Reachable Range Research Articles

Attitude Practical Stabilization of Underactuated Autonomous Underwater Vehicles in Vertical Plane

Due to the singularity of Euler angles and the ambiguity of quaternions, to further expand the attitude reachable range of underactuated AUVs in the vertical plane, SO(3) is used to represent the attitude change of underactuated AUVs. The transverse function of the attitude on SO(3) is designed, and the exponential mapping method is used to construct the attitude kinematic controller of underactuated AUVs. Considering the changes in the model and ocean current during motion, interval type II fuzzy systems (IT2-FLSs) are used to estimate these changes. The backstepping method and the small gain theorem are adopted to design dynamic controllers to ensure the stability and robustness of the system. A novel saturation auxiliary system is designed to compensate for the influence of actuator saturation characteristics. Finally, the simulation results verify the effectiveness of the proposed controller and ensure the practical stabilization of the underactuated AUV attitude.

Transoral Robotic-Assisted Neurosurgery for Skull Base and Upper Spine Lesions.

The application of the da Vinci Surgical System in neurosurgery is limited due to technical difficulties requiring precise maneuvers and small instruments. This study details the advantages and disadvantages of robotics in neurosurgery and the reachable range of the transoral approach to lesions of the skull base and upper cervical spine. In a cadaver study, the da Vinci Xi robot, lacking haptic feedback, was utilized for sagittal and coronal approaches on 5 heads, facilitating dura suturing in 3, with a 30°-angled drill for bone removal. Perfect exposure of all the nasopharyngeal sites, clivus, sellar, and choana, including the bilateral eustachian tubes, was achieved without any external incisions using this palatal split approach of transoral robotic surgery. The time required to perform a single stitch, knot, and complete single suture in robotic suturing of deep-seated were significantly less compared to manual suturing via the endonasal approach. This is the first report to show the feasibility of suturing the dural defect in deep-seated lesions transorally and revealed that the limit of reach in the coronal plane via a transoral approach with incision of the soft palate is the foramen ovale. This preclinical investigation also showed that the transoral robotic approach is feasible for lesions extending from the sellar to the C2 in the sagittal plane. Refinement of robotic instruments for specific anatomic sites and future neurosurgical studies are needed to further demonstrate the feasibility and effectiveness of this system in treating benign and malignant skull base lesions.

Elderly-friendly indoor vertical dimensional layout method based on joint mobility.

The vertical dimensional arrangement of space is primarily influenced by the reachable range of human fingertips. Currently, this dimensional layout analysis concentrates solely on static body dimensions based on Farley's principle. However, the joint mobility of the elderly population has diminished, necessitating the identification of the factors influencing the age-friendly spatial vertical dimension layout through experimentation. A random sample of 62 adults and 62 elderly individuals were selected to measure the joint mobility of 8 groups with varying comfort levels. The measurement results were analyzed using an independent sample t-test with SPSS software. The joint mobility of the elderly group exhibited a notable difference from that of the adult group across distinct comfort gradients. A significant reduction in the range of motion of all joints in the elderly was observed. The findings suggest that the reachable range of the upper limbs of the elderly should be considered in conjunction with joint mobility. We propose a vertical dimensional layout method for residential spaces that accommodates the joint mobility of elderly users. The joint mobility of the elderly is significantly deteriorating, and the traditional vertical spatial layout method cannot adequately support the daily life of the elderly. It is essential to integrate the joint mobility factor into the vertical dimensional layout design process. In this paper, we propose an elderly-friendly vertical spatial dimension layout method. It offers a reference for subsequent planning of elderly-friendly vertical dimension layout.

An Improved Direct Predictive Torque Control for Torque Ripple and Copper Loss Reduction in SRM Drive

This paper introduces a direct predictive torque control (DPTC) method to minimize the torque ripple and copper loss of the switched reluctance motor (SRM). Generally, there is a problem with torque ripple during the SRM’s commutation. In this method, the commutation optimization is provided by a direct predictive torque control algorithm. Firstly, the reachable range of phase torques is predicted and the boundary of two continuous phases is modified. By dividing the torque range directly to determine the torque allocation set, the suppression of torque ripple becomes simple. Secondly, considering the optimization problem of copper loss during commutation, a cost function only related to the phase current is constructed. Further, the minimization of copper loss can be achieved by solving the cost function, and the work of setting weight parameters is not required. Finally, the proposed DPTC method is tested by simulation and experiment in a three-phase 12/8-pole SRM drive system and the results are compared with the existing predictive torque control methods. The results show that the proposed method has less torque ripple and copper loss, which effectively improves the torque control performance.

