Aiming at the characteristics of obvious block division and strong discreteness in the assembly production mode of electronic products,this paper proposes a composite U-shaped flexible assembly line model,and establis...Aiming at the characteristics of obvious block division and strong discreteness in the assembly production mode of electronic products,this paper proposes a composite U-shaped flexible assembly line model,and establishes a multi-objective optimization mathematical model on this basis.According to the characteristics of the model,the improved ranked positional weight(RPW)method is used to adjust the generation process of the initial solution of the genetic algorithm,so that the genetic algorithm can be applied to the block task model.At the same time,the adaptive cross mutation factor is used on the premise that tasks between different blocks are not crossed during cross mutation,which effectively improves the probability of excellent individuals retaining.After that,the algorithm is used to iterate to obtain the optimal solution task assignment.Finally,the algorithm results are compared with actual production data,which verifies the validity and feasibility of the assembly line model for discrete production mode proposed in this paper.展开更多
Under the condition of the market competition becom in g more and more drastic, the demands of market take on some new features such as individuation, diversification, small batch, unstableness and quick delivery et c...Under the condition of the market competition becom in g more and more drastic, the demands of market take on some new features such as individuation, diversification, small batch, unstableness and quick delivery et c. The Make-to-Stock mode is usually adopted by many enterprises to improve th e balance and stableness of production process. In such enterprises, order batch , production batch and sales batch are the important factors, which affect the s atisfaction of clients, efficiency and benefit of the enterprise. It takes purch ase, production and sales into account respectively when optimizing product batc h in traditional way. However, it ignored the influences of relations between ea ch links of whole system. It is assumed that the consumption and market demand a re continuous process whereas the factual demands are batched when economic batc h is determined. So there exist some deviations between the economic batch deter mined by traditional way and that by integral optimization. Through the integral analysis of Logistics in the production system, we know that from materials are purchased, then manufactured, finally sold, the material changed in appearance and value, it still exist in different links of production system. The amount of materials occupied varies just in different status, from stock status to produc tion status, then to waiting-be-sold status, there is not any substantial chan ge in quantity until they are sold. So we must comprehensively analyze the relat ions among each link based on integral production system, to optimize the materi al batch and cut short production cycle in order to optimize the whole system. In this paper, the production system is taken as a global entity, and in which m aterials variation law and their relations of each link are analyzed; To optimiz e the whole materials flow, a new model of multi-product systems’ economic orde r batch, economic production batch and optimal sale lot multi-product syste ms’ is developed which based on the limit of capitals and stock area.展开更多
We investigate a basisity problem in the space =lpA(D)and in its invariant sub-spaces. Namely, let W denote a unilateral weighted shift operator acting in the spacelpA(D), 1≤p《∞, by W zn=λnzn+1, n≥0, with re...We investigate a basisity problem in the space =lpA(D)and in its invariant sub-spaces. Namely, let W denote a unilateral weighted shift operator acting in the spacelpA(D), 1≤p《∞, by W zn=λnzn+1, n≥0, with respect to the standard basis λzn+1 n≥0. Applying the so-called "discrete Duhamel product" technique, it is proven that for any integer k ≥1 the sequence {(wi+nk)-1|W |Ei)knf}n≥0 is a basic sequence in Ei :=span{zi+n :n≥0} equivalent to the basis {zi+n}n≥0 if and only if fb(i) 6= 0. We also investigate a Banach algebra structure for the subspaces Ei, i≥0.展开更多
Sine Non-linear Chirp Keying(SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some par...Sine Non-linear Chirp Keying(SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some parameter estimation issues over conventional modulation schemes. In this paper, a novel transform termed as Discrete Sinusoidal Frequency Modulation transform(DSFMT) is proposed. Then, the DSFMT of SNCK signal is deduced and classified into three types, based on which, the time-bandwidth product is estimated by the proposed algorithm. Simulation results show that the noise has a signifi cant impact on the localization of the peak value and the time-bandwidth product can be estimated by using local ratio values when.展开更多
3D printing has become a promising technique for industry production. This paper presents a research on the manufacturability optimization of discrete products un- der the influence of 3D printing technology. For this...3D printing has become a promising technique for industry production. This paper presents a research on the manufacturability optimization of discrete products un- der the influence of 3D printing technology. For this, we first model the problem using a tree structure, and then formulate it as a linear integer programming, where the total production time is to be minimized with the production cost constraint. To solve the problem, a differential evolution (DE) algorithm is developed, which automatically determines whether tra- ditionai manufacturing methods or 3D printing technology should be used for each part of the production. The algorithm is further quantitatively evaluated on a synthetic dataset, com- pared with the exhaustive search and alternating optimization solutions. Simulation results show that the proposed algo- rithm can well combine the traditional manufacturing meth- ods and 3D printing technology in production, which is help- ful to attain optimized product design and process planning concerning manufacture time. Therefore, it is beneficial to provide reference of the widely application and further in- dustrialization of the 3D printing technology.展开更多
A positivity-preserving, conservative and entropic numerical scheme is presented for the three-temperature grey diffusion radiation hydrodynamics model. Moreprecisely, the dissipation matrices of the colocalized semi...A positivity-preserving, conservative and entropic numerical scheme is presented for the three-temperature grey diffusion radiation hydrodynamics model. Moreprecisely, the dissipation matrices of the colocalized semi-Lagrangian scheme are de-fined in order to enforce the entropy production on each species (electron or ion) proportionally to its mass as prescribed in [34]. A reformulation of the model is then considered to enable the derivation of a robust convex combination based scheme. Thisyields the positivity-preserving property at each sub-iteration of the algorithm whilethe total energy conservation is reached at convergence. Numerous pure hydrodynamics and radiation hydrodynamics test cases are carried out to assess the accuracy of themethod. The question of the stability of the scheme is also addressed. It is observedthat the present numerical method is particularly robust.展开更多
文摘Aiming at the characteristics of obvious block division and strong discreteness in the assembly production mode of electronic products,this paper proposes a composite U-shaped flexible assembly line model,and establishes a multi-objective optimization mathematical model on this basis.According to the characteristics of the model,the improved ranked positional weight(RPW)method is used to adjust the generation process of the initial solution of the genetic algorithm,so that the genetic algorithm can be applied to the block task model.At the same time,the adaptive cross mutation factor is used on the premise that tasks between different blocks are not crossed during cross mutation,which effectively improves the probability of excellent individuals retaining.After that,the algorithm is used to iterate to obtain the optimal solution task assignment.Finally,the algorithm results are compared with actual production data,which verifies the validity and feasibility of the assembly line model for discrete production mode proposed in this paper.
