Knowledge organisation in a Web‐based environment
Reviews the approaches to the organisation of knowledge in Web‐based environments. The control and structure helps searchers to locate information and services, but only provided that searchers understand and relate to the terms and information structure designed into the system. The other alternative is for the searcher to specify the topic of their search through the use of keywords. These keywords are in the natural language of the searcher, which may or not be coincident with the natural language of the Web sites being searched by the search engine. In order to negotiate the variability of natural language the searcher needs to learn to use more advanced search features such as Boolean searching, nesting and truncation. The knowledge organisation issues associated with access to and retrieval from large databases, such as those that are searched across the Web, are significant and need careful and specialist attention.
08- Hazilah Mohd Amin
This article is aimed at identifying the structure of conventional library classification schemes i.e. the enumerative, hierarchy and faceted structures that can be used to classify web resources. Literature review and case study have been conducted on two organisations, Yahoo! and Staples. The case study explores the hierarchy structure approach used by Yahoo! web directory as well as the faceted structure approach used by Staples, an online retailer. The study revealed that Yahoo! has adopted some of the principles in the conventional library classification scheme. The simple hierarchy structure, as employed by Yahoo, has been utilised by most of the web classifiers due to its ability to classify collections, as well as due to its ability to ease users in selecting the category and drilling down the hierarchy. The faceted structure meanwhile is used by a number of e-commerce websites such as Staples not only because the structure is flexible and able to classify 08Hazilah Mohd Amin 4/26/05, 8:57 AM 133 134 collections, but also because it enables information to be retrieved using category as well as enables multidimensional retrieval. Its application in classifying web resources however, is still at a preliminary stage.
Space Qualification Testing of a Shape Memory Alloy Deployable CubeSat Antenna
Abstract : Increasingly capable CubeSat missions require antenna with improved Radio Frequency performance over the traditional CubeSat antennas. Deployable quadrifilar helical antennas (QHA) enable an acceptable stowing volume and deploy to provide increased gain and bandwidth over traditional patch and dipole antennas. Extensive ground testing is required to ensure the antenna is space qualified and to characterize the antenna deployment in the space environment. AFIT requires a QHA to perform a future CubeSat geolocation mission and contracted Helical Communication Technologies (HCT) to design and manufacture a Shape Memory Alloy (SMA) L-band deployable QHA. Vibration, thermal vacuum, laser vibrometer, and Voltage Standing Wave Ratio (VSWR) experiments were conducted on the HCT antenna to verify the hardware in a simulated launch environment and to characterize the SMA deployment in the simulated space environment.The HCT QHA successfully passed all required NASA General Environmental Verification Standards space qualification testing. Several anomalies experienced by the QHA encourage a redesign. The deployed antenna length varied from 250-290 mm and future RF testing is required to determine if the antenna geometry variations are significant enough to impact the geolocation mission.This research documents the test results for a QHA deployable CubeSat antenna testing and aids the development of CONOPS for the future AFIT CubeSat mission utilizing the HCT QHAs.