Integrated Simulation Tool Research Articles

Why, how, and how far should microbiological contamination in a coastal zone be mitigated? An application of the systems approach to the Thau lagoon (France)

This paper describes the building of an integrated simulation tool based on a systems approach, and its contribution to local political discussion of the mitigation of microbiological contamination of the water in a coastal area. Local management schemes view water quality as a high-priority environmental objective. In practice, how far this objective is achieved depends on trade-offs between the costs of improved water treatment facilities and the acceptable impacts of water contamination. An in-the-field experiment in collaboration with local managers was carried out in the Thau lagoon on the French Mediterranean coast during the SPICOSA (Science and Policy Integration for Coastal System Assessment) project, from 2007 through 2011. It consisted of building a modeling platform and an integrated assessment framework for simulating exploratory scenarios. The modeling platform combines a dynamic contamination model, which represents the sources of microbiological contamination, wastewater treatment facilities, and physical mechanisms of lagoon contamination, with a prospective economic model, which estimates the patterns of development of economic activities in the area through a holistic approach. Exploratory scenarios are used to assess the risk of water contamination and the efficiency of management measures, under various assumptions about the evolution of the system. The contamination simulations suggest that the work currently planned by local authorities will be inadequate for preventing increased water pollution, and that additional but fairly inexpensive management measures for maintaining the current level of water quality should be considered. The integrated assessment framework estimates the ecological and socio-economic impacts of the various pollution mitigation policies in the broader context of possible local development patterns. The results illustrate how the systems approach may aid in the design of an applicable water policy based on operational objectives and feasible technical options.

Energy-efficient HVAC systems: Simulation–empirical modelling and gradient optimization

Abstract This paper addresses the energy saving problem of air-cooled central cooling plant systems using the model-based gradient projection optimization method. Theoretical–empirical system models including mechanistic relations between components are developed for operating variables of the system. Experimental data are collected to model an actual air-cooled mini chiller equipped with a ducted fan-coil unit of an office building located in hot and dry climate conditions. Both inputs and outputs are known and measured from field monitoring in one summer month. The development and algorithm resulting from the gradient projection, implemented on a transient simulation software package, are incorporated to solve the minimization problem of energy consumption and predict the system's optimal set-points under transient conditions. The chilled water temperature, supply air temperature and refrigerant mass flow rate are calculated based on the cooling load and ambient dry-bulb temperature profiles by using the proposed approach. The integrated simulation tool is validated by using a wide range of experimentally collected data from the chiller in operation. Simulation results are provided to show possibility of significant energy savings and comfort enhancement using the proposed strategy.

Development of Integrated Simulation Tool for Jitter Analysis

Pointing stability of high precision observation satellites must satisfy the stringent requirements to perform at a designed level. As even a small vibrational disturbance can result in severe degradation of the optical performance, the effects of inorbit vibrational environment on the performance of optical payload must be predicted and analyzed in the design phase in order to ensure that the requirements imposed on the payload are fully met. In this paper, an integrated framework for the evaluation of the performance of optical payloads is developed. The developed simulation tool comprises of the reaction wheel induced disturbance model, state space model of a structure in modal form and Cassegrain reflector model. The performance degradation of the optical system due to jitter is expressed by using modulation transfer function (MTF) and image simulation. Moreover, vibration isolator model is also added to show the effectiveness of using a vibration isolator for the elimination of the effects of jitter in the acquisition of an image.

Simulation Study of Advanced Variable Displacement Engine Coupled to Power-Split Hydraulic Hybrid Powertrain

The simulation based investigation of the variable displacement engine is motivated by a desire to enable unthrottled operation at part load, and hence eliminate pumping losses. The mechanism modeled in this work is derived from a Hefley engine concept. Other salient features of the proposed engine are turbocharging and cylinder deactivation. The cylinder deactivation combined with variable displacement further expands the range of unthrottled operation, whereas turbocharging increases the power density of the engine and allows downsizing without the loss of performance. Although the proposed variable displacement turbocharged engine (VDTCE) concept enables operations in a very wide range, running near idle is impractical. Therefore, the VDTCE is integrated with a hybrid powertrain to mitigate issues with engine transients and mode transitions. The engine model is developed in AMESim using physics based models, such as thermodynamic cycle simulation, filling and emptying of manifolds, and turbulent flame entrainment combustion. A predictive model of the power-split hydraulic hybrid driveline is created in SIMULINK, thus facilitating integration with the engine. The integrated simulation tool is utilized to address design and control issues, before determining the fuel economy potential of the powertrain comprising a VDTCE engine and a hydraulic hybrid driveline.

