent progress in researches on the relationship between biodiversity and ecosystem services in terms of the impacts of biodiversity on single ecosystem service, ecosystem multifunctionality and trade-offs of ecosystem services, as well as how environmental changes affected these relationships. Moreover, we outlined the application of these relationships in nature reserve management, forest management, degraded ecosystem restoration, and agro-ecosystem improvement. We further analyzed the shortcomings in relationship studies and then emphasized that future research and practice trends are the interaction of different biodiversity components and multiple trophic levels on ecosystem services, the coupling effects of environmental changes on the relationships, and practical approaches to biodiversity for improving ecosystem services.
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mapping ecosystem service bundles to detect distinct types of multifunctionality within the diverse landscape of the yangtze river basin china
Sustainability, 2018Co-Authors: Lingqiao Kong, Hua Zheng, Zhiyun Ouyang, Yi Xiao, Jingjing Zhang, Binbin HuangAbstract:The tradeoffs and synergies of ecosystem services are widely discussed and recognized. However, explicit information for understanding and managing the complex relationships of multiple ecosystem services at regional scales is still lacking, which often leads to the degradation of important ecosystem services due to one ecosystem service being enhanced over another. We assessed the biodiversity and the production of nine ESs (ecosystem services) across 779 counties in the Yangtze River Basin, the largest basin in China. Then, we mapped the distribution of ES for each county and used correlations and “partitioning around medoids” clustering analysis to assess the existence of ES bundles. We found five distinct types of bundles of ecosystem services spatially agglomerated in the landscape, which could be mainly explained by land use, slope and altitude gradients. Our results also show landscape-scale tradeoffs between provisioning and almost all regulating services (and biodiversity), and synergies among almost all regulating services (and biodiversity). Mapping ecosystem service bundles can identify areas in a landscape where ecosystem management has produced exceptionally desirable or undesirable sets of ecosystem services, and can also provide explicit, tailored information on landscape planning for ecosystem service conservation and the design of payment policies for ecosystem services within diverse landscapes at watershed scales.
