scholarly journals Selection of scenarios in qualitative models: The case of a government tenders model

2013 ◽  
Vol 61 (7) ◽  
pp. 2923-2929
Author(s):  
Štěpán Veselý ◽  
Mirko Dohnal
Keyword(s):  
Basic Principle ◽  
Model Development ◽  
Current Paper ◽  
Qualitative Model ◽  
Qualitative Modeling ◽  
Knowledge Item ◽  
Qualitative Models ◽  
Methodological Paper ◽  
Selection Of

The task of this methodological paper is to clarify the process of selection of scenarios in qualitative models. Articles on qualitative modeling usually do not cover the topic of scenarios selection exhaustively, only the basic operations are (sometimes) described. This lack of detail might lead to confusion and overly simplified understanding of the process of model development when new users meet with qualitative models. We outline the basic principle of consistency, i.e. that scenarios inconsistent with a given knowledge item entered into the qualitative model are discarded from the model. With help of this principle, the vast set of all “imaginable” scenarios (2712in our case) can be reduced to just 7 scenarios in less than 40 steps. A manageable number of scenarios is important to enable interpretation and practical use, e.g. to evaluate concrete tasks and policies. For our demonstration we use our previously published model of government tenders. The current paper can help those who want to understand qualitative models and their development better, it is not restricted to the problem of qualitative modeling of government tenders.

scholarly journals Decision making in goverment tenders: A formalized qualitative model

2012 ◽  
Vol 60 (4) ◽  
pp. 397-406 ◽  
Author(s):  
Štěpán Veselý ◽  
Mirko Dohnal
Keyword(s):  
A Priori ◽  
Oriented Graph ◽  
Relevant Information ◽  
Qualitative Model ◽  
Unsteady State ◽  
Qualitative Modeling ◽  
State Behavior ◽  
Qualitative Models ◽  
Goal Functions ◽  
Available Information

The paper presents a simple formalized qualitative model of government tenders (GTs). Qualitative models use just three values: Positive/Increasing, Zero/Constant and Negative/Decreasing. Such quantifiers of trends are the least information intensive. Qualitative models can be useful, since GT evaluation often includes such goals as e.g. efficiency of public purchasing, and variables as e.g. availability of relevant information or subjectivity of judgment, that are difficult to quantify. Hence, a significant fraction of available information about GTs is not of numerical nature, e.g.if availability of relevant information is decreasing then efficiency of public purchasing is decreasing as well. Such equationless relations are studied in this paper. A qualitative model of the function F(Goals, Variables) is developed. The model has four goal functions, eight variables, and 39 equationless relations. The model is solved and seven solutions, i.e. scenarios are obtained. All qualitative states, including first and second qualitative derivatives with respect to time, of all variables are specified for each scenario. Any unsteady state behavior of the GT model is described by its transitional oriented graph. There are eight possible transitions among seven scenarios. No a priori knowledge of qualitative modeling is required on the reader’s part.

Large qualitative models of complex chemical and bioengineering processes

1991 ◽  
Vol 56 (10) ◽  
pp. 2107-2141 ◽  
Author(s):  
Mirko Dohnal
Keyword(s):  
Case Studies ◽  
Chemical Process ◽  
Ad Hoc ◽  
Chemical Reactor ◽  
Theoretical Background ◽  
Qualitative Model ◽  
Complex Chemical ◽  
Practical Applications ◽  
Qualitative Models ◽  
Decomposition Principle

Qualitative model is a theoretical background of commonsense. Complex qualitative models can have prohibitively many solutions (qualitative states). Therefore a qualitative analogy of such classical quantitative tools as e.g. the decomposition is developed. Practical applications of decomposition principle is nearly always ad hoc. Therefore two case studies are presented in details, a chemical process (mixer, chemical reactor, separator) and an anaerobic fermentor.

scholarly journals Environmental Consequences of Wildlife Tourism: The Use of Formalised Qualitative Models

