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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Måste det alltid bråkas med bråk? : En systematisk litteraturstudie om stambråkets betydelse i matematikundervisningen

Nordliden, Petter, Didrik Sjöbladh, Linda January 2020 (has links)
Denna systematiska litteraturstudie syftar till att med hjälp av forskning identifiera avgörande faktorer för framgångsrika undervisningsstrategier av stambråk i grundskolans matematikundervisning. Studien baseras på elva vetenskapliga artiklar som bearbetats systematiskt med hjälp av innehållsanalys för att besvara forsknings-frågorna om vilka avgörande faktorer som forskningen visar för undervisningen av stambråk samt vilka framgångsrika undervisningsstrategier som finns. Forskningen visar att areamodellen som representationsform dominerar undervisningen av bråk vilket innebär att stambråk får lite plats i undervisningen. Stambråket är en viktig del för att kunna tillägna sig avgörande faktorer av bråk. Resultatet visar att en undervisning med linear measurement (linjära representationsformer) betonar stambråkets roll som tolkningsverktyg för att kunna jämföra andra bråk samt det omvända förhållandet där en större nämnare utgör en mindre andel. Resultatet visar också att undervisningen av stambråk etablerar grundläggande principer för rationella tal och mer avancerade matematiska områden som proportionalitet och algebra. Därmed är lärares val av undervisningsstrategier och representationsformer samt deras kunskaper inom dessa områden vitala för vad eleverna kan tillägna sig i samband med bråkundervisningen.
442

Hur skapas värde inom ett hållbart tjänsteekosystem? : En kvalitativ studie utifrån ett tjänstedominant perspektiv / How is value created within a sustainable service ecosystem? : A qualitative study from a service dominant perspective

Eriksson, Simon, Sandberg, Robin January 2021 (has links)
Samtidigt som fokuset på hållbarhetsarbete inom organisationer har ökat, har det även resulterat i frågor om hur företag skapar ett hållbart värde. Hållbarhet har definierats utifrån tre grundpelare: miljömässig-, ekonomisk- och socialhållbarhet. Inom tjänsteteori har intresset för hållbarhetsteorier ökat, men relationen mellan dessa områden är relativt outforskade. Detta är förvånansvärt då många organisationer är beroende av hållbart värdeskapande. Således är syftet med studien att alstra förståelse för hur aktörer skapar värden inom ett hållbart tjänsteekosystem. Studien utgår från ett makroperspektiv eftersom viktiga implikationer för värdeskapande kan upptäckas då hållbarhet genererar värde för flera aktörer. Det teoretiska ramverket omfattar tre delar; teori om tjänsteekosystem, hållbarhet och en sammanföring mellan dessa områden. Eftersom värdeskapande inom hållbara tjänsteekosystem är relativt outforskat valdes en kvalitativ och explorativ ansats för att undersöka hur hållbart arbete inom ett tjänsteekosystem bidrar till att skapa värde.  Analysen förankras i nio semistrukturerade intervjuer som genomfördes med respondenter från olika organisationer som tillhörde företagsklustret Paper Province. Intervjuerna kombineras med teori för att skapa en koppling mellan ett empiriskt fall och teori. Deltagande respondenter hade hög befattning inom respektive organisation, vilket var viktigt för att förstå organisationens struktur. Studien visar att hållbarhet inte bara ligger till grund för organisationers värdeskapande logik utan även skapar en grund för arbetsstrukturer. Genom att utgå från tjänstedominant logik ger analysen ett nytt sätt att se på hållbara aktörers värdeskapande. Inom det hållbara tjänsteekosystemet skapar aktörer förutsättningar för ett högre samhällsvärde till följd av hållbar resursintegration. / At the same time as the focus on sustainability work within organizations has increased, it has also resulted in questions about how companies create sustainable value. Sustainability has been defined based on three pillars: environmental, economic, and social sustainability. In service theory, interest in sustainability theories has increased, but the relationship between these areas is relatively unexplored. This is surprising as many organizations are dependent on sustainable value creation. Thus, the study aims to generate an understanding of how actors create value within a sustainable service ecosystem. The study is based on a macro perspective because important implications for value creation can be discovered as sustainability generates value for several actors. The theoretical framework comprises three parts; theory of service ecosystems, sustainability, and a merger between these areas. Since value creation in sustainable service ecosystems is relatively unexplored, a qualitative and exploratory approach was chosen to investigate how sustainable work in a service ecosystem contributes to creating value.  The analysis is anchored in nine semi-structured interviews conducted with respondents from various organizations that belonged to the Paper Province cluster. The interviews are combined with theory to create a connection between an empirical case and theory. Participating respondents held senior positions within each organization, which was important for understanding the organization's structure. The study shows that sustainability forms the basis for organizations' value-creating logic and creates a basis for work structures. Based on service-dominant logic, the analysis provides a new way of looking at sustainable players' value creation. Within the sustainable service ecosystem, actors create conditions for a higher societal value because of sustainable resource integration.
443

