Decentralized Greedy-Based Algorithm for Smart Energy Management in Plug-in Electric Vehicle Energy Distribution Systems

Variations in electricity tariffs arising due to stochastic demand loads on the power grids have stimulated research in finding optimal charging/discharging scheduling solutions for electric vehicles (EVs). Most of the current EV scheduling solutions are either centralized, which suffer from low reliability and high complexity, while existing decentralized solutions do not facilitate the efficient scheduling of on-move EVs in large-scale networks considering a smart energy distribution system. Motivated by smart cities applications, we consider in this paper the optimal scheduling of EVs in a geographically large-scale smart energy distribution system where EVs have the flexibility of charging/discharging at spatially-deployed smart charging stations (CSs) operated by individual aggregators. In such a scenario, we define the social welfare maximization problem as the total profit of both supply and demand sides in the form of a mixed integer non-linear programming (MINLP) model. Due to the intractability, we then propose an online decentralized algorithm with low complexity which utilizes effective heuristics to forward each EV to the most profitable CS in a smart manner. Results of simulations on the IEEE 37 bus distribution network verify that the proposed algorithm improves the social welfare by about 30% on average with respect to an alternative scheduling strategy under the equal participation of EVs in charging and discharging operations. Considering the best-case performance where only EV profit maximization is concerned, our solution also achieves upto 20% improvement in flatting the final electricity load. Furthermore, the results reveal the existence of an optimal number of CSs and an optimal vehicle-to-grid penetration threshold for which the overall profit can be maximized. Our findings serve as guidelines for V2G system designers in smart city scenarios to plan a cost-effective strategy for large-scale EVs distributed energy management

Diagnostic accuracy of a three-protein signature in women with suspicious breast lesions: a multicenter prospective trial

Background Mammography screening has been proven to detect breast cancer at an early stage and reduce mortality; however, it has low accuracy in young women or women with dense breasts. Blood-based diagnostic tools may overcome the limitations of mammography. This study assessed the diagnostic performance of a three-protein signature in patients with suspicious breast lesions. Findings This trial (MAST; KCT0004847) was a prospective multicenter observational trial. Three-protein signature values were obtained using serum and plasma from women with suspicious lesions for breast malignancy before tumor biopsy. Additionally, blood samples from women who underwent clear or benign mammography were collected for the assays. Among 642 participants, the sensitivity, specificity, and overall accuracy values of the three-protein signature were 74.4%, 66.9%, and 70.6%, respectively, and the concordance index was 0.698 (95% CI 0.656, 0.739). The diagnostic performance was not affected by the demographic features, clinicopathologic characteristics, and co-morbidities of the participants. Conclusions The present trial showed an accuracy of 70.6% for the three-protein signature. Considering the value of blood-based biomarkers for the early detection of breast malignancies, further evaluation of this proteomic assay is warranted in larger, population-level trials. This Multi-protein Assessment using Serum to deTermine breast lesion malignancy (MAST) was registered at the Clinical Research Information Service of Korea with the identification number of KCT0004847 (https://cris.nih.go.kr).This study was supported by the Bertis Inc. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication

Few-Layer WSe₂ Schottky Junction-Based Photovoltaic Devices through Site-Selective Dual Doping

Ultrathin sheets of two-dimensional (2D) materials like transition metal dichalcogenides have attracted strong attention as components of high-performance light-harvesting devices. Here, we report the implementation of Schottky junction-based photovoltaic devices through site-selective surface doping of few-layer WSe₂ in lateral contact configuration. Specifically, whereas the drain region is covered by a strong molecular p-type dopant (NDP-9) to achieve an Ohmic contact, the source region is coated with an Al₂O₃ layer, which causes local n-type doping and correspondingly an increase of the Schottky barrier at the contact. By scanning photocurrent microscopy using green laser light, it could be confirmed that photocurent generation is restricted to the region around the source contact. The local photoinduced charge separation is associated with a photoresponsivity of up to 20 mA W^–1 and an external quantum efficiency of up to 1.3%. The demonstrated device concept should be easily transferrable to other van der Waals 2D materials

Strength and toughness of hybrid steel and glass fiber-reinforced sulfur polymer composites

In this study, we investigated the effects of microfibers on the compressive and flexural behaviors of modified sulfur composites. Dicyclopentadiene-modified sulfur was used as the binder in the sulfur composites. Fifteen mix cases were tested by varying the volumetric ratios of steel and electric chemical resistant glass fibers. Fly ash (35% by volume) was included to not only increase strength and workability, but also ensure fiber dispersibility in the matrix. A non-contact displacement measurement technique, digital image correlation, was used in flexure tests to monitor the development of high strain zones and microcracks. The effect of fiber dosage on the porosity of sulfur composites was analyzed by quantifying the pore volume and size distribution through mercury intrusion porosimetry. The test results confirmed that the hybrid use of steel and glass fibers with a volume ratio of up to 4% was effective in improving the flexural stress-deflection response. The post-peak toughness ratio in flexure increased as the volume of microfibers increased. In addition, the total volume of hybrid microfibers generally had a positive correlation with the flexural strength. In contrast, the compressive strength of hybrid fiber-reinforced sulfur composites was more dependent on the portion of steel fibers than glass fibers