Modeling Soft Institutional Change and the Improvement of Freshwater Governance in the Coastal Zone

Mongruel, R., J. Prou, J. Ballé-Béganton, M. Lample, A. Vanhoutte-Brunier, H. Réthoret, J. Pérez Agúndez, F. Vernier, P. Bordenave, and C. Bacher. 2011. Modeling soft institutional change and the improvement of freshwater governance in the coastal zone. Ecology and Society 16(4): 15. https://doi.org/10.5751/ES-04294-160415

Integrating digital manufacturing and simulation tools in the assembly design process: A cooperating robots cell case

This paper addresses the challenges encountered in the process of integrating simulation tools in the process of designing cooperating robots-based assembly cells, particularly focusing on the issues related to the automotive Body in White (BIW) assembly lines. A short overview about cooperating robots is presented, emphasizing on the requirements posed by the increasing need for mass customization in the automotive industry. A novel simulation-based approach is introduced for supporting engineers in the process of designing cooperating robots cells. It is demonstrated in a realistic BIW assembly case. Alternative cell configurations are generated and evaluated in an integrated way. The outlook of the proposed approach against current practice is discussed.

A solution for improved simulation efficiency of a multi-domain marine power system model

Integrated Full Electric Propulsion (IFEP) marine power systems offer increased design flexibility and operational economy by supplying ship propulsion and service loads from a common electrical system. Predicting the behaviour of IFEP systems through simulation is important in reducing the design risk. However, the prevalence of power electronics and the potential for interaction between large electrical and mechanical systems introduce significant simulation challenges. This paper presents an integrated simulation tool, which brings together electrical, mechanical, thermal and hydrodynamic models, facilitating a holistic simulation capability. Approaches adopted for model validation and computational efficiency together with two case studies are discussed.

Simulated yield and quality distribution of sawn timber from final felling in a Norway spruce [Picea abies (L.) Karst.] stand with varying thinning regimes: A case study

An integrated simulation tool, formed by integrating the InnoSIM sawing simulation system with the RetroSTEM simulator, was used to convert available wood raw materials from final felling into sawn timber, allowing for calculation of the three-dimensional wood properties of individual stems (stem geometry, heartwood formation, knottiness) as well as the volume, quality and value of sawn timber in a Norway spruce stand with different thinning regimes (unthinned, normal and intensively thinned). Based on the input data of sawing patterns, the simulations indicate that there are relatively small differences (<8%) in the volume yield (m3ha−1) of sawn goods resulting from sawlogs available from final felling with different thinning practices. However, intensive thinning yielded the largest stem diameters and the greatest volumes (m3ha−1) of large-sized centre goods (thickness: 50, 63, 75 mm) of rather poor quality. Normal thinning yielded the largest volume of A-grade side boards and centre goods (m3ha−1), as well as the best total value (€ha−1) of sawn timber. Differences observed in sawn timber quality distribution can contribute to even more significant variation in value yields, if pricing mechanisms of timber products change to favour higher grade timber products.

A multi-agent architecture for modelling and simulation of small military unit combat in asymmetric warfare

Today’s armed forces, which have a new perspective of combat, are trying to use high-end technologies to improve their capabilities especially in combat and asymmetric warfare. Complexity is the real word to define the future war environment, which will need information about multi dimensional needs. With a continuous increase in the complexity and tempo on the modern battlefield; new demands are placed on rapid and precise information dissemination. The volume of information available to the user becomes larger while the time necessary for correctly interpreting and understanding this information becomes prohibitively smaller. Not only from an informational view but also from other perspectives land combat may be described – mathematically and physically – as a nonlinear dynamical system composed of many interacting semi autonomous and hierarchically organized agent continuously adapting to a changing environment. From this point of view agent based structures are good suited for modeling and simulating complex adaptive systems. This paper proposes a two layer hybrid agent architecture to match the needs of future multi-dimensional warfare. This architecture has an integrated simulation tool to simulate planning results from the cognitive layer via reactive agents. Our work showed us that results gained from this architecture are valid in small unit combat.

