Extra Operations Research Articles

Development of a modified quick, easy, cheap, effective, rugged, and safe method based on melamine sponge for multi-residue analysis of veterinary drugs in milks by ultra-performance liquid chromatography tandem mass spectrometry

The purpose of this study was to develop a modified QuEChERS method based on melamine sponge for rapid determination of multi-class veterinary drugs in milks by UPLC-MS/MS. Through simple infiltration and extrusion, fast and convenient matrix purification could be achieved within several seconds, and there was no need of extra phase separation operations. Good linearity with correlation coefficient (R2) ≥0.999 was obtained for all drugs in the range of 2~500 µg·kg−1. The obtained matrix effects were within ±20% for all monitored drugs. The recoveries of all monitored drugs ranged from 60.7% to 116.0% at three spiked levels (50, 100, and 200 µg·kg−1), with relative standard deviations less than 7.4%. Comparatively low LODs and LOQs were obtained in the ranges of 0.1~3.8 µg·kg−1 and 0.2~6.3 µg·kg−1, respectively. Compared with conventional purification adsorbents, melamine sponge yielded an equal or higher purification performance with matrix removal rate as high as 52.5% and acceptable recoveries in range of 60%-120% for all monitored drugs. The satisfactory results have demonstrated the good potential of melamine sponge in matrix purification for rapid determination of multiclass residues in food safety.

Investigating indirect impacts of TCP connection on IMS network

The IP Multimedia Subsystem (IMS) is recently expected to have the major architecture framework to be involved in the Next Generation Network. IMS works to bridge the multimedia communication among variety of applications over Internet. IMS bears its multimedia signals and stream through different means of transport protocols; TCP, UDP, and SCTP. TCP is a connection-oriented protocol that provides reliable data delivery and congestion control. To setup connection with TCP, IMS entities requires extra operations to complete, that operation process called (worker process) costs the multimedia server extra overload and delay. This paper investigates the indirect impacts of TCP connection that resulted from the Call Session Control Function (CSCF) servers when it deal with video communication. Two parameters are evaluated in experiment which are CPU usage and response time with two different scenarios. The experimental shows that outbound scenario performs better than the inbound scenario due to the extra operations required to setup new TCP connection for inbound

Rapid quantitative detection for multiple antibiotics in honey using a quantum dot microsphere immunochromatographic strip

We design a honey antibiotic detection system (HADS), which provides honey antibiotic residue rapid on-site detecting solution relying on simple sample preparation tactics, lateral-flow immunochromatographic assay (LFIA)-based strip and handheld sensor reader. Relying on the quantum dot microsphere probes conjugated to the antibiotic monoclonal antibodies, the LFIA strip can simultaneously detect sulfonamides (SAs) and tetracyclines (TCs) in high sensitivity with extremely low detecting limits of 0.4 μg/kg and good specificity. Moreover, the fabricated LFIA strips can be well conserved in vacuum-sealed bags at 4 °C for at least 6 months. Combining with the handheld sensor reader, both SAs and TCs can be quantitatively and automatically measured in high accuracy. All the operations including sample preparation and detection can be finished within 20 min at room temperature on site without any extra devices or complicated operations. • We design honey antibiotic detection system (HADS) for antibiotic residue detection. • HADS can detect sulfonamides (SAs) and tetracyclines (TCs) in high sensitivity. • HADS supports rapid (20 min) and cost-effective (75 cents) antibiotic detection. • HADS is proved with high accuracy, good stability, selectivity and specificity. • HADS supports rapid on-site detection for honey antibiotic residues.

Some improvements of hybrid trim method for a helicopter rotor in forward flight

The main difficulty of the trimming for helicopter rotor CFD (Computational Fluid Dynamics) lies in the high computational cost and low computational efficiency. The BET/CFD hybrid trim method, which uses the low-fidelity BET (Blade Element Theory) to calculate the Jacobian matrix and high-fidelity CFD method to get the aerodynamic force and moment for comparison with the target values, has been widely used in industry due to its high efficiency and low computational cost compared with the pure CFD method. However, this method also has two disadvantages: a complex C81 table needs to be established before the BET works; because of the low accuracy in computing the Jacobian matrix, the number of trim iterations is too large and the trimming may not even converge. In this paper, two improvements of the hybrid trim method have been proposed. Firstly, an Artificial Neural Networks (ANN) model has been developed to predict the aerodynamic coefficients in the BET. The ANN model greatly improves the efficiency and works for all kinds of airfoils without any extra operation. The second improvement is to divide the trimming process into two stages: the preliminary stage in which the Jacobian matrix is calculated using the BET with an ANN model, and the accurate stage in which the Jacobian matrix is obtained by the CFD method. The two-stage method avoids the second shortcoming mentioned above. The AH-1G rotor and ONERA 7A rotor in forward flight have been investigated to validate the present method. The trim results agree well with the flight test results and other computational results.

