http://hdl.handle.net/2117/6166 Wed, 19 Jun 2013 21:51:30 GMT 2013-06-19T21:51:30Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/17807 Title: Linking quality attributes and constraints with architectural decisions Authors: Ameller, David; Franch Gutiérrez, Javier Abstract: Quality attributes and constraints are among the principal drivers in architectural decision making processes. Quality attributes are improved or damaged by architectural decisions, while constraints directly include or exclude parts of the architecture (e.g., logical components or technologies). We may determine the impact of an architectural decision in the software quality, or which parts of the architecture are a ected by a constraint, but the hard problem is to know if we are respecting the quality requirements (requirements over the quality attributes) and the imposed constraints with all the architectural decisions made. Currently, the most usual approach is that architects use their own experience to produce software architectures that comply with the expected quality requirements and imposed constraints, but at the end, especially for crucial decisions, the architect has to deal with complex tradeo s between quality attributes and juggle with possible incompatibilities raised by the imposed constraints. To facilitate this task and make architect's decision making processes more reliable and e ective, in this paper we present the Quark method to guide the architects in the software architecture design. Quark relies on a specialized ontology, Arteon, which is in charge of managing the architectural knowledge. The decisional part of Arteon is also presented in this paper. Mon, 18 Feb 2013 08:48:53 GMT http://hdl.handle.net/2117/17807 2013-02-18T08:48:53Z Ameller, David; Franch Gutiérrez, Javier no Quality attributes and constraints are among the principal drivers in architectural decision making processes. Quality attributes are improved or damaged by architectural decisions, while constraints directly include or exclude parts of the architecture (e.g., logical components or technologies). We may determine the impact of an architectural decision in the software quality, or which parts of the architecture are a ected by a constraint, but the hard problem is to know if we are respecting the quality requirements (requirements over the quality attributes) and the imposed constraints with all the architectural decisions made. Currently, the most usual approach is that architects use their own experience to produce software architectures that comply with the expected quality requirements and imposed constraints, but at the end, especially for crucial decisions, the architect has to deal with complex tradeo s between quality attributes and juggle with possible incompatibilities raised by the imposed constraints. To facilitate this task and make architect's decision making processes more reliable and e ective, in this paper we present the Quark method to guide the architects in the software architecture design. Quark relies on a specialized ontology, Arteon, which is in charge of managing the architectural knowledge. The decisional part of Arteon is also presented in this paper. http://hdl.handle.net/2117/17065 Title: Conducting empirical studies on reference architectures in IT consulting firms Authors: Martínez Fernández, Silverio Juan; Ameller, David; Ayala Martínez, Claudia Patricia; Franch Gutiérrez, Javier; Terradellas Fernandez, Xavier Abstract: Tight time-to-market needs pushes IT consulting firms (ITCFs) to continuously look for techniques to improve their IT services in general, and the design of software architectures in particular. The use of reference architectures allows ITCFs reusing architectural knowledge and components in a systematic way. In return, ITCFs face the need to assess these reference architectures in order to ensure their quality, return on investment and incremental improvement. Little support exists to help ITCFs to face this challenge. In this work-in-progress paper we present an empirical framework aimed to assess ITCFs’ reference architectures and their use in IT projects by harvesting relevant evidence from the wide spectrum of involved stakeholders. We are currently applying this framework in an ITCF and we report the issues found so far. Mon, 03 Dec 2012 16:49:36 GMT http://hdl.handle.net/2117/17065 2012-12-03T16:49:36Z Martínez Fernández, Silverio Juan; Ameller, David; Ayala Martínez, Claudia Patricia; Franch Gutiérrez, Javier; Terradellas Fernandez, Xavier no Tight time-to-market needs pushes IT consulting firms (ITCFs) to continuously look for techniques to improve their IT services in general, and the design of software architectures in particular. The use of reference architectures allows ITCFs reusing architectural knowledge and components in a systematic way. In return, ITCFs face the need to assess these reference architectures in order to ensure their quality, return on investment and incremental improvement. Little support exists to help ITCFs to face this challenge. In this work-in-progress paper we present an empirical framework aimed to assess ITCFs’ reference architectures and their use in IT projects by harvesting relevant evidence from the wide spectrum of involved stakeholders. We are currently applying