Random Collisions Research Articles

Throughput and latency in the distributed Q-learning random access mMTC networks

In mMTC mode, where thousands of devices try to access network resources sporadically, the problem of random access (RA) and collisions between devices that select the same resources arise. A promising approach to solve the RA problem is the use of learning mechanisms, specially Q-learning (QL) algorithm, where the devices learn about the best time-slot periods to transmit through rewards sent by the central node. In this work, we propose a distributed packet-based learning method of varying the reward given by the central node that favors devices having a larger number of remaining packets to transmit. The numerical results indicated that the proposed distributed packet-based QL method attains a better throughput–latency trade-off than the independent and collaborative techniques in practical scenarios, while the number of payload bits of the packet-based technique is reduced regarding the collaborative QL RA technique for achieving the same normalized throughput.

A Study on Bearing Dynamic Features under the Condition of Multiball–Cage Collision

Cage stability directly affects the dynamic performance of rolling bearing, which, in turn, affects the operating state of rotating equipment. The random collision between the rolling elements and the cage pocket is the main reason for cage instability. In this paper, from the perspective of the relative sliding velocity between the rolling elements and the bearing raceway, the interactions of the rolling elements and the cage pockets were analyzed, and the four zones with different collision features were defined. On this basis, and on the basis of the bearing dynamics model, the interaction of two adjacent rolling elements and the cage pockets in the a’–b’ area is discussed, and the peak impact force of the adjacent two balls and the cage pockets was investigated in terms of the rotation speed, radial load, acceleration/deceleration, and materials. When the ball runs close to the loaded zone, the probability of multiball random collision increases, which leads to an increase in the cage instability. At the entrance of the loaded zone, the peak impact force has the greatest impact on the cage stability during the acceleration process. Compared to the radial load applied to the bearing, the peak impact force is more sensitive to the bearing speed changes. The multiball collision analysis method provides a new idea for the research of cage stability.

DESIGN AND EXPERIMENT OF THE SEED DELIVERY DEVICE WITH A ROTATING BRUSH WHEEL FOR PRECISION SEEDER

In high speed seeding operation, the random collisions of seeds in the seed delivery tube seriously affect the seeding accuracy. In order to improve seeding uniformity and stability in high speed operation, the seed delivery device with a rotating brush wheel was designed, including U-shaped groove seed tube and flexible brush wheel. The optimization experiment was carried out by quadratic-regression rotatable orthogonal design method in JPS-12 seeding performance test bench. The three main factors were the rotate speed of seed metering device, the brush wheel diameter and the brush wheel speed. The evaluation indexes were the qualified rate of seeding spacing, miss seeding rate and coefficient of variation of seeding spacing. The results showed that the optimal parameters were rotate speed of seed metering device of 30 r/min, brush wheel diameter of 66 mm and brush wheel speed of 850 r/min. Finally, the verification experiment was carried out. The test results showed that the working performance of seed delivery device with a rotating brush wheel was obviously better than that of common seed delivery tube, especially at the forward speed of 15 km/h and above. The research provides a reference for the innovative design for a high speed precision seeder.

The spatial association of accessory minerals with biotite in granitic rocks from the South Mountain Batholith, Nova Scotia, Canada

Abstract We use mineral liberation analysis (MLA) to quantify the spatial association of 15,118 grains of accessory apatite, monazite, xenotime, and zircon with essential biotite, and clustered with themselves, in a peraluminous biotite granodiorite from the South Mountain Batholith in Nova Scotia (Canada). A random distribution of accessory minerals demands that the proportion of accessory minerals in contact with biotite is identical to the proportion of biotite in the rock, and the binary touching factor (percentage of accessory mineral touching biotite divided by modal proportion of biotite) would be ~1.00. Instead, the mean binary touching factors for the four accessory minerals in relation to biotite are: apatite (5.06 for 11,168 grains), monazite (4.68 for 857 grains), xenotime (4.36 for 217 grains), and zircon (5.05 for 2876 grains). Shared perimeter factors give similar values. Accessory mineral grains that straddle biotite grain boundaries are larger than completely locked, or completely liberated, accessory grains. Only apatite-monazite clusters are significantly more abundant than expected for random distribution. The high, and statistically significant, binary touching factors and shared perimeter factors suggest a strong physical or chemical control on their spatial association. We evaluate random collisions in magma (synneusis), heterogeneous nucleation processes, induced nucleation in passively enriched boundary layers, and induced nucleation in actively enriched boundary layers to explain the significant touching factors. All processes operate during the crystallization history of the magma, but induced nucleation in passively and actively enriched boundary layers are most likely to explain the strong spatial association of phosphate accessories and zircon with biotite. In addition, at least some of the apatite and zircon may also enter the granitic magma as inclusions in grains of Ostwald-ripened xenocrystic biotite.