Ghost Difference Imaging Using One Single-Pixel Detector

How can a target's differential image of multiple components at a certain degree of freedom (DOF) of light (e.g., wavelength, polarization, and position) be obtained? Previous schemes often need two steps, i.e., first collecting each component of the target simultaneously with multiple detectors or sequentially with a single detector, then performing the difference operation in the digital postprocessing. Based on the principle of computational ghost imaging (GI), we here take advantage of the natural complementarity in space to design an illumination mode, which is no longer the spatiotemporal fluctuation of photon number (light intensity) but the photons with different components under the same DOF. By applying this engineered illumination to computational GI, termed ghost difference imaging (GDI), we can achieve differential imaging of multiple components of a certain DOF in a single-round acquisition using only one single-pixel detector with no extra digital-subtraction operations but higher SNR. Both multiwavelength-difference GDI and position-difference GDI are well demonstrated in simulations and experiments. Further, the GDI scheme reduces the number of sampling times for differential imaging while also increasing photons' utilization. Our work, therefore, provides an insight for GI modality, along with a straightforward and low-cost update of the light path, which is suitable for all computational GI systems using the digital micromirror device.

Encryption scheduling for remote state estimation under an operation constraint

In remote state estimation, data transmitted by a sensor through a wireless communication channel may be overheard by an eavesdropper. One possible way to avoid information leakage is to encrypt the transmitted data all the time. However, this may impose an extra operation energy burden on the sensor. In this paper, we investigate the optimal encryption scheduling in order to protect data privacy and ensure estimation accuracy under an energy constraint. Specifically, the sensor computes its local state estimate and then quantizes it using a non-subtractively dithered quantizer. Before each transmission, the sensor determines whether encrypting the data or not in order to strike a balance between data privacy and estimation accuracy. As the information about eavesdropper is unknown to the estimator, we introduce the concept of eavesdropper-invariant schedules and derive associated structural results. In addition, we propose a practical algorithm that compares a finite number of points to obtain an ε-optimal encryption schedule. Numerical examples are provided to illustrate performance benefits of the proposed methods.

ESco: Eligibility score-based strategy for sensors selection in CR-IoT: Application to LoRaWAN

In this paper, a battery-powered Internet of Things assisting Cognitive Radio (CR-IoT) network is considered. In CR-IoT network, a set of IoT End Nodes (ENs) are assumed to cooperatively sense the channel. Each EN performs a Spectrum Sensing (SS) and reports its decision to a Fusion Center in order to reach the decision on the PU status. Such monitoring of PU comes at the cost of additional energy resources consumed by the EN to perform SS and reporting, and raises the need to set a suitable protocol to manage the data exchange. The extra operations may exhaust the energy of the EN battery, especially when Low Power Wide Area Networks (LPWAN) technology is used. In our manuscript, an Eligibility Score-based (ESco) Strategy is defined to reflect the eligibility of an EN to make a reliable SS taking into consideration its battery level. Our strategy is adapted to LoRaWAN Class-B protocol in order to handle real world scenarios. Necessary modifications are introduced to the existing protocol in order to support the synchronization between the ENs and the Application Server, (at which the SS need is identified), and the on-demand nature of the SS requests. To evaluate our strategy, LoRa sensors’ parameters are considered in our simulations. The numerical results highlight the efficiency of the proposed strategy by showing the extension of the ENs’ lifetime compared to classical strategies.

Incision and flap design during total auricular reconstruction using a 2-stage strategy.

