Modeling and Simulation Research Papers (original) (raw)

One of the principal themes the NATO Science and Technology Organization (STO) is fostering in 2017 is "Military Decision Making using the tools of Big Data and Artificial Intelligence (AI)". Simulation might play a significant role to play in these developments as it can act as a testbed for such concepts and support the military decision makers in future operations that are enhanced by AI. Simulation is already making a significant impact in the development of AI outside of the defence sector. Companies such as DeepMind and Nvidia are using computer games and simulations to " train " AI and autonomous systems, analogous to humans training in simulations. The rate of progress is high, driven by increases in computing power, availability of data and improved algorithms. AI can now " beat " humans at many computer and board games and is moving towards tackling more strategic games that have parallels with military C2. If such developments translate into the defence sphere then we could foresee humans and autonomous systems training in the same simulation systems, both separately and together, and the AI in the autonomous system being the same as that in the simulation. As autonomous systems proliferate across the nations, M&S technology and techniques might be used to improve the interoperability of autonomous systems. To maximise such synergies, it will be essential that NATO embraces all communities that have an interest in AI. Assessing the risks of potential adversary's use of AI and commercial autonomous systems is also necessary. Despite recent advances, AI development still faces significant technological and ethical challenges and these must be monitored and addressed as necessary.

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- Artificial Intelligence, Modeling and Simulation, Teacher Training, Military

Metalworking companies represent one of the strategic sectors in the regional economy of the Caldas department in Colombia;
in fact, this sector is involved in 31% of the department’s industrial establishments and 29% of industrial employment according to DANE (Colombian State Statistical Department) statistical data from 2005. The sector also exports to Andean countries. However, preliminary studies conducted with 57% of the entrepreneurs from this sector (excluding micro companies and family businesses) have revealed serious structural (technology, processing, installations) and infrastructure weaknesses (production planning, quality systems) in these organisations’ production systems. It is hoped that this paper will lead to disseminating the results amongst the academic community of implementing a comprehensive methodology for improving the production system of a pilot company from this particular sector. An experimental framework for improving the levels reached by the system regarding such priorities is proposed following universally accepted methodology in discrete simulation studies; it proposes using sequential bifurcation, factorial design and response surface experimentation based on defining and weighting the competing priorities which the company should achieve. The improvements in the pilot company’s production system priorities are presented in terms of an effectiveness index (EI) which rose from 1.84 to 2.46 by the end of the study.

Large-scale photovoltaic (PV) integration to the network necessitates accurate modeling of PV system dynamics under solar irradiance changes and disturbances in the power system. Most of the available PV dynamic models in the literature are scope-specific, neglecting some control functions and employing simplifications. In this paper, a complete dynamic model for two-stage PV systems is presented, given in entirely state-space form and explicit equations that takes into account all power circuit dynamics and modern control functions. This is a holistic approach that considers a full range of ancillary services required by modern grid codes, supports both balanced and unbalanced grid operation, and accounts for the discontinuous conduction mode of the dc/dc converter of the system. The proposed dynamic model is evaluated and compared to other approaches based on the literature, against scenarios of irradiance variation, voltage sags, and frequency distortion. Simulation results in MATLAB/Simulink indicate high accuracy at low computational cost and complexity.

- by Efstratios Batzelis and +1
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- Modeling and Simulation, Photovoltaic (PV) Systems

This paper analyses the energy and economic performance of roof and/or façades Building Integrated flat-plate PhotoVoltaic and Thermal (BIPVT) collectors for residential applications. Aim of the analysis is to assess the active and passive effects due to the building integration of solar technologies on the building energy consumptions. In particular, a comparison among innovative building-plant system configurations, based on BIPVT collectors for the simultaneous production of electricity, thermal energy, and domestic hot water, is carried out. The simulation models of the proposed system layouts are designed and implemented in TRNSYS simulation environment for the dynamic assessment of their energy and economic performance. By means of the developed simulation model, the occurring summer and winter building passive energy effects due to the PVT building integration are also analysed.
Several case studies are developed by modelling a representative multi-storey residential building and by taking into account different European climates. For such case studies a suitable energy parametric analysis is performed by varying the thermal resistances and capacitances of the building envelope. By the simulation results interesting design and economic feasibility guidelines are obtained. In particular, by varying the weather location and the building-plant configuration, the adoption of BIPVT panels produces a decrease of the primary energy demands from 67 to 89%. The passive effects of the BIPVT system in both the winter and summer season are also assessed for all the investigated climate zones. The calculated economic profitability resulted slightly better for roof BIPVT panels than for roof and façade applications. For the investigated case studies, the pay back periods appear quite long, varying from 11 years for South European weather zones to 20 for North European ones.

