On the waiting time of a two-stage queueing system with blocking

1984 ◽  
Vol 21 (3) ◽  
pp. 628-638 ◽  
Author(s):  
Christos Langaris ◽  
Brian Conolly
Keyword(s):  
Waiting Time ◽  
Extensive Study ◽  
Careful Study ◽  
Two Stage ◽  
Waiting Time Process ◽  
Numerical Effect ◽  
Stage 1 ◽  
High Degree ◽  
Service Channels ◽  
Effective Service

An analysis is given of the first-come-first-served waiting-time process in stages 1 and 2 of a two-stage service system with k and n parallel service channels in the first and second stages respectively, and m intermediate waiting places (k, n ≧ 1, m ≧ 0).Although the method of analysis is straightforward the details are intricate and require careful study of the location of the zeros of a high-degree polynomial.The analysis paves the way for an extensive study of the numerical effect on waiting time of blocking in commonly encountered systems of this nature. ‘Effective service time' in stage 1, defined so as to include blocked time, is considered separately.

On the waiting time of a two-stage queueing system with blocking

1984 ◽  
Vol 21 (03) ◽  
pp. 628-638 ◽  
Author(s):  
Christos Langaris ◽  
Brian Conolly
Keyword(s):  
Waiting Time ◽  
Extensive Study ◽  
Careful Study ◽  
Two Stage ◽  
Waiting Time Process ◽  
Numerical Effect ◽  
Stage 1 ◽  
High Degree ◽  
Service Channels ◽  
Effective Service

An analysis is given of the first-come-first-served waiting-time process in stages 1 and 2 of a two-stage service system with k and n parallel service channels in the first and second stages respectively, and m intermediate waiting places (k, n ≧ 1, m ≧ 0). Although the method of analysis is straightforward the details are intricate and require careful study of the location of the zeros of a high-degree polynomial. The analysis paves the way for an extensive study of the numerical effect on waiting time of blocking in commonly encountered systems of this nature. ‘Effective service time' in stage 1, defined so as to include blocked time, is considered separately.

On the service time distribution and the waiting time process of a potentially infinite capacity queueing system

1969 ◽  
Vol 6 (3) ◽  
pp. 594-603 ◽  
Author(s):  
Nasser Hadidi
Keyword(s):  
Waiting Time ◽  
Service Time ◽  
Time Distribution ◽  
Queueing System ◽  
Service Time Distribution ◽  
Waiting Time Distribution ◽  
Poisson Stream ◽  
Waiting Time Process ◽  
The Subject ◽  
Effective Service

In [1] the authors dealt with a particular queueing system in which arrivals occurred in a Poisson stream and the probability differential of a service completion was μσn when the queue contained n customers. Much of the theory could not be carried out further analytically for a general σn, which is a purely n-dependent quantity. To carry the analysis further to the extent of finding the “effective” service time and the waiting time distribution when σn is a linear function of n, (which is considered to be rather general and sufficient for practical purposes), constitutes the subject matter of this paper.

Demonstration of Pharmacokinetic and Pharmacodynamic Equivalence in Healthy Volunteers for B12019, a New Proposed Pegfilgrastim Biosimilar

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5079-5079 ◽  
Author(s):  
Karsten Roth ◽  
Barbara Gastl ◽  
Dirk Lehnick ◽  
Karin Jacob ◽  
Ruediger Jankowsky
Keyword(s):  
Geometric Mean ◽  
Area Under The Curve ◽  
Two Stage ◽  
Acceptance Criteria ◽  
Double Blind ◽  
Clinical Level ◽  
Effect Curve ◽  
Long Acting ◽  
Stage 1 ◽  
High Degree

