1,808 research outputs found
Optimal Checkpointing for Secure Intermittently-Powered IoT Devices
Energy harvesting is a promising solution to power Internet of Things (IoT)
devices. Due to the intermittent nature of these energy sources, one cannot
guarantee forward progress of program execution. Prior work has advocated for
checkpointing the intermediate state to off-chip non-volatile memory (NVM).
Encrypting checkpoints addresses the security concern, but significantly
increases the checkpointing overheads. In this paper, we propose a new online
checkpointing policy that judiciously determines when to checkpoint so as to
minimize application time to completion while guaranteeing security. Compared
to state-of-the-art checkpointing schemes that do not account for the overheads
of encrypted checkpoints we improve execution time up to 1.4x.Comment: ICCAD 201
Wearable flexible lightweight modular RFID tag with integrated energy harvester
A novel wearable radio frequency identification (RFID) tag with sensing, processing, and decision-taking capability is presented for operation in the 2.45-GHz RFID superhigh frequency (SHF) band. The tag is powered by an integrated light harvester, with a flexible battery serving as an energy buffer. The proposed active tag features excellent wearability, very high read range, enhanced functionality, flexible interfacing with diverse low-power sensors, and extended system autonomy through an innovative holistic microwave system design paradigm that takes antenna design into consideration from the very early stages. Specifically, a dedicated textile shorted circular patch antenna with monopolar radiation pattern is designed and optimized for highly efficient and stable operation within the frequency band of operation. In this process, the textile antenna's functionality is augmented by reusing its surface as an integration platform for light-energy-harvesting, sensing, processing, and transceiver hardware, without sacrificing antenna performance or the wearer's comfort. The RFID tag is validated by measuring its stand-alone and on-body characteristics in free-space conditions. Moreover, measurements in a real-world scenario demonstrate an indoor read range up to 23 m in nonline-of-sight indoor propagation conditions, enabling interrogation by a reader situated in another room. In addition, the RFID platform only consumes 168.3 mu W, when sensing and processing are performed every 60 s
Solar Energy Harvesting to Improve Capabilities of Wearable Devices
The market of wearable devices has been growing over the past decades. Smart wearables
are usually part of IoT (Internet of things) systems and include many functionalities such as
physiological sensors, processing units and wireless communications, that are useful in fields like
healthcare, activity tracking and sports, among others. The number of functions that wearables
have are increasing all the time. This result in an increase in power consumption and more frequent
recharges of the battery. A good option to solve this problem is using energy harvesting so that the
energy available in the environment is used as a backup power source. In this paper, an energy
harvesting system for solar energy with a flexible battery, a semi-flexible solar harvester module and
a BLE (Bluetooth® Low Energy) microprocessor module is presented as a proof-of-concept for the
future integration of solar energy harvesting in a real wearable smart device. The designed device
was tested under different circumstances to estimate the increase in battery lifetime during common
daily routines. For this purpose, a procedure for testing energy harvesting solutions, based on solar
energy, in wearable devices has been proposed. The main result obtained is that the device could
permanently work if the solar cells received a significant amount of direct sunlight for 6 h every day.
Moreover, in real-life scenarios, the device was able to generate a minimum and a maximum power
of 27.8 mW and 159.1 mW, respectively. For the wearable system selected, Bindi, the dynamic tests
emulating daily routines has provided increases in the state of charge from 19% (winter cloudy days,
4 solar cells) to 53% (spring sunny days, 2 solar cells).
Keywords: energy harvesting; internet of things; physiologicalThis research was funded by the Department of Research and Innovation of Madrid
Regional Authority, in the EMPATIA-CM research project (reference Y2018/TCS-5046). This work has
been partially supported by the European Union—NextGenerationEU, with the SAPIENTIAE4BINDI
project “Proof of Concept” 2021. (Ref: PDC2021-121071-I00/AEI/10.13039/501100011033). This
work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the
Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M26),
and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)
PhyNetLab: An IoT-Based Warehouse Testbed
Future warehouses will be made of modular embedded entities with
communication ability and energy aware operation attached to the traditional
materials handling and warehousing objects. This advancement is mainly to
fulfill the flexibility and scalability needs of the emerging warehouses.
However, it leads to a new layer of complexity during development and
evaluation of such systems due to the multidisciplinarity in logistics,
embedded systems, and wireless communications. Although each discipline
provides theoretical approaches and simulations for these tasks, many issues
are often discovered in a real deployment of the full system. In this paper we
introduce PhyNetLab as a real scale warehouse testbed made of cyber physical
objects (PhyNodes) developed for this type of application. The presented
platform provides a possibility to check the industrial requirement of an
IoT-based warehouse in addition to the typical wireless sensor networks tests.
We describe the hardware and software components of the nodes in addition to
the overall structure of the testbed. Finally, we will demonstrate the
advantages of the testbed by evaluating the performance of the ETSI compliant
radio channel access procedure for an IoT warehouse
A Combined 90/900 MHz IC Architecture for Smart Tag Application
In this work we present a combined 90/900 MHz Energy Harvesting Architecture for active smart tag Application. The harvester takes advantages from a dedicated diplexer and a power manager for battery life enhancement purposes. The system has been optimized in the 900 MHz frequency range by analyzing a probabilistic approach used for modeling the possible amount of Global System for Mobile communication (GSM) energy that could be harvested while a fixed power downlink scenario has been adopted for the 90MHz band. A preliminary IC system with a 0.18ÎĽm CMOS SMIC technology has been designed and optimized at 90 and 900 MHz while discrete element board, to be integrated with the proposed IC, with commercial components has been developed and tested. Concerning simulation results on the IC design they have confirmed that the integrated system handles an incoming power typically ranging from -25 dBm to 5 dBm by rectifying the variable input signals into a DC voltage source with an average 50% efficiency
- …