Developing decision-support tools for evaluation of manufacturing reshoring decisions

Sequeira, Movin January 2020 (has links)
During last three decades, companies have offshored their manufacturing activities across international borders in order to pursue lower manufacturing costs. Despite having accomplished their purpose, companies have also suffered from issues, especially poor quality of products and a poor response to customer demand. Therefore, companies consider relocating some of the manufacturing activities back to the home country, a process that is known as manufacturing reshoring. There is paucity of scholarly attention on how manufacturing reshoring decisions are evaluated and supported. Therefore, the purpose of this thesis is to develop decision-support tools to evaluate manufacturing reshoring decisions. In order to fulfil this, it is important to know how industry experts reason while making manufacturing reshoring decisions (RQ1), and how their reasoning can be modeled into decision-support tools (RQ2). Therefore, three studies were conducted including a multiple case study and two modeling studies. The multiple case study addressed the criteria that are considered by the industry experts in these decisions, while the two modeling studies, based on fuzzy logic and analytical hierarchy process (AHP), used a part of these criteria to develop decision-support tools. The findings indicate that a holistic set of criteria were considered by industry experts in arriving at a manufacturing reshoring decision. A large portion of these criteria occur within competitive priority category and among them, high importance is given to quality, while low importance to sustainability. Fuzzy logic modeling was used to model the criteria from the perspective of competitive priority at an overall level. Three fuzzy logic concepts were developed to capture industry experts’ reasoning and facilitate modeling of manufacturing reshoring decisions. Furthermore, two configurations and sixteen settings were developed, of which, the best ones were identified. AHP-based tools were used to capture experts’ reasoning of the competitive priority criteria by comparing the criteria. It was observed that fuzzy logic-based tools are able to better emulate industry experts’ reasoning of manufacturing reshoring. This research contributes to theory with a holistic framework of reshoring decision criteria, and to practice with decision-support tools for evaluation of manufacturing reshoring decisions. / Under de tre senaste decennierna har många företag flyttat sin produktion till lågkostnadsländer för att kunna utnyttja lägre lönekostnader. Många gånger har företagen genom denna åtgärd lyckats sänka sin tillverkningskostnad men samtidigt drabbats av oförutsedda problem kopplat till exempelvis produkt-kvalitet och möjligheten att kundanpassa produkter. Hanteringen av problemen har lett till ytterligare kostnader som många gånger överstigit besparingen i tillverkningskostnad. Detta har lett till att allt fler företag börjat flytta tillbaka sin produktion till hemlandet, så kallad reshoring. Reshoring är ett ungt område där det saknas forskning gällande bland annat hur den här typen av beslut på bästa sätt kan utvärderas och vilken typ av beslutstöd som kan underlätta den här typen av beslut. Därför är syftet med den här avhandlingen är att utveckla beslutsstödverktyg för utvärdering av reshoring beslut. För att uppfylla syftet har två forskningsfrågor formulerats. Den första frågan handlar om hur industriexperter resonerar kring reshoring beslut (RQ1) medan den andra frågan handlar om hur deras resonemang kan modelleras i beslutsstödverktyg (RQ2). Tre studier har genomförts för att besvara forskningsfrågorna, en fallstudie och två modelleringsstudier. Fallstudien fokuserar på att identifiera vilka kriterier som industriexperter beaktar medan modelleringsstudierna fokuserar på att utveckla beslutstödsverktyg där en del av dessa kriterier beaktas, med hjälp av fuzzy logic och analytical hierarchy process (AHP). Resultaten från forskningen visar att industriexperter bedömer reshoring beslut utifrån ett holistiskt perspektiv. En stor del av dessa beslutskriterier finns inom konkurrenskraft kategorin och inom dessa, har industriexperterna lagt högst vikt på kvalitet och lägst vikt på hållbarhet. Genom fuzzy logic modellering modellerades kriterierna på en övergripande nivå. Tre nya fuzzy logic koncept utvecklades för att fånga experternas resonemang. Dessutom utvecklades två konfigurationer med sexton olika inställningar, och de bästa identifierades. AHP-baserade verktyg utvecklades för att fånga experternas resonemang om kriterierna för konkurrenskraft prioriteringar. Fuzzy logic-baserade verktyg kan bättre fånga experternas resonemang kring reshoring beslut. Denna forskning bidrar till teori med en holistisk lista över beslutskriterier för reshoring beslut, och till praktik med beslutsstöd verktyg för utvärdering av reshoring beslut.
444

