Graph Data Processing and Analysis: From Algorithms to System Development

There are many real-world application domains where data can be naturally modelled as graphs, such as social networks and computer networks. The amount of data generated and published is rapidly increasing with the explosion of information. Effective storage of graph data and querying has become a significant challenge; hence the graph database is emerging to address this challenge. Graph databases have the unique advantages of modelling and querying complex relationships, capturing and navigating complex data relationships and recursive path querying when handling graph data. In this thesis, we enhance graph databases from both system and algorithm perspectives. Firstly, we propose two systems, SQL2Cypher and FSPS, to improve the usability and efficiency of graph databases. SQL2Cypher automatically migrates data from a relational database to a graph database. This system also supports translating SQL queries into Cypher queries. FSPS is the first FPGA-based system for accelerating graph queries on massive graphs. FSPS has the following features 1) a CPU-FPGA co-designed framework, 2) a fully pipelined FPGA execution, and 3) reduced data transfer from FPGA’s external memory. FSPS supports the two most fundamental types of graph queries, namely subgraph and path queries. Performance evaluation shows that FSPS outperforms the most popular graph database, Neo4j, by up to three orders of magnitude. All the draft demo videos can be found at https://www.youtube.com/watch?v=oSpHtJ8iVio and https://www.youtube.com/watch?v=eGaeBrVTJws. Secondly, the graph database does not widely support the cohesive subgraph models (i.e., Neo4j and PatMat). Many real-world relationships can be naturally represented as bipartite graphs such as customer-product, user-item, and author-paper. Therefore, we use efficient construct algorithms to investigate the bipartite hierarchy model. The bipartite hierarchy is the first model to discover the hierarchical structure of bipartite graphs based on the concept of (alpha, beta)-core and graph connectivity. These algorithms can effectively identify the affected regions to limit computation scope and avoid re-building the bipartite hierarchy from scratch. Extensive experiments on 10 real-world graphs demonstrate the effectiveness of the proposed bipartite hierarchy and validate the efficiency of our hierarchy constructions algorithms

An All-solid-state Cd2+-selective electrode with a low detection limit

A new all-solid-state Cd2+-selective electrode with a low detection limit was prepared by using conjugated thiophene oligomer alpha-sexithiophene (alpha-6T) as solid contact deposited between an ionophore-doped poly(vinyl chloride) membrane and a gold disc substrate. The electrode exhibited a Nernstian response for Cd2+ ions over a wide concentration range of 10(-3)-10(-7) M with a detection limit as low as 1.3 x 10(-8) M. Results showed that the fabricated potentiometric sensor was suitable for use within the pH range of 2.0-9.0 and exhibited good reproducibility for long-term measurements. (C) 2011 Elsevier B.V. All rights reserved.A new all-solid-state Cd2+-selective electrode with a low detection limit was prepared by using conjugated thiophene oligomer alpha-sexithiophene (alpha-6T) as solid contact deposited between an ionophore-doped poly(vinyl chloride) membrane and a gold disc substrate. The electrode exhibited a Nernstian response for Cd2+ ions over a wide concentration range of 10(-3)-10(-7) M with a detection limit as low as 1.3 x 10(-8) M. Results showed that the fabricated potentiometric sensor was suitable for use within the pH range of 2.0-9.0 and exhibited good reproducibility for long-term measurements. (C) 2011 Elsevier B.V. All rights reserved

Improved potentiometric response of all-solid-state Pb2+-selective electrode

Zero-current ion-flux has a great influence on the characteristics of the ion-selective electrodes. In this work the improvement of analytical performance of all-solid-state Pb2+-selective membrane electrodes was demonstrated by adjusting the transmembrane ion flux. The study is focused on the relationship between the conditioning solution and the linear working range of the obtained electrodes for different sample matrixes. Results show that the electrode with appropriate conditioning keeps good reproducibility within linear working range. The utility of the electrode has been tested by successfully determining Pb2+ concentration in real water samples. (c) 2012 Elsevier B.V. All rights reserved

Optimization of injection molding process parameters for the lining of IV hydrogen storage cylinder

Abstract The hydrogen storage cylinder lining was taken as the research object. The injection model of the cylinder liner was developed employing 3D software, a two-cavity injection molding system was built, and Moldflow was utilized for analysis to determine the best combination of injection molding process parameters. The effects of injection process parameters (melt temperature, mold temperature, holding pressure, holding time and cooling time) on the evaluation index were analyzed by orthogonal experiment L16(45). The prediction data of IV hydrogen storage cylinder lining under different parameters were obtained by the range analysis method. The multi-objective optimization problem of injection molding process was transformed into a single-objective optimization problem by using the grey correlation analysis method. The optimal parameters such as melt temperature 270 °C, mold temperature 80 °C, packing pressure 55 MPa, packing time 20 s and cooling time 13 s were obtained. Taguchi method was adopted to obtain SNR (signal-to-noise ratio), while range and variance methods were used for analysis. The results showed that warpage was 0.4892 mm, the volume shrinkage was 12.31%, the residual stress in the first direction was 98.13 MPa, and the residual stress in the second direction was 108.1 MPa. The comprehensive index was simultaneously most impacted by the melt temperature

