Emergency departments (ED) in the USA treat 136.9 million cases annually and account for nearly half of all medical care delivered. Due to high demand and limited resource (such as doctors and beds) availability, the median waiting time for ED patients is around 90 minutes. This research is motivated by a real-life case study of an ED located in central Missouri, USA, which faces the problem of congestion

This paper deals with a model builder for Hybrid Dynamic Systems (HDS), where technological components including sensors in an iconic format can be automatically dragged from a database and interconnected to produce the overall HDS, following industrial technological schemes. Once the model has been created, its consistency can be checked, and a block diagram simulation can be performed. The theory

A coupled analysis of agent behavior and Computational Fluid Dynamics (CFD) model is applied to investigate the fire evacuation effectiveness in a popular metro station in Guangzhou, China. Due to the high density and complexity of traffic, the concept of Required Safe Escape Time and Available Safe Escape Time (RSET/ASET), which is more flexible and adaptable than the “6 minutes” principle, is applied

Because computers (except for parallel computers) generate simulation outputs sequentially, we recommend sequential probability ratio tests (SPRTs) for the statistical analysis of these outputs. However, until now simulation analysts have ignored SPRTs. To change this situation, we review SPRTs for the simplest case; namely, the case of choosing between two hypothesized values for the mean simulation

System verification is an ever-lasting system engineering challenge. The increasing complexity in system simulation requires some level of expertise in handling the idioms of logic and discrete mathematics to correctly drive a full verification process. It is recognized that visual modeling can help to fill the knowledge gap between system experts and analysis experts. However, such an approach has

Based on the two-lane, symmetric traffic model (STCA), a modified traffic model, including Vehicle-to-Infrastructure (V2I) communication (STCA V2I model, for short), is presented. The combined full-autonomous and semi-autonomous vehicles are able to exchange information as well as the intentions of the driver with the surrounding vehicles through V2I communication. In the analyzed case, the communication

Despite the growing popularity of 802.11 wireless networks, users often suffer from connectivity problems and performance issues due to unstable radio conditions and dynamic user behavior, among other reasons. Anomaly detection and distinction are in the thick of major challenges that network managers encounter. The difficulty of monitoring broad and complex Wireless Local Area Networks, that often

Down-times from the in-service failure of power plant components, such as turbine blades, portend dire impacts and consequences in the form of huge financial losses. The susceptibility of steam turbine blades to failure is now being reduced by a novel technique, laser shock peening (LSP), which induces compressive layers through the surface of the blades. Current simulation studies of LSP employing

Brain tumors are a group of cancers that originate from different cells of the central nervous system or cancers of other tissues in the brain. Excessive cell growth in the brain is called a tumor. Tumor cells need food and blood to survive. Growth and proliferation of tumor cells in the cranial space, cause strain inside the brain and thus disrupt vital human structures. Therefore, diagnosis in the

Modeling, verifying, and validating are essential steps in order to build systems and software that do what designers expect. If formal verification, and especially model-checking, is a popular method for proving the correctness of properties, its efficiency depends on the accuracy of the used models and the quality of abstractions. As a consequence, applying verification techniques on large-scale

Obesity is a significant factor in health information and increases the risk of health problems. Hence, an application that can help users to monitor their body mass index (BMI) timelines is needed. The simulation of a personalized 3D body shape may encourage women to control their BMI for a healthy body and pleasant appearance. Therefore, this paper aims to develop computerized 3D models of female

Since high performance is essential to the functioning of emergency departments (EDs), they must constantly pursue sensible and empirically testable improvements. In light of recent advances in computer science, an increasing number of simulation-based approaches for studying and implementing ED performance optimizations have become available in the literature. This paper aims to offer a survey of

Slope stability analysis is a multi-scale problem. Typically, owing to the distinctions of slope scales (e.g., slope height or slope angle) in practical engineering, the stability calculation results of slopes with various scales from numerical methods inevitably exhibit different computational precision levels in the case of identical computational grids, and therefore the stability results of different

The paper, drawing on the example of simulation codes used in nuclear physics and high-energy physics, seeks to highlight the ethical implications of discontinuing support for simulation codes and the loss of knowledge embodied in them. Predicated on the concept of trading zones and actor network models, the paper addresses the problem of extinction of simulation codes and attempts to understand their

In this paper, we present the combined usage of two different simulation levels to evaluate the economic and quality-of-service impact of deploying a fleet of autonomous wheelchairs in a hospital. The first simulation level deals with the physical world and takes into account the characteristics of a real robot, such as dimensions, sensor configuration, and speed. We simulate different trajectories

Missing data is almost inevitable for various reasons in many applications. For hierarchical latent variable models, there usually exist two kinds of missing data problems. One is manifest variables with incomplete observations, the other is latent variables which cannot be observed directly. Missing data in manifest variables can be handled by different methods. For latent variables, there exist several

This paper addresses the development and implementation of an obstacle avoidance strategy for a multi-robot system operating in an unknown environment. This novel strategy is based on the conventional Bug-1 obstacle avoidance algorithm, which is a non-heuristic method for obstacle avoidance in an unknown environment. In the Bug-1 algorithm, a robot circumnavigates the obstacle to find the coordinates

