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We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system's successes and failures and outline our plans for future research and development.

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This paper describes the oxidation behaviour of two technologically important nickel based superalloys, RR3000 and CMSX-4, used extensively in gas turbine blade applications. Oxidation tests were conducted in air at 1100uC for equal and extended periods of time, up to 100 h to compare the superalloys characteristic properties. The morphology of oxide growth in the test samples was investigated using metallography, SEM, EDX, X-ray diffraction (XRD) and Cr 3z photoluminescence spectroscopy. The results indicated that irrespective of the duration of exposure, alloy RR3000 develops a much thicker oxide scale than alloy CMSX-4. Examination of cross-sections revealed that the scale grown on the alloy RR3000 is porous and has a three layered structure consisting of an outer layer of (Ni,Co)O; a sublayer of CrTaO 4 rich oxide with different spinels; and an inner layer of a-Al 2 O 3 . By contrast, the scale that forms on alloy CMSX-4 is compact and consists of two layers. The upper layer is primarily composed of spinels (Ni,Co)Al 2 O 4 and (Ni,Cr) 2 O 4 , and the inner layer of a-Al 2 O 3 . Residual stress measurements using luminescence spectroscopy point to a weak adhesion of the oxide scale to the substrate for alloy RR3000 and a strong adhesion for alloy CMSX-4.

Independent shopping in modern grocery stores that carry thousands of products is a great challenge for people with visual impairments. ShopTalk is a proof-of-concept wearable system designed to assist visually impaired shoppers with finding shelved products in grocery stores. Using synthetic verbal route directions and descriptions of the store layout, ShopTalk leverages the everyday orientation and mobility skills of independent visually impaired travelers to direct them to aisles with target products. Inside aisles, an off-the-shelf barcode scanner is used in conjunction with a software data structure, called a barcode connectivity matrix, to locate target product on shelves. Two experiments were performed at a real world supermarket. A successful earlier single-subject experiment is summarized and a new experiment involving ten visually impaired participants is presented. In both experiments, ShopTalk was successfully used to guide visually impaired shoppers to multiple products located in aisles on shelves. ShopTalk is a feasible system for guiding visually impaired shoppers who are skilled, independent travelers. Its design does not require any hardware instrumentation of the store and leads to low installation and maintenance costs.

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