Hierarchical patch dynamics

It parses the dynamics of an action into different layers and encodes such multi-layer temporal information into a joint representation for action recognition. At the first layer, the action sequence is parsed in an unsupervised manner into several smooth-changing stages corresponding to different key poses or temporal structures by temporal clustering. The dynamics within each stage are encoded by mean-pooling or rank-pooling. At the second layer, the temporal information of the ordered dynamics extracted from the previous layer is encoded again by rank-pooling to form the overall representation.

Extensive experiments on a gesture action data set Chalearn Gesture and three generic action data sets Olympic Sports, Hollywood2, and UCF have demonstrated the effectiveness of the proposed method. Check if you have access through your login credentials or your institution to get full access on this article. Authors: Bing Su. Online: 15 September Publication History. This alert has been successfully added and will be sent to: You will be notified whenever a record that you have chosen has been cited.

To manage your alert preferences, click on the button below. Manage my Alerts. New Citation Alert! Save to Binder. Create a New Binder Name. Although the landscape-level metrics were able to characterize the center of urbanization as having the smallest mean patch size and the highest patch richness, patch density, patch size coefficient of variation, landscape shape index, and area-weighted mean shape index, the class-level indices provided more detailed information on the relative contributions of individual land use types.

The high degrees of fragmentation and spatial complexity of the urbanization center were able to be quantified in relation to distance and individual land use types. Processes and factors responsible for urbanization, such as socioeconomic activities and land ownership, resulted in the heterogeneous arrangement of land uses in the Phoenix metropolitan area.

Urban Growth Modeling. We developed computer models to simulate the land use and land cover change in the Phoenix metropolitan region. These models were used to examine a series of model calibration and evaluation methods, and to carry out scenario-based simulation analyses of the future development patterns of the region. The results showed that at finer levels, the noise and uncertainty in input data and the exponentially increased computational requirements would reduce considerably the usefulness and accuracy of such models.

At the other extreme, model projections with too coarse a spatial resolution would be of little use at the local and regional scales. A series of scenario analyses suggested that the Metropolitan Phoenix area would soon be densely populated demographically and highly fragmented ecologically unless dramatic actions are taken soon to slow down the population growth significantly. Also, t here would be an urban morphological threshold over which drastic changes in certain aspects of landscape pattern occur.

Specifically, the scenarios indicated that as large patches of open lands including protected lands, parks, and available desert lands begin to break up, patch diversity would decline partly due to the loss of agricultural lands, and the overall landscape shape complexity also would decrease because of the predominance of urban lands. It seemed that reaching such a threshold could be delayed, but not avoided, if the population in the Phoenix metropolitan region continues to grow.

Effects of Urbanization on Ecosystem Processes. We investigated the effects of three environmental factors associated with urbanization increased air temperature, elevated CO 2 , and N deposition on the ecosystem processes in the Phoenix metropolitan region through ecosystem modeling. Model predictions were validated using field observations. Among other findings, we found that the above-ground net primary productivity ANPP of the Sonoran Desert ecosystem showed positive responses to increases in CO 2 , N deposition, and the combinations of the three environmental factors see Figure 3.

The temperature effect on ANPP was negative when temperature change was larger than 2. ANPP was more sensitive to changes in maximum air temperature than in minimum air temperature. The combined effects of the three environmental factors were generally larger than single-factor effects, especially when precipitation was favorable.

With an increase of 24 kg ha -1 y -1 in N deposition rate the maximum value of N deposition increase in the Phoenix urban area , the average ANPP increased by Changes in temperature showed a relatively smaller influence on ecosystem ANPP, with the largest increase in air temperature 3.

Figure 3. Graphs a-c share the same legend as is listed in a. Modeling urban landscape dynamics: a review. Ecological Research ;19 1 A new urban ecology: modeling human communities as integral parts of ecosystems poses special problems for the development and testing of ecological theory.

American Scientist ;88 5 The ecology of urban landscapes: modeling housing starts as a density-dependent colonization process.

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Soil Science Society of America Journal ;66 6 On species occupancy-abundance models. Ecoscience ;9 1 Landscape Ecology ;16 7 Interaction of ecosystem processes with spatial heterogeneity: the puzzle of nitrogen limitation. Oikos ; 2 Use and misuse of landscape indices.

Landscape Ecology ;19 4 The urban funnel model and the spatially heterogeneous ecological footprint. Ecosystems ;4 8 A gradient analysis of urban landscape pattern: a case study from the Phoenix metropolitan region, Arizona, USA. Landscape Ecology ;17 4 Collaborative landscape-scale ecological research: emerging trends in urban and regional ecology. Urban Ecosystems ;7 3 Temperature sensitivity of soil respiration and its effects on ecosystem carbon budget: nonlinearity begets surprises.

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From balance of nature to hierarchical patch dynamics: A paradigm shift in ecology. Overview Fingerprint. Abstract A common assumption historically in ecology is evident in the term "balance of nature. Access to Document Link to publication in Scopus. Fingerprint Dive into the research topics of 'From balance of nature to hierarchical patch dynamics: A paradigm shift in ecology'.

Together they form a unique fingerprint. View full fingerprint. Quarterly Review of Biology , 70 4 , In: Quarterly Review of Biology , Vol.