Machine Interference Research Articles

On the multi-server machine interference with modified Bernoulli vacation

We study the multi-server machine interference problem with repairpressure coefficient and a modified Bernoulli vacation. The repairrate depends on the number of failed machines waiting in the system.In congestion, the server may increase the repair rate with pressurecoefficient $\theta$ to reduce the queue length. At each repair completion ofa server, the server may go for a vacation of random length withprobability $p$ or may continue to repair the next failed machine, ifany, with probability $1-p$. The entire system is modeled as afinite-state Markov chain and its steady state distribution isobtained by a recursive matrix approach. The major performancemeasures are evaluated based on this distribution. Under a coststructure, we propose to use the Quasi-Newton method andprobabilistic global search Lausanne method to search for the globaloptimal system parameters. Numerical examples are presented todemonstrate the application of our approach.

Applying the machine repair model to improve efficiency of harvesting fruit

Harvest costs are generally the single greatest expense for specialty crop producers. Identifying and reducing inefficiencies during harvest are essential steps towards reducing costs and maintaining product quality. To streamline harvest operations, the number of workers and machines required to harvest, handle, and transport the product needs to be planned along with the execution of field operations. In this paper the fruit harvest and the bin collection process are modelled, adopting a modified machine repair model (machine interference problem) from the operations research area. An algorithm was developed in Matlab® to evaluate the performance of the system and improve confidence in sizing the fleet (workers and machines). Two different case studies are modelled using this algorithm: i) manual table grape harvest in Greece, and ii) manual sweet cherry harvest in Washington State, USA. First, the harvest procedures are described, and then the machine repair model is formulated to model each process. The bin loading process during grape harvest in Greece, and the sweet cherry picking process in USA are simulated. System performance under different number of bin carriers (or pickers) and loading stations is evaluated and results are presented.

A multinomial model for the machine interference problem with different service types and multiple operators

This paper proposes a model for a special case of the machine interference problem (MIP), where each of N identical machines randomly requests several different service types. Each request for a service type is fulfilled by an operator who can provide only one service type. The model allows the calculation of the expected interference (waiting) time in the queue for each service type, according to the multinomial distribution. The uniqueness of the model is that under its assumptions internal service order and queue discipline are not needed for the interference calculations. The model requires as inputs only the machine runtime and the average time of each service type that is needed to produce one unit. These inputs can be obtained by a common work measurement. The model enables practitioners to determine the optimal numbers of operators that are needed for each service type in order to minimize the cost per unit or maximize the profit, or to set other performance measures. To demonstrate the applicability of the model, a theoretical analysis and a case study are presented.

Determining the operator-machine assignment for machine interference problem and an empirical study in semiconductor test facility

Semiconductor is a capital-intensive industry in which equipment costs account for more than seventy percentage of the capital investment in semiconductor test facilities. In an industrial investigation, the machine interference may be 10% of machine time. Hence, there is a need to assign an appropriate number of machines to the operators to minimize machine interference time or labor cost. This paper aims to develop an effective methodology to determine the optimal assignment relationships between the test machines and the operators for different product mixes to enhance utilization for the optimal system performance. In particular, we employed response surface methodology and genetic algorithms to explore alternative assignment rations and thus identify well-performed assignment alternatives for the test machines and operators in various decision contexts with simulation. An empirical study with real data collected was conducted in a semiconductor test facility to validate this approach. The results have shown the validity of the proposed approach in real settings. Indeed, the developed approach has been implemented on line.

Economic Impact of Truck–Machine Interference in Forest Biomass Recovery Operations on Steep Terrain

Abstract In forest biomass recovery operations from harvest residues, processing equipment can work most productively if they can work without interference or waiting on trucks. A deterministic simulation model was developed to estimate the economic effect of truck–grinder interference in forest biomass processing and transport operations on steep terrain. Truck–machine interference can occur in situations where the grinder is waiting for trucks or vice versa. We analyzed how the number of available trucks and road characteristics affect grinder utilization and biomass delivery cost. Three cases based on different road characteristics were designed and applied to actual operations in order to illustrate how particular road features in relation to the spatial location of the grinder can affect the economics of the operation. An economic model was also developed to estimate the waiting cost of trucks and machinery due to truck–machine interferences. Grinder location in relation to available truck turnaround, turnouts, truck turning-around time, truck positioning time, and distance traveled on each road surface have a significant effect in forest residues processing and transport economics at the operational level. After the optimization was performed, the grinder utilization rate on a harvest unit with highly constrained road access reached 60 percent using six trucks. Waiting cost represented 15.15 percent of total grinding cost. On the medium constrained road access harvest unit, maximum grinder utilization reached 77 percent using five trucks. A loop road case resulted in a grinder utilization rate of 81 percent using five trucks.