Role of particle dynamics in processing of terrestrial nitrogen and phosphorus in the estuarine mixing zone

AbstractMultiple biogeochemical processes in estuaries modulate the flux of nutrients from land to sea, thus contributing to the coastal filter. The role of particle dynamics in regulating the fate of terrestrial nutrients in estuaries is poorly constrained. To address this issue, we resolved the particle size distribution of suspended material, and quantified size‐fractionated particulate nitrogen (PN) and phosphorus (PP), in a stratified mesotrophic estuary (Pojoviken, Finland). We also carried out a mixing experiment where the effects of salt‐induced flocculation on particle size distribution and concentrations of PN and PP were examined. The experimental results showed that salt‐induced flocculation at already very low salinities increases the total particle concentration and mean particle size, indicating transfer of dissolved material into particulates. Correspondingly, a significant increase in PP and particulate iron (Fe) was observed in the experiment results, suggesting coupled flocculation of P‐containing organic matter (OM) and ferrihydrite. Particle dynamics in the field data were dominated by processes occurring downstream of the flocculation zone. Primary production created a downward flux of autochthonous OM particles, promoting passive aggregation by random collisions with terrestrial material in the water column. Maximum particle concentrations were observed at and below the halocline. The highest PN and PP concentrations were observed in the subhalocline layer, 3.5 and 0.14 μmol L−1, respectively. Molar ratios of N:P in this material were >40, consistent with typical marine snow in the early stages of microbial processing. Our study provides a mechanistic overview of the biogeochemical drivers of particulate nutrient dynamics in stratified estuarine environments.

Multi-Sequence Spreading Random Access (MSRA) for Compressive Sensing-Based Grant-Free Communication

The performance of grant-free random access (GF-RA) is limited by the number of accessible random access resources (RRs) due to the absence of collision resolution. Compressive sensing (CS)-based RA schemes scale up the RRs at the expense of increased non-orthogonality among transmitted signals. This paper presents the design of multi-sequence spreading random access (MSRA) which employs multiple spreading sequences to spread the different symbols of a user as opposed to the conventional schemes in which a user employs the same spreading sequence for each symbol. We show that MSRA provides code diversity, enabling the multi-user detection (MUD) to be modeled into a well-conditioned multiple measurement vectors (MMVs) CS problem. The code diversity is quantified by the decrease in the average Babel mutual coherence among the spreading sequences. Moreover, we present a two-stage active user detection (AUD) scheme for both wideband and narrowband implementations. Our theoretical analysis shows that with MSRA activity misdetection falls exponentially while the size of GF-RA frame is increased. Finally, the simulation results show that about 82% increase in utilization of RRs, i.e., more active users, is supported by MSRA than the conventional schemes while achieving the RA failure rate lower bound set by random access collision.

A Theoretical Analysis of Magnetic Particle Alignment in External Magnetic Fields Affected by Viscosity and Brownian Motion

The interaction of an external magnetic field with magnetic objects affects their response and is a fundamental property for many biomedical applications, including magnetic resonance and particle imaging, electromagnetic hyperthermia, and magnetic targeting and separation. Magnetic alignment and relaxation are widely studied in the context of these applications. In this study, we theoretically investigate the alignment dynamics of a rotational magnetic particle as an inverse process to Brownian relaxation. The selected external magnetic flux density ranges from 5μT to 5T. We found that the viscous torque for arbitrary rotating particles with a history term due to the inertia and friction of the surrounding ambient water has a significant effect in strong magnetic fields (range 1–5T). In this range, oscillatory behavior due to the inertial torque of the particle also occurs, and the stochastic Brownian torque diminishes. In contrast, for weak fields (range 5–50μT), the history term of the viscous torque and the inertial torque can be neglected, and the stochastic Brownian torque induced by random collisions of the surrounding fluid molecules becomes dominant. These results contribute to a better understanding of the molecular mechanisms of magnetic particle alignment in external magnetic fields and have important implications in a variety of biomedical applications.

Interfacial Area Transport Equation for Bubble Coalescence and Breakup: Developments and Comparisons.

