Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling and Simulation of Large-Scale Manipulators with Hydraulic Actuation

Abstract Due to the light-weight construction of modern large-scale manipulators used e.g., in concrete pumps or maritime crane systems, the elasticity of the construction elements plays a significant role in the dynamic behaviour of the overall system. These systems are vulnerable to vibrations caused by external disturbances like the pumping of wet concrete, the wave motions on the sea or disturbances induced by the manual control of the operator. Therefore, current research is concerned with control strategies for active damping of elastic vibrations, trajectory planning and the computation of the inverse kinematics. For the development of such control methods, tailored mathematical models are required. In the considered applications, the inhomogeneous distribution of mass and of the geometrical moment of inertia over the length of the segments of the boom has to be explicitly considered in the model which makes the problem more involved. Furthermore, it is known that significant static friction occurs in the hydraulic cylinders used to actuate the boom. Since this can be a major problem in the design of a control strategy, this effect has to be taken into account in the model. This paper presents a systematic approach for the mathematical modeling of hydraulically actuated large-scale manipulators, taking into account both elasticity and static friction. The feasibility of the modeling approach will be proven by measurement results of an industrial mobile concrete pump.
Performance enhancement of limited-bandwidth active automotive suspensions by road preview

A refined approach for the implementation of preview control in discrete time based on methods from earlier work is given. This allows the use of multiple preview inputs and reduces the system order of a discrete-time preview system significantly with respect to former methods, while describing the dynamic system in an exact form and yielding an equivalent control law. This method is applied to a limited-bandwidth quarter-car system, which incorporates an actuator in series with a passive spring, the combination being in parallel with a passive damper. Control design is carried out using discrete-time linear quadratic regulator (LQR) theory with tyre deflection, suspension working space, vertical body acceleration and control demand. How the optimal preview control law works in a physical sense is worked out regarding the feedforward gain matrix. It is shown that, as a part of the optimal control strategy, the preview controller "concentrates" in some sense on what it can do best for any amount of preview time. The conclusions from that are backed up considering performance indices and their components for variation of preview time, actuator bandwidth and the constraints in the cost function. Emphasis is put on the investigation of how the actuator bandwidth influences the performance capabilities of the system. General relationships between cast reduction, cost-component reduction, preview time and system bandwidth are exposed. By increasing preview time, the cost function can be reduced until it reaches a saturation value, which depends on the actuator bandwidth chosen. Increasing the actuator bandwidth beyond a certain value has only a small influence on the preview time needed for the diminishing returns to set in. Improving the road holding requires fast actuators, but comparatively short preview distances. Ride comfort can be influenced by a rather slow controller, but requires a long preview time.
Prediction of engine NOx for virtual sensor using deep neural network and genetic algorithm

The Nitrogen Oxides (NOx) from engines aggravate natural environment and human health. Institutional regulations have attempted to protect the human body from them, while car manufacturers have tried to make NOx free vehicles. The formation of NOx emissions is highly dependent on the engine operating conditions and being able to predict NOx emissions would significantly help in enabling their reduction. This study investigates advanced method of predicting vehicle NOx emissions in pursuit of the sensorless engine. Sensors inside the engine are required to measure the operating condition. However, they can be removed or reduced if the sensing object such as the engine NOx emissions can be accurately predicted with a virtual model. This would result in cost reductions and overcome the sensor durability problem. To achieve such a goal, researchers have studied numerical analysis for the relationship between emissions and engine operating conditions. Also, a Deep Neural Network (DNN) is applied recently as a solution. However, the prediction accuracies were often not satisfactory where hyperparameter optimization was either overlooked or conducted manually. Therefore, this study proposes a virtual NOx sensor model based on the hyperparameter optimization. A Genetic Algorithm (GA) was adopted to establish a global optimum with DNN. Epoch size and learning rate are employed as the design variables, and R-squared based user defined function is adopted as the object function of GA. As a result, a more accurate and reliable virtual NOx sensor with the possibility of a sensorless engine could be developed and verified.
The Application of Computer Simulation in Manufacturing

In manufacturing, the use of computer simulation has led to significant benefits: risk reduction, greater understanding, operating cost reduction, lead time reduction, faster plant changes, and capital cost reduction. However, these benefits are rarely attained, since only a few manufacturing managers are aware of the technology. Discusses simulation, its benefits and the range of manufacturing issues to which it can be applied. A case study describes how simulation was used at the Ford Motor Company to improve work organization and determine human resource requirements.
LPNet: Retina Inspired Neural Network for Object Detection and Recognition

