Wireless sensor networks can be used to monitor targets continuously. This assumes sensor nodes have energy neutral operation, whereby the energy consumed to monitor targets is less than their ...harvested energy. In this paper, we consider a new problem: minimum energy harvesting node placement for energy neutral coverage and connectivity (MEHNP-ENCC). We aim to determine the locations to place the minimal number of nodes used for sensing and relaying such that deployed nodes 1) cover all targets, 2) have a path to the sink, and 3) have energy neutral operation. We first model MEHNP-ENCC as a mixed integer linear program (MILP). After that we propose an MILP-based approach called greedy MILP (GMILP), whereby a greedy heuristic is used to generate a collection of locations. We also propose two heuristics: 1) DirectSearch considers locations that cover one or more lines connecting targets to the sink, whilst 2) GreedySearch also considers locations farther afield from the said lines that have a high recharging rate. Simulation results show that DirectSearch requires 20% more sensor nodes than the optimal solution whilst this value is 10% for GreedySearch and GMILP.
Redactable Blockchain aims to ensure the immutability of the data of most applications and provide authorized mutability for some specific applications, such as for removing illegal content from ...blockchains. However, the existing Redactable Blockchains lack redacting efficiency and protection of the identity information of voters participating in the redacting consensus. To fill this gap, this paper presents an anonymous and efficient redactable blockchain scheme based on Proof-of-Work (PoW) in the permissionless setting, called "AeRChain". Specifically, the paper first presents an improved Back's Linkable Spontaneous Anonymous Group (bLSAG) signatures scheme and uses the improved scheme to hide the identity of blockchain voters. Then, in order to accelerate the achievement of redacting consensus, it introduces a moderate puzzle with variable target values for selecting voters and a voting weight function for assigning different weights to puzzles with different target values. The experimental results show that the present scheme can achieve efficient anonymous redacting consensus with low overhead and reduce communication traffic.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper addresses the problem of maximizing the network lifetime of rechargeable Wireless Sensor Networks (WSNs) whilst ensuring all targets are monitored continuously by at least one sensor node. ...The objective is to determine a group of sensor nodes, and their wake-up schedule such that within a time interval, one subset of nodes are active whilst others enter the sleep state to conserve energy as well as recharge their battery. We propose a Linear Programming (LP) based solution to determine the activation schedule of sensor nodes whilst affording them recharging opportunities and at the same time ensures complete target coverage. The results show our LP solution achieves more than twice the performance in terms of network lifetime as compared to similar algorithms developed for finite battery WSNs. However, it is computationally expensive. We therefore propose Maximum Utility Algorithm (MUA), a few orders of magnitude faster approach that achieves 3/4 of the network lifetime obtained by our LP solution.
This paper considers a resource allocation problem involving servers and mobile users (MUs) operating in a serverless edge computing (SEC)-enabled Internet of Things (IoT) network. Each MU has a ...fixed budget, and each server is powered by the grid and has energy harvesting (EH) capability. Our objective is to maximize the revenue of the operator that operates the said servers and the number of resources purchased by the MUs. We propose a Stackelberg game approach, where servers and MUs act as leaders and followers, respectively. We prove the existence of a Stackelberg game equilibrium and develop an iterative algorithm to determine the final game equilibrium price. Simulation results show that the proposed scheme is efficient in terms of the SEC’s profit and MU’s demand. Moreover, both MUs and SECs gain benefits from renewable energy.
•Ultra-fine grain size (less than 1 μm) can be achieved in the Mg–Ca dilute alloy.•Yield strength of ∼290 MPa in the Mg–0.1 wt% Ca alloy can be achieved.•Excellent combined mechanical properties have ...been achieved.•Formation mechanism of ultra-fine grain size is clarified.
We reported that the Mg–Ca dilute alloys can exhibit ultra-fine grain size (less than 1 μm) and the exceptionally high yield strength, e.g., ∼290 MPa in the Mg–0.1 wt% Ca alloy and ∼377 MPa in Mg–1.0 wt% Ca alloy, achieved by conventional one-step extrusion. Both increased activations of non-basal slips due to Ca addition and the dynamic partitioning of Ca atoms during extrusion are believed to play the critical role in facilitating formation of the submicron matrix grains. Multi-scale substructures, including the ultrafine recrystallized grains, the mono-dispersive Mg2Ca nano-phases, residual dislocations and Ca enriched sub-grain boundaries contribute to the high strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although centrality is widely used to differentiate the importance of nodes for social-aware routing in mobile opportunistic networks (MONs), it is destination-agnostic since such metrics are usually ...measured without destination information. To this end, we propose a destination-aware social routing scheme for MONs, namely DAS, which utilizes the destination-aware betweenness centrality (DBC) to choose the right nodes as relays given the specific destination node. During the process of message dissemination, the number of replicas for a message is calculated by the source and each relay independently in respond to the network condition in a dynamic manner. Therefore, DAS disseminates only a few message copies to ensure data delivery as well as reducing routing cost. We conduct extensive simulations using real trace data sets to show improved performance with low overhead in comparison with existing social-aware routing approaches in various scenarios.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Metabolic reprogramming has been described in rapidly growing tumors, which are thought to mostly contain fast‐cycling cells (FCCs) that have impaired mitochondrial function and rely on aerobic ...glycolysis. Here, we characterize the metabolic landscape of glioblastoma (GBM) and explore metabolic specificities as targetable vulnerabilities. Our studies highlight the metabolic heterogeneity in GBM, in which FCCs harness aerobic glycolysis, and slow‐cycling cells (SCCs) preferentially utilize mitochondrial oxidative phosphorylation for their functions. SCCs display enhanced invasion and chemoresistance, suggesting their important role in tumor recurrence. SCCs also demonstrate increased lipid contents that are specifically metabolized under glucose‐deprived conditions. Fatty acid transport in SCCs is targetable by pharmacological inhibition or genomic deletion of FABP7, both of which sensitize SCCs to metabolic stress. Furthermore, FABP7 inhibition, whether alone or in combination with glycolysis inhibition, leads to overall increased survival. Our studies reveal the existence of GBM cell subpopulations with distinct metabolic requirements and suggest that FABP7 is central to lipid metabolism in SCCs and that targeting FABP7‐related metabolic pathways is a viable therapeutic strategy.
