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Polymer dispersed liquid crystal (PDLC) films have potential applications in many aspects due to unique electrically switching properties, and thus the films with excellent comprehensive properties are highly demanded at present. In this study, aromatic polyurethane acrylate (PUA) was used as polymer-matrix, and effect of diluents [lauryl methacrylate (LMA) and isobornyl acrylate (IBOA)] content on the electrical-optical properties of PDLC films was investigated. The results indicate that increase of PUA/LMA or decrease of LMA/IBOA weight ratio increases threshold and saturation voltages (Vth and Vsat), decreases on- and off-state transmittances (Ton and Toff) and increases contrast ratio. Under optimised PUA/LMA weight ratio of 31/19 or PUA/LMA/IBOA weight ratio of 31/15/4, the Vth and Vsat of the films first increase and then decrease with increasing Ag nanowires (NWs) content, and better overall properties are achieved at 0.05 or 0.075 wt.% Ag NWs, respectively. In order to explore essential reasons for the influence of diluents and Ag NWs on the properties of PDLC films, the relationships between film properties (Vth or Vsat, Ton, Toff, and response time) and liquid crystal (LC) droplets size were analysed emphatically, and the changes of system viscosity and anchoring force between polymer-matrix and LC droplets were also discussed.

Under the umbrella of the Western European Armament Group's THALES Memorandum of Under-standing, a "Common Framework for Verification, Validation, and Accreditation of Simulations" (nickname "REVVA") was developed and stabilized during the period March 2003 through October 2004. Within the Joint Program between Denmark, France, Italy, Sweden, and The Netherlands, a VV&A methodology was developed, which includes: (1) The REVVA Generic Process, a stand-alone VV&A process, which can be easily linked to numerous types of model devel-opment processes, including such for the development of distributed simulations (e.g., the FEDEP); (2) The concepts of Target of Acceptance (ToA) and Target of Verification and Validation (ToVV), which put a strong emphasis on V&V requirements definition, formalization of V&V planning, and traceability from the individual Items of Evidence ac-quired during V&V implementation up to the intended purpose of model use; (3) The explicit distinction between the properties "correctness" and "validity", which are inherent to a simulation model and its intended use on the one hand, and the processes of "verification" and "validation" to reveal them on the other hand; (4) Hooks for the integration of methods for estimation of uncertainty introduced because of the current inability to prove neither correctness nor va-lidity; (5) A definition of roles, which clearly distinguishes technical and managerial roles and sides from which the actors may come; (6) A demarcation of "worlds" related to or associated with modeling and simulation; And (7) an extensive review of techniques to support the making of a more objective acceptance decision. The ToA and the ToVV are consistent with the documentation requirements defined in the International Test Operations Procedure on V&V (WGE7.2), and the proposed methodology creates a stable framework for activities such as the NATO MSG019/TG016 "VV&A of HLA Federations". This paper presents the building blocks of the REVVA methodology, and motivates the objectives of the follow-on program.

Within the WEAG THALES Joint Program 11.20 "Common Framework for Verification, Validation, and Accreditation of Simulations" (nicknamed "REVVA") between Denmark, France, Italy, Sweden, and The Nether-lands, a new customer-based and product-oriented VV&A methodology was developed. It includes: (1) The REVVA Generic Process, a stand-alone VV&A process, which can be easily linked to numerous types of model development processes; (2) The concepts of Target of Acceptance (ToA) and Target of Verification and Validation (ToVV), which put a strong emphasis on V&V requirements definition and traceability from the individual Items of Evidence acquired during V&V implementation up to the intended purpose of model use; (3) The explicit distinction between the proper-ties "correctness" and "validity", which are inherent to a simulation model on the one hand, and the processes of "verification" and "validation" to reveal them on the other hand; (4) Hooks for the integration of methods for estimation of uncertainty introduced by the current inability to prove neither correctness nor validity; (5) A role model, which clearly distinguishes technical and managerial roles and parties from which the actors may come. The follow-on project “REVVA2” shall formalize these former results and its own methodological basis. REVVA2 must also show its complementarities with other approaches such as the International Test Operations Procedure on V&V (WGE7.2) and the combined effort on HLA Federation VV&A by the NATO MSG019/TG016 and the SISO VV&A PDG. The ultimate objective of REVVA2 is the production of a set of documents that have to satisfy two kinds of goals: they have to be written in a style suitable for their submission to international standardization organizations, and need to be immediately applicable by VV&A practitioners. This paper, based on the Spring 05 SIW paper 041, outlines the results achieved by the first study and motivates future research and standardization directions.