| 1. |
- Ebeed, Mohamed, et al.
(författare)
-
Solving stochastic optimal reactive power dispatch using an Adaptive Beluga Whale optimization considering uncertainties of renewable energy resources and the load growth
- 2024
-
Ingår i: Ain Shams Engineering Journal. - : ELSEVIER. - 2090-4479 .- 2090-4495. ; 15:7
-
Tidskriftsartikel (refereegranskat)abstract
- The electrical system performance can be improved considerably by controlling the reactive power flow in the system. The reactive power control can be achieved by optimal reactive power dispatch (ORPD) problem solution and optimal integration of the FACTS devices. With high penetration of renewable energy sources (RESs) and the load growth, the ORPD solution became a challenging and a complex task due to the stochastic nature of the RERs and the load growth. In this regard, the aim of this paper is to solve the stochastic optimal reactive power dispatch (SORPD) with optimal inclusion of PV units, wind turbines and the unified power flow controller (UPFC) under uncertainties of the load growth and the generated powers. An Adaptive Beluga Whale Optimization (ABWO) is proposed for solving the SORPD which is based on the Fitness-Distance Balance Selection (FDBS) strategy and the territorial solitary males' strategy of the Mountain Gazelle Optimizer. The proposed ABWO is tested on IEEE 30-bus system and a comparison with other optimization techniques for solving the ordinary ORPD is presented for validating the proposed ABWO. The obtained results reveal that the TEPL is reduced from 5.3168 MW to 3.97985 MW with optimal integration of the RERs and UPFC. Likewise, the TEVD is reduced from 0.1794p.u. to 0.10689p.u. and the TVSI is decreased from 0.1289p.u. to 0.0476p.u.
|
|
| 2. |
- Amin, Heba M., et al.
(författare)
-
1,2 Propanediol utilization by Lactobacillus reuteri DSM 20016, role in bioconversion of glycerol to 1,3 propanediol, 3-hydroxypropionaldehyde and 3-hydroxypropionic acid
- 2013
-
Ingår i: Journal of Genetic Engineering and Biotechnology. - : Springer Science and Business Media LLC. - 1687-157X. ; 11:1, s. 53-59
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of the presented work is to demonstrate the metabolism of 1,2 propandiol by Lactobacillus reuteri and to elucidate the metabolites produced during the process. This Metabolic pathway is crucial for biotechnological applications using L. reuteri in bioconversion of glycerol to industrially important plate-form chemicals. L. reuteri grown on minimal media containing 1,2 propanediol was able to utilize the compound as a sole carbon and energy source. The growth of the bacteria was linear with time; however the specific growth rate was significantly low compared to bacteria grown on the same media in the presence of glucose.The fermentation of 1,2 propanediol by L. reuteri in presence and absence of glucose was followed for 72 h and the metabolites produced during the process were detected using HPLC. 1,2 Propanediol was completely converted to propionaldhyde in a time dependent fashion, this process had a higher rate in presence of glucose. Consequently the produced propionaldhyde was converted to propionic acid and propanol in a skewed equimolar manner. In presence of glucose: acetic acid, lactic acid, succinic acid and ethanol were detected while in absence of glucose only minute amounts of acetic acid and lactic acid were detected which indicates presence of different metabolic pathways for glucose and 1,2 propanediol metabolism. Resting cells of L. reuteri induced in presence of 1,2 propanediol have shown significant capabilities to convert aqueous glycerol to 1,3 propanediol, 3-hydroxypropionaldhyde and a compound proposed to be 3-hydroxypropionic acid as detected by gas chromatographic technique.
|
|
| 3. |
- Khatri, C, et al.
(författare)
-
Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study
- 2021
-
Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:11, s. e050830-
-
Tidskriftsartikel (refereegranskat)abstract
- Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis.SettingProspective, international, multicentre, observational cohort study.ParticipantsPatients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative).Primary outcome30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality.ResultsThis study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p<0.001), age >80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787).ConclusionsPatients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups.Trial registration numberNCT04323644
|
|
| 4. |
- Mohamed, Sherif A. S., et al.
(författare)
-
Monocular visual odometry based on hybrid parameterization
- 2020
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE.