Use of Statistical Quality Control for Estimating the Machine Interference

Although it is important to test quality of coal used in thermal power station, it is more important to know how to interpret the data from the results. No single test can be used independently to determine the quality of coal. Machine interference is a significant problem in many manufacturing system and testing equipments. The variation of results for testing equipments may be due to various factors which need to calculate the uncertainty of measurement to show the accuracy of the machine. In case of coal testing laboratory, the plant layout and surrounding environment affects the performance of the system. The machine interference comes under variable cause which may effect on the result. This paper, proposes a methodology for constructing system performance measures, finding out the various factors responsible for variations in result. The study is based on performance of coal used in thermal power station in India. The paper deals with estimation of machine interference existence using variable control chart approach for coal testing equipments. The paper gives the solution for the coal testing laboratory to improve their performance. The analysis of results for such machine interference will be useful and significant for system designers and practitioners.

Steady –State Solution of the Queue E_r/M/2/k/N With Heterogeneous Repairmen

The machine interference queue with Erlangian interarrival and exponential service time is solved for the steady-state case and heterogeneous repairmen .The queue discipline considered here is first in first out(FIFO)with a more general condition . The recurrence relations that give all the probabilities in terms of and some measures of effectiveness are derived. Also, some special cases are deduced.

Comparative analysis for periodical and random servicing systems considering different working circumstances: A textile application

As is in the textile industry, in some industries the selection of the operator servicing system to improve machines’ efficiencies is made intuitively or according to historical experiences generally. However, these preferences are not felicitous in any case. On the other hand, to estimate and analyze the machine efficiency in the case of multimachine assignment is a difficult issue due to machine interference problem. The solutions proposed such as the prepared tables, analytical formulas and queuing theory are generally for a limited number of machines and involve complex and tedious calculations and are generally insufficient for detailed analysis. In this paper, considering some working circumstances, the effect of random and periodical operator servicing systems on the machine efficiency is compared by using simulation methodology. Also, the algorithm of one of the simulation programs used is given. This study indicates that if the average stoppage rates of the machines assigned to the operator is small and the numbers of these machines are large then the random operator servicing system has superiority over the periodical operator servicing system.

Using economic X control chart design methodology to estimate and optimize machine efficiency in the case of multimachine assignments

AbstractEstimation and optimization of machine efficiency in the case of multi machine assignments is a difficult issue for some industries such as textile industry, due to the machine interference. Although the problem is not new, the solutions proposed are not full satisfactory. For example, the analytical formulas are not suitable for high number of machines; queuing theory approaches are complex and impractical for mill managers. On the other hand, simulation methodology seems to be a perfect tool to estimate and analyze; however, the simulation package programs are expensive and are not suitable for systematic optimization. In this paper, Duncan's economic control chart design methodology is proposed as an alternative way for one of the oldest industrial problems. This study shows that this new approach is a more efficient solution to this stochastic problem. Copyright © 2009 John Wiley & Sons, Ltd.

A Computational Approach to the Cost Analysis of Machine Interference Model

SYNOPTIC ABSTRACTMachine interference model is one of the most important models of queueing systems and it has likely become one of the most used queueing models today. This paper deals with cost analysis of the machine interference model with balking, reneging, and spares in which a total cost function is constructed using hypergeometric functions and other parameters of the model. For simultaneous control of arrival and service parameters of the model in an optimal manner, a fast converging Newton-Raphson (N-R) method is employed and total optimal cost of the model, an important performance indicator, is computed by developing and solving a system of non-linear equations involving arrival rate, service rate, and hypergeometric functions. Various cases of the model are considered and outcomes of numerical analysis are presented graphically.

Analysis of cyclic queueing networks with parallelism and vacation

The aim of this paper is to improve the machine interference model with vacation to deal with more recent problems of the communication area. To this scope the model is extended to include parallelism in the vacation station. The underlying Markov process is analyzed and a state arrangement is found that yields an efficient matrix-analytic technique that substantially lowers down the time- and space-complexity of standard methods. A numerical example of the method effectiveness is presented, and an example of resource allocation is introduced that finds applications in the QoS management of wireless networks.

An Optimal Queuing Model by Dynamic Numbers of Repairman in Finite Population Queuing System

This paper solves the machine interference problem in which N machines grouped by r groups and each group are looked after by an operative. It is assumed the machines of each group are identical and the run times of the machines in i th group have a general distribution, and the repair times i th group are assumed to have a negative exponential distribution with mean 1/ μi and furthermore we suppose the (i − 1) th group has priority over i th group and whenever an operative becomes free, then he will pay to next group. An explicit expression for the probability that a particular of each is found running in the steady state is derived. For this other useful results for the system can be obtained by using the steady-state probability distribution. It is shown that, these depend on the run time distribution only through the means of this distribution.