文摘Under the condition of the market competition becom in g more and more drastic, the demands of market take on some new features such as individuation, diversification, small batch, unstableness and quick delivery et c. The Make-to-Stock mode is usually adopted by many enterprises to improve th e balance and stableness of production process. In such enterprises, order batch , production batch and sales batch are the important factors, which affect the s atisfaction of clients, efficiency and benefit of the enterprise. It takes purch ase, production and sales into account respectively when optimizing product batc h in traditional way. However, it ignored the influences of relations between ea ch links of whole system. It is assumed that the consumption and market demand a re continuous process whereas the factual demands are batched when economic batc h is determined. So there exist some deviations between the economic batch deter mined by traditional way and that by integral optimization. Through the integral analysis of Logistics in the production system, we know that from materials are purchased, then manufactured, finally sold, the material changed in appearance and value, it still exist in different links of production system. The amount of materials occupied varies just in different status, from stock status to produc tion status, then to waiting-be-sold status, there is not any substantial chan ge in quantity until they are sold. So we must comprehensively analyze the relat ions among each link based on integral production system, to optimize the materi al batch and cut short production cycle in order to optimize the whole system. In this paper, the production system is taken as a global entity, and in which m aterials variation law and their relations of each link are analyzed; To optimiz e the whole materials flow, a new model of multi-product systems’ economic orde r batch, economic production batch and optimal sale lot multi-product syste ms’ is developed which based on the limit of capitals and stock area.
基金supported by King Saud University,Deanship of Scientific Research,College of Science Research Center
文摘We investigate a basisity problem in the space =lpA(D)and in its invariant sub-spaces. Namely, let W denote a unilateral weighted shift operator acting in the spacelpA(D), 1≤p《∞, by W zn=λnzn+1, n≥0, with respect to the standard basis λzn+1 n≥0. Applying the so-called "discrete Duhamel product" technique, it is proven that for any integer k ≥1 the sequence {(wi+nk)-1|W |Ei)knf}n≥0 is a basic sequence in Ei :=span{zi+n :n≥0} equivalent to the basis {zi+n}n≥0 if and only if fb(i) 6= 0. We also investigate a Banach algebra structure for the subspaces Ei, i≥0.
基金supported by Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory(KX152600015/ITD-U15006)National Natural Science Foundation of China(No.61401196)
文摘Sine Non-linear Chirp Keying(SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some parameter estimation issues over conventional modulation schemes. In this paper, a novel transform termed as Discrete Sinusoidal Frequency Modulation transform(DSFMT) is proposed. Then, the DSFMT of SNCK signal is deduced and classified into three types, based on which, the time-bandwidth product is estimated by the proposed algorithm. Simulation results show that the noise has a signifi cant impact on the localization of the peak value and the time-bandwidth product can be estimated by using local ratio values when.
基金This paper was supported by the National Natural Science Foundation of China (Grant No. 71372007). We also would like to extend our sincere gratitude to the reviewers for their instructive advices and useful suggestions on this paper. Special thanks should go to the friends who have put considerable time and effort into their comments on the draft.
文摘3D printing has become a promising technique for industry production. This paper presents a research on the manufacturability optimization of discrete products un- der the influence of 3D printing technology. For this, we first model the problem using a tree structure, and then formulate it as a linear integer programming, where the total production time is to be minimized with the production cost constraint. To solve the problem, a differential evolution (DE) algorithm is developed, which automatically determines whether tra- ditionai manufacturing methods or 3D printing technology should be used for each part of the production. The algorithm is further quantitatively evaluated on a synthetic dataset, com- pared with the exhaustive search and alternating optimization solutions. Simulation results show that the proposed algo- rithm can well combine the traditional manufacturing meth- ods and 3D printing technology in production, which is help- ful to attain optimized product design and process planning concerning manufacture time. Therefore, it is beneficial to provide reference of the widely application and further in- dustrialization of the 3D printing technology.
文摘A positivity-preserving, conservative and entropic numerical scheme is presented for the three-temperature grey diffusion radiation hydrodynamics model. Moreprecisely, the dissipation matrices of the colocalized semi-Lagrangian scheme are de-fined in order to enforce the entropy production on each species (electron or ion) proportionally to its mass as prescribed in [34]. A reformulation of the model is then considered to enable the derivation of a robust convex combination based scheme. Thisyields the positivity-preserving property at each sub-iteration of the algorithm whilethe total energy conservation is reached at convergence. Numerous pure hydrodynamics and radiation hydrodynamics test cases are carried out to assess the accuracy of themethod. The question of the stability of the scheme is also addressed. It is observedthat the present numerical method is particularly robust.