- by Adolfo Palombo and +2
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- Renewable Energy, Sustainable Building Design, Energy Efficiency Buildings, Building Energy Simulation

The proliferation of data together with the increase of computing power in the last decade has triggered a new interest in artificial intelligence methods. Machine learning and in particular deep learning techniques, inspired by the topological structure of neurons network in brains, are omnipresent in the IT discourse, and generated new enthusiasms and fears in our society. These methods have already shown great effectiveness in fields far from architecture and have long been exploited in software that we use every day. Many computing libraries are available for anyone with some programming skills and allow them to "train" a neural network based on several types of data. The world of architecture has not remained external to this phenomenon: many researchers are working on the applications of artificial intelligence to architectural design, a few design software allow exploiting machine learning algorithms, and some large architectural firms have begun to experiment with deep learning methods to put into practice data accumulated over years of profession, with a special interest in environmental sustainability and building performance. If on the one hand, these techniques promise great results, on the other we are still in an exploratory phase. It is then necessary, in our opinion, to understand what the roles of this technology could be within the architectural design process, and with which scopes they can facilitate such a complex profession as that of the architect. On this subject we made ten interviews with as many designers and researchers in the AEC industry, In the article we will report a summary of their testimonies, comparing and commenting on the responses of the designers, with the aim of understanding the potentials of using artificial intelligence methods within the design process, report their perceptions on how artificial intelligence techniques can affect the architect's approach to the project, concluding with some reflections on the critical issues identified during the interviews with the designers.

- by Giuseppe Gallo and +1
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- Artificial Intelligence, Architecture, Machine Learning, Design Process (Architecture)

The paper examines the different types of the architectural models and the purposes assigned to this project tool in Rome and Paris in Seventeenth century. Architectural models allow clients to appreciate the overall effect of a work, and are often preceded by "private" models that artists, such as Bernini, elaborate for themselves.The models are also a regulatory tool for forecasting construction costs and times, binding for master builders and workers. There is a close link between the diffusion of architectural models and the rationalization of the construction site, where "large" models are often proposed, “graffiti” or drawn on a wall, in order to illustrate the projects to workers who are unable to interpret drawings on a smaller scale . In Rome, the capital of a temporal state, and symbol of the Pope's universal spiritual power, the use of models goes hand in hand with a new idea of an art and an architecture based on a skilful manipulation of mechanisms perceptual and optical effects, while in Louis XIV's Paris the models accompany the conception of a new architecture suitable for a "modern" capital city.

Ce modèle présente un aspect très concret des mathématiques que sont les Equations aux Dérivées Partielles, donc on s'intéresse dans ce article a analyser ce modèle a travers la résolution analytique qui fait intervenir les caractéristiques dans un diagramme fondamental en débit et la résolution numérique par discrétisation temporelle après montrer la la méthode utiliser de ce modèle ou la méthodologie de ce modèle et qui utilise l'équation de type hyperbolique de la conservation

- by Chebaane Mohamed and +1
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- Road Transport, Modeling and Simulation, Mathematical Modelling, Traffic

El crecimiento de las ciudades es uno de los principales problemas con gran impacto sobre el territorio, cambiando el uso y cobertura del suelo, y dando lugar a nuevas afectaciones ambientales y sociales. La ciudad de Macas (Ecuador), ha tenido un crecimiento poco regulado y disperso, por lo que predecir su expansión coadyuvaría a preveer posibles inconvenientes a futuro. El objetivo del estudio fue, generar un modelo de crecimiento tendencial urbano de Macas al año 2030, mediante modelación espacial multivariable, para que sirva como una herramienta en la delimitación del suelo rural de expansión urbana según la LOOTUGS del Ecuador. Se aplicaron diversas técnicas de simulación espacial, de las cuales tres fueron las escogidas para su comparación y selección del mejor modelo, como fueron: autómatas celulares con perceptrón multicapa (AC – MLP) y con algoritmos genéticos (AC – AG), y aprendizaje ponderado por similitud (SimWeight). Los resultados de la validación mostraron un 31%, 47% y 54% de similitud para AC – AG, AC – MLP y SimWeight, respectivamente, por tanto, éste último fue el mejor modelo. Con la mancha urbana resultante, se identificó una tendencia de expansión hacia el Norte, y delimitó una propuesta del suelo de expansión urbana para Macas, la misma que está adyacente al área urbana actual. El modelo de ciudad deseado, las políticas que se tomen y la inclusión de este tipo de análisis espacial, permitirán planificar de una forma sostenible y ordenada a la ciudad.

The university canteen is a queuing system with time dependent arrival patterns and limited resources. It has created the problem of students waiting in the queue during the lunch hour. This study purposively selected a Sri Lankan state university canteen composed of two counters and corresponding queues. The data were collected during the lunch hour of five consecutive week days. The sample included 200 students. The queuing system was modeled using the student version of Rockwell ARENA 14.5. The inter arrival times were calculated and inserted to the input analyzer to find the corresponding arrival patterns of students to the university canteen queues. It showed non uniform arrival rates explained by different patterns. The modeled system was run for one hour to find average values for waiting time of the students separately in two queues, number waiting in queues and number of arrivals and service receipts. The simulation showed that 64 students received the service among 64 successive arrivals. The results explained the average waiting times in queue 1 and queue 2 to be 2.35 and 3.03 in minutes respectively. The number waiting at counter 1 and 2 were 1.26 and 1.62 customers. The study further revealed the possibility of reducing waiting times at counter 1 and counter 2 to 0.68 and 0.89 minutes respectively by doubling the resources at both counters. The findings suggested improving the customer service of the system by opening an additional counter during the lunch hour and redesigning the layout considering the financial feasibility.

A lot of design cases involve editing a preliminary design or design template to suit the requirement. This paper focuses on the methods that can be used to automate editing of designs in CREO by means of the CREO VB API. The advantage of this API is that it can even be used from MS excel, although in this article I will be focusing on VB.NET. The idea is to change one or more of the following Parameters, Dimensions and Relations automatically through code which will change the design. Usually this involves changing one factor manually and VB code will change the others accordingly. The rest of the article focuses on how this can be achieved.

