Linear Output Research Articles

LINEARITY TEST ANALYSIS OF AIRCRAFT RADIATION OUTPUT X-RAY FLUOROSCOPY

The number or intensity of X-ray photons produced correlates with the increase in tube current per time (mAs), which affects the image density on the final film. To ensure the consistency of the increase in X-ray radiation output and the Linear Coefficient of X-ray radiation output, is within the tolerance limits specified in PERKA BAPETEN Regulation Number 9 of 2011. The aim of this research is to determine the linearity of the X-ray Fluoroscopy radiation output in one of the houses. Jakarta sick. The method used is an experimental approach with a quantitative model. Measurement of radiation output using a PM1610 Personal Dosimeter on a Fluoroscopy aircraft. The results of measuring the linearity of X-ray radiation output with voltage variations of 40 kV, 50 kV, 60 kV, 70 kV show that the value of the Linearity Coefficient (CL) is (0.08 ; 0.06 ; 0.09 ; 0.07). So it can be said that the X-Ray Fluoroscopy equipment is in good condition because the CL value obtained in this study is below the Tolerance Limit Value according to PERKA BAPETEN Number 9 of 2011, namely CL ≤ 0.1 or ≤10%. This research can be carried out as a reference in further research

Simulation and Experimental Study of a Novel Negative-Pressure Flapper-Nozzle Mechanism.

As the manufacturing industry evolves, the significance of control valve positioners in chemical production escalates. The flapper-nozzle system, the heart of control valve positioners, directly influences the linearity of system control. Presently, studies on the flapper-nozzle system primarily focus on dynamic system modeling and computational fluid dynamics simulations. However, traditional flapper-nozzle mechanisms often fail to achieve linear control objectives. This paper proposes a novel negative-pressure nozzle structure to tackle this issue, combining computational fluid dynamics and experimental methods, and considering gas compressibility during high-speed flow. Both simulation and experimental results suggest that the new structure improves the supply air pressure and broadens the linear pressure output range of the system, showing significant potential for practical applications.

An Energy-Efficient Inverter-Based Voltage Reference Scheme with Wide Output Range Using Correlated Level Shifting Technique

A voltage reference is indispensable in Integrated Circuits. To improve the limited linear output voltage range and energy efficiency of a voltage reference, we innovatively propose a switched-capacitor-based programmable voltage reference scheme employing inverter-based OTAs to reduce the power consumption, simultaneously using a novel Correlated Level Shifting (CLS) technique (without active overhead) to enhance the OTA’s DC gain and integral gain. Experimented with SMIC 180 nm CMOS technology, a scheme-based voltage reference realizes a programable output voltage range from 266 to 995 mV at −30 to 120 °C, and the corresponding temperature coefficient (TC) ranges from 82.4 to 99.5 ppm/°C. The power consumption is 976 nW. Furthermore, comparative experiments and evaluations with other schemes have unequivocally verified the superiority of our proposed scheme, characterized by its high energy efficiency and wide output voltage range. The scheme can be suitably deployed in a multitude of novel edge-data processing systems.

Post-FEC performance evaluation of optical SDM systems with mode-dependent loss

This work is focused on the bit error rate (BER) performance of spatial division multiplexing (SDM) systems over an optical channel with mode-dependent loss or gain (collectively referred to in this paper as MDL). When the latter is non-negligible, the BER has a random nature that introduces the outage probability as an important performance metric for the system design and also impacts on the selection of a forward-error correction (FEC) scheme. In MDL-impaired SDM systems, the pre-FEC BER is a random variable whose probability density function (PDF) and coding gain depend on the signal-to-noise ratio (SNR) at the receiver input. Hence, the common and simple approach of adding a coding gain factor to the pre-FEC BER to obtain the post-FEC BER is not adequate, and numerical simulations are needed. In this paper, we simulate and analyze the performance in terms of post-FEC BER for two proposals of applying low-density parity check (LDPC) FEC encoder/decoder in a SDM system MDL-impaired and an optimal linear multiple input multiple output (MIMO) receiver. In the first one, the LDPC is applied independently to each mode, and in the second one, the LDPC is applied among all SDM modes. Simulation results indicate that the first proposal outperforms the second. Simplifications in the log-likelihood ratio (LLR) computations have also been considered.

Finite-time stabilization of discrete-time conewise linear systems

The finite-time stabilizing control design problem for discrete-time conewise linear systems is tackled in this paper. Such a class of systems consists of the union of ordinary linear time-invariant subsystems, whose dynamics are defined in prescribed conical regions, constituting a conical partition of the state space. By imposing some cone-copositivity properties to a suitable piecewise quadratic function, two sufficient conditions are preliminarily derived concerning the system’s finite-time stability. By building on them, novel results are then presented for the system’s finite-time stabilization through a piecewise linear output feedback controller. Such results are based on the solution of feasibility problems involving sets of Linear Matrix Inequalities (LMIs). A numerical example illustrates the effectiveness of the proposed approach.

