scholarly journals On the performance of the M1,M2/G1,G2/1 retrial queue with pre-emptive resume policy

2015 ◽  
Vol 25 (1) ◽  
pp. 153-164 ◽  
Author(s):  
Leila Boutarfa ◽  
Natalia Djellab

Priority mechanism is an invaluable scheduling method that allows customers to receive different quality of service. Service priority is clearly today a main feature of the operation of any manufacturing system. We are interested by an M1,M2/G1,G2/1 priority retrial queue with pre-emptive resume policy. For model in question, we discuss the problem of ergodicity and, by using the method of supplementary variables, find the partial generating functions of the steady state system state distribution. Moreover, some pertinent performance measures are obtained and numerical study is also performed.

2012 ◽  
Vol 22 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Nadjet Stihi ◽  
Natalia Djellab

For M/G/1 retrial queues with impatient customers, we review the results, concerning the steady state distribution of the system state, presented in the literature. Since the existing formulas are cumbersome (so their utilization in practice becomes delicate) or the obtaining of these formulas is impossible, we apply the information theoretic techniques for estimating the above mentioned distribution. More concretely, we use the principle of maximum entropy which provides an adequate methodology for computing a unique estimate for an unknown probability distribution based on information expressed in terms of some given mean value constraints.


2016 ◽  
Vol 1 ◽  
pp. 189-196
Author(s):  
Vian Harsution

Lesson study is a systematic, collaborative, and sustainable method of improving the quality of learning. Lesson study emphasizes the exploration of students’ learning needs; teacher openness towards learning difficulties encountered; the willingness of teachers to receive and provide advice and solutions to the difficulties encountered; and the consistency of the various parties to follow up the suggestions and solutions. Implementation of lesson study involving teachers, principals, and experts in the field of education. Kurikulum tingkat satuan pendidikan or abbreviated KTSP is operational curriculum formulated and implemented by each educational unit. KTSP has the characteristics, namely: giving broad autonomy to the educational unit, involving the community and parent participation, involving the democratic leadership of the principal, and require the support of a working team that is synergistic and transparent. KTSP based on the learning process, needs to be supported by a conducive learning environment and fun to be created by teachers.Teachers and principals in a professional, systematic and collaborative create an atmosphere that fosters independence, tenacity, entrepreneurial spirit, adaptive and proactive nature of the learning process. Thus, the learning needs of students who fulfilled optimally and professional ability of teacher who have increased on an ongoing basis, may usher in success – based learning KTSP. It means that the lesson study provides positive implications for the KTSP – based learning.


1999 ◽  
Vol 40 (4-5) ◽  
pp. 369-374 ◽  
Author(s):  
R. S. Fujioka ◽  
A. J. Bonilla ◽  
G. K. Rijal

An auxiliary Wetland Reclamation Facility (WRF) was constructed to receive stabilization pond treated sewage and further treat it with water hyacinth ponds, chemical flocculation, filtration and ultraviolet light disinfection. This was the first facility in Hawaii which was approved to produce the highest quality reclaimed water using alternative treatment schemes. We assessed the effectiveness of the WRF by monitoring water samples after each of the WRF treatment schemes for five genetically different groups of sewage borne microorganisms (fecal coliform, enterococci, C. perfringens, FRNA phage, total heterotrophic bacteria). The concentrations of all fecal indicator microoganisms, especially FRNA phase were low in the influent water to the WRF indicating that extended pond treatment may be especially effective in removing human viruses from sewage. The WRF treatment scheme was calculated to be able to reduce >99.99% of fecal coliform and therefore was able to produce an effluent meeting the non-potable, unrestricted reuse standard of a geometric means of <1 fecal coliform/100 ml.


2002 ◽  
Vol 20 (8) ◽  
pp. 1996-2004 ◽  
Author(s):  
P. Ross ◽  
M. Nicolson ◽  
D. Cunningham ◽  
J. Valle ◽  
M. Seymour ◽  
...  

