Host Platform Research Articles

Development of Synchronized High-Sensitivity Wireless Accelerometer for Structural Health Monitoring.

The use of digital accelerometers featuring high sensitivity and low noise levels in wireless smart sensors (WSSs) is becoming increasingly common for structural health monitoring (SHM) applications. Improvements in the design of Micro Electro-Mechanical System (MEMS) based digital accelerometers allow for high resolution sensing required for SHM with low power consumption suitable for WSSs. However, new approaches are needed to synchronize data from these sensors. Data synchronization is essential in wireless smart sensor networks (WSSNs) for accurate condition assessment of structures and reduced false-positive indications of damage. Efforts to achieve synchronized data sampling from multiple WSS nodes with digital accelerometers have been lacking, primarily because these sensors feature an internal Analog to Digital Converter (ADC) to which the host platform has no direct access. The result is increased uncertainty in the ADC startup time and thus worse synchronization among sensors. In this study, a high-sensitivity digital accelerometer is integrated with a next-generation WSS platform, the Xnode. An adaptive iterative algorithm is used to characterize these delays without the need for a dedicated evaluation setup and hardware-level access to the ADC. Extensive tests are conducted to evaluate the performance of the accelerometer experimentally. Overall time-synchronization achieved is under 15 µs, demonstrating the efficacy of this approach for synchronization of critical SHM applications.

Misalignment Error Suppression Between Host Frame and Magnetic Sensor Array

Magnetic sensor array is usually designed for object detection and localization, where sensor coordinate is required to be consistent. Misalignment angles between coordinates should be calculated and calibrated. A new calibration method is proposed in order to calibrate the misalignment error between host frame and sensors. Host platform frame and perpendicular platform are used to obtain misalignment angles of sensor array. Experiment results show that it can estimate all angles of magnetic sensors and suppress misalignment error. Misalignment rms error is a reduction from 1109.7 to 27.6 nT, which means 2.48% indeed, thus improving the remote sensing accuracy of array which is unified to host frame coordinate.

A novel knock out strategy to enhance recombinant protein expression in Escherichia coli

BackgroundThe expression of recombinant proteins triggers a stress response which downregulates key metabolic pathway genes leading to a decline in cellular health and feedback inhibition of both growth and protein expression. Instead of individually upregulating these downregulated genes or improving transcription rates by better vector design, an innovative strategy would be to block this stress response thereby ensuring a sustained level of protein expression.ResultsWe postulated that the genes which are commonly up-regulated post induction may play the role of signalling messengers in mounting the cellular stress response. We identified those genes which have no known downstream regulatees and created knock outs which were then tested for GFP expression. Many of these knock outs showed significantly higher expression levels which was also sustained for longer periods. The highest product yield (Yp/x) was observed in a BW25113ΔcysJ knock out (Yp/x 0.57) and BW25113ΔelaA (Yp/x 0.49), whereas the Yp/x of the control W3110 strain was 0.08 and BW25113 was 0.16. Double knock out combinations were then created from the ten best performing single knock outs leading to a further enhancement in expression levels. Out of 45 double knock outs created, BW25113ΔelaAΔyhbC (Yp/x 0.7) and BW25113ΔcysJΔyhbC (Yp/x 0.64) showed the highest increase in product yield compared to the single gene mutant strains. We confirmed the improved performance of these knock outs by testing and obtaining higher levels of recombinant asparaginase expression, a system better suited for analysing sustained expression since it gets exported to the extracellular medium.ConclusionCreating key knock outs to block the CSR and enhance expression is a radically different strategy that can be synergistically combined with traditional methods of improving protein yields thus helping in the design of superior host platforms for protein expression.