Abstract B12019 is being developed as a biosimilar to Neulasta® (INN pegfilgrastim), a long-acting, pegylated form of recombinant human granulocyte-colony stimulating factor (r-metHuG-CSF, INN filgrastim) for the prevention of chemotherapy-induced neutropenia. A comprehensive analytical, functional and preclinical comparability program has already demonstrated a high degree of similarity of B12019 as compared to Neulasta®. In order to confirm the similarity on the clinical level, a pharmacokinetics/pharmacodynamics (PK/PD) study was conducted with B12019 in comparison to EU-authorised Neulasta®. The study was designed as a single-dose, randomized, double-blind, two-way crossover study. The study statistics were based on a two-stage design derived from to Potvin et al, 2007 to address potential high variability for the PK endpoints. 172 healthy male volunteers were enrolled in stage 1 of the study, whereas stage 2 would allow the recruitment of additional 102 subjects. The subjects received B12019 as well as Neulasta®. The primary PK endpoints were the Area Under the Curve for concentration (AUC0-last) and maximum concentration (Cmax). The primary PD endpoint was the Area Under the Effect Curve (AUEC) for Absolute Neutrophil Count (ANC). PK endpoints were assessed with a 94.32% confidence interval (CI) accounting for the two-stage study design, whereas the PD endpoint was assessed with a 95% CI. Furthermore, safety and immunogenicity were investigated. 161 subjects were eligible to contribute to the model-based PK and PD comparison based upon the first stage of the study. For the PK endpoints, the 94.32% CIs for the geometric mean ratios were 86.60-104.73% for AUC0-last and 84.36-102.18% for Cmax. Both PK endpoints fulfilled the predefined acceptance criteria of being within the range of 80-125%. For the PD endpoint, the 95% CI for the geometric mean ratio of the ANC AUEC was 98.67-101.75%, also falling within the predefined acceptance criteria of 80-125%. Since the primary PK endpoints were met in stage 1 of the study, stage 2 was not required. The safety profile of B12019 did not show any clinically meaningful difference as compared to Neulasta®. Neither anti-G-CSF nor neutralising antibodies were detected for both, B12019 and Neulasta®. The study demonstrated PK and PD comparability as well as comparable safety and immunogenicity profiles of B12019 as compared to EU-authorised Neulasta®. No clinically meaningful differences were detected between B12019 and Neulasta®. The high analytical and functional similarity of B12019 was confirmed on clinical level. Disclosures Roth: Cinfa Biotech: Employment. Gastl:Cinfa Biotech: Consultancy. Lehnick:Nuvisan GmbH: Employment. Jacob:Cinfa Biotech: Employment. Jankowsky:Cinfa Biotech: Employment.

On the service time distribution and the waiting time process of a potentially infinite capacity queueing system

1969 ◽  
Vol 6 (03) ◽  
pp. 594-603 ◽  
Author(s):  
Nasser Hadidi
Keyword(s):  
Waiting Time ◽  
Service Time ◽  
Time Distribution ◽  
Queueing System ◽  
Service Time Distribution ◽  
Waiting Time Distribution ◽  
Poisson Stream ◽  
Waiting Time Process ◽  
The Subject ◽  
Effective Service

In [1] the authors dealt with a particular queueing system in which arrivals occurred in a Poisson stream and the probability differential of a service completion was μσn when the queue contained n customers. Much of the theory could not be carried out further analytically for a general σn , which is a purely n-dependent quantity. To carry the analysis further to the extent of finding the “effective” service time and the waiting time distribution when σn is a linear function of n, (which is considered to be rather general and sufficient for practical purposes), constitutes the subject matter of this paper.

A two-stage design optimization framework for multifield origami-inspired structures

2021 ◽  
pp. 1045389X2110116
Author(s):  
Wei Zhang ◽  
Saad Ahmed ◽  
Jonathan Hong ◽  
Zoubeida Ounaies ◽  
Mary Frecker
Keyword(s):  
Case Studies ◽  
Computing Time ◽  
Computational Cost ◽  
High Fidelity ◽  
Fe Model ◽  
Two Stage ◽  
Baseline Design ◽  
Optimization Framework ◽  
Highly Nonlinear ◽  
Stage 1