The anisotropy of single crystal copper and crystal orientation have a significant effect on the micro-milling process. At present, there is no systematic and perfect theory to explain the influence of single crystal orientation on the micro-milling process. Therefore, it is urgent to conduct an in-depth study on the micro-milling process of single crystal copper. In this paper, based on the theory

Computer simulations are currently used in diverse scientific disciplines as well as in science teaching. The simulations proposed for physics teaching are designed for specific purposes and allow studying natural phenomena through exploration and/or modeling. In this work, we present an analysis that, based on the theoretical frame provided by the nature of science (NOS), considers some aspects of

The field of public health increasingly utilizes computational models. In this context, computer scientists are confronted with moral dilemmas like those around modeling the distribution of scarce resources. However, there is a lack of research on the ethical implications of computer modeling and simulation (M&S). In this paper I aim to show that taking a transdisciplinary ethical perspective is useful

In this research, the aim is to find the most appropriate inventory management logic and set of rules along with the optimal decision values that will minimize the bullwhip effect in a supply chain, taking the beer game supply chain as a reference model. In order to achieve this, a simulation model of the beer game supply chain is developed along with an ordering strategy based on the Economic Order

This study introduces a state-of-the-art road debris removal system (i.e., automated road debris removal system (ROBOS)) and analyzes its impact on traffic flow using the microscopic simulation model, VISSIM. Robust simulation scenarios were established, and the major parameters of individual scenarios were also included based on extensive interviews with road workers. The performances of road workers

A novel computational technique is applied to investigate particle trapping in straight and bent channel flow paths with various groove configurations in high-speed compressible, particle laden flow. The technique is valid for particle sizes of the same order of magnitude as the groove dimensions and where the particle–flow path, particle–particle, and particle–flow interactions play significant roles

Inspired by the superior fixed and traction characteristics of ostrich foot toenails, we devised, optimized and manufactured the single structure and group arrangement of a new-style bionic spike for sprint shoes to improve athletic performance. The tractive performance of the bionic spike was tested by finite element analysis and experimental verification. The optimized single structure of the bionic

Analyzing demand behavior of end consumers is pivotal in long term energy planning. Various models exist for simulating household load profiles to cater different purposes. A macroscopic viewpoint necessitates modeling of a large-scale population at an aggregate level, whereas a microscopic perspective requires measuring loads at a granular level, pertinent to the individual devices of a household

The United Nations Office for the Coordination of Humanitarian Affairs has asserted that risks in deployment of unmanned aerial vehicles (UAVs) within disaster response must be reduced by careful development of best-practice standards before implementing such systems. With recent humanitarian field tests of cargo UAVs as indication that implementation may soon become reality, a priori assessment of

In this paper, we argue that computer simulations can provide valuable insights into the performance of voting methods on different collective decision problems. This could improve institutional design, even when there is no general theoretical result to support the optimality of a voting method. To support our claim, we first describe a decision problem that has not received much theoretical attention

In recent years, commodity prices have swiftly decreased, narrowing the profit margin for many mining operations and forcing them to find effective cost management strategies to respond to low prices. Given that equipment is one of the most significant assets of a mining company, efficient equipment utilization has strong potential to reduce costs. This paper focuses on the relationship between the

Numerous studies have confirmed the negative impact of the lack of coordination on supply chain performance. In particular, the lack of coordination leads to the bullwhip effect, which has severe impacts on supply chain stability. This paper evaluates a proposed coordination mechanism that allows a decentralized information sharing in multi-echelon supply chains. The proposed mechanism “Info-Smooth”

The growing complexity of embedded and cyber-physical systems makes the design of all system components from scratch increasingly impractical. Consequently, already from early stages of a design flow, designers rely on prior experience, which comes in the form of legacy code or third-party intellectual property (IP) blocks. Current approaches partly address the co-simulation problem for specific scenarios

Waterflooding is considered as one of the most common methods for improving the ultimate recovery of oil reservoirs. The efficiency of a waterflooding operation strongly depends on the determination and quantification of the relative connections between the injection and production wells. Injection and production rates are the most accessible data and they can provide useful information about the interwell

The optimization of man–machine systems is a critical component in the research and development of products but it has been a struggle to improve the optimization accuracy. This study presents an ergonomic optimization method driven by a posture load regulatory network (PLRN). Considering that the differences in work-related musculoskeletal disorders are caused by different occupations, human body

Urban development usually deteriorates the transportation system. For sustainable urban development, policymakers often face the challenging problem of how to optimally allocate overall land use quotas across a number of residential locations according to the performance of the transportation system. This is a kind of Stackelberg competition, where policymakers make land use decisions and travelers

This paper presents the application of information gap decision theory (IGDT) to deal with uncertainties associated with load forecasting in dynamic, environment constrained, coordinated generation and transmission expansion planning. Traditionally, the gaseous emissions are constrained over the whole system. Conventional methods cannot guarantee a practical expansion plan since huge emissions can

