scholarly journals Computer Assisted Localization of a Heart Arrhythmia

2018 ◽  
Author(s):  
Chris Vogl ◽  
Peng Zheng ◽  
Stephen P. Seslar ◽  
Aleksandr Y. Aravkin
Keyword(s):  
Diagnostic Procedure ◽  
Feasibility Problem ◽  
Computer Assisted ◽  
Optimization Approach ◽  
Arrival Times ◽  
Heart Arrhythmia ◽  
Simulation Based ◽  
Heart Anatomy ◽  
Using Data ◽  
Diagnostic Catheter

AbstractWe consider the problem of locating a point-source heart arrhythmia using data from a standard diagnostic procedure, where a reference catheter is placed in the heart, and arrival times from a second diagnostic catheter are recorded as the diagnostic catheter moves around within the heart.We model this situation as a nonconvex feasibility problem, where given a set of arrival times, we look for a source location that is consistent with the available data. We develop a new optimization approach and fast algorithm to obtain online proposals for the next location to suggest to the operator as she collects data. We validate the procedure using a Monte Carlo simulation based on patients’ electrophysiological data. The proposed procedure robustly and quickly locates the source of arrhythmias without any prior knowledge of heart anatomy.

scholarly journals A Simulation-Based Optimization Approach for Integrated Port Resource Allocation Problem

2014 ◽  
Vol 26 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Gholamreza Ilati ◽  
Abdorreza Sheikholeslami ◽  
Erfan Hassannayebi
Keyword(s):  
Objective Function Value ◽  
Operating Cost ◽  
Allocation Problem ◽  
Container Terminals ◽  
Optimization Approach ◽  
Berth Allocation ◽  
Arrival Times ◽  
Simulation Based ◽  
Simulation Based Optimization ◽  
Tidal Variations

Todays, due to the rapid increase in shipping volumes, the container terminals are faced with the challenge to cope with these increasing demands. To handle this challenge, it is crucial to use flexible and efficient optimization approach in order to decrease operating cost. In this paper, a simulation-based optimization approach is proposed to construct a near-optimal berth allocation plan integrated with a plan for tug assignment and for resolution of the quay crane re-allocation problem. The research challenges involve dealing with the uncertainty in arrival times of vessels as well as tidal variations. The effectiveness of the proposed evolutionary algorithm is tested on RAJAEE Port as a real case. According to the simulation result, it can be concluded that the objective function value is affected significantly by the arrival disruptions. The result also demonstrates the effectiveness of the proposed simulation-based optimization approach.

scholarly journals Enhanced coverage by integrating site interdependencies in capacitated EMS location models

2021 ◽  
Author(s):  
Matthias Grot ◽  
Tristan Becker ◽  
Pia Mareike Steenweg ◽  
Brigitte Werners
Keyword(s):  
Discrete Event ◽  
Mathematical Formulation ◽  
Optimization Approach ◽  
Solution Quality ◽  
Similar System ◽  
Event Simulation ◽  
Simulation Based ◽  
Average System ◽  
Simplifying Assumptions ◽  
A Site

AbstractIn order to allocate limited resources in emergency medical services (EMS) networks, mathematical models are used to select sites and their capacities. Many existing standard models are based on simplifying assumptions, including site independency and a similar system-wide busyness of ambulances. In practice, when a site is busy, a call is forwarded to another site. Thus, the busyness of each site depends not only on the rate of calls in the surrounding area, but also on interactions with other facilities. If the demand varies across the urban area, assuming an average system-wide server busy fraction may lead to an overestimation of the actual coverage. We show that site interdependencies can be integrated into the well-known Maximum Expected Covering Location Problem (MEXCLP) by introducing an upper bound for the busyness of each site. We apply our new mathematical formulation to the case of a local EMS provider. To evaluate the solution quality, we use a discrete event simulation based on anonymized real-world call data. Results of our simulation-optimization approach indicate that the coverage can be improved in most cases by taking site interdependencies into account, leading to an improved ambulance allocation and a faster emergency care.

Hybrid simulation based optimization approach for supply chain management

2012 ◽  
Vol 47 ◽  
pp. 183-193 ◽  
Author(s):  
Amalia Nikolopoulou ◽  
Marianthi G. Ierapetritou
Keyword(s):  
Supply Chain ◽  
Supply Chain Management ◽  
Hybrid Simulation ◽  
Optimization Approach ◽  
Chain Management ◽  
Simulation Based ◽  
Simulation Based Optimization

Adaptive PPS durch simulationsbasierte Optimierung*/Adaptive PPC by simulation-based optimization

2017 ◽  
Vol 107 (04) ◽  
pp. 288-292
Author(s):  
M. Kück ◽  
J. Ehm ◽  
T. Hildebrandt ◽  
M. Prof. Freitag ◽  
E. M. Prof. Frazzon
Keyword(s):  
Job Shop ◽  
Job Shop Scheduling ◽  
Production Systems ◽  
Semiconductor Industry ◽  
Small Scale ◽  
Planning Problem ◽  
Optimization Approach ◽  
Flexible Production Systems ◽  
Simulation Based ◽  
Simulation Based Optimization