BackgroundTotal auricular reconstruction is a challenge for plastic surgeons. Expanded flap method and Nagata’s method with autologous costal cartilage are two leading techniques for ear reconstruction. And a two-stage strategy of expanded flap method received attention. In the present study, we report the incision and flap design of this strategy.MethodsIn the first stage, an 80 mL kidney-shaped expander was inserted in the mastoid region with the larger pole superiorly. The expander pocket was dissected subcutaneously in the scalp area and subfascially in the lower third region. In the second stage, the expander was removed from a Y-shaped lobule incision on the remanent ear. Then the remnant ear was separated into three flaps: the posterior skin flap, anterior skin flap, and lobule flap. When the framework was fabricated, the base frame and the underlying pad, which enhanced the projection, were fixed together as a whole to provide a more prominent appearance. The framework was totally wrapped into the expanded single flap without free skin grafting. Lobule transposition and tragus construction were performed simultaneously instead of a third-stage surgery. The recipient bed of rotated lobule was resected only to the epidermal layer and the subcutaneous layer was preserved to avoid central necrosis.ResultsA total of 21 patients received this strategy to reconstruct ear. With 3 months to 1.5 years of follow-up, 19 patients (90.5%) were satisfied with the reconstructed ears. 3 patients (14.3%) required further modification of reconstructed ear. No serious complications occurred during the procedures.ConclusionsWith a Y-shaped incision, three-flap design of remanent ear and lobule rotation to an epidermal-removal area, tissue expander removal and modification of remanent ear can be performed effectively to avoid necrosis and an extra operation.

Solvent-free synthesis of phytosterol linoleic acid esters at low temperature.

Phytosterol unsaturated fatty acid esters show much higher oil solubility than free phytosterol. Thus, development of a green and low-cost method for the preparation of phytosterol fatty acid esters is highly desirable in the food industry. Herein, we have developed a simple chemical method toward efficient preparation of phytosterol linoleic acid esters at very mild temperature (60 °C) using 4-dodecylbenzenesulfonic acid (DBSA) as the catalyst. In this work, low-temperature esterification of phytosterols (soybean sterol) with linoleic acid could produce the corresponding phytosterol esters above 95% conversion under solvent-free conditions. In addition, this simple method could be applied to produce phytosterol esters through esterification of phytosterol with an unsaturated fatty acid mixture resulting from the hydrolysis of various vegetable oils. Importantly, no extra organic solvents and no extra water-removal operations or equipment were required in this chemical esterification method. The mechanism investigation suggested that the DBSA-catalyzed low-temperature esterification would form micro-emulsions of water-in-oil (W/O), which could achieve automatic separation of water from the hydrophobic system to avoid reverse reaction hydrolysis and rapidly promote the equilibrium reaction towards phytosterol esters.

Fast normalized cross-correlation for measuring distance to objects using optic flow, applied for helicopter obstacle detection

The fast normalized cross-correlation (NCC) calculation method presented here features low computational requirements, which makes it suitable for being implemented in real time onboard micro-controllers with very few computational resources. This method was adapted for making distance measurements, using a high speed optic flow sensor operating at 20m∕s. An application of this study is to develop a proof of concept of an innovative optic flow sensor fixed at the tip of an helicopter’s blade (from Airbus Helicopter) to measure the distance to various obstacles (wall, cliff...) in the azimuthal plane (rotor plane) during hovering flight. Due to its small size, this sensor developed in this paper can also be also adapted for Micro aerial vehicles (MAVs). This method of calculation requires less memory than the reference method, at the expense of some extra arithmetical operations, but it is still significantly lighter than the classical NCC method. An algorithm for implementing this method in real-time robotic applications is presented. Experimental results confirm the efficiency of this highly time-saving method.

Covariant propagator and chiral power counting

Some one-loop diagrams with one and two external baryons/nucleons are revisited using covariant baryon propagators in chiral effective theory. We showed that it is enough to separate and subtract all the local terms that violate chiral power counting to recover chiral power counting, no need to introduce extra operations. The structures of leading chiral corrections and IR enhancement or threshold effects are ‘stable’ or persist as long as covariant propagators are employed for all particles.

