•Lumbopelvic distance reduction enhances stability after total sacrectomy.•Lumbopelvic distance reduction lowers the bone-implant and rod stress.•All reconstruction techniques are suitable for ...lumbopelvic stabilization.•Regardless of the used technique, LPDR is biomechanically advantageous.
Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet.
To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR.
A comparative finite element (FE) study.
The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods.
Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR<SRR<FRR<CLR, with ICR being the stiffest for both parameters. LPDR decreased the shift-down displacement values by 25% in CLR, by 61% in SRR, by 15% in FRR, and by 46% in ICR, as well as reduced the relative sagittal rotation values by 21% in CLR, by 73% in SRR, by 11% in FRR, and by 53% in ICR. Considering the stress at the bone-implant interface, without LPDR, the ICR yielded the smallest stress values for flexion, lateral bending, and axial rotation with 131.4 MPa, 68.2 MPa, and 70.3 MPa, respectively, and the second smallest in extension with 36.1 MPa. Due to LPDR, these stress values were reduced by 31% in flexion, by 17% in extension, by 29% in lateral bending, and by 29% in axial rotation. Within the rods, without LPDR, the ICR yielded the smallest stress values for flexion, extension, lateral bending, and axial rotation with 346.5 MPa, 108.0 MPa, 186.2 MPa, and 199.7 MPa, respectively. With LPDR, these stress values were reduced by 16% in flexion, by 9% in extension, by 11% in lateral bending, and by 12% in axial rotation.
LPDR significantly improved both lumbopelvic stability and implant safety in all reconstruction techniques after total sacrectomy. LPDR reduced the shift-down displacement of L5, the relative sagittal rotation of L5, and the stress values at the bone-implant interface. Furthermore, in the ICR and SRR techniques, LPDR decreased the peak stress values within the rods. All four investigated LPRTs demonstrated suitability for lumbopelvic reconstruction, with the ICR technique exhibiting the highest lumbopelvic stiffness.
LPDR creates a biomechanically advantageous environment following total sacrectomy; therefore, it has the potential to impact the design of custom-made 3D-printed or traditional LPRTs. However, to confirm the findings of the current FE study, long-term clinical trials are recommended.
This study presents a new multi-objective Taguchi approach for optimal integration of distributed generations (DGs) in small and large scale distribution networks. The Taguchi method (TM) is a ...statistical method and employs orthogonal arrays (OAs) to estimate the output response in less number of computations. In every cycle, OA is updated according to mean response of each parameter at its respective levels in the previous cycle. A new node priority list is proposed to guide TM to select promising nodes. For multi-objective problems, a trade-off is developed between various objectives using the technique for order of preference by similarity to ideal solution that reduces Euclidean distances of various objectives from their best solutions and increases Euclidean distances from their worst solutions. A multi-objective DG integration problem is formulated to demonstrate the applicability of the proposed approach and tested on IEEE 33-bus, 118-bus and a practical 201-bus radial distribution systems. The simulation results are compared with existing multi-objective optimisation techniques used for optimal DG integration problems in the literature and found to be promising.
The need to decrease unit production costs has led agricultural industries to develop larger and consequently heavier machinery. While this has increased the productivity of single machines, it has ...also caused significant soil compaction, which may cause reduced crop yield and crop quality. Therefore, mechanisation solutions that have both lower unit costs and reduce the risk of soil compaction are needed. Optimising infield routes will reduce labour costs, fuel consumption and field trafficking intensity, providing important benefits for infield operations. In this paper, a prototype of an optimised infield route planning tool for neutral material flow operations is evaluated. The evaluation parameters focused on distance and traffic intensity reductions, comparing the routes proposed by the tool prototype and the routes followed by a professional operator during mowing operations. The tool requires some minimum inputs: field boundaries, field gates, working width and minimum turning radius, in order to provide an optimised route. Twelve fields were recorded by a Global Positioning System (GPS) during mowing operations and later compared with the routes proposed by the tool. In all fields, the operator's normal route was longer in distance than the route proposed by the tool, being up to 18.4% longer. In total, 9.2 km of infield distance was saved, i.e. 7.5%. The traffic intensity was reduced in all fields, except for two of the smallest fields, where it equalled that of the normal route. Specifically, the traffic intensity was reduced in the working areas, as the tool confined all non-working distance to the headlands.
•Tests during mowing comparing traversed distances and traffic intensity.•Optimised Infield Route Planner (ORP) produced optimised routes for all case fields.•Routes recorded by operator 0.2%–18.4% longer than the optimised routes.•Traffic intensity was either reduced or equal for all twelve fields.•ORP tool also limited the amount of traffic in the working area of the field.
Owing to the extensive growth of wireless technology for sending and collecting a variety of information for the different applications, routing is a major challenge to find the optimal path for the ...data transmission. In this study, the authors have developed a new algorithm called, exponential ant colony optimisation (EACO) to route discovery problem in wireless sensor network after finding the cluster heads (CHs) using fractional artificial bee colony (FABC) algorithm. In the first step, CHs are found out using the FABC algorithm with fitness function considering the distance, energy and delay. In the second phase, ACO algorithm is modified with exponential smoothing model for multi‐path route discovery. This new algorithm called, EACO found the optimal routes among CHs to transmit a data from any source node to base station with multiple objectives including energy, distance, intra‐cluster delay and intercluster delay. These objectives are effectively formulated as new fitness function to find the optimal route path. From the experimentation, the outcome showed that the cumulative energy kept after 2000 round of experiments is 0.2039 for the proposed algorithm but the existing approach (threshold + ACO) kept only 0.0338.
