Loss Of Branches Research Articles

SPMUNet: Semantic segmentation of citrus surface defects driven by superpixel feature

The segmentation of surface defects in citrus fruit makes a significant contribution to quality assessment and post-harvest processing. However, semantic segmentation of citrus surface defects remains challenging owing to the complexity of defect features, unclear defect boundaries and semantic gaps in models. Therefore, a superpixel driven and multiscale channel cross-fusion transformer (MCCT)-based UNet (named SPMUNet) was proposed to segment citrus surface defects. The model first created a multiscale superpixel region feature (MSRF) branch using the simple linear iterative cluster (SLIC) algorithm to form the key features embedded in the downsampling layer. Then, the proposed Superpixel Loss optimized the loss function based on superpixel grid to provide error information for boundary segmentation. In addition, the MCCT module was used to improve the skip connection layers, and feature fusion was achieved by collaborative learning. Finally, the performance of the model was validated through ablation studies, feature map visualization, and comparison experiments. The results showed that the mPA, mIoU, and dice coefficients of SPMUNet for citrus surface segmentation were 89.1%, 83.8%, and 88.6%, respectively. Compared with the baseline, the proposed MSRF branch, MCCT, and Superpixel Loss improved mIoU by 2.6%, 1.3%, and 4.2%, respectively. And the effectiveness of the proposed methods was also validated by the feature map visualization. Furthermore, the proposed SPMUNet achieved optimal segmentation performance compared to other semantic segmentation models (UNet, ResUNet++, DeepLabv3+, SwinUNet, TransUNet). SPMUNet also excelled in the segmentation of small targets and boundaries, improving by 10.2% and 7.0%, respectively, over the baseline. The improvement in segmentation performance demonstrated the effectiveness of the selected superpixel features. The proposed citrus surface defect segmentation model achieved high-precision segmentation and serves as a technical reference for citrus sorting and quality assessment.

BIFURCATION: A CLINICAL CASE IN ACUTE CORONARY SYNDROME

Abstract Bifurcation A clinical case in acute coronary syndrome. Coronary bifurcation lesions are considered one of challenging entities in the field of coronary intervention due to the risk of side branch loss and higher risk of stent thrombosis. There are limited data on the preferred treatment strategy in ST–segment elevation myocardial infarction (STEMI) patients with bifurcation lesions as most dedicated study excluded patients with acute coronary syndrome. In all comers population a 10–20% of STEMI patients had bifurcation culprit lesion. In 2018 guideline suggested a provisional approach by stenting the main vessel and implanting a second stent only if necessary as a bailout strategy. This reccomandation was supported by a large series of study that uniquely documented the superiority of one versus two stent technique. The same message could also be exported in the context of acute patients, as our clinical case, thanks to registry like COBIS 2 including ST–segment elevation patient. But this precious advice cannot be applied in all clinical subsets. Especially when we manage with a relevant side–branch and when the risk of loosing the side branch is very high. In this subgroup of patient, bifurcation lesion may benefit from a 2 stent approach. Different technical option are available. Among these, DK–crush and inverted Main Branch stenting across Side Branch (Invertend Culotte or inverted T technique) could be the best choice. Our patient was a young lady presenting with a lateral STEMI (D1 and aVL). The culprit lesion was a Medina 1.1.1 bifurcation lesion involving left anterior descending and first–diagonal. Since our side branch had thrombus inside, the vessel was relevant by definition. Other anatomical characteristique to take into account: relevant size and covering a large myocardial territory. Planning the strategy to treat our LAD–D1 bifurcation we consider the angle and the difference in size between main and side branch. We decided to proceed with DK–crush and its recent evolution DK–nano crush. In conclusion “do it provisional” guideline message is not always possible, 2 stent technique seems to be the best choice in presence of a relevant side–branch / high risk to loose it. Our take home message is, if the clinical scenario allow it, don’t hesitate to perform a multistep two vessel strategy technique and to try to reconstruct perfect anatomical carina even in STEMI context.