this framework in an ITCF and we report the issues found so far. http://hdl.handle.net/2117/16970 Title: A reuse-based economic model for software reference architectures Authors: Martínez Fernández, Silverio Juan; Ayala Martínez, Claudia Patricia; Franch Gutiérrez, Javier Abstract: The growing size and complexity of software systems, together with critical time-to-market needs, demand new software engineering approaches for software development. To remain competitive, organizations are challenged to make informed and feasible value-driven design decisions in order to ensure the quality of the systems. However, there is a lack of support for evaluating the economic impact of these decisions with regard to software reference architectures. This damages the communication among architects and management, which can result in poor decisions. This paper aims at opening a path in this direction by presenting a pragmatic preliminary economic model to perform cost-benefit analysis on the adoption of software reference architectures as key asset for optimizing architectural decision-making. A preliminary validation based on a retrospective study showed the ability of the model to support a cost-benefit analysis presented to the management of an IT consulting company. Tue, 20 Nov 2012 11:11:40 GMT http://hdl.handle.net/2117/16970 2012-11-20T11:11:40Z Martínez Fernández, Silverio Juan; Ayala Martínez, Claudia Patricia; Franch Gutiérrez, Javier no The growing size and complexity of software systems, together with critical time-to-market needs, demand new software engineering approaches for software development. To remain competitive, organizations are challenged to make informed and feasible value-driven design decisions in order to ensure the quality of the systems. However, there is a lack of support for evaluating the economic impact of these decisions with regard to software reference architectures. This damages the communication among architects and management, which can result in poor decisions. This paper aims at opening a path in this direction by presenting a pragmatic preliminary economic model to perform cost-benefit analysis on the adoption of software reference architectures as key asset for optimizing architectural decision-making. A preliminary validation based on a retrospective study showed the ability of the model to support a cost-benefit analysis presented to the management of an IT consulting company. http://hdl.handle.net/2117/16928 Title: EU-Rent as an artifact-centric process model: technical report Authors: Estañol Lamarca, Montserrat; Queralt Calafat, Anna; Sancho Samsó, María Ribera; Teniente López, Ernest Abstract: Business process modeling using an artifact-centric approach has raised a significant interest over the last few years. This approach is usually stated in terms of the BALSA framework which defi nes the four dimensions of an artifact-centric business process model: Business Artifacts, Lifecycles, Services and Associations. One of the research challenges in this area is looking for diff erent diagrams to represent these dimensions. Bearing this in mind, this technical report shows how various UML diagrams can be used to represent all the elements in the BALSA framework by applying them to the EU-Rent case study. Thu, 15 Nov 2012 11:21:28 GMT http://hdl.handle.net/2117/16928 2012-11-15T11:21:28Z Estañol Lamarca, Montserrat; Queralt Calafat, Anna; Sancho Samsó, María Ribera; Teniente López, Ernest no business artifacts, BALSA framework, business process modeling, UML Business process modeling using an artifact-centric approach has raised a significant interest over the last few years. This approach is usually stated in terms of the BALSA framework which defi nes the four dimensions of an artifact-centric business process model: Business Artifacts, Lifecycles, Services and Associations. One of the research challenges in this area is looking for diff erent diagrams to represent these dimensions. Bearing this in mind, this technical report shows how various UML diagrams can be used to represent all the elements in the BALSA framework by applying them to the EU-Rent case study. http://hdl.handle.net/2117/16746 Title: Validation of schema mappings with nested queries Authors: Rull Fort, Guillem; Farré Tost, Carles; Teniente López, Ernest; Urpí Tubella, Antoni Abstract: With the emergence of the Web and the wide use of XML for representing data, the ability to map not only flat relational but also nested data has become crucial. The design of schema mappings is a semi-automatic process. A human designer is needed to guide the process, choose among mapping candidates, and successively refine the mapping. The designer needs a way to figure out whether the mapping is what was intended. Our approach to mapping validation allows the designer to check whether the mapping satisfies certain desirable properties. In this paper, we focus on the validation of mappings between nested relational schemas, in which the mapping assertions are either inclusions or equalities of nested queries. We focus on the nested relational setting since most XML’s Document Type Definitions (DTDs) can be represented in this model. We perform the validation by reasoning on the schemas and mapping definition. We take into account the