- by Pratheesh Russell
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- Modeling and Simulation, PTC Creo

The increasing wind power generation requires the updating of the computational tools that support decision making in the operation and planning of electric power systems. This work describes a methodology to model the spatial correlations among wind speeds probability distributions in probabilistic power flow. The proposed methodology is based on Nataf transformation and Monte Carlo Simulation. The proposed methodology is illustrated in case studies with the IEEE 24 bus test system, highlighting the importance of adequately considering such correlations.

The design of an aircraft is a prolonged process that consists mainly of three design phases which are: the conceptual design, the preliminary design, and the detailed design. A set of design goals or requirements along with a flight mission profile must be available to provide a baseline for the conceptual design process.
The design process starts with the aircraft's intended purpose. Commercial airliners are designed for carrying a passenger or cargo payload, long range and greater fuel efficiency.
By drawing a set of configurations, designers seek to reach the design configuration that satisfactorily meets all requirements as well as go hand in hand with factors such as aerodynamics, propulsion, flight performance, structural and control systems.
The final product is a conceptual layout of the aircraft configuration on paper or computer screen, to be reviewed by engineers and other designers.

- by Sultan M. Mukut
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- General Aviation, Modeling and Simulation, Aircraft Design, Conceptual Design

O Serviço Municipal de Saúde do Rio de Janeiro tem exigido um projeto para avaliar a capacidade de atendimento do serviço de emergência, tendo em vista os desastres urbanos e naturais que estão acontecendo em muitos lugares, além dos dois grandes eventos que estão prestes a acontecer na cidade do Rio de Janeiro em 2014 e 2016. O objetivo deste trabalho é propor um Sistema de Informações e Coordenação que envolva três órgãos públicos: o Centro de Operações do GSE/SAMU, o Centro de Operações da Prefeitura do Rio de Janeiro e o Núcleo Interno de Regulação (NIR) dos hospitais municipais. O modelo baseia-se no fluxo de informações, centrando-se nos pacientes de alta complexidade. A simulação de eventos discretos é utilizada para identificar como o sistema responde à demanda aumentada. Afirma-se que o “uso da informação” é a chave para melhorar o desempenho global do sistema.

- by MARCOS SANTOS
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- Monte Carlo Simulation, Modeling and Simulation

Özet: Kavramsal ve üç boyutlu tasarımı yapılan orta ölçekli insan kara aracının süspansiyon sistemi modellemesi, pasif olarak çeyrek taşıt modeli ile matematiksel olarak modellenmiş ve modelleme Matlab/Simulink ortamında oluşturulmuştur. Askeri kara aracının öngörülen süspansiyon sistemi parametreleri kullanılmış ve APG tümsek testi referans alınarak süspansiyon sistemini test etmek amacıyla bir parkur tasarlanmıştır. Süspansiyon sistemi modeli çözdürülerek sonuçlar tartışılmıştır.

The 21st century has witnessed precipitous changes spanning from the way of life to the technologies that emerged. We have entered anascent paradigmshift(industry 4.0) where sciencefictions have becomescience facts, and technologyfusion is the main driver.us, ensuring that any advancement intechnologyreach andbenefitall istheideal opportunity foreveryone.In thisstudy, disruptive technologies of industry 4.0 were explored and quantified in terms of the number of their appearances in published literature.e study aimed at identifying industry 4.0 key technologies which have been ill-defined by previous researchers and to enumerate the required skills of industry 4.0. Comprehensive literature survey covering the field of engineering, production, and management was done in multidisciplinary databases: Google Scholar, Science Direct, Scopus, Sage, Taylor & Francis, and Emerald Insight. From the electronic survey, 35 disruptive technologies were quantified and 13 key technologies: Internet ofings, Big Data, 3D printing, Cloud computing, Autonomous robots, Virtual and Augmented reality, Cyber-physical system, Artificial intelligence, Smart sensors, Simulation, Nanotechnology, Drones, and Biotechnology were identified. Both technical and personal skills to be imparted into the human workforce for industry 4.0 were reported. e review identified the need to investigate the capability and the readiness of developing countries in adapting industry 4.0 in terms of the changes in the education systems and industrial manufacturing settings. is study proposes the need to address the integration of industry 4.0 concepts into the current education system.

- by Orhan TÜRK
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- Modeling and Simulation, Electric Vehicles, Automotive Engineering, Dynamic Modeling

Detailed characterisation and 3D-modelling of the shallow subsurface was carried out for the construction of a Radial Collector Well (RCW) at the drinking water pumping station of Brabant Water at Macharen (near 's Hertogenbosch, province of Noord-Brabant, southern Netherlands). The objective was to assess the lithological and hydraulic properties of the uppermost 30 m of the subsoil in order to find the optimal depth and orientation of the 4 horizontal collector arms of the RCW.