Bubble coalescence and breakup play important roles in physical-chemical processes and bubbles are treated in two groups in the interfacial area transport equation (IATE). This paper presents a review of IATE for bubble coalescence and breakup to model five bubble interaction mechanisms: bubble coalescence due to random collision, bubble coalescence due to wake entrainment, bubble breakup due to turbulent impact, bubble breakup due to shearing-off, and bubble breakup due to surface instability. In bubble coalescence, bubble size, velocity and collision frequency are dominant. In bubble breakup, the influence of viscous shear, shearing-off, and surface instability are neglected, and their corresponding theory and modelling are rare in the literature. Furthermore, combining turbulent kinetic energy and inertial force together is the best choice for the bubble breakup criterion. The reviewed one-group constitutive models include the one developed by Wu et al., Ishii and Kim, Hibiki and Ishii, Yao and Morel, and Nguyen et al. To extend the IATE prediction capability beyond bubbly flow, two-group IATE is needed and its performance is strongly dependent on the channel size and geometry. Therefore, constitutive models for two-group IATE in a three-type channel (i.e., narrow confined channel, round pipe and relatively larger pipe) are summarized. Although great progress in extending the IATE beyond churn-turbulent flow to churn-annual flow was made, there are still some issues in their modelling and experiments due to the highly distorted interface measurement. Regarded as the challenges to be addressed in the further study, some limitations of IATE general applicability and the directions for future development are highlighted.

A Background Assessable and Correctable Bimolecular Fluorescence Complementation System for Nanoscopic Single-Molecule Imaging of Intracellular Protein-Protein Interactions.

Bimolecular Fluorescence Complementation (BiFC) is a versatile approach for intracellular analysis of protein-protein interactions (PPIs), but the tendency of the split fluorescent protein (FP) fragments to self-assemble when brought into close proximity of each other by random collision can lead to generation of false-positive signals that hamper high-definition imaging of PPIs occurring on the nanoscopic level. While it is thought that expressing the fusion proteins at a low level can remove false positives without impacting specific signals, there has been no effective strategy to test this possibility. Here, we present a system capable of assessing and removing BiFC false positives, termed Background Assessable and Correctable-BiFC (BAC-BiFC), in which one of the split FP fragments is fused with an optically distinct FP that serves as a reference marker, and the single-cell fluorescence ratio of the BiFC signal to the reference signal is used to gauge an optimal transfection condition. We showed that when BAC-BiFC is designed to image PPIs regulating Human Immunodeficiency Virus type 1 (HIV-1) assembly, the fluorescence ratio could decrease with decreasing probe quantity, and ratios approaching the limit of detection could allow physiologically relevant characterization of the assembly process on the nanoscale by single-molecule localization microscopy (SMLM). With much improved clarity, previously undescribed features of HIV-1 assembly were revealed.

Threshold concentration and random collision determine the growth of the huntingtin inclusion from a stable core

The processes underlying formation and growth of unfolded protein inclusions are relevant to neurodegenerative diseases but poorly characterized in living cells. In S. cerevisiae, inclusions formed by mutant huntingtin (mHtt) have some characteristics of biomolecular condensates but the physical nature and growth mechanisms of inclusion bodies remain unclear. We have probed the relationship between concentration and inclusion growth in vivo and find that growth of mHtt inclusions in living cells is triggered at a cytoplasmic threshold concentration, while reduction in cytoplasmic mHtt causes inclusions to shrink. The growth rate is consistent with incorporation of new material through collision and coalescence. A small remnant of the inclusion is relatively long-lasting, suggesting that it contains a core that is structurally distinct, and which may serve to nucleate it. These observations support a model in which aggregative particles are incorporated by random collision into a phase-separated condensate composed of a particle-rich mixture.

Rate control for therapeutic applications in Internet of Bio-Nano Things using molecular communication: A survey

Molecular communication is transmitting and receiving chemical signals using molecules and is an interdisciplinary field between nanotechnology, biology, and communication. Molecular communication can be used for connecting bio-nano things. The connected nano-things build a nano-network. Transport mechanisms in molecular communication include free diffusion, gap junction channels, molecular motors, self-propelling microorganisms like bacteria and random collision of mobile nano-things. Free diffusion is the most widely used transport mechanism in the literature. Brownian motion is always available and its energy consumption is zero. This paper explores the therapeutic applications of rate control in the Internet of Bio-Nano Things and reviews the recent trends and advancements in the field of molecular communication. These methods aim to guarantee the desired rate of drug molecules at the target site and overcome the side effects of excessive emission.

