2,313 research outputs found
A Flexible Electronic Helical Guide Controller
AbstractIn this paper, an Electronic Helical Guide Controller (EHGC) is proposed, for helical gear shaping processes. In most traditional gear shaper machines, the cutter's reciprocating movement is driven by a crank-connecting rod mechanism. Therefore, this study adopts this kind of gear shaper as the machine platform to establish an accurate mathematical model. The control algorithm is embedded in the interpolation module of the CNC system using electronic gearbox techniques to realize special multi-axis linkage control requirements. The crankshaft's angular position is measured and the rotational speed is calculated in each control cycle. The actual position and velocity of the cutter along the Z-axis can be calculated using the geometric relations of the crank-connecting mechanism, and motion in the other axes can be controlled by the electronic gearbox. A special G code with parameters (G83) is also designed and the EHGC control through NC programming is realized in an improvised gear shaping CNC machine. The proposed EHGC is low cost and easy to implement in practice since it does not need a linear grating ruler and a probe on the Z-axis. Furthermore, EHGC allows the flexibility to change a part's helix angle to compensate for distortions caused by heat treatment. Simulations and experiments are performed to verify the effectiveness of the proposed EHGC
Multi-party quantum private comparison of size relationship with two third parties based on d-dimensional Bell states
In this paper, we put forward a multi-party quantum private comparison (MQPC)
protocol with two semi-honest third parties (TPs) by adopting d-dimensional
Bell states, which can judge the size relationship of private integers from
more than two users within one execution of protocol. Each TP is permitted to
misbehave on her own but cannot collude with others. In the proposed MQPC
protocol, TPs are only required to apply d-dimensional single-particle
measurements rather than d-dimensional Bell state measurements. There are no
quantum entanglement swapping and unitary operations required in the proposed
MQPC protocol. The security analysis validates that the proposed MQPC protocol
can resist both the outside attacks and the participant attacks. The proposed
MQPC protocol is adaptive for the case that users want to compare the size
relationship of their private integers under the control of two supervisors.
Furthermore, the proposed MQPC protocol can be used in the strange user
environment, because there are not any communication and pre-shared key between
each pair of users.Comment: 15 pages, 1 figure, 1 tabl
The ideal response of a Gulf of Mexico estuary plume to wind forcing: Its connection with salt flux and a Lagrangian view
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95390/1/jgrc11924.pd
Study on Complex Products Job-shop Scheduling System Based on MES
Various random disturbances that happen in the process of complex products (ship) production cannot feedback timely, and the plans of job-shop operation are too rough to instruct job-shop production. The purpose of this study is to solve the problems above, help the course of complex products (ship) job-shop production runs orderly and efficiently, and improve the job-shop on-site management level. In this paper, we proposed complex products job-shop scheduling system based on MES. The system adopts six-level, refined plan and scheduling mechanism. Its key part is the job-shop scheduling model with man-machine coordinated mechanism. What’s more, an improved Genetic Algorithm based on TOC is proposed to make the optimized algorithm module of the system more scientific and effective. Key words: Complex Products; MES; Job-shop Scheduling System; Man-machine Coordinated Mechanism; Genetic Algorithm Résumé: Diverses perturbations qui se produisent au hasard dans le processus de production des produits complexes (navire) ne peuvent pas être apperçues en temps opportun, et les plans de l'opération des ateliers sont trop approximatifs pour guider la production. Le but de cette étude consiste à résoudre les problèmes ci-dessus, rendre le cours de la production des produits complexes (ship) dans les ateliers ordonné et efficace et améliorer le niveau de gestion sur place. Dans cet article, nous avons proposé le système de planning des ateliers de produits complexes basé sur MES. Le système contient six niveaux de programmation raffinée et de mécanismes de planning. Son élément essentiel est le modèle de programmation avec les mécanismes de coordination homme-machine. De plus, un algorithme génétique amélioré basé sur TOC est également proposé de rendre le module de l'algorithme du système optimisé plus scientifique et efficace. Mots-clés: produits complexes; MES; système de planning des ateliers; mécanismes de coordination homme-machine; algorithme génétique 摘要:針對目前複雜產品(船舶)生產過程中所出現的各種隨機擾動不能得到及時回饋,以及車間作業計畫粗略難以直接指導車間生產的現狀,本文提出基於 MES的複雜產品車間作業調度系統。該系統採用逐層細化的五級計畫與調度機制,以人機協同的車間作業調度模型為核心,通過改進基於 TOC的遺傳演算法,使系統的演算法模組優化性能更具有科學性和操作性。該系統有助於實現複雜產品(船舶)車間生產過程的有序運作,從而提高生產車間的現場管理水準。 關鍵字:複雜產品; MES;車間作業調度;人機協同;遺傳演算
Research on BOM Mapping transformation for Ship Construction Process
Abstract: Due to the problem about the core departmental "information isolated island" with BOM, various stages of ship product design section are convergence off and impeded the construction of agile ship the product. In this paper, first, establish the various stages of the ship product BOM structure model, based on a comparison of the structural model analysis, design a more practical conversion method, and then describe the conversion process about the ship product life cycle BOM view in order to quickly build a variety of BOM view.
Keywords: BOM; BOM tectonic model; BOM view of conversio
Measurement report: The promotion of low-level jet and thermal-effect on development of deep convective boundary layer at the southern edge of the Taklimakan Desert
A vigorous development process of the deep convective boundary layer (CBL) was observed at the southern edge of the Taklimakan Desert on 6 June, 2022. Based on coherent Doppler wind lidar and ERA5 data, the formation mechanism of the deep CBL exceeding 5 km was well analyzed, which was mainly promoted by the low-level jet (LLJ) and thermal-effect. The LLJ has made sufficient momentum, energy and material preparations for the development of the deep CBL. Firstly, the cold downhill airflow of the Tibet Plateau leading to LLJ weakens the height and intensity of the temperature inversion layer, which reduces the energy demand for the broken of the IL. Secondly, the LLJ not only supplements the material and energy in the residual layer, but also suppresses the exchange with the lower atmosphere. In addition, the LLJ provides a driving force for the development of the deep CBL. In terms of thermal factors, the Tibet Plateau sensible heat driven air-pump and cold front transit provide additional impetus for the development of the deep CBL. Finally, the formation of deep CBL was catalyzed by the extreme thermal effects of the underlying surface, such as the furnace effect and the atmospheric superadiabatic expansion process. The study of the development of the deep CBL is important for revealing the land-air exchange process of momentum, energy, and material between the Taklimakan Desert and the Tibetan Plateau
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