Retracted: Analysis of the Characteristics in Linear Generator for EDS Maglev Based on Harmonic Magnetic Field Method

The optimal non-contact onboard power source for superconducting electrodynamics suspension (EDS) maglev is the linear generator. As a result, the development of the linear generator has been significantly aided by the research of its properties. A method for figuring out the maximum output power of the EDS maglev's linear generator is suggested. It has the advantages of a straightforward formulation, quick calculation time, and acceptable precision. First, the electromagnetic model of the linear generator taking into account the eddy current loss of the outer vessel is constructed in accordance with the structure of EDS maglev. Second, the magnetic flux density of superconducting (SC) coils and the multi-structure figure-8 shaped coils containing harmonic components are expressed using Fourier coefficients utilizing the harmonic magnetic field approach, and this is done by incorporating the structural correction coefficient of SC coils. Third, it is proposed to use variable resistance to equivalent eddy current losses to calculate the linear generator's maximum output power. Finally, the finite element (FEM) simulation and the measurement data of the Yamanashi line are used to confirm that the theory is valid.

Fully Distributed Formation Flying Control of Multiple Spacecraft by Observer-Based Linear Output Protocols

Fully Distributed Formation Flying Control of Multiple Spacecraft by Observer-Based Linear Output Protocols

Linear Output Regulation for Unknown Stable Systems With Uncertain Minimum-Phase Actuators

Consider a linear stable system - described by the transfer function <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P(s)$</tex-math></inline-formula> of unknown parameters, unknown order, and unknown relative degree - under a linear exosystem generating biased multi-sinusoidal references and/or disturbances with at most <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$q$</tex-math></inline-formula> different known frequencies <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\omega _{i}$</tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$i=1,\ldots,q$</tex-math></inline-formula> . It has been recently established that a linear regulator with minimal order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$(2q+1)$</tex-math></inline-formula> exists under the knowledge of the positive or negative signs of: i) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P(0)$</tex-math></inline-formula> ; ii) either <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Re (P(j\omega _{i}))$</tex-math></inline-formula> or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Im (P(j\omega _{i}))$</tex-math></inline-formula> , for any <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$i=1,\ldots,q$</tex-math></inline-formula> [ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$j$</tex-math></inline-formula> is the imaginary unit]. This technical note explores the case in which the measurable input <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$u$</tex-math></inline-formula> to the aforementioned system is provided by an unknown linear actuator. It is actually shown that the regulator design can be naturally extended to such a scenario, provided that the actuator process is minimum-phase, of known relative degree <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\rho \geq 1$</tex-math></inline-formula> and with known sign of the high-frequency gain.

Proportions of Green Area and Tree Health on University Campus: The Impact of Pavement Presence

Sustainable urban ecosystems require healthy green spaces that provide ecological services to meet social and environmental needs. This study evaluates the proportion of green areas in the urban campus and assesses the effects of pavement on the health of Samanea saman. The MAPIR Normalised Difference Vegetation Index (NDVI) camera mounted on a drone captured a proportion of green areas of approximately 27.80%, which is roughly a quarter of the total study sites. However, the significance of green areas depends on the health of the trees. Therefore, the pavement effects on the health status of trees in green areas were studied using Visual Tree Assessment (VTA) and aerial image analysis using the MAPIR (NDVI) camera on a drone. Although both methods evaluate health status, the final outputs differed. VTA produced categorical outputs, which assigned trees into health categories based on a visual assessment of factors. In contrast, NDVI produced linear outputs, which provided a numerical value to demonstrate tree health. Both methods indicate that trees in non-paved areas are healthier, particularly for the excellent trees identified by the VTA, which suggests that pavement negatively impacts tree health. However, the effects of paved and non-paved areas on tree health status analysis using the aerial image are not significant (p&gt;0.05), which may be due to the low quality and accuracy of the images. The study provides insights into the importance of green areas and tree health in creating sustainable urban ecosystems.

Characterization of an Onboard Transmission Detector for Efficient Linear Accelerator Output Quality Assurance

Characterization of an Onboard Transmission Detector for Efficient Linear Accelerator Output Quality Assurance

Optimizing quantum noise-induced reservoir computing for nonlinear and chaotic time series prediction

Quantum reservoir computing is strongly emerging for sequential and time series data prediction in quantum machine learning. We make advancements to the quantum noise-induced reservoir, in which reservoir noise is used as a resource to generate expressive, nonlinear signals that are efficiently learned with a single linear output layer. We address the need for quantum reservoir tuning with a novel and generally applicable approach to quantum circuit parameterization, in which tunable noise models are programmed to the quantum reservoir circuit to be fully controlled for effective optimization. Our systematic approach also involves reductions in quantum reservoir circuits in the number of qubits and entanglement scheme complexity. We show that with only a single noise model and small memory capacities, excellent simulation results were obtained on nonlinear benchmarks that include the Mackey-Glass system for 100 steps ahead in the challenging chaotic regime.

