614 research outputs found

    Simulation of undular bores evolution with damping

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    Propagation of undular bores with damping is considered in the framework of perturbed extended Korteweg-de Vries (peKdV) equation. Two types of damping terms for the peKdV equation, namely linear and Chezy frictional terms, which describe the turbulent boundary layers in the ïŹ‚uid ïŹ‚ow are considered. Solving the peKdV equation numerically using the method of lines shows that under the inïŹ‚uence of damping, the lead-ing solitary wave of the undular bores will split from the nonlinear wavetrain, propagates and behaves like an isolated solitary wave. The amplitude of the leading wave will remain the same for some times before it starts to decay again at a larger time. In general the amplitude of the leading wave and the mean level across the undular bore decreases due to the eïŹ€ect of damping

    Communication Subsystems for Emerging Wireless Technologies

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    The paper describes a multi-disciplinary design of modern communication systems. The design starts with the analysis of a system in order to define requirements on its individual components. The design exploits proper models of communication channels to adapt the systems to expected transmission conditions. Input filtering of signals both in the frequency domain and in the spatial domain is ensured by a properly designed antenna. Further signal processing (amplification and further filtering) is done by electronics circuits. Finally, signal processing techniques are applied to yield information about current properties of frequency spectrum and to distribute the transmission over free subcarrier channels

    The Effect of Fabrication Method on Passive UHF RFID Tag Performance

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    In passive Radio Frequency Identification (RFID), transponders or tags are used to label objects to be identified. In this study passive tag antennas were produced using etching, screen-printing, and gravure printing methods. The threshold and backscattered signal strengths of the tags were measured to determine the effect of different manufacturing methods on the tags' performance. Conductivity, skin depth, thickness, and the quality of the conducting layer have a major effect on tag performance. Each manufacturing method sets its own boundary conditions on the processibility of the high quality conduction layer and such conditions need to be considered in tag design. Tag design also affects the manufacturing parameters used in the different techniques. The results of the study show that each of the studied fabrication methods can be used to manufacture reliable RFID tags

    Strength, water absorption and thermal comfort of mortar bricks containing crushed ceramic waste

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    This present study investigated the crushed ceramic waste utilisation as sand replacement in solid mortar bricks. The percentage of crushed ceramic waste used were 0% (CW0), 10% (CW10), 20% (CW20) and 30% (CW30) from the total weight of sand. The dimension prescribed of mortar bricks are 215 mm x 102.5 mm x 65 mm as followed accordance to MS 2281:2010 and BS EN 771-1:2011+A1:2015. Four (4) tests were conducted on mortar bricks namely crushing strength, water absorption, compressive strength of masonry units and thermal comfort. The incorporation of ceramic waste in all designated mortar bricks showed the increment of crushing strength between 23% and 46% at 28 days of curing and decrement water absorption between 34% and 44% was recorded corresponding to control mortar bricks. The prism test of masonry units consists of mortar bricks containing ceramic waste indicated the high increment of compressive strength at about 200% as compared to mortar brick without ceramic waste. The thermal comfort test of ceramic mortar bricks were also showed the good insulation with low interior temperature. Therefore, the ceramic waste can be utilised as a material replacement to fine aggregate in mortar brick productions due to significant outcomes performed

    The economic viability of radio frequency identification for lumber retailers

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    The purpose of this project is to define the importance of radio frequency identification (RFID) for major lumber retailers. This project will emphasize the cost savings and efficiencies that would be gained by transitioning out of the current bar coded method of tracking into more effective RFID technology. The focus will be to analyze the processes associated with selling lumber and wood-related products with emphasis on inventory visibility of product in retail stores and retail lumber yards. This document will show the realized losses by large lumber retailers from traditional bar coding systems versus their potential return on investment from RFID technology. Each necessary process to sell lumber in the retail environment, from receiving product to the point of sale procedure, will be scrutinized to show the optimal potential results with RFID. The results will be divided into three key areas of savings with RFID: the decrease in labour the higher inventory visibility within the retail location and the reduction in inventory shrinkage. Speculative examples will also be discussed to give better understanding of the retail processes and their prospective economic benefits. This project has been devised to help lumber retailers realize the potential of the technology and direct them to pull the demand of implementation from their suppliers and throughout their own supply chains. --P. ii.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b173796