-
Konferensbidrag (refereegranskat)abstract
- Visual odometry (VO) is one of the most challenging techniques in computer vision for autonomous vehicle/vessels. In VO, the camera pose that also represents the robot pose in ego-motion is estimated analyzing the features and pixels extracted from the camera images. Different VO techniques mainly provide different trade-offs among the resources that are being considered for odometry, such as camera resolution, computation/communication capacity, power/energy consumption, and accuracy. In this paper, a hybrid technique is proposed for camera pose estimation by combining odometry based on triangulation using the long-term period of direct-based odometry and the short-term period of inverse depth mapping. Experimental results based on the EuRoC data set shows that the proposed technique significantly outperforms the traditional direct-based pose estimation method for Micro Aerial Vehicle (MAV), keeping its potential negative effect on performance negligible.
|
|
| 5. |
- Mohamed, Sherif A. S., et al.
(författare)
-
Towards Real-Time Edge Detection for Event Cameras Based on Lifetime and Dynamic Slicing
- 2020
-
Ingår i: Advances in intelligent systems and computing. - Cham : Springer. ; , s. 584-593
-
Konferensbidrag (refereegranskat)abstract
- Retinal cameras, such as dynamic vision sensors (DVF), transmit asynchronous events with ultra-low latency only at significant luminance changes, unlike traditional CMOS cameras which transmit the absolute brightness of all pixels including redundant backgrounds. Due to these significant characteristics, they offer great potential to obtain efficient localization of high-speed and agile platforms. Moreover, event cameras have a high dynamic range which makes them suitable for platforms that operate indoors in low-lighting scenarios and in outdoor environments, where the camera might be pointing at a strong light source, e.g. the sun. In this paper, we propose an algorithm to detect edges in event streams coming from retinal cameras. To do that, an algorithm is developed to extract edges from events by augmenting a batch of events with their lifetimes. The lifetime of each event is computed using a local plane fitting technique. We use a batching technique to increase the frame rate of generated images since events with a high sample rate cause the processing of a single event to be computationally expensive. The size of the batch will be adjusted based on the mean optical flow of the previously generated batch. The obtained experimental results show that our proposed technique can significantly reduce the response time with the same sharpness in generating the edges.
|
|
| 6. |
- Mohamed, Sherif, et al.
(författare)
-
Towards Dynamic Monocular Visual Odometry Based on an Event Camera and IMU Sensor
- 2020
-
Ingår i: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering. - Cham : Springer. ; , s. 249-263
-
Konferensbidrag (refereegranskat)abstract
- Visual odometry (VO) and visual simultaneous localization and mapping (V-SLAM) have gained a lot of attention in the field of autonomous robots due to the high amount of information per unit cost vision sensors can provide. One main problem in VO techniques is the high amount of data that a pixelated image has, affecting negatively the overall performance of such techniques. An event-based camera, as an alternative to a normal frame-based camera, is a prominent candidate to solve this problem by considering only pixel changes in consecutive events that can be observed with high time resolution. However, processing the event data that is captured by event-based cameras requires specific algorithms to extract and track features applicable for odometry. We propose a novel approach to process the data of an event-based camera and use it for odometry. It is a hybrid method that combines the abilities of event-based and frame-based cameras to reach a near-optimal solution for VO. Our approach can be split into two main contributions that are (1) using information theory and non-euclidean geometry to estimate the number of events that should be processed for efficient odometry and (2) using a normal pixelated frame to determine the location of features in an event-based camera. The obtained experimental results show that our proposed technique can significantly increase performance while keeping the accuracy of pose estimation in an acceptable range.
|
|
| 7. |
- Rosenhahn, Erik, et al.
