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  • 301.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Malmqvist, Tove
    KTH.
    Miljövärdering av bebyggelse: metodbeskrivning EcoEffect-metoden2009Rapport (Annet vitenskapelig)
    Abstract [sv]

    Miljöbedömning i EcoEffect omfattar extern och intern miljöpåverkan. Bedömningen av extern miljöpåverkan syftar till att ge ett mått på besvär för människor som användningen av en fastighet, byggnad eller ett byggmaterial bidrar till att skapa på andra platser, t.ex. klimatpåverkan. Miljöbelastningar mäts som ekvivalenter bidragande till olika miljöeffekter. Sammanvägda bedömningar visas som %, beräknade som miljöbelastning per brukare av t.ex. en byggnad dividerat med motsvarande miljöbelastning per capita i landet. Miljöbelastningar kan också beräknas t.ex. per produkt eller per m2 våningsyta. Bedömningen av intern miljöpåverkan syftar till att ge ett mått på risken för att människor som vistas i en byggnad eller på en fastighet skall drabbas av besvär till följd av den fysiska närmiljön. Vid både extern- och intern miljöbedömning är besvär för människor utgångspunkten för utvärderingen. Även miljöproblem som uppträder i naturmiljön, såsom bristande biologisk mångfald, bedöms i termer av problem för människor. Graden av besvär för människor mäts som brister i livskvalitetkomponenter. Det är mått som används inom socialmedicin och som vi har vidareutvecklat. Dessa komponenter är: Rörlighet, Klara sig själv, Vardagsaktiviteter, Smärta/ obehag, Oro/nedstämdhet/irritation och Intellektuell förmåga. Varje typ av problem för människor klassas med avseende på dessa komponenter och en störningsvikt baserat på medelvärdet beräknas. Störningsvikten gånger störningstiden för ett problem kallar vi ”skadevärdet”. Konceptet kan betraktas som en vidareutveckling av DALY-systemet (Disability Adjusted Life Years). För alla typer av problem för människor kan man beräkna ett skadevärde som beskriver dess relativa betydelse i förhållande till andra problem. Dessa skadevärden används som vikter i EcoEffect när man vill se ett sammanvägt resultat av många olika sorters miljöpåverkan. Detta är ofta är en förutsättning för att kunna använda miljöbedömningar praktiskt. Rapporten beskriver hur man beräknar miljöbelastningar av olika slag, tar fram störningsvikter och skadevärden för såväl externa som interna miljöproblem. Även grunderna för utvecklingsarbetet beskrivs. Metodiken är ny och kan tilllämpas systematiskt för alla typer av miljöpåverkan som leder till fysisk eller psykisk ohälsa.

  • 302.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Malmqvist, Tove
    Miljövärdering av bebyggelse: metodbeskrivning för EcoEffect2005Rapport (Annet vitenskapelig)
  • 303.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Malmqvist, Tove
    Svenfelt, Åsa
    Carlson, Per-Olof
    Erlandsson, Martin
    Andersson, Johnny
    Winzell, Helene
    Finnveden, Göran
    Lindholm, Torbjörn
    Malmström, Tor-Göran
    Miljöklassning av byggnader: Slutrapport april 20082008Rapport (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Den här rapporten presenterar en metod för att miljöklassa byggnader med avseende på energi, innemiljö och kemiska ämnen. Rapporten presenterar också några särskilda miljökrav för byggnader med eget VA-system.

    Det övergripande syftet med ett nationellt miljöklassningssystem är att bidra till en hållbar bygg- och fastighetssektor. Arbetet ska resultera i en praktiskt tillämpbar metod för miljöklassning av byggnader som är väl förankrad i byggsektorn och hos myndigheterna. En allmänt accepterad miljöklassning av yggnader kan bli ett starkt incitament för byggherrar, fastighetsägare, fastighetsförvaltare och bebyggelsens användare att påskynda en utveckling mot en miljöanpassad och hälsoinriktad byggsektor.

    En av de viktigaste utgångspunkterna för arbetet med att ta fram ett miljöklassningssystem har varit Bygga-bo-dialogens1 mål att alla nya hus och 30 procent av det befintliga byggnadsbeståndet ska vara miljöklassade senast år 2009. Denna ambition har medfört att enkelhet har varit ett viktigt mål för miljöklassningsarbetet. Balansen mellan trovärdighet och

    enkelhet har varit viktigt för arbetet.

