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1.
The paper is a succession of [1, 2]. Using MSP, we give a new approach to calculate the transient distribution of the length and waiting time of GI/G/1 queueing system.  相似文献   

2.
This paper introduces a new concept of 4PL, which is a contractor of the closed-loop supply chain coordination based on the division of community and the outsourcing development. The concept enriches the connotation of 4PL and broadens the thought for 4PL development. Secondly, according to the characteristics of the closed-loop supply chain in the different duration of the collaborative relationship and the dynamic characteristics of the closed-loop supply chaini we apply the fractal theory to establish a fractal system of 4PL coordinating closed-loop supply chain and propose different strategies for 4PL coordinating with different types of closed-loop supply chains in the various links of the system. Moreover, some strategic and proactive thinking are provided for 4PL's practices. Then based on the exergoeconomics theory, the closed-loop supply chain is regarded as a huge energy system with the new view, and the sustainability of the closed-loop supply chain system is discussed under the circumstance of exergoeconomics, and then the metric about “system negative environment effect” is introduced to measure the closed-loop supply chain system performance in the point of energy, a case study illustrates our conclusions.  相似文献   

3.
MAKING AND VALIDATING COMPLEX DECISIONS WITH THE AHP/ANP   总被引:11,自引:1,他引:11  
1.Introduction Rational decision-making is the talent we have to be more effective in implementing our ideas in the real world with its risks and resistance to change.Decision-making involves prioritizing our ideas according to the circumstances we face now or might face in the future.A fundamental problem in decision-making is how to measure intangible criteria and how to interpret correctly measurements of tangibles so they can be combined with those of intangibles to yield sensible,not arbi…  相似文献   

4.
This paper describes the characteristics of a single-base repairable inventory system and multi-indenture structure with communality and redundancy. At the base, there are a working field that has a maximum of z equipment on line and its repair channels, which mainly consist of two centers: line replaceable units (LRUs) diagnostic center and shop replaceable units (SRUs) repair center. In these two centers, the resources are finite and different. We introduce routing probabilities to express the repair relationships between resources and failed replaced units. The diagnostic time follows exponential distribution and SRU repair time follows general distribution with known average. We analyze the general model of this system, and present an approximate solution that uses two-step negative binomial approximation to obtain the expected backorders of all LRUs. The first step is fitting negative binomial distributions to the distributions of the number for all SitUs at the repair center, and the second is fitting negative binomial distributions to the convolutions of the distributions of the number for all LRUs in diagnostic and assemblydelayed. Thus, we give the approximate value of operational awilability of equipment based on this method. Finally, the results under two policies of routing probabilities are compared by the optimal curves.  相似文献   

5.
Scheduling with Rejection and Non-Identical Job Arrivals   总被引:5,自引:1,他引:4  
In this paper, we address the scheduling problem with rejection and non-identical job arrivals, in which we may choose not to process certain jobs and each rejected job incurs a penalty, Our goal is to minimize the sum of the total penalties of the rejected jobs and the maximum completion time of the processed ones, For the off-line variant, we prove its NP-hardness and present a PTAS, and for the on-line special case with two job arrivals, we design a best possible algorithm with competitive ratio (√5+1/2) .  相似文献   

6.
Like value chain and supply chain, “industrial chain” becomes the focus of attention. The implication of “industrial chain” has gained a large range of extension. It not only expresses the industrial “chain” structure and relationship of “back and forward”in order or “up and down” in direction, but also it represents a cluster of large scale of firms in an area or colony. It is a network, or a community. Consequently, we conclude that “industrial chain” is a synthesis of industrial chain, industrial cluster, or industrial network.In this article, firstly we will distinguish industry chain from industry. An industry is the collection of firms that have the same attribute, so an industry can be defined by firm collection of certain attribute. We indicate that industrial chain is a kind of vertical and orderly industrial link. It is defined according to a series of specific product or service created. Secondly we analyze the vertical orderly defiinition process from the aspects of social division of labor and requirement division, self-organization system, and value analysis.Non-symmetry and depending on system or community of large scale of industrial units lead to entire industry to “orderly” structure. On the other hand, the draught of diversity and complexity of requirement simultaneously lead to entire industry to be more “orderly”. Along with processes of self-organization, industrial will appi‘oach the state of more orderly and steady, and constantly make industrial chain upgrade. Each firm or unit, who will gain the value, has to establish channels of value, which we called “industrial value chain”. Lastly,we discuss the consequence of vertical and orderly definition, which is exhibited by a certain relationship body. The typical forms of industrial chain include industrial cluster, strategy alliance and vertical integration etc.  相似文献   