Modeling and analysis method for carbon emission flow in integrated energy systems considering energy quality

AbstractWhile proposing dual carbon strategy goals, research on carbon reduction in integrated energy systems (IESs) has become a focus of attention. Traditional IES carbon emission flow is mostly based on energy flow, without considering the differences in energy quality. Exergy can be used as a reasonable measure of energy quality. Combining the theory of exergy flow and carbon emission flow, a modeling and analysis method for IES carbon emission flow considering energy quality is proposed. First, exergy flow models for electric and natural gas systems, equivalent exergy flow models for heat systems, and exergy hub models are introduced. Afterward, the exergy branch losses are allocated to the nodes at both ends. A networked modeling method for the carbon emission flow of energy stations is proposed. A unified matrix calculation model for IES carbon emission flow considering energy quality is established. On this basis, an IES carbon emission flow calculation method considering energy quality is proposed. Finally, this method is applied to the test IES, and the results show that the carbon emission flow calculation results reflect the distribution of carbon emissions borne by the effective energy supplied by the source and consumed by the load in the system, taking into account both the quantity and quality of energy. The reasonable allocation of new energy is conducive to synchronously improving the energy efficiency, exergy efficiency, and cleanliness of the system.

Alternate routes to mnm5s2U synthesis in Gram-positive bacteria.

The wobble bases of tRNAs that decode split codons are often heavily modified. In bacteria, tRNAGlu, Gln, Asp contains a variety of xnm5s2U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm5s2U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the conversion of cmnm5s2U to mnm5s2U. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the radical Sam superfamily was found to be involved in the synthesis of mnm5s2U in both Bacillus subtilis and Streptococcus mutans. This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm5s2U into mnm5s2U in B. subtilis. Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathway intermediates owing to regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. Although mechanistic details of these newly discovered components are not fully resolved, the occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in Nature.IMPORTANCEThe xnm5s2U modifications found in several tRNAs at the wobble base position are widespread in bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile radical SAM superfamily and is involved in the synthesis of mnm5s2U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications.

Acute and Chronic Oak Decline in urban and forest ecosystems in Southern Italy

Abstract Since recently, a decline of holm oak (Quercus ilex L.) is observed in Salento (South Italy), this caused concern regarding the protection of native biodiversity and local forests. Symptomatic trees show browning of leaves, thinning of canopy, and loss of branches. The aim of this study was to understand the biotic factors involved in the observed decline. During the monitoring activity, the use of phenotypic descriptors highlighted the presence of two types of decline with distinct symptoms among oaks in rural and urban areas, which could be classified as Acute Oak Decline (AOD) and Chronic Oak Decline (COD), respectively. Following this, diagnostic analyses were carried out to assess the presence of various holm oak pathogens on twigs, trunk, and soil. These analyses revealed the presence of several Botryosphaeriaceae oak pathogens, present ubiquitously between the two environmental contexts, with Diplodia seriata being overall the most prevalent. Contrarily, bacteria associated with AOD were only present in the rural areas and included: Brenneria goodwinii, Gibbsiella quercinecans, and Rahnella victoriana. As far as known to the authors, this is the first time these pathogens have been found in the Mediterranean coastal regions. Lastly, soil analyses performed to detect the presence of Phytophthora cinnamomi were negative. Our results highlight the presence of several pathogens, which indicates that oak decline is a multifactorial phenomenon for which the predisposing, initial, and contributing factors are not yet known particularly for the recently described AOD and COD. Finally, the identification of AOD-related bacteria in Salento is a cause of concern for the need of urgent management actions aimed to contain their spread and to preserve the forest heritage of the region.

Predicting resprouting of Platanus × hispanica following branch pruning by means of machine learning.