  • 304.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Sundqvist, Åsa
    Finnveden, Göran
    Eriksson, Ola
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Development of an Environmental Classification System for Buildings through a New Kind of Dialogue between Stakeholders and Researchers.2006Inngår i: Environment, health and sustainable development: IAPS 19 Conference Proceedings on CD-Rom / [ed] Mustafa K. Tolba, Aleya Abdel-Hadi, Salah Soliman, 2006Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Aims and Objectives: The objective of this research project is to develop a system for environmental classifications of buildings, taking into account the building sector's requirements and expectations as well as international and national research findings. The classification system will deal with both new and existing buildings and will encompass indoor environment, efficient use of energy, efficient resource management and hazardous substances. The aim of this paper is to present, discuss and draw conclusions from the first research phase of the project.Context: The building sector is responsible for about 40% of all of energy and material use in Sweden and hence needs to become more sustainable. Major stakeholders in the Swedish building and property sector, including the Swedish government, municipalities and companies, have for the first time started a coordinated work to achieve a more sustainable building sector. This effort, called the dialogue project, embrace a number of commitments for each participant. One of these is to promote that all new buildings and 30% of the existing ones should be classified with respect to health and environmental impact before 2010. A general and broadly accepted system for classification of environmental performance is expected to have a large impact on management, retrofit and new designs. In accordance with this aim two research & development projects were initiated.Method: The classification system is developed by researchers in collaboration with a group of companies and municipalities who support the work practically and financially. They participate in seminars and interviews and they will test modules of the classification system along the development process. The first phase of the project has included a number of inventories: inventory of current bills, legislation and policy targets relating to environmental impact in the building sector; Interviews with key informants representing authorities and stakeholders ; inventory of national and international tools for environmental assessment of buildingsConclusions: The result will focus on conclusions from the inventories seen from three different points of views - demands from the society, demands from the sector and scientific demands. To which extent they are in harmony or contradictory will be examined. Finally some key features and elements of the anticipated classification system will be extracted and presented.

  • 305.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Svenfelt, Åsa
    KTH Miljöstrategisk Analys.
    Malmqvist, Tove
    KTH Miljöstrategisk Analys.
    Finnveden, Göran
    KTH Miljöstrategisk Analys.
    Eriksson, Ola
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Development of an environmental rating tool for buildings through a new kind of dialogue between stakeholders and researchers2009Inngår i: ArchNet - I J A R, ISSN 1938-7806, Vol. 3, nr 1, s. 116-130Artikkel i tidsskrift (Fagfellevurdert)
  • 306.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Wallhagen, Marita
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Study of international policies, Sweden: National initiatives for reducing the environmental impact of the building sector2006Rapport (Annet vitenskapelig)
  • 307.
    Glaumann, Mauritz
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Wallhagen, Marita
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Survey of sustainable approaches in Sweden2008Inngår i: Sustainability of Constructions: Integrated Approch to Life-time Structural Egineering / [ed] Braganca L et al, Possendorf: Addprint AG , 2008, s. 2:78-2:95Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 308.
    Gong, Pu
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Guo, Hua
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Post-Correction of Analog to Digital Converters2008Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    As the rapid development of the wireless communication system and mobile video devices, the integrated chip with low power consuming and high conversion efficiency is widely needed. ADC and DAC are playing an important role in these applications.

    The aim of this thesis is to verify a post-correction method which is used for improving the performance of ADC. First of all, this report introduces the development and present status of ADC, and expatiate its important parameters from two different classes (static performance and dynamic performance). Based on the fundamental principle, the report then focuses on the dynamic integral non-linearity modeling of ADC. Refer to this model, one post-correction method is described and verified.

    Upon the face of post-correction, this method is to modify the output signals which have been converted from analog to digital format by adding a correction term. Improvement made by the post-correction needs to be checked out. Thus the performance analysis mainly relay on the measures of total harmonic distortion and signal to noise and distortion ratio is also included in this thesis.

