Conceptual Simulation Model Research Articles

Displacement mechanisms of air injection for IOR in low permeability light oil reservoirs

Air injection into light oil reservoirs has been proven to be a valuable improved oil recovery (IOR) process and is being successfully implemented worldwide in many oilfields. It specially offers unique technical and economic opportunities for tertiary or secondary oil recovery in light oil reservoirs with low permeability in which conventional water injection techniques have been unsuccessful and/or uneconomical. This paper provides a comprehensive overview on the oxidation and IOR process of air injection into low permeability light oil reservoir based on detailed analysis of some field projects and the results of laboratory testing and reservoir simulation of a typical light oil reservoir, the Q131 Block. The reaction mechanisms of low temperature oxidation (LTO) and high temperature oxidation (HTO or in-situ combustion) are particularly addressed in this study. Air flooding displacement efficiency experiment was carried out without water injection, and an oil recovery of more than 40% of hydrocarbon pore volume (HCPV) was observed. A series of high-pressure oxidation experiments using the typical light oil were conducted in the temperature range of 98°C to 180°C. The results showed high oxidation and carbon dioxide (CO2) conversion rates, which are both favourable in terms of oxygen consumption. A conceptual full field compositional reservoir simulation model of the targeted low permeability block was also used to examine the reaction schemes, thermal effect of LTO reactions and IOR mechanisms. [Received: March 22, 2014; Accepted: February 7, 2016]

Assuming it is all about conditions. Framing a simulation model for complex, adaptive urban space

In this paper, we explore the route beyond the conventional, linear attitude within planning and its rationality debate. We combine our theoretical reasoning with a multiscale approach and with fractal-like argumentation which results in a frame of conditions which is supported by the outline of a theoretical conceptual simulation model which would also allow non-linear, iterative simulations of the urban space. The understanding of autonomous non-linear spatial development has a direct impact on planning. Addressing the underlying thinking behind Haken’s synergetics we develop a framework within which the interdependencies between different levels of scale are key. We are aware that bottom-up and top-down processes often have a mutual influence on one another. We therefore propose a conceptual simulation model for planning where conditions have an impact at various levels of scale. In coherence with the idea of the ‘dynamic behaviour of the system after a planning decision was made’, this feedback gives us information on the surviving and non-surviving planning scenarios and decisions and is reminiscent of systems which are open to self-organizing pattern formation. Our reasoning with regard to planning and decision-making and their multilevel consequences is strongly influenced by the arguments presented in complexity studies.

RTI (“Real-Time Incentives”) outperforms traditional management in a simulated mixed fishery and cases incorporating protection of vulnerable species and areas

The recently proposed ‘Real-Time Incentive (RTI)’ fisheries-management approach replaces catch or landings quotas and days-at-sea limitations with a single allowance of fishing-impact credits (‘RTIs’). According to this concept, fishing mortality rates of multiple species and impacts on the ecosystem are regulated through a single ‘currency’. Fishers can fish where and when they want and spend their allocated RTIs according to spatiotemporally varying tariffs. Managers set the tariffs based on agreed target mortality rates of multiple species, using knowledge of the spatiotemporally varying catchabilities of the various species caught or impacted in a mixed fishery. We explore algorithms for combining real-time CPUE data of up to four different species in a conceptual simulation model. The simulations indicate that RTI may perform better than several traditional management systems, such as broad-brush effort restrictions, Total Allowable Catches and Total Allowable Landings, in terms of controlling harvest rates of several species in a mixed fishery with differing catchabilities, while at the same time limiting impact on a vulnerable species or ecosystem elements. Performance weakens with greater spatial overlap of the ‘choke’ and other species, and also when fish migrate. Real-time updating requires that local CPUE levels in a given time step are predictive of catchabilities in the following time step. Historical information may be more accurate than real-time information if migration patterns are similar year-on-year. RTI allows the fishers to derive the balance between limiting mortality on choke and vulnerable species and optimally exploiting others because it internalises the cost of undesirable outcomes. In the light of the Ecosystem Based Approach to Fisheries Management, and in particular in the context of the European Union landings obligation, the integrated RTI fisheries management approach could offer a practical solution that addresses some of the problems inherent in a multi-objective fishery system. RTI is ready for case-specific testing.