The charge plasma-based tunnel field-effect transistor (TFET) has been seen as the potential candidate to replace the conventional TFET as it offers fabrication simplicity and its proficiency to be ...used for ultra-low-power applications. A charge plasma TFET (CPTFET) with hetero materials for enhancement of device performance is presented. For this, a narrow bandgap material (InAs) is used instead of silicon in source region for reducing the lateral tunnelling distance at the source/channel interface. The reduced tunnelling width at the source/channel junction enables higher band-to-band tunnelling generation rate, thus the device offers higher ON-state current. In this context, a comparative study of CPTFET and hetero junction charge plasma TFET (H-CPTFET) has been performed in terms of transfer characteristic (Ids–Vgs), transconductance (gm), gate-to-drain capacitance (Cgd), cut-off frequency (fT) and gain-bandwidth product. In addition to this, the effect of variation in channel length (Lg) and drain to source voltage (Vds) on the DC and analogue/radio frequency performance of H-CPTFET is also analysed.
In this paper, we focus on a generalized multi-user distributed antenna system (DAS), where the antenna elements (AEs) are divided into antenna clusters and the antenna clusters are randomly deployed ...in the coverage area. The mobile terminals equipped with
M
AEs each are supposed to be uniformly distributed in the coverage area. We are motivated to study the impact of the deployment of antenna elements on the system performance. In the model of consideration, the deployment of antenna elements is characterized by the antenna cluster size
V
, i.e., the number of AEs within each antenna cluster, and the distribution of the antenna clusters. With the assumption that the antenna clusters are uniformly deployed in the coverage area, the impact of the antenna cluster size
V
on the uplink sum rate capacity is particularly investigated. The mean square access distance (MSAD), a function of
V
, is proposed as a reasonable metric instead of the uplink sum rate capacity. From the analysis of the asymptotic behavior of MSAD, we derive an approximate closed-form expression for the expectation of MSAD over system topologies. Then, it is concluded that the ergodic uplink sum rate capacity can be improved due to access distance reduction by scattering AEs further only when
V
>
M
. An approximate closed-form expression for the relative variance of MSAD is also derived. And we conclude that the outage uplink sum rate capacity can be improved due to macro-diversity by scattering AEs further only when
V
≤
M
. In other words, when
V
≤
M
, the ergodic uplink sum rate capacity can not be improved by scattering AEs further, when
V
>
M
, the outage uplink sum rate capacity can not be improved by scattering AEs further. Finally, our analysis is well verified by Monte Carlo simulations.
In our study of cognitive dissonance 59 students adjusted their physical proximity with an opposing other to manage dissonance. Participants wrote a counterattitudinal essay (vs. proattitudinal), ...then each of them was told he/she had to discuss the topic with another student who was
against the current topic (vs. in favor of). While the experimenter allegedly fetched the other student the participant set up the room by installing 2 chairs. The distance between the 2 chairs was used to measure the proximity with the other. The results showed that in the dissonance condition
participants set greater physical proximity when the other disagreed with their initial attitude and less physical proximity when the other was supportive of their initial attitude. We suggest further research is conducted to confirm the use of proximity as a means of dissonance reduction.
We present a cognitive, connectionist-based model of complex problem solving that integrates cognitive biases and distance-based and environmental rewards under a temporal-difference learning ...mechanism. The model is tested against experimental data obtained in a well-defined and planning-intensive problem. We show that incorporating cognitive biases (symmetry and simplicity) in a temporal-difference learning rule (SARSA) increases model adequacy—the solution space explored by biased models better fits observed human solutions. While learning from explicit rewards alone is intrinsically slow, adding distance-based rewards, a measure of closeness to goal, to the learning rule significantly accelerates learning. Finally, the model correctly predicts that explicit rewards have little impact on problem solvers’ ability to discover optimal solutions.
► We present a temporal-difference-based model of human problem solving. ► The model includes distance-based rewards (DBR), a measure of closeness to goal. ► With DBR, environmental rewards are not necessary for learning the task. ► Incorporating cognitive biases (symmetry and simplicity) increases model adequacy.
Ultra-wideband (UWB) communication is an emerging technology that enables secure ranging and localization. Since UWB communication enables measuring an exact distance, enhanced security would be ...expected based on it. Recently, however, it has been demonstrated that a distance measured by IEEE 802.15.4z high-rate pulse repetition frequency (HRP) UWB ranging system can be maliciously reduced. The HRP UWB ranging system is widely adopted by smartphone manufacturers such as Samsung and Apple.
In this paper, we present UWB with sub-template verification (UWB-SV), which is the first method that prevents a practical distance reduction attack on the current HRP UWB ranging system. UWB-SV is designed to act as a verification method, in which the scrambled timestamp sequence (STS) field of a UWB frame is divided into multiple sub-fields. By analyzing the consistency of the cross-correlation results between the sub-fields and their corresponding local templates, UWB-SV is able to detect a distance reduction attack on the HRP UWB ranging system. Since a long bit sequence is not required for a consistency analysis, UWB-SV can be applied to most commercial off-the-shelf devices that are designed with a 4,096-bit length of the STS field. We comprehensively evaluate UWB-SV under 16 different channel conditions between the victim and attacker, through which we show that UWB-SV has an attack detection rate of 96.24% in outdoor environment conditions with a false positive rate of 0.32%.
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