Integrated simulation through the source-code coupling of component models from a modular simulation environment into a comprehensive building performance simulation tool

No single building performance simulation program contains sufficient capabilities and flexibility to fully respond to the full complexity of modern building design and analysis. Consequently, considerable efforts and advances have been made to facilitate the integrated use of multiple simulation tools to provide more extensive modelling capabilities. The research reported in this article has made a contribution towards the goal of integrated simulation by focusing on the internal coupling of component models from a modular simulation environment into a comprehensive building performance simulation tool. A flexible and extensible facility has been designed and developed to enable the use of HVAC component models (TYPEs) from the TRNSYS simulation program within the ESP-r simulation platform. With this, the source code for any number of TRNSYS TYPEs can be compiled with the ESP-r source code to produce an integrated simulation tool that possesses greater capabilities than either simulation program alone.

Integrated simulation tool for quality support in the low-volume high-complexity electronics manufacturing domain

Low-volume high-complexity printed circuit board manufacturing is a highly dynamic domain because of prevailing global pressures. In such an evolving environment, quality issues caused by manufacturing defects are the major concern. The generation, detection and elimination of those defects further impact customer requirements and demands. Current practices in terms of identification and solution of quality issues have three major drawbacks: (i) the metrics used are not meaningful; (ii) several manual operations are involved; and (iii) there is no significant decision support. A novel integrated simulation tool for quality support in low-volume electronics manufacturing that overcomes these weaknesses is presented in this paper. The simulation tool supports current needs in the domain, i.e. knowledge capitalisation, waste reduction, right-first-time performance and agility, as well as the domain customer requirements, i.e. lead time, cost, quality and reliability. Quantitative results from a case study are presented as evidence of the usefulness of the tool in a real context. The results show that the approximately 80% non-value-added cost for the product studied is due to just two types of manufacturing defects. This outcome is key for root cause analysis based not only on defect quantity.

Integration of SimSET photon history generator in GATE for efficient Monte Carlo simulations of pinhole SPECT

The authors developed and validated an efficient Monte Carlo simulation (MCS) workflow to facilitate small animal pinhole SPECT imaging research. This workflow seamlessly integrates two existing MCS tools: simulation system for emission tomography (SimSET) and GEANT4 application for emission tomography (GATE). Specifically, we retained the strength of GATE in describing complex collimator/detector configurations to meet the anticipated needs for studying advanced pinhole collimation (e.g., multipinhole) geometry, while inserting the fast SimSET photon history generator (PHG) to circumvent the relatively slow GEANT4 MCS code used by GATE in simulating photon interactions inside voxelized phantoms. For validation, data generated from this new SimSET-GATE workflow were compared with those from GATE-only simulations as well as experimental measurements obtained using a commercial small animal pinhole SPECT system. Our results showed excellent agreement (e.g., in system point response functions and energy spectra) between SimSET-GATE and GATE-only simulations, and, more importantly, a significant computational speedup (up to approximately 10-fold) provided by the new workflow. Satisfactory agreement between MCS results and experimental data were also observed. In conclusion, the authors have successfully integrated SimSET photon history generator in GATE for fast and realistic pinhole SPECT simulations, which can facilitate research in, for example, the development and application of quantitative pinhole and multipinhole SPECT for small animal imaging. This integrated simulation tool can also be adapted for studying other preclinical and clinical SPECT techniques.