Causality, subjectivity and mental spaces: Insights from on-line discourse processing

Abstract Research has shown that it requires less time to process information that is part of an objective causal relation describing states of affairs in the world (She was out of breath because she was running), than information that is part of a subjective relation (She must have been in a hurry because she was running) expressing a claim or conclusion and a supporting argument. Representing subjectivity seems to require extra cognitive operations. In Mental Spaces Theory (MST; Fauconnier, Gilles. 1994. Mental spaces: Aspects of meaning construction in natural language. Cambridge: MIT Press) the difference between these two relation types can be described in terms of an extra mental space in the discourse representation of subjective relations: representing the Subject of Consciousness (SoC). In processing terms, this might imply that the processing difference is not present if this SoC has already been established in the discourse. We tested this prediction in two eye tracking experiments. The results of Experiment 1 showed that signaling the subjectivity of the relation by introducing a subject of consciousness beforehand did not diminish the processing asymmetry compared to a neutral context. However, the relative complexity of subjective relations was diminished in the context of Free Indirect Speech (No! He was absolutely sure. There was no doubt about it. She was running so she was in hurry; Experiment 2). In terms of MST and the representation of subjectivity in general, this implies that not only creating a representation of a thinking subject, but also assigning a claim to this thinking subject requires extra processing effort.

A Unified Numerical Scheme for Coupled Multiphysics Model

For oil and gas exploration, seismic wave propagation in coupled acoustic, elastic, poroelastic, and even anisotropic media is a valuable aspect. However, it is a challenging task to deal with the interfaces of the coupled model. In order to tackle the specific issue, a unified numerical scheme is developed, which is based on the discontinuous Galerkin method. The acoustic, elastic, poroelastic, and anisotropic elastic wave equations are unified into a first-order velocity–stress system. The numerical simulation at the interfaces in the coupled model is conveniently handled by the Godunov flux without any extra operations. Numerical results from the coupled acoustic–elastic and acoustic–poroelastic model are compared with the analytic solutions. In addition, the rates of convergence from different orders are analyzed, which demonstrates the accuracy of the proposed numerical scheme. The surface waves at the fluid–solid interface are studied. Moreover, the proposed scheme is applied to a more complex coupled model, including the coupled acoustic–elastic–poroelastic model and the coupled acoustic–anisotropic elastic model. The corresponding results demonstrate that the proposed numerical scheme is capable of dealing with the coupled model.

Optical multiple-image compression-encryption via single-pixel Radon transform.

Compression is a common operation in multiple-image encryption (MIE) schemes. For most of the existing MIE schemes, the compression process would lead to the waste of the detect data. In this paper, a novel MIE scheme based on the single-pixel Radon transform (RT) is proposed. In the encryption process, the single-pixel RT of each image from 0° to 180° is performed. This process can be realized by an optical setup. All Radon spectra are combined and encrypted by the asymmetric cryptosystem based on phase-truncated Fourier transforms (PTFT). To increase the security, the Arnold map and logistic map are used to scramble and diffuse the result of PTFT. Unlike conventional MIE schemes, there is no extra compression operation and data waste in the proposed method. The key sensitivity, the multiplexing capacity, and the security under various attacks are analyzed through simulation results. The optical experiment is also performed to demonstrate the feasibility of the proposed optical MIE scheme.

HYBRID POWER SYSTEM FOR A FUEL STATION CONSIDERING TEMPERATURE COEFFICIENT

It is crystal clear that appropriate technical sizing has a significant effect on the techno-economic analysis of an off-grid standalone energy system. As a result, this study presents the effect of incorporating the temperature coefficient in the optimal analysis of an off-grid hybrid system using a standard fuel (gas) station in Nigeria as a case study. Comparative analysis with and without the temperature coefficient was performed. The results showed that the inclusion of temperature coefficient leads to extra operation hours of the generator which will result in an increase in fuel consumption and annual operation cost of the diesel generator. Also, the initial cost of the PV/BAT/diesel is relatively higher than the diesel generator but, the generating emission of the hybrid system is lower when compared to the diesel-only which enhances the atmospheric condition of the society.

Boosting Bit-Error Resilience of DNN Accelerators Through Median Feature Selection

Deep learning techniques have enjoyed wide adoption in real life, including in various safety-critical embedded applications. While neural network computations require protection against hardware errors, the substantial overheads of conventional error-tolerance techniques limit their use on embedded platforms, which carry out demanding deep neural network computations with limited resources. The utilization of conventional techniques is further constrained in high error rate scenarios, increasingly prevalent under aggressive energy and performance optimizations. To resolve this conundrum, we introduce a novel median feature selection technique to filter the impact of bit errors prior to the execution of each layer. While our technique can be deemed as a fine-grained modular redundancy scheme, its construction purely out of the inherent redundancy of the network necessitates neither additional parameters nor extra multiply-accumulate operations, squashing the inordinate overheads typically associated with such techniques. Median feature selection can be efficiently performed in hardware and seamlessly integrated into embedded deep learning accelerators as a modular plug-in. Deep learning models can be trained with standard tools and techniques to ensure a graceful operational interface with the feature selection stages. The proposed technique allows the system to perform accurately even at high error rates by improving its resilience up to four orders of magnitude, yet incurs negligible 0.19%–0.48% area and 0.07%–0.19% power overheads for the required operations.