PURPOSE: We report the results of a prospectively randomized study that compared the combination of epirubicin, cisplatin, and protracted venous-infusion fluorouracil (PVI 5-FU) (ECF) with the combination of mitomycin, cisplatin, and PVI 5-FU (MCF) in previously untreated patients with advanced esophagogastric cancer. PATIENTS AND METHODS: Five hundred eighty patients with adenocarcinoma, squamous carcinoma, or undifferentiated carcinoma were randomized to receive either ECF (epirubicin 50 mg/m2 every 3 weeks, cisplatin 60 mg/m2 every 3 weeks and PVI 5-FU 200 mg/m2/d) or MCF (mitomycin 7 mg/m2 every 6 weeks, cisplatin 60 mg/m2 every 3 weeks, and PVI 5-FU 300 mg/m2/d) and analyzed for survival, response, toxicity, and quality of life (QOL). RESULTS: The overall response rate was 42.4% (95% confidence interval [CI], 37% to 48%) with ECF and 44.1% (95% CI, 38% to 50%) with MCF (P = .692). Toxicity was tolerable, and there were only two toxic deaths. ECF resulted in more grade 3/4 neutropenia and grade 2 alopecia, but MCF caused more thrombocytopenia and plantar-palmar erythema. Median survival was 9.4 months with ECF and 8.7 months with MCF (P = .315); at 1 year, 40.2% (95% CI, 34% to 46%) of ECF and 32.7% (95% CI, 27% to 38%) of MCF patients were alive. Median failure-free survival was 7 months with both regimens. Global QOL scores were better with ECF at 3 and 6 months. CONCLUSION: This study confirms response, survival, and QOL benefits of ECF observed in a previous randomized study. The equivalent efficacy of MCF was demonstrated, but QOL was superior with ECF. ECF remains one of the reference treatments for advanced esophagogastric cancer.


2019 ◽  
Vol 24 (10) ◽  
pp. 504-514
Author(s):  
Rosa Leedham ◽  
Kate L White ◽  
David Yates ◽  
Lauren Brown

Objectives: The aim of the study was to evaluate the analgesia and recovery effects of two doses (0.12 mg/kg and 0.24 mg/kg) of subcutaneous buprenorphine in cats undergoing ovariohysterectomy. Methods: This was an assessor-blinded, randomised, clinical study. A total of 83 cats were recruited and randomly allocated to receive 0.12 mg/kg buprenorphine or 0.24 mg/kg buprenorphine subcutaneously, followed 30 minutes later by 40 μg/kg medetomidine intramuscularly. Anaesthesia was induced with intravenous alfaxalone to effect and maintained with isoflurane in oxygen. All cats received meloxicam before surgery. Temperament score, quality of sedation, induction of anaesthesia, dose of alfaxalone and recovery were scored using simple descriptive scales. Atipamazole was administered following surgery. Physiological variables during anaesthesia were recorded. Cats were assessed postoperatively by the same blinded observer at 2, 4 and 24 hours using a modified Colorado Feline Acute Pain scale. The presence or absence of mydriasis was noted. Results: No significant differences were identified between groups. Three cats in the 0.12 mg/kg group and four in the 0.24 mg/kg group required rescue analgesia. Mydriasis persisting for at least 24 hours was evident in 75 cats. Conclusions and relevance: No differences in analgesia were detected between groups with these protocols; mydriasis was common in both groups.


2003 ◽  
Vol 37 (2) ◽  
pp. 202-205 ◽  
Author(s):  
Patrick G Clay ◽  
Molly M Adams

OBJECTIVE: To report a case of Parkinson-like symptoms appearing in a patient after introduction of ritonavir to buspirone therapy. CASE SUMMARY: A 54-year-old HIV-positive white man presented to the clinic with a 2-week history of ataxia, shuffling gait, cogwheel rigidity, resting tremor, and sad affect with masked features. This patient had been receiving high-dose buspirone (40 mg every morning and 30 mg every evening) for 2 years prior to the introduction of ritonavir/indinavir combination therapy (400 mg/400 mg twice daily) 6 weeks prior to initiation of the above symptoms. Buspirone was decreased to 15 mg 3 times daily, ritonavir/indinavir was discontinued, and amprenavir 1200 mg twice daily was added. The patient's symptoms began to subside after 1 week, with complete resolution after about 2 weeks. The patient continued to receive buspirone for an additional 12 months without recurrence of symptoms. DISCUSSION: This is the first reported interaction of buspirone and antiretrovirals. Buspirone, extensively metabolized by CYP3A4, was likely at supratherapeutic levels due to the inhibitory effect of ritonavir and, secondarily, indinavir. The Parkinson-like symptoms developed rapidly and severely, impacted this patient's quality of life, and necessitated significant clinic expenditures to identify this drug–drug interaction. CONCLUSIONS: This case demonstrates a severe drug–drug interaction between buspirone and ritonavir and further demonstrates the need for awareness of the metabolic profile for all agents an HIV-infected patient is receiving.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1297.2-1297
Author(s):  
J. Protudjer ◽  
C. Billedeau ◽  
C. Stavropoulou ◽  
A. Cholakis ◽  
R. Schroth ◽  
...  

