Droop control is used for power management in DC grids. Based on the level of the DC grid voltage, the amount of power regulated to or from the appliance is regulated such, that power management is possible. The Universal 4 Leg is a laboratory setup for studying the functionality of a grid manager for power management. It has four independent outputs that can be regulated with pulse width modulation to control the power flow between the DC grid and for example, a rechargeable battery, solar panel or any passive load like lighting or heating.
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In the past decade, the fast and transient coupling and uncoupling of functionally related brain regions into networks has received much attention in cognitive neuroscience. Empirical tools to study network coupling include functional magnetic resonance imaging (fMRI)-based functional and/or effective connectivity, and electroencephalography (EEG)/magnetoencephalography-based measures of neuronal synchronization. Here we use simultaneously recorded EEG and fMRI to assess whether fMRI-based connectivity and frequency-specific EEG power are related. Using data collected during resting state, we studied whether posterior EEG alpha power fluctuations are correlated with connectivity within the visual network and between the visual cortex and the rest of the brain. The results show that when alpha power increases, BOLD connectivity between the primary visual cortex and occipital brain regions decreases and that the negative relation of the visual cortex with the anterior/medial thalamus decreases and the ventral–medial prefrontal cortex is reduced in strength. These effects were specific for the alpha band, and not observed in other frequency bands. The decreased connectivity within the visual system may indicate an enhanced functional inhibition during a higher alpha activity. This higher inhibition level also attenuates long-range intrinsic functional antagonism between the visual cortex and the other thalamic and cortical regions. Together, these results illustrate that power fluctuations in posterior alpha oscillations result in local and long-range neural connectivity changes.
LINK
In this paper, we experimentally compare orthogonal frequency-division multiplexing (OFDM) and on-off keying (OOK) modulation in the context of the IEEE 802.15.13-2023 standard at bandwidths up to 50 MHz across a Li-Fi link with distances up to 5 m and a lateral offset up to 51°. Error vector magnitude (EVM) and bit error rate (BER) evaluations confirm that the high peak-to-average power ratio (PAPR) of OFDM limits the achievable transmission distance, but it offers higher data rates due to its higher spectral efficiency. Due to the lower PAPR, OOK-based Pulsed Modulation PHY (PM-PHY) shows a significantly higher link range. As the structure of the PM-PHY is based on OFDM symbols, the two solutions may also be combined to open a wider range of use cases for optical wireless communications.
LINK
The nonlinearity induced by light-emitting diodes in visible light communication (VLC) systems presents a challenge to the parametrization of orthogonal frequency division multiplexing (OFDM). The goal of the multi-objective optimization problem presented in this study is to maximize the transmitted power (superimposed LED bias-current and signal amplification) for both conventional and constant envelope (CE) OFDM while also maximizing spectral efficiency. The bit error rate (BER) metric is used to evaluate the optimization using the non-dominated sorting genetic algorithm II. Simulation results show that for a BER of 1×10 −3 , the signal-to-noise ratio (SNR) required decreases with the guard band due to intermodulation distortions. In contrast to SNR values of approximately 13 and 25 dB achieved by traditional OFDM-based systems, the VLC system with CE signals achieves a guard band of 6% of the signal bandwidth with required SNR values of approximately 10.8 and 24 dB for 4-quadrature amplitude modulation (QAM) and 16-QAM modulation orders, respectively.