    Strategic Niche Management (SNM) beyond sustainability. An exploration of key findings of SNM through the lens of ICT and privacy

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    Recently the governance of socio-technical transitions to sustainability is gaining attention in the field of innovation studies. One particular approach is that of Strategic Niche Management (SNM), which advocates the creation of protected space to experiment with radically new sustainable socio-technical practices. This paper contributes by asking whether this approach is also useful for analysis and governance of other types of socially desirable change. This question is addressed through a review of six key-findings of Strategic Niche Management and an original case study in the field of Near Field Communication (NFC) technologies for mobile payment. The social value at stake in this case is not sustainability but privacy. We draw three main conclusions. First, we find that the key-findings and concepts in SNM for sustainability are helpful to understand and interpret much of the data collected for the NFC case and privacy. However, there are notable differences in each of the key-findings, i.e findings related to a) the local-global distinction in SNM, b) expectations, c) social networks, d) learning, e) protection, and f) niche-regime interactions. Second, in relation to governance, the role of sustainability values (being a promising value to pursue) and privacy values (being a bottom-line value to defend) are notably different. Third, these differences result in different roles of public bodies in niche development. The paper ends with discussing the consequences for SNM for sustainability research and future research topics.Strategic Niche Management, sustainability, NFC, mobile payment, privacy

    Modeling and Optimization of Radio Frequency Identification Networks for Inventory Management

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    Stock loss and out-of-stocks are outcomes of poorly designed inventory management systems and can lead to significant revenue losses. Inventory management systems (IMSs) based on radio frequency identification (RFID) have the potential to minimize these losses if they are properly designed and deployed. However, the placement of RFID readers to support IMSs is often done on a trial and error basis which is time consuming and results in less than optimal coverage. A methodology to find the optimal location and number of RFID readers in a warehouse facility to ensure a desired level of radio frequency signal coverage was developed in this research. The results show that the proposed methodology works very well when applied to small rectangular facilities and small inverted-T facilities. However, some limitations exist when the method is applied to large facilities

    Sensor data-based decision making

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    Increasing globalization and growing industrial system complexity has amplified the interest in the use of information provided by sensors as a means of improving overall manufacturing system performance and maintainability. However, utilization of sensors can only be effective if the real-time data can be integrated into the necessary business processes, such as production planning, scheduling and execution systems. This integration requires the development of intelligent decision making models that can effectively process the sensor data into information and suggest appropriate actions. To be able to improve the performance of a system, the health of the system also needs to be maintained. In many cases a single sensor type cannot provide sufficient information for complex decision making including diagnostics and prognostics of a system. Therefore, a combination of sensors should be used in an integrated manner in order to achieve desired performance levels. Sensor generated data need to be processed into information through the use of appropriate decision making models in order to improve overall performance. In this dissertation, which is presented as a collection of five journal papers, several reactive and proactive decision making models that utilize data from single and multi-sensor environments are developed. The first paper presents a testbed architecture for Auto-ID systems. An adaptive inventory management model which utilizes real-time RFID data is developed in the second paper. In the third paper, a complete hardware and inventory management solution, which involves the integration of RFID sensors into an extremely low temperature industrial freezer, is presented. The last two papers in the dissertation deal with diagnostic and prognostic decision making models in order to assure the healthy operation of a manufacturing system and its components. In the fourth paper a Mahalanobis-Taguchi System (MTS) based prognostics tool is developed and it is used to estimate the remaining useful life of rolling element bearings using data acquired from vibration sensors. In the final paper, an MTS based prognostics tool is developed for a centrifugal water pump, which fuses information from multiple types of sensors in order to take diagnostic and prognostics decisions for the pump and its components --Abstract, page iv
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