Genomics and transcriptomics analysis reveals the mechanism of isobutanol tolerance of a laboratory evolved Lactococcus lactis strain

Isobutanol, in spite of its significant superiority over ethanol as a biofuel, remains commercially non-viable due to the non-availability of a suitable chassis which can handle the solvent toxicity associated with its production. To meet this challenge, we chose Lactococcus lactis which is known for its ability to handle environmental stress and carried out Adaptive laboratory evolution (ALE) in a continuous stirred tank reactor (CSTR) to evolve an isobutanol tolerant strain. The strain was grown for more than 60 days (> 250 generations) while gradually increasing the selection pressure, i.e. isobutanol concentration, in the feed. This led to the evolution of a strain that had an exceptionally high tolerance of up to 40 g/l of isobutanol even though a scanning electron microscope (SEM) study as well as analysis of membrane potential revealed only minor changes in cellular morphology. Whole genome sequencing which was done to confirm the strain integrity also showed comparatively few mutations in the evolved strain. However, the criticality of these mutations was reflected in major changes that occurred in the transcriptome, where gene expression levels from a wide range of categories that involved membrane transport, amino acid metabolism, sugar uptake and cell wall synthesis were significantly altered. Analysing the synergistic effect of these changes that lead to the complex phenotype of isobutanol tolerance can help in the construction of better host platforms for isobutanol production.

Using queuing theory to describe adaptive mathematical models of computing systems with resource virtualization and its verification using a virtual server with a configuration similar to the configuration of a given model

The article describes the issues of preparation and verification of mathematical models of computing systems with resource virtualization. The object of this study is to verify of mathematical models of computer systems with virtualization experimentally by creating a virtual server on the host platform and monitoring its characteristics under load. Known models cannot be applied to the aircraft with virtualization, because they do not allow a comprehensive analysis to determine the most effective option for the implementation of the initial allocation of resources and its optimization for a specific sphere and task of use. The article for the study used a closed queueing network. Simple models for the analysis of various structures of computer systems are experimentally obtained. To implement the properties of adaptability in the models, triggers are used that monitor and adjust the power of the processing channel in individual Queuing systems, depending on the specified conditions. Experiments prove the obtained results reliable and usable as a flexible tool for studying the virtualization properties when structuring computing systems. This knowledge could be of use for businesses interested in optimizing the server configuration for their IT infrastructure.

A new misalignment calibration method of portable geomagnetic field vector measurement system

Abstract Geomagnetic field is widely used for remote sensing, environment observation, geoscience and geology research. A portable geomagnetic field vector measurement system is designed, but misalignment greatly influences measurement accuracy. It is calibrated by establishing interim coordinate without measuring the projection of geomagnetic field and gravity. In addition, earth's magnetic dip, the accurate attitude of equipment and careful operation in collection process are not need. It is easy to implement the experiment, and misalignment angles between sensors are calculated. Magnetometer, inertial navigation system, host platform frame and perpendicular platform are used in experiment. After calibration, North, Vertical and East vector measurement error are reduced to 3.9%, 4.7% and 6.6% respectively. Inclination and declination error are reduced from 4.374° and 4.974° to 0.173° and 0.309° respectively. Thus, it is convenient and effective for misalignment calibration.

Guest-oriented non-fullerene acceptors for ternary organic solar cells with over 16.0% and 22.7% efficiencies under one-sun and indoor light

Abstract Given that the ring-fusion strategy can effectively tail the electrical, optical, and structural properties of π-conjugated materials, we have herein developed Y-series non-fullerene acceptors with a dual acceptor–donor–dual acceptor-type structure, bearing non-fused bare bithiophene (Y–Th2), hexagonal ring-fused bithiophene (Y-BDT), or pentagonal ring-fused bithiophene (Y-CDT) central donor units. Several characterization techniques were applied to perform a comparative investigation of their optical and physical properties and frontier energy levels with respect to the different ring-fusion of the central units. Moreover, for the cascade energy level alignment, the synthesized acceptors were employed as a third component in the PM6:Y6 that served as a binary host platform. The introduction of the optimal amount of Y–Th2 or Y-BDT into the host system improved the device performance. Specifically, Y–Th2 exhibited the best power conversion efficiency (PCE) (16.01%) along with improved photovoltaic parameters, whereas the addition of Y-CDT impaired the PCE. Moreover, the optimized Y–Th2-based ternary organic solar cell achieved a PCE of 22.72% under indoor illumination at 1000 lux. Thus, the in-depth structural, morphological, and electrical analyses not only established a structure–property correlation, but also provided better design criteria for the guest-oriented non-fullerene acceptors for ternary photovoltaic applications, especially for Y6-containing systems.