Different types of active materials have been used to actuate origami-inspired self-folding structures. To model the highly nonlinear deformation and material responses, as well as the coupled field equations and boundary conditions of such structures, high-fidelity models such as finite element (FE) models are needed but usually computationally expensive, which makes optimization intractable. In this paper, a computationally efficient two-stage optimization framework is developed as a systematic method for the multi-objective designs of such multifield self-folding structures where the deformations are concentrated in crease-like areas, active and passive materials are assumed to behave linearly, and low- and high-fidelity models of the structures can be developed. In Stage 1, low-fidelity models are used to determine the topology of the structure. At the end of Stage 1, a distance measure [Formula: see text] is applied as the metric to determine the best design, which then serves as the baseline design in Stage 2. In Stage 2, designs are further optimized from the baseline design with greatly reduced computing time compared to a full FEA-based topology optimization. The design framework is first described in a general formulation. To demonstrate its efficacy, this framework is implemented in two case studies, namely, a three-finger soft gripper actuated using a PVDF-based terpolymer, and a 3D multifield example actuated using both the terpolymer and a magneto-active elastomer, where the key steps are elaborated in detail, including the variable filter, metrics to select the best design, determination of design domains, and material conversion methods from low- to high-fidelity models. In this paper, analytical models and rigid body dynamic models are developed as the low-fidelity models for the terpolymer- and MAE-based actuations, respectively, and the FE model of the MAE-based actuation is generalized from previous work. Additional generalizable techniques to further reduce the computational cost are elaborated. As a result, designs with better overall performance than the baseline design were achieved at the end of Stage 2 with computing times of 15 days for the gripper and 9 days for the multifield example, which would rather be over 3 and 2 months for full FEA-based optimizations, respectively. Tradeoffs between the competing design objectives were achieved. In both case studies, the efficacy and computational efficiency of the two-stage optimization framework are successfully demonstrated.

scholarly journals Extensive, Nonrandom Diversity of Excision Footprints Generated by Ds-Like Transposon Ascot-1Suggests New Parallels with V(D)J Recombination

1998 ◽  
Vol 18 (7) ◽  
pp. 4337-4346 ◽  
Author(s):  
Vincent Colot ◽  
Vicki Haedens ◽  
Jean-Luc Rossignol
Keyword(s):  
Extensive Study ◽  
Empty Site ◽  
Site Factors ◽  
Original Sequence ◽  
Ascobolus Immersus ◽  
High Degree ◽  
Hairpin Formation ◽  
Processing Steps ◽  
Color Gene

ABSTRACT Upon insertion, transposable elements can disrupt or alter gene function in various ways. Transposons moving through a cut-and-paste mechanism are in addition often mutagenic when excising because repair of the empty site seldom restores the original sequence. The characterization of numerous excision events in many eukaryotes indicates that transposon excision from a given site can generate a high degree of DNA sequence and phenotypic variation. Whether such variation is generated randomly remains largely to be determined. To this end, we have exploited a well-characterized system of genetic instability in the fungus Ascobolus immersus to perform an extensive study of excision events. We show that this system, which produces many phenotypically and genetically distinct derivatives, results from the excision of a novel Ds-like transposon,Ascot-1, from the spore color gene b2. A unique set of 48 molecularly distinct excision products were readily identified from a representative sample of excision derivatives. Products varied in their frequency of occurrence over 4 orders of magnitude, yet most showed small palindromic nucleotide additions. Based on these and other observations, compelling evidence was obtained for intermediate hairpin formation during the excision reaction and for strong biases in the subsequent processing steps at the empty site. Factors likely to be involved in these biases suggest new parallels between the excision reaction performed by transposons of thehAT family and V(D)J recombination. An evaluation of the contribution of small palindromic nucleotide additions produced by transposon excision to the spectrum of spontaneous mutations is also presented.

A Rational Reconstruction of Expert Judgments in Organ Allocation

2001 ◽  
Vol 23 (2) ◽  
Author(s):  
Adele Diederich
Keyword(s):  
Waiting Time ◽  
German Law ◽  
Organ Allocation ◽  
International Exchange ◽  
Simulation Studies ◽  
Allocation System ◽  
Kidney Allocation System ◽  
Time Distance ◽  
Computer Simulation Studies ◽  
High Degree

AbstractThe Eurotransplant Kidney Allocation System (ETKAS) emerged from the XCOMB model by Wujciak and Opelz (1993a,b), who applied computer simulation studies to create an allocation algorithm. The present study investigated how experts would allocate a donated organ to patients on the waiting list with respect to the five allocation factors proposed in the ETKAS (number of mismatches, mismatch probability, waiting time, distance, international exchange balance). The experts’ evaluations were compared to the ETKAS points as well as to factor weights established in mandatory allocation guidelines which are based on the German law for organ allocation (Transplantationsgesetz). The investigation was carried out using a conjoint analysis. Overall, the results indicate a fairly high degree of agreement between the experts’ opinions and the existing allocation system ETKAS and even more so for the allocation guidelines, in particular, with respect to the factors Mismatches, Mismatch probability, and Waiting time.

