Optimal management of the N-policy M/Ek/1 queuing system with a removable service station: a sensitivity investigation

2004 ◽  
Vol 31 (7) ◽  
pp. 1001-1015 ◽  
Author(s):  
W.L. Pearn ◽  
Y.C. Chang
2021 ◽  
Vol 1 (48) ◽  
pp. 83-100
Author(s):  
Hodovaniuk P ◽  
◽  
Khavruk V ◽  
Chub A ◽  
◽  
...  

The article considers the components of the target function of optimization of HUNDRED losses associated with the introduction of the post (posts) of acceptance-diagnosis with the increase of the set of diagnostic equipment. In particular, the target function of optimizing losses at the service station is presented in the form of an economic criterion that takes into account the maximum possible number of components on which depends the technological efficiency of the service station and the level of "satisfaction" of car owners with services. The object of research is a car service station. The purpose of the work is to conduct a study of the target function of optimization of HUNDRED losses associated with the type of organization of acceptance-diagnosis of cars and to find out algorithms for finding the components of the target function based on the representation of HUNDRED as a queuing system. Research method - analysis and formalization: quantitative indicators of the objective function, methods of forming a group of events, alternative solutions and calculation of the main components of optimization of HUNDRED losses as a queuing system. It is established that the target function of optimization of HUNDRED losses has economic essence and can be presented in the form of complex criterion. It is found that based on the theory of queuing for the area of reception-diagnosis it becomes possible to find solutions of the system of equations that describe its current state, namely: 1) the probability that the system has no requirements, ie free all "workers »Posts and no applications in the queue; 2) the probability of finding the system in a certain state; 3) the probability of denial of the received application for maintenance, ie the probability of finding the system in the last valid state; 4) the average number of occupied reception posts. Similar solutions were found for the TO-R zone. The formulas for determining the components of the duration of the application are considered and given. The formulas for determining the average value of the duration of work in the area of maintenance by the flow of faults and their share in the total flow of applications. The necessity of the 5th - 6th step of building the equipment in the reception-diagnostic area for detection of additional malfunctions (hidden defects) is substantiated. It is established that the average processing time of the application at the posts of acceptance-diagnosis includes three components: 1) the average time of acceptance-diagnosis of the declared ambiguous manifestation of the fault; 2) the average time of additional preliminary diagnosis on the application, which contained ambiguous manifestations of malfunctions. Depends on the number of diagnostic operations performed and the available equipment; 3) the average time of additional diagnosis on the application, which either did not contain ambiguous manifestations of malfunctions, or they did not fall within the capabilities of the existing diagnostic complex at the reception. The results of the article can be used to model the operation of the service station as a queuing system in computer software products and will reveal the low efficiency of diagnosing the main systems of cars in a particular service station. KEY WORDS: DIAGNOSTIC PARAMETER, APPLICATION, PROBABILITY, FAULT, EQUIPMENT, POST, PROFIT, ACCEPTANCE-DIAGNOSIS, SYSTEM.


Author(s):  
Sergey Vasil'ev ◽  
Vyacheslav Schedrin ◽  
Aleksandra Slabunova ◽  
Vladimir Slabunov

The aim of the research is a retrospective analysis of the history and stages of development of digital land reclamation in Russia, the definition of «Digital land reclamation» and trends in its further development. In the framework of the retrospective analysis the main stages of melioration formation are determined. To achieve the maximum effect of the «digital reclamation» requires full cooperation of practical experience and scientific potential accumulated throughout the history of the reclamation complex, and the latest achievements of science and technology, which is currently possible only through the full digitalization of reclamation activities. The introduction of «digital reclamation» will achieve greater potential and effect in the modernization of the reclamation industry in the «hightech industry», through the use of innovative developments and optimal management decisions.


2019 ◽  
Author(s):  
Nimasha Wijesinghe ◽  
Samantha Drew ◽  
Annaruby Cunjamalay ◽  
Sasha R Howard ◽  
Rakesh Amin ◽  
...  

2011 ◽  
Vol 9 (2) ◽  
pp. 87 ◽  
Author(s):  
Preeti Chandra ◽  
Saurav Chatterjee ◽  
Nishant Koradia ◽  
Deepak Thekkoott ◽  
Bilal Malik ◽  
...  

Background:Coronary perforation during percutaneous coronary intervention is a rare but dreaded complication. The risk factors, optimal management, and outcome remain obscure.Objectives:To determine the predisposing factors, optimal management, and preventive strategies. We retrospectively looked at coronary perforations at our catheterization laboratory over the last 10 years. We reviewed patient charts and reports. Two independent operators, in a blinded approach, reviewed all procedural cineangiograms. Data were analyzed by simple statistical methodology.Results:Nine patients were treated conservatively and six patients were treated with prolonged balloon inflation. Six patients were treated with polytetrafluoroethylene (PTFE)-covered stents. One patient required emergency coronary artery bypass graft. No deaths were reported. Subjects with perforations also had a significantly higher total white blood cell count (means 12,134 versus 6,155, 95 % confidence interval [CI], p< 0.0001, n=22), total absolute neutrophil count (means 74.2 % versus 57.1 %, 95 % CI, p<0.0001, n=22), and neutrophil:lymphocyte ratio (means 3.65 versus 1.50, 95% CI, p<0.0001, n=22).Conclusions:Coronary perforations are rare but potentially fatal events. Hypertension, small vessel diameter, high balloon:artery ratio, use of hydrophilic wires, and presence of myocardial bridging appear to be possible risk factors. Most perforations can be treated conservatively or with prolonged balloon inflation using perfusion balloons. Use of PTFE-covered stents could be a life-saving measure in cases of large perforations. Subjects with perforations also had greater systemic inflammation as indicated by elevated white cell counts.


2012 ◽  
Vol 44 (12) ◽  
pp. 43-54 ◽  
Author(s):  
Agasi Zarbali ogly Melikov ◽  
Leonid A. Ponomarenko ◽  
Che Soong Kim

Sign in / Sign up

Export Citation Format

Share Document