Mining frequent sequences using itemset-based extension

In this paper, we systematically explore an itemset-based extension approach for generating candidate sequence which contributes to a better and more straightforward search space traversal performance than traditional item-based extension approach. Based on this candidate generation approach, we present FINDER, a novel algorithm for discovering the set of all frequent sequences. FINDER is composed oftwo separated steps. In the first step, all frequent itemsets are discovered and we can get great benefit from existing efficient itemset mining algorithms. In the second step, all frequent sequcnces with at least two frequent itemsets are detected by combining depth-first search and item set-based extension candidate generation together. A vertical bitmap data representation is adopted for rapidly support counting reason. Several pruning strategies are used to reduce the search space and minimize cost of computation. An extensive set ofexperiments demonstrate the effectiveness and the linear scalability of proposed algorithm

Study on the Evolution Mechanism of Lane Change Decision in Urban Expressway Diversion Area

Urban expressway is the artery of modern urban traffic network, and the vehicle operation at off-ramp and diverging area affects the operation efficiency of the whole traffic system. The lane-changing game behavior between off ramp vehicles and going straight vehicles is very important in the whole driving behavior, and the lane-changing behavior between vehicles is easy to cause traffic accidents and stopping phenomena. To improve the driving efficiency in the diversion area and reduce the accident risk, by analyzing the process of the lane-changing behavior at off-ramp, this paper establishes a two-vehicle game model, solves the replicator dynamic equation according to the Dynamic Evolutionary Game Theory, uses MATLAB to calculate the evolution process and evolution speed based on different payoff factors, explores the influence of safety and speed on the stability of turn-out, and judges the evolutionary equilibrium point according to the determinant and trail of the Jacobi matrix. We build a realistic turn-out scenario and simulate it using the micro-traffic simulation software SUMO and it is found that: (1) The speed of different evolutionary equilibrium points based on speed payoff increased by 8.3% and 4.4% respectively compared with the speed of initial point. (2) The number of conflicts at the evolutionary equilibrium point based on the security payoff reduced to 22% of the initial point. (3) Compared with the initial point, the speed of the evolutionary stable point based on comprehensive payoff increased by 10.3%, and the number of conflicts reduced to 11% of the initial point. The simulation results show that the strategy of stable point of the evolutionary game model can effectively reduce the accident rate and improve the road operation efficiency

Application of edem software to potato harvesting machinery trials

In order to intuitively analyse the role of the potato soil separation device on the material and the screening principle of the lifting chain with rod, the potato harvester is simulated and analysed using the EDEM method, and the EDEM software can get rid of the limitations of the natural environment, intuitively and quickly analyse the screening capacity of the potato harvester, reduce the cost of the research and development of agricultural equipment, and improve the efficiency

Edem simulation analysis of jammed special hole punched row tupe tigernut seeder

Through the use of EDEM simulation software, the establishment of the tigernut particle model and the card position special hole punch row tigernut precision seeder model, simulation analysis, to verify the seeding performance of the seeder

Exploration of the current status of research on tigernut seeders in China

Domestic tigernut mechanised seeding is currently in the beginning of the rapid development stage, part of the region in the reference to the original agricultural mechanisation of high-end technology on the basis of research and development were applied to the characteristics of the region relatively mature tigernut seeding machinery, but due to the regional differences are large, the related equipment is not a strong wide range of applicability

Comparative simulation analysis based on edemrecurdyn coupling

In order to verify the effectiveness of the three-stage potato soil separation device, a comparative simulation should be carried out using the EDEM-Recurdyn simulation method. The results showed that the design of the three-stage potato soil separation unit could reduce damage to potato tubers

An inverse dynamics method for railway vehicle systems

The wheel–rail action will obviously be increased during the vehicles in high-speed operation state. However, in many practical cases, direct measurement of the wheel–rail contact forces cannot be performed with traditional procedures and transducers. An inverse mathematical dynamic model for the estimation of wheel–rail contact forces from measured accelerations was developed. The inverse model is a non-iteration recurrence method to identify the time history of input excitation based on the dynamic programming equation. Furthermore, the method overcomes the weakness of large fluctuations which exist in current inverse techniques. Based on the inverse dynamic model, a high-speed vehicle multibody model with twenty-seven Degree of Freedoms (DOFs) is established. With the measured responses as input, the inverse vehicle model can not only identify the responses in other parts of vehicle, but also identify the vertical and lateral wheel–rail forces respectively. Results from the inverse model were compared with experiment data. In a more complex operating condition, the inverse model was also compared with results from simulations calculated by SIMPACK. First published online: 22 May 201

Development status of potato harvester in China

A late start has slowed the development of potato harvesters in China. Although research and development by companies such as MENOW and Hongzhu have raised the level of equipment in this field, problems remain

Characterization of OAZ1 and its potential functions in goose follicular development

Background: Ornithine decarboxylase antizyme 1 (OAZ1) is an important regulator of polyamine synthesis and uptake. Our previous studies indicated that high OAZ1 expression in the ovaries of laying geese is responsible for poor egg production. In the present study, the molecular characterization of goose OAZ1 gene was analyzed, as well as the expression profile in various follicular tissues. Results: An 873-bp cDNA sequence of the OAZ1 gene (Accession No. KC845302) with a +1 frameshift site (+175T) was obtained. The sequence consisted of a 652-bp two overlapping open reading frames (a putative protein with 216 amino acids). The OAZ domain, OAZ signature and OAZ super family domain were prominent conserved regions among species. As the follicle size increased, OAZ1 abundance showed an increasing trend during follicular development, while it decreased during follicular regression. The level of OAZ1 mRNA expression was the lowest in the fifth largest preovulatory follicle, and was 0.65-fold compared to the small white follicle (P < 0.05). OAZ1 mRNA expression in the largest preovulatory and postovulatory follicle was 2.11- and 2.49-fold compared to the small white follicle, respectively (P < 0.05). Conclusions: The goose OAZ1 structure confirms that OAZ1 plays an important role in ornithine decarboxylase-mediated regulation of polyamine homeostasis. Our findings provide an evidence for a potential function of OAZ1 in follicular development, ovulation and regression