Ultrasensitive Detection of Amyloid β Oligomers Based on the "DD-A" FRET Binary Probes and Quadrivalent Cruciform DNA Nanostructure-Mediated Cascaded Amplifier.

The reported donor donor-acceptor ("DD-A") fluorescence resonance energy transfer (FRET) was typically achieved through random collisions and interactions of DNA molecules in the bulk solution, which has inevitable defects, including weak biological stability, slow reaction kinetics, and low hybridization efficiency. In order to overcome these deficiencies, this work developed a quadrivalent cruciform DNA nanostructure (qCDN)-mediated cascaded catalyzed hairpin assembly (CHA) amplifier for the fluorescence detection of amyloid β oligomer species (AβOs). First, four H1 and four H2 hairpins were assembled on one qCDN to obtain qCDNH1 and qCDNH2, respectively. In the presence of AβOs, strand C was released from the P1-C hybrid hairpin and then alternately opened qCDNH1 and qCDNH2 to trigger the qCDN-mediated CHA. As a result, double donors in H1 and one acceptor in H2 were mutually closed, and the porous DNA nanonet with a high loading of "DD-A" FRET binary probes was formed. The FRET efficiency was approximately 78%, and the initial reaction rate was 25-fold faster than the conventional CHA. The detection limit of AβOs was as low as 0.69 pM. The combination of the "DD-A" FRET binary probes and qCDN-mediated cascaded amplifier exhibited great promise for detecting biomarkers with trace levels.

Novel Solutions to NOMA-Based Modern Random Access for 6G-Enabled IoT

Modern random access avoids scheduling overheads and greatly improves the transmission efficiency of small packets. The major challenge is the random collision, and slotted ALOHA (SA)-based methods were proposed to cancel collisions via the receiving time slot diversity. Based on power-domain multiple access (PDMA), some nonorthogonal multiple access (NOMA) SA methods increased the active user number. This article refines PDMA-based methods at the first step, including: 1) the existing NOMA irregular repetition SA is enhanced and 2) NOMA coded SA is proposed. However, PDMA-based methods require accurate sensing and power control to separate multiple users in the power domain, which is not friendly to low-cost devices. This article proposes a NOMA SA method named spreading SA (SSA), which does not rely on any sensing or power control. Both physical and medium access control layers are considered, and the outage model, instead of the collision model, is proposed to be used for NOMA SA. SSA uses random nonorthogonal code spreading to reduce collisions as a relatively large number of codes can be employed. Compared with the power domain, the code domain gains a much higher degree of freedom. It can be utilized without any coordination with the help of blind detection technologies. Moreover, collision resolution diversity SSA (CRDSSA) is proposed to further improve the user loading. The simulation results validate the analysis and show that the proposed SSA-based methods support a higher user loading and much higher flexibility than existing NOMA SA works in most cases.

Deciphering hierarchical organization of topologically associated domains through change-point testing

BackgroundThe nucleus of eukaryotic cells spatially packages chromosomes into a hierarchical and distinct segregation that plays critical roles in maintaining transcription regulation. High-throughput methods of chromosome conformation capture, such as Hi-C, have revealed topologically associating domains (TADs) that are defined by biased chromatin interactions within them.ResultsWe introduce a novel method, HiCKey, to decipher hierarchical TAD structures in Hi-C data and compare them across samples. We first derive a generalized likelihood-ratio (GLR) test for detecting change-points in an interaction matrix that follows a negative binomial distribution or general mixture distribution. We then employ several optimal search strategies to decipher hierarchical TADs with p values calculated by the GLR test. Large-scale validations of simulation data show that HiCKey has good precision in recalling known TADs and is robust against random collisions of chromatin interactions. By applying HiCKey to Hi-C data of seven human cell lines, we identified multiple layers of TAD organization among them, but the vast majority had no more than four layers. In particular, we found that TAD boundaries are significantly enriched in active chromosomal regions compared to repressed regions.ConclusionsHiCKey is optimized for processing large matrices constructed from high-resolution Hi-C experiments. The method and theoretical result of the GLR test provide a general framework for significance testing of similar experimental chromatin interaction data that may not fully follow negative binomial distributions but rather more general mixture distributions.