integrity constraints defined on both the source and target schema. Wed, 17 Oct 2012 14:36:56 GMT http://hdl.handle.net/2117/16746 2012-10-17T14:36:56Z Rull Fort, Guillem; Farré Tost, Carles; Teniente López, Ernest; Urpí Tubella, Antoni no Schema mapping, Nested relational model, Nested query, Query equality, Query inclusion, Validation With the emergence of the Web and the wide use of XML for representing data, the ability to map not only flat relational but also nested data has become crucial. The design of schema mappings is a semi-automatic process. A human designer is needed to guide the process, choose among mapping candidates, and successively refine the mapping. The designer needs a way to figure out whether the mapping is what was intended. Our approach to mapping validation allows the designer to check whether the mapping satisfies certain desirable properties. In this paper, we focus on the validation of mappings between nested relational schemas, in which the mapping assertions are either inclusions or equalities of nested queries. We focus on the nested relational setting since most XML’s Document Type Definitions (DTDs) can be represented in this model. We perform the validation by reasoning on the schemas and mapping definition. We take into account the integrity constraints defined on both the source and target schema. http://hdl.handle.net/2117/16708 Title: Specialization in i* strategic rationale diagrams Authors: López Cuesta, Lidia; Franch Gutiérrez, Javier; Marco Gómez, Jordi Abstract: The specialization relationship is offered by the i* modeling language through the is-a construct defined over actors (a subactor is-a superactor). Although the overall meaning of this construct is highly intuitive, its semantics of strategic rationale (SR) diagrams is not defined. In this report we provide a formal definition of the specialization relationship at the level of i* SR diagrams. We root our proposal over existing work in conceptual modeling in general, and object-orientation in particular. Also, we use the results of a survey conducted in the i* community that provides some hints about what i* modelers expect from specialization. As a consequence of this twofold analysis, we identify, define and specify two specialization operations, extension and refinement, that can be applied over SR diagrams. Correctness conditions for them are also clearly stated. The result of our work is a formal proposal of specialization for i* that allows its use in a well-defined manner. Wed, 10 Oct 2012 15:23:35 GMT http://hdl.handle.net/2117/16708 2012-10-10T15:23:35Z López Cuesta, Lidia; Franch Gutiérrez, Javier; Marco Gómez, Jordi no The specialization relationship is offered by the i* modeling language through the is-a construct defined over actors (a subactor is-a superactor). Although the overall meaning of this construct is highly intuitive, its semantics of strategic rationale (SR) diagrams is not defined. In this report we provide a formal definition of the specialization relationship at the level of i* SR diagrams. We root our proposal over existing work in conceptual modeling in general, and object-orientation in particular. Also, we use the results of a survey conducted in the i* community that provides some hints about what i* modelers expect from specialization. As a consequence of this twofold analysis, we identify, define and specify two specialization operations, extension and refinement, that can be applied over SR diagrams. Correctness conditions for them are also clearly stated. The result of our work is a formal proposal of specialization for i* that allows its use in a well-defined manner. http://hdl.handle.net/2117/15716 Title: Non-functional requirements in software architecture practice Authors: Ameller, David; Ayala Martínez, Claudia Patricia; Cabot Sagrera, Jordi; Franch Gutiérrez, Javier Abstract: Dealing with non-functional requirements (NFRs) has posed a challenge onto software engineers for many years. Over the years, many methods and techniques have been proposed to improve their elicitation, documentation, and validation. Knowing more about the state of the practice on these topics may benefit both practitioners’ and researchers’ daily work. A few empirical studies have been conducted in the past, but none under the perspective of software architects, in spite of the great influence that NFRs have on daily architects’ practices. This paper presents some of the findings of an empirical study based on 13 interviews with software architects. It addresses questions such as: who decides the NFRs, what types of NFRs matter to architects, how are NFRs documented, and how are NFRs validated. The results are contextualized with existing previous work. Tue, 10 Apr 2012 11:50:02 GMT http://hdl.handle.net/2117/15716 2012-04-10T11:50:02Z Ameller, David; Ayala Martínez, Claudia Patricia; Cabot Sagrera, Jordi; Franch Gutiérrez, Javier no Dealing with non-functional requirements (NFRs) has posed a challenge onto software engineers for many years. Over the years, many methods and techniques have been proposed to improve their elicitation, documentation, and validation. Knowing more about the state of the practice on these topics may benefit both practitioners’ and researchers’ daily work. A few empirical studies have been