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Earth science relies on software to prepare, distribute, access, manipulate and analyze data. Scientific replication often requires reuse of the original software. Similarly, efficiently distributing, accessing or analyzing scientific data often requires software reuse. Recognizing the value of software reuse, the Earth science software community has encouraged and fostered reuse within the community. The NASA Earth Science Data Systems (ESDS) Software Reuse Working Group (WG) was established to support software reuse among members of the community. The WG developed the software reuse portal to inform the community about reuse issues and available resources and educate the community on improving software reuse practices. Requirements for a Reuse Enablement System (RES) have been developed and are being used to implement a prototype system to provide access to software for potential reuse. Reuse Readiness Levels are being developed to document criteria and improve capabilities for evaluating and selecting software for potential reuse.

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The reuse of software and related artifacts offers the potential for cost savings in various industries and has contributed to the development of the cyberinfrastructure that is used by the Earth science community. Developing measures that enable the assessment of software in terms of its potential reusability can contribute to efforts of both developers and reusers of software. Draft Reuse Readiness Levels (RRLs) have been developed as an instrument for assessing the maturity of software products for potential reuse. The process employed to develop the draft RRLs is described, and the initial summary of topic areas defined for each level is presented. Based on recommendations from the community of Earth science data systems software developers, areas for improving the precision of the draft RRLs have been identified and an approach for identifying enhancements is described.

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An important part of promoting software reuse is to ensure that reusable software assets are readily available to the software developers who want to use them. Through dialogs with the community, the NASA Earth Science Data Systems Software Reuse Working Group has learned that the lack of a centralized, domain- specific software repository or catalog system addressing the needs of the Earth science community is a major barrier to software reuse within the community. The Working Group has proposed the creation of such a reuse enablement system, which would provide capabilities for contributing and obtaining reusable software, to remove this barrier. The Working Group has recommended the development of a Reuse Enablement System to NASA and has performed a trade study to review systems with similar capabilities and to identify potential platforms for the proposed system. This was followed by an architecture study to determine an expeditious and cost-effective solution for this system.

A number of software packages and systems were examined through both creating prototypes and examining existing systems that use the same software packages and systems. Based on the results of the architecture study, the Working Group developed a prototype of the proposed system using the recommended software package, through an iterative process of identifying needed capabilities and improving the system to provide those capabilities. Policies for the operation and maintenance of the system are being established for the system, and the identification of system policies also has contributed to the development process. Additionally, a test plan is being developed for formal testing of the prototype, to ensure that it meets all of the requirements previously developed by the Working Group. This poster summarizes the results of our work to date, focusing on the most recent activities.

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The NPOESS Preparatory Project (NPP) provides remotely-sensed land, ocean, atmospheric, ozone, and sounder data that will serve the meteorological and global climate change scientific communities while also providing risk reduction for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), the U.S. Government's future low-Earth orbiting satellite system monitoring global weather and environmental conditions. NPOESS is a joint mission of three federal agencies, NASA, NOAA, and DoD. NASA Science Data Segment's (SDS) primary role in NPP is to independently assess the quality of the NPP science and environmental data records for climate research. Such assessment is critical for making NPOESS products the best that they can be for operational use and ultimately for climate studies. The SDS supports science assessment by assuring the timely provision of NPP data to NASA's science teams organized by climate measurement themes. The SDS breaks down into nine major elements, an input element that receives data from the operational agencies and acts as a buffer, a calibration analysis element, five elements devoted to measurement based quality assessment, an element used to test algorithmic improvements, and an element that provides overall science direction. This paper describes how the NPP SDS leveraged existing systems, the final systems architectures and lessons learned for the development of mission-reliable research ready systems capable of supporting the assessment of NPP derived measurements.

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Over the years, numerous large and complex information systems have been created to store, process, and disseminate vast volumes of remotely-sensed Earth science data. These systems have the potential to be reused to process similar data from other missions or instruments, reducing risk, schedule, and associated development cost for future projects.