A Comprehensive Study of Bluetooth Low Energy

Bluetooth Low Energy (BLE) is an innovative technique that was firstly employed in Bluetooth 4.0 and is being applied in the Bluetooth 5.0 and 5.2 technologies. Bluetooth 5.0 and 5.2 technologies are now widely used in all kinds of electronic communication equipment (e.g., PCs, tablets, smartphones, wearable devices). BLE has the capacity to minimize the power consumption and equipment cost in the low-power devices, which becomes a competitive scheme among the huge number of standard wireless transmission techniques already existing in everyday life for a large number of applications. As one of the available solutions in wireless transmission, Bluetooth technology equipped with the BLE module is very suitable for developing internet of things (IoTs) technology, which is gaining more and more interest. This paper briefly introduces the modulation and encoding of the BLE standard in the physical layer (PHY). The applications of cyclic redundancy check (CRC) in BLE are then presented. Moreover, the main characteristics, including the maximum reachable range, transmission latency, and power consumption of BLE, are also introduced.

Towards Sustainable Cities: Utilizing Floating Car Data to Support Location-Based Road Network Performance Measurements

Road network performance (RNP) is a key element for urban sustainability as it has a significant impact on economy, environment, and society. Poor RNP can lead to traffic congestion, which can lead to higher transportation costs, more pollution and health issues regarding the urban population. To evaluate the effects of the RNP, the involved stakeholders need a real-world data base to work with. This paper develops a data collection approach to enable location-based RNP analysis using publicly available traffic information. Therefore, we use reachable range requests implemented by navigation service providers to retrieve travel times, travel speeds, and traffic conditions. To demonstrate the practicability of the proposed methodology, a comparison of four German cities is made, considering the network characteristics with respect to detours, infrastructure, and traffic congestion. The results are combined with cost rates to compare the economical dimension of sustainability of the chosen cities. Our results show that digitization eases the assessment of traffic data and that a combination of several indicators must be considered depending on the relevant sustainability dimension decisions are made from.

PD07-02 INITIAL EVALUATION OF NOVEL FLEXIBLE URETEROSCOPE WITH OMNI-DIRECTIONAL BENDING USING JOYSTICK UNIT (URF-Y0016); IN EX-VIVO RESEARCH

INTRODUCTION AND OBJECTIVE: The accessible range of a lower pole calyx according to retrograde ureteral access using a flexible ureteroscope with the usual two deflected directions is often limited. We developed and evaluated a flexible ureteroscope with omni-directional bending using a joystick unit (URF-Y0016). METHODS: The URF-Y0016 possesses the features of omni-directional bending in the tip of a flexible ureteroscope, which is integrated by four deflected directions and the controlling element of a handgun type with a joystick unit. We compared the accessible range of the URF-Y0016 with the URF-P6 (Olympus, Japan) by using a three-dimensional (3D) pyelocaliceal model ex vivo. The 3D pyelocaliceal model was constructed by upper, middle, and lower pole calyces (Fig. 1-A). Each inside of the calyx dome was distributed d the index of reachable angle by a 10-degree interval in eight directions (Fig. 1-B,C). Four experts of stone surgery evaluated the accessible range of the eight directions in each calyx between the URF-Y0016 and URF-P6. RESULTS: The URF-Y0016 can reached a significantly broader range in the lower pole calyx than that of the URF-P6 (p=0.002) (Fig. 2). In particular, the 0 and 1:30 o’clock directions in the anterior, and the 6 and 7:30 o’clock directions in the inferior parts in all eight directions in the lower pole calyx were significantly different between the URF-Y0016 and URF-P6 (48.8 degrees vs 13.8 degrees, p=0.003; 42.5 degrees vs 17.5 degrees, p=0.001; 53.8 degrees vs 11.3 degrees, p=0.003; and 66.3 degrees vs 11.3 degrees, p=0.001, respectively). However, the reachable range in the upper pole and middle pole calyces were not significantly different between the URF-Y0016 and URF-P6 (p=0.446 and p=0.295). CONCLUSIONS: The URF-Y0016 is a novel flexible ureteroscope with omni-directional bending. This ureteroscope may have great potential for easily reaching the lower pole calyx, especially the anterior and inferior lower pole calyces, in clinical practice.Source of Funding: none