Hierarchical Echo State Network With Sparse Learning: A Method for Multidimensional Chaotic Time Series Prediction.

Echo state network (ESN), a type of special recurrent neural network with a large-scale randomly fixed hidden layer (called a reservoir) and an adaptable linear output layer, has been widely employed in the field of time series analysis and modeling. However, when tackling the problem of multidimensional chaotic time series prediction, due to the randomly generated rules for input and reservoir weights, not only the representation of valuable variables is enriched but also redundant and irrelevant information is accumulated inevitably. To remove the redundant components, reduce the approximate collinearity among echo-state information, and improve the generalization and stability, a new method called hierarchical ESN with sparse learning (HESN-SL) is proposed. The HESN-SL mines and captures the latent evolution patterns hidden from the dynamic system by means of layer-by-layer processing in stacked reservoirs, and leverage monotone accelerated proximal gradient algorithm to train a sparse output layer with variable selection capability. Meanwhile, we further prove that the HESN-SL satisfies the echo state property, which guarantees the stability and convergence of the proposed model when applied to time series prediction. Experimental results on two synthetic chaotic systems and a real-world meteorological dataset illustrate the proposed HESN-SL outperforms both original ESN and existing hierarchical ESN-based models for multidimensional chaotic time series prediction.

A Comparative Study about Accuracy Levels of Resistance Temperature Detectors RTDs Composed of Platinum, Copper, and Nickel

Platinum, copper, and nickel were founded the best metals used in resistance temperature detectors RTDs. They commonly used in laboratory and industrial applications because they provide accurate and reliable measurements in a wide temperature range from (- 200 to 850 °C). They have high conductivity, sensitivity, and hardness to resist strain shock, pressure, and vibration. The accuracy level of them depends on reliability, stability, repeatability, linearity, and response to time. This study aims to determine and compare the accuracy of these three metals in regarding to their features which include stability, repeatability, and response time. The study has gathered and analyzed the data of these suitable and precise metals and compared with each other. The results showed that platinum is widely needed for RTDs due to its precision, stability, higher accuracy, and linearity output, while copper and nickel are not stable or repeatable as platinum. It was indicated that temperature coefficient of resistance TCR for nickel is bigger and for copper is medium, but for platinum is lower.

Optic cup and disc segmentation model based on linear attention and dual attention

Glaucoma is one of blind causing diseases. The cup-to-disc ratio is the main basis for glaucoma screening. Therefore, it is of great significance to precisely segment the optic cup and disc. In this article, an optic cup and disc segmentation model based on the linear attention and dual attention is proposed. Firstly, the region of interest is located and cropped according to the characteristics of the optic disc. Secondly, linear attention residual network-34 (ResNet-34) is introduced as a feature extraction network. Finally, channel and spatial dual attention weights are generated by the linear attention output features, which are used to calibrate feature map in the decoder to obtain the optic cup and disc segmentation image. Experimental results show that the intersection over union of the optic disc and cup in Retinal Image Dataset for Optic Nerve Head Segmentation (DRISHTI-GS) dataset are 0.962 3 and 0.856 4, respectively, and the intersection over union of the optic disc and cup in retinal image database for optic nerve evaluation (RIM-ONE-V3) are 0.956 3 and 0.784 4, respectively. The proposed model is better than the comparison algorithm and has certain medical value in the early screening of glaucoma. In addition, this article uses knowledge distillation technology to generate two smaller models, which is beneficial to apply the models to embedded device.

Single-frequency pulsed fiber laser based on an electro-optic modulator with injection seeding technique.

A single-frequency linearly polarization pulsed fiber laser based on an electro-optic modulator with injection seeding technique is demonstrated. The single-frequency performance of the fiber ring-cavity laser is guaranteed by the seed source, which is a distributed-feedback fiber laser based on the π-phase-shifted fiber Bragg grating. The electro-optic modulator triggers active Q-switching of the laser for pulse generation. The devices used in the fiber laser are all polarization-maintaining to ensure linear polarization laser output. Through parameter optimization, the laser generates a single-frequency linearly polarization pulsed laser with a central wavelength of 1064.22nm, linewidth of 35MHz, and polarization extinction ratio of better than 40dB. This type of fiber laser can be applied in lidar, beam combining, nonlinear frequency conversion, and other fields.