- by Hans Veldkamp and +2
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- Geology, Hydrogeology, Geotechnical Engineering, Groundwater

In this paper we report the extent to which dielectric relaxation in typical monolithic capacitors degrades the performance of chargemedistrihution analog-to-digital (A/D) converters, We show experimental device data from a monolithic capacitor test circuit, describe an empirical capacitor model fit to the rneasnrements, and compare simulated A/D system errors with those observed in a monolithic, 10-b, 3.3m&s A/D converter. The excellent agreement found in this comparison demonstrates that the transient error in A/D-converter code transition voltages due to dielectric relaxation may be accurately predicted. The modeling and simulation techniques discussed are important tools both for the selection of proper capacitor technology and iu the development of circuit designs insensitive to dielectric relaxation. This analysis is also applicable to any circnit where precision is derived from capacitor characteristics, such as sample-and-hold circuits aud switchedcapacitor filters.

- by Greg Warwar
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- Materials Science, Modeling and Simulation, IEEE, Dielectric Relaxation

In 1950 Markowitz first formalized the portfolio optimization problem in terms of mean return and variance. Since then, the mean-variance model has played a crucial role in single-period portfolio optimization theory and practice. In this paper we study the optimal portfolio selection problem in a multi-period framework, by considering fixed and proportional transaction costs and evaluating how much they affect a re-investment strategy. Specifically, we modify the single-period portfolio optimization model, based on the Conditional Value at Risk (CVaR) as measure of risk, to introduce portfolio rebalancing. The aim is to provide investors and financial institutions with an effective tool to better exploit new information made available by the market. We then suggest a procedure to use the proposed optimization model in a multi-period framework. Extensive computational results based on different historical data sets from German Stock Exchange Market (XETRA) are presented.

- by R. Mansini
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- Computational Economics, Econometrics, Modeling and Simulation, Risk Management

The main contribution of this paper is to present the state-space model of an omnidirectional drivetrain (Kiwi drive) for mobile robots. Holonomy or omnidirectional movement of mobile robots is important in applications where navigation through tight space is required. Besides the already available literature regarding either dynamic or kinematic models, this paper presents the complex analysis of a mechatronic system and shows a coherent model that takes into account both the kinematics and the dynamics of a coupled electromechanical system. The model was developed based on two holonomic mobile robots: the Festo Robotino® and the MOGI Ethon. A simulation software developed by the authors is also presented for numerical evaluation of the model. The simulation results qualitatively confirm the model by fulfilling the empirical requirements. Both the model and the simulation software are expandable in order to improve the accuracy of the model describing actual mobile robots. Compared...

A practical universal modeling and simulation approach is presented in this paper to show that accurate battery pack simulation can be achieved if cell-to-cell variations were taken into account. A generic equivalent circuit model was used in the approach with parameters deduced from cell testing with proper protocols, which could come from live cell monitoring in a control circuitry. Using a single cell model, which was validated against experimental data and demonstrated with validity of high accuracy in predicting cell performance, we showed that such a high accuracy in single cell model is essential for a high fidelity pack simulation. It is also important to derive statistical confidence intervals accurately from experiments to characterize intrinsic cell-to-cell variations in capacity and internal resistance, which need to be considered in the pack model. If parameters for each individual cell were correctly approximated and used in the pack model, the accuracy in the prediction of pack performance could be significantly improved.

- by Bor Yann Liaw
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- Engineering, Modeling, Performance, Modeling and Simulation

With the development of the modeling and computer technology, the scale of mate-
rial has been expanded from macro- to micro-, also from micro- to nanoscale. The
development of molecular modeling tools to describe and predict the mechanical
properties of structural materials reveals to be of undeniable practical importance.
At the nanometer scale, anisotropy is the consequence of differences in the direc-
tional arrangements of atomic structure, the force between atoms, such as van der
Waals force, typical Coulomb force, and other forces.
Till early twenty-first century, the approximate solution of the Schrödinger equa-
tion in quantum mechanics field is almost equivalent to the importance of using
Newton’s laws widely to solve classical mechanics problems. Density functional
theory (DFT) as a first-principles theory and a solid band theory in quantum
mechanics has own a great success in linking physical properties and molecular
structure, the calculation with exact accuracy but for low computational efficiency
for macromolecular structure. Molecular dynamics (MD) has obvious advantages
in simulating macromolecular structure, with very high computational efficiency
but for much dependency of atomic potential parameters. Besides, MD method is
limited into a range of structure at atomic scale level and it cannot effectively solve
continuum mechanics problems like practical engineering application using finite
element method (FEM). So we look for a modeling tool so as to further widen the
application fields of nanoindentation simulation with consideration of atomic
forces at nanoscale level. In addition to the tradition of DFT and MD methods
that we briefly introduced above, a so-called AFEM modeling methodology at the
atomic scale (or nanoscale) is further investigated since the macroscopic properties
depend largely on the physicochemical properties of the interatomic bonds.
Nanoscale modeling and mechanical properties by using the density functional
theory (DFT), a so-called atomic finite element method (AFEM), and the classi-
cal molecular dynamics (MD) method are especially concerned according to the
modeling requirement of different crystals structures investigated.
This is a book of a professional and systematic scientific research by Dr. Jia Fu.
This book is committed to model and to calculate mechanical properties (Young’s
modulus especially) of typical anisotropic crystals structures (cubic crystals: CaO
and MgO; hexagonal crystals: CH and calcite; monoclinic crystals: 11 Å tobermorite
and gypsum; others: CNT and graphene; monolithic structures of C▬S▬H (I)
(Ca/Si = 0.67) and C▬S▬H (II) (Ca/Si = 1.67)) by programming with using three
methods above. Omitting the description of these structures’ importance, elastic
moduli are separately calculated by either homogenization or curve fitting of the
linear portion of the stress-strain curve by the corresponding numerical simula-
tions. At the end, nanoindentation experiments, SEM, and nanoindentation simula-
tions are carried out to determine elastic moduli of several phases in cement pastes.
As crystal structures at nanoscale always tend to exhibit anisotropy, our research
objects of typical cement phase structures depending on crystal types and practical
research needs in book are mainly divided into five types: cubic crystals (CaO
and MgO), hexagonal crystals (calcite and portlandite), monoclinic crystals (11 Å
tobermorite and gypsum), monolithic structures: C▬S▬H (I) (Ca/Si = 0.67) and
C▬S▬H (II) (Ca/Si = 1.67), and other crystals structures (CNT, graphene). These
structures are typical constituents of the microscale Portland hydrated cement
paste (HPCP) and their Young’s moduli are needed in a 3D multiscale mortar model.
Nanoscale modeling helps build the bottom-up multiscale model, by which the
accurately independent models of typical structures can be verified by the elastic
moduli obtained at atomic scale, then the needed multiscale model can be estab-
lished. In this book, we mainly focus on modeling and calculating the mechanical
properties of these typical anisotropic crystal structures at nanoscale with a high
efficiency, then determining homogenized elastic moduli of these structures with a
larger scale.
In summary, by identifying relevant parameters using the improved AFEM method
and other computational program, it therefore connects nanoscale modeling and
continuous pattern of deformation behavior from small scales to larger scales.
We believe that our research above will be expanded the existing research and to
provide further detailed parameters of our research objects, thus leads to a certain
practical significance.

