An Improved Robot Path Planning Algorithm

Robot path planning is a NP problem. Traditionaloptimization methods are not very effective to solve it. Traditional genetic algorithm trapped into the local minimum easily. Therefore, based on a simple genetic algorithm and combine the base ideology of orthogonal design method then applied it to the population initialization, using the intergenerational elite mechanism, as well as the introduction of adaptive local search operator to prevent trapped into the local minimum and improvethe convergence speed to form a new genetic algorithm. Through the series of numerical experiments, the new algorithm has been proved to be efficiency.We also use the proposed algorithm to solve the robot path planning problem and the experiment results indicated that the new algorithm is efficiency for solving the robot path planning problems and the best path usually can be found

On the nonlinear three dimensional instability of Stokes layers and other shear layers to pairs of oblique waves

The nonlinear evolution of a pair of initially oblique waves in a high Reynolds Number Stokes layer is studied. Attention is focused on times when disturbances of amplitude epsilon have O(epsilon(exp 1/3)R) growth rates, where R is the Reynolds number. The development of a pair of oblique waves is then controlled by nonlinear critical-layer effects. Viscous effects are included by studying the distinguished scaling epsilon = O(R(exp -1)). This leads to a complicated modification of the kernel function in the integro-differential amplitude equation. When viscosity is not too large, solutions to the amplitude equation develop a finite-time singularity, indicating that an explosive growth can be introduced by nonlinear effects; we suggest that such explosive growth can lead to the bursts observed in experiments. Increasing the importance of viscosity generally delays the occurrence of the finite-time singularity, and sufficiently large viscosity may lead to the disturbance decaying exponentially. For the special case when the streamwise and spanwise wavenumbers are equal, the solution can evolve into a periodic oscillation. A link between the unsteady critical-layer approach to high-Reynolds-number flow instability, and the wave vortex approach is identified

Low-frequency sound radiated by a nonlinearly modulated wavepacket of helical modes on a subsonic circular jet

International audienceA possible fundamental physical mechanism by which instability modes generate sound waves in subsonic jets is presented in the present paper. It involves a wavepacket of a pair of helical instability modes with nearly the same frequencies but opposite azimuthal wavenumbers. As the wavepacket undergoes simultaneous spatialtemporal development in a circular jet, the mutual interaction between the helical modes generates a strong three-dimensional, slowly modulating mean-flow distortion. It is demonstrated that this mean field radiates sound waves to the far field. The emitted sound is of very low frequency, with characteristic time and length scales being comparable with those of the envelope of the wavepacket, which acts as a non-compact source. A matched-asymptotic-expansion approach is used to determine, in a self-consistent manner, the acoustic field in terms of the envelope of the wavepacket and a transfer factor characterizing the refraction effect of the background base flow. For realistic jet spreading rates, the nonlinear development of the wavepacket is found to be influenced simultaneously by non-parallelism and non-equilibrium effects, and so a composite modulation equation including both effects is constructed in order to describe the entire growthattenuationdecay cycle. Parametric studies pertaining to relevant experimental conditions indicate that the acoustic field is characterized by a single-lobed directivity pattern beamed at an angle about 4560 to the jet axis and a broadband spectrum centred at a Strouhal number St 0.070.2. As the nonlinear effect increases, the radiation becomes more efficient and the noise spectrum broadens, but the gross features of the acoustic field remain robust, and are broadly in agreement with experimental observations. © 2009 Copyright Cambridge University Press

FakeSwarm: Improving Fake News Detection with Swarming Characteristics

The proliferation of fake news poses a serious threat to society, as it can misinform and manipulate the public, erode trust in institutions, and undermine democratic processes. To address this issue, we present FakeSwarm, a fake news identification system that leverages the swarming characteristics of fake news. To extract the swarm behavior, we propose a novel concept of fake news swarming characteristics and design three types of swarm features, including principal component analysis, metric representation, and position encoding. We evaluate our system on a public dataset and demonstrate the effectiveness of incorporating swarm features in fake news identification, achieving an f1-score and accuracy of over 97% by combining all three types of swarm features. Furthermore, we design an online learning pipeline based on the hypothesis of the temporal distribution pattern of fake news emergence, validated on a topic with early emerging fake news and a shortage of text samples, showing that swarm features can significantly improve recall rates in such cases. Our work provides a new perspective and approach to fake news detection and highlights the importance of considering swarming characteristics in detecting fake news.Comment: 9th International Conference on Data Mining and Applications (DMA 2023). Keywords: Fake News Detection, Metric Learning, Clustering, Dimensionality Reductio

Direct Aerobic Carbonylation of C(sp2)-H and C(sp3)-H Bonds through Ni/Cu Synergistic Catalysis with DMF as the CO Source

The direct carbonylation of aromatic sp2 and unactivated sp3 C–H bonds of amides was achieved via nickel/copper catalysis under atmospheric O2 with the assistance of a bidentate directing group. The sp2 C–H functionalization showed high regioselectivity and good functional group compatibility. The sp3 C–H functionalization showed high site-selectivity by favoring the C–H bonds of α-methyl groups over those of the α-methylene, β- or γ-methyl groups. Moreover, this reaction showed a predominant preference for functionalizing the α-methyl over α-phenyl group. Mechanistic studies revealed that nickel/copper synergistic catalysis is involved in this process

BotShape: A Novel Social Bots Detection Approach via Behavioral Patterns

An essential topic in online social network security is how to accurately detect bot accounts and relieve their harmful impacts (e.g., misinformation, rumor, and spam) on genuine users. Based on a real-world data set, we construct behavioral sequences from raw event logs. After extracting critical characteristics from behavioral time series, we observe differences between bots and genuine users and similar patterns among bot accounts. We present a novel social bot detection system BotShape, to automatically catch behavioral sequences and characteristics as features for classifiers to detect bots. We evaluate the detection performance of our system in ground-truth instances, showing an average accuracy of 98.52% and an average f1-score of 96.65% on various types of classifiers. After comparing it with other research, we conclude that BotShape is a novel approach to profiling an account, which could improve performance for most methods by providing significant behavioral features.Comment: CDKP 202

Ureteric Obstruction Caused by a Migrated Intrauterine Device

AbstractWe present an extremely rare case of ureteric obstruction caused by a migrated intrauterine device. A 36-year-old female with complaints of almost 10 months left flank pain presented to our hospital. She used an IUD for contraception for 6 months after the birth of her first child. The IUD was not visible then. Ultrasonography (US) revealed that left severe hydronephrosis and upper ureterectasis. Pelvic computed tomography (CT) found that IUD was located very close to the lower ureter which was adjacent to the third anatomize physiological narrow. Laparoscopy was performed to remove the migrated IUD. After 5 months of surgery, left hydronephrosis was exacerbated. This time we chose to perform the ureterocystostomy to relieve the hydronephrosis. We reported this rare case to remind that we must keep alert to the loss of the IUD to prevent it may cause severe injury of the nearby organs. IUD must be carefully researched for possible perforation of the uterus and migration to the pelvic organs