Wiki-Based Stakeholder Participation in Requirements Engineering

Requirements elicitation and documentation are complex activities. So, not only the requirements themselves but also the people involved and the means for managing the requirements will evolve during the project. For example, it might be necessary to add RE personnel, to document templates, or to change the requirements classification scheme. In summary, especially in participative RE, the underlying platform as well the RE approach must be flexible. As the well-known Wikipedia shows, wikis provide a flexible platform for asynchronous collaboration to create content in general. In this article, we investigate how to adapt this approach to support active stakeholder participation in RE. We include a document structure for wiki-based RE and discuss potential problems and solutions based on our experience     

Formability and strength of friction-stir-welded aluminum sheets

Friction stir welding was investigated as a viable process for joining thin aluminum sheets in order to manufacture tailored blanks. In the present study three alloys were tested: 5182-O, 5754-O, and 6022-T4. All three of these alloys are being used to fabricate stamped automotive parts. The gas tungsten arc welding process has been used to make aluminum-tailored welded blanks industrially, so results using this process were compared to FSW results. Blanks of the same gage of all three alloys were welded and then evaluated using tensile and formability testing. The 5xxx series alloys had similar tensile ductility and formability regardless of the welding process. However, the 6022-T4 sheets joined using friction stir welding had better formability than those joined using gas tungsten arc welding because friction stir welding caused less softening in the heat-affected zone.     

Organizational Memory

Ohne Zusammenfassung Eingegangen am 29.06.1998     

Ground Communications Networks for Aeronautical Operations

Three digital communications networks of the FAA performing essential services in support of the National Air Space System (NAS) are described and discussed. Designated as the Aeronautical Fixed Telecommunications Network (AFTN), the combined Weather Teletypewriter Networks A, C, and O, and the Service B Teletypewriter Network, respectively, these systems carry national and international digital message traffic in support of air traffic control operations and aeronautical weather services. These data are exchanged among the Air Traffic Control Centers, Airport Terminal Facilities, and Flight Service Stations of the FAA and in the case of weather data, with offices of the National Weather Service Military Weather and Flight Operations Offices, airlines, and other commercial and industrial interests. Recent and planned modernization programs resulting in the introduction of major computerized electronic message switching centers are also discussed. The electronic data processor configurations, their modes of operation, and specialized data handling features are described. Planned transition and progress to date in converting from 100 word/min teletypewriter operation to medium speed 1200-2400 Bd data rates and from manual inputs to the increasing use of computergenerated messages and computer-to-computer data exchanges are indicated. With the introduction of computerized switching and control centers the overall integration of FAA communications networks into a more fully unified total communications system with more standardized procedures and formats becomes more practical and achievable. Basic concepts and progress towards this goal are outlined.     

Buchbesprechungen

Ohne Zusammenfassung     

Stress-induced light guiding in embossed waveguides

The observation of light guiding in the vicinity of unfilled embossed grooves is reported. Experimental evidence suggests that the guiding is due to residual stresses in the poly (methyl methacrylate) substrate. Preliminary measurements indicate that this guiding phenomenon offers a simple technique for fabricating low-loss-channel optical waveguides.     

In-gel digestion of proteins using a solid-phase extraction microplate

We present a new procedure for in-gel digestion of proteins introducing a combination of two different 96-well microplates. The two plates have incorporated small capillaries with a length of 2.4 mm in each well, one of which has 75-microm-inner diameter capillaries, whereas the second plate has reversed-phase-type capillaries fixed to it. The initial steps of the in-gel digestion process, comprising destaining, reduction/alkylation, dehydration, and digestion, was carried out in the plate containing 75-microm capillaries. Capillaries containing C18 reversed-phase modified monolithic silica rods of a 200-microm diameter were used for the second plate in which extraction and cleanup of peptides were carried out. Peptides were eluted directly from the solid-phase extraction plate onto the MALDI sample support. The separation of the process into two plates led to increased process stability, without compromising sensitivity, i.e. peptide recovery, making it suitable for true high-throughput protein identification. The handling of proteinases could easily be optimized, and no restrictions were made on chosen pH range through the absence of the solid phase in the initial steps of the protocol. Efficient binding of peptides to the solid phase and subsequent direct elution onto the MALDI sample support led to sensitivities in the attomole range. Performance of the process was demonstrated with tryptic digests of proteins stained with colloidal coomassie blue, silver, and the fluorescent stain SYPRO Ruby.