The Region of Yogyakarta (DIY) is one of the regions in Indonesia. Community growth in Yogyakarta reaches 1.34% in 2017 which can cause various problems such as unemployment community that continues to grow every year. In addition, another serious problem in Yogyakarta is high congestion which is implicated by the increasing number of population in DIY. Those problems have a bad influence on regional cash which is very useful in the development of the area. This study aims to increase regional cash of DIY by considering available employment and traffic congestion. Because the problem is so complex, a system dynamics approach is used to solve it. Based on the simulation results using Powersim 2005, the main cause of unstable regional cash is the high cost of building new roads, the cause of high cost of building new roads is congestion, and the cause of congestion is the high demand for vehicles by residents of the Yogyakarta area. Therefore, it is necessary to reduce the level of demand for vehicles to increase the cash of the DIY area. By reducing the demand for vehicles to 0.00003, which initially 0.00005 has succeeded in making the regional cash stable and increasing continuously. In addition, to increase employment in order to eliminate the population unemployment in Yogyakarta, it can be done by increasing the growth rate of new companies. By increasing the growth rate of the new company to 1.2 which initially 1 has succeeded in making employment increased continuously.

Practicing best calf management practices in housing, feeding and health are important for growing the future replacement stock. This is important for sustainability of the dairy herd where a significant proportion of the national dairy herds are smallholders with poorer calf performance than is in large commercial herds. Kenya's national dairy herds comprise over 75% smallholders, some affiliated to cooperatives offering regular extension advises on best calf management practices to their members. This study tested the hypothesis that producer attitudes reflect calf management practices that are implemented in large commercial and smallholder herds. The hypothesis was tested with a sample of large commercial dairy herds and smallholder herds affiliated to cooperative societies. Producer attitudes and management practices in calf housing, feeding and health were captured regarding standard management practices on a five point scale of agreement. The responses were analyzed to reveal the underlying differences between the herds using non-parametric chi square test and Mann-Whitney U test statistics. Compared to large commercial dairy producers, smallholders expressed more negative (p<0.05) attitudes towards practicing the recommended housing (calf pen disinfection, spacing in pen, bedding), feeding (colostrum feeding, concentrate supplementation) and towards health (vaccination, deworming and ecto parasite control). The negative smallholders' attitudes were reflected in poorer (p<0.05) implementation of the recommended calf housing practices (pen disinfection), feeding practices (colostrum and milk feeding, concentrate supplementation and weaning procedure) and health practices (vaccination and ecto parasite control). To attain improved calf performance and sustainable dairy herds, smallholder dairy producers need change of attitude towards implementing the recommended calf management practices. In housing, the target areas are pen disinfection, housing calves in individual pens to avoid crowding and improved bedding. In feeding, the target areas are colostrum and milk feeding and concentrate supplementation while in health the target areas are vaccination, deworming and ecto parasite control practices. Introduction Practicing best calf management practices in housing, feeding and health is important for rearing the future replacement stock. This is important for sustainability of the dairy herd where a significant proportion of the national dairy herd attain poorer calf performance. Kenya has such dairy herd in which smallholder's comprise75% of the national herd and with poorer calf performance than in the fewer remainder medium and large commercial herds [3]. Good calf management practices enhance calf survivability and performance and subsequently, quality replacement stock for the future herd [17]. Important calf management is in housing, feeding and health. Calf housing should be well ventilated, partitioned into individual pens which are regularly disinfected, cleaned and the bedding are kept dry to provide calf comfort, good welfare and ease early disease detection of diseases. This way, good housing contributes to improved calf performances [5]. Good calf feeding practices begin with colostrum feeding, essential for passive immunity to calf. Colostrum feeding is followed with milk feeding, which has to be warm, hygienic and in enough quantity corresponding to calf body weight to support sufficient growth. Supplemental concentrate is necessary after weaning to sustain high growth rates [16, 4] .

