1,720,975 research outputs found
An experimental study of stratified-dispersed flow in horizontal pipes
No full textThe tracer method has been adopted to study stratified–dispersed flow in a horizontal pipe, 80 mm in diameter and 50 m long, operating at 5 Bar with nitrogen–water mixtures. The use of the tracer method in a horizontal pipe required the development of a specially designed test section, the related electronics and a data acquisition system. It has also been necessary to develop a tracer injection system, which has been designed in order to obtain uniform tracer concentration in the liquid film immediately after its injection. The main flow parameters which can be measured with the present experimental set-up are the circumferential distribution of the film height, flow rate and tracer concentration, the rates of droplet entrainment and deposition and the split of the liquid phase between the wall layer and the entrained droplets. The average tracer concentration data have been interpreted with a new three-field model of the liquid phase in the stratified–dispersed flow pattern. In the present formulation, the model holds for steady, fully developed flow conditions and is based on a one-dimensional description of the flow system. The data cover a limited number of flow conditions
Implementing Tour Guides for Travellers
No full textThe impending "intelligent car" scenario can have a great impact on improving the quality of life of a number of citizens by reducing wasted time and enhancing interaction with the environment. In this article, the authors describe their development of tour guides on palmtop computers that present tourists with high-quality multimedia information and services. An important added value of tour guides on palmtop computers is that they can assist the user in the real-time event (e.g., in a museum or while walking in a city) and during the in-car trip as well. However, the overall surrounding environment and the contextual tasks performed by the user are different. In-car use is challenging because it requires adapting the interaction modes of the user to the strict safety constraints of driving. The authors have explored these issues in the development of a tour guide for the Castellon region of Spain. In this article, they present ideas and discuss preliminary findings on their interface design. © 2005 Wiley Periodicals, Inc
oDect: an RFID-based Object Detection API to support applications development on Mobile Devices
No full textThe RFID technology is becoming ever more popular in the development of ubiquitous computing applications. A full exploitation of the RFID potential requires the study and implementation of human–computer interaction (HCI) modalities to be able to support wide usability by the target audience. This implies the need for programming methodologies specifically dedicated to support the easy and efficient prototyping of applications to have feedback from early tests with users. On the basis of our field-working experience, we have designed oDect, a high-level language and platform-independent application programming interface (API), ad hoc designed to meet the needs of typical applications for mobile devices (smart phones and PDAs). oDect aims at allowing application developers to create their prototypes focusing on the needs of the final users, without having to care about the low-level software that interacts with the RFID hardware. Further, in an end-user developing (EUD) approach, oDect provides specific support for the application end-user herself to cope with typical problems of RFID applications in detecting objects. We describe in detail the features of the API and discuss the findings of a test with four programmers, where we analyse and evaluate the use of the API in four sample applications. We also present results of an end-user test, which investigated strengths and weaknesses of the territorial agenda (TA) concept. The TA is an RFID-based citizen guide that aids—through time- and location-based reminders—users in their daily activities in a city. The TA directly exploits EUD features of oDect, in particular concerning the possibility of linking detected objects with custom actions
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