Resprouting is a crucial survival strategy following the loss of branches, being it by natural events or artificially by pruning. The resprouting prediction on a physiological basis is a highly complex approach. However, trained gardeners try to predict a tree's resprouting after pruning purely based on their empirical knowledge. In this study, we explore how far such predictions can also be made by machine learning. Table-topped annually pruned Platanus × hispanica trees at a nursery were LiDAR-scanned for two consecutive years. Topological structures for these trees were abstracted by cylinder fitting. Then, new shoots and trimmed branches were labelled on corresponding cylinders. Binary and multiclass classification models were tested for predicting the location and number of new sprouts. The accuracy for predicting whether having or not new shoots on each cylinder reaches 90.8% with the LGBMClassifier, the balanced accuracy is 80.3%. The accuracy for predicting the exact numbers of new shoots with the GaussianNB model is 82.1%, but its balanced accuracy is reduced to 42.9%. The results were validated with a separate dataset, proving the feasibility of resprouting prediction after pruning using this approach. Different tree species, tree forms, and other variables should be addressed in further research.

Formation mechanism of α particles in glycogen: Testing the budding hypothesis by Monte-Carlo simulation

Glycogen, a complex branched glucose polymer and a blood-sugar reservoir in animals, comprises small β particles joined together into composite α particles. In diabetic animals, α particles fragment more easily than those in healthy animals. Finding evidence for or against postulated mechanisms for α-particle formation is thus important for diabetes research. Insight into this is obtained here using Monte-Carlo simulations, including addition and loss of glucose monomer, branching and debranching, based on earlier simulations which were in acceptable agreement with experiment [Zhang et al., Int J Biol Macromolecules 2018, 116, 264]. One postulated mechanism for α-particle formation is “budding”: occasionally a glucan chain temporarily protrudes from the particle, and if its growing end is sufficiently far from its parent particle, it propagates to a new linked particle. We tested this by simulations in which an “artificial” bud (a chain extending well outside the average particle radius) is added to a glycogen molecule in a dynamic steady state, and the system allowed to evolve. In some simulations, the particle reached a new steady state having an irregular dumbbell shape: a rudimentary α particle. Thus ‘budding’ is a possible mechanism for α particles to form. If no simulations had shown this behaviour, it would have refuted the postulate.

Potent in vivo efficacy of oral gallium maltolate in treatment-resistant glioblastoma.

Treatment-resistant glioblastoma (trGBM) is an aggressive brain tumor with a dismal prognosis, underscoring the need for better treatment options. Emerging data indicate that trGBM iron metabolism is an attractive therapeutic target. The novel iron mimetic, gallium maltolate (GaM), inhibits mitochondrial function via iron-dependent and -independent pathways. In vitro irradiated adult GBM U-87 MG cells were tested for cell viability and allowed to reach confluence prior to stereotactic implantation into the right striatum of male and female athymic rats. Advanced MRI at 9.4T was carried out weekly starting two weeks after implantation. Daily oral GaM (50mg/kg) or vehicle were provided on tumor confirmation. Longitudinal MRI parameters were processed for enhancing tumor ROIs in OsiriX 8.5.1 (lite) with Imaging Biometrics Software (Imaging Biometrics LLC). Statistical analyses included Cox proportional hazards regression models, Kaplan-Meier survival plots, linear mixed model comparisons, and t-statistic for slopes comparison as indicator of tumor growth rate. In this study we demonstrate non-invasively, using longitudinal MRI surveillance, the potent antineoplastic effects of GaM in a novel rat xenograft model of trGBM, as evidenced by extended suppression of tumor growth (23.56 mm3/week untreated, 5.76 mm3/week treated, P < 0.001), a blunting of tumor perfusion, and a significant survival benefit (median overall survival: 30 days untreated, 56 days treated; P < 0.001). The therapeutic effect was confirmed histologically by the presence of abundant cytotoxic cellular swelling, a significant reduction in proliferation markers (P < 0.01), and vessel normalization characterized by prominent vessel pruning, loss of branching, and uniformity of vessel lumina. Xenograft tumors in the treatment group were further characterized by an absence of an invasive edge and a significant reduction in both, MIB-1% and mitotic index (P < 0.01 each). Transferrin receptor and ferroportin expression in GaM-treated tumors illustrated cellular iron deprivation. Additionally, treatment with GaM decreased the expression of pro-angiogenic markers (von Willebrand Factor and VEGF) and increased the expression of anti-angiogenic markers, such as Angiopoietin-2. Monotherapy with the iron-mimetic GaM profoundly inhibits trGBM growth and significantly extends disease-specific survival in vivo.