scholarly journals Design of an economically feasible support for the replacement of pillars in Providencia Mine, Antioquia - Stage 1

2019 ◽  
Vol 28 (51) ◽  
pp. 89-104
Author(s):  
Claudia Yasmin Montaño-Chinchilla ◽  
Jorge Martin Molina-Escobar ◽  
Ludger Oswaldo Suarez-Burgos ◽  
Elkin De Jesús Ceballos-Guerra
Keyword(s):  
Safety Factor ◽  
Gold Mining ◽  
Economic Value ◽  
Cost Benefit ◽  
Cost Benefit Ratio ◽  
Mining Works ◽  
Stage 1 ◽  
High Degree ◽  
Continuous Field ◽  
Safety And Stability

Pillar replacement in mining works is a technique of using the pillars that are part of the support structures having a high degree of mineralization, which attracts economic interest. The technique consists of replacing the support pillars of the mineral matrix that contain appreciable and beneficial quantities of mineral by artificial pillars that provide geomechanical structure to the operations, generating support and safety benefits greater than or equal to those provided by the original pillars and thus maximizing the intrinsic economic value of the available rock in the operation. Based on the literature regarding design techniques for the assembly of pillars used in underground gold mining, daily and continuous field inspections were conducted for two months, taking the necessary data for the proposed design following ISRM standards for data collection. The proposed pillars must consider a set of operational economic requirements and meet the geomechanical performance required to guarantee the safety and stability of the site. The design consisted of a combination of two types of pillars, one of concrete and one of mesh, cables and sterile material (granodiorite and dyke). The measurements consisted of RMR determination, the dimensions of the current pillars, and the geomechanical condition using detailed scanlines. Subsequently, the information was refined and correlated, and the degree of fracture and safety factor of the original pillars versus those proposed in the new designs were calculated. As a result, the optimal design for the construction of the replacement pillars should have dimensions of 2 x 1.7 x 1.7 meters, achieving a safety factor of 1.36, complying with the geomechanical requirements of safety and stability and yielding a profit of 405 % as a cost-benefit ratio in replacing the original pillars by those proposed in the design; the sterile material and mesh pillars would have dimensions of 2 x 2 x 2 meters.

scholarly journals Acceptance of Teledermoscopy by General Practitioners and Dermatologists in Denmark

2021 ◽  
pp. e2021033
Author(s):  
Tine Vestergaard ◽  
Merethe K. Andersen ◽  
Anette Bygum
Keyword(s):  
General Practitioners ◽  
Waiting Time ◽  
Response Rate ◽  
Previous Experience ◽  
Face To Face ◽  
Skin Cancers ◽  
Management Plans ◽  
Degree Of Acceptance ◽  
High Degree

Background: Teledermoscopy can be used to triage referrals of suspected skin cancers, thereby reducing waiting time and number of face-to-face consultations with a dermatologist. However, the success of the implementation of this technology in part relies on the acceptance of the providers. Objectives: This study assessed the attitudes towards teledermoscopy of referring general practitioners and consultant dermatologists. Methods: General practitioners from 48 practices and 3 dermatologists in the region of Southern Denmark, who had previous experience with teledermoscopy, were invited to answer questionnaires on their acceptance of the technology. Results: General practitioners from 23 practices responded. All domains of the questionnaire received high scores, indicating a high degree of acceptance of teledermoscopy among respondents. All 3 dermatologists agreed that teledermoscopy was useful for triaging referrals, but they were less confident in their diagnoses and management plans proposed by teledermoscopy than in traditional face-to-face evaluations of patients. Two of the 3 dermatologists were satisfied with using teledermoscopy as a consult method. Conclusions: This study reports high levels of provider acceptance of teledermoscopy. However, a low response rate among general practitioners may limit its generalizability.

Sign in / Sign up

Export Citation Format

Share Document