Today's households face a huge variety of electricity consuming devices on the one hand, and increasing electricity prices and increased awareness for environmental sustainability on the other hand. Fluctuating electricity tariffs currently evaluated by electricity suppliers have the potential to make it even more complex for the electricity consumer to keep costs low. We want to help the consumer to manage this complexity and increase her or his awareness for the electricity consumption of the household's devices. Therefore, we have developed a tool which allows to model and simulate the set of electricity consuming devices, their loads, and electricity tariffs. It is possible to create schedules for the usage of devices, calculate the resulting load curve and automatically optimize the schedule based on fluctuating power tariffs while paying attention to customer definable constraints. Furthermore, the tool allows to compare modeled and metered load curves, which is especi...

- by Mark Eilers
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- Computer Science, Economics, Modeling and Simulation, Environmental Sustainability

En el municipio de Caldas (Colombia), uno de los sectores estratégicos para la economía regional es el de las pymes metalmecánicas; de hecho, este sector, según estadísticas del DANE a 2005, participa aproximadamente con el 31% de los establecimientos industriales del departamento y con un 29% del empleo industrial, además tiene vocación exportadora hacia países andinos. Sin embargo, estudios preliminares realizados al 57% del universo empresarial de este sector (no incluye microempresas ni famiempresas), demuestran serias falencias de tipo estructural (tecnologías, procesos, instalaciones) e infraestructural (programación de la producción, sistemas de calidad, etc.) en los sistemas de producción de estas organizaciones. Mediante este artículo se espera divulgar entre la comunidad académica los resultados obtenidos al aplicar una metodología integral de mejoramiento del sistema de producción en una empresa piloto del sector. A partir de la definición y ponderación de las prioridades competitivas que la empresa debe alcanzar, y siguiendo la metodología universalmente aceptada en estudios de simulación discreta, se propone un marco de experimentación para mejorar los niveles alcanzados por el sistema en dichas prioridades empleando técnicas de bifurcación secuencial, diseño factorial en experimentación y superficies de respuesta. Al final se presentan las mejoras alcanzadas en las prioridades competitivas en términos de un índice de efectividad (IE) del sistema de producción de una empresa piloto estudiada al pasar éste de 1,84 a 2,46. Palabras clave: empresas metalmecánicas, sistemas de producción, simulación discreta, bifurcación secuencial, diseño estadístico de experimentos, superficies de respuesta.

- by Omar gomez
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- Modeling and Simulation, Discrete-Event Simulation, Metalworking, Job shop scheduling

Panelists respond to three questions, " How does your DoD initiative promise to increase readiness for the fighting forces?", "Where will the distributed simulation technology in your program take us by 2005?" and "What changes in available DoD infrastructure would facilitate the use of the system(s) emerging from your program?" The panelists include senior members of the Department of Defense civilian management team working in the Modeling and Simulation field.

- by Philip Barry
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- Packaging, Technology Management, Modeling and Simulation, Team work

The three volumes of this report describe research findings on three closely related fronts: (1) Development of a theory of the cognitive skills that individuals need to make effective decisions in fast-paced and uncertain environments; (2) development and testing of methods for training critical thinking skills on the battlefield; and (3) development of an advanced system architecture to support adaptive instruction and feedback in critical thinking training. Theory development focused on mental models and critical thinking about mental models in a team context, where initiative might be necessary. Training addressed mental models and critical thinking on three major themes: purpose, time, and maneuver. The training was utilized and successfully tested in an advanced tactics course at the Command and General Staff College. Finally, algorithms were developed to simulate both rapid recognitional responding and more reflective reasoning when time is available.

- by Terry Bresnick
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- Critical Thinking, Modeling and Simulation

Scientific evidence on the impact of small-scale living facilities (SSLFs) on quality of life of nursing home clients remains scarce. In this study a simulation model is developed to examine the performance of SSLFs, in terms of meeting the time preferences of their residents. We model scheduled care using historical data and unscheduled care using a Poisson-Gamma mixture model. The model is used to explore the impact of a change in demand characteristics, duration of care delivery, travel time, allocation flexibility, shifts, number of clients and allocation policy. The results show that to further improve the performance, the focus should lie on: (1) increasing the allocation flexibility of care workers and the number of clients per SSLF, and (2) time dependent staffing. Furthermore, this study shows that simulation is a useful tool for assessing and improving daily nursing home operations. The presented simulation model provides a basis for building a decision support tool for nursing home managers.

- by Dennis Moeke
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- Long Term Care, Modeling and Simulation, Health Care Management, Quality of Care

This paper presents the technique of constructing models of behavior algorithms of radio electronic complex system using new scheme of paths method. This technique allows estimation of the efficiency indexes of RECS taking into account... more

- by Leonid Ozirkovskyy
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- Algorithms, Complex Systems, Modeling and Simulation, Mathematical Modelling

The essential oil of Zataria multiflora Boiss., cultivated in Iran, was extracted by subcritical water extraction (SCWE) and compared with two conventional methods, including hydrodistillation and Soxhlet extraction. The extraction efficiencies of different temperatures (100, 125, 150 and 175C), mean particle sizes (0.25, 0.50 and 1 mm) and water flow rates (1, 2 and 4 mL/min) were investigated at 20 bar. The separation and identification of the components were carried out by gas chromatrography (GC)‐flame ionization detection and GC‐mass spectrometry. The best operating conditions for the SCWE of Z. multiflora Boiss. were determined to be at 150C temperature, 0.50‐mm mean particle size and 2 mL/min flow rate for 150 min extraction time. The SCWE method resulted in a more valuable essential oil with respect to the oxygenated components.