Experimental Analysis and Evaluation of RaptorQ Codes for Video Multicasting Over Wi-Fi

This paper presents a reliable and efficient high quality video streaming solution for use in challenging outdoor environments over Wi-Fi. An application layer forward error correction based on RaptorQ codes was implemented in a practical Wi-Fi based server and client system to enhance reliability. Thus, this paper presents the first detailed analysis on the implementation of RaptorQ codes for streaming high definition video over Wi-Fi. The measurements were performed in central Bristol with parameters such as RaptorQ symbol size, code rate, buffering time and modulation and coding scheme, and user quality of experience based on these parameters was evaluated. For multicast live video streaming it is demonstrated that system performance is mostly dominated by hardware and software limitations on constrained host platforms where the incoming packet rate exceeds the device`s ability to consume the traffic, i.e., Wi-Fi clients are a major source of packet loss, even in ideal channel conditions. Client limitations were found to be a function of modulation and coding schemes and RaptorQ coding parameters. Therefore, the optimum system design parameters such as RaptorQ symbol size, code rate and buffering time with respect to modulation and coding schemes were suggested considering practical limitations from real-world measurements.

Sustainable production of FAEE biodiesel using the oleaginous yeast Yarrowia lipolytica.

Fatty acid ethyl esters (FAEEs) are fatty acid‐derived molecules and serve as an important form of biodiesel. The oleaginous yeast Yarrowia lipolytica is considered an ideal host platform for the production of fatty acid‐derived products due to its excellent lipid accumulation capacity. In this proof‐of‐principle study, several metabolic engineering strategies were applied for the overproduction of FAEE biodiesel in Y. lipolytica. Here, chromosome‐based co‐overexpression of two heterologous genes, namely, PDC1 (encoding pyruvate decarboxylase) and ADH1 (encoding alcohol dehydrogenase) from Saccharomyces cerevisiae, and the endogenous GAPDH (encoding glyceraldehyde‐3‐phosphate dehydrogenase) gene of Y. lipolytica resulted in successful biosynthesis of ethanol at 70.8 mg/L in Y. lipolytica. The engineered Y. lipolytica strain expressing the ethanol synthetic pathway together with a heterologous wax ester synthase (MhWS) exhibited the highest FAEE titer of 360.8 mg/L, which is 3.8‐fold higher than that of the control strain when 2% exogenous ethanol was added to the culture medium of Y. lipolytica. Furthermore, a synthetic microbial consortium comprising an engineered Y. lipolytica strain that heterologously expressed MhWS and a S. cerevisiae strain that could provide ethanol as a substrate for the production of the final product in the final engineered Y. lipolytica strain was created in this study. Finally, this synthetic consortium produced FAEE biodiesel at a titer of 4.8 mg/L under the optimum coculture conditions.

Performance Analysis of Constrained Device Virtualization Algorithm

Internet of Things aims to automate and add intelligence into existing processes by introducing constrained devices such as sensors and actuators. These constrained devices lack in computation and memory resources and are usually battery powered for ease of deployments. Due to their limited capabilities, the constrained devices usually host proprietary protocols, platforms, data formats and data structures for communications and therefore, are unable to communicate with devices from different vendors. This inability leads to interoperability issues in Internet of Things which, is in fact against the spirit of Internet of things which, envisions interconnection of billions of devices and hence, results in an isolated, vendor-locked and close-loop deployments of IoT solutions. Various approaches have been made by the industry and academia to resolve the interoperability issues amongst constrained devices. However, majority of the solutions are at different layers of the communication stack but do not provide a holistic solution for the problem. In more recent research, there have been theoretical proposals to virtualize constrained devices to abstract their data so that its always available to applications. We have adopted this technique in our research to virtualize the entire Internet of Things network so that virtual TCP/IP based protocols can operate on virtual networks for enabling interoperability. This paper proposes the operations of the Constrained Device Virtualization Algorithm and then simulates it in CloudSIM to derive performance results. The paper further highlights open issues for future research in this area.

