New recursive estimators of the time-average variance constant

2015 ◽  
Vol 26 (3) ◽  
pp. 609-627 ◽  
Author(s):  
Chun Yip Yau ◽  
Kin Wai Chan
2010 ◽  
Vol 24 (2) ◽  
pp. 201-218
Author(s):  
James M. Calvin

We consider the steady-state simulation output analysis problem for a process that satisfies a functional central limit theorem. We construct an estimator for the time-average variance constant that is based on excursions of a process above the minimum. The resulting estimator does not require a fixed run length, and the memory requirement can be dynamically bounded. Standardized time series methods based on excursions are also described.


2000 ◽  
Vol 14 (2) ◽  
pp. 179-201 ◽  
Author(s):  
James M. Calvin ◽  
Marvin K. Nakayama

The classical regenerative method of simulation output analysis exploits the regenerative structure of a stochastic process to break up a path into independent and identically distributed cycles based on a single sequence of regeneration times. If a process is regenerative with respect to more than one sequence of regeneration times, the classical regenerative method does not exploit the additional structure, and the variance of the resulting estimator for certain performance measures (e.g., the time-average variance constant) can vary greatly, depending on the particular regeneration sequence chosen. In a previous article, we introduced an efficiency-improvement technique for regenerative simulation of processes having two sequences of regeneration times based on permuting regenerative cycles associated with the second sequence of regeneration points. In this article, we show how to exploit more than two regeneration sequences. In particular, for birth–death Markov chains, the regenerations associated with hitting times to each state can all be exploited. We present empirical results that show significant variance reductions in some cases, and the results seem to indicate that the permuted estimator for the time-average variance constant can have a variance that is independent of the primary regeneration sequence used to run the simulation.


2019 ◽  
Vol 118 (11) ◽  
pp. 552-562
Author(s):  
Nguyen Thi Ngan ◽  
Bui Huy Khoi

This research aims to assess the service quality of industrial parks (IP) in the view of FDI (foreign direct investment) firms in Vietnam. Data was collected from 270 FDI firms in Vietnam - Singapore Industrial Parks (VSIP) in Vietnam. The proposed research model was based on researches on service quality. Cronbach's Alpha Average Variance Extracted (Pvc),rho (ρA), and Composite Reliability (Pc) tested the reliability and validity of the scale. The analysis results showed that four factors were affecting the servicequality of industrial park in Vietnam being tangibleof VSIP, reliability of VSIP, the empathyof FDI investors, and their assurance. The responsivenessof VSIP did not affect the servicequality of the industrial park. Contents of the article focus on two main issues: the analysis framework of the quantitative model and implicating results todevelop the industrial park services. The limitation of the research was only in VSIP in Vietnam.


2019 ◽  
Vol 118 (10) ◽  
pp. 216-223
Author(s):  
Nguyen Thi Ngan ◽  
Bui Huy Khoi

The purpose of the paper was to investigate the factors that influenced the intention to use coffee by using Adanco software. Survey data was collected from 284 consumers living in Ho Chi Minh City, Vietnam. The research model was proposed from the studies of the behavioral intention. The reliability and validity of the scale were tested by Cronbach's Alpha, Average Variance Extracted (Pvc) and Composite Reliability (Pc). PLS-SEM showed that intention to use coffee was affected by some components of the intention to use coffee.


Author(s):  
R. Irawan

Leap frog concept was created to address the loss of single joint rig agility and drive the cycle time average lower than ever. The idea is to move the preparation step into a background activity that includes moving the equipment, killing the well, dismantling the wellhead and installing the well control equipment/BOP before the rig came in. To realize the idea, a second set of equipment is provided along with the manpower. By moving the preparation step, the goal is to eliminate a 50% portion of the job from the critical path. The practice is currently performed in tubing pump wells on land operations. However, the work concept could be implemented for other type of wells, especially ESP wells. After implementation, the cycle time average went down from 18 hours to 11 hours per job, or down by ~40%. The toolpusher also reports more focused operations due to reduced scope and less crew to work with, making the leap frog operation safer and more reliable. Splitting the routine services into 2 parts not only shortened the process but it also reduces noise that usually appear in the preparation process. The team are rarely seen waiting on moving support problems that were usually seen in the conventional process. Having the new process implemented, the team had successfully not only lowered cycle time, but also eliminated several problems in one step. Other benefits from leap frog implementation is adding rig count virtually to the actual physical rig available on location, and also adding rig capacity and completing more jobs compared to the conventional rig. In other parts, leap frog faced some limitation and challenges, such as: limited equipment capability for leap frog remote team to work on stuck plunger, thus hindering its leap frog capability, and working in un-restricted/un-clustered area which disturb the moving process and operation safety.


Author(s):  
Rajesh Kumar Verma ◽  
Chhabi Rani Panigrahi ◽  
Bibudhendu Pati ◽  
Joy Lal Sarkar

Background & Objective: Multimedia aggregates various types of media such as audio, video, images, animations, etc., to form a rich media content which produces an everlasting effect in the minds of the people. Methods: In order to process multimedia applications using mobile devices, we encounter a big challenge as these devices have limited resources and power. To address these limitations, in this work, we have proposed an efficient approach named as mMedia, wherein multimedia applications will utilize the multi cloud environment using Mobile Cloud Computing (MCC), for faster processing. The proposed approach selects the best available network. The authors have also considered using the Lyapunov optimization technique for efficient transmission between the mobile device and the cloud. Results: The simulation results indicate that mMedia can be useful for various multimedia applications by considering the energy delay tradeoff decision. Conclusion: The results have been compared alongside the base algorithm SALSA on the basis of different parameters like time average queue backlog, delay and time average utility and indicate that the mMedia outperforms in all the aspects.


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