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Research showed that more than 30% of patients with Posttraumatic Stress Disorder (PTSD) do not benefit from evidence- based treatments: Trauma-Focused Cognitive Behavioral Therapy (TF-CBT) or Eye Movement Desensitization and Reprocessing (EMDR). These are patients with prolonged and multiple traumatization, with poor verbal memory, and patients with emotional over-modulation. Retelling traumatic experiences in detail is poorly tolerated by these patients and might be a reason for not starting or not completing the recommended treatments. Due to lack of evidence, no alternative treatments are recommended yet. Art therapy may offer an alternative and suitable treatment, because the nonverbal and experiential character of art therapy appears to be an appropriate approach to the often wordless and visual nature of traumatic memories. The objective of this pilot study was to test the acceptability, feasibility, and applicability of trauma-focused art therapy for adults with PTSD due to multiple and prolonged traumatization (patients with early childhood traumatization and refugees from different cultures). Another objective was to identify the preliminary effectiveness of art therapy. Results showed willingness to participate and adherence to treatment of patients. Therapists considered trauma-focused art therapy feasible and applicable and patients reported beneficial effects, such as more relaxation, externalization of memories and emotions into artwork, less intrusive thoughts of traumatic experiences and more confidence in the future. The preliminary findings on PTSD symptom severity showed a decrease of symptoms in some participants, and an increase of symptoms in other participants. Further research into the effectiveness of art therapy and PTSD is needed.
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This study presents a methodology designed to optimize various parameters of each access point within a Multiple-Input Single-Output (MISO) Visible Light Communication (VLC) system. The primary objective is to enhance both power and spectral efficiencies. A MISO-VLC model is presented based on experimental evaluations and a problem formulation considering intermodulation distortions based on Orthogonal Frequency Division Multiplexing modulation. A Hybrid Multi-Objective Optimization (HMO) approach is proposed, combining the Non-Sorting Genetic Algorithm III (NSGA-III) and the Multi-objective Grey Wolf Optimization (MOGWO). The proposed HMO's success was validated by a 66 % reduction in transmitted power, maintaining the Error Vector Magnitude (EVM) performance metrics even at lower power transmission levels and minimizing the guard band to its lower bound.
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Studenten van Fontys Hogeschool ICT/Technische Informatica hebben vorig jaar hard gewerkt aan een minihovercraft. Die moest dienen als studieobject voor een aantal MKB'ers, die met een Raak Lightsubsidie meer informatie wilden inwinnen over het bouwen van toepassingen met embedded Linux en verschillende periferieën, waaronder WLan, USB-verbindingen, een afstandsbediening via een webservice-PDA-combinatie en een realtime aansturing van motoren.
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A substantial proportion of patients with burn injury develop chronic itch, which can severely affect their quality of life. As found in research on chronic pain, different psychophysiological processes may also play a role in chronic itch, of which central sensitization, conditioned modulation, and attentional processes have been studied most frequently. This study aimed to explore psychophysiological processes of chronic post-burn itch by comparing 15 patients with long-term itch due to burn injury with 15 matched healthy controls. Exploratory results indicated tendencies for higher itch sensitivity in patients than in controls, for mechanical stimuli and histamine, but not for electrical stimulation. Results further suggest that the efficacy of itch modulation by an itch- or pain-conditioning stimulus or directing attention towards itch stimuli do not differ between these patients and controls. Further elucidation of the processes underlying post-burn itch may improve the early identification and treatment of burn patients developing chronic itch.
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In this presented study, we measured in situ the uplink duty cycles of a smartphone for 5G NR and 4G LTE for a total of six use cases covering voice, video, and data applications. The duty cycles were assessed at ten positions near a 4G and 5G base-station site in Belgium. For Twitch, VoLTE, and WhatsApp, the duty cycles ranged between 4% and 22% in time, both for 4G and 5G. For 5G NR, these duty cycles resulted in a higher UL-allotted time due to time division duplexing at the 3.7 GHz frequency band. Ping showed median duty cycles of 2% for 5G NR and 50% for 4G LTE. FTP upload and iPerf resulted in duty cycles close to 100%.
MULTIFILE
The performance of a visible light communication (VLC) system based on power domain non-orthogonal multiple access (PD-NOMA) is experimentally evaluated in this paper. The simplicity of the adopted non-orthogonal scheme is provided by the fixed power allocation method at the transmitter and the single one-tap equalization executed before the successive interference cancellation at the receiver. The experimental results proved the successful transmission of the PD-NOMA scheme with three users in VLC links of up to 2.5 m, after a proper choice of the optical modulation index. All users achieved error-vector magnitude (EVM) performances below FEC limits in all evaluated transmission distances. At 2.5 m, the user with the best performance reaches an EVM = 2.3 %.
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