Regardless of its origin, in the near future the challenge will not be how to generate data, but rather how to manage big and highly distributed data to make it more easily handled and more accessible by users on their personal devices. VELaSSCo (Visualization for Extremely Large-Scale Scientific Computing) is a platform developed to provide new visual analysis methods for large-scale simulations serving

The efficient utilization and management of a scarce resource such as the intensive care unit (ICU) is critical to the smooth functioning of a hospital. This study investigates the impact of a set of operational policies on ICU behavior and performance. Specifically, the implemented policies are (a) wait time thresholds on how long patients can wait for an ICU bed, (b) the time windows during which

This study examines the feasibility and potential benefits of using simulation to aid designers of large industrial processes. A demon stration of simulations is provided in the basic oxygen furnace shop and subsequent steel-making operations prior to rolling slabs. We explore three design situations: (1) a new processing technology, (2) the removal of bottlenecks in current operations, and (3) sensitivities

A new dynamic modeling methodology, SLIN, allows for the analysis of systems defined by linguistic variables. SLIN applies a set of logical rules which include base, tactical, strategic and structural change. To make the transition from qualitative to quantitative modes, logical rules are also used. SLIN is advanta geously implemented in a very high-level language such as PRO LOG. A simple ecological

A method whereby a parameter optimization program, written in FORTRAN, can be used in conjunction with ACSL (Advanced Continuous Simulation Language) models of dynamic systems is described. The optimization of a projectile's trajectory is used as an example.

Hierarchical, modular specification of discrete-event models of fers a basis for reusable model bases and hence for enhanced simulation of truly varied design alternatives. We describe an envi ronment which realizes the DEVS formalism developed in Zeigler (1984) for hierarchical, modular models. It is implemented in PC-Scheme, a powerful Lisp dialect for microcomputers contain ing an object-oriented

The study of the impact phenomenon on rubber-like materials has been traditionally related to lumped parameter modeling or discrete Finite Element models that require experimentation associated with the material behavior at a level of constitutive modeling, and additional testing to validate their operation in case of engineering applications. This article presents an Artificial Neural Network approach

To study the effects of spatial variability on groundwater flow simulation, some stochastic methods are proposed in this study. The Karhunen–Loeve expansion is utilized to generate the random field of the parameter conductivity. The conventional and pseudo-random, Latin hypercube, and quasi-random sampling methods are employed to generate random vectors in the Karhunen–Loeve expansion. Various Monte

The traditional clock-driven algorithm is very time-consuming when performed on large-scale neuronal networks due to the huge number of synaptic currents computation and low performance of the parallel implementation of the algorithm. We find in this paper that the conductance coefficients of all the synapses coming from the same presynaptic neuron (neuron i for example) does not need to be computed

This paper focuses on controlling traction for a four-wheel electric vehicle by using the longitudinal slip ratio control technique. By keeping the slip ratio value inside an optimal limit, it can be ensured that the maximum driving force is obtainable by increasing the friction force between tire and road. The usefulness of the sliding mode control method is to provide robust performance from the

Urban livability is an important factor in decisions regarding modern urban construction. Based on multi-agent modeling theory, a model of the changes in urban safety livability is proposed to analyze the present situation and the trends in urban safety livability in complex urban systems. Considering safety as an example, five environmental indicators, namely public security, fire protection, traffic

The growing size and complexity of molecular network models makes them increasingly difficult to construct and understand. Modifying a model that consists of tens of reactions is no easy task. Attempting the same on a model containing hundreds of reactions can seem nearly impossible. We present the JigCell Model Connector, a software tool that supports large-scale molecular network modeling. Our approach

The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the minimum energy consumption possible, and in doing so generally refers to Building Automation and Control

We describe a general framework for modeling and stochastic simulation of epidemics in realistic dynamic social networks, which incorporates heterogeneity in the types of individuals, types of interconnecting risk-bearing relationships, and types of pathogens transmitted across them. Dynamism is supported through arrival and departure processes, continuous restructuring of risk relationships, and changes

Several fields have created ontologies for their subdomains. For example, the biological sciences have developed extensive ontologies such as the Gene Ontology, which is considered a great success. Ontologies could provide similar advantages to the Modeling and Simulation community. They provide a way to establish common vocabularies and capture knowledge about a particular domain with community-wide

We extend our basic discrete-event model of Plasmodium falciparum malaria to encompass circumstances in which multiple phenotypic variants of the parasite circulate within interacting human and mosquito populations, and we compare a version in which variants behave independently to one in which they interact through shared host immune responses. Relative to the standard hypothesis of statistical independence

We develop discrete-event simulation models using a single "timeline" variable to represent the Plasmodium falciparum lifecycle in individual hosts and vectors within interacting host and vector populations. Where they are comparable our conclusions regarding the relative importance of vector mortality and the durations of host immunity and parasite development are congruent with those of classic

The fitting of mathematical models to physiological systems can be tedious and difficult, whether one uses analog or digital computer methods. Both methods have their pros and cons depending on the available hardware and software and on the type of modeling. In recent years many digital simulation languages have been written combining analog-like and digital features to facilitate modeling, but, for