Control Strategy Based on Model Reduction and Online Intelligent Calculation for Planar $n$ -Link Underactuated Manipulators

This paper presents a control strategy based on model reduction and online intelligent calculation for a planar ${n}$ -link underactuated manipulator with a passive first joint (PA $^{{n-1}}$ for short) to realize its control objective, which is to move its end-point from an initial position to a target position. First, two active links of the planar PA $^{{n-1}}$ manipulator are chosen to be the active links of a planar virtual passive–active–active (PAA) manipulator, which guarantees that the geometric reachable range of the planar virtual PAA manipulator is the same as that of the planar PA $^{{n-1}}$ manipulator. The planar PA $^{{n-1}}$ manipulator is reduced to the planar virtual PAA manipulator by keeping the states of two active links in their initial values and controlling the states of the remaining ${n-3}$ active links to zero. Then, the planar virtual PAA manipulator is equivalent to two planar virtual Acrobots by adopting two-stage control method. Based on two sets of angle constraint relationships corresponding to two planar virtual Acrobots, an online differential evolution algorithm is employed to obtain all link target angles of the planar virtual PAA manipulator. Next, two Lyapunov functions, each of which is constructed based on the active link angle of one planar virtual Acrobot, are used to design controllers to realize the system control objective. Finally, Simulation results of a planar PAA-active manipulator demonstrate the effectiveness of the proposed control strategy.

Influence of the Elemental Composition, Density, and Enthalpy of Formation of Solid Fuel Dispersants on the Range of an Atmospheric Aircraft

About 50 fuel formulations based on boron, hydrocarbon binder, and high-enthalpy polynitrogen dispersant were considered. The quantitative dependence of the reachable aircraft range with the optimized fuels on the elemental composition of the dispersant, its enthalpy of formation, and density was examined. The quantitative dependences of the aircraft range on the content of each element constituting the dispersant were obtained, and differences in these quantities were accounted for. Empirical formulas relating the flight range to the above characteristics of the dispersant were obtained; they allow prediction of the ballistic performance of the dispersants (including compounds that have not been synthesized by now) with an error no higher than 1%.

New scheme of SHE-PWM technique for cascaded multilevel inverters with regulation of DC voltage sources

In this paper the Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) technique with considering controllable DC link voltages is implemented in the cascaded multilevel inverter. The novelty of this work is the method of mathematical modelling of SHE-PWM with respect to variable voltage of DC links. With respect to variable voltage of DC links, the number of degrees of freedom are increased compared to ordinary SHE techniques with constant voltage of DC links. One of the issues in SHE-PWM technique is solution of nonlinear equations under various operating conditions of the converter. In the proposed formulation, the resulted nonlinear equations are solved only one time for entire reachable range of output voltage amplitude, which leads to considerable reduction of computational burden. Also, the THD of output voltage waveform remains constant at minimum value for different operating points. The theoretical results of proposed technique are verified by the simulation and scale-down experimental setup of a cascaded 7-level inverter.

