36 resultados para Electromechanical devices.


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Reinforcing the Low Voltage (LV) distribution network will become essential to ensure it remains within its operating constraints as demand on the network increases. The deployment of energy storage in the distribution network provides an alternative to conventional reinforcement. This paper presents a control methodology for energy storage to reduce peak demand in a distribution network based on day-ahead demand forecasts and historical demand data. The control methodology pre-processes the forecast data prior to a planning phase to build in resilience to the inevitable errors between the forecasted and actual demand. The algorithm uses no real time adjustment so has an economical advantage over traditional storage control algorithms. Results show that peak demand on a single phase of a feeder can be reduced even when there are differences between the forecasted and the actual demand. In particular, results are presented that demonstrate when the algorithm is applied to a large number of single phase demand aggregations that it is possible to identify which of these aggregations are the most suitable candidates for the control methodology.

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In recent years, ZigBee has been proven to be an excellent solution to create scalable and flexible home automation networks. In a home automation network, consumer devices typically collect data from a home monitoring environment and then transmit the data to an end user through multi-hop communication without the need for any human intervention. However, due to the presence of typical obstacles in a home environment, error-free reception may not be possible, particularly for power constrained devices. A mobile sink based data transmission scheme can be one solution but obstacles create significant complexities for the sink movement path determination process. Therefore, an obstacle avoidance data routing scheme is of vital importance to the design of an efficient home automation system. This paper presents a mobile sink based obstacle avoidance routing scheme for a home monitoring system. The mobile sink collects data by traversing through the obstacle avoidance path. Through ZigBee based hardware implementation and verification, the proposed scheme successfully transmits data through the obstacle avoidance path to improve network performance in terms of life span, energy consumption and reliability. The application of this work can be applied to a wide range of intelligent pervasive consumer products and services including robotic vacuum cleaners and personal security robots1.

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This paper reports findings from six field courses about student’s perceptions of iPads as mobile learning devices for fieldwork. Data were collected through surveys and focus groups. The key findings suggest that the multi-tool nature of the iPads and their portability were the main strengths. Students had some concerns over the safety of the iPads in adverse weather and rugged environments, though most of these concerns were eliminated after using the devices with protective cases. Reduced connectivity was found to be one of the main challenges for mobile learning. Finally, students and practitioners views of why they used the mobile devices for fieldwork did not align.

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Mobile devices can enhance undergraduate research projects and students’ research capabilities. The use of mobile devices such as tablet computers will not automatically make undergraduates better researchers, but their use should make investigations, writing, and publishing more effective and may even save students time. We have explored some of the possibilities of using “tablets” and “smartphones” to aid the research and inquiry process in geography and bioscience fieldwork. We provide two case studies as illustration of how students working in small research groups use mobile devices to gather and analyze primary data in field-based inquiry. Since April 2010, Apple’s iPad has changed the way people behave in the digital world and how they access their music, watch videos, or read their email much as the entrepreneurs Steve Jobs and Jonathan Ive intended. Now with “apps” and “the cloud” and the ubiquitous references to them appearing in the press and on TV, academics’ use of tablets is also having an impact on education and research. In our discussion we will refer to use of smartphones such as the iPhone, iPod, and Android devices under the term “tablet”. Android and Microsoft devices may not offer the same facilities as the iPad/iphone, but many app producers now provide versions for several operating systems. Smartphones are becoming more affordable and ubiquitous (Melhuish and Falloon 2010), but a recent study of undergraduate students (Woodcock et al. 2012, 1) found that many students who own smartphones are “largely unaware of their potential to support learning”. Importantly, however, students were found to be “interested in and open to the potential as they become familiar with the possibilities” (Woodcock et al. 2012). Smartphones and iPads could be better utilized than laptops when conducting research in the field because of their portability (Welsh and France 2012). It is imperative for faculty to provide their students with opportunities to discover and employ the potential uses of mobile devices in their learning. However, it is not only the convenience of the iPad or tablet devices or smartphones we wish to promote, but also a way of thinking and behaving digitally. We essentially suggest that making a tablet the center of research increases the connections between related research activities.

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A Universal Serial Bus (USB) Mass Storage Device (MSD), often termed a USB flash drive, is ubiquitously used to store important information in unencrypted binary format. This low cost consumer device is incredibly popular due to its size, large storage capacity and relatively high transfer speed. However, if the device is lost or stolen an unauthorized person can easily retrieve all the information. Therefore, it is advantageous in many applications to provide security protection so that only authorized users can access the stored information. In order to provide security protection for a USB MSD, this paper proposes a session key agreement protocol after secure user authentication. The main aim of this protocol is to establish session key negotiation through which all the information retrieved, stored and transferred to the USB MSD is encrypted. This paper not only contributes an efficient protocol, but also does not suffer from the forgery attack and the password guessing attack as compared to other protocols in the literature. This paper analyses the security of the proposed protocol through a formal analysis which proves that the information is stored confidentially and is protected offering strong resilience to relevant security attacks. The computational cost and communication cost of the proposed scheme is analyzed and compared to related work to show that the proposed scheme has an improved tradeoff for computational cost, communication cost and security.

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Background: Health care literature supports the development of accessible interventions that integrate behavioral economics, wearable devices, principles of evidence-based behavior change, and community support. However, there are limited real-world examples of large scale, population-based, member-driven reward platforms. Subsequently, a paucity of outcome data exists and health economic effects remain largely theoretical. To complicate matters, an emerging area of research is defining the role of Superusers, the small percentage of unusually engaged digital health participants who may influence other members. Objective: The objective of this preliminary study is to analyze descriptive data from GOODcoins, a self-guided, free-to-consumer engagement and rewards platform incentivizing walking, running and cycling. Registered members accessed the GOODcoins platform through PCs, tablets or mobile devices, and had the opportunity to sync wearables to track activity. Following registration, members were encouraged to join gamified group challenges and compare their progress with that of others. As members met challenge targets, they were rewarded with GOODcoins, which could be redeemed for planet- or people-friendly products. Methods: Outcome data were obtained from the GOODcoins custom SQL database. The reporting period was December 1, 2014 to May 1, 2015. Descriptive self-report data were analyzed using MySQL and MS Excel. Results: The study period includes data from 1298 users who were connected to an exercise tracking device. Females consisted of 52.6% (n=683) of the study population, 33.7% (n=438) were between the ages of 20-29, and 24.8% (n=322) were between the ages of 30-39. 77.5% (n=1006) of connected and active members met daily-recommended physical activity guidelines of 30 minutes, with a total daily average activity of 107 minutes (95% CI 90, 124). Of all connected and active users, 96.1% (n=1248) listed walking as their primary activity. For members who exchanged GOODcoins, the mean balance was 4,000 (95% CI 3850, 4150) at time of redemption, and 50.4% (n=61) of exchanges were for fitness or outdoor products, while 4.1% (n=5) were for food-related items. Participants were most likely to complete challenges when rewards were between 201-300 GOODcoins. Conclusions: The purpose of this study is to form a baseline for future research. Overall, results indicate that challenges and incentives may be effective for connected and active members, and may play a role in achieving daily-recommended activity guidelines. Registrants were typically younger, walking was the primary activity, and rewards were mainly exchanged for fitness or outdoor products. Remaining to be determined is whether members were already physically active at time of registration and are representative of healthy adherers, or were previously inactive and were incentivized to change their behavior. As challenges are gamified, there is an opportunity to investigate the role of superusers and healthy adherers, impacts on behavioral norms, and how cooperative games and incentives can be leveraged across stratified populations. Study limitations and future research agendas are discussed.