OTA-Grapes: A Mechanistic Model to Predict Ochratoxin A Risk in Grapes, a Step beyond the Systems Approach

Ochratoxin A (OTA) is a fungal metabolite dangerous for human and animal health due to its nephrotoxic, immunotoxic, mutagenic, teratogenic and carcinogenic effects, classified by the International Agency for Research on Cancer in group 2B, possible human carcinogen. This toxin has been stated as a wine contaminant since 1996. The aim of this study was to develop a conceptual model for the dynamic simulation of the A. carbonarius life cycle in grapes along the growing season, including OTA production in berries. Functions describing the role of weather parameters in each step of the infection cycle were developed and organized in a prototype model called OTA-grapes. Modelling the influence of temperature on OTA production, it emerged that fungal strains can be shared in two different clusters, based on the dynamic of OTA production and according to the optimal temperature. Therefore, two functions were developed, and based on statistical data analysis, it was assumed that the two types of strains contribute equally to the population. Model validation was not possible because of poor OTA contamination data, but relevant differences in OTA-I, the output index of the model, were noticed between low and high risk areas. To our knowledge, this is the first attempt to assess/model A. carbonarius in order to predict the risk of OTA contamination in grapes.

Modelling metabolism based performance of an urban water system using WaterMet2

This paper presents a new quantitative model called ‘WaterMet2’ for the metabolism based assessment of the integrated urban water system (UWS) performance. WaterMet2 quantifies a number of UWS flows/fluxes (e.g. water and energy) which can be used to derive sustainability-based performance metrics. The generic WaterMet2 model overcomes the drawbacks of the existing UWS models and strives to bridge the gaps related to the nexus of water, energy and other environmental impacts in an integrated UWS. The main features of WaterMet2 are: (1) conceptual simulation model of UWS comprised of water supply, stormwater and wastewater subsystems with possible centralised and decentralised water reuse; (2) UWS represented by an arbitrary number of key UWS components for each type in four spatial scales (System, Subcatchment, Local and Indoor areas) in a distributed modelling type approach; (3) quantifying the metabolism-based performance of UWS including the caused and avoided environmental impact categories (GHG emissions, acidification and eutrophication potentials) and resource recovery in UWS. WaterMet2 is tested, validated and demonstrated by evaluating the long-term performance of the UWS of a northern European city for three states including business as usual and two intervention strategies: addition of new water resources and large scale localised water recycling. The results obtained demonstrate the effectiveness of WaterMet2 in evaluating the sustainability related UWS performance, the suitability of using WaterMet2 at the strategic level UWS planning and the importance of using an integrated assessment approach covering the full urban water cycle.

Test of newly developed conceptual hydrological model for simulation of rain-on-snow events in forested watershed

A conceptual hydrological model that links the Xin'anjiang hydrological model and a physically based snow energy and mass balance model, described as the XINSNOBAL model, was developed in this study for simulating rain-on-snow events that commonly occur in the Pacific Northwest of the United States. The resultant model was applied to the Lookout Creek Watershed in the H. J. Andrews Experimental Forest in the western Cascade Mountains of Oregon, and its ability to simulate streamflow was evaluated. The simulation was conducted at 24-hour and one-hour time scales for the period of 1996 to 2005. The results indicated that runoff and peak discharge could be underestimated if snowpack accumulation and snowmelt under rain-on-snow conditions were not taken into account. The average deterministic coefficient of the hourly model in streamflow simulation in the calibration stage was 0.837, which was significantly improved over the value of 0.762 when the Xin'anjiang model was used alone. Good simulation performance of the XINSNOBAL model in the WS10 catchment, using the calibrated parameter of the Lookout Creek Watershed for proxy-basin testing, demonstrates that transplanting model parameters between similar watersheds can provide a useful tool for discharge forecasting in ungauged basins.

Framework of a Conceptual Simulation Model Design Tool

Computer simulation is an efficient tool for addressing problems related to complex systems. To ensure a successful simulation study, a systematic project management is the most important factor. This initially requires a proper conceptual model design. However, the importance of a precise conceptual model design is often overlooked, and there is currently no conceptual design tool for field engineers. To address this problem, this paper proposes a framework for a conceptual simulation model design support tool that includes an automatic model generation feature. The components of the conceptual model are defined, and the proper conceptual model design process is examined to present the desirable development concept of the conceptual model design support tool.