Delay sensitive data routing optimization using rendezvous agents in wireless sensor networks with mobile sink

The method of data collection and transmission of delay sensitive data often relies on mobile sink in wireless sensor networks. This is either by transmitting directly to the mobile sink if the mobile sink is in the reachable range of the sensor that is intended to send the data, or by using the route established by the hop level sensors between the sensors that are intended to send the data and the mobile sink. The constraint of this strategy can portray as the energy consumption due to the suboptimal methods of routing between source sensor and mobile sink and the fault intolerance in data collection and transmission sequence. Hence, it is obvious to conclude that the significant contributions required about the design of optimal data collection and transmitting strategies for energy efficient and fault tolerant delay sensitive data transmission in wireless sensor networks with mobile sink. According to the context of these objectives stated, this manuscript portrayed a ‘Delay Sensitive Data Routing Optimization using Rendezvous Agents’ for energy efficient and fault tolerant delay sensitive data transmission in wireless sensor networks with mobile sink. The significance of the proposal was evaluated by experimental study using network simulation. Performance of the proposal is scaled by comparing the proposed model with the other contemporary model built under similar objectives. The traditional metrics are in use to compare and scale the performance of the proposal with the contemporary model.

Risk factors of clinical mastitis and antimicrobial susceptibility test results of mastitis milk from dairy cattle in western Thailand: Bayesian network analysis

Using Bayesian network analysis, this cross-sectional study aimed to identify the conditional probability among dairy farm practices, cow characteristics, bacteriological culture results, and antimicrobial susceptibility test results of milk from dairy cows with clinical mastitis in western Thailand. Data associated with risk factors and clinical signs were collected using a structured questionnaire that was administered to 34 small dairy holders. In total, 100 quarters of milk samples from 100 cows were used for Bayesian network analysis. Conditional probability results showed that the following variables had the highest probabilities relevant to the occurrence of clinical mastitis pathogens: parity, concrete and rubber floor, hand stripping after using machine milking, dry cow therapy, and routine cleaning of milking machines. These variables were associated with the first four highest posterior probabilities of the occurrence of Streptococcus spp. (16.68%; reachable range or the minimum and maximum posterior probability values for the occurrence of Streptococcus spp., 15.45%–17.91%), Staphylococcus spp. (11.87%; reachable range, 11.06%–12.67%), Escherichia coli (7.53%; reachable range, 6.95%–8.17%), and Streptococcus dysgalactiae (7.28%; reachable range, 6.73%–7.83%), which were the most frequently isolated pathogens. Conditional probability results indicated these pathogens were most sensitive to amoxicillin/clavulanic acid (80.58%) and cloxacillin (64.28%). Most pathogens were resistant to penicillin G (40.37%). In this study, Bayesian network analysis revealed several clinically significant risk factors of mastitis associated with various pathogens and farming characteristics. Simple statistics could not provide sufficient information for the successful control of mastitis. In contrast, through in-depth data analysis, Bayesian networks could identify risk factors in various situations, hence providing information that will be crucial to help farmers reduce the cost of farming.

Gaia-DR2 extended kinematical maps

Context. The Gaia Collaboration has used Gaia-DR2 sources with six-dimensional (6D) phase space information to derive kinematical maps within 5 kpc of the Sun, which is a reachable range for stars with relative error in distance lower than 20%. Aims. Here we aim to extend the range of distances by a factor of two to three, thus adding the range of Galactocentric distances between 13 kpc and 20 kpc to the previous maps, with their corresponding error and root mean square values. Methods. We make use of the whole sample of stars of Gaia-DR2 including radial velocity measurements, which consists in more than seven million sources, and we apply a statistical deconvolution of the parallax errors based on the Lucy’s inversion method of the Fredholm integral equations of the first kind, without assuming any prior. Results. The new extended maps provide lots of new and corroborated information about the disk kinematics: significant departures of circularity in the mean orbits with radial Galactocentric velocities between −20 and +20 km s−1 and vertical velocities between −10 and +10 km s−1; variations of the azimuthal velocity with position; asymmetries between the northern and the southern Galactic hemispheres, especially towards the anticenter that includes a larger azimuthal velocity in the south; and others. Conclusions. These extended kinematical maps can be used to investigate the different dynamical models of our Galaxy, and we will present our own analyses in the forthcoming second part of this paper. At present, it is evident that the Milky Way is far from a simple stationary configuration in rotational equilibrium, but is characterized by streaming motions in all velocity components with conspicuous velocity gradients.