A compact image encryption system based on Arnold transformation

A novel compact image encryption system is proposed based on Arnold transformation (AT). In general, AT is a pixel-scramble tool in image encryption, but its security is not high enough as an independent cryptosystem because of its periodicity. Hence, extra diffusion operations are needed to diffuse the pixel values to acquire the higher security. Here an encryption algorithm is proposed by AT. Firstly, the corresponding coordinates of each pixel in original image are calculated by AT. Secondly, the pixel values of the two corresponding coordinates are disturbed by another AT. These two processes can diffuse the pixel values of the original image. At last, the diffused image is pixel scrambled by AT with different parameters. This is the confusion process. In proposed scheme, the diffusing and confusing operations are both realized by AT. At the same time, the image is encrypted as a pixel distribution instead of a data stream. The key space, key sensitivity, the correlation, the cost time and the security of proposed cryptosystem are analyzed and the results confirm that the proposed image encryption algorithm demonstrates extraordinary performance.

Efficient FEC Scheme for Solar-Powered WSNs Considering Energy and Link-Quality

In solar-powered wireless sensor networks (SP-WSNs), the best use of harvested energy is more important than minimizing energy consumption since energy can be supplied periodically. Meanwhile, as is well known, the reliability of the communication between sensor nodes is very limited due to the resource constraints of sensor nodes. In this paper, we propose an efficient forward error correction (FEC) scheme which can give solar-powered wireless sensor networks more reliable communication. First, the proposed scheme provides energy-adaptive operation for the best use of solar energy. It calculates the amount of surplus energy which can be used for extra operations and then determines the number of additional parity bits for FEC according to this amount of surplus energy. At the same time, it also provides a link quality model that is used to calculate the appropriate number of parity bits for error recovery required for the current data communication environment. Finally, by considering these two parity sizes, it is possible to determine the number of parity bits that can maximize the data reliability without affecting the blacking out of nodes. The evaluation of the performance of the approach was performed by comparing the amount of data collected at the sink node and the number of blackout nodes with other schemes.

Advanced four‐mode‐modulation‐based four‐switch non‐inverting buck–boost converter with extra operation zone

This study proposes a novel non-inverting buck–boost converter topology with extra-wide operational zones under both continuous current mode (CCM) and discontinuous current mode (DCM), by introducing a four-mode modulation (4MM) strategy. The proposed 4MM method is able to eliminate the operation dead zone, thus extending the operation zones of the buck–boost converter to contain boost mode, extended boost mode, extended buck mode, and buck mode. Rigorous analyses and design principles are presented in detail to demonstrate the four-mode function through CCM and DCM operational investigations and illustrations. Theoretical analyses and parameter design are verified by software simulation and hardware experimentation in this study, which validates the proposed 4MM method and the functionality of the proposed 4MM-based buck–boost converter. They clearly indicate the superiority of the proposed 4MM-based four-switch non-inverting buck–boost converter over its conventional counterparts, posing wide applicability in industrial practices.

An Error Amplifier With a Low Power Multi-Mode Voltage Clamper for Transient Enhancement and High Reliability

This paper proposes a low power area-efficient multi-mode voltage clamper circuit called pseudo differential pair and applies it into an error amplifier (EA) which can be used in DC-DC converters as a practical design example. In addition to a normal amplifying mode, the error amplifier has two extra operation modes with the help of the voltage clamper, which can limit the maximum output voltage and the maximum sink current, respectively. By inserting this pseudo differential pair of only three transistors in the intermediate stage of the amplifier, a voltage-current feedback is introduced to achieve the voltage limiting function without bringing resistive load to the output stage or unwanted effects to the input stage. The frequency compensation of the EA is also reused in the voltage limiting loop to make the whole block more compact. The circuit is implemented in a $0.35~\mu \text{m}$ BCD process. The verification results match the theoretical analysis very well, which proves that the proposed voltage clamper can effectively enhance transient response of the converter control loop and improve system reliability. Only additional 0.001689 mm2 active area is occupied for about 2X transient speed improvement with fair open loop amplifying performance.