  • 309.
    Gosztolai Eriksson, Stefan
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Forsgren Stistrup, Michael
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Importflöden med container till mellansverige: Kartläggning av importflöden2009Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Företag x fungerar som en knytpunkt ur ett logistikperspektiv på orten och här sammanstrålar mycket av godsflödena som kommer eller avgår med båt. Stora delar av exportflödena består av stål och trä där stora importflöden i huvudsak består av kaffe och olja.

    Nulägessituationen är som sådan att det är en ojämn fördelning andel importflöden med container jämfört med exportflödet. Skälet är att vi befinner oss på en plats med mycket tillverkande industrier som exporterar varor ut i världen. Resultatet av detta är att andelen import via Företag xs containerterminal är 25% jämfört med 75% i export. Ett problem som uppstår i samband med detta är att tomma containrar måste skeppas till Företag x för att möta den, i nuläget, större andelen export. Att skeppa tomma containrar är kostsamt och icke önskvärt. Önskvärt är emellertid nu att på olika sätt stimulera aktörer att använda Företag x som anlöp och därmed plana ut en ojämn fördelning på godsflöden till och ifrån regionen.

    Person X, vid Företag x är marknadsdirektör och arbetar kontinuerligt med frågor av typen ovan. Syftet med arbetet är att göra Företag x med attraktiv som hamn, där man vill få kunderna att inse fördelar med att med att komma till Företag x. Omfattande investeringar görs för att Företag x ska kunna erbjuda kunderna, rederierna, tjänster och kapacitet som skulle resultera i att allt fler väljer att importera gods via Företag x. I nuläget är Göteborgs hamn den största i Sverige, Företag x är den tredje största.

    På uppdrag av Företag x och Person X har vi fått i uppdrag att kartlägga importflöden på regionen som begränsas från Stockholm till Östersund som nordligaste punkt. Regionens omfattning är framtagen i samråd med Person X och syftar till att innefatta de geografiska slutdestinationer för gods som passerar Företag x. Mycket av det gods som hamnar inom den avgränsade regionen kommer emellertid från andra hamnar i Sverige också.

    Person X är alltså intresserad av varuflöden som kommer till regionen, och avser att använda resultatet av vår studie som grund för vidare utredning av nulägetssituationen och möjligheter att sätta in insatser för att stimulera importflöden via Företag x, med container.

    Slutsatsen vi gjort är att godsflöden följer generellt befolkning och inkomst. Vi har dessutom gjort slutsatsen att importflöden generellt ökat de senaste åren. 

  • 310.
    Grip, Katarina
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Pålsson, Jennifer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för industriell ekonomi.
    Hur lagerhanteringssystem och artikelidentifiering kan bidra till logistisk effektivitet: En fallstudie på Nefab i Runemo2009Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Warehouses are a key aspect of modern supply chains and play a vital role in the success or failure of businesses today. Figures from the USA indicate that the capital- and operating costs of warehouses represent about 22 % of a company’s logistics costs while figures from Europe indicate 25 % (Baker & Canessa, 2009). Because warehousing is such an important function within a company, the authors chose to focus on this in their thesis. The purpose of this thesis has been to examine the significance of a Warehouse Management System (WMS) and item identification with attention to logistic efficiency. With this as a starting point, the thesis also intends to examine the needs and possibilities with a WMS and some sort of item identification at a specific company and also present suggestions of how to move forward with this type of work.

  • 311.
    Guadalfajara, Mateo
    Högskolan i Gävle, Institutionen för teknik och byggd miljö. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Interference between supply jet and room surfaces in ventilated room - A model study2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 312.
    Guo, Wanli
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Explaining the Difference on CI Behavior in HK and Sweden by using Hofstede’s Culture Theory2008Independent thesis Advanced level (degree of Magister), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    Continuous improvement (CI) is a well-known approach within total quality management. Based on it, Continuous Improvement Behavior Model (CIBM) is a model that put behavioral patterns in work practice in focus, and is associated with learning process and routines across the whole organization. The purposes of this thesis are twofold: firstly, to analyse the differences in CI behavior between firms in Sweden and Hong Kong (HK); secondly, to analyse the reasons for these differences by using Hofstede’s culture theory. This study was based on data from the 2nd international CINet survey and IBM questionnaire survey, limited to the culture in Hong Kong (HK) and Sweden. The finding of this comparative study showed that there are significant differences in CI behavior in the following aspects:

     The view in HK is that the interest of the group should prevail over the individual’s, because there has a proverb”unity is power” in Chinese culture. Firms in Sweden are more concerned with the interests of individual’s.

