20,682 research outputs found

    Evaluation of e-learning web sites using fuzzy axiomatic design based approach

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    High quality web site has been generally recognized as a critical enabler to conduct online business. Numerous studies exist in the literature to measure the business performance in relation to web site quality. In this paper, an axiomatic design based approach for fuzzy group decision making is adopted to evaluate the quality of e-learning web sites. Another multi-criteria decision making technique, namely fuzzy TOPSIS, is applied in order to validate the outcome. The methodology proposed in this paper has the advantage of incorporating requirements and enabling reductions in the problem size, as compared to fuzzy TOPSIS. A case study focusing on Turkish e-learning websites is presented, and based on the empirical findings, managerial implications and recommendations for future research are offered

    Modeling the Structure and Complexity of Engineering Routine Design Problems

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    This paper proposes a model to structure routine design problems as well as a model of its design complexity. The idea is that having a proper model of the structure of such problems enables understanding its complexity, and likewise, a proper understanding of its complexity enables the development of systematic approaches to solve them. The end goal is to develop computer systems capable of taking over routine design tasks based on generic and systematic solving approaches. It is proposed to structure routine design in three main states: problem class, problem instance, and problem solution. Design complexity is related to the degree of uncertainty in knowing how to move a design problem from one state to another. Axiomatic Design Theory is used as reference for understanding complexity in routine design

    Aircraft systems architecting: a functional-logical domain perspective

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    Presented is a novel framework for early systems architecture design. The framework defines data structures and algorithms that enable the systems architect to operate interactively and simultaneously in both the functional and logical domains. A prototype software tool, called AirCADia Architect, was implemented, which allowed the framework to be evaluated by practicing aircraft systems architects. The evaluation confirmed that, on the whole, the approach enables the architects to effectively express their creative ideas when synthesizing new architectures while still retaining control over the process

    Complexity in Designing Energy Efficient Buildings: Towards Understanding Decision Networks in Design

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    Most important decisions for designing energy efficient buildings are made in the early stages of design. Designing is a complex interdisciplinary task, and energy efficiency requirements are pushing boundaries even further. This study analyzes the level of complexity for energy efficient building design and possible remedies for managing or reducing the complexity. Methodologically, we used the design structure matrix for mapping the current design tasks and hierarchical decomposition of lifecycle analysis for visualizing the interdependency of the design tasks and design disciplines and how changes propagate throughout the system, tasks and disciplines. We have visualized the interdependency of design tasks and design disciplines and how changes propagate throughout the system. Current design of energy efficiency building is a linear and one-shot approach without iterations planned into the process. Broken management techniques do not help to reduce the complexit

    Kajian keberkesanan olahan larut lesapan menggunakan elektrod aluminum dan ferum dalam sistem elektro-penggumpalan

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    Elektro-pengumpalan merupakan satu kaedah alternatif yang kompetatif selain daripada kaedah konvesional bagi merawat air sisa terutamanya larut lesapan yang mempunyai struktur bahan pencemar yang kompleks dan tinggi. Kajian keberkesanan elekto-penggumpalan telahpun dijalankan bagi menentukan keberkesanan sistem ini beroperasi. Objektif utama kajian ini adalah bagi mengkaji keberkesanan dan potensi sistem beroperasi dengan menggunakan empat jenis susunan elektrod, Fe-Fe, Al-Al, Fe dan aluminum sulfat di samping penentuan nilai optimum ketumpatan arus elektrik, jarak antara elektrod, masa tindakbalas, pH, masa enapan dan aluminum sulfat. Penggunaan CILAS Analyzer digunakan bagi menentukan saiz flok di setiap penentuan optimum yang diperolehi. Sebanyak 750 liter sampel larut lesapan diambil pada awal bulan Disember 2010 - Januari 2011. Pengujian awalan BOD, COD, pepejal terampai, nitrogen ammonia, warna dan kekeruhan turut diuji terhadap sampel mentah yang diperolehi. Reaktor kaca bersaiz 300mm x 80mm x 200mm (4 L sampel) dengan luas berkesan elektrod penggumpal, 60 sm + - + - -Al , Al -Fe 2 digunakan di samping ujian penyingkiran parameter seperti COD, pepejal terampai, nitrogen ammonia warna dan kekeruhan turut diuji di dalam kajian ini. Hasil keseluruhan kajian mendapati bahawa penggunaan elektrod Al-Al memberikan peratus penyingkiran tertinggi di mana penentuan optimum yang diperolehi bagi ketumpatan arus elektrik adalah 0.025 amp/sm , jarak antara elektrod, 10 cm, masa tindakbalas, 60 minit, pH 5 dan masa enapan, 30 minit. Peratus penyingkiran yang diperolehi bagi COD, pepejal terampai, nitrogen ammonia, warna dan kekeruhan adalah 82.5%, 94.7%, 65.6%, 91% and 90.6%. Percampuran aluminum sulfat terhadap penggunaan elektrod Al-Al memberikan dos optimum sebanyak 1500 mg/l di mana penyingkiran tertinggi yang diperolehi bagi COD, pepejal terampai, nitrogen ammonia, warna dan kekeruhan adalah 84.2%, 81%, 80.3%, 75% and 81.1%. Kesimpulanya, penggunaan elektrod Al-Al dicadangkan, di mana sedikit pra olahan perlu dilakukan bagi menepati piawaian yang dibenarkan oleh Standard Malaysia bagi tahap lepasan larut lesapan. Katakunci: air sisa domestik; Elektro-pengumpalan; larut lesapa

