Evolving Optical Networks for Latency-Sensitive Smart-Grid Communications via Optical Time Slice Switching (OTSS) Technologies

In this paper, we proposed a novel OTSS-assisted optical network architecture for smart-grid communication networks, which has unique requirements for low-latency connections. Illustrative results show that, OTSS can provide extremely better performance in latency and blocking probability than conventional flexi-grid optical networks.Comment: IEEE Photonics Society 1st Place Best Poster Award, on CLEO-PR/OECC/PGC 201

On QoS-assured degraded provisioning in service-differentiated multi-layer elastic optical networks

The emergence of new network applications is driving network operators to not only fulfill dynamic bandwidth requirements, but offer various grades of service. Degraded provisioning provides an effective solution to flexibly allocate resources in various dimensions to reduce blocking for differentiated demands when network congestion occurs. In this work, we investigate the novel problem of online degraded provisioning in service-differentiated multi-layer networks with optical elasticity. Quality of Service (QoS) is assured by service-holding-time prolongation and immediate access as soon as the service arrives without set-up delay. We decompose the problem into degraded routing and degraded resource allocation stages, and design polynomial-time algorithms with the enhanced multi-layer architecture to increase the network flexibility in temporal and spectral dimensions. Illustrative results verify that we can achieve significant reduction of network service failures, especially for requests with higher priorities. The results also indicate that degradation in optical layer can increase the network capacity, while the degradation in electric layer provides flexible time-bandwidth exchange.Comment: accepted by IEEE GLOBECOM 201

Optimization of PHEV Power Split Gear Ratio to Minimize Fuel Consumption and Operation Cost

A Plug-in Hybrid Electric Vehicle (PHEV) is a vehicle powered by a combination of an internal combustion engine and an electric motor with a battery pack. The battery pack can be charged by plugging the vehicle to the electric grid and from using excess engine power. The research activity performed in this thesis focused on the development of an innovative optimization approach of PHEV Power Split Device (PSD) gear ratio with the aim to minimize the vehicle operation costs. Three research activity lines have been followed: * Activity 1: The PHEV control strategy optimization by using the Dynamic Programming (DP) and the development of PHEV rule-based control strategy based on the DP results. * Activity 2: The PHEV rule-based control strategy parameter optimization by using the Non-dominated Sorting Genetic Algorithm (NSGA-II). * Activity 3: The comprehensive analysis of the single mode PHEV architecture to offer the innovative approach to optimize the PHEV PSD gear ratio

Genome replication engineering assisted continuous evolution (GREACE) to improve microbial tolerance for biofuels production

BACKGROUND: Microbial production of biofuels requires robust cell growth and metabolism under tough conditions. Conventionally, such tolerance phenotypes were engineered through evolutionary engineering using the principle of “Mutagenesis followed-by Selection”. The iterative rounds of mutagenesis-selection and frequent manual interventions resulted in discontinuous and inefficient strain improvement processes. This work aimed to develop a more continuous and efficient evolutionary engineering method termed as “Genome Replication Engineering Assisted Continuous Evolution” (GREACE) using “Mutagenesis coupled-with Selection” as its core principle. RESULTS: The core design of GREACE is to introduce an in vivo continuous mutagenesis mechanism into microbial cells by introducing a group of genetically modified proofreading elements of the DNA polymerase complex to accelerate the evolution process under stressful conditions. The genotype stability and phenotype heritability can be stably maintained once the genetically modified proofreading element is removed, thus scarless mutants with desired phenotypes can be obtained. Kanamycin resistance of E. coli was rapidly improved to confirm the concept and feasibility of GREACE. Intrinsic mechanism analysis revealed that during the continuous evolution process, the accumulation of genetically modified proofreading elements with mutator activities endowed the host cells with enhanced adaptation advantages. We further showed that GREACE can also be applied to engineer n-butanol and acetate tolerances. In less than a month, an E. coli strain capable of growing under an n-butanol concentration of 1.25% was isolated. As for acetate tolerance, cell growth of the evolved E. coli strain increased by 8-fold under 0.1% of acetate. In addition, we discovered that adaptation to specific stresses prefers accumulation of genetically modified elements with specific mutator strengths. CONCLUSIONS: We developed a novel GREACE method using “Mutagenesis coupled-with Selection” as core principle. Successful isolation of E. coli strains with improved n-butanol and acetate tolerances demonstrated the potential of GREACE as a promising method for strain improvement in biofuels production