     Employees in Hong Kong would like to use organizational formal tools and techniques to deal with a problem, although it is a society characterized by weak uncertainly avoidance. But firms in Swedish believe that problems can be solved without formal rules.

     Employees in HK emphasizes cooperation and relationship in the process of working, while it is influenced by the culture of”guanxi” and collectivism. In comparison, Swedish employees care less about relationship.

     People in HK pay much attention to the personal development, due to a competitive environment and a long-term orientated culture manifested as:”it is never too old to learn”. Swedes, however, want to study when it is necessary.

     Managers in HK are willing to support CI activities by provide sufficient resources and self-discipline influenced by the Chinese culture of ”set an example”. Correspondingly, Swedish firms don't have the regulation about what manager necessary should do.

    This is the first study that tries to explain the difference on CI behavior by using Hofstede’s culture theory in HK and Sweden, using a statistical method to test 34 behaviors in CI Behavior Model. It has to mention that there have 17 behaviors in the total behaviors which have been proved to be different, and 11 of these behaviors can be explained by Hofstede’s model in this thesis. There are also some other factors that can explain the differences in CI behaviors.

    In this thesis, it is shown that size of company matters. Possible explanations provided by other cultural theories are also presented.

  • 313.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Cole, Ivan
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Esposito, M. A.
    Geographical Information Systems for Sustainable Management of Built Environment2004Inngår i: Building for the Future: The 16th CIB World Building Congress 2004, 2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the building and construction sector all features are location based. The world of geographic information and application orientation is moving extremely fast, and there is a real danger that the slow uptake of new technology and applications in the building sector will again leave the sector trailing behind, also implying a loss in sustainable development and competitive edge. In order to deal with this issue CIB in 1996 established the task group CIB/TG20-GIS. Based on the report CIB 256 from this group and its recommendations, CIB in 2000 established the working commission CIB W106 "Geographical Information Systems", with the overall objectives to provide an international platform for R and D of GIS in the building sector. The W106 has members from 14 countries/organisations and will present its progress report at this Congress, while its final report with conclusions and recommendations is due for the 10DBMC conference in 2005. The work is divided into the following four Tasks: TG1 - GIS-requirements and availability of geographic standards-, data and infra-structures, TG2 - GIS-based analysis and modelling of flow and distribution of materials in the built environment, TG3 - Spatial dynamic modelling for simulation of the interaction between the natural and the built environment, TG4 - GIS in Education and Info sources. Objectives and work programme for each of these tasks are given and illustrated with examples, taken from state-of-the-art reports on the use of GIS elaborated by the participating countries/organisations.

  • 314.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Cole, Ivan
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Esposito, M. A.
    Vanier, D. J.
    CIB W106 Geographical Information Systems: Work Period Report2005Inngår i: 10th International conference on durability of building materials and components: Lyon, France, 17-20 April 2005, 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the building and construction sector all features are location based. The world of geographic information and application orientation is moving extremely fast, thus challenging the building sector to facilitate and implement this new technology and applications. In order to deal with these issues CIB in 1996 established the task group CIB/TG20-GIS. Based on the report CIB 256 from this group and its recommendations, CIB in 2000 established the working commission CIB W106 - Geographical Information Systems., with the overall objectives to provide an international platform for R&D of GIS applications for the built environment, and to promote and encourage the use of GIS in the building sector. The W106 has members from 14 countries/organisations and will present its final report for work period 2001-04 due for the 10DBMC conference in 2005. The work is divided into the following four Tasks: TG1- GIS-requirements and availability of geographic standards-, -data and infra -structures, TG2- GIS-based analysis and modelling of flow and distribution of materials in the built environment, TG3- Spatial dynamic modelling for Simulation of the interaction between the natural and the built environment, TG4- GIS in Education and Info sources. Objectives and work programme for each of these tasks are given and illustrated with examples, taken from state .of-the-art reports on the use of GIS elaborated by the participating countries/organisations. With the rapid development of IFC based standards for digital object oriented models of building products there is a huge need for property sets, such as environmental exposure data, reference service life, service life models, factor distributions, LCA and LCC data, which can be linked directly to the building elements. The significant drive within the AEC/IFC to provide for relevant location based data (GIS) via IFC format will be a major facilitator for access to relevant durability data on the specific building site. It is concluded that time is ripe for a broad implementation of GIS based applications in the building sector. Hence, it is recommended that the work programme of W106 for the coming working period includes a focus on support for an IFC based fully integrated design and planning process for the built environment, as well as a close link to the European based R&D frameworks for integrated life cycle management of the built environment.