Container description ontology for CaaS

Besides its classical three service models (IaaS, PaaS, and SaaS), container as a service (CaaS) has gained significant acceptance. It offers without the difficulty of high-performance challenges of traditional hypervisors deployable applications. As the adoption of containers is increasingly wide spreading, the use of tools to manage them across the infrastructure becomes a vital necessity. In this paper, we propose a conceptualisation of a domain ontology for the container description called CDO. CDO presents, in a detailed and equal manner, the functional and non-functional capabilities of containers, Dockers and container orchestration systems. In addition, we provide a framework that aims at simplifying the container management not only for the users but also for the cloud providers. In fact, this framework serves to populate CDO, help the users to deploy their application on a container orchestration system, and enhance interoperability between the cloud providers by providing migration service for deploying applications among different host platforms. Finally, the CDO effectiveness is demonstrated relying on a real case study on the deployment of a micro-service application over a containerised environment under a set of functional and non-functional requirements.

Container description ontology for CaaS

Besides its classical three service models (IaaS, PaaS, and SaaS), container as a service (CaaS) has gained significant acceptance. It offers without the difficulty of high-performance challenges of traditional hypervisors deployable applications. As the adoption of containers is increasingly wide spreading, the use of tools to manage them across the infrastructure becomes a vital necessity. In this paper, we propose a conceptualisation of a domain ontology for the container description called CDO. CDO presents, in a detailed and equal manner, the functional and non-functional capabilities of containers, Dockers and container orchestration systems. In addition, we provide a framework that aims at simplifying the container management not only for the users but also for the cloud providers. In fact, this framework serves to populate CDO, help the users to deploy their application on a container orchestration system, and enhance interoperability between the cloud providers by providing migration service for deploying applications among different host platforms. Finally, the CDO effectiveness is demonstrated relying on a real case study on the deployment of a micro-service application over a containerised environment under a set of functional and non-functional requirements.

XUAVs: Towards Efficient Approximate Computing for UAVs—Low Power Approximate Adders With Single LUT Delay for FPGA-Based Aerial Imaging Optimization

High Definition (HD) image processing and real-time analytics over live video feeds have always been the key requirements for Intelligence, Surveillance and Reconnaissance (ISR) applications. With the evolution of optics and image enhancement techniques, computational loads of HD ISR systems are also rising exponentially. On the contrary, the slow-down of Moore's Law has recently posed challenging bounds over the level of achievable miniaturization for emerging processing and storage units. Field Programmable Gate Arrays (FPGAs) offer a popular choice of implementing ISR algorithms over resource-constrained platforms, such as Unmanned Aerial Vehicles (UAVs), due to favorable features of reconfigurability and rapid prototyping. A promising solution to bridge the gap between resource-constrained host platforms and computation-intensive FPGA applications is the paradigm of Approximate Computing. It compromises on the accuracy of processed results to offer significant performance gains for error-tolerant applications, such as video and image processing. In this paper, we present a novel approximate adder design methodology, for FPGA-based systems with improved SWaP performance, besides preserving the accuracy requirements within acceptable thresholds. The design methodology proposed in this paper focuses on the FPGA-specific Look-Up Table (LUT) architecture to introduce approximations while splitting the carry chain into LUT-based sub-adders, with flexible overlap to tune the adder's accuracy and achieve the overall latency of a single LUT. The paper presents several variants of the proposed design and offers application-oriented flexibility to adjust for optimal SWaP vs accuracy trade-off. We have further devised a comprehensive assessment approach to verify functional viability of the proposed atomic arithmetic blocks at system level, through their implementation into dense computational imaging applications, such as 2-dimensional Discrete Cosine Transform (DCT), airborne self-localization and moving object tracking algorithms, in comparison with other state-of-the-art adders. Our most accurate design performs at least 9.9% better in power consumption when compared with existing approximate adders, which proves that the proposed methodology holds promising potential to improve SWaP-index for computation-intensive UAV applications.