Design of Dynamic Voltage Restorer for Power Quality Improvement

Solutions for customers with delicate loads and quick voltage regulation are essential. Protect important loads from supply-side voltage disturbances with a power electronic converter-based Dynamic Voltage Restorer (DVR). In the case of severe sag and swell, DVR is a well-known, low-cost therapy option. On the basis of its maximum voltage injection and active power contribution, a DVR's mitigation ability is determined. Standard DVRs use batteries as their DC input, but batteries are cumbersome, expensive, and hazardous to dispose of after they've been used. This limits compensation for DVRs. It is recommended to increase the DVR's VA rating by 1.5 times by increasing the DC connection voltage to 1.5 times the micro grid voltage regulation and quality improvement methods are proposed in this study. As a series voltage compensator, these solutions incorporate a Dynamic Voltage Restorer (DVR) for regulation, quality improvement, and reduction of harmonic distortion. Continuous adjustment of the DVR output voltage is proposed to reduce harmonic distortions while minimizing network bus voltage changes. As a result of this strategy, the peak demand voltage loss is compensated for. In constant impedance loads, voltage rise reduces network demand, resulting in lower branch currents and losses

MSVTNet: Multi-Scale Vision Transformer Neural Network for EEG-Based Motor Imagery Decoding.

Transformer-based neural networks have been applied to the electroencephalography (EEG) decoding for motor imagery (MI). However, most networks focus on applying the self-attention mechanism to extract global temporal information, while the cross-frequency coupling features between different frequencies have been neglected. Additionally, effectively integrating different neural networks poses challenges for the advanced design of decoding algorithms. This study proposes a novel end-to-end Multi-Scale Vision Transformer Neural Network (MSVTNet) for MI-EEG classification. MSVTNet first extracts local spatio-temporal features at different filtered scales through convolutional neural networks (CNNs). Then, these features are concatenated along the feature dimension to form local multi-scale spatio-temporal feature tokens. Finally, Transformers are utilized to capture cross-scale interaction information and global temporal correlations, providing more distinguishable feature embeddings for classification. Moreover, auxiliary branch loss is leveraged for intermediate supervision to ensure the effective integration of CNNs and Transformers. The performance of MSVTNet was assessed through subject-dependent (session-dependent and session-independent) and subject-independent experiments on three MI datasets, i.e., the BCI competition IV 2a, 2b and OpenBMI datasets. The experimental results demonstrate that MSVTNet achieves state-of-the-art performance in all analyses. MSVTNet shows superiority and robustness in enhancing MI decoding performance. The source code for MSVTNet is available at https://github.com/SheepTAO/MSVTNet.

The laser‐cooling of low‐lying states of gold‐aluminum MRCI+Q study including spin‐orbit coupling

AbstractThe possible laser cooling of AuAl molecules was investigated using high‐level ab initio calculations and considering the spin‐orbit coupling effect. Multi‐reference configuration interaction and the Davidson correction were also employed. Six Λ‐S electronic states were obtained, which were divided into 14 Ω states via spin‐orbit coupling. The optical transition showed potential for laser‐cooling applications owing to its highly diagonal Franck‐Condon factors and larger vibrational branching ratios. A possible optical cycling scheme using four lasers at near‐resonance wavelengths to eliminate vibrational branching loss is proposed. This scheme can be experimentally tested in future laser‐cooling experiments.