The detection of rotated objects is a meaningful and challenging research work. Although the state-of-the-art deep learning models have feature invariance, especially convolutional neural networks (CNNs), their architectures did not specifically design for rotation invariance. They only slightly compensate for this feature through pooling layers. In this study, we propose a novel network, named LPNet, to solve the problem of object rotation. LPNet improves the detection accuracy by combining retina-like log-polar transformation. Furthermore, LPNet is a plug-and-play architecture for object detection and recognition. It consists of two parts, which we name as encoder and decoder. An encoder extracts images which feature in log-polar coordinates while a decoder eliminates image noise in cartesian coordinates. Moreover, according to the movement of center points, LPNet has stable and sliding modes. LPNet takes the single-shot multibox detector (SSD) network as the baseline network and the visual geometry group (VGG16) as the feature extraction backbone network. The experiment results show that, compared with conventional SSD networks, the mean average precision (mAP) of LPNet increased by 3.4% for regular objects and by 17.6% for rotated objects.
CALCULATION AND RECOVERY OF HOME OFFICE OVERHEAD

When construction is delayed by owner-caused actions, contractors request compensation for the delay. It is difficult to reach agreement on the causes and extent of delay and even tougher to agree on the cost of delay, especially the component costs of home office overhead. This is due, in part, to the lack of a single, accepted method of calculating home office overhead. This paper explores nine methods of calculating such damages and shows the results of each. It also discusses the new rules developed by Federal Courts and Boards of Contract Appeals concerning the recovery of “unabsorbed overhead”.
Design and Analysis of Micro strip High Pass Filter with Modified Ground Structure for L & S Band

The performance of a high pass filter (HPF) with and without modified ground structure for L and S Band is analyzed in this specific work. The modified ground structure includes 4 circles and 2 hexagonal etched shapes in ground plane. Calculation and comparison of the response of both shape filters was done separately. Parameters of the proposed configuration were calculated at the cut off frequency of 1.67 GHz and also proposed designs with dielectric constant of 4.4, loss tangent of 0.02 and substrate height of 1.6mm. Results were simulated using computer simulation technology software (CST). The undesired sidebands and fluctuations of response are reduced by using modified ground structure. Also the cut off point of the high pass filer is shifted to a higher frequency and an improvement in selectivity as well as in Bandwidth for L and S band (1 to 3 GHz).
Gigabit transmitter array modules on silicon waferboard

Individually addressable, four-channel transmitter arrays operating at data rates of 1 Gb/s have been developed based on a hybrid optoelectronic integration approach called silicon waferboard. A key feature of silicon waferboard is the use of mechanical alignment features fabricated on the surface of a silicon chip that enable passive optical alignment of components such as lasers and optical fibers. The transmitter array, which operates at a wavelength of 1.3 mu m, comprises a four-channel InGaAsP/InP laser array that is passively aligned to four single-mode fibers held in V-grooves. The transmitter array also includes a four-channel GaAs MESFET driver array chip that provides high-speed drive currents to the individual lasers. The laser array, driver array, and optical fibers are all spaced on 350- mu m centers, which results in a four-channel transmitter array that fits within a width of only 2 mm. Transmitter array waferboards were housed in a specially developed package to permit high-frequency characterization. These transmitter array modules have demonstrated operation at data rates of 1 Gb/s per channel, with an interchannel crosstalk of -29 dB. >
CARACTERIZAÇÃO DE BIOMASSAS PARA A BRIQUETAGEM

O objetivo deste trabalho foi caracterizar a producao de briquetes feita a partir de quatro diferentes biomassas residuais. Foram utilizados os residuos de serragem de Eucalyptus sp, serragem de Pinus sp, bagaco de cana-de-acucar ( Saccharum officinarum L.) e palha de cana-de-acucar. Os residuos foram tratados para que obtivessem 12% de umidade e uma granulometria inferior a 1,70 mm. Foram produzidos 15 briquetes para cada um dos quatro tratamentos. A pressao utilizada foi de 1250 kgf.cm -2 durante 30 segundos. Os briquetes obtiveram densidades que oscilaram 0,88 a 1,11 g.cm -3 . Isto representou uma faixa de 5 a 14 vezes a menos de ocupacao de volume para uma mesma quantidade de massa. O poder calorifico foi de 19.180 J.kg -1 e 20.315 J.kg -1 para as serragens de eucalipto e pinus respectivamente. Para o bagaco e palha de cana os valores foram de 18.541 J.kg -1 e 15.628 J.kg -1 . A palha da cana-de-acucar apresentou um teor de cinzas de 12%. As expansoes dos tratamentos oscilaram 4 a 9% e as resistencias mecânicas variaram de 1,215 MPa a 0,270 MPa. Todos os briquetes se mostraram resistentes para um empilhamento superior a 10 m de altura. O procedimento adotado pode ajudar a diminuir o espaco de estocagem e de transporte. Abstract This research aims to characterize the production of briquettes from four different biomasses. We used residues such as Eucalyptus sp sawdust, Pinus sp sawdust , sugarcane bagasse ( Saccharum officinarum L.) and sugarcane straw. The residues were treated to obtain 12% moisture content and particle size less than 1.70 mm. We produced 15 briquettes for each treatment. The pressure used was 1250 kgf.cm -2 for 30 seconds. The briquettes obtained densities ranged from 0.88 to 1.11 g.cm -3 . This represented a range of 5 to 14 times less volume occupancy for the same amount of mass. The high heating value (HHV) was 19,180 J.kg -1 and 20,315 J.kg -1 for eucalyptus and pine sawdust respectively. The HHV for the bagasse was 18,541 J.kg -1 and for straw was 15,628 J.kg -1 . The straw presented an ash content of 12%. The expansions of the treatments ranged 4 to 9% and mechanical resistances ranging from 1,215 MPa to 0,270 MPa. All briquettes were resistant to a higher stacking to 10 m high. The methods can help to decrease the space of storage and transport. Keywords : Waste; biofuel; energy; compression; stacking.
Adaptive waveform design in random stepped frequency radar