Mapping out the Degree of Freedom of Hosted Enzymes in Confined Spatial Environments

Summary The integration of enzymes with solid materials is crucial for promoting their industrialization. Understanding the enzyme behavior upon association within a confined space, though of fundamental importance for biocomposite development, remains a persistent, unresolved challenge. Here, we present a comprehensive elucidation of the spatial environment’s impact on hosted enzymes’ degree of freedom and, consequently, their accompanying reactivity. Site-directed spin labeling in combination with electron paramagnetic resonance spectroscopy allows the direct detection of host-guest interactions at atomic resolution, while the tailorable synthesis of covalent organic frameworks (COFs) enables an evaluation of factors affecting such interactions. Specifically, lysozyme is found to be more constrained and less active along with increasing hydrophilicity of the COFs. These results support the establishment of a connection between the hydrophilicity of the spatial environment and the resulting biocomposites’ reactivity, enabling the prediction of the performance of unknown biocomposites. This study provides a unique insight into the mechanistic pathways underpinning biocatalysis.

Vision-based edge detection between plant column and soil of ningxia lycium barbarum garden

ABSTRACTThe cultivation of Lycium barbarum (L.barbarum) is a highly traditional and advantageous industry in Ningxia, China, and has strong development prospects. At present, the protection, fertilization, picking, and other production aspects of L.barbarum are generally inefficient and labor intensive, presenting a bottleneck that restricts the development of the industry. Developing intelligent production equipment in the form of a ‘general self-moving host platform + operation module’ is an urgent task for the healthy development of the L.barbarum industry. A self-planning, self-organizing, host platform must be able to perform adaptive navigation in complex unstructured environments. For this purpose, a method of edge detection that can distinguish between the plant column and soil is required. Using a color difference model with Otsu’s method for image segmentation, a corrected gradient image based on the marking method is employed to remove small noise regions and then perform edge detection. Experiments demonstrate that one particular color model offers strong adaptability for light and shadow, which is good for distinguishing between the plant column and soil. The proposed method can effectively detect the edges between the plant column and soil, laying the foundation for detecting a suitable path for a self-moving platform and visual navigation.

Streamlined Pseudomonas taiwanensis VLB120 Chassis Strains with Improved Bioprocess Features.

Microbes harbor many traits that are dispensable or even unfavorable under industrial and laboratory settings. The elimination of such traits could improve the host's efficiency, genetic stability, and robustness, thereby increasing the predictability and boosting its performance as a microbial cell factory. We engineered solvent-tolerant Pseudomonas taiwanensis VLB120 to yield streamlined chassis strains with higher growth rates and biomass yields, enhanced solvent tolerance, and improved process performance. In total, the genome was reduced by up to 10%. This was achieved by the elimination of genes that enable the cell to swim and form biofilms and by the deletion of the megaplasmid pSTY and large proviral segments. The resulting strain GRC1 had a 15% higher growth rate and biomass yield than the wildtype. However, this strain lacks the pSTY-encoded efflux pump TtgGHI, rendering it solvent-sensitive. Through reintegration of ttgGHI by chromosomal insertion without (GRC2) and with (GRC3) the corresponding regulator genes, the solvent-tolerant phenotype was enhanced. The generated P.taiwanensis GRC strains enlarge the repertoire of streamlined chassis with enhanced key performance indicators, making them attractive hosts for biotechnological applications. The different solvent tolerance levels of GRC1, GRC2, and GRC3 enable the selection of a fitting host platform in relation to the desired process requirements in a chassis à la carte principle. This was demonstrated in a metabolic engineering approach for the production of phenol from glycerol. The streamlined producer GRC1Δ5-TPL38 outperformed the equivalent nonstreamlined producer VLB120Δ5-TPL38 concerning phenol titer, rate, and yield, thereby highlighting the added value of the streamlined chassis.