A Gröbner basis algorithm for fast encoding of Reed-Müller codes

Abrahamsson, Olle January 2016 (has links)
In this thesis the relationship between Gröbner bases and algebraic coding theory is investigated, and especially applications towards linear codes, with Reed-Müller codes as an illustrative example. We prove that each linear code can be described as a binomial ideal of a polynomial ring, and that a systematic encoding algorithm for such codes is given by the remainder of the information word computed with respect to the reduced Gröbner basis. Finally we show how to apply the representation of a code by its corresponding polynomial ring ideal to construct a class of codes containing the so called primitive Reed-Müller codes, with a few examples of this result.
445

Probabilistic Logic, Probabilistic Regular Expressions, and Constraint Temporal Logic

Weidner, Thomas 21 June 2016 (has links)
The classic theorems of Büchi and Kleene state the expressive equivalence of finite automata to monadic second order logic and regular expressions, respectively. These fundamental results enjoy applications in nearly every field of theoretical computer science. Around the same time as Büchi and Kleene, Rabin investigated probabilistic finite automata. This equally well established model has applications ranging from natural language processing to probabilistic model checking. Here, we give probabilistic extensions Büchi\\\''s theorem and Kleene\\\''s theorem to the probabilistic setting. We obtain a probabilistic MSO logic by adding an expected second order quantifier. In the scope of this quantifier, membership is determined by a Bernoulli process. This approach turns out to be universal and is applicable for finite and infinite words as well as for finite trees. In order to prove the expressive equivalence of this probabilistic MSO logic to probabilistic automata, we show a Nivat-theorem, which decomposes a recognisable function into a regular language, homomorphisms, and a probability measure. For regular expressions, we build upon existing work to obtain probabilistic regular expressions on finite and infinite words. We show the expressive equivalence between these expressions and probabilistic Muller-automata. To handle Muller-acceptance conditions, we give a new construction from probabilistic regular expressions to Muller-automata. Concerning finite trees, we define probabilistic regular tree expressions using a new iteration operator, called infinity-iteration. Again, we show that these expressions are expressively equivalent to probabilistic tree automata. On a second track of our research we investigate Constraint LTL over multidimensional data words with data values from the infinite tree. Such LTL formulas are evaluated over infinite words, where every position possesses several data values from the infinite tree. Within Constraint LTL on can compare these values from different positions. We show that the model checking problem for this logic is PSPACE-complete via investigating the emptiness problem of Constraint Büchi automata.
446