Sober-Drive: A smartphone-assisted drowsy driving detection system

Drowsy driving, a combination of sleepiness and driving, has become a worldwide problem that often leads to tragic accidents and outcomes. Existing research findings have shown that the percentage of closure of eyelid (a.k.a PERCLOS) is an effective indicator to evaluate the driver's drowsiness. We present the Sober-Drive system, which leverages PERCLOS for on-vehicle drowsy driving detection using smart phones. Specifically, Sober-Drive is built upon a number of indicators that are discrete-approximated from PERCLOS, blink time and blink rate, and it exploits the Neural Network to classify the eye 'open/close' states. We developed a Sober-Drive prototype on Android smart phones, and we conducted extensive real-world experiments to evaluate its performance, the results of which show that Sober-Drive has a high detection rate of more than 90% for drowsy driving behaviors. ? 2014 IEEE.EICPCI-S(ISTP)

A solid-contact Pb2+-selective electrode using poly (2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene) as ion-to-electron transducer

In this work, a novel all-solid-state polymeric membrane Pb(2+)-selective electrode was developed by using for the first time poly(2-methoxy-5-(2&#39;-ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) as solid contact. To demonstrate the ion-to-electron transducing ability of MEH-PPV, chronopotentiometry and electrochemical impedance spectroscopy measurements were carried out. The proposed electrodes showed a Nernstian response of 29.1 mV decade(-1) and a lower detection limit of subnanomolar level. No water film was observed with the conventional plasticized PVC membrane. This work demonstrates a new strategy for the fabrication of robust potentiometric ion sensors. (C) 2011 Elsevier B.V. All rights reserved.</p

Partial substitution of chemical fertilizer by <i>Trichoderma</i> biofertilizer improved nitrogen use efficiency in wolfberry (<i>Lycium chinense</i>) in coastal saline land

A two-year field trial was conducted to investigate the effects of partial substitution of chemical fertilizer (CF) by Trichoderma biofertilizer (TF) on nitrogen (N) use efficiency and associated mechanisms in wolfberry (Lycium chinense) in coastal saline land. As with plant biomass and fruit yield, apparent N use efficiency and plant N accumulation were also higher with TF plus 75% CF than 100% CF, indicating that TF substitution promoted plant growth and N uptake. As a reason, TF substitution stabilized soil N supply by mitigating steep deceases in soil NH4+ -N and NO3-N concentrations in the second half of growing seasons. TF substitution also increased carbon (C) fixation according to higher photosynthetic rate (Pn) and stable C-13 abundance with TF plus 75% CF than 100% CF. Importantly, leaf N accumulation significantly and positively related with Pn, biomass, and fruit yield, and structural equation modeling also confirmed the importance of the causal relation of N accumulation coupled with C fixation for biomass and yield formation. Consequently, physiological and agronomical N use efficiencies were significantly higher with TF plus 75% CF than 100% CF. Overall, partial substitution of CF by TF improved N use efficiency in wolfberry in coastal saline land by stabilizing soil N supply and coupling N accumulation with C fixation

An Electrochemical Sensor Based on Gold and Bismuth Bimetallic Nanoparticles Decorated L-Cysteine Functionalized Graphene Oxide Nanocomposites for Sensitive Detection of Iron Ions in Water Samples

In this work, gold and bismuth bimetallic nanoparticles decorated L-cysteine functionalized graphene oxide nanocomposites (Au-BiNPs/SH-GO) were prepared and applied to selective detection of Fe(III) in lake and seawater samples by modifying onto glassy carbon electrodes. Bimetallic nanoparticles have various excellent properties and better catalytic properties because of the unique synergistic effect between metals. The modified electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. Under optimized conditions, current peak intensity increased linearly with increasing Fe(III) concentration over the range of 0.2–50 μM and a detection limit of 0.07 μM (S/N = 3). The Au-BiNPs/SH-GO/GCE was used for the determination of Fe(III) in lake and seawater samples with recoveries ranged from 90 to 103%. Those satisfactory results revealed the potential application of the Au-BiNPs/SH-GO electrochemical sensor for heavy metals detection in environmental monitoring

Self-luminescent europium based metal organic frameworks nanorods as a novel electrochemiluminescence chromophore for sensitive ulinastatin detection in biological samples

In this work, we developed a novel electrochemiluminescence (ECL) biosensor for ulinastatin (UTI) detection based on self-luminescent metal-organic framework (L-MOF) nanomaterials. The L-MOFs could be simply pre -pared by one-pot methods using Eu3+ and 4,4 ',4 ''-s-triazine-1,3,5-triyltri-m-aminobenzoic acid (H(3)TATAB) as the metallic center and organic ligand, respectively. The Eu-TATAB exhibited high efficiency and stable ECL performance when using K2S2O8 as coreactant. For the established biosensor, Eu-TATAB was both used as the ECL chromophore and protein carrier due to its outstanding biocompatibility and large superficial area, which could load sufficient antibodies to link with antigen in the biosensor for subsequent detection. The established sandwich ECL biosensor showed a wide linear range of 0.1 ng mL(-1) - 10(5) ng mL(-1) and a low limit of detection of 9.7 pg mL(-1 )for UTI detection. In addition, the developed ECL biosensor could also be successfully applied to the real UTI sample determination in serum. The reported biosensor strategy could provide a guide for developing more other novel and promising high-performance ECL nanomaterials, and also be used as a potential method for ultrasensitive UTI detection in disease research