A framework on task configuration and execution for distributed geographical simulation

Geographical simulation is a popular method in geographical and environmental research.Many models developed to address geographic and environmental issues are distributed worldwide.However,due to the lack of portals,these models are still difficult to invoke for geographical simulations in open web environments.This study designs and develops a framework to assemble service-oriented models from volunteers distributed worldwide for geographical simulations on the web.The framework consists of three layers(task layer,data exchange layer,and model execution layer)that establish a network of serviceoriented locally shared models and simulation tasks for user configurations.With the help of such a framework,users can configure simulation tasks and invoke suitable models shared worldwide for geographical simulations.This article provides an application of the distributed simulation of gross primary production(GPP)by the Biome-BioGeochemical Cycles(BGC)model in China.This application shows that the framework can be beneficial for model assembly from volunteers’computers and distributed simulation tasks that are run for geographical and environmental issues,which can be applied to Digital Earth initiatives.

Geographic modeling and simulation systems for geographic research in the new era: Some thoughts on their development and construction

Regionality,comprehensiveness,and complexity are regarded as the basic characteristics of geography.The exploration of their core connotations is an essential way to achieve breakthroughs in geography in the new era.This paper focuses on the important method in geographic research:Geographic modeling and simulation.First,we clarify the research requirements of the said three characteristics of geography and its potential to address geo-problems in the new era.Then,the supporting capabilities of the existing geographic modeling and simulation systems for geographic research are summarized from three perspectives:Model resources,modeling processes,and operational architecture.Finally,we discern avenues for future research of geographic modeling and simulation systems for the study of regional,comprehensive and complex characteristics of geography.Based on these analyses,we propose implementation architecture of geographic modeling and simulation systems and discuss the module composition and functional realization,which could provide theoretical and technical support for geographic modeling and simulation systems to better serve the development of geography in the new era.

Grid systems for geographic modelling and simulation:A review

Geography requires a comprehensive understanding of both natural and human factors,as well as their interactions.Due to the complexity and multiplicity of geographic problems,various theories and methods for geographic modelling and simulation have been proposed.Currently,geography has entered an era in which quantitative analysis and modelling are essential for understanding the mechanisms of geographic processes.As the basic idea of quantitative spatial analysis,the specified space often needs to be partitioned by a series of small computational units(cells),i.e.,grids.Thus,there is a close relationship between the grids and geographic modelling.This article reviews the mainstream and typical grids used for modelling and simulation.In addition to classification,the derived theories and technologies,including grid generation methods,data organization strategies,multi-dimensional querying methods,and grid adaptation techniques,are discussed.For integrated geographic simulation to explore comprehensive geographic problems,we argued that it is reasonable to build bridges among different types of grids(e.g.,transformation strategies),and more powerful grids that can support multi-type of numerical computation are urgently needed.

A new academic impact metric for evaluating geographic simulation models

Geographic simulation models can be used to explore and better understand the geographical environment. Recent advances in geographic and socio-environmental research have led to a dramatic increase in the number of models used for this purpose. Some model repositories provide opportunities for users to explore and apply models,but few provide a general evaluation method for assessing the applicability and recognition of models. In this study,an academic impact evaluation method for models is proposed. Five indices are designed based on their pertinence. The analytical hierarchy process is used to calculate the index weights,and the academic impacts of models are quantified with the weighted sum method. The time range is controlled to evaluate the life-term and annual academic impacts of the models. Some models that met the evaluation criteria from different domains are then evaluated. The results show that the academic impact of a model can be quantified with the proposed method,and the major research areas that models impact are identified.

Versioned geoscientific workflow for the collaborative geosimulation of human-nature interactions-a case study of global change and human activities

Global change refers to changes in the relationship between humans and nature.It is desirable to actively integrate human social activities into the unified framework of global change so that their mutual relations and functional mechanisms can be understood.This complicated issue necessitates an appropriate method allowing domain experts to collaboratively contribute their knowledge to geoscientific research.Also,an efficient approach to optimize experimentation is of great importance.The reproducibility of research methods and results needs to be improved to boost the sharing of geographic knowledge and resources.This paper proposes a versioned geoscientific workflow and characterizes its full lifecycle using Virtual Geographic Environments,intending to facilitate and improve research related to the interactions between global change and human activities.The geoscientific workflow management is realized using the concept of version management,making geographic simulation methods and computational results easily reproducible and extendable.The sharing and reuse of geographic knowledge in various forms are archived through version management of geoscientific workflows.A versatile prototype system is implemented which enables the visual modeling of geoscientific workflows,the interactive optimization and collaborative evaluation of geoscientific workflows at runtime,the multi-dimensional dynamic visualization of geo-workflow outputs,and role-based access control for data security.