Synopsis
Transcriptomic and metabolomic profiling of primary brain tumor cells demonstrate that functionally different glioblastoma (GBM) cell subpopulations depend on distinct metabolic pathways for their growth and survival. More invasive slow cycling tumor cells rely on oxidative phosphorylation and lipid metabolism, suggesting targetable candidates for the inhibition of treatment‐resistant tumors.
Patient‐derived GBM cells contain fast‐cycling cells (FCCs) relying on aerobic glycolysis and slow‐cycling cells (SCCs) depending on mitochondrial oxidative phosphorylation in vivo.
SCCs show increased resistance, invasion, and metabolic gene signatures characteristic of recurrent tumors.
SCCs show increased levels of metabolites and components involved in lipid metabolism, storage, and transport.
Block of FABP7‐dependent exogenous fatty acid uptake decreases resistance of SCCs to chemotherapy and glucose deprivation.
Oxidative phosphorylation and lipid metabolism specify distinct energetic set‐up of invasive brain tumor cells.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Effect of different rolling reductions on the microstructure and mechanical properties of Mg-6Al-3Zn-0.1Mn wt.% alloys were investigated by means of scanning electron microscopy (SEM), electron ...backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The results show that after rolling the as-extruded Mg-Al-Zn-Mn alloy, more second phases are dynamically precipitated. The grains are also gradually refined with increasing the total reduction due to the dynamic recrystallization, and the average grain sizes are estimated to be ∼7.2 μm, ∼3.7 μm, ∼1.2 μm for the as-extruded Mg alloy, ∼34% and ∼60% rolled samples, respectively. On the other hand, the high-density contraction twins have been activated in as-rolled Mg samples, which can effectively separate the Mg matrix and a similar grain refinement effect can be afforded. Moreover, the dislocations are significantly multiplied during the rolling process. Consequently, the tensile strength of the Mg alloy is gradually increased, and the ∼60% rolled Mg alloy exhibits the optimal mechanical properties, with the ultimate tensile strength (UTS) of ∼363 MPa and the elongation of ∼7.2%.
•Ultra-fined grain size of ∼1.2 μm was produced in AZM630 alloy by combining extrusion and rolling.•The tensile yield strength of as-rolled Mg alloy is up to 327 MPa with high elongation of 7.2%.•Dislocation tangles and contraction twin boundaries effectively improved both the strength and ductility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The deformation behavior of the mush zone for superalloy during investment casting directly affects the dimensional control of casting has puzzled many engineers and scientists for years. Numerical ...simulations are not directly useful to predict the most suitable pattern allowances. A new data-driven approach to be effectively used for pattern allowance and casting process parameters prediction is proposed. The constitutive relationships and deformation parameter from high-temperature mechanical tests on superalloy K4169 is reported. The inputs are alloy temperature, shell temperature, and pattern allowance with the outputs of diameter and ovality of the ring-to-ring casting, respectively. It turns out that the shell temperature is the most momentous factor that governs the dimensional variability in ovality. An RBF-based approximation model is established and the optimized parameters are the alloy temperature 1500.5°C, shell temperature1052.5°C, and the pattern allowance 1.7258%. The optimized results agree well with the observed in practical casting and the ring-to-ring casting tolerance has been optimized as required within CT6 grade. The proposed method is believed to benefit to provide theoretical guidance for casting practice. The data-driven approach used in this research can be easily applied to different materials and different kinds of casting that are subject to dimensional control upon solidification.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This work reported the effect of extrusion speeds on the microstructures and mechanical properties of Mg-Ca binary alloy. The results showed that yield strength of the as-extruded Mg-1.2 wt.% Ca ...alloys decrease from ∼ 360 MPa to ∼ 258 MPa as the ram speed increases from 0.4 mm/s to 2.4 mm/s, and the elongation increases from ∼ 3.9% to ∼ 12.2%. The microstructure changes from bimodal grain feature to the complete dynamical recrystallization (DRX) with increase of the extrusion speed. The ultrafine DRXed grains in size of ∼0.85 µm, the numerous nano-Mg2Ca particles dispersing along the grain boundaries and interiors, as well as the high density of residual dislocations, should account for the high strength. It is believed that the high degree of dynamic recrystallization and the resulting texture randomization play the critical roles in the ductility enhancement of the high-speed extruded Mg alloys.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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