| 1. |
- Ekström, Martin, 1980-, et al.
(författare)
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A Bluetooth Radio Energy Consumption Model for Low Duty-Cycle Applications
- 2012
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 61:3, s. 609-617
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a realistic model of the radio energy consumption for Bluetooth-equipped sensor nodes used in a low-duty-cycle network. The model is based on empirical energy consumption measurements of Bluetooth modules. This model will give users the possibility to optimize their radio communication with respect to energy consumption while sustaining the data rate. This paper shows that transmission power cannot always be directly related to energy consumption. Measurements indicate that, when the transmission power ranges from $-$5 to $+$10 dBm, the difference in consumed energy can be detected for each transmission peak in the sniff peak. However, the change is negligible for the overall energy consumption. The nonlinear behavior of the idle state for both master and slave when increasing the interval and number of attempts is presented. The energy consumption for a master node is in direct relation to the number of slaves and will increase by approximately 50% of the consumption of one slave per additional slave, regardless of the radio setting.
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| 2. |
- Ekström, Martin, 1980-, et al.
(författare)
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Comparison study of ZigBee and Bluetooth with regards to power consumption, packet-error-rate and distance
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper present a empirical measurement comparison study of ZigBee and Bluetooth. The parameters investigated are power consumption, packet-error-rate or retransmissions and distance in different environments. This study shows the differences and similarities for the two different short range radio technologies. A measurement set-up and procedure that makes it possible to investigate power consumption of the radio module, retransmissions and packet-error-rate as well as ambient noise is presented. For both the Bluetooth and the ZigBee modules used in this study the distance itself have no influence of the power consumption. However the retransmission rate and packet-error-rate have a large influence on the power consumption. This study have show that the environment has a great impact on the range of the radio modules and the behaviour concerning the retransmission rate and packet-error-rate.
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| 3. |
- Ekström, Martin, 1980-, et al.
(författare)
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Development of Programmable Micro Power Meter Testbed for Radio Modules
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the POMPOM testbed for high precision power consumption \textit{in situ} measurements for interchangeable radio modules.The main requirements for the development have been;Interchangeable radio modules to enable the same hardware testbed to be used independently of the radio standard used make comparison studies possible.The testbed should be programmable so that the need for hardware development should be minimized. The testbed must be able to act as a controller for the communication and simultaneously make accurate \textit{in situ} measurements of the energy consumption of the radio.The required sample rate must be at least 50 kSamples per second. The range of the current measurement should cover at least 0.2~$\mu$Ampere to 60~mAmpere with at least 14-bit resolution.Mobility, low cost and small size are vital for the testbed. It must be possible to deploy several measurement testbeds to act as sensor nodes in a wireless sensor network to capture the behavior of the entire network.The results for test measurement setup for POMPOM is presented to illustrate a typical usage of the testbed. The results presented show how the testbed can be used to investigate the correlation between distance, packet-error-rate and current consumption for a Zigbee radio.
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| 4. |
- Tews, Ingo, et al.
(författare)
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Nuclear Forces for Precision Nuclear Physics: A Collection of Perspectives
- 2022
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Ingår i: Few-Body Systems. - : Springer Science and Business Media LLC. - 1432-5411 .- 0177-7963. ; 63:4
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Tidskriftsartikel (refereegranskat)abstract
- This is a collection of perspective pieces contributed by the participants of the Institute for Nuclear Theory's Program on Nuclear Physics for Precision Nuclear Physics which was held virtually from April 19 to May 7, 2021. The collection represents the reflections of a vibrant and engaged community of researchers on the status of theoretical research in low-energy nuclear physics, the challenges ahead, and new ideas and strategies to make progress in nuclear structure and reaction physics, effective field theory, lattice QCD, quantum information, and quantum computing. The contributed pieces solely reflect the perspectives of the respective authors and do not represent the viewpoints of the Institute for Nuclear theory or the organizers of the program.
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| 5. |
- Aref, Thomas, 1980, et al.
(författare)
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Quantum Acoustics with Surface Acoustic Waves
- 2016
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Ingår i: Superconducting Devices in Quantum Optics. - Cham : Springer International Publishing. - 9783319240916 ; , s. 217-244
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- It has recently been demonstrated that surface acoustic waves (SAWs) can interact with superconducting qubits at the quantum level. SAW resonators in the GHz frequency range have also been found to have low loss at temperatures compatible with superconducting quantum circuits. These advances open up new possibilities to use the phonon degree of freedom to carry quantum information. In this chapter, we give a description of the basic SAW components needed to develop quantum circuits, where propagating or localized SAW-phonons are used both to study basic physics and to manipulate quantum information. Using phonons instead of photons offers new possibilities which make these quantum acoustic circuits very interesting. We discuss general considerations for SAW experiments at the quantum level and describe experiments both with SAW resonators and with interaction between SAWs and a qubit. We also discuss several potential future developments.