Tyrosine decaging leads to substantial membrane trafficking during modulation of an inward rectifier potassium channel

Tyrosine side chains participate in several distinct signaling pathways, including phosphorylation and membrane trafficking. A nonsense suppression procedure was used to incorporate a caged tyrosine residue in place of the natural tyrosine at position 242 of the inward rectifier channel Kir2.1 expressed in Xenopus oocytes. When tyrosine kinases were active, flash decaging led both to decreased K+ currents and also to substantial (15–26%) decreases in capacitance, implying net membrane endocytosis. A dominant negative dynamin mutant completely blocked the decaging-induced endocytosis and partially blocked the decaging-induced K+ channel inhibition. Thus, decaging of a single tyrosine residue in a single species of membrane protein leads to massive clathrin-mediated endocytosis; in fact, membrane area equivalent to many clathrin-coated vesicles is withdrawn from the oocyte surface for each Kir2.1 channel inhibited. Oocyte membrane proteins were also labeled with the thiol-reactive fluorophore tetramethylrhodamine-5-maleimide, and manipulations that decreased capacitance also decreased surface membrane fluorescence, confirming the net endocytosis. In single-channel studies, tyrosine kinase activation decreased the membrane density of active Kir2.1 channels per patch but did not change channel conductance or open probability, in agreement with the hypothesis that tyrosine phosphorylation results in endocytosis of Kir2.1 channels. Despite the Kir2.1 inhibition and endocytosis stimulated by tyrosine kinase activation, neither Western blotting nor 32P labeling produced evidence for direct tyrosine phosphorylation of Kir2.1. Therefore, it is likely that tyrosine phosphorylation affects Kir2.1 function indirectly, via interactions between clathrin adaptor proteins and a tyrosine-based sorting motif on Kir2.1 that is revealed by decaging the tyrosine side chain. These interactions inhibit a fraction of the Kir2.1 channels, possibly via direct occlusion of the conduction pathway, and also lead to endocytosis, which further decreases Kir2.1 currents. These data establish that side chain decaging can provide valuable time-resolved data about intracellular signaling systems

Research on deformation monitoring of surrounding rock based on weak fiber grating sensing technology

The prominent contradiction between high ground stress and low strength of surrounding rock in deep strata of coal mine leads to large deformation and instability disaster after roadway excavation. In order to grasp the internal deformation of surrounding rock before and after roadway excavation and support in time, this study developed a quasi-distributed large-range strain sensor cable based on weak fiber grating sensing technology, and realized the 1 m-level spacing arrangement of deformation measuring points in surrounding rock. The test performance of the sensor cable is mastered through the indoor calibration test. The test results show that the strain range of the developed strain sensing cable is not less than 0.04, the sensitivity is 1.23 pm/με, and the accuracy level is 0.5. It belongs to the high-precision sensor and has good repeatability and linearity. Field industrial test was carried out in deep rock roadway of No. 4 Coal Mine of Pingdingshan Tian’an Coal Shares The results show that: The strain value of surrounding rock decreases with the increase of hole depth. The strain value of surrounding rock within 4 m is larger, and the strain value outside 7 m is smaller and tends to be stable. The strain of roadway surrounding rock mainly occurs within 30 days after roadway repair, and then the strain increase of roadway surrounding rock gradually decreases and tends to be stable. Taking the rapid convergence position of strain rate to 0 as the boundary of surrounding rock loose zone, the boundary of roadway side and top loose zone is 5 m, and the boundary of shoulder loose zone is 4 m. Through the comprehensive application of weak fiber grating technology and time division multiplexing technology, the strain optical cable greatly improves the multiplexing capacity of optical fiber sensing network and meets the large range and fine online monitoring requirements of surrounding rock deformation monitoring in deep roadway of coal mine. Through technical application, the internal deformation characteristics of surrounding rock of deep roadway in coal mine and the spatio-temporal evolution law of loose circle can be mastered in time, which provides scientific basic data for the stability control decision of surrounding rock of deep roadway