The Experts below are selected from a list of 55707 Experts worldwide ranked by ideXlab platform
Vassilis Kostakos - One of the best experts on this subject based on the ideXlab platform.
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CHI - Monetary Assessment of Battery Life on Smartphones
Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 2016Co-Authors: Simo Hosio, Denzil Ferreira, Jorge Goncalves, Niels Van Berkel, Chu Luo, Muzamil Ahmed, Huber Flores, Vassilis KostakosAbstract:Research claims that users value the Battery Life of their smartphones, but no study to date has attempted to quantify Battery value and how this value changes according to users' current context and needs. Previous work has quantified the monetary value that smartphone users place on their data (e.g., location), but not on Battery Life. Here we present a field study and methodology for systematically measuring the monetary value of smartphone Battery Life, using a reverse second-price sealed-bid auction protocol. Our results show that the prices for the first and last 10% Battery segments differ substantially. Our findings also quantify the tradeoffs that users consider in relation to Battery, and provide a monetary model that can be used to measure the value of apps and enable fair ad-hoc sharing of smartphone resources.
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Understanding human-smartphone concerns: A study of Battery Life
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2011Co-Authors: Denzil Ferreira, Anind K Dey, Vassilis KostakosAbstract:This paper presents a large, 4-week study of more than 4000 people to assess their smartphone charging habits to identify timeslots suitable for opportunistic data uploading and power intensive operations on such devices, as well as opportunities to provide interventions to support better charging behavior. The paper provides an overview of our study and how it was conducted using an online appstore as a software deployment mechanism, and what Battery information was collected. We then describe how people charge their smartphones, the implications on Battery Life and energy usage, and discuss how to improve users' experience with Battery Life.
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Pervasive - Understanding human-smartphone concerns: a study of Battery Life
Lecture Notes in Computer Science, 2011Co-Authors: Denzil Ferreira, Anind K Dey, Vassilis KostakosAbstract:This paper presents a large, 4-week study of more than 4000 people to assess their smartphone charging habits to identify timeslots suitable for opportunistic data uploading and power intensive operations on such devices, as well as opportunities to provide interventions to support better charging behavior. The paper provides an overview of our study and how it was conducted using an online appstore as a software deployment mechanism, and what Battery information was collected. We then describe how people charge their smartphones, the implications on Battery Life and energy usage, and discuss how to improve users' experience with Battery Life.
Rebecca Carter - One of the best experts on this subject based on the ideXlab platform.
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optimizing for efficiency or Battery Life in a Battery supercapacitor electric vehicle
IEEE Transactions on Vehicular Technology, 2012Co-Authors: Rebecca Carter, Andrew Cruden, Peter HallAbstract:A novel energy control strategy for a Battery/supercapacitor vehicle, which is designed to be tunable to achieve different goals, is described. Two possible goals for adding a pack of supercapacitors are examined for a test vehicle using lead-acid batteries: 1) improving the vehicle's efficiency and range and 2) reducing the peak currents in the Battery pack to increase Battery Life. The benefits of hybridization are compared with those achievable by increasing the size of the Battery pack by a comparable mass to the supercapacitors. The availability of energy from regenerative braking and the characteristics of the supercapacitors are considered as impact factors. Supercapacitors were found to be effective at reducing peak Battery currents; however, the benefits to range extension were found to be limited. A Battery Life extension of at least 50% is necessary to make supercapacitors cost effective for the test vehicle at current prices.
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Optimizing for efficiency or Battery Life in a Battery/supercapacitor electric vehicle
IEEE Transactions on Vehicular Technology, 2012Co-Authors: Rebecca Carter, Andrew Cruden, Peter J HallAbstract:A novel energy control strategy for a Battery/supercapacitor vehicle, which is designed to be tunable to achieve different goals, is described. Two possible goals for adding a pack of supercapacitors are examined for a test vehicle using lead-acid batteries: 1) improving the vehicle's efficiency and range and 2) reducing the peak currents in the Battery pack to increase Battery Life. The benefits of hybridization are compared with those achievable by increasing the size of the Battery pack by a comparable mass to the supercapacitors. The availability of energy from regenerative braking and the characteristics of the supercapacitors are considered as impact factors. Supercapacitors were found to be effective at reducing peak Battery currents; however, the benefits to range extension were found to be limited. A Battery Life extension of at least 50% is necessary to make supercapacitors cost effective for the test vehicle at current prices.