  • 315.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Krigsvoll, Guri
    Gussiås, Arne
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Life Cycle Management of Built Environment: An ICT based concept and some Cases2004Inngår i: Proc. of CIB World Building Congress, 2004Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 316.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Krigsvoll, Guri
    Lisö, K. R.
    Thiis, T.
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Environmental Characterisation and Mapping with respect to Durability2005Inngår i: 10th International conference on durability of building materials and components, 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Service life planning calls for characterisation and classification of the exposure environment for the constructed asset(s) in question. Lack of knowledge of environmental exposure data and models among the building sector players is an important barrier for further progress towards service life prediction. The ever more evident climate change highlights even more the need for data and models on the exposure, when it comes to address its impact on the built environment. In general, requirements for establishing and implementing systems for quantitative characterisation and classification of durability of materials and components are: 1) well defined, and relatively simple damage functions for the materials in question, 2) availability of environmental exposure data/loads, including methods and models for assessing their geographical distribution, and 3) user friendly IT systems for storage, processing and modelling the environmental loads onto structures. Service life functions related to environmental degradation are today available for a range of building materials and components. As for availability of environmental data and models, as well as proper IT systems, it is shown that for most European countries, such data and models are available from meteorological offices and the environmental research area, and that these data and the work performed are directly applicable for service life planning and life cycle management of constructed assets. A short review of some of the most applicable models for environmental exposure and for degradation and damage of building materials and structures is included. The global climate system is likely to undergo changes, regardless of the implementation of abatement policies under the Kyoto Protocol or other regimes. Both the functionality of the existing built environment and the design of future buildings are likely to be altered by climate change impacts, and the expected implications of these new conditions are now investigated. The data and models are often directly exhibited in computer-based systems, often on GIS based platforms. With the rapid development of IFC based standards for digital object oriented models of building products there is a huge need for property sets, such as durability and service life data, linked directly to the building elements. The significant drive within the AEC/IFC community to provide for relevant location based data (GIS) via IFC format will be a major facilitator for access to site specific durability data, described by degradation models containing environmental (and other) degradation factors.

  • 317.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Krigsvoll, Guri
    Quantitative characterisation and classification of environmental degradation loads2006Inngår i: Predictive and Optimised Life Cycle Management: Buildings and Infrastructure / [ed] Asko Sarja, London: Taylor & Francis , 2006, s. 300-337Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 318.
    Haagenrud, Svein
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Stordahl, Petter
    Eriksson, Bengt
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Riks, Eva
    Krigsvoll, Guri
    A PC based system for maintenance management of buildings: General description2001Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Europe's rich culture in wooden buildings are rapidly degrading due to environmental impact, wrong conservation techniques and lack of resources and technological tools for appropriate conservation. These issues were addressed in the former EU-project ENV4-CT95-0110 Wood-Assess , which has been finalised (Haagenrud et al, 1999). In a new EU-project MMWood (ENV4-CT-98-0796) a PC-based system for maintenance management of buildings has been developed. The project had the following objectives: To develop and validate for the SMEs an integrated Maintenance Management system for historic buildings, adapted to the needs and purposes of various user group levels. Based on the Wood-Assess concept and results the modular GIS (Geographical Information System) based system, MMWood, will specifically contain - A documentation system for outer and inner parts of buildings and components; - Soft- and hardware tools for the building inspection in the course of maintenance tasks; - An environmental risk factor assessment module; - A standardized maintenance assessment module; - A cost and maintenance planning module. Main developments from the Wood-Assess project are the inclusion of the maintenance management phase, extension of the damage atlas to include also adjoining materials in wood constructions, rendering, brick and natural stone, and a fully integrated field inspection system, allowing the user to import/export all background and recorded data between the field inspection and the total maintenance management system.