    A Process Modelling Framework Based on Point Interval Temporal Logic with an Application to Modelling Patient Flows

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    This thesis considers an application of a temporal theory to describe and model the patient journey in the hospital accident and emergency (A&E) department. The aim is to introduce a generic but dynamic method applied to any setting, including healthcare. Constructing a consistent process model can be instrumental in streamlining healthcare issues. Current process modelling techniques used in healthcare such as flowcharts, unified modelling language activity diagram (UML AD), and business process modelling notation (BPMN) are intuitive and imprecise. They cannot fully capture the complexities of the types of activities and the full extent of temporal constraints to an extent where one could reason about the flows. Formal approaches such as Petri have also been reviewed to investigate their applicability to the healthcare domain to model processes. Additionally, to schedule patient flows, current modelling standards do not offer any formal mechanism, so healthcare relies on critical path method (CPM) and program evaluation review technique (PERT), that also have limitations, i.e. finish-start barrier. It is imperative to specify the temporal constraints between the start and/or end of a process, e.g., the beginning of a process A precedes the start (or end) of a process B. However, these approaches failed to provide us with a mechanism for handling these temporal situations. If provided, a formal representation can assist in effective knowledge representation and quality enhancement concerning a process. Also, it would help in uncovering complexities of a system and assist in modelling it in a consistent way which is not possible with the existing modelling techniques. The above issues are addressed in this thesis by proposing a framework that would provide a knowledge base to model patient flows for accurate representation based on point interval temporal logic (PITL) that treats point and interval as primitives. These objects would constitute the knowledge base for the formal description of a system. With the aid of the inference mechanism of the temporal theory presented here, exhaustive temporal constraints derived from the proposed axiomatic system’ components serves as a knowledge base. The proposed methodological framework would adopt a model-theoretic approach in which a theory is developed and considered as a model while the corresponding instance is considered as its application. Using this approach would assist in identifying core components of the system and their precise operation representing a real-life domain deemed suitable to the process modelling issues specified in this thesis. Thus, I have evaluated the modelling standards for their most-used terminologies and constructs to identify their key components. It will also assist in the generalisation of the critical terms (of process modelling standards) based on their ontology. A set of generalised terms proposed would serve as an enumeration of the theory and subsume the core modelling elements of the process modelling standards. The catalogue presents a knowledge base for the business and healthcare domains, and its components are formally defined (semantics). Furthermore, a resolution theorem-proof is used to show the structural features of the theory (model) to establish it is sound and complete. After establishing that the theory is sound and complete, the next step is to provide the instantiation of the theory. This is achieved by mapping the core components of the theory to their corresponding instances. Additionally, a formal graphical tool termed as point graph (PG) is used to visualise the cases of the proposed axiomatic system. PG facilitates in modelling, and scheduling patient flows and enables analysing existing models for possible inaccuracies and inconsistencies supported by a reasoning mechanism based on PITL. Following that, a transformation is developed to map the core modelling components of the standards into the extended PG (PG*) based on the semantics presented by the axiomatic system. A real-life case (from the King’s College hospital accident and emergency (A&E) department’s trauma patient pathway) is considered to validate the framework. It is divided into three patient flows to depict the journey of a patient with significant trauma, arriving at A&E, undergoing a procedure and subsequently discharged. Their staff relied upon the UML-AD and BPMN to model the patient flows. An evaluation of their representation is presented to show the shortfalls of the modelling standards to model patient flows. The last step is to model these patient flows using the developed approach, which is supported by enhanced reasoning and scheduling

    Design for validation: An approach to systems validation

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    Every complex system built is validated in some manner. Computer validation begins with review of the system design. As systems became too complicated for one person to review, validation began to rely on the application of adhoc methods by many individuals. As the cost of the changes mounted and the expense of failure increased, more organized procedures became essential. Attempts at devising and carrying out those procedures showed that validation is indeed a difficult technical problem. The successful transformation of the validation process into a systematic series of formally sound, integrated steps is necessary if the liability inherent in the future digita-system-based avionic and space systems is to be minimized. A suggested framework and timetable for the transformtion are presented. Basic working definitions of two pivotal ideas (validation and system life-cyle) are provided and show how the two concepts interact. Many examples are given of past and present validation activities by NASA and others. A conceptual framework is presented for the validation process. Finally, important areas are listed for ongoing development of the validation process at NASA Langley Research Center

    A QFD framework for quality, innovation and high-tech product development dynamics

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    The customer mostly chooses a product on the base of its quality, which therefore arises as the main cause of its commercial success. In a nearly axiomatic drawing, it follows that the effect of innovation is the improvement of quality, which itself becomes the aim of innovation. Even though the previous statement relates quality and innovation, it still does not explain their dynamics. To stress them, the ‘quality' concept must be analyzed in more detail. In fact, in addition to the ‘perceived quality', the quality ensured through `design, manufacturing and marketing' combined domains should be dealt with. This paper enhances this issue taking advantage of principles and models made available by control theory schemes coupled with quality function development (QFD) and best practice software modeling based on unified modeling language (UML
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