Stable hole transport type host boosting the efficiency and lifetime of the exciplex host based phosphorescent organic light-emitting diodes

A strong hole transport type host (p-type host) for exciplex host application was developed for stable device lifetime in green phosphorescent organic light-emitting diodes. The hole transport type host, 3,3′-bis(5-phenylindolo[3,2-a]carbazol-12(5H)-yl)-1,1′-biphenyl (IDCzBP), was designed to have indolocarbazole unit for strong hole transport property and stability under positive polaron state. The IDCzBP worked as the p-type host in the exciplex host and extended the device lifetime of the green phosphorescent organic light-emitting diodes by 11 times with reference to conventional p-type host. Furthermore, the IDCzBP host had an efficiency boosting effect in the green devices. Analysis of the device behavior informed that the improved stability under positive polaron state is responsible for the upgraded device lifetime. A maximum external quantum efficiency of 20.3% and lifetime extension by 11 times were registered in the green phosphorescent organic light-emitting diodes with a host platform of IDCzBP embedded exciplex host.

Gel microdroplet–based high-throughput screening for directed evolution of xylanase-producing Pichia pastoris

Xylanases have useful applications in a wide range of industries. In this regard, Pichia pastoris has become one of the most attractive host platforms for large-scale production of xylanases. However, genomic engineering is still required for overexpression and efficient secretion. In this paper, we applied droplet-based method to screen directed evolved extracellular xylanase producing P.pastoris strain. Xylanase-producing P.pastoris cells were encapsulated in gel microdroplets with a fluorogenic reporter substrate. Improved production of xylanase increases fluorescence intensity of gel microdroplets, enabled accurate selection of evolved clones by droplet sorting. The screening strategy was validated by identifying yeast with improved xylanase production from a mixed sample with a positive selection accuracy of up to 98%. After three rounds of mutagenesis and selection, approximately 108 variants were screened, and a P.pastoris clone with more than 1.3-fold increase in xylanase activity was identified, representing cellular functions improvement of the production host. The throughput of this approach was at least 103-fold higher than that of the robot-assisted microtiter plate reader, and reagent consumption was reduced by ∼106-fold. Furthermore, the greatly shortened incubation time prior screening significantly accelerated the process of directed evolution.

FireSim: FPGA-Accelerated Cycle-Exact Scale-Out System Simulation in the Public Cloud

In this article, we present FireSim, an open-source simulation platform that enables fast cycle-exact microarchitectural simulation of large scale-out clusters by combining FPGA-accelerated simulation of silicon-proven RTL designs with scalable, distributed network simulation, running on a public-cloud host platform. By introducing automation and harnessing cloud FPGAs, FireSim provides the usability and productivity of software full-system simulators with the high performance and accuracy of FPGA-accelerated simulation, while adding the unprecedented ability to scale to globally cycle-accurate simulations of thousands of networked nodes. To demonstrate FireSim's scalability, we automatically generate and deploy a target cluster simulation of 1024 3.2-GHz quad-core server nodes, each with 16 GB of DRAM, interconnected by a 200 Gb/s network with low latency, which simulates at a 6.6-MHz processor clock rate ($< $<500× slowdown over real time). In aggregate, this simulation harnesses millions of dollars of FPGAs—at a cost of only hundreds of dollars per simulation-hour to users.

Design of intelligent window system based on cloud platform

This paper designs and develops intelligent window system based on the cloud platform of Newland Group. The system designed can be divided into two parts: monitoring host and remote monitoring platform. The monitoring host controls a variety of sensors to monitor noise, rain, burglary, carbon monoxide concentration, etc. At the same time, two motors are used to realize automatic control, and data is uploaded to the cloud platform through the WIFI module, and functions such as monitoring and logical control are realized. Through the remote monitoring platform, users can obtain real-time data, switch window on and off, adjust the percentage of window open, or judge that someone turns over the window and automatically closes the window, and inform the householder by text message, etc. Actual test results show that the system developed in this paper can work normally and the hardware cost of the system is less than 500 RMB, which is worthy of promotion and application.