Simulation and Interpretation: A Research Note on Utilizing Qualitative Research in Agent-Based Simulation

The paper provides a summarizing review of our research on integrating qualitative methodologies in agentbased social simulation. This holds for both the development of behavioural rules for software agents as well as for interpreting simulation results. Specifically we rely on Grounded Theory, a well-established methodology in qualitative social research. Development of agent rules relies on open coding in a Grounded Theory approach. Interpreting simulation results in a coherent story line relies on theoretical coding in a Grounded Theory approach. This is demonstrated at two examples: the first example shows how qualitative textual data is transformed in a conceptual model for agent-based simulation. The second example shows how numerical simulation results reveal a story line of a case. For this purpose the concept of stylized facts is consulted.

Integrating soft systems methodology to aid simulation conceptual modeling

AbstractDiscrete‐event simulation is considered an increasingly common support tool for decision making, especially in manufacturing. Most simulation projects are divided into three distinct phases: conception, implementation, and analysis. Some authors believe the conception phase is the most important, as the simulation study objectives are defined and the project's foundation is laid at this point. Many researchers do not spend the necessary amount of time on this important initial phase. Thus, this article presents an integration method that makes use of soft systems methodology (SSM), a complex problem‐solving approach, during the conceptual phase of simulation studies. SSM was used throughout the conceptual modeling phase for a real manufacturing simulation case study. Through the analysis of this study, it can be concluded that the use of SSM to develop the conceptual model enabled identification of the study objectives, thus avoiding errors and reworks. The study's results are presented and the method's application is justified by presenting a valid model capable of analyzing the system's key input variables.

An agent‐based simulation model to assess the impacts of introducing a shared‐taxi system: an application to Lisbon (Portugal)

SummaryThis paper presents a new concept of urban shared‐taxi services. The proposed system has a new organisational design and pricing scheme that aims to use the capacity in traditional taxi services in a more efficient way. In this system, a taxi acting in ‘sharing’ mode offers lower prices to its clients, in exchange for them to accept sharing the vehicle with other persons who have compatible trips (time and space). The paper proposes and tests an agent‐based simulation model in which a set of rules for space and time matching between a request of a client and the candidate shared taxis is identified. It considers that the client is only willing to accept a maximum deviation from his or her direct route and establishes an objective function for selecting the best candidate taxi. The function considers the minimum travel time combination of pickup and drop‐off of all the pool of clients sharing each taxi while allowing to establish a policy of bonuses to competing taxis with certain number of occupants. An experiment for the city of Lisbon is presented with the objectives of testing the proposed simulation conceptual model and showing the potential of sharing taxis for improving mobility management in urban areas. Results show that the proposed system may lead to significant fare and travel time savings to passengers, while not jeopardising that much the taxi revenues. Copyright © 2014 John Wiley & Sons, Ltd.

Enhanced Oil Recovery in Gasflooded Carbonate Reservoirs by Wettability-Altering Surfactants

Summary Gas-aided gravity drainage is a common oil-recovery technique in anticline-shaped oil reservoirs. If the permeability is low and the reservoir is oil-wet, the remaining oil saturation can be quite high. The goal of this work is to mobilize a part of this oil by surfactant injection. An anionic-surfactant formulation was developed to alter wettability and lower interfacial tension (IFT) for a gasflooded, carbonate reservoir. Different coreflood strategies, including gas/water/surfactant/water (GWSW), gas/surfactant/gas (GSG), gas/surfactant/water (GSW), and gas/surfactant/water/gas (GSWG) floods, were investigated. GSG, GWSW, and GSWG corefloods conducted in limestone cores recovered an additional 40–50% of the original oil in place (OOIP) because of the injection of surfactant. GSW corefloods conducted in a vuggy dolomite recovered less: an approximately 20%-of-OOIP incremental recovery. Numerical simulation was used to match GSG and GSW corefloods and estimate multiphase-flow functions. A 2D conceptual simulation model using these functions was built for an anticline reservoir for gas and surfactant-solution injection. GSG flooding using wettability-altering surfactant exhibited high oil recovery at the field scale. IFT reduction, wettability alteration, and foam formation contributed to enhanced oil recovery (EOR).