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| 6. |
- Ekström, Martin, 1980-
(författare)
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Towards Predictable and Reliable Wireless Communication in Harsh Environments
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wireless communication in industrial, scientific and medical applications have several benefits. The main benefits when using wireless technologies include ease-of-deployment, the simplicity to introduce new units into the network and mobility. However it also put higher demands on the communication, including reliability and predictability compared to wired communication. The reliability issues correlate to the radio communication and the possibility to ensure that the user data is received, and within the time frame of the system requirements. This doctoral thesis presents an empirical measurement approach to investigate and model the behaviour linked to reliability and predictability. The focus of the work presented is energy consumption, packet-error-rate and latency studies. This is performed for various radio technologies and standards in (radio?) harsh environments. The main contributions of this thesis are the measurements platforms and procedures that have been developed to meet the requirements to investigate modern radio technologies in terms of predictability and reliability. This thesis show that it is possible to predict wireless communication in radio harsh environments. However it is necessary to determine the characteristics of the environment to be able to choose a suitable radio technology. The measurement procedures presented in this thesis alongside the platform developed enable these types of investigations. In this thesis a model of the energy consumption for a Bluetooth radio in low-duty-cycle applications with point-to-multipoint communication is presented. The measurements show that distance and transmission power will not effect the energy consumption for a Bluetooth nor ZigBee module. However the packet-error-rate and number of retransmissions will affect the overall energy consumption, and these parameters can be correlated to distance and foremost the environmental characteristics. This thesis also presents two application-based solutions, a time synchronized ECG network with reliable data communication as well as a low-latency wireless I/O for a hydro plant.
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| 7. |
- Gustafsson, Martin, 1979, et al.
(författare)
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Propagating phonons coupled to an artificial atom
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6206, s. 207-211
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Tidskriftsartikel (refereegranskat)abstract
- Quantum information can be stored in micromechanical resonators, encoded as quanta of vibration known as phonons. The vibrational motion is then restricted to the stationary eigenmodes of the resonator, which thus serves as local storage for phonons. In contrast, we couple propagating phonons to an artificial atom in the quantum regime and reproduce findings from quantum optics with sound taking over the role of light. Our results highlight the similarities between phonons and photons but also point to new opportunities arising from the unique features of quantum mechanical sound. The low propagation speed of phonons should enable new dynamic schemes for processing quantum information, and the short wavelength allows regimes of atomic physics to be explored that cannot be reached in photonic systems.
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| 8. |
- Lindborg, Ann-Louise, 1979-
(författare)
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Usability Requirements for User-Controlled Robotic Eating Aids
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The meal is fundamental in terms of nutrition but also from a social perspective. To be able to eat independently is described as important for the meal experience. The development of a robotic eating aid called Bestic and the evolvement of a list of usability criteria for such an aid are described in this thesis. The work has been ongoing for 16 years. Bestic has been developed through user centred design, an iterative process with reoccurring evaluations and development. The design principle “it is not supposed just to work, but to be worth using” has guided the work. The feedback provided by the users throughout this process has had a great impact on the strategic choices of which features to prioritize during further development and what to keep as it is and has contributed to the list of usability requirements for robotic eating aids. The context in which the robotic eating aid is used is of importance for the usability requirements. To further understand the environment that the robotic eating aid is used in, studies about the meal situation for older people in both Scandinavian/Swedish and Japanese contexts were conducted. The secondary users (care professionals or next of kin) were also taken into consideration when deriving the usability requirements and while performing the evaluations of the robotic eating aid.The most important research outcome from this work is a list of usability requirements for robotic eating aids. The requirements are divided into functional requirements and social requirements. The functional requirements for robotic eating aids include:· how well they work to eat with· how they are controlled· safety aspects· portability· possibility to adapt to different users. The social requirements for robotic eating aids include:· how to fit into the meal situation· not to disturb the conversation· the needs from secondary users.
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| 9. |
- Lu, Hsuan Hao, et al.
(författare)
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Simulations of subatomic many-body physics on a quantum frequency processor
- 2019
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Ingår i: Physical Review A. - 2469-9934 .- 2469-9926. ; 100:1
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Tidskriftsartikel (refereegranskat)abstract
- Simulating complex many-body quantum phenomena is a major scientific impetus behind the development of quantum computing, and a range of technologies are being explored to address such systems. We present the results of the largest photonics-based simulation to date, applied in the context of subatomic physics. Using an all-optical quantum frequency processor, the ground-state energies of light nuclei including the triton (H3), He3, and the alpha particle (He4) are computed. Complementing these calculations and utilizing a 68-dimensional Hilbert space, our photonic simulator is used to perform subnucleon calculations of the two- and three-body forces between heavy mesons in the Schwinger model. This work is a first step in simulating subatomic many-body physics on quantum frequency processors - augmenting classical computations that bridge scales from quarks to nuclei.
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| 10. |
- Lu, Hsuan Hao, et al.
(författare)
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Subatomic many-body physics simulations on a quantum frequency processor
- 2019
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; Part F128-CLEO_QELS 2019
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a photonic quantum simulation on a quantum frequency processor, computing the effective interaction potential between composite particles in the Schwinger model and determining the binding energies of three nuclei (3H, 3He, and 4He).
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