We have undertaken a research project to design an innovative distributed optimization environment in which modeling languages, servers, registries, communication agents, interfaces, analyzers, solvers, and simulation engines can be implemented as services and utilities under a unified framework. Our work, which we call Optimization Services or OS, defines standards for all activities necessary to support decentralized optimization on the Internet: representation of optimization instances, results, and solver options; communication between clients and solvers; and discovery and registration of optimization-related software using the concept of Web Services. In this paper we place emphasis on issues in distributed computing that are posed by the special character of optimization. We also describe a reference implementation that is freely available as an open-source project of COIN-OR.
Chalcone structures obtained by structural tailoring are an important class of molecular organic nonlinear optics (NLO) crystals that can be used for multiple purposes. In this work, two novel chalcone compound crystals with noncentrosymmetric structures, 6MN3MPP (C 21 H 18 O 3 , Pca2 1 ) and 6MN4MPP (C 21 H 18 O 3 , Pn), were designed and grown by extending the π-conjugation and structure-modifying strategy. On this basis, the second harmonic generation (SHG) efficiency, thermal stability, transmission spectra, dielectric constant, and photoluminescence properties of the crystal were characterized, and the hyperpolarizability of the crystal was theoretically calculated. The results show that the synthesized crystals exhibit higher crystal transparency (≥70%), higher melting point, and lower dielectric constant (ε r ≈ 6.5) compared with other reported chalcone NLO crystals. In particular, the SHG intensity of the 6MN3MPP crystal is 4.3 times higher than that of the KDP crystal. All of the results show that the two newly synthesized compounds have good application prospects as NLO crystals.
Distributed computing technologies such as Web Services are growing rapidly in importance in today's computing environment. In the area of mathematical optimization, it is becoming increasingly common to separate modeling languages from optimization solvers.In fact, the modeling language software, solver software, and data used to generate a model instance might reside on different machines using different operating systems. Such a distributed environment makes it critical to have an open standard for exchanging model instances.In this paper we present OSiL (Optimization Services instance Language), an XMLbased computer language for representing instances of large-scale optimization problems including linear programs, mixed-integer programs, quadratic programs, and very general nonlinear programs. OSiL has two key features that make it much superior to current standard forms for optimization problem instances. First, it uses the object-oriented features of XML schemas to efficiently represent nonlinear expressions. Second, its XML schema maps directly into a corresponding in-memory representation of a problem instance. The inmemory representation provides a robust application program interface for general nonlinear programming, facilitates reading and writing postfix, prefix, and infix formats to and from the nonlinear expression tree, and makes the expression tree readily available for function and derivative evaluations.
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