Random stepped frequency (RSF) radar, whose carrier frequencies randomly hop pulse by pulse, improves the range-Doppler ambiguity and produces excellent electronic counter-countermeasures (ECCM) ability. Sparse Recovery technique improves the sensing performance of RSF radar by exploiting the sparsity of the observed targets. In this paper, a cognitive mechanism is implemented to further enhance the RSF radar. The transmitted waveforms, i.e. frequency-hopping codes, are adaptively designed to coordinate with the targets. We choose to minimize the Cramer-Rao bound on sparse recovery errors as the waveform-design criterion, and devise two corresponding algorithms. Simulations are performed, whose results demonstrate that the proposed cognitive mechanism introduces significant improvements on the performance of targets recovery. (5 pages)
Research of Generated Power Forecasting Model Based on the Fusion of Elman NN and ACOA for Photovoltaic System

A new generated power forecasting model based on the fusion of Elman neural networks (Elman NN) and ant colony optimization algorithm (ACOA) for photovoltaic system are presented in this paper. Elman NN owns stronger dynamic performance and calculation ability. And it can characterize complicated dynamics behavior. ACOA was used to optimize to improve the generalization performance of Elman NN model. The testing results show that new approaches can improve effectively the precision of generated power forecasting.
Using the WCM for transient modeling of water distribution networks

Recent water quality studies have emphasized the need for transient analysis of large pipe networks to properly assess the potential level of intrusion associated with negative pressure and the resulting effect on disinfectant residual efficiency. Transient analysis is computationally demanding even for simple pipe systems, and the computational effort for large pipe networks can be substantially high. Moreover, computational effort and accuracy of solution are interdependent. Therefore, understanding the computational efficiency and the accuracy of solution associated with the available transient analysis methods is essential for efficient handling of transients in large pipe distribution networks. This research investigated the numerical accuracy of solution and the computational efficiency of two popular methods for transient analysis—the wave characteristic method (WCM) and the method of characteristics—and elucidated their implications for practical applications. The authors offer a guideline for selecting the number of friction orifices for the WCM. In addition, this research demonstrated the superior performance of the WCM in both numerical accuracy of solution and computational effort for transient analysis of large water distribution networks.
Free Boundary Conditions for Simulating Air Movement in a Big Hall Induced by a "Bare Cabin" Fire

Air movement in a big hall induced by a fire in a "bare cabin" was simulated using Computational Fluid Dynamics (CFD). Applying CFD in simulat ing fire-induced air flow in buildings would require specification of free boundary conditions. Improper description of the free boundary conditions would give very different results. Three free boundary conditions commonly used were tested. Three sets of big hall geometry including two bare cabin designs and five heat re lease rates of fire of 20 kW m-1, 40 kW m -1, 60 kW m-1, 80 kW m-1, and 100 kW m-1 were considered. The self-developed program CY-TEAM modified from TEAM was selected as the simulator. Further, the commercial software CFX4.2 was used to compare with part of the results predicted by CY-TEAM. This gave a total number of 60 simulations. Results predicted from all these different geometries, conditions and software were compared. It is concluded that the free boundary condition should be specified carefully in simulating fire-induced air flow with CFD.
A mobile robot controller using reinforcement learning under scLTL specifications with uncertainties

The control of a mobile robot is a well‐studied problem in robotics that can be solved easily when performing simple tasks without uncertainties. However, uncertainties always exist when a mobile robot performs a series of tasks in the real‐world. In this paper, we proposed a reinforcement learning (RL)‐based controller for a mobile robot to perform a task with uncertainties. We consider the case where a task consists of several subtasks described by syntactically co‐safe linear temporal logic (scLTL) specifications and each scLTL specification is transformed into a finite state automaton (FSA) that accepts all behavior satisfying the scLTL specification. A reinforcement learning with an FSA‐encoder (RLwF) method is proposed to learn an optimal control policy in performing tasks in an environment with uncertainties. We propose an RL‐based control method with uncertainties to learn rapidly an optimal policy against the uncertainties such as jammers that prevent a mobile robot from performing specified tasks. By simulation, we demonstrate that the proposed controller can learn an optimal policy and generate an optimal path to perform the designed tasks.
Integration of GPS and Strapdown Inertial Subsystems into a Single Unit

