1 - 3 of 3
rss atomLink to result list
Permanent link
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Presentation: 2020-02-07 11:00 Sal U1, Stockholm
    Zhang, Meng
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Naval Systems. KTH Royal Institute of Technology.
    Ice load prediction for design of ice-going ships for inland waterways2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    With increasing interest in utilizing the inland waterways (IWW) in European countries, the design of IWW vessels gains attention both from a transport efficiency and an emission control point of view. However, unlike in western and central European countries, in Nordic countries, e.g. Sweden, IWW ships must deal with ice on the fairway during every winter. Usually, IWW ships are designed without ice concerns and are structurally weaker compared to ships designed according to ice class notification from the classification societies. Developing such ships requires particular concerns since there is no strict requirements regarding ice class notifications for IWW ships. A primary challenge is to estimate both the global and local ice loads acting on the ship hull structure. To consolidate the design problems for IWW ice-going ships, Lake Mälaren is selected. Ice conditions, i.e. ice type and concentration, and ice data, e.g. ice thickness and ice flexural strength, are extracted and analysed for the ice load estimation. The ice mechanical properties have great influence on the ice load. Ice characteristics are studied based on empirical formulae and properties are calibrated by reference data.

    The deterministic approach is widely used to predict the ice loads. It is suitable when all variables, i.e. ship geometry and ice properties, are known and refers to rule-based design hereby. For first year light ice conditions in Lake Mälaren, the Finnish Swedish Ice Class Rule (FSICR) is widely used. The thesis uses guidelines from the Finnish Swedish Ice Class Rules as a reference and compare the results with other methods.

    The probabilistic approach, on contrary, is useful when certain variables are unknow, which are interpreted as random variables, for instance ice breaking pattern. Here the probabilistic method and ice-hull interaction mechanism are studied. The probabilistic method simplifies the ice pressure in relation to the contact area between the ice and the ship hull. It predicts maximum ice pressure acting on the ship hull based on field ice test data and ice exposure conditions. Such semi-empirical method can be used regardless of ship type and size. For this, a numerical model is introduced based on ice-hull collision mechanisms and the essential ice breaking characteristics. The physical mechanism is studied for idealizing ship-ice impact model. The idealization model includes the ice failure process, ice conditions and ship geometry. The ice failure is assumed to be initiated by crushing ice and followed by breaking due to bending failure. Ice properties are set as constant values without any variations. The stochasticity in interact process is represented by randomness in collision location and number of pieces of ice floe formed after breaking. An energy method is used to calculate the ice crushing force, indentation displacement and contact area. The ice bending scenario is simplified as an infinite plate resting on an elastic foundation under a concentrated load. Ice impact load and critical load can be obtained for global and local structural assessment respectively. The structural responses and structural strength of a representative panel at linear and nonlinear contexts are investigated as well. Ship structure is commonly designed with material yield strength as limit. However, the study shows a lighter structure can be achieved if plastic deformation is allowed without causing failure. Therefore, the design can be optimized with regards to ice loading capacity and weight control.

  • Presentation: 2020-02-18 14:00 E2, Stockholm
    Kytömäki, Olli
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Construction and Facilities Management.
    Digitalization and innovation in the real estate and facility management sectors - an ecosystem perspective2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Digitalization has become a topic of several presentations and discussions in real estate industry seminars in recent years. Often the speeches are about why the real estate industry needs digitalization, presenting threats and opportunities for the participants of the seminars. Still, real estate industry is conservative by nature and thus far property owners have not needed to innovate in order to stay in business. Therefore, a question arises that how do real estate owners react to the growing expectations about digitalization. On the other hand, relatively little is known about the innovativeness of real estate firms, as innovation research in built environment sector has largely focused on building project management phase organizations and facility management firms. Still, the real estate owners have a central role and a long-term perspective on the innovation in the built environment sector as a whole, as they are clients in all building life-cycle phases.

    Thus, this thesis purpose is to increase understanding of digitalization as a phenomenon in the real estate and facility management sectors: 1) by distinguishing the phenomenon in relation to existing research and 2) by generating new knowledge on digitalization in the field by explorative research.

    In order to distinguish the phenomenon in relation to existing research, the thesis provides a structured literature review that focuses on digitalization in the real estate and facility management sector. The main conclusion is that digitalization is a complex phenomenon, including multiple perspectives and conceptualizations, although, the literature converges on rather distinct topics of digital systems and methods, technology adoption and organization and management. Additionally, the review provides a discussion of opportunities for further research. An argument is made for sociotechnical perspective to provide opportunities for better managerial comprehension on the complex phenomenon.

    In order to generate new knowledge on digitalization in the field, particularly, on the innovativeness of real estate firms, the thesis provides summaries of two papers. The first paper focuses on the innovation processes in the real estate owner organizations and the second paper focuses on the innovation ecosystem that comprises of actors that contribute towards common innovation goals. The papers are based on interviews with the various real estate industry actors and document analysis. The papers converge on results, concluding that the real estate owners have invested in resources and capabilities for innovation, but it is still challenging for them to act on the digital threats and opportunities. Additionally, the second paper develops an operationalizable definition and methodology for research on innovation ecosystems, which has relevance for the more general literature on innovation and strategy.