Denzil Ferreira - One of the best experts on this subject based on the ideXlab platform.
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CHI - Monetary Assessment of Battery Life on Smartphones
Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems, 2016Co-Authors: Simo Hosio, Denzil Ferreira, Jorge Goncalves, Niels Van Berkel, Chu Luo, Muzamil Ahmed, Huber Flores, Vassilis KostakosAbstract:Research claims that users value the Battery Life of their smartphones, but no study to date has attempted to quantify Battery value and how this value changes according to users' current context and needs. Previous work has quantified the monetary value that smartphone users place on their data (e.g., location), but not on Battery Life. Here we present a field study and methodology for systematically measuring the monetary value of smartphone Battery Life, using a reverse second-price sealed-bid auction protocol. Our results show that the prices for the first and last 10% Battery segments differ substantially. Our findings also quantify the tradeoffs that users consider in relation to Battery, and provide a monetary model that can be used to measure the value of apps and enable fair ad-hoc sharing of smartphone resources.
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Understanding human-smartphone concerns: A study of Battery Life
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2011Co-Authors: Denzil Ferreira, Anind K Dey, Vassilis KostakosAbstract:This paper presents a large, 4-week study of more than 4000 people to assess their smartphone charging habits to identify timeslots suitable for opportunistic data uploading and power intensive operations on such devices, as well as opportunities to provide interventions to support better charging behavior. The paper provides an overview of our study and how it was conducted using an online appstore as a software deployment mechanism, and what Battery information was collected. We then describe how people charge their smartphones, the implications on Battery Life and energy usage, and discuss how to improve users' experience with Battery Life.
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Pervasive - Understanding human-smartphone concerns: a study of Battery Life
Lecture Notes in Computer Science, 2011Co-Authors: Denzil Ferreira, Anind K Dey, Vassilis KostakosAbstract:This paper presents a large, 4-week study of more than 4000 people to assess their smartphone charging habits to identify timeslots suitable for opportunistic data uploading and power intensive operations on such devices, as well as opportunities to provide interventions to support better charging behavior. The paper provides an overview of our study and how it was conducted using an online appstore as a software deployment mechanism, and what Battery information was collected. We then describe how people charge their smartphones, the implications on Battery Life and energy usage, and discuss how to improve users' experience with Battery Life.
Wen-yew Liang - One of the best experts on this subject based on the ideXlab platform.
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A study on Battery Life tradeoff between deep sleep and sleep modes of an actual PDA
2008 3rd IEEE Conference on Industrial Electronics and Applications, 2008Co-Authors: Shanq-jang Ruan, Kun-lin Tsai, Wen-yew LiangAbstract:Extending the Battery Life time for Battery-powered devices has become a critical issue for portable system designers. This paper presents a comprehensive study of sleep and deep sleep modes on power consumption of an actual PDA. Our work is based on the concept that the effect use of each componentpsilas power saving mode can significantly reduce total power consumption in a PDA. In our experiments, we measured the current of each power rail of a real PDA to explore how much power is consumed by each power rail for the different modes. We measured the total power for playing a WMV file as well as for idle and system off modes. The results of this study show that a system CPU can save 16.9% in Battery Life by switching to deep sleep mode rather than sleep mode. With the understanding provided by this analysis, designers can extend Battery Life time by better managing the fixed amount of energy provided by the Battery.
Jeremy J Michalek - One of the best experts on this subject based on the ideXlab platform.
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plug in hybrid electric vehicle Lifepo4 Battery Life implications of thermal management driving conditions and regional climate
Journal of Power Sources, 2017Co-Authors: Tugce Yuksel, Shawn Litster, Venkatasubramanian Viswanathan, Jeremy J MichalekAbstract:Battery degradation strongly depends on temperature, and many plug-in electric vehicle applications employ thermal management strategies to extend Battery Life. The effectiveness of thermal management depends on the design of the thermal management system as well as the Battery chemistry, cell and pack design, vehicle system characteristics, and operating conditions. We model a plug-in hybrid electric vehicle with an air-cooled Battery pack composed of cylindrical LifePO4/graphite cells and simulate the effect of thermal management, driving conditions, regional climate, and vehicle system design on Battery Life. We estimate that in the absence of thermal management, aggressive driving can cut Battery Life by two thirds; a blended gas/electric-operation control strategy can quadruple Battery Life relative to an all-electric control strategy; larger Battery packs can extend Life by an order of magnitude relative to small packs used for all-electric operation; and batteries last 73–94% longer in mild-weather San Francisco than in hot Phoenix. Air cooling can increase Battery Life by a factor of 1.5–6, depending on regional climate and driving patterns. End of Life criteria has a substantial effect on Battery Life estimates.