Background:Rates of periodontal disease and tooth loss are increased in rheumatoid arthritis (RA). Periodontal disease may exacerbate RA inflammation and complicate RA care. Understanding factors that contribute to the increased burden of periodontal disease in RA is critical to improving oral health and possibly arthritis outcomes. People with RA may have unique needs and/or barriers to maintain oral health.Objectives:To determine from people with RA what are their experiences and perceptions about their oral health, their most important questions relating to oral health, and how they wish to receive oral health information.Methods:Semi-structured interviews were conducted with RA patients. Recorded interview transcripts underwent iterative content analysis. Transcripts were initially reviewed to develop a coding guide. Latent content, or larger themes, were then applied to the transcripts. Constructs were considered saturated when no new themes were identified with subsequent interviews. We report identified themes with representative quotes.Results:Interviews with 11 RA (10[91%] female; all on RA medication) averaged 19 minutes (range 8-31 minutes) and were mostly conducted face-to-face. Many believed RA medication contributed to dry mouth. Most participants had not previously considered other links between oral health and RA. Themes identified included the need for complicated oral health routines, barriers of cost and access to dental care, and shame relating to oral health (Table 1). Participants preferred to receive oral health education from their rheumatologists or dentists over printed or online resources.Conclusion:RA patients have unique needs relating to oral health and report poor oral quality of life. Strategies to optimize oral health in RA may include educational tools for optimizing oral self-care appropriate for RA, and improved access to oral care professionals who are aware of the needs of arthritis patients.Disclosure of Interests:Jennifer Protudjer: None declared, Corrie Billedeau: None declared, Chrysi Stavropoulou: None declared, Anastasia Cholakis: None declared, Robert Schroth: None declared, Carol Hitchon Grant/research support from: UCB Canada; Pfizer Canada


2021 ◽  
Vol 11 (14) ◽  
pp. 6401
Author(s):  
Kateryna Czerniachowska ◽  
Karina Sachpazidu-Wójcicka ◽  
Piotr Sulikowski ◽  
Marcin Hernes ◽  
Artur Rot

This paper discusses the problem of retailers’ profit maximization regarding displaying products on the planogram shelves, which may have different dimensions in each store but allocate the same product sets. We develop a mathematical model and a genetic algorithm for solving the shelf space allocation problem with the criteria of retailers’ profit maximization. The implemented program executes in a reasonable time. The quality of the genetic algorithm has been evaluated using the CPLEX solver. We determine four groups of constraints for the products that should be allocated on a shelf: shelf constraints, shelf type constraints, product constraints, and virtual segment constraints. The validity of the developed genetic algorithm has been checked on 25 retailing test cases. Computational results prove that the proposed approach allows for obtaining efficient results in short running time, and the developed complex shelf space allocation model, which considers multiple attributes of a shelf, segment, and product, as well as product capping and nesting allocation rule, is of high practical relevance. The proposed approach allows retailers to receive higher store profits with regard to the actual merchandising rules.


2021 ◽  
pp. 1098612X2199615
Author(s):  
Emily P Wheeler ◽  
Amanda L Abelson ◽  
Jane C Lindsey ◽  
Lois A Wetmore

Objectives The aim of this pilot study was to compare the quality of sedation and ease of intravenous (IV) catheter placement following sedation using two intramuscular (IM) sedation protocols in cats: hydromorphone, alfaxalone and midazolam vs hydromorphone and alfaxalone. Methods This was a prospective, randomized and blinded study. Cats were randomly assigned to receive an IM injection of hydromorphone (0.1 mg/kg), alfaxalone (1.5 mg/kg) and midazolam (0.2 mg/kg; HAM group), or hydromorphone (0.1 mg/kg) and alfaxalone (1.5 mg/kg; HA group). Sedation scoring (0–9, where 9 indicated maximum sedation) was performed at 0, 5, 10, 15 and 20 mins from the time of injection. At 20 mins, an IV catheter placement score (0–10, where 10 indicated least resistance) was performed. Results Twenty-one client-owned adult cats were included in this study. Sedation and IV catheter placement scores were compared between groups using Wilcoxon rank sum tests. Peak sedation was significantly higher ( P = 0.002) in the HAM group (median 9; range 7–9) than in the HA group (median 7; range 3–9), and IV catheter placement scores were significantly higher ( P = 0.001) in the HAM group (median 9.5; range 7–10) compared with the HA group (median 7; range 4–9). Spearman correlations were calculated between IV catheter placement score and sedation scores. There was a significant positive correlation of average sedation over time (correlation 0.83; P <0.001) and sedation at 20 mins (correlation 0.76; P <0.001) with a higher, more favorable IV catheter placement score. Conclusions and relevance These preliminary results suggest that the addition of midazolam to IM alfaxalone and hydromorphone produced more profound sedation and greater ease of IV catheter placement than IM alfaxalone and hydromorphone alone.


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