2015 ◽  
Vol 34 (3) ◽  
pp. 260-267 ◽  
Author(s):  
Štěpán Veselý ◽  
Mirko Dohnal
Keyword(s):  
Significant Fraction ◽  
Qualitative Model ◽  
Composition Change ◽  
Plant Composition ◽  
Environmental Consequences ◽  
Wildlife Tourism ◽  
Qualitative Models ◽  
Available Information

Abstract The paper presents a simple qualitative model of environmental consequences of wildlife tourism. Qualitative models use just three values: Positive/Increasing, Zero/Constant and Negative/Decreasing. Such quantifiers of trends are the least information intensive. Qualitative models can be useful, since models of wildlife tourism include such variables as, for example, Biodiversity (BIO), Animals’ habituation to tourists (HAB) or Plant composition change (PLA) that are sometimes difficult or costly to quantify. Hence, a significant fraction of available information about wildlife tourism and its consequences is not of numerical nature, for example, if HAB is increasing then BIO is decreasing. Such equationless relations are studied in this paper. The model has 10 variables and 20 equationless pairwise interrelations among them. The model is solved and 15 solutions, that is, scenarios are obtained. All qualitative states, including the first and second qualitative derivatives with respect to time, of all variables are specified for each scenario.

Robustness of Parametric and Nonparametric Fitting Procedures of Tree-Stem Taper with Alternative Definitions for Validation Data

2020 ◽  
Vol 118 (6) ◽  
pp. 576-583
Author(s):  
Sheng-I Yang ◽  
Harold E Burkhart
Keyword(s):  
Loblolly Pine ◽  
Model Development ◽  
Data Partitioning ◽  
Parametric Models ◽  
Validation Data ◽  
Data Set ◽  
Stem Taper ◽  
Computationally Intensive ◽  
Tree Stem ◽  
Selection Of

Abstract This study aims to evaluate the robustness of parametric and nonparametric procedures using alternative definitions of validation data for loblolly pine. Specifically, four data division strategies were implemented: random selection of one-third of the trees in the data set, selection of the smallest one-third of the trees by diameter at breast height (DBH), selection of the middle third of the trees by DBH, and selection of the largest third of the trees by DBH. Results indicate that tree taper was predicted reasonably well by both procedures when the smallest, medium-sized, or randomly selected trees were withheld for validation. However, when the largest trees were withheld for validation, diameters predicted by the nonparametric random forest algorithm were considerably less accurate than those predicted by the parametric models, especially for diameters near the tree top. When extrapolation is anticipated, a carefully designed data-partitioning strategy should provide some protection against poor results for given prediction objectives. Study Implications Parametric tree-stem taper models have been widely applied in forestry. Recently, nonparametric methods with computationally intensive algorithms were proposed for estimating tree taper, but reliability of the methods has not been explicitly examined. In practice, models are commonly applied to predict unknown populations, which may vary from the observations used in model development. This study provides insights for natural resource and forest managers to select appropriate validation procedures when developing models for predicting tree-stem taper and examining robustness of parametric and nonparametric fitting of tree-stem taper under varying levels of interpolation/extrapolation from fitting to validation of data.

scholarly journals Procurement Selection Model: Development of a Conceptual Model Based on Transaction Costs

2014 ◽  
Vol 2 (2) ◽  
pp. 56 ◽  
Author(s):  
Mohammed A Rajeh ◽  
John Tookey ◽  
James Rotimi
Keyword(s):  
Transaction Costs ◽  
Construction Projects ◽  
Negative Impact ◽  
Selection Process ◽  
Model Development ◽  
Evaluation Criteria ◽  
Analytical Form ◽  
Model Based ◽  
Suitable Combination ◽  
Selection Of