TUGAI: An Integrated Simulation Tool for Ecological Assessment of Alternative Water Management Strategies in a Degraded River Delta

The development of ecologically sound water allocation strategies that account for the needs of riverine ecosystems is a pressing issue, especially in semiarid river basins. In the Aral Sea Basin, a search for strategies to mitigate ecological and socioeconomic deterioration has been in process since the early 1990s. The Geographic Information System-based simulation tool TUGAI has been developed to support the policy determination process by providing a simple, problem-oriented method to assess ecological effects of alternative water management strategies for the Amudarya River. It combines a multiobjective water allocation model with simple, spatially explicit statistical and rule-based models of landscape dynamics. Changes in environmental conditions are evaluated by a fuzzy habitat suitability index for Populus euphratica, which is the dominant species of the characteristic riverine Tugai forests. Water management scenarios can be developed by altering spatiotemporal water distribution in the delta area or the amount of water inflow into the delta. Outcomes of scenario analysis are qualitative comparisons of the ecological effects of different options for a time period of up to 28 years. The given approach utilizes different types of knowledge, from quantitative hydrological data to qualitative local expert knowledge. The main purpose of the tool is to integrate the knowledge in a comprehensive way to make it available for discussions on alternative policies in moderated workshops with stakeholders. In this article, the modules of the tool, their integration, and three hypothetical scenarios are presented. Based on the experience gained when developing the TUGAI tool, we propose that the general framework can be transferred to other areas where tradeoffs in water allocation between the environment and other water users are of major concern. The potential for a simulation tool to structure and inform a complex resource management situation by involving local experts and stakeholders in the development of possible future scenarios will become increasingly valuable for transparent and participatory resource management.

Quantitative analysis of the impact of forging operations on fatigue properties of steel components

Forging of metal components induces grain flow orientation, which leads to anisotropic mechanical properties. Therefore, it is critical to describe and take into account this grain flow anisotropy into fatigue life calculation. A new state variable to represent the grain flow orientation is defined and implemented in the finite element code Forge 3® so that forging can be simulated to predict the grain flow in a forged part. When focusing on steels containing malleable inclusions above a critical size, the Murakami equation can be used for describing high cycle fatigue. This criterion is extended to multiaxial fatigue analysis for materials with a grain flow. Therefore, the output of forging simulations in terms of grain flow can be used in anisotropic fatigue analysis. Moreover, residual stresses resulting from forging should also be taken into account to obtain accurate fatigue calculations. Once this integrated simulation tool is developed, a global optimization loop including Forging and Fatigue calculation can be carried out.

Towards Sustainable Electricity Production from Japanese Forestry Residues: Supply Chains Scenarios and Parameters Estimation Model

In planning biomass-based power generation, planners should take into account the different stakeholders along the biomass supply chains, i.e. biomass resources suppliers, transportation, conversion and electricity suppliers etc. The different participants have different concerns and priorities about environmental, social and economical sides of establishing the biomass energy systems, e.g. electricity production from forestry residues. To help the planners fulfill such concerns a study that addresses the different possible scenarios of biomass supply chains and estimating their impacts is needed. Up to our best knowledge, no study has been reported that takes into consideration the different factors affecting the planning process of biomass supply chain systems for the Japanese case. In this context, our study has been developed as a first step toward integrating the planning parameters and their estimation in a single entity. In this paper, we propose a novel framework for estimating cost, CO2 emissions and labors of possible forestry residues supply-chains scenarios. We call our new framework a Cost-Emission-Labor Model (CELM). The proposed CELM approach provides the biomass planners as well as stakeholders with an integrated simulation tool helping them in their decision-making process. A sensitivity analysis was made, based on a given case study, for the proposed CELM. It is found sensitive to efficiency and capacity of the conversion plant when calculating the cost. While for emission calculations, the CELM is also influenced much by conversion plant efficiency, bulk density and CH4 emissions from storage.

Reducing the electricity cost of a Three-Pipe Water Pumping System – a case study using software

Efficient control is often the most cost-effective option to improve on the running cost of a ThreePipe Water Pumping System. However, the effect of changing the control strategy (i.e. on energy consumption) is usually difficult to predict. A new simulation tool, QUICKcontrol, was used to investigate the energy cost savings potential in a Three-Pipe Water Pumping System. The influence of pump scheduling, dam level set points, control parameters and different combinations thereof were investigated. The simulation models were firstly verified with measurements obtained from the existing system to confirm their accuracy for realistic control retrofit simulations. With the aid of the integrated simulation tool, it was possible to predict savings of R195 000 per year with an average 3.8 MW of load shifted out of peak times. These control strategies can be implemented in the pumping system with a direct payback period of less than 6 months.

