The System for Population Kinetics (SPK)
David Salinger and the Resource Facility for Population Kinetics (RFPK)
Dept. of Bioengineering, University of Washington
The System for Population Kinetics (SPK) is a data analysis software designed to assist in the development and identification of nonlinear mixed effects models in a variety of experimental situations. SPK is currently deployed as a web service, but will also be released under an open source license. For parameter estimation, the service provides access (at present) to approximations of the likelihood function based on linearization of the kinetic model at suitable individual estimates, as well as two-stage methods, a nonparametric method and Monte Carlo likelihood integration at the optimal parameter estimate (an approach to post-optimality testing). SPK is developed under a three-tiered architecture that includes a client tier (which runs on the user's desktop) and a computational tier (which runs on external servers). The client application is the Model Design Agent (MDA), a Java program which assembles user inputs and displays the required graphical or numerical outputs, and coordinates communication between the user and the computational tier. Structural models, either algebraic or systems of ODEs, are defined by the user via a NONMEM-compatible language, available both through a text-based input wizard and a graphical model-building tool. A searchable database provides access to past analyses in an XML format parsed by the MDA. The SPK service is under development and as of now is available on a trial basis via http://spk.rfpk.washington.edu/.
The Resource Facility for Population Kinetics (RFPK, http://www.rfpk.washington.edu/) at the University of Washington is a research resource funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) at the National Institutes of Health. The mission of the RFPK is to encourage and support research and development in modeling and simulation of biological systems and their application in a variety of areas, at the same time deploying novel software tools that implement useful methodological advances. The development of SPK is partially supported by grant NIH P41 EB001975.