Procurement is a major improvement area and a crucial element contributing to project success, and the selection of an optimal procurement system is an important and difficult step in project execution. The criteria for choosing suitable procurement methods are based on client’s objectives and priorities, and influenced by project constraints. The procurement path determination chart has largely dominated research in procurement selection process in construction. Eight factors need to be considered by the client when developing procurement selection criteria. At the procurement strategy the focus should be on factors such as cost, quality, and time, while at the procurement route the consideration should focus on complexity, certainty, risk, responsibility, and degree of control by the client. However, including certain criteria and ignoring the magnitude of transaction costs (TCs) associated with uncertainties in the transaction environment simplifies this process. This study addresses this shortcoming by combining evaluation criteria with TCs incurred because of external and internal environmental uncertainties in a theoretical model on procurement selection. This is achieved by developing a conceptual framework model based on TCs. Uncertainties in the transaction environment have a positive or negative impact on the magnitude of TCs such as information, procurement, administration, and enforcement. The model represents an analytical form of a suitable combination of factors influencing procurement systems, which guide procurement decisions. The model will increase understanding of how efficient procurement selection of construction projects can be achieved through appropriate procurement procedures, which could positively impact project performance.Keywords: Construction, Procurement systems, Transaction costs

Application of the Deviate Method of Minimum Subordinative Degree on the Selection of Outstanding Graduates

2014 ◽  
Vol 644-650 ◽  
pp. 6313-6316
Author(s):  
Jin Si ◽  
Hai Zhu Yu ◽  
Xiao Li Chai
Keyword(s):  
College Students ◽  
Basic Principle ◽  
Learning Activities ◽  
Decision Problems ◽  
Important Work ◽  
Universities And Colleges ◽  
Complex Decision ◽  
Selection Of

How to objective, fair, justice, open selection of outstanding graduates is an important work in universities and colleges each year. For college students, the selection of outstanding graduates is the comprehensive consideration of university study and life in the four years, which is critical to the development of future employment and career. First, this paper introduces the basic principle method of minimum subordinative degree, and then considers the effect of college students through a variety of learning activities comprehensively. Finally, application examples are given in the selection of outstanding graduates. The results show that, this method is a good effective tool to solve the fuzzy uncertainly factors for complex decision problems, which has good applicability.

The promises and challenges of using gene mutations for patient stratification in follicular lymphoma

Blood ◽  
2017 ◽  
Vol 130 (13) ◽  
pp. 1491-1498 ◽  
Author(s):  
Oliver Weigert ◽  
David M. Weinstock
Keyword(s):  
Follicular Lymphoma ◽  
Risk Model ◽  
Model Development ◽  
Gene Mutations ◽  
Predictive Biomarkers ◽  
Individual Risk ◽  
Patient Stratification ◽  
Risk Models ◽  
Risk Patients ◽  
Selection Of

Abstract Follicular lymphoma (FL) is a clinically and molecularly highly heterogeneous disease. Most patients achieve long-lasting remissions and have excellent overall survival (OS) with current treatment. However, ∼20% of patients have early progression of disease and short OS. At present, therapies are not guided by individual risk or disease biology. Reliable tools for patient stratification are urgently needed to avoid overtreatment of low-risk patients and to prioritize alternative approaches in high-risk patients. A rapidly expanding repertoire of promising therapeutic options is available for clinical evaluation; however, the numbers of patients with FL and the resources to conduct adequately powered trials are limited. Recent studies have shown that gene mutations can serve as prognostic and/or predictive biomarkers, in particular when integrated into composite risk models. Before translating these findings into routine clinical practice, however, several challenges loom. We review aspects of “clinicogenetic” risk model development and validation that apply to FL and more generally to other cancers. Finally, we propose a crowdsourcing effort that could expedite the development, validation, refinement, and selection of risk models. A new era of collaboration and harmonization is required if we hope to transition from empiric selection of therapeutics to risk-based, biology-guided treatment of patients with FL.

scholarly journals MagmaFOAM-1.0: a modular framework for the simulation of magmatic systems

2021 ◽  
Author(s):  
Federico Brogi ◽  
Simone Colucci ◽  
Jacopo Matrone ◽  
Chiara Paola Montagna ◽  
Mattia De' Michieli Vitturi ◽  
...  
Keyword(s):  
Model Development ◽  
Equilibrium Phase ◽  
Solution Technique ◽  
Computer Performance ◽  
Community Model ◽  
Volcanic Processes ◽  
Rayleigh Taylor Instability ◽  
Basaltic Melts ◽  
Time Selection ◽  
Selection Of