Computational approach to the cost analysis of dual machine interference model with general arrival distribution

AbstractIn this paper, a fresh attempt has been made to apply a computational approach to obtain the optimal total cost of the system as an important performance measure for the machine interference model with general arrival distribution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A Lagrangian dynamic analysis of end effects in a generalized shear experiment

In laboratory shear testing, a primary source of error is the surcharge force caused by relative motion between the displacement actuator and dilating top sample. This force is referred to as end friction, and the changes it produces in experimental data are termed end effects. The results from a laboratory shear setup always represent a superposition of natural sliding behavior and testing machine interference; their relative proportions can be determined by externally modeling the experiment. In this paper, we construct a full Lagrangian dynamic model for the shearing behavior of a prismatic aluminum top-block over a matching asymmetric foundation. End friction is initially included in the analysis, whose viability is established by comparing modeled and experimental top-block sliding paths at 12 different shear loads. The end friction force is ultimately removed from the formulation, and the end effects manifested as the subsequent differences between modeled and experimental sliding paths. It is shown that end effects significantly alter both the sliding path and rotation mode of the prismatic top-sample. While their impact on the trajectory of a given sample appears to decrease with increasing shear force, it is shown that uniform sample scaling does nothing to alleviate the problem, and that end effects are functionally scale independent.

A survey of the machine interference problem

This paper surveys the research published on the machine interference problem, also called the machine repairman problem, in which machines interfere with each other’s service. Our emphasis is on work that has appeared since the 1985 review by Stecke and Aronson. After describing the basic model and the scope of our study, we discuss the literature along several dimensions. We describe some of the more interesting papers, and offer some suggestions for topics holding particular promise for future studies. We conclude with comments about how the research has evolved over the past two decades.

VACATION POLICIES FOR MACHINE INTERFERENCE PROBLEM WITH AN UN-RELIABLE SERVER AND STATE-DEPENDENT SERVICE RATE

ABSTRACT This paper studies the machine interference problem consisting of M operating machines and an un-reliable server who leaves for a vacation of random length when there are no failed machines queuing up for repair in the repair facility. At the end of the vacation the server returns and operates two different vacation policies. In Policy 1, the server doesn't take a vacation again and remain idle until the first arriving failed machine arrives, which starts a busy period in the repair facility. In Policy 2, the server takes vacations repeatedly until they find the repair facility has at least one waiting failed machine in the queue. For both policies, a profit model is developed in order to determine the optimal value of the number of machines. Numerical results are provided in which several system characteristics are evaluated under optimal operating conditions.

Queueing network model for a single-operator machine interference problem with external operations

Machine interference is a significant problem in many manufacturing systems. Prior research shows that machine interference may be as high as 10% of machine time. This paper proposes a queueing network model for a single-operator, machine interference problem with external operations, i.e., those tasks that can be completed while the machine is running. The interactions for part/machine and machine/operator are modeled as an open and a closed queueing network, respectively. In the open network, part inter-arrival time follows an exponential distribution. In both networks, service times follow a general distribution that is characterized by their first two moments. An iterative procedure is developed to solve the proposed model. Solution quality is justified by an industry-based case study. Data were collected from the integrated circuit (IC) ink-marking machines of a leading IC packaging company in Taiwan that allowed the construction of an experimental design for computational tests that encompassed a wide range of production scenarios. Empirical results show promise for the proposed methodology in helping to solve industrial problems. Model limitations as well as future research opportunities are discussed.

A mathematical programming approach to the machine interference problem with fuzzy parameters

Machine interference is an important problem frequently encountered in production and manufacturing operations such as semiconductor manufacturing and maintenance operations. Due to uncontrollable factors, parameters in the machine interference problem may be fuzzy. This paper proposes a mathematical programming approach to construct the membership function of the performance measure of the machine interference system with the machine breakdown rate and the service rate being fuzzy numbers. On the basis of the extension principle, a pair of mathematical programs is formulated to calculate the lower and upper bounds of the fuzzy performance measure at possibility level α. By enumerating different values of α, the membership function of the system performance measure is constructed. A numerical example is solved successfully to demonstrate the validity of the proposed approach. Since the performance measure is completely described by a membership function rather than by a crisp value, the fuzziness of input parameters is conserved completely. Thus more information is provided for designing manufacturing systems. The successful extension of machine interference models to fuzzy environments permits machine interference models to have wider practical applications.

The service Erlangian machine interference model:M/E r /1k/N with balking and reneging

The aim of this paper is to derive the analytical solution of the quene:M/Er/1/k/N for machine interference system with balking and reneging considering the discipline FIFO. Some measures of effectiveness and some special cases are obtained.

The cost analysis of machine interference model with balking, reneging and spares

In this paper, an attempt has been made to discuss the cost analysis of the machine interference model M/M/C/K/N. Here, we have constructed a cost function in order to determine the optimum cost of the system. In this analysis, a fast converging N - R method has been used to solve the non-linear function involving service rate and hyper geometric functions including other parameters. A computer program of above method has enabled us to crack down the root value of this exhaustive non-linear function to yield an optimal solution. In this way, an efficient evaluation of performance measure in the form of cost analysis has been possible to be carried out and consequently an important dimension of this investigation has been attempted successfully.