Neuronal dysfunction caused by FUSR521G promotes ALS-associated phenotypes that are attenuated by NF-κB inhibition

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are related neurodegenerative diseases that belong to a common disease spectrum based on overlapping clinical, pathological and genetic evidence. Early pathological changes to the morphology and synapses of affected neuron populations in ALS/FTD suggest a common underlying mechanism of disease that requires further investigation. Fused in sarcoma (FUS) is a DNA/RNA-binding protein with known genetic and pathological links to ALS/FTD. Expression of ALS-linked FUS mutants in mice causes cognitive and motor defects, which correlate with loss of motor neuron dendritic branching and synapses, in addition to other pathological features of ALS/FTD. The role of ALS-linked FUS mutants in causing ALS/FTD-associated disease phenotypes is well established, but there are significant gaps in our understanding of the cell-autonomous role of FUS in promoting structural changes to motor neurons, and how these changes relate to disease progression. Here we generated a neuron-specific FUS-transgenic mouse model expressing the ALS-linked human FUSR521G variant, hFUSR521G/Syn1, to investigate the cell-autonomous role of FUSR521G in causing loss of dendritic branching and synapses of motor neurons, and to understand how these changes relate to ALS-associated phenotypes. Longitudinal analysis of mice revealed that cognitive impairments in juvenile hFUSR521G/Syn1 mice coincide with reduced dendritic branching of cortical motor neurons in the absence of motor impairments or changes in the neuromorphology of spinal motor neurons. Motor impairments and dendritic attrition of spinal motor neurons developed later in aged hFUSR521G/Syn1 mice, along with FUS cytoplasmic mislocalisation, mitochondrial abnormalities and glial activation. Neuroinflammation promotes neuronal dysfunction and drives disease progression in ALS/FTD. The therapeutic effects of inhibiting the pro-inflammatory nuclear factor kappa B (NF-κB) pathway with an analog of Withaferin A, IMS-088, were assessed in symptomatic hFUSR521G/Syn1 mice and were found to improve cognitive and motor function, increase dendritic branches and synapses of motor neurons, and attenuate other ALS/FTD-associated pathological features. Treatment of primary cortical neurons expressing FUSR521G with IMS-088 promoted the restoration of dendritic mitochondrial numbers and mitochondrial activity to wild-type levels, suggesting that inhibition of NF-κB permits the restoration of mitochondrial stasis in our models. Collectively, this work demonstrates that FUSR521G has a cell-autonomous role in causing early pathological changes to dendritic and synaptic structures of motor neurons, and that these changes precede motor defects and other well-known pathological features of ALS/FTD. Finally, these findings provide further support that modulation of the NF-κB pathway in ALS/FTD is an important therapeutic approach to attenuate disease.

Seasonal Susceptibility of Sweet Cherry Pruning Wounds to Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata.

Fungal canker pathogens commonly infect trees at pruning wounds leading to branch dieback and loss of productivity in sweet cherry orchards. However, the seasonal susceptibility of sweet cherry pruning wounds to Calosphaeria pulchella, Cytospora sorbicola, and Eutypa lata is not well understood. This study compared the susceptibility of sweet cherry pruning wounds made during the dormant season (January) and the postharvest season (late May to June) to infection by main canker pathogens in California. Field trials were conducted in three cherry orchards and trees were pruned at the different periods over 2 years. Fresh pruning wounds were inoculated with spores of each pathogen, and pathogen recovery was assessed through microbiological isolations at 3 to 4 months after inoculations. Pruning wounds made in late May and June resulted in significantly higher infection by Cal. pulchella compared to pruning wounds made in January. Pruning wounds made during both seasons were generally equally susceptible to Cyt. sorbicola and E. lata infections. However, there was one orchard where dormant pruning wounds were more susceptible to infection by E. lata and there was one particularly cold winter where Cyt. sorbicola did not infect pruning wounds. Overall, our findings suggest that Cal. pulchella infections of cherry pruning wounds are more likely to occur during periods of warm temperatures such as late spring and early summer. However, infections by Cyt. sorbicola and E. lata can occur year-round if inoculum is present and if winter temperatures are not abnormally low for California. Finally, our results suggest that the emergence of Cal. pulchella as a major canker pathogen of sweet cherry in California may be the result of a shift from dormant to after-harvest pruning of sweet cherry trees.