Robust fault reconstruction using sliding mode observers with nonlinear nominal systems

This paper is concerned with fault reconstruction based on sliding mode observers; its contribution is twofold: on the one hand, it develops a novel sliding mode observer whose nominal system is nonlinear, thus relaxing former limitations on the subject, namely, rank restrictions, linear outputs, and conservative bounds; on the other hand, based on the referred sliding mode observer, a novel robust fault reconstruction scheme is constructed which can solve a variety of problems that former methodologies cannot treat. Nonlinearities are cast as convex expressions, which enables obtaining design conditions in the form of linear matrix inequalities. Examples are provided to compare the proposal with former methodologies, thus highlighting the contributions.

Half-Bridge Silicon Strain Gauges with Arc-Shaped Piezoresistors.

Half-bridge silicon strain gauges are widely used in the fabrication of diaphragm-type high-pressure sensors, but in some applications, they suffer from low output sensitivity because of mounting position constraints. Through a special design and fabrication approach, a new half-bridge silicon strain gauge comprising one arc gauge responding to tangential strain and another linear gauge measuring radial strain was developed using Silicon-on-Glass (SiOG) substrate technology. The tangential gauge consists of grid patterns, such as the reciprocating arc of silicon piezoresistors on a thin glass substrate. When two half-bridges are connected to form a full bridge with arc-shaped gauges that respond to tangential strain, they have the advantage of providing much higher output sensitivity than a conventional half-bridge. Pressure sensors tested under pressure ranging from 0 to 50 bar at five different temperatures indicate a linear output with a typical sensitivity of approximately 16 mV/V/bar, a maximum zero shift of 0.05% FS, and a span shift of 0.03% FS. The higher output level of pressure sensing gauges will provide greater signal strength, thus maintaining a better signal-to-noise ratio than conventional pressure sensors. The offset and span shift curves are quite linear across the operating temperature range, giving the end user the advantage of using very simple algorithms for temperature compensation of offset and span shift.

Using harmonic beam combining to generate pulse-burst in nonlinear optical laser

The ultrashort lasers working in pulse-burst mode reveal great machining performance in recent years. The number of pulses in bursts effects greatly on the removal rate and roughness. To generate a more equal amplitude of pulses in burst with linear polarization output and time gap adjustable, we propose a new method by the harmonic beam combining (HBC). The beam combining is commonly used in adding pulses into the output beam while maintaining the pulse waveform and beam quality. In the HBC, dichroic mirrors are used to combine laser pulses of fundamental wave (FW) into harmonic wave (HW), and nonlinear crystals are used to convert the FW into HW. Therefore, HBC can add arbitrarily more HW pulses to generate pulse-burst in linear polarization with simple structure. The amplitude of each pulse in bursts can be adjusted the same to increase the stability of the burst, the time gap of each pulse can be adjusted precisely by proper time delay. Because HBC adds pulses sequentially, the peak power density of the burst is the same as each pulse, pulses can be combined without concern of back-conversion which often occurs in high peak power density. In the demonstration, the extendibility of HBC was verified by combining two beams with a third beam. The combined efficiency rates were larger than 99%, and the beam quality of each beam was maintained at M 2 ≈ 1.4.

Design and Control of an Analog Optical Switch Based on the Coupling of an Electrothermal Actuator and a Mass–Spring System

Extending the analog output function has become an important trend in current MEMS optical switches. The electrothermal actuator is a potential candidate for realizing the analog optical switch since the output displacement can be continuously controlled throughout its driving range. However, since most existing micromirrors employ the out-of-plane motion, which is directly driven by the actuator, the design flexibility is limited and the temperature effect cannot be ignored. In this article, an analog optical switch is designed based on the coupling of an electrothermal actuator, a mass–spring system, and a sidewall reflective optical path. The in-plane reciprocating motion of the sidewall reflection micromirror is realized through the coupling, with the load analysis of the optical switch being significantly simplified. A temperature decrease as high as 305.5 K can be achieved by the integration at an applied voltage of 15 V. The dynamic coupling mechanism is well explained by a multibody electro-thermal–mechanical model. Furthermore, a position sensorless control scheme is proposed to realize the analog output function and anti-interference of the coupling optical switch. The linear analog output is presented throughout the micromirror's displacement of 0–90.57 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m. We believe that this work is significant for providing a novel functional device in intelligent optical window, laser ignition system, optical neural computing, etc.

Microring structure for flexible polymer waveguide-based optical pressure sensing.

Flexible pressure sensors provide a promising platform for artificial smart skins, and photonic devices provide a new technique to fabricate pressure sensors. Here, we present a flexible waveguide-based optical pressure sensor based on a microring structure. The waveguide-based optical pressure sensor is based on a five-cascade microring array structure with a size of 1500 µm × 500 µm and uses the change in output power to linearly characterize the change in pressure acting on the device. The results show that the device has a sensing range of 0-60 kPa with a sensitivity of 23.14 µW/kPa, as well as the ability to detect pulse signals, swallowing, hand gestures, etc. The waveguide-based pressure sensors offer the advantages of good output linearity, high integration density and easy-to-build arrays.