Considering the pollution problems and energy crisis today, investigations have been focused on lowering the concentration of toxic components in combustion products and decreasing fuel consumption by using renewable alternative fuels. The effects of ethanol addition to unleaded gasoline on the performance and pollutant emission of the spark ignition engine are established both analytically and experimentally. In the present work a quasi-dimensional model was developed to study the effect of ethanol blending on the thermodynamic cycle of the engine. The Ricardo E6/US engine has been used for verification and comparison of the results of the model with experimental tests. The results of the standard ASTM methods showed that, with increasing ethanol content, the research octane number of the blended fuels increases, while the Reid vapour pressure of the blended fuels initially increases to a maximum at 10 vol % ethanol addition and then decreases. The results of the study showed that the addition of ethanol (from 0 to 30 vol %) increases the engine power, thermal efficiency, and specific fuel consumption and reduces the nitrogen oxides, carbon monoxide, and hydrocarbon emissions. The ethanol added improves the combustion process, reduces the crevices flow energy, reduces the cylinder temperature, reduces the ignition delay, speeds up the flame front propagation, and reduces the combustion duration. The high useful compression ratio, which produced maximum engine power, was directly proportional to the ethanol percentage in the mixture.

How can you make your first project, and every project, successful? Modeling can certainly be fun, but it can also be quite challenging. You want your first and every project to be successful so you can justify continued work. Unfortunately a simulation project is much more than simply building a model-the skills required for success go well beyond knowing a particular simulation tool. A 30 year veteran who has done hundreds of successful projects shares important insights to enable project success. He also shares some cautions and tips to help avoid common traps leading to failure and frustration.

- by David T Sturrock
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- Project Management, Modeling and Simulation, Simulation, Student Success

Advanced manufacturing approaches, including additive manufacturing (i.e., " 3D printing ") of metallic structures requires a change to qualification strategies. One approach, informed qualification, integrates modeling strategies to make predictions of material characteristics, including the prediction of tensile properties for given chemistries and microstructures. In this work, constitutive equations are developed and presented that can predict the yield strength of additively manufactured Ti-6Al-4V subjected to one of three different heat-treatments: a stress relief anneal in the aþb phase field; a hot isostatic press treatment in the aþb phase field; and a b-anneal. The equations are nominally identical, though different strengthening mechanisms are active according to subtle microstructural differences. To achieve an equation that can predict the yield strength of the material, it is also necessary to include an assessment of dramatic reduction in the tensile strength due to texture (i.e., a " knock-down " effect). This has been experimentally measured, and included in this paper. The resulting predictions of yield strength are generally within 5% of their experimentally measured values.

- by Iman Ghamarian
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- Computational Modelling, Titanium, Modeling and Simulation, Additive Manufacturing

Climate is one of the single most important factors affecting watershed ecosystems and water resources. The effect of climate variability and change has been studied extensively in some places; in many places, however, assessments are hampered by limited availability of long-term continuous climate data. Weather generators provide a means of synthesizing long-term climate data that can then be used in natural resource assessments. Given their potential, there is the need to evaluate the performance of the generators; in this study, three commonly used weather generators—CLImate GENerator (CLIGEN), Long Ashton Research Station Weather Generator (LARS-WG), and Weather Generators (WeaGETS) were compared with regard to their ability to capture the essential statistical characteristics of observed data (distribution, occurrence of wet and dry spells, number of snow days, growing season temperatures, and growing degree days). The study was based on observed 1966–2015 weather station data from the Western Lake Erie Basin (WLEB), from which 50 different realizations were generated, each spanning 50 years. Both CLIGEN and LARS-WG performed fairly well with respect to representing the statistical characteristics of observed precipitation and minimum and maximum temperatures, although CLIGEN tended to overestimate values at the extremes. This generator also overestimated dry sequences by 18%–30% and snow-day counts by 12%–19% when considered over the entire WLEB. It (CLIGEN) was, however, well able to simulate parameters specific to crop growth such as growing degree days and had an added advantage over the other generators in that it simulates a larger number of weather variables. LARS-WG overestimated wet sequence counts across the basin by 15%–38%. In addition, the optimal growth period simulated by LARS-WG also exceeded that obtained from observed data by 16%–29% basin-wide. Preliminary results with WeaGETS indicated that additional evaluation is needed to better define its parameters. Results provided insights into the suitability of both CLIGEN and LARS-WG for use with water resource applications.

