Search results for "Lead time"
showing 10 items of 15 documents
Characteristics and Clinical Outcome of Breast Cancer Patients with Asymptomatic Brain Metastases
2020
Background: Brain metastases (BM) have become a major challenge in patients with metastatic breast cancer. Methods: The aim of this analysis was to characterize patients with asymptomatic BM (n = 580) in the overall cohort of 2589 patients with BM from our Brain Metastases in Breast Cancer Network Germany (BMBC) registry. Results: Compared to symptomatic patients, asymptomatic patients were slightly younger at diagnosis (median age: 55.5 vs. 57.0 years, p = 0.01), had a better performance status at diagnosis (Karnofsky index 80&ndash
Threshold rule and scaling behavior in a multi-agent supply chain
2010
In this paper an agent-based model of self organized criticality is developed in a network economy characterized by lead time and a threshold behavior of firms. Instead of considering the aggregate production of the economy as a whole, we focus on both the propagation and amplification effects of a demand shock in the sectorial productions of a multi-agent supply chain. We study a static network structure representing a relation of firms in a lower-upper stream in an industrial organization. In our model, the individual (R, nQ) policies play an important role in generating a propagation effect across the different layers of the economy, and the propagation turns into the large fluctuations …
Assessing the predictability of Medicanes in ECMWF ensemble forecasts using an object-based approach
2018
The predictability of eight southern European tropical-like cyclones, seven of which Medicanes, is studied evaluating ECMWF operational ensemble forecasts against operational analysis data. Forecast cyclone trajectories are compared to the cyclone trajectory in the analysis by means of a dynamic time warping technique, which allows to find a match in terms of their overall spatio-temporal similarity. Each storm is treated as an object and its forecasts are analysed using metrics that describe intensity, symmetry, compactness, and upper-level thermal structure. This object-based approach allows to focus on specific storm features, while tolerating their shifts in time and space to some exten…
The 1-way on-line coupled atmospheric chemistry model system MECO(n) – Part 3: Meteorological evaluation of the on-line coupled system
2012
Abstract. Three detailed meteorological case studies are conducted with the global and regional atmospheric chemistry model system ECHAM5/MESSy(→COSMO/MESSy)n, shortly named MECO(n), in order to assess the general performance of the on-line coupling of the regional model COSMO to the global model ECHAM5. The cases are characterised by intense weather systems in Central Europe: an intense cold frontal passage in March 2010, a convective frontal event in July 2007, and the high impact winter storm "Kyrill" in January 2007. Simulations are performed with the new on-line-coupled model system and compared to classical, off-line COSMO hindcast simulations driven by ECMWF analyses. Precipitation o…
Lean Internal Startups for Software Product Innovation in Large Companies: Enablers and Inhibitors
2018
Context: Startups are disrupting traditional markets and replacing well-established actors with their innovative products.To compete in this age of disruption, large and established companies cannot rely on traditional ways of advancement, which focus on cost efficiency, lead time reduction and quality improvement. Corporate management is now looking for possibilities to innovate like startups. Along with it, the awareness and the use of the Lean startup approach have grown rapidly amongst the software startup community and large companies in recent years. Objective: The aim of this study is to investigate how Lean internal startup facilitates software product innovation in large companies.…
On the Bullwhip Avoidance Phase: The Synchronised Supply Chain
2012
Abstract The aim of this paper is to analyse the operational response of a Synchronised Supply Chain (SSC). To do so, first a new mathematical model of a SSC is presented. An exhaustive Latin Square design of experiments is adopted in order to perform a boundary variation analysis of the main three parameters of the periodic review smoothing ( S , R ) order-up-to policy: i.e., lead time, demand smoothing forecasting factor, and proportional controller of the replenishment rule. The model is then evaluated under a variety of performance measures based on internal process benefits and customer benefits. The main results of the analysis are: (I) SSC responds to violent changes in demand by re…
Estimation of lead-time bias and its impact on the outcome of surveillance for the early diagnosis of hepatocellular carcinoma.
2014
Lead-time is the time by which diagnosis is anticipated by screening/surveillance with respect to the symptomatic detection of a disease. Any screening program, including surveillance for hepatocellular carcinoma (HCC), is subject to lead-time bias. Data regarding lead-time for HCC are lacking. Aims of the present study were to calculate lead-time and to assess its impact on the benefit obtainable from the surveillance of cirrhotic patients. Background & Aims: Lead-time is the time by which diagnosis is anticipated by screening/surveillance with respect to the symptomatic detection of a disease. Any screening program, including surveillance for hepatocellular carcinoma (HCC), is subject to …
Methodological Approach to Studying the dynamics of production networks: a Discrete Event Simulation Model
2013
This paper shows how discrete-event simulation represents an appropriate tool for approaching the dynamics of production networks. Three important factors influencing production network dynamics, specifically finite production capacity, manufacturing lead time, and its variability are discussed and a basic discrete-event simulation model is presented. Such model, which in its basic form represents a simple retail/distribution two-stage supply chain, is then extended in order to take into account those factors that can not be included in a classical control theoretical model.
Interactive Multiobjective Optimization in Lot Sizing with Safety Stock and Safety Lead Time
2021
In this paper, we integrate a lot sizing problem with the problem of determining optimal values of safety stock and safety lead time. We propose a probability of product availability formula to assess the quality of safety lead time and a multiobjective optimization model as an integrated lot sizing problem. In the proposed model, we optimize six objectives simultaneously: minimizing purchasing cost, ordering cost, holding cost and, at the same time, maximizing cycle service level, probability of product availability and inventory turnover. To present the applicability of the proposed model, we consider a real case study with data from a manufacturing company and apply the interactive NAUTI…
Avoiding Demand Amplification Phenomenon via Hi-tech Application: A What-If Supply Chain Analysis
2010
The well-known deleterious effect of the amplification of variance of order rates in multi-echelon systems, commonly known as demand amplification phenomenon or bullwhip effect, still presents new challenges and continues to fascinate the operations management community. Recently this research field is focusing on the study of robustness of bullwhip avoidance techniques under uncertainty, as environmental conditions often determine variations in processes, with regards to production and delivery lead time, and variations in the parameters of the decision policies. This work aims at quantifying the efficacy of bullwhip dampening techniques and at verifying this efficacy against variations in…