The Expressive Power, Satisfiability and Path Checking Problems of MTL and TPTL over Non-Monotonic Data Words

Feng, Shiguang 19 April 2016 (has links)
Recently, verification and analysis of data words have gained a lot of interest. Metric temporal logic (MTL) and timed propositional temporal logic (TPTL) are two extensions of Linear time temporal logic (LTL). In MTL, the temporal operator are indexed by a constraint interval. TPTL is a more powerful logic that is equipped with a freeze formalism. It uses register variables, which can be set to the current data value and later these register variables can be compared with the current data value. For monotonic data words, Alur and Henzinger proved that MTL and TPTL are equally expressive and the satisfiability problem is decidable. We study the expressive power, satisfiability problems and path checking problems for MLT and TPTL over all data words. We introduce Ehrenfeucht-Fraisse games for MTL and TPTL. Using the EF-game for MTL, we show that TPTL is strictly more expressive than MTL. Furthermore, we show that the MTL definability problem that whether a TPTL-formula is definable in MTL is not decidable. When restricting the number of register variables, we are able to show that TPTL with two register variables is strictly more expressive than TPTL with one register variable. For the satisfiability problem, we show that for MTL, the unary fragment of MTL and the pure fragment of MTL, SAT is not decidable. We prove the undecidability by reductions from the recurrent state problem and halting problem of two-counter machines. For the positive fragments of MTL and TPTL, we show that a positive formula is satisfiable if and only it is satisfied by a finite data word. Finitary SAT and infinitary SAT coincide for positive MTL and positive TPTL. Both of them are r.e.-complete. For existential TPTL and existential MTL, we show that SAT is NP-complete. We also investigate the complexity of path checking problems for TPTL and MTL over data words. These data words can be either finite or infinite periodic. For periodic words without data values, the complexity of LTL model checking belongs to the class AC^1(LogDCFL). For finite monotonic data words, the same complexity bound has been shown for MTL by Bundala and Ouaknine. We show that path checking for TPTL is PSPACE-complete, and for MTL is P-complete. If the number of register variables allowed is restricted, we obtain path checking for TPTL with only one register variable is P-complete over both infinite and finite data words; for TPTL with two register variables is PSPACE-complete over infinite data words. If the encoding of constraint numbers of the input TPTL-formula is in unary notation, we show that path checking for TPTL with a constant number of variables is P-complete over infinite unary encoded data words. Since the infinite data word produced by a deterministic one-counter machine is periodic, we can transfer all complexity results for the infinite periodic case to model checking over deterministic one-counter machines.
447

Position and potential of service-dominant logic

Löbler, Helge 02 February 2017 (has links)
This work offers a framework for researchers by linking service-dominant (S-D) logic to an intersubjective stream of philosophy of science. Service-dominant logic has resonated in marketing, but no existing research has attempted to link S-D logic with basic meta-theory to provide a framework. Since the range of philosophies of science (isms) referred to in the marketing literature is broad, varying from ‘realism’ to ‘relativism’, from ‘positivism’ to ‘constructivism’ and from ‘structuralism’ to ‘post-structuralism/postmodernism’, first the different isms are grouped into four main groups/streams and then S-D logic is analyzed and classified according to these streams. The four streams are: object-orientation (realism, positivism, empiricism, and so on); subject orientation (constructivism, interpretivism, and so forth); intersubjective orientation (social constructionism, pancritical rationalism, methodological constructivism, and so on); and sign orientation (post-structuralism, postmodernism, and variations). S-D logic is mainly underpinned by an intersubjective orientation and has a huge potential for further development both in and for marketing if seen from a sign-orientated, post-structural perspective and linked to the theory of practices.
448