Most GPS receivers are designed for stand-alone operation. Single-channel, slow-sequencing receivers are recognized to be lowest cost, but lack dynamic capability, while multiplexed and multichannel designs allow operation during acceleration, but add cost, weight and power. It is also well recognized that a marriage of GPS data with strapdown inertial data enhances the quality of both, and many people are looking at integration of available GPS receivers with various available inertial systems. However, direct design at the outset of a tightly integrated GPS and strapdown INS allows optimization of both for performance and cost. Using this approach, a properly designed slow-sequencing, single-channel receiver, married to a low-cost strapdown inertial unit, provides satellite tracking during 10-g acceleration, very high jamming suppression, improved strapdown inertial outputs, and improved GPS navigation accuracy. Packaging this “GPS/I” in a single unit reduces software and hardware redundancies, and results in a very low-cost design.
Power electronics in renewable energy smart grid: a review

Extensive manipulation of new power electronics technologies in renewable energy is predictable to grant efficiency improvements in smart grid evolution. This paper explores possible relationships between power electronics converters and renewable energy in smart grid. The generated power output from renewable energy is generally difficult to control, a power electronics converters capable of implementing high-speed and high-accuracy control is needed for the mass adoption of renewable energy in smart grid. Photovoltaic and wind energy are selected to be analysed as two main types of renewable energy used in smart grid. A smart grid will allow connectivity of the photovoltaic and wind turbines as intermittent sources of energy. Using photovoltaic and wind turbines with power electronics converters and enhanced control techniques can support a grid with reactive power and protect the equipment during severe grid disturbances are important issues to be addressed.
Low field electron and hole mobility of SOI transistors fabricated on ultrathin silicon films for deep submicrometer technology application

In this paper, we present a comprehensive experimental characterization of electron and hole effective mobility (/spl mu//sub eff/) of ultrathin SOI n- and p-MOSFETs. Measurements have been performed at different temperatures using a special test structure able to circumvent parasitic resistance effects. Our results indicate that, at large inversion densities (N/sub inv/), the mobility of ultrathin SOI transistors is largely insensitive to silicon thickness (T/sub SI/) and is larger than in heavily doped bulk MOS because of a lower effective field. At small N/sub inv/, instead, mobility of SOI transistors exhibits a systematic reduction with decreasing T/sub SI/. The possible explanation for this /spl mu//sub eff/ degradation in extremely thin silicon layers is discussed by means of a comparison to previously published experimental data and theoretical calculations. Our analysis suggests a significant role is played by an enhancement of phonon scattering due to carrier confinement in the thinnest semiconductor films. The experimental mobility data have then been used to study the possible implications for ultrashort SOI transistor performance using numerical simulations.
From Toad to Frog, a CT-Based Reconsideration of Bufo servatus, an Eocene Anuran Mummy from Quercy (France)

ABSTRACT In the 19th century, natural mummies of amphibians were discovered in the Quercy Phosphorites. The specific collection site was never formally reported, which hampers precise dating of these specimens. Still, the name Bufo servatus was erected based on the external morphology of one of the mummified specimens. A tomography of a similarly preserved specimen revealed a preserved skeleton, soft tissues and gut contents. We analyze here the holotype of Bufo servatus using CT-scanning in order to investigate its potentially preserved internal features. Like the previous specimen, a subcomplete articulated skeleton was identified in the B. servatus holotype. Surprisingly, this skeleton is almost identical to that of Thaumastosaurus gezei, an Eocene anuran from Western Europe to which other specimens from this mummy series were previously assigned. The few differences between the specimen skeletons highlight ontogenetic and intraspecific variations, making T. gezei a junior synonym of B. servatus and creating the new combination Thaumastosaurus servatus. Given its association with previously described Quercy specimens, this redescribed anuran is probably from the same time interval as T. gezei. Previous phylogenetic analyses assigned T. servatus to Ranoides, with natatanuran affinities. Using data from this newly described specimen, we tested here further its taxonomic affinities. Our analyses confirm this position, and formally identify T. servatus as a Natatanuran member of Pyxicephalidae (currently endemic of equatorial Africa) and more precisely, a stem-Pyxicephalinae. This result confirms the origin of Thaumastosaurus, a member of the African herpetofauna occupying Western Europe before the Grande Coupure at the Eocene/Oligocene transition.