conducted in the past, but none under the perspective of software architects, in spite of the great influence that NFRs have on daily architects’ practices. This paper presents some of the findings of an empirical study based on 13 interviews with software architects. It addresses questions such as: who decides the NFRs, what types of NFRs matter to architects, how are NFRs documented, and how are NFRs validated. The results are contextualized with existing previous work. http://hdl.handle.net/2117/14848 Title: WeSSQoS: a configurable SOA system for quality-aware web service selection Authors: Cabrera Bejar, Oscar; Oriol Hilari, Marc; Franch Gutiérrez, Javier; López Cuesta, Lidia; Marco Gómez, Jordi; Fragoso, Olivia; Santaolaya, René Abstract: Web Services (WS) have become one the most used technologies nowadays in software systems. Among the challenges when integrating WS in a given system, requirements-driven selection occupies a prominent place. A comprehensive selection process needs to check compliance of Non-Functional Requirements (NFR), which can be assessed by analysing WS Quality of Service (QoS). In this paper, we describe the WeSSQoS system that aims at ranking available WS based on the comparison of their QoS and the stated NFRs. WeSSQoS is designed as an open service-oriented architecture that hosts a configurable portfolio of normalization and ranking algorithms that can be selected by the engineer when starting a selection process. WS’ QoS can be obtained either from a static, WSDL-like description, or computed dynamically through monitoring techniques. WeSSQoS is designed to work over multiple WS repositories and QoS sources. The impact of having a portfolio of different normalization and ranking algorithms is illustrated with an example. Fri, 27 Jan 2012 12:08:36 GMT http://hdl.handle.net/2117/14848 2012-01-27T12:08:36Z Cabrera Bejar, Oscar; Oriol Hilari, Marc; Franch Gutiérrez, Javier; López Cuesta, Lidia; Marco Gómez, Jordi; Fragoso, Olivia; Santaolaya, René no Web Services (WS) have become one the most used technologies nowadays in software systems. Among the challenges when integrating WS in a given system, requirements-driven selection occupies a prominent place. A comprehensive selection process needs to check compliance of Non-Functional Requirements (NFR), which can be assessed by analysing WS Quality of Service (QoS). In this paper, we describe the WeSSQoS system that aims at ranking available WS based on the comparison of their QoS and the stated NFRs. WeSSQoS is designed as an open service-oriented architecture that hosts a configurable portfolio of normalization and ranking algorithms that can be selected by the engineer when starting a selection process. WS’ QoS can be obtained either from a static, WSDL-like description, or computed dynamically through monitoring techniques. WeSSQoS is designed to work over multiple WS repositories and QoS sources. The impact of having a portfolio of different normalization and ranking algorithms is illustrated with an example. http://hdl.handle.net/2117/13059 Title: A unifying framework for the definition of syntactic measures over conceptual schema diagrams (extended version) Authors: Costal Costa, Dolors; Franch Gutiérrez, Javier Abstract: There are many approaches that propose the use of measures for assessing the quality of conceptual schemas. Many of these measures focus purely on the syntactic aspects of the conceptual schema diagrams, e.g. their size, their shape, etc. Similarities among different measures may be found both at the intra-model level (i.e., several measures over the same type of diagram are defined following the same layout) and at the inter-model level (i.e., measures over different types of diagrams are similar considering an appropriate metaschema correspondence). In this paper we analyse these similarities for a particular family of diagrams used in conceptual modelling, those that can be ultimately seen as a combination of nodes and edges of different types. We propose a unifying measuring framework for this family and illustrate its application on a particular type, namely business process diagrams. Wed, 27 Jul 2011 09:29:48 GMT http://hdl.handle.net/2117/13059 2011-07-27T09:29:48Z Costal Costa, Dolors; Franch Gutiérrez, Javier no Conceptual schema measure, Conceptual schema diagram, Metamodelling, MOF There are many approaches that propose the use of measures for assessing the quality of conceptual schemas. Many of these measures focus purely on the syntactic aspects of the conceptual schema diagrams, e.g. their size, their shape, etc. Similarities among different measures may be found both at the intra-model level (i.e., several measures over the same type of diagram are defined following the same layout) and at the inter-model level (i.e., measures over different types of diagrams are similar considering an appropriate metaschema correspondence). In this paper we analyse these similarities for a particular family of diagrams used in conceptual modelling, those that can be ultimately seen as a combination of nodes and edges of different types. We propose a unifying measuring framework for this family and illustrate its application on a particular type, namely business process diagrams. http://hdl.handle.net/2117/12827 Title: On