Service-dominant networks: an evolution from the service-dominant logic perspective

Löbler, Helge January 2013 (has links)
Purpose – This article seeks to advance a novel service network perspective, based on the service-dominant logic, designated as service-dominant networks (SDN). Design/methodology/approach – Service-dominant logic components serve to build and describe SDN. Specifically, resources and actors are key components, combined with activities and the process by which they become resources. A case study details the features of SDNs. Findings – Service-dominant networks exhibit unique, previously unaddressed features. According to the service-dominant logic, components only become resources when they are integrated; thus, they disappear as resources after their integration, which means SDNs are fugacious: they (be-)come and go. In addition, SDNs comprise one or more main intended activities that explain their existence, though these intended activities do not necessarily initiate any particular SDN. Rather, other critical incidents can initiate SDNs. Research limitations/implications – The features of SDNs proposed in this article have not been a focus of prior research. In particular, the dynamics and fugaciousness of SDNs are challenges for research and management. Originality/value – This article offers the first proposal of a novel, service-dominant network perspective. In a very general and abstract form, it identifies the features of SDNs.
449

Theorizing about resource integration through service-dominant logic

Peters, Linda D., Löbler, Helge, Breidbach, Christoph F., Brodie, Roderick J., Hollebeek, Linda D., Smith, Sandra D., Sörhammar, David, Varey, Richard J. January 2014 (has links)
Resource integration, as it relates to value creation, has recently been a key aspect of the discussions about service-dominant (S-D) logic. However, the majority of research pays relatively little explicit attention to the process of theorizing and the epistomological and ontological assumptions upon which the theorizing process is based. This article addresses these issues. The processes that relate to theorizing and developing strong theory are discussed. We then examine how to conceptualize ‘resources’ and ‘resource integration’ following differing ontological and epistemological assumptions that guide the theorizing process. Research recommendations to help navigate through the finer details underlying the theorizing process and to advance a general theory of resource integration are developed.
450

Anomalieresolution bei abduktivem Schließen: Experimente zur Hypothesenbildung und Strategieauswahl beim Problemlösen