7.
In the existing literature of Repairable Queueing Systems (RQS), i.e., queueing systems with server breakdowns, it is almost all assumed that interarrival times of successive customers are independent, identically exponentially distributed. In this paper, we deal with more generic system GI/PH/1 with server‘s exponential uptime and phase-type repair time. With matrix analysis theory, we establish the equilibrium condition and the characteristics of the system, derive the transient and stationary availability behavior of the system.  相似文献   

8.
This paper deals with the solution of a neutron transport equation with parameter δ.Usingthe theory of functional analysis,we discuss the distribution of the parameters which make the equationhave a non-zero solution,and obtain a necessary and sufficient condition for the existence of thecontrol critical eigenvalue δ_0 which possesses a physical meaning.  相似文献   

9.
In this paper, we derive a lattice model for a single species on infinite patches of one-dimensional space with that the maturation could occur at any age. The formulation involves a distribution of possible ages of maturation and a probability density function on which ecological assumptions are made. The following results are obtained: the existence and isotropy of the unique nonnegative solution for initial value problem, the extinction of the species provided with the non-existence of positive equilibria, and the existence of wavefronts with the wave speed c 〉 c*.  相似文献   

10.
Using outward rotations, we obtain an approximation algorithm for MAX n/2-UNCUT problem, i.e., partitioning the vertices of a weighted graph into two blocks of equal cardinality such that the total weight of edges that do not cross the cut is maximized. In many interesting causes, the algorithm performs better than the algorithms of Ye and of Halperin and Zwick. The main tool used to obtain this result is semidefinite programming.  相似文献   

11.
考虑一类有正、负顾客, 带启动期和有备用服务员的M/M/1休假排队系统. 负顾客一对一抵消队尾的正顾客(若有), 若系统中无正顾客, 到达的负顾客自动消失, 负顾客不接受服务.系统中两个服务员, 其中一个在岗工作时另外一个备用.上岗服务员若因为某种原因休假, 备用服务员立即替换上岗.当系统变空时, 系统关闭.用拟生灭过程和矩阵几何解方法, 得到了稳态队长的分布, 此外, 证明了稳态条件下队长的条件随机分解并得到了附加队长的分布. 最后, 通过两个数值例子说明该模型可以较好的模拟一些实际问题.  相似文献   

12.
本文把“修理设备可发生故障”引入到N-策略M/G/1可修排队系统中,考虑了 修理设备可更换的N-策略M/G/1可修排队系统.通过引进服务台的“广义修理时间”、顾客的“广义服务时间”和修理设备的“广义忙期”,讨论了系统的排队指标和服务台的可靠性指标.同时,使用全概率分解方法,利用拉普拉斯变换工具,重点讨论了修理设备的不可用 度和在(0,t]时间内的平均更换次数,并给出了数值计算实例.最后,本文在给定的费用结构下 讨论了最优策略N*的求解问题,并给出了数值计算例子.  相似文献   

13.
综合运用补充变量方法和基于条件概率矩阵迭代的嵌入Markov链方法研究了具有负顾客到达和RCH移除策略的离散时间GI/D-MSP/1/N排队系统. 获得了稳态情形下正顾客到达前夕, 任意时隙分点以及外部观测时刻的三种队长分布. 并进一步讨论了可入系统正顾客的等待时间分布. 最后通过几个特殊情形下的数值算例验证了计算方法理论分析的正确性.  相似文献   

14.
综合利用离散补充变量法、矩阵几何解及拟生灭链的方法研究了带有负顾客及伯 努利反馈的Geo/Geo/1多重工作休假排队系统. 首先运用离散补充变量方法得 到了此复杂系统的转移概率矩阵. 其次, 再利用矩阵几何解及拟生灭链的技术通 过解方程组获得了队长的稳态分布、平均队长及稳态队长的随机分解结果. 最后, 通过引入数值例子, 作出了系统的二维图形, 进而可以更直观地分析一些参数 对系统性能的影响.  相似文献   