(författare)
-
Bi-allelic loss-of-function variants in PPFIBP1 cause a neurodevelopmental disorder with microcephaly, epilepsy, and periventricular calcifications
- 2022
-
Ingår i: American Journal of Human Genetics. - : Cell Press. - 0002-9297 .- 1537-6605. ; 109:8, s. 1421-1435
-
Tidskriftsartikel (refereegranskat)abstract
- PPFIBP1 encodes for the liprin-β1 protein, which has been shown to play a role in neuronal outgrowth and synapse formation in Drosophila melanogaster. By exome and genome sequencing, we detected nine ultra-rare homozygous loss-of-function variants in 16 individuals from 12 unrelated families. The individuals presented with moderate to profound developmental delay, often refractory early-onset epilepsy, and progressive microcephaly. Further common clinical findings included muscular hyper- and hypotonia, spasticity, failure to thrive and short stature, feeding difficulties, impaired vision, and congenital heart defects. Neuroimaging revealed abnormalities of brain morphology with leukoencephalopathy, ventriculomegaly, cortical abnormalities, and intracranial periventricular calcifications as major features. In a fetus with intracranial calcifications, we identified a rare homozygous missense variant that by structural analysis was predicted to disturb the topology of the SAM domain region that is essential for protein-protein interaction. For further insight into the effects of PPFIBP1 loss of function, we performed automated behavioral phenotyping of a Caenorhabditis elegans PPFIBP1/hlb-1 knockout model, which revealed defects in spontaneous and light-induced behavior and confirmed resistance to the acetylcholinesterase inhibitor aldicarb, suggesting a defect in the neuronal presynaptic zone. In conclusion, we establish bi-allelic loss-of-function variants in PPFIBP1 as a cause of an autosomal recessive severe neurodevelopmental disorder with early-onset epilepsy, microcephaly, and periventricular calcifications.
|
|
| 8. |
- Schweinsberg, Martin, et al.
(författare)
-
Same data, different conclusions : Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis
- 2021
-
Ingår i: Organizational Behavior and Human Decision Processes. - : Elsevier BV. - 0749-5978 .- 1095-9920. ; 165, s. 228-249
-
Tidskriftsartikel (refereegranskat)abstract
- In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists' gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for orga-nizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed.
|
|
| 9. |
- Yasin, Jawad Naveed, et al.
(författare)
-
Energy-Efficient Formation Morphing for Collision Avoidance in a Swarm of Drones
- 2020
-
Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 8, s. 170681-170695
-
Tidskriftsartikel (refereegranskat)abstract
- Two important aspects in dealing with autonomous navigation of a swarm of drones are collision avoidance mechanism and formation control strategy; a possible competition between these two modes of operation may have negative implications for success and efficiency of the mission. This issue is exacerbated in the case of distributed formation control in leader-follower based swarms of drones since nodes concurrently decide and act through individual observation of neighbouring nodes' states and actions. To dynamically handle this duality of control, a plan of action for multi-priority control is required. In this paper, we propose a method for formation-collision co-awareness by adapting the thin-plate splines algorithm to minimize deformation of the swarm's formation while avoiding obstacles. Furthermore, we use a non-rigid mapping function to reduce the lag caused by such maneuvers. Simulation results show that the proposed methodology maintains the desired formation very closely in the presence of obstacles, while the response time and overall energy efficiency of the swarm is significantly improved in comparison with the existing methods where collision avoidance and formation control are only loosely coupled. Another important result of using non-rigid mapping is that the slowing down effect of obstacles on the overall speed of the swarm is significantly reduced, making our approach especially suitable for time critical missions.
|
|
| 10. |
- Yasin, Jawad N., et al.
(författare)
-
Night vision obstacle detection and avoidance based on Bio-Inspired Vision Sensors
- 2020
-
Ingår i: Proceedings 2020 IEEE SENSORS. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- Moving towards autonomy, unmanned vehicles rely heavily on state-of-the-art collision avoidance systems (CAS). However, the detection of obstacles especially during night-time is still a challenging task since the lighting conditions are not sufficient for traditional cameras to function properly. Therefore, we exploit the powerful attributes of event-based cameras to perform obstacle detection in low lighting conditions. Event cameras trigger events asynchronously at high output temporal rate with high dynamic range of up to 120 dB. The algorithm filters background activity noise and extracts objects using robust Hough transform technique. The depth of each detected object is computed by triangulating 2D features extracted utilising LC-Harris. Finally, asynchronous adaptive collision avoidance (AACA) algorithm is applied for effective avoidance. Qualitative evaluation is compared using event-camera and traditional camera.
|
|