Abstract. Numerical simulations of volcanic processes play a fundamental role in understanding the dynamics of magma storage, ascent and eruption. The recent extraordinary progress in computer performance and improvements in numerical modeling techniques allow simulating multiphase systems in mechanical and thermodynamical disequilibrium. Nonetheless, the growing complexity of these simulations requires the development of flexible computational tools that can easily switch between sub-models and solution techniques. In this work we present MagmaFOAM, a library based on the open source computational fluid dynamics software OpenFOAM, that incorporates models for solving the dynamics of multiphase, multicomponent magmatic systems. Retaining the modular structure of OpenFOAM, MagmaFOAM allows run-time selection of the solution technique depending on the physics of the specific process, and sets a solid framework for in-house and community model development, testing and comparison. MagmaFOAM models thermo-mechanical non-equilibrium phase coupling and phase change, and implements state-of-the-art multiple volatile saturation models and constitutive equations with composition-dependent and space-time local computation of thermodynamic and transport properties. Code testing is performed using different multiphase modeling approches for processes relevant to magmatic systems: Rayleigh-Taylor instability, for buyoancy-driven magmatic processes; multiphase shock tube simulations, propedeutical to conduit dynamics studies; bubble growth and breakage in basaltic melts. Benchmark simulations illustrate the capabilities and potential of MagmaFOAM to account for the variety of non-linear physical and thermodynamical processes characterizing the dynamics of volcanic systems.

scholarly journals Synthesis of a CFD Benchmark Exercise: Examining Fluid Flow and Residence-Time Distribution in a Water Model of Tundish

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5453
Author(s):  
Dong-Yuan Sheng
Keyword(s):  
Best Practice ◽  
Model Development ◽  
Practical Interest ◽  
Turbulence Models ◽  
Fluid Simulation ◽  
Model Verification ◽  
Water Model ◽  
Cfd Simulations ◽  
Cfd Models ◽  
Selection Of

Computational Fluid Dynamics (CFD) has become an indispensable tool that can potentially predict many phenomena of practical interest in the tundish. Model verification and validation (V&V) are essential parts of a CFD model development process if the models are to be used with sufficient confidence in real industrial tundish applications. The crucial aspects of CFD simulations in the tundish are addressed in this study, such as the selection of the turbulence models, meshing, boundary conditions, and selection of discretization schemes. A series of CFD benchmarking exercises are presented serving as selected examples of appropriate modelling strategies. A tundish database, initiated by German Steel Institute VDEH working group “Fluid Mechanics and Fluid Simulation”, was revisited with the aim of establishing a comprehensive set of best practice guidelines (BPG) in CFD simulations for tundish applications. These CFD benchmark exercises yield important results for the sensible application of CFD models and contribute to further improving the reliability of CFD applications in metallurgical reactors.

scholarly journals FORMATION OF THE LEXEME’S CORPUS FOR THE LEVEL MODEL DEVELOPMENT OF LANGUAGE

2019 ◽  
Vol 7 (4) ◽  
pp. 80-84
Author(s):  
Irina A. Kuprieva ◽  
Stanislava B. Smirnova
Keyword(s):  
Model Development ◽  
Internal Flows ◽  
Organizational System ◽  
Cultural Organizations ◽  
Modeling Methods ◽  
Level Model ◽  
External Flows ◽  
Development Of Language ◽  
Theory Of Graphs ◽  
Selection Of

Purpose: The article deals with the principles of selection of factual material on the problem of fixing language invariants and variants. Methodology: This is an analytic-dialectical research in which the data was obtained through the analysis of language and grammar in English texts. Main Findings: As a result of using the system-object method of knowledge representation, a model for securing language variants is constructed. The UFO model of the organizational system can act as a network, production, and frame models. In conclusion, only the internal flows are of interest at the level of the function description, since the algebra of images of the theory of patterns and the theory of graphs are involved in external flows. Applications: This article can be used by regional schools, cultural organizations and universities. Novelty/Originality: In this research, a level model of language invariants and variants was developed and presented. Statistical accounting methods, linguistic and computer modeling methods were used on this model.

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