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Packaging software assets for reuse can improve the potential for others to adopt the software. Packaging the software with appropriate documentation and other resources can facilitate decision-making by those considering adoption and can enable them to implement the software more efficiently. Software that can be easily integrated is more likely to be shared with others and reused by the recipients. The NASA Earth Science Data Systems (ESDS) Software Reuse Working Group has been chartered to oversee the process that will maximize the reuse of potential software components. As part of this work, a portal Web site was created to support reuse practices within the Earth science community. This portal also serves as an example of reuse practices, both as a recipient and as a contributor to reuse. This paper describes the assets that were reused to develop the software reuse portal. For each asset reused, we identify the type, format, and licensing restrictions. This case study exemplifies reuse at various scopes such as the application, component, and function level. Aside from consuming reusable assets, the software produced was also made available for reuse. We address proper packaging methodologies to foster easy integration and reuse. We obtain various reuse metrics based on an analysis of the final system and the impact in our community. We identify caveats in current metrics such as consideration for emerging technologies and intangible benefits.

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NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) land product validation project, initiated prior to the launch of the NASA Earth Observing System (EOS) Terra platform in late 1999, provides data, instrument, and information resources for the validation of products that quantify land surface characteristics from MODIS and other satellite sensors. Land products derived from MODIS and other moderate-resolution sensors include, among others, land cover, snow cover extent, surface temperature, leaf area index, fire occurrence, and vegetation productivity.

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When software is developed with reuse purposes in mind from the start, the resulting product will often be more mature, in a reuse sense, than products which are modified for reuse purposes after they have been developed. But it can be difficult to assess the maturity level of a software product due to the variety of factors that influence its reusability. If these factors could be measured, assessed, and combined into a single scale measuring the maturity of the software in terms of reusability, it would be of great benefit to developers. They will more easily be able to determine how ready the software is for their purposes, and how much modification may be necessary before it can fill their needs. The NASA Earth Science Data Systems (ESDS) Software Reuse Working Group is in the process of developing a set of Reuse Readiness Levels (RRLs) for the purpose of determining the reuse maturity of software assets. These levels are modeled after NASA's Technology Readiness Levels (TRLs), which have been used for many years, particularly for assessing hardware's readiness for spaceflight purposes. To assess the reuse maturity of software, a number of factors are included in the Working Group's development of the RRL scale including portability, extensibility, documentation, support, packaging, intellectual property and licensing issues, standards compliance, verification and testing, and modularity. Members of the working group have described the levels reusable software goes through as it becomes more mature in each of these areas. These individual levels will be combined into a single RRL scale that will allow a single number to describe the reuse maturity of software. This presentation will describe the Working Group's efforts in the creation of the Reuse Readiness Level (RRL) scale.

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Software reuse provides many benefits, most notably saving time, saving money, and ensuring reliability. The Earth science community can benefit by sharing software assets such as code, applications, documentation, and standards. However, there are also challenges involved in reusing software, and these barriers must be identified and broken down in order to encourage more systematic software reuse. The NASA Earth Science Data Systems (ESDS) Software Reuse Working Group has been chartered to oversee the process that will maximize the reuse of potential software components. As part of this work, we have collected case studies from members of the ESDS Software Reuse Working Group about their experiences in software reuse. This poster will present information from four such case studies, including a comparison of the common issues they faced and how those issues were resolved. The presentation will examine some of the lessons learned by these projects, how they can be used to improve future software reuse efforts, and include a summary of the benefits realized by these projects.

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This poster provides an overview of the computer system that provides community access to atmospheric measurements derived from backscatter ultraviolet sources. It is funded by NASA's Advancing Collaborative Connections for Earth-Sun System Science (ACCESS), and is devoted to Measurements of Atmospheric Composition in the Ultraviolet. The purpose is to provide "one-stop shopping" for data and information of interested to the Backscattered Ultraviolet (BUV) community. It is built from the well-used, highly successful Total Ozone Mapping Spectrometer (TOMS) web site, and is being evolved into a broader focus for the BUV community. This effort supports NASA's evolutionary step toward science measurement processing and analysis systems, and enables the BUV community to easily access information and expertise from multiple sources over a nearly 30 year history of space-based remote sensing of the atmosphere. It facilitates finding algorithms and scientific results from different parts of the BUV science community as well as from different instruments and missions. It provides the means to access the products of the Ozone Community Oriented Measurement-based Processing System (ComPS). The system contains components that store and manage data, manage user access to that data, provide multi-dimensional views of the data and other information, serve data based on user criteria, and facilitate on-line collaboration. The web site hosts Algorithm Theoretical Basis documents, quality assessment of data products, published papers, instrument descriptions, access to mission information, reports and assessments of events and issues, problem reporting and tracking, a moderated forum, and a user collaboration area. Visitors to the web site fall into several categories: the general public; students, educators, and researchers outside the BUV community; members of the BUV community who validate the measurements; members of the community who develop algorithms and software.

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