Der Trend zur Fertigung individualisierter Produkte in kleinen Losgrößen erfordert hochflexible Produktionssysteme. Durch die damit verbundene Systemdynamik wird die Reihenfolgeplanung zu einem komplexen Planungsproblem. Der Beitrag beschreibt ein simulationsbasiertes Optimierungsverfahren, welches Echtzeitinformationen zur adaptiven Selektion geeigneter Prioritätsregeln verwendet. Das Potenzial des Ansatzes wird anhand eines Anwendungsfalls aus der Halbleiterindustrie demonstriert.   The trend to manufacturing individualized products in small-scale series demands highly flexible production systems. Because of the dynamic nature of such production systems, scheduling becomes a complex planning problem with frequent need for rescheduling. This article describes a data-driven simulation-based optimization approach using real-time information for adaptive job shop scheduling. The potential of the approach is demonstrated by a use case from semiconductor industry.

Simulationsbasierte Optimierung von Fabrikabläufen*/Simulation-based optimization of factory processes

2018 ◽  
Vol 108 (04) ◽  
pp. 221-227
Author(s):  
T. Donhauser ◽  
L. Baier ◽  
T. Ebersbach ◽  
J. Franke ◽  
P. Schuderer
Keyword(s):  
Calcium Silicate ◽  
Optimization Approach ◽  
Process Technology ◽  
High Quality ◽  
Decomposition Approach ◽  
Planning And Control ◽  
Simulation Based ◽  
Simulation Based Optimization ◽  
And Control

Die Kalksandsteinherstellung weist aufgrund prozesstechnisch und zeitlich divergierender Teilprozesse einen hohen Planungs- sowie Steuerungsaufwand auf. Durch Einsatz eines simulationsgestützten Optimierungsverfahrens kann diese Komplexität bewältigt werden. Um bei hoher Lösungsqualität eine Laufzeit zu erreichen, die einen operativen Einsatz des Verfahrens gestattet, wird auf Basis einer vorangegangenen Studie ein Dekompositionsansatz implementiert und dessen Eignung durch Testläufe validiert.   Calcium silicate masonry production requires a great deal of planning and control due to the fact that subprocesses vary in terms of process technology and time. To overcome this complexity, a simulation-based optimization approach is applied. As a short runtime that allows the method to be used operationally and yet still offers a high quality of solution is crucial, a decomposition approach is implemented on the basis of a previous study and its suitability is validated by means of test runs.

A Suggestion for an Effective Use of a Computer-aided Diagnosis System in Screening for Hyperthyroidism

1977 ◽  
Vol 16 (02) ◽  
pp. 93-95 ◽  
Author(s):  
A. Alpérovitch ◽  
P. Fragu
Keyword(s):  
Clinical Signs ◽  
Test Sample ◽  
Bayes Theorem ◽  
Computer Assisted ◽  
Thyroid Status ◽  
Screening Strategies ◽  
Computer Aided ◽  
Using Data ◽  
Effective Use ◽  
Aided Diagnosis

A computer-assisted program for diagnosing hyperthyroidism, specially devoted to the screening of functional thyroid status, has been written using data provided by 359 patients, 282 euthyroid and 77 hyperthyroid. The model is based on Bayes’ theorem.Using only 9 clinical signs and the free thyroxin index, the program achieved, on a test-sample of 117 new patients, an overall accuracy of 90% ; 10% of the cases were in the zone of uncertainty, and none was misdiagnosed.Different screening strategies are examined and their results discussed.

Identifying Program Preferences through Conjoint Analysis: Illustrative Results from a Parent Sample

1993 ◽  
Vol 8 (2) ◽  
pp. 124-133 ◽  
Author(s):  
Richard Spoth ◽  
Cleve Redmond
Keyword(s):  
Conjoint Analysis ◽  
Computer Simulations ◽  
Prevention Programs ◽  
Computer Assisted ◽  
Cross Sectional ◽  
Telephone Interviews ◽  
Relative Value ◽  
Individual Features ◽  
Parent Choices ◽  
Using Data

Purpose. The purpose of this article is to illustrate the application of conjoint analysis, a consumer research technique, using data from a survey of parents' preferences for prevention programs. Design. This study utilized a one-time, cross-sectional telephone survey. Setting. Data were collected from subjects living in economically disadvantaged rural midwestern counties. Subjects. Subjects were 202 randomly selected parents with préadolescents who indicated interest in family-focused prevention programs. Measures. Conjoint analysis software was employed in computer-assisted telephone interviews to evaluate relative preferences for 39 individual features of family-focused prevention programs falling under 11 categories (e.g., program meeting time, facilitator background). The software also guided computer simulations of parent choices among four types of programs. Results. Findings indicated that meeting time was the most important category of program features. Strongly preferred individual features included meetings scheduled on weekday evenings, instruction by child development specialists, and programs based on extensive research. Two multiple-session programs evaluated via computer simulations incorporated several preferred features and received higher ratings than did single-session programs. Estimated variance z-tests indicated limited differences in perceived importance of program feature categories across sociodemographic subgroups. Conclusions. Findings highlight a) differences in the relative value parents place on various features of prevention programs in the surveyed population and b) the importance of practical aspects of program delivery.

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