Traffic Prediction and Random Access Control Optimization: Learning and Non-Learning-Based Approaches

Random access channel (RACH) procedures in modern wireless communications are generally based on multi-channel slotted-ALOHA, which can be optimized by flexibly organizing devices' transmission and retransmission. However, due to the lack of information about the traffic generation statistics and the occurrence of random collision, optimizing RACH in an exact manner is generally challenging. In this article, we first summarize the general structure of optimization for different RACH schemes, and then review existing RACH optimization methods based on machine learning (ML) and non-ML techniques. We demonstrate that the ML-based methods can better optimize RACH schemes compared to non-ML-based methods due to their capability in solving high-complexity long-term optimization problems. To further improve the RACH performance, we introduce a decoupled learning strategy (DLS) for access control optimization, which individually executes two sub-tasks: traffic prediction and access control configuration. In detail, the traffic prediction relies on an online supervised learning method adopting recurrent neural networks that can accurately capture traffic statistics over consecutive frames, while the access control configuration uses either a non-ML-based controller or a cooperatively trained deep reinforcement learning (DRL)-based controller selected depending on the complexity of different random access schemes. Numerical results show that the DLS optimizer considerably outperforms conventional DRL optimizers in terms of higher training efficiency and better access performance.

MOLECULAR MECHANISM OF ERYTHROCYTIC INVASION BY THE MEROZOITE STAGE OF Plasmodium falciparum

ABSTRACT Malaria is an ancient disease that continues to cause enormous human morbidity and mortality mainly due to the invasion of the erythrocyte by the merozoite stage of the Parasite (Plasmodium falciparum), as the parasite spend much of it life intracellularly. Therefore the aim of this paper was to review the state of knowledge on the mechanism of erythrocytic invasion by the merozoite of Plasmodium falciparum. The invasion process is a coordinated series of protein/protein interactions, protease cleavage events, intracellular signals, organelle release and engagement of an actin-myosin motor. The invasion is achieved through either, sialic acid dependent which uses EBA-140,EBA-175,EBA-181 and PfRH1 or sialic acid in-dependent pathways which uses PfRH2 and PfRH4. Successful invasion process is completed in the following steps; Meroziote activation, Merozoite binding, Reorientation and deformation, Junction formation and Parasite entry. Merozoite acitivation involve egresses of the merozite from the erythrocyte where exoneme secretes the first protein called subtisilin-like protease-1 (PfSUB-1) in to the parasitophorous vacuole which ensure primary proteolysis of Serine-Repeat antingen (SERA) which in turn act on Parasitophorous Vacoule and Red Blood Cell to initiate host cell rupture. Dipeptidyl peptidase 3 (DPAP3) also contribute to the egress by regulating the maturation of PfSUB-1. The initial interaction between the merozoite and the erythrocyte is due to random and weak collision and presumptively involves in the first instance a reversible interaction between proteins on the merozoite surface and the host erythrocyte. In this ligands bind to specific receptors on the merozoite, where Erythrocyte Binding Anitigen-175 (EBA-175) bind to Glycophorin A, EBA-140 binds to Glycophorin C, Erythrocyte Binding-like-1 protein (EBL-1) binds to Glycophorin B and PfRh4 binds to Complement Receptor-1 (CR-1) and PfRh5 binds to Basigin (CD147) on the erythrocyte. This is followed by permanent positioning of the apical organelles of the merozoite on to the red blood cell (re-orientation) and release of adhesive proteins (adhesins), Protease and membrane altering agent specifically Subtisilin-2 (PfSUB-2), Apical Membrane Antigen-1 (AMA1).Junction formation is an intimate circumferential contact with the host cell called tight junction and it is formed under the influence of Apical Membrane Antigen 1 (AMA1) and Rhoptery neck (RON). Finally the merozoite penetrates in to the erythrocyte bilayer with the help of Actin- Myosin motor, Thrombospondin-Related Anonymous Protein family (TRAP) and aldolase

Research on Bridge Structure Reliability Evaluation due to Vessels Collison Based on a Statistical Moment Method