Space: the final frontier

book reviews ISSN 1948-6596 Space: the final frontier Spatial Simulation: Exploring Pattern and Process. David O’Sullivan & George L. W. Perry, 2013, Wiley–Blackwell. 305 pp. £85.00 (hardback) / £39.95 (paprback) ISBN: 9781119970804 / 9781119970798; http://eu.wiley.com In 1994, a special feature in Ecology highlighted the prominent role of space in ecological theory and emphasized that for many ecologists, spatial complications were used as a catch-all for explain- ing away surprising results (Kareiva 1994). And indeed, Volker Grimm reiterates in the foreword of ‘Spatial Simulation’ by O’Sullivan & Perry that there is still ‘no general theory’ of how space mat- ters. However, while Kareiva complained that there were no serious experiments testing spatial theory, O’Sullivan and Perry complain 20 years later that there is no general theory. Conse- quently, their book is about simulation (something which might be considered to be between theory and experiments) of spatial patterns and proc- esses with an emphasis on three broad categories: aggregation and segregation, random walk and mobile entities, and growth and percolation. For each of these categories the book provides sys- tematic and comprehensive overviews of simple, generic models that can be used as building blocks for more complex and specific models. Through- out the book, well-developed examples are dis- cussed and implemented in the free software Net- Logo (Wilensky 1999). A companion webpage pro- vides the reader with a model zoo, i.e. all simula- tion models chapter-by-chapter, ready to be in- vestigated and explored by the interested reader, potential user and developer. Covering examples across a wide range of disciplines that comprise the contemporary social and environmental sciences from archaeology to urban geography, O’Sullivan and Perry’s general introductory chapters are very helpful in order to understand the various concepts, definitions and tools necessary to simulate complex spatiotempo- ral patterns and processes. I particularly liked their emphasis on the heuristic value of constructing spatial simulation models. Rather than emphasiz- ing predictions, which may never be possible be- cause of non-linearities and stochasticity leading to deterministic chaos, spatial simulation models play a great role in exploring complex aspects and increasing our understanding of spatial patterns and processes. My own background is in plant ecology and an armada of conceptual, analytical and virtual spatial simulation models have been proposed for example to model the dynamics of forest communities or to explain species coexis- tence at spatial scales from local to global. What we are still lacking is a systematic overview of core ideas and concepts. O’Sullivan and Perry’s first two chapters really help to tame ‘the bewildering array of ideas’ (Chesson 2000) in the context of spatial simulation models. The book may even contribute substantially to promoting consistent terminology and to ordering or organizing key concepts of spatial simulation models more for- mally. After covering the basic building-block mod- els (e.g. interacting particle systems, random walks, percolation and growth) quite comprehen- sively in chapters 3–5, the remaining chapters cover the various possibilities for representing space and time and put things into perspective by considering model uncertainty and evaluation (one of the best and most useful chapters). The two final chapters weave things together using the example of island resource exploitation by hunter-gatherers and provide an overall conclud- ing chapter summarizing the main conceptual ideas and themes (i.e. utility of building-block ap- proach, challenge of inferring process from pat- tern, need for careful evaluation of spatial simula- tion models). Overall, this book and its associated web- page provide a very thorough and comprehensive starting point for students and researchers from various fields who might seriously consider adding a spatial component to their empirical or model- ling work in order to answer their specific ques- tions. There were, however, two points which I did not like very much. First, the authors promise to cover important points in some places, but frontiers of biogeography 6.2, 2014 — © 2014 the authors; journal compilation © 2014 The International Biogeography Society

A modelling study of long term green roof retention performance

This paper outlines the development of a conceptual hydrological flux model for the long term continuous simulation of runoff and drought risk for green roof systems. A green roof's retention capacity depends upon its physical configuration, but it is also strongly influenced by local climatic controls, including the rainfall characteristics and the restoration of retention capacity associated with evapotranspiration during dry weather periods. The model includes a function that links evapotranspiration rates to substrate moisture content, and is validated against observed runoff data. The model's application to typical extensive green roof configurations is demonstrated with reference to four UK locations characterised by contrasting climatic regimes, using 30-year rainfall time-series inputs at hourly simulation time steps. It is shown that retention performance is dependent upon local climatic conditions. Volumetric retention ranges from 0.19 (cool, wet climate) to 0.59 (warm, dry climate). Per event retention is also considered, and it is demonstrated that retention performance decreases significantly when high return period events are considered in isolation. For example, in Sheffield the median per-event retention is 1.00 (many small events), but the median retention for events exceeding a 1 in 1 yr return period threshold is only 0.10. The simulation tool also provides useful information about the likelihood of drought periods, for which irrigation may be required. A sensitivity study suggests that green roofs with reduced moisture-holding capacity and/or low evapotranspiration rates will tend to offer reduced levels of retention, whilst high moisture-holding capacity and low evapotranspiration rates offer the strongest drought resistance.