the meanings of subsetting, specialization and redefinition in UML Authors: Costal Costa, Dolors; Gómez Seoane, Cristina; Guizzardi, Giancarlo Abstract: UML 2 has improved the expressiveness of the language with respect to associations in several manners. A significant one has been the introduction of the association redefinition concept. Association subsetting and association specialization have been included in UML since its earliest versions and share some relevant features with association redefinition. These similarities among the three constructs make it frequently difficult, especially to novice users, to: decide which one of these concepts is the best suited to model a particular situation; systematically justify their modelling choices. In this report, we present a preliminary empirical investigation on these constructs using as a benchmark a catalogue of model examples produced by different authors which can be considered experts in the conceptual modelling field. Tue, 28 Jun 2011 07:27:31 GMT http://hdl.handle.net/2117/12827 2011-06-28T07:27:31Z Costal Costa, Dolors; Gómez Seoane, Cristina; Guizzardi, Giancarlo no UML 2 has improved the expressiveness of the language with respect to associations in several manners. A significant one has been the introduction of the association redefinition concept. Association subsetting and association specialization have been included in UML since its earliest versions and share some relevant features with association redefinition. These similarities among the three constructs make it frequently difficult, especially to novice users, to: decide which one of these concepts is the best suited to model a particular situation; systematically justify their modelling choices. In this report, we present a preliminary empirical investigation on these constructs using as a benchmark a catalogue of model examples produced by different authors which can be considered experts in the conceptual modelling field. http://hdl.handle.net/2117/12369 Title: Development of the conceptual schema of the osTicket system by applying TDCM Authors: Tort Pugibet, Albert Abstract: This document reports a case study application of Test-Driven Conceptual Modeling (TDCM) in the reverse engineering development of the conceptual schema of a well-known, open-source and widely-used online support system called osTicket. Thu, 14 Apr 2011 14:53:50 GMT http://hdl.handle.net/2117/12369 2011-04-14T14:53:50Z Tort Pugibet, Albert no This document reports a case study application of Test-Driven Conceptual Modeling (TDCM) in the reverse engineering development of the conceptual schema of a well-known, open-source and widely-used online support system called osTicket. http://hdl.handle.net/2117/11196 Title: Development of the conceptual schema of a bowling game system by applying TDCM Authors: Tort Pugibet, Albert Abstract: We report a case study application of Test-Driven Conceptual Modeling (TDCM) in the development of the conceptual schema of a bowling game system, which has been used in the literature to describe in practice the use of Test-Driven Development (TDD) in the programming field. Tue, 25 Jan 2011 12:27:47 GMT http://hdl.handle.net/2117/11196 2011-01-25T12:27:47Z Tort Pugibet, Albert no We report a case study application of Test-Driven Conceptual Modeling (TDCM) in the development of the conceptual schema of a bowling game system, which has been used in the literature to describe in practice the use of Test-Driven Development (TDD) in the programming field. http://hdl.handle.net/2117/9991 Title: GEM: requirement-driven generation of ETL and multidimensional conceptual designs Authors: Romero Moral, Óscar; Simitsis, Alkis; Abelló Gamazo, Alberto Abstract: At the early stages of a data warehouse design project, the main objective is to collect the business requirements and needs, and translate them into an appropriate conceptual, multidimensional design. Typically, this task is performed manually, through a series of interviews involving two different parties: the business analysts and technical designers. Producing an appropriate conceptual design is an errorprone task that undergoes several rounds of reconciliation and redesigning, until the business needs are satisfied. It is of great importance for the business of an enterprise to facilitate and automate such a process. The goal of our research is to provide designers with a semi-automatic means for producing conceptual multidimensional designs and also, conceptual representation of the extract-transform-load (ETL)processes that orchestrate the data flow from the operational sources to the data warehouse constructs. In particular, we describe a method that combines information about the data sources along with the business requirements, for validating and completing –if necessary– these requirements, producing a multidimensional design, and identifying the ETL operations needed. We present our method in terms of the TPC-DS benchmark and show its applicability and usefulness. Description: Technical Report Tue, 26 Oct 2010 10:16:24 GMT http://hdl.handle.net/2117/9991 2010-10-26T10:16:24Z Romero Moral, Óscar; Simitsis, Alkis; Abelló Gamazo, Alberto no DW, ETL, Multidimensional design, Conceptual Design At the early stages of a data warehouse design project, the main