Banking for the Other Half: The Factors That Explain Banking Desert Formation

Banks are one of the key drivers of economic development across communities. Banking deserts—defined by inadequate banking access—limit access to capital, inhibit wealth accumulation, and increase exposure to predatory lending. Banking desert formation could be profit-driven, with lower-income and less densely populated regions more likely to become banking deserts. Discrimination could also play a role here: banks may have less presence in areas with higher minority populations. The authors use a panel, census tract-level data set for the entire state of North Carolina to investigate how these forces impact banking access and banking desert formation. Panel methodologies are incorporated to investigate the extent to which profit and discrimination mechanisms each drive banking access and banking desert formation. Profit and discrimination mechanisms are shown to play roles, highlighting the need for policies that mitigate bank branch losses in underserved neighborhoods.

Analysis of Radial Distribution Systems by using Particle Swarm Optimization under Uncertain Conditions

Abstract: Losses in the network are one of the most important parts of a power distribution network, and work should be done to lower their value. The research used the Particle Swarm Optimisation (PSO) metaheuristic algorithm to investigate the impact of concurrently optimising phase balance and conductor size on the planning issues and objective functions of an imbalanced distribution system. These objective functions include power loss, voltage unbalance, total neutral current, and complicated power unbalance. Firstly, the optimisation process is applied to each goal function. Then, they are put together with weights to form a multi-objective optimisation problem. In this study, it was tried to find out how to minimise losses in electrical power distribution networks that aren't fair. Power flow and optimal DG placement are two PSO techniques that may be used to reduce losses. These changes may be applied to existing distribution systems using an effective load-flow method for a three-phase imbalanced radial distribution network. Knowing the node voltage, angle, branch current, actual power loss, wattles power loss, branch losses, etc. helps determine the network's true state. Simple formulae may be used to describe the relationship between the voltage at one end of the distribution system, the voltage at the other end, and the voltage drops throughout the whole system. An approach is developed to identify the relevant variables. The voltage's angle at the target is calculated with its magnitude. It's a process that requires time and effort. From the substation to each terminal node, the constant voltage of 1p.u. is considered. Voltage magnitude and phase angle are varied between repetitions, and voltage reductions are computed using the new parameters. The suggested approach has been applied to 19- and 25-node networks with unequal distribution. To demonstrate its efficacy, the recommended approach's speed requirements were compared to those of another recently developed technology. Good outcomes are achieved, and DG proves to be a viable option for reducing costs and improving performance.

Experiência inicial com a extensão de cateter-guia ExpressmanTM em um centro terciário de cardiologia de alto volume

Background: Guide catheter extensions provide increased support in complex percutaneous coronary interventions. The ExpressmanTM is a novel guide catheter extension and the objective was to assess the impact of its use on procedural success and complications in a high-volume reference center. Methods: We analyzed data from all consecutive procedures in which the ExpressmanTM guide catheter extension was used. The decision to use a guide catheter extension was at operator’s discretion. Device success was defined as the successful positioning of the guide catheter extension in the coronary vessel and procedural success was defined as &lt;20% residual stenosis and TIMI 3 flow, with no loss of significant side branches. Major adverse cardiac and cerebrovascular events were defined as the composite of all-cause death, myocardial infarction, target vessel revascularization and stroke. Results: From April 2022 to January 2023, 34 procedures were included. The majority of the patients were male (59%) and the mean age was 66.5 years. Guide catheter extension use was not planned pre-procedure in 17 procedures (50%). The most common reasons for guide catheter extension use were target vessel angulation or tortuosity and unfavorable coronary ostium position. Device success was obtained in 88% and revascularization success in 91%. There were three side branch occlusions. During in-hospital clinical follow-up, no major adverse cardiac and cerebrovascular events or major bleeding occurred. Conclusion: The device success and procedural success were high and the rate of complications was low. Guide catheter extension use as bailout technique in complex anatomies allowed procedural success in the vast majority of otherwise untreatable patients.