EHSM: a conceptual ecohydrological model for daily streamflow simulation

AbstractA parsimonious conceptual lumped model is here presented with the aim of simulating daily streamflow in semi‐arid areas. The model, processing daily rainfall and reference evapotranspiration at basin scale, reproduces surface and subsurface runoff, soil moisture dynamics, and actual evapotranspiration fluxes. The key elements of this numerical model are the soil bucket, where rainfall, evapotranspiration, and leakage drive soil moisture dynamics, and two linear reservoirs working in parallel with different characteristic response times. The surface reservoir, able to simulate the fast response of the basin, is fed by rain falling on impervious area and by runoff generated with excess of saturation mechanism, whereas the deep reservoir, which simulates the slow response, is fed by instantaneous leakage pulses coming from the soil bucket. Seven model parameters, which summarize soil, vegetation, and hydrological catchment properties, are assessed on a Sicilian basin, first using simple basic ecohydrological knowledge and then Monte Carlo simulations as well.The proposed model provides reliable estimate of daily runoff, accurate reproduction of flow duration curve, and physically consistent traces of soil moisture and evapotranspiration fluxes. Model performances are comparable in the two cases of calibrated and ecohydrologically driven parameters, emphasizing how basic descriptors are able to provide runoff estimation. Copyright © 2013 John Wiley & Sons, Ltd.

Evaluation of a novel fuzzy method and a conceptual model for a long-term daily streamflow simulation

HEC-HMS (Hydrologic Modeling System) has been designed by HEC (Hydrologic Engineering Center) for simulation of precipitation-runoff processes in a drainage basin. In this study, HEC-HMS as a conceptual model is compared with an Active Learning Method (ALM) as a novel fuzzy model for long term simulation of daily streamfl ow in Karoon III basin, Iran. The daily discharge data from 1991 to 1996 and from 1996 to 1999 were uti- lized for 'calibration and training' and 'validation and testing' the model approach, respectively. In addition, HEC- HMS was implemented using its new loss module (SMA, Soil Moisture Account).The following statistical error measures were determined for the validated conceptual model: the Nash-Sutcliffe (model effi ciency) 0.8, Bias 36 m 3 s -1 , R 2 0.84, MPAE (Mean Percent of Absolute Error) 36.5 % and PTVE (Percent of Total Volume Error) 11.3 %. These error measures for the ALM model with 32 fuzzy rules were Nash-Sutcliffe = 0.75, Bias = 1.3 m 3 s -1 , R 2 = 0.75, MPAE = 13 %, and PTVE = 0.46 %. Results of this study demonstrated acceptable streamfl ow simulation by HEC-HMS (with SMA module) and ALM for the continuous streamfl ow modeling. In addition, training of the ALM is easier and more straight forward than the training of other artifi cial intelligence models, thus ALM appears suitable to be introduced as a new modeling method for streamfl ow simulation.

A conceptual grey rainfall-runoff model for simulation with uncertainty

This paper presents an approach based on grey numbers to represent the total uncertainty of a conceptual rainfall-runoff model. Using this approach, once the grey numbers representing the model parameters have been properly defined, it is possible to obtain simulated discharges in the form of intervals (grey numbers) whose envelope defines a band which represents the total model uncertainty. The application to a real case showed that the construction of this band, according to a rigorous application of grey number theory, involves long computational times. However, these times can be significantly reduced using a simplified computing procedure with minimal approximations in the quantification of the simulated grey discharge. Relying on this simplified procedure, the conceptual rainfall-runoff grey model was then calibrated in order to respect a predefined level of model uncertainty, i.e. the band obtained from the envelope of simulated grey discharges had to include an assigned percentage of observed discharges and was at the same time as narrow as possible. Finally, the uncertainty bands were compared with the ones obtained using a well-established approach for characterising uncertainty, the Generalised Likelihood Uncertainty Estimation (GLUE) method. The results of the comparison showed that the proposed approach may represent a valid tool for characterising the total uncertainty of a rainfall-runoff model.