Damage to bridge structures caused by vessel collision is a risk for bridges crossing water traffic routes. Therefore, safety around vessel collision of existing and planned bridges is one of the key technical problems that must be solved by engineering technicians and bridge managers. In the evaluation of the reliability of the bridge structure, the two aspects of vessel‐bridge collision force and structural resistance need to be considered. As there are many influencing parameters, the performance function is difficult to express by explicit function. This paper combines the moment method theory of structural reliability with finite element analysis and proposes a statistical moment method based on finite element analysis for the calculation of vessel‐bridge collision reliability, which solves the structural reliability problem with a nonlinear implicit performance function. According to the probability model based on current velocity, vessel velocity, and vessel collision tonnage, the estimate points in the standard normal space are converted into estimate points in the original state space through the Rosenblatt reverse transform. According to the estimate points in the original state space and the simplified dynamic load model of vessel‐bridge collision, the sample time‐history curve of random vessel‐bridge collision force is generated, the dynamic response of the bridge structure and the structural resistance of the bridge are calculated by establishing a finite element model, and the failure probability and reliability index of the bridge structure is calculated according to the fourth‐moment method. The statistical moment based on the finite element analysis is based on the finite element analysis and the moment method theory of structural reliability. The statistical moment of the limited performance function is calculated through a quite small amount of confirmatory finite element analysis, and the structural reliability index and failure probability are obtained. The method can be widely used in existing finite element analysis programs, greatly reducing the number of finite element analyses needed and improving the efficiency of structural reliability analysis.

Electrochemical and electrochemiluminescent behaviors of a single Nafion@Ru or Au-Nafion@Ru nanoparticle colliding onto an ultramicroelectrode

Nafion and Au-Nafion nanoparticles (NPs) are electrostatically loaded with ruthenium (II) tris(2,2’-bipyridyl) (Ru(bpy)32+) luminescent molecules to prepare Nafion@Ru and Au-Nafion@Ru NPs. The average spike current, peak charge and duration per spike of the response peaks generated by random collisions of Au-Nafion@Ru NPs and Nafion@Ru NPs on gold ultramicroelectrodes (Au UME) were analyzed and compared, and an electrochemical collision system with Au-Nafion@Ru NPs as the main body was established. The results show that the prepared Au-Nafion@Ru NPs possess the special structure of Au-Nafion@Ru, which can increase the effective contact or collision sites between NPs and Au UME with the co-participation of Nafion and AuNPs, resulting in an enhanced electrochemical collision response signal. In the system of Au-Nafion@Ru NPs-tri- n -propylamine (TPrA), the time-current curve and electrochemiluminescence (ECL)-time method were used to monitor the electrical and ECL transient signals generated by Nafion@Ru or Au-Nafion@Ru NPs colliding with Au UME, and a good relationship between electrochemical and ECL transient signals generated by the collisions of single Au-Nafion@Ru NPs-TPrA on Au UME was established. This strategy provides a new insight for studying the electrochemical collision systems of other molecules.

Motion behaviour of metallic particle under diverging conducting electrode considering the random collision and reflection

An improved model for the motion dynamics of a metallic particle located in the non-uniform electric field area in the gas insulated system is proposed. To represent the special area, a diverging conducting electrode is used in this study. Based on the fluid mechanics theory, the forces imposed on metallic particle are first developed. The motion process is then divided into two modes, i.e. the particle rolls on the electrode surface and moves in the gap. The collision and reflection processes between the particle and the electrode are crucial to the motion, and they are fully considered in the proposed model. The trajectory of the particle under different voltages is obtained. The evolution of metallic particle is divided into four stages, and it is featured by four quantities, i.e. the critical jumping point, the minimum horizontal position, the falling point, and the motion time. The characteristics for each stage are analysed, and the sensitivity analysis of the quantities are performed. The impacts of the applied voltage, the particle radius, the initial position etc. are discussed. The results provide guidance for particle trap design.

Elbow precision machining technology by abrasive flow based on direct Monte Carlo method

The investigation was carried out on the technical problems of finishing the inner surface of elbow parts and the action mechanism of particles in elbow precision machining by abrasive flow. This work was analyzed and researched by combining theory, numerical and experimental methods. The direct simulation Monte Carlo (DSMC) method and the finite element analysis method were combined to reveal the random collision of particles during the precision machining of abrasive flow. Under different inlet velocity, volume fraction and abrasive particle size, the dynamic pressure and turbulence flow energy of abrasive flow in elbow were analyzed, and the machining mechanism of particles on the wall and the influence of different machining parameters on the precision machining quality of abrasive flow were obtained. The test results show the order of the influence of different parameters on the quality of abrasive flow precision machining and establish the optimal process parameters. The results of the surface morphology before and after the precision machining of the inner surface of the elbow are discussed, and the surface roughness Ra value is reduced from 1.125 µm to 0.295 µm after the precision machining of the abrasive flow. The application of DSMC method provides special insights for the development of abrasive flow technology.