Consider Carbon Emission Flow Analysis of Power System with Regards to Power Loss and Wind Power Uncertainty

A method for analyzing the impact of wind power uncertainty and active power loss on carbon emission flow in power systems is proposed. Based on the stochastic power flow calculation of wind power injection, the correlation function between wind power output and the total carbon injection rate into the system is determined. Meanwhile, the reverse power flow method is used to analyze the contribution of each unit to the active power flow in different parts of the system and calculate the corresponding carbon emissions. Under the assumption that wind power fluctuations are borne by balancing units, this method combines a conventional unit and a system node, branch, load, and active network loss correlation matrix calculation model to solve the average impact factor of wind power injection on other nodes and branches, thereby determining the uncertain characteristics of carbon emission flow in power systems under stochastic and intermittent wind power injection. The correctness and effectiveness of the method are proved by analyzing the IEEE 14-node standard example, providing new theoretical support and ideas for quantitatively evaluating the low-carbon contribution of wind power generation to the system.

A Novel Bus-Ranking-Algorithm-Based Heuristic Optimization Scheme for PMU Placement

This article presents a scheme for cost-optimized phasor measurement unit (PMU) placement and associated communication infrastructure (CI) design. For this purpose, a bus ranking algorithm is proposed, which ranks the buses in terms of connectivity, associated branch lengths, and supplementary network coverage ability that incentivizes better redundancy and lesser CI requirement. Next, a genetic algorithm (GA) is employed to search for minimum-cost optimal PMU placement solutions within the search space defined by the ranked-bus order. The search space is expanded by adding buses in the ranked order till GA finds a suitable solution satisfying the requisite constraints. The proposed scheme's performance is validated through comparison with existing state-of-the-art algorithms for IEEE 14-, 30-, and 118-bus networks under normal, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N-1$</tex-math></inline-formula> PMU contingency, branch loss contingency, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$N-1$</tex-math></inline-formula> PMU/branch loss contingency conditions. In addition, considering real-world applications, the performance of the proposed scheme under channel-limit conditions is reported in this article.

A novel estimation method for maximum PV hosting capacity in radial distribution networks using bus voltage and electrical distance

Large-scale photovoltaics (PV) generation at the distribution network causes overvoltage problems. These large PV systems are generally connected to the distribution network in three-phase configurations to ensure that power is balanced across all phases. At the same time, radial distribution networks are a common configuration of power systems worldwide as it is simpler and more cost-effective than meshed networks. In such a context, this paper proposes a novel method to estimate PV hosting capacity (PHC) for connection points in a radial and three-phase balanced distribution network. Different from existing methods that normally require power flow solutions of the network, the proposed method only needs line parameters and the historical voltage at the connection point. In addition, the proposed method features conservative estimation for PHC and thus can ensure the safety of network voltage compared with existing methods. The accuracy is tested on the IEEE 33 bus system and the estimation error is within 6%. Furthermore, the proposed method can be easily extended to consider branch losses that can reduce the estimation error to be within 1%. The obtained results have confirmed the feasibility and effectiveness of the proposed method.

A fast linearized AC power flow-constrained robust unit commitment approach with customized redundant constraint identification method

The large-scale integration of renewable energy resources in the power system challenges its economic and secure operation. Particularly, the increasing penetration of renewable energy will result in insufficient system voltage regulation and reactive power support capabilities, and may cause high risks of nodal voltage and branch flow violations. Therefore, to hedge the operational risks under the worst realization of uncertainties of renewable energy sources, a two-stage robust unit commitment (UC) model is developed. Meanwhile, the convexified AC power flow model is incorporated in the robust UC model to more accurately characterize the real-time operating status of power systems. On this basis, an AC power flow-constrained robust unit commitment (ACRUC) model is formulated. A circular linearization method is then adopted to handle the quadratic constraints in the original AC power flow model, transforming them into tractable linear constraints. Furthermore, to reduce the computational complexity caused by the large-scale newly-added constraints after the linearization process, a customized redundant constraint identification (RCI) method is developed, in which two different modes (i.e., cold and warm start modes) are designed considering the difference in base case system operating condition for linearizing branch losses. Then, the redundant network security constraints could be identified by solving a series of relatively simple optimization subproblems. Numerical results on the modified NERL-118 test system indicate that the proposed model could accurately depict actual operation and scheduling conditions, and also verify that the proposed customized RCI method could effectively reduce the problem scale and improve the solution efficiency.