- by Sushant Mehan
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- Climatology, Data Analysis, Monte Carlo Simulation, Modeling and Simulation

Within the past few decades, diverse modeling and simulation tools have been applied an eztensive applications. The approaches used range from programming with a specific simulation description language to automation using an icon-driven user interface. The advantage in utilizing simulation is to assess the system's performance prior t o an actual implementation. Functionality, maintainability, and expansibility are the primary criteria used to make a choice of a specific tool. To strengthen these criteria, a general-purpose environment called Performance Object-oriented modeling and Simulation Environment (POSE) has been developed. The objectives of POSE are to automatically construct simulation models for the systems to be designed, to eficiently define the system performance measures, and to accurately generate the performance data expected. The environment is briefly summarized and an application study for a multiprocessor computer system is presented. 161 0-8186-6440-lB4 $04.00 0 1994 IEEE

The automated material handling system (AMHS) is a highly automated transport solution of actual 300mm semiconductor waferfabs. The big logistic challenge in such a running system is the just-in-time delivery of lots (carriers). Therefore, beside tracks and vehicles, there are different storages (stocker) and buffers (under track storages and load ports) integrated in such a transport system. To conquer the

In this project, we extend the work already done in [1.] to include a generalised mathematical framework for studying and explaining the dynamics and behavior of crowds of humans. The method is both analytical and numerical. The numerical methods are used to solve the differential equations of crowds that are derived analytically. The analytical and numerical solutions are compared and their relevance is shown. In this project, we study mainly two types of responses of a crowd: Position Response and Density Response. The latter is formulated using stressors using an approach similar to [2.] which also enables us to derive the General Adaptation Syndrome (GAS) Model in a very generalised form. Finally, we extend stressors to define inter-crowd and intra-crowd interactions using a parameterisation linking it directly to a generalisation of the stressdensity equation. The detailed calculations are done in the later part of this paper. (Refer to Page 21 of this doucument).

We present a transient Boltzmann equation based transport and reaction model for atomic layer deposition ͑ALD͒ at the feature scale. The transport model has no adjustable parameters. In this article, we focus on the reaction step and the postreaction purge steps of ALD. The heterogeneous chemistry model consists of reversible adsorption of a reactant on a single site, and irreversible reaction of a second gaseous reactant with the adsorbed reactant. We conduct studies on the effect of the kinetic rate parameter associated with the reaction. We provide results for number densities of gaseous species, fluxes to the surface of the feature, and surface coverage of the adsorbing reactant as functions of time. For reasonable reaction rate parameter values, the time scale for gas transport is much smaller than that for reaction and desorption. For these cases, an analytic expression for the time evolution of the surface coverage of the adsorbing reactant provides a good approximation to the solution obtained from the transport and reaction model. The results show that fractional coverage of the adsorbing reactant reduces significantly in the reaction step due to reaction with the gaseous reactant and desorption. Larger values of the reaction rate parameter lead to larger reductions in the fractional coverage during the reaction step. For smaller values of the reaction rate parameter, the decrease in coverage is dominated by desorption. The surface coverage of the adsorbing reactant also decreases during purge steps, due to desorption.

- by Matthias Gobbert
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- Chemistry, Modeling and Simulation

One of the proposed purposes for software process simulation is the management of software development risks, usually discussed within the category of project planning and management. However, modeling and simulation primarily for the purpose of software development risk management has not been explored and is quite limited. This study describes an approach to simulate Low Morale - a risk factor, to analyze its effect on certain software development risk management activities.

- by rachna soni
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- Computer Science, Software Development, Modeling and Simulation, Risk Management

El siguiente trabajo es una síntesis sobre los resultados de la teoría de S-
sistemas creada en 1960 por Michael A. Savageau, exponiendo ejemplos para
mejorar la comprensión y brindando teoremas de tal modo que se asegure
la formalidad matemática. Dicho trabajo ha sido realizado por el equipo de
Investigación Bone Remodeling que está formado por la Dra. Silvia Jerez, el
Dr. Francisco Solís y el Lic. Enrique Díaz.
Palabras clave: S-sistemas, Simetrias, Modelación, Puntos de equilibrio,
aproximación no lineal

In this project, we extend the work already done in [1.] to include a
generalised mathematical framework for studying and explaining the
dynamics and behavior of crowds of humans. The method is both
analytical and numerical. The numerical methods are used to solve
the differential equations of crowds that are derived analytically. The
analytical and numerical solutions are compared and their relevance
is shown. In this project, we study mainly two types of responses of
a crowd: Position Response and Density Response. The latter is
formulated using stressors using an approach similar to [2.] which
also enables us to derive the General Adaptation Syndrome (GAS)
Model in a very generalised form. Finally, we extend stressors to
define inter-crowd and intra-crowd interactions using a
parameterisation linking it directly to a generalisation of the stressdensity
equation.

- by shreyak chakraborty
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- Mathematics, Computer Science, Modeling and Simulation, Multi-Agent Systems
- by Andrea Chávez Heredia
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- Biomathematics, Modeling and Simulation, Numerical Analysis

Realistic renderings contain a large amount of information about the spatial, geometric and material properties of prospective buildings that can directly affect design decisions, yet these images are most of the time used as after-the-fact representational visualizations. In this paper we propose a model to make the realistic images a very part of the design and decision making process. If we are to utilize realistic images during earlier decision making stages of the design processes, then we should develop experiential workflows in which we can create and interact with immersive realistic images real-time. We take several steps towards establishing an interactive rendering-animating-editing workflow that enables the designers to work with real-time rendered stereoscopic animations. In our system, we use realism to create an immersive exploration environment, as opposed to underutilizing it to represent a static moment.