  • 319. Hagström, Tom
    et al.
    Kjellberg, Anders
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Arbetsvärderingars stabilitet och föränderlighet i ett genusperspektiv: sjuksköterskor och högskoleingenjörer i övergången från yrkesutbildningen in i arbetslivet2005Bok (Annet vitenskapelig)
  • 320. Hagström, Tom
    et al.
    Kjellberg, Anders
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Changeability and gender related challenges of work values2004Inngår i: 28th International Congress of Psychology, Beijing, 2004, 2004Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Changeability of work values was studied by longitudinal analyses of nurses and engineers from the Stockholm area in Sweden. Questionnaires were completed by 173 male and 48 female engineers and 353 female and 31 male nurses at three measurement occasions covering about four and half years from the end of their vocational education. Women's ratings of Social relations and Altruism remained higher than men's while women & acute; ratings of Benefit/career and Influence increased which eliminated the initial gender difference. The changeability of work values is discussed in terms of challenges and norms in working life.

  • 321.
    Hagström, Tom
    et al.
    Department of Education, Stockholm University, Sweden.
    Kjellberg, Anders
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Stability and change in work values among male and female nurses and engineers2007Inngår i: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 48, nr 2, s. 143-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gender related changes of work values were analyzed in a longitudinal questionnaire study of 173 male and 48 female engineers and 353 female and 31 male nurses at three measurement occasions covering about four and half years from the end of their vocational education. At all occasions, Social relations were rated as more important by women than by men and Altruism was given higher ratings by the nurses than by the engineers. Within both occupations women’s mean Altruism ratings were higher than men’s mean ratings, and in all groups except male engineers the mean ratings dropped between the three occasions. Women’s ratings of Benefits and career and Influence were strengthened in both occupations, thereby eliminating an initial gender difference. The stability of work values is discussed in terms of challenges and norms in working life.

  • 322.
    Haimene, Rachel N.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Presentation of the Namibia Zero Order Stations and Information Site for Directorate of Survey and Mapping2007Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project is focused on the presentation of the Namibia Zero Order Stations, including the descriptions of the 21 stations across the country and to create information site for Directorate of Survey and Mapping in Namibia. The main reason for the implementation of web site is for the distribution of information and data to domestic and international clients. Most of the materials and information used in this project were available in digital format. Some information was collected from Directorate of Survey and Mapping of Namibia, Swedesurvey of Sweden, and Asci of Sweden as well as from the internet and library facilities. As such it was very important to analyse and display geo-spatial data before creating web site. The computer makes it possible to create a link between filed documents, maps, graphic documents and other related information using hyperlinking. Therefore the computer made the world easier to communicate and mapping via internet.

  • 323. Haines, M M
    et al.
    Stansfeld, S A
    Brentnall, S
    Head, J
    Berry, B
    Jiggins, M
    Hygge, Staffan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    The West London Schools Study: the effects of chronic aircraft noise exposure on child health2001Inngår i: Psychological Medicine, ISSN 0033-2917, E-ISSN 1469-8978, Vol. 31, nr 8, s. 1385-1386Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background. Previous field studies have indicated that children's cognitive performance is impaired by chronic aircraft noise exposure. However, these studies have not been of sufficient size to account adequately for the role of confounding factors. The objective of this study was to test whether cognitive impairments and stress responses (catecholamines, cortisol and perceived stress) are attributable to aircraft noise exposure after adjustment for school and individual level confounding factors and to examine whether children exposed to high levels of social disadvantage are at greater risk of noise effects. Methods. The cognitive performance and health of 451 children aged 8-11 years, attending 10 schools in high aircraft noise areas (16 h outdoor Leq > 63 dBA) was compared with children attending 10 matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Results. Noise exposure was associated with impaired reading on difficult items and raised annoyance, after adjustment for age, main language spoken and household deprivation. There was no variation in the size of the noise effects in vulnerable subgroups of children. High levels of noise exposure were not associated with impairments in mean reading score, memory and attention or stress responses. Aircraft noise was weakly associated with hyperactivity and psychological morbidity. Conclusions. Chronic noise exposure is associated with raised noise annoyance in children. The cognitive results indicate that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult cognitive tests in children.