objective is to collect the business requirements and needs, and translate them into an appropriate conceptual, multidimensional design. Typically, this task is performed manually, through a series of interviews involving two different parties: the business analysts and technical designers. Producing an appropriate conceptual design is an errorprone task that undergoes several rounds of reconciliation and redesigning, until the business needs are satisfied. It is of great importance for the business of an enterprise to facilitate and automate such a process. The goal of our research is to provide designers with a semi-automatic means for producing conceptual multidimensional designs and also, conceptual representation of the extract-transform-load (ETL)processes that orchestrate the data flow from the operational sources to the data warehouse constructs. In particular, we describe a method that combines information about the data sources along with the business requirements, for validating and completing –if necessary– these requirements, producing a multidimensional design, and identifying the ETL operations needed. We present our method in terms of the TPC-DS benchmark and show its applicability and usefulness. http://hdl.handle.net/2117/9652 Title: On the semantics of redefinition, specialization and subsetting of associations in UML (extended version) Authors: Costal Costa, Dolors; Gómez Seoane, Cristina; Nieto Soler, Pilar Abstract: The definition of the exact meaning of conceptual modeling concepts is considered a relevant issue since it enhances their effective and appropriate use by designers and facilitates the automatic processing of the models where they are included. Three related concepts that permit to improve the definition of an association in UML and which still lack of a formal semantic definition are: association redefinition, association specialization and association subsetting. This paper formalizes their semantics and points out the similarities and differences that exist among them. The formalization we propose is based on the meta-modelling approach and a semantic domain composed of a set of basic UML concepts and OCL expressions, which have a previous formal definition in the literature and which are well-understood. Wed, 13 Oct 2010 09:02:24 GMT http://hdl.handle.net/2117/9652 2010-10-13T09:02:24Z Costal Costa, Dolors; Gómez Seoane, Cristina; Nieto Soler, Pilar no Association redefinition, Association specialization, Association subsetting, Unified Modelling Language The definition of the exact meaning of conceptual modeling concepts is considered a relevant issue since it enhances their effective and appropriate use by designers and facilitates the automatic processing of the models where they are included. Three related concepts that permit to improve the definition of an association in UML and which still lack of a formal semantic definition are: association redefinition, association specialization and association subsetting. This paper formalizes their semantics and points out the similarities and differences that exist among them. The formalization we propose is based on the meta-modelling approach and a semantic domain composed of a set of basic UML concepts and OCL expressions, which have a previous formal definition in the literature and which are well-understood. http://hdl.handle.net/2117/7563 Title: Dealing with non-functional requirements in model-driven development Authors: Ameller, David; Franch Gutiérrez, Javier; Cabot Sagrera, Jordi Abstract: The impact of non-functional requirements (NFRs) over software systems has been widely documented. Consequently, cost-effective software production method shall provide means to integrate this type of requirements into the development process. In this vision paper we analyze this assumption over a particular type of software production paradigm: model-driven development (MDD). We report first the current state of MDD approaches with respect to NFRs and remark that, in general, NFRs are not addressed in MDD methods and processes, and we discuss the effects of this situation. Next, we outline a general framework that integrates NFRs into the core of the MDD process and provide a detailed comparison among all the MDD approaches considered. Last, we identify some research issues related to this framework. Tue, 08 Jun 2010 10:38:53 GMT http://hdl.handle.net/2117/7563 2010-06-08T10:38:53Z Ameller, David; Franch Gutiérrez, Javier; Cabot Sagrera, Jordi no The impact of non-functional requirements (NFRs) over software systems has been widely documented. Consequently, cost-effective software production method shall provide means to integrate this type of requirements into the development process. In this vision paper we analyze this assumption over a particular type of software production paradigm: model-driven development (MDD). We report first the current state of MDD approaches with respect to NFRs and remark that, in general, NFRs are not addressed in MDD methods and processes, and we discuss the effects of this situation. Next, we outline a general framework that integrates NFRs into the core of the MDD process and provide a detailed comparison among all the MDD approaches considered. Last, we identify some research issues related to this framework.