Keinath, Andreas 29 April 2003 (has links)
Das Finden einer Erklärung für eine gegebene Menge von Daten oder Evidenzen wird als abduktives Schließen bezeichnet (Josephson & Josephson, 1994). Eine Vielzahl von Aufgaben lässt sich demnach als Abduktion charakterisieren, darunter beispielsweise medizinische Diagnose, die Suche nach Fehlern in technischen Systemen oder auch wissenschaftliches Entdecken (z.B. Charniak & McDermott, 1985). Für viele dieser Aufgaben ist der Umgang mit Anomalien von besonderer Bedeutung. Eine Anomalie ist im einfachsten Falle eine neue Evidenz, die einer bisherigen Erklärung für Daten widerspricht. Vor allem im Bereich des wissenschaftlichen Entdeckens weist eine Vielzahl von Studien darauf hin, wie wichtig das Erkennen und Lösen von Anomalien für erfolgreiches Problemlösen ist (vgl. Kuhn, 1962; Chinn & Brewer, 1998; Alberdi, Sleeman & Korpi, 2000). Die meisten Theorien abduktiven Schließens berücksichtigen die Bedeutung von Anomalien dagegen nur unzureichend (vgl. Klahr & Dunbar, 1988; Thagrad, 1989). Allerdings bietet das Modell von Johnson und Krems (2001, Krems & Johnson, 1995) einen spezifischen Mechanismus zur Anomalieresolution: Im Falle zweier sich widersprechender Evidenzen wird für beide Evidenzen eine Alternativerklärung konstruiert. Anschließend werden diese gegeneinander abgewogen. Indes wurde dieser Mechanismus bislang noch nicht empirisch belegt. Ziel der vorliegenden Arbeit war es einerseits zu klären, ob sich empirische Belege für den postulierten Mechanismus zur Anomalieresolution von Johnson und Krems (2001) finden lassen und andererseits zu prüfen, welche Einflussfaktoren und Strategien die Resolution von Anomalien beeinflussen. Es fand sich, dass abstrakte Ausgangshypothesen die Resolution von Anomalien erleichtern. Widersprach eine Anomalie einer abstrakten Ausgangserklärung, so lösten die Versuchsteilnehmer in Experiment 1 die Aufgaben häufiger, als bei einer konkreten Ausgangshypothese. In Experiment 2 zeigte sich zudem, dass bei einer abstrakten Ausgangshypothese weniger Experimente durchgeführt werden mussten um die Aufgabe korrekt zu lösen, dass häufiger spezifische Hypothesentests durchgeführt wurden und die Aufgaben auch schneller gelöst werden konnten. Unabhängig von der Ausgangshypothese testeten erfolgreiche Versuchsteilnehmer bevorzugt spezifische Hypothesen während hypothesenfreie Experimente dazu dienten, neue Hypothesen zu generieren. Demnach lösten die Probanden die Aufgaben durch Anwendung einer Mischstrategie, indem sie sowohl hypothesengestützt als auch hypothesenfrei nach neuen Daten suchten. Eine Einteilung der Versuchsteilnehmer in Theoretiker und Empiristen (Klahr & Dunbar, 1988) war dagegen nicht möglich. Das Ergebnis wurde in Anlehnung an Befunde von Smith et al. (1991) dahingehend interpretiert, dass eine solche Mischstrategie dabei hilft, die Komplexität der abduktiven Aufgabe zu reduzieren. Nicht bestätigt werden konnte in den Experimenten 2 und 3 die Modellvorhersage von Johnson und Krems (2001), dass die Versuchspersonen zwei Alternativerklärungen für die widersprechenden Evidenzen generieren um diese anschließend gegeneinander abzuwägen. Es wurde von den Probanden nur eine Alternativerklärung generiert, in Abhängigkeit davon, ob die an der Anomalie beteiligten Evidenzen kontextsensitiv oder kontextfrei erklärbar waren. Unter kontextsensitiven Evidenzen versteht man solche Evidenzen, die zu ihrer Erklärung auf andere Evidenzen angewiesen sind. Dagegen können kontextfrei erklärbare Evidenzen unmittelbar und ohne Einbeziehung des Kontextes erklärt werden. War eine kontextsensitive Evidenz an der Anomalie beteiligt, entweder als anomalieauslösende Evidenz oder als widersprochene Evidenz, so wurde immer diese alternativ erklärt. Waren dagegen beide an der Anomalie beteiligten Evidenzen kontextfrei erklärbar, so wurde nur für die anomalieauslösende Evidenz eine Alternativerklärung generiert. Zusammenfassend belegen die Ergebnisse der vorliegenden Arbeit die Bedeutung unterschiedlicher Hypothesentypen bei der Anomalieresolution. Abstrakte Ausgangshypothesen erleichtern nach Anomalieeintritt den Wechsel zu alternativen Hypothesen. Ist an der Anomalie eine kontextsensitive Evidenz beteiligt, wird diese bevorzugt alternativ erklärt. Im anderen Falle wird immer die anomalieauslösende Evidenz alternativ erklärt. Weiterhin zeigen die Ergebnisse, dass im Gegensatz zu dem von Johnson und Krems postulierten Mechanismus, menschliche Problemlöser bei der Anomalieresolution keine Optimierungs-strategie anwenden, sondern minimumsorientiert nach nur einer Alternativ-erklärung suchen und anschließend die Suche abbrechen (vgl. Gigerenzer & Selten, 2000). Dagegen fand sich als bevorzugte Strategie erfolgreicher Problem-löser das Testen spezifischer Hypothesen sowie hypothesenfreie Experimente zur Generierung von neuen Hypothesen.

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