  • 324.
    Halim, Humam
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Evaluation of a  Near Field Scanner For  Active Measurements of Mobile Phones2009Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

        The radio performance measurements of terminal antennas require expensive investments and they are often performed in anechoic chambers. Now a days measurement techniques using wheeler cap, reverberation chamber, etc have become popular. But these methods are used for measurements either during the design or production or in-network testing phases but not for all. Hence EMSCAN, a Canadian company, has come up with a device called Lab express near field scanner to counter this problem.

     

    In this thesis an attempt is made to study the EMSCAN near field scanner by looking into architecture and design aspects of this device. Moreover, the capability of the device to measure the radio performance of the terminal antennas in terms of radiation pattern and total radiated power (TRP) is also studied and anlaysed.The analysis of the TRP and radiation pattern measurements of the terminal antennas is done by comparing the EMSCAN measurement results of 10 commercially available mobile phones with that of CTIA approved Satimo SG24 chamber.

     

    The TRP and radiation pattern measurements are done for GSM 900 MHz and DCS 1800 MHZ low bands i.e.975 and 512 respectively. Furthermore, the dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is tested by measuring the TRP and the radiated power of a single mobile phone.

     

    The measurement results after comparison suggest that there is a correlation of around 79% at 1800 MHz and 49% at GSM 900 MHz among the two methods. This leads to the conclusion that EMSCAN scanner cannot replace the anechoic chambers for estimating the radio performance of terminal antennas. The results obtained by measuring the mobile phone in 8 different positions suggest that there is no significant difference in the TRP measured. There is a difference of 1.25dB was observed between the maximum and minimum TRP measured in two different positions on the near field scanner.

     

    The results obtained by both the methods are verified by computing the TRP and radiation pattern in Matlab.The Matlab results agrees more with the EMSCAN results than Satimo SG 24 chamber results.

  • 325.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Adaptation and validation of a predictive GIS based maintenance management system2003Inngår i: Innovation in Construction and Real Estate: proceedings of the CIB Student Chapters International Symposium, Department of Building and Real Estate, the Hong Kong Polytechnic University, 26-27th September, 2003, Hongkong: Hong Kong Polytechnic University , 2003Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The amount of deteriorating civil engineering structures and buildings are constantly growing. This ongoing process will make a great impact on resources, environment, human safety and health. Today there is a need of a uniform methodology and systems for maintenance organisation and management.

    To manage such issues above two consecutive EU-projects were launched. The EU-project ENV4-CT95-0110 “System and Methods for Assessing Conservation State and Environmental Risks for Outer Wooden Parts of Cultural Buildings” (Wood-Assess) and its successor ENV4-CT98-0796 “System for Maintenance Management of Historic (Wooden) Buildings” (MMWood) achieved all the objectives and resulted in a Maintenance Management System (MMS) version 1.0 software application. The MMS was heavily developed according to the ISO 15686 series “Service life planning” requirements.

    A predictive GIS based Maintenance Management System has to correspond to the user needs and co-operate with other systems. It is also of great importance that the system is corresponding to the user-, national- and international standards. To fulfil those requirements the system has to be open and integrative and must cope with adaptations and adjustments of the system.

    The MMS software application will be the kernel in the ongoing development of the more comprehensive Life Cycle Management System (LMS). It is therefore important to make sure that the MMS is adaptable to LMS and cope with add-in modules.

    By using a slab bridge located in the City of Gävle, Sweden, the adaptation and validation of MMS was executed. The MMS enables systematic structuring of assets and condition assessments of buildings and structures and does also manage to link pictures, drawings, maps, geographic information system (GIS) functionalities and documents. The system administrator does some part of the adaptation and some part has to be adapted by the user himself.

    In the near future the MMS will be able to cope with life cycle cost (LCC), life cycle performance (LCP) and life cycle ecology (LCE) add-in applications to achieve full LMS status.

  • 326.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Application of a non-steady state model for estimation of Time of Wetness2004Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Moisture is of great importance due to a number of degradation processes. The moisture either accelerates or reduces the degