The two most commonly used techniques for evaluating the fit between application design and use - namely, usability testing and beta testing with user feedback - suffer from a number of limitations that restrict evaluation scale (in the case of usability tests) and data quality (in the case of beta tests). They also fail to provide developers with an adequate basis for: (1) assessing the impact of suspected problems (and proposed solutions) on users at large, and (2) deciding where to focus scarce development and evaluation resources to maximize the benefit for users at large. This article describes an approach to usage data and user feedback collection that addresses these limitations to provide developers with a complementary source of usage - and usability-related information. This research has been subjected to a number of evaluative activities including: (1) the development of three research prototypes at NYNEX Corporation, the University of Colorado, and the University of California, (2) the incorporation of one prototype by independent third party developers as part of an integrated demonstration scenario performed by Lockheed Martin Corporation, abd (3) observation and participation in two industrial development projects, at NYNEX and Microsoft Corporations, in which developers sought to improve the application development process based on usage data and user feedback. The proposed approach involves a devlopment platform for creating software agents that are deployed over the Internet to observe application use and report usage data and user feedback to developers to help improve the fit between design and use. The data can be used to illuminate how applications are used, to uncover mismatches in actual versus expected use, and to increase user involvement in the evolution of interactive systems. This research is aimed at helping developers make more informed design, impact assessment, and effort allocation decisions, ultimately leading to more cost-effective development of software that is better suited to user needs.

At ambient conditions, water sits close to phase coexistence with its crystal. More so than in many other materials, this fact is manifested in the fluctuations that maintain a large degree of local order in the liquid. These fluctuations and how they result in long-ranged order, or its absence, are emergent features of many interacting molecules. Their study therefore requires using the tools of statistical mechanics for their their systematic understanding. In this dissertation we develop such an understanding. In particular, we focus on collective behavior that emerges in liquid and solid water. At room temperatures, the thermophysical properties of water are quantified and rationalized with simple molecular models. A key feature of these models is the correct characterization of the competition between entropic forces of packing and the energetic preference for tetrahedral order. At cold temperatures, the properties of ice surfaces are studied with statistical field theory. The theory we develop for the long wavelength features of ice interfaces allows us to explain the existence of a premelting layer on the surface of ice and the stability of ice in confinement. In between these extremes, the dynamics of supercooled water are considered. A detailed theory for the early stages of coarsening is developed and used to explain the peculiar observation of a transient second liquid state of water. When coarsening dynamics are arrested, the result is the formation of a glassy states of water. We show that out-of-equilibrium the phase diagram for supercooled water exhibits a rich amount of structure, including a triple point between two glass phases of water and the liquid. At the end, we explore possible technological implications for the interplay between ordering and frustration in studies of water at metal interfaces.