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Development of a Simulation Model to Analyze the Effect of Thermal Management on Battery Life
SAE Technical Paper Series, 2012Co-Authors: Tugce Yuksel, Jeremy J MichalekAbstract:Battery Life and performance depend strongly on temperature; thus there exists a need for thermal conditioning in plug-in vehicle applications. The effectiveness of thermal management in extending Battery Life depends on the design of thermal management used as well as the specific Battery chemistry, cell and pack design, vehicle system characteristics, and operating conditions. We examine the case of an air cooled plug-in hybrid electric vehicle Battery pack with cylindrical LifePO4/graphite cell design and address the question: How much improvement in Battery Life can be obtained with passive air cooling? To answer this question, a model is constructed consisting of a thermal model that calculates temperature change in the Battery and a degradation model that estimates capacity loss. A driving and storage profile is constructed and simulated in two cities Miami and Phoenix - which have different seasonal temperatures. The results suggest that air cooling may extend Battery Life by 5% in Miami, characterized by higher average temperatures, and by 23% in Phoenix, characterized by higher peak temperatures. Thus, thermal management appears to have the greatest effect in regions with high peak temperatures, even if the region has lower average temperatures.
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Evaluation of the Effects of Thermal Management on Battery Life in Plug-in Hybrid Electric Vehicles
2012Co-Authors: Tugce Yuksel, Jeremy J MichalekAbstract:We develop a simulation model that aims to evaluate the effect of thermal management on Battery Life. The model consists of two submodels: a thermal model and a Battery degradation model. The temperature rise in the Battery is calculated using the thermal model, and a temperature profile is obtained under pre-defined driving, charging and stand-by scenarios. The temperature profile and the energy requirement required to achieve a driving profile act as inputs to the degradation sub-model, which is used to predict the Battery Life. The degradation model is derived from models and test data available in literature, and the model is constructed for aircooled cylindrical LifePO4 cells based on the Hymotion Prius-conversion configuration. Preliminary results suggest that peak temperatures have the greatest impact on degradation: Thermal management increases Life substantially in climates with high peak temperatures (Pheonix) and for more aggressive driving cycles (US06), while thermal management has less influence in climates with lower peak temperatures (Miami) and with gentle driving cycles (UDDS). Use of cabin air vs. outside air for thermal management has minor impact on Battery Life for the control strategy used, but thermostat control settings are important for lowering peak temperatures and extending Battery Life. Introduction Plug-in hybrid electric vehicles (PHEVs) have the potential to reduce operating cost, greenhouse gas (GHG) emissions, and petroleum consumption in the transportation sector. One of the most important factors affecting the commercialization of PHEVs is the Battery cost, which should be reduced for PHEVs to be cost competitive with other vehicles [2-5]. While reducing the cost, other requirements should also be satisfied such as power, energy, weight, size, and Life. Often, improving one of these factors causes an adverse effect in others. If the Battery reaches end of Life (EOL) before vehicle Life, there would be need for Battery replacement, which raises the costs for the consumer substantially since the Battery is the most expensive part of the vehicle for many electrified vehicles. Although different design choices can lead to different Battery EOL criteria [6], EOL is typically defined as the time when 20% capacity loss or 30% internal resistance growth is reached. According to the goals set by US Advanced Battery Consortium (USABC), a PHEV Battery is targeted to have 15 years of calendar Life and 300,000 cycles of cycle Life One of these stress factors that strongly affects degradation rate is temperature. The relationship between degradation and temperature can be formulated by an Arrhenius type behavior where degradation rate increases exponentially with temperature [7]. To achieve these goals, it is necessary to improve Battery Life by managing the stress factors that affect Battery Life.