Prediction of Groundwater Inundation Based on GMS - With Example of Inundation-Affected Areas in Upstream of Dadingzishan Reservoir

To deal with specific groundwater inundation problems such as large-scale study area, complicated recharge and discharge terms and special aquifer structures, there may be some inappropriateness or limitation in accuracy, range or flexibility when using traditional methods, including the experience analysis method, water balance method and the principle of Hydrodynamics. However, the numerical modeling method, which can break the constraints of space, time and accuracy, can conquer the problems above, even though there have been very few utilizations of the numerical simulation method on inundation prediction. With the real case of the inundation-affected areas located in the upstream of the Dadingzishan Reservoir, firstly, it analyzed and listed out the major controlling elements, including fundamental controlling elements (location and range, topography, land utilization, hydrology and meteorology, reservoir operation, and human activities, etc.) and key controlling elements (structures, boundaries, functions, input features of the aquifer) in this paper. Secondly, a hydrogeological conceptual model and numerical simulation model had been established to serve for the prediction of inundation range and degree. After the identification and verification of the model and calculating the future recharge and discharge, the fully qualified model had made a forecasting of the inundation situations in 2015 and 2020. This paper is expected to provide practical example and method application for the relative reservoir inundation research.

Possible Impacts of Climate Change on Daily Streamflow and Extremes at Local Scale in Ontario, Canada. Part I: Historical Simulation

The paper forms the first part of an introduction to possible impacts of climate change on daily streamflow and extremes in the Province of Ontario, Canada. In this study, both conceptual and statistical streamflow simulation modeling theories were collectively applied to simulate daily streamflow volumes. Based on conceptual rainfall-runoff modeling principle, the predictors were selected to take into account several physical factors that affect streamflow, such as (1) current and previous quantities of rainfall over the watershed, (2) an index of pre-storm moisture conditions, (3) an index of pre-storm evapotranspiration capacities, and (4) a seasonal factor representing seasonal variation of streamflow volume. These rainfall-runoff conceptual factors were applied to an autocorrelation correction regression procedure to develop a daily streamflow simulation model for each of the four selected river basins. The streamflow simulation models were validated using a leave-one-year-out cross-validation scheme. The simulation models identified that the explanatory predictors are consistent with the physical processes typically associated with high-streamflow events. Daily streamflow simulation models show that there are significant correlations between daily streamflow observations and model validations, with model R2s of 0.68-0.71, 0.61-0.62, 0.71-0.74, and 0.95 for Grand, Humber, Upper Thames, and Rideau River Basins, respectively. The major reason for the model performance varying across the basins might be that rainfall-runoff response time and physical characteristics differ significantly among the selected river basins. The results suggest that streamflow simulation models can be used to assess possible impacts of climate change on daily streamflow and extremes at a local scale, which is major objective of a companion paper (Part II).

Validation in the agent-based modelling paradigm: problems and a solution

This paper identifies problems in Agent-Based Modelling (ABM) validation and proposes a new modelling framework and diagramming technique to help solve those problems. The new framework relates the level of understanding of a real system with the appropriate model validation emphasis. The new diagramming technique, called the Conceptual Model for Simulation (CM4S) Diagram, is designed specifically for developing and documenting the conceptual model of a simulation while capturing appropriate validation criteria. An ABM simulation with real military implications is replicated in a proof of concept study. This paper advances ABM by identifying and helping to solve ABM validation challenges.

Achieving reusability and composability with a simulation conceptual model

Reusability and composability (R&C) are two important quality characteristics that have been very difficult to achieve in the Modelling and Simulation (M&S) discipline. Reuse provides many technical and economical benefits. Composability has been increasingly crucial for M&S of a system of systems, in which disparate systems are composed with each other. The purpose of this paper is to describe how R&C can be achieved by using a simulation conceptual model (CM) in a community of interest (COI). We address R&C in a multifaceted manner covering many M&S areas (types). M&S is commonly employed where R&C are very much needed by many COIs. We present how a CM developed for a COI can assist in R&C for the design of any type of large-scale complex M&S application in that COI. A CM becomes an asset for a COI and offers significant economic benefits through its broader applicability and more effective utilization.