Steady-Sensitivity Distributed Acoustic Sensors

Distributed acoustic sensors (DAS) based on phase-sensitive optical time-domain reflectometry (ϕOTDR) have demonstrated interesting performance for many applications ranging from seismology to pipeline protection. However, the sensitivity of traditional DAS relying on coherent detection is strongly dependent on the system noise and trace fading points, offering poor reliability of the results in the spatial dimension. In this manuscript, we evaluate the statistical performance of a recently proposed DAS technique, namely, chirped-pulse ϕOTDR, in terms of sensitivity and signal-to-noise ratio (SNR). Our results show behavioral trends that significantly differ from those of traditional DAS. In particular, the acoustic SNR distribution in chirped-pulse DAS is notably narrower than that in the traditional case, allowing to ensure a large system dynamic range across all the points of the optical trace. Hence, chirped-pulse ϕOTDR offers localized perturbation detection with very high reliability, almost independent of trace fading points, along the complete reachable range of the sensor.

Performance Evaluation of Bluetooth Low Energy: A Systematic Review.

Small, compact and embedded sensors are a pervasive technology in everyday life for a wide number of applications (e.g., wearable devices, domotics, e-health systems, etc.). In this context, wireless transmission plays a key role, and among available solutions, Bluetooth Low Energy (BLE) is gaining more and more popularity. BLE merges together good performance, low-energy consumption and widespread diffusion. The aim of this work is to review the main methodologies adopted to investigate BLE performance. The first part of this review is an in-depth description of the protocol, highlighting the main characteristics and implementation details. The second part reviews the state of the art on BLE characteristics and performance. In particular, we analyze throughput, maximum number of connectable sensors, power consumption, latency and maximum reachable range, with the aim to identify what are the current limits of BLE technology. The main results can be resumed as follows: throughput may theoretically reach the limit of ~230 kbps, but actual applications analyzed in this review show throughputs limited to ~100 kbps; the maximum reachable range is strictly dependent on the radio power, and it goes up to a few tens of meters; the maximum number of nodes in the network depends on connection parameters, on the network architecture and specific device characteristics, but it is usually lower than 10; power consumption and latency are largely modeled and analyzed and are strictly dependent on a huge number of parameters. Most of these characteristics are based on analytical models, but there is a need for rigorous experimental evaluations to understand the actual limits.

Interface Design Optimization by an Improved Operating Model for College Students

A method was proposed in this study for assessing the interface operating efficiency of a remote control. The operating efficiency of a product interface can be determined by the proposed approach in which the related dimensions of human palms were measured. The reachable range (blue zone) and the most comfortable range (green zone) were investigated when a user used a single hand (right hand) to operate the remote controls. After that, new remote control designs were created based on the measurement results and the operating efficiency of commercially available remote controls were determined for comparison. The operating efficiency is determined by calculating the overall distance of finger movements when manipulating the buttons and the overall operation time was recorded. The subjects who joined the body measurements and performed the experiments are right-hander Asian college students between the ages of 22 and 28. After further optimization, the reachable range became more average during one-handed operations and those frequently used keys were included into the comfortable range. The resulting operating efficiency performance is higher than commercially available products. The results serve as a good reference for detailed modifications of the products or for the decision making of design proposals.

Creating equally spaced linear ion string in a surface-electrode trap by feedback control

A feedback control method for producing an equidistant ion string in a surface-electrode ion trap has been experimentally demonstrated. This method features three advantages: (i) The optimal voltage can be constrained within the specified reachable range. (ii) The height of trapped ions from the trap surface can be maintained at the same value when strings with different number of ions or with different ion spacings are to be trapped. (iii) This method is resistant to a stray electric field near the trap. By this method, the asymmetry of the ion string caused by a stray field is minimized. The robustness of trapping a variable number of ions at the same potential and the dependency of the axial frequency on the number of ions are also investigated experimentally. This work would be a practical method to create a linear ion string with a large number of ions and may find applications in large-scale quantum computing, quantum simulation, and phase transition studies utilizing homogeneous ion strings.

Keyhole approach in the neuroendoscopic treatment for hydrocephalus.