    Thus, this thesis distinguishes digitalization as a phenomenon in the built environment management sectors and increases understanding on the innovativeness of real estate firms’ and other actors that contribute to the innovativeness of the real estate sector as a whole.

  • Presentation: 2020-02-21 10:00 E3, Stockholm
    Lind, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Sustainability Assessment and Management.
    Designing a certification system for sustainable urban areas: Key considerations and their implications for the development of Citylab Post-Construction2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In future development dealingwith ongoing global urbanisation and sustainability challenges,urban development is often seen asa key component. To support urban development, various certification systems that define 'sustainable'buildingsor urban areashave been developed world-wide.For a Swedishcontext, Sweden Green Building Council (SGBC) has developed Citylab as asupporttool forsustainable urban development. This tool contains several certification systems and a guiding document forthe planning and construction phasesof urban development. The intention from start has been to include also a certification systemfocusing on follow-up requirementspost-construction inurban development projects, butthe role and function of thiscertification system havenotbeenspecifiedby SGBC. Inthis licentiate thesis,Researchthrough Design (RtD) and a transdisciplinary approachwere appliedto contribute to thedevelopment ofa credibleandready-to-use certification system for sustainable urban areas in a post-construction phase, called Citylab Post-Construction.Through that process the thesis also identifieskey considerations when designing such a certification system.There is little information on how existingcertification systemsfor sustainable urban development were developed,andthere is no well-known and widely used framework for their development. To guide the development of Citylab Post-Construction,a framework of key considerations was formulated,based on a literature review. The framework defines(1) benefits a certification system should provide, (2) principles it needs to fulfil in order to provide those benefits and (3) how to handle the principlesin the developmentprocess. Using theframework in the research presentedinthis thesis madeit clearer what was at stake in each decision and thus the development process more transparent.To identify needs and ideas forCitylabPost-Construction, potential future users of the certification systemwere interviewed. No consensus was reached regarding the role and function the certification system should have,but fouralternatives wereformulated. By comparing thesealternatives with the principles in the framework, differences and shortcomingswere identified. Situationsin whichdifferent principles within the framework may conflict with each otherwere also identified, e.g.the most scientifically credible solution may not always be practically feasible. Thus,the principles cannot all be fulfilled simultaneouslyand mustbe prioritisedand balancedagainst each other. Overall, thisrevealed aneed for deliberativeand transparent decisions regardingthe role and functionofthecertification system,and which principles are prioritisedin decision-making. For the specific case of developing CitylabPost-Construction, it was decided that the system should assess how urban areasperform in terms of sustainability, i.e.assess whether implemented measures have sufficient impact in terms of sustainability. Measures implemented to achieve that performance were not to be included in the assessment.Citylab Post-Construction includes two types of indicatorsfor evaluatingthe sustainability performance of an urban area: First, general indicators that assess sustainability aspects of relevance to all urban areas,and for which the level of performance required forcertification is the same for all urban areas;second,site-specificindicatorsthatareformulatedfor each individual urban areato be certifiedandassesssustainability aspectsimportantin the local context thatare not covered by the general indicators. When choosinggeneral indicators to include in Citylab Post-Construction, indicators already used in different contextswere long-listed, including e.g. Agenda 2030, planetary boundariesand Sweden's Environmental Objectives. Thelist was then processedby working groups comprisingdifferentstakeholders and competencies. Theirsuggestionswerefurther processed by the project teamand discussedwith a reference group,resultingin15 indicators to be refinedtogetherwith experts in each subject area. The entire certification system wassent out for public consultationand underwent workshop testing,where the indicators were testedon two different urbanareas.Based on feedback fromthe public consultation and workshop testing, the certification system was finalised. The Citylab Post-Construction manual developed will be used by SGBC in future certification processes.Based on this work, some conclusions can be drawn regarding the development of certification systems. First, the workhighlighted the importance of using a design-driven and transdisciplinary way of working,starting with the needs of future users,to clarify needsthat the certification systemshould meet. This can help distinguish thetype of certification system that willbe developed from other potentialsystems.Second, the framework of important considerations helpsidentifydifferent principlesthat must be balanced, based on the type of certification system intended. The framework can also be used when analysingexisting systems,to reveal how different principles have been balanced and prioritised. This can lead toa deeper understanding of differences between certification systems,andto a discussion on what kind of assessment a certification system should implyand how they should be used in different contexts. Third,the work in this thesis indicated that development of certification systems in accordance with the framework should use a transdisciplinary approach. This helps tobalancetheprinciples in the framework and to definesustainability, as thatrequires a discussion between different actors and different competencies. To confirm whether the certification system balancesthe principlescorrectly, different types of tests can be used iteratively during the developmentprocess. In this thesis, the development ofCitylab Post-Constructionis discussed and justified in a more transparent way than for many other certification systems. Whileachievingsustainable development in society as a wholewill requiremore than certification of urban areas, Citylab Post-Construction can support urban development as a component in a sustainable society.