Towards numerical prototyping of labs-on-chip: modeling for integrated microfluidic devices

This review article presents an overview of some of the tools, techniques and applications of numerical simulation for integrated microfluidic devices. Provided is a broad overview of the different areas to which numerical techniques have been applied in the development of these devices from detailed studies of fundamental microfluidic problems (e.g., species mixing and sample dispersion) to unique approaches that take a more global overview of the entire system. While the majority of the work to date has been in these areas, also reviewed is some recent progress into other equally important areas of microscale transport such as thermal analysis and chemical reactivity and specificity. An overview of the advantages and disadvantages of common numerical techniques is also presented along with a brief discussion of some of the existing numerical tools, focusing on those best suited for microscale transport analysis. As microfluidic devices become increasingly complex, optimal fluidic and transport designs become more and more difficult to do experimentally. Thus, it is believed that future demand in the field will be for highly integrated simulation tools that allow users without a significant computational fluids background to “numerical prototype” highly integrated devices.

A fuzzy habitat suitability index for Populus euphratica in the Northern Amudarya delta (Uzbekistan)

In the Northern Amudarya delta (Uzbekistan), the regulated hydrological regime is one of the main factors determining the ecological state of riverine ecosystems, such as the characteristic tugai forests. Euphratica poplar ( Populus euphratica, syn. ariana) is the dominant tree species of tugai forests in Central Asia. A habitat suitability index for P. euphratica is developed to provide a measure for the evaluation of future water management alternatives as to their effects on the ecological situation in the delta region. The following environmental variables are chosen as determining parameters for habitat suitability: geomorphology, groundwater level and flooding regime (i.e. flooding frequency, timing and duration of the last flooding). Here, flooding frequency is a dynamic variable that reflects the flooding history at a given site. Collected semi-quantitative and qualitative knowledge about the impact of those variables on suitability of a site for P. euphratica is formalised using a fuzzy set approach. The resulting index is implemented in GIS and applied to a test period (1991–1999). The results are compared to the actual distribution of tugai forest in the year 2000 to check their plausibility. By these means a ‘virtual expert’ is created that enables a fast and simple evaluation of the habitat suitability for P. euphratica on a landscape scale. As part of an integrated simulation tool, the HSI shall support the ecological impact assessment of future water management strategies on the Northern Amudarya delta.

CADLIVE System: Map-Based Dynamic Simulation of Biochemical Networks

Figure 1: CADLIVE System.Gene regulatory and metabolic networks within a cellseem too complicated and heterogeneous to convertthem into mathematical models automatically. Somesimulators have primitive converters forchemical reac-tion equations into conventional mass action (CMA)or general mass action (GMA), but such converterscannot necessarily support the complicated biochemi-cal networks. Most simulators edit the mathematicalmodels manually based on their expertise and expe-riences, which requires laborious and time-consumingoperations involved in formulating and debugging. Inorder to convert such complicated biochemical reac-tions into a mathematical model accurately and eciently, we propose the CADLIVE (Computer-Aided Design of LIVing systEms) System (Fig. 1), a software tool for converting biochemical reactionmaps into mathematical models, and analyzing them, with tight integrated development environmentof simulation tools and databases.

An Integrated Simulation Tool for Modeling the Human Circulatory System

This paper presents an integrated simulation of the circulatory system in physiological movement. The large circulatory system model includes principal organs and functional units in modules in which comprehensive physiological changes such as nerve reflexes, temperature regulation, acid/base balance, O 2 /CO 2 balance, and exercise are simulated. A beat-by-beat heart model, in which the corresponding electrical circuit problems are solved by a numerical analytic method, enables calculation of pulsatile blood flow to the major organs. The integration of different perspectives on physiological changes makes this simulation model applicable for the microscopic evaluation of blood flow under various conditions in the human body.