Selection of Optimal Values in Spatial Estimation of Environmental Variables using Geostatistical Simulation and Loss Functions

Journal of the Korean Earth Science Society, v. 31, no. 5, p. 437−447, September 2010

No-Wook Park

“Spatial estimation of environmental variables has been regarded as an important preliminary procedure for decision-making. A minimum variance criterion, which has often been adopted in traditional kriging algorithms, does not always guarantee the optimal estimates for subsequent decision-making processes. In this paper, a geostatistical framework is illustrated that consists of uncertainty modeling via stochastic simulation and risk modeling based on loss functions for the selection of optimal estimates. Loss functions that quantify the impact of choosing any estimate different from the unknown true value are linked to geostatistical simulation. A hybrid loss function is especially presented to account for the different impact of over- and underestimation of different land-use types. The loss function-specific estimates that minimize the expected loss are chosen as optimal estimates. The applicability of the geostatistical framework is demonstrated and discussed through a case study of copper mapping.”

Designing Integrated High Performance Web Portals for GIScience Research

Journal of Internet Technology, Vol. 11 No. 6, P.809-820 (2010/12)

Tong Zhang, Ming-Hsiang Tsou, Qinghua Qiao, Bin Hu

“Web portals can be used as comprehensive platforms to deliver high-level Internet Geographic Information Services (GIService). Web portals can be enhanced by high performance Geocomputation and emerging Internet technologies to improve performance, interoperability, reliability, usability, and security. The integration of emerging technologies introduces new challenges for designing efficient and flexible high performance GIS web portals. This paper summarizes design principles for the development of high performance web portals to support GIScience research. Following the design principles, a technical implementation plan of a web portal to support GIScience research at a geography department is outlined using state-of-the-art computing technologies, including high performance computing, Web services, Internet GIServices, and web portals. A simple prototype demonstrates the feasibility of the technical plan as well as the effectiveness of the design principles.”