15.
本文考虑了具有温储备失效特征的M/G/1可修排队系统.在该系统中,服务台故障分为两类:第一类是服务台在服务员的"广义忙期"中以故障率为α(0≤α∞)的泊松过程发生故障,第二类是服务台在系统闲期中以分布函数为Y(t)的更新过程发生故障,而且发生第二类故障时不能得到立即修理.利用全概率分解技术和拉普拉斯变换工具,分别讨论了在两类故障模式下服务台的瞬态不可用度和稳态不可用度,(0,t]时间内的平均故障次数和稳态故障频度等可靠性指标,进一步还讨论了服务台由温储备失效引起等待修理的概率.最后,通过数值计算例子讨论了系统有关参数对服务台的第二类稳态不可用度和第二类稳态故障频度的影响.  相似文献   

16.
本文把“服务台在系统闲期中可能温储备失效”引入到M/G/1可修排队系统中,考虑了具有温储备失效特征的M/G/1可修排队系统.使用全概率分解技术和利用拉普拉斯变换工具,导出了在任意时刻t队长的瞬态分布的拉普拉斯变换的表达式,进一步获得了队长的稳态分布的递推式,同时,给出了稳态队长和稳态等待时间的随机分解结果. 最后通过数值计算实例讨论了平均附加队长随温储备失效参数和修复参数的变化情况.  相似文献   

17.
SELF-ADAPTIVE CONTROLS OF A COMPLEXCELLULAR SIGNALING TRANSDUCTION SYSTEM   总被引:3,自引:0,他引:3  
In cells, the interactions of distinct signaling transduction pathways originating from cross-talkings between signaling molecules give rise to the formation of signaling transduction networks, which contributes to the changes (emergency) of kinetic behaviors of signaling system compared with single molecule or pathway. Depending on the known experimental data, we have constructed a model for complex cellular signaling transduction system, which is derived from signaling transduction of epidermal growth factor receptor in neuron. By the computational simulating methods, the self-adaptive controls of this system have been investigated. We find that this model exhibits a relatively stable selfadaptive system, especially to over-stimulation of agonist, and the amplitude and duration of signaling intermediates in it could be controlled by multiple self-adaptive effects, such as "signal scattering", "positive feedback.", "negative feedback" and "B-Raf shunt". Our results provide an approach to understanding  相似文献   

18.
This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By using space sparse sampling, great memorial capacity can be saved and reproduced scenes can be controlled. To solve time consuming and complex computations in three-dimensional interpolation algorithm, we have studied a fast and practical algorithm of scattered space lattice and that of "Warp" algorithm with proper depth. By several simple aspects of three dimensional space interpolation, we succeed in developing some simple and practical algorithms. Some results of simulated experiments with computers have shown that the new method is absolutely feasible.  相似文献   

19.
可信软件中非功能需求FO-QSIG冲突权衡模型   总被引:1,自引:0,他引:1  
引入领域工程中FODA模型中"特征"概念到需求工程中QSIG图中,提出了面向特征定量软目标耦合图(FO-QSIG);用FO-QSIG图对可信软件系统的非功能需求(NFR)的冲突和不确定性进行完整性表述;并建立FO-QSIG权衡模型对NFR之间的优先排序和正负影响进行定量分析,通过计算NFR的特征贡献值(FC),来消解NFR之间冲突和不确定性;最后对FO-QSIG模型的可信性进行了证明。为可信软件中NFR精化提供了新的权衡分析工具。  相似文献   

20.
无线射频(radio frequency identification,RFID)技术能够消除需求信息不对称并减小需求预测误差,同时增加供应链的运作成本,如何分析RFID标签成本的影响并协调链上成员的收益是本文研究的问题.本文通过建立RFID采用前后分散式和集中式供应链的收益模型,分析了RFID标签成本阈值对批发价、服务水平和协调参数的影响;在此基础上通过两部定价契约进行协调.研究发现:分散式供应链"双重边际化"效应的大小与RFID标签成本负相关;当RFID标签成本位于某一阈值时,采用RFID能够提升分散式供应链的服务水平并实现成员收益的Pareto改进,同时降低制造商的批发价;集中式供应链采用RFID会降低服务水平;两部定价契约均能协调RFID采用前后的供应链,但是采用RFID后契约的批发价参数变大,固定费用参数区间的上下界及范围均与RFID标签成本负相关.  相似文献   

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