The aim of the study was to explore keyhole approach and dura suture in the neuroendoscopic treatment for hydrocephalus.Twelve cases of hydrocephalus patients who were treated with neuroendoscope by this approach were analyzed retrospectively from April 2015 to April 2016 in our department. The basic steps of this procedure was using drill and milling cutter to form a small bone flap instead of burr hole, and then making a cruciate incision on the dura. After endoscopic third ventriculostomy or endoscopic third ventriculostomy + ventriculocystostomy finished, dura was sutured and the bone flap was reset.All 12 patients could suture dura effectively, and no cerebrospinal fluid leak and subcutaneous cerebrospinal fluid collection happened; symptoms of hydrocephalus were also improved. Moreover, during the operation, we found this approach could suspend dura, and avoid the cerebral sulcus and cortical coarse vein effectively, which could reduce the risk of intracranial hemorrhage. In addition, we found this approach could increase the reachable range of the neuroendoscope significantly.Keyhole approach can suture dura and avoid the cerebral sulcus and cortical coarse vein effectively, increase the indications, and reduce complications of neuroendoscope. So, this approach has clinical values and can be used in hydrocephalus.

Model Predictive Control considering Reachable Range of Wheels for Leg / Wheel Mobile Robots

Obstacle avoidance is one of the important tasks for mobile robots. In this paper, we study obstacle avoidance control for mobile robots equipped with four legs comprised of three DoF SCARA leg/wheel mechanism, which enables the robot to change its shape adapting to environments. Our previous method achieves obstacle avoidance by model predictive control (MPC) considering obstacle size and lateral wheel positions. However, this method does not ensure existence of joint angles which achieves reference wheel positions calculated by MPC. In this study, we propose a model predictive control considering reachable mobile ranges of wheels positions by combining multiple linear constraints, where each reachable mobile range is approximated as a convex trapezoid. Thus, we achieve to formulate a MPC as a quadratic problem with linear constraints for nonlinear problem of longitudinal and lateral wheel position control. By optimization of MPC, the reference wheel positions are calculated, while each joint angle is determined by inverse kinematics. Considering reachable mobile ranges explicitly, the optimal joint angles are calculated, which enables wheels to reach the reference wheel positions. We verify its advantages by comparing the proposed method with the previous method through numerical simulations.

Maximizing Range Sum in External Memory

This article studies the MaxRS problem in spatial databases. Given a set O of weighted points and a rectangle r of a given size, the goal of the MaxRS problem is to find a location of r such that the sum of the weights of all the points covered by r is maximized. This problem is useful in many location-based services such as finding the best place for a new franchise store with a limited delivery range and finding the hotspot with the largest number of nearby attractions for a tourist with a limited reachable range. However, the problem has been studied mainly in the theoretical perspective, particularly in computational geometry. The existing algorithms from the computational geometry community are in-memory algorithms that do not guarantee the scalability. In this article, we propose a scalable external-memory algorithm ( ExactMaxRS ) for the MaxRS problem that is optimal in terms of the I/O complexity. In addition, we propose an approximation algorithm ( ApproxMaxCRS ) for the MaxCRS problem that is a circle version of the MaxRS problem. We prove the correctness and optimality of the ExactMaxRS algorithm along with the approximation bound of the ApproxMaxCRS algorithm. Furthermore, motivated by the fact that all the existing solutions simply assume that there is no tied area for the best location, we extend the MaxRS problem to a more fundamental problem, namely AllMaxRS , so that all the locations with the same best score can be retrieved. We first prove that the AllMaxRS problem cannot be trivially solved by applying the techniques for the MaxRS problem. Then we propose an output-sensitive external-memory algorithm ( TwoPhaseMaxRS ) that gives the exact solution for the AllMaxRS problem through two phases. Also, we prove both the soundness and completeness of the result returned from TwoPhaseMaxRS. From extensive experimental results, we show that ExactMaxRS and ApproxMaxCRS are several orders of magnitude faster than methods adapted from existing algorithms, the approximation bound in practice is much better than the theoretical bound of ApproxMaxCRS, and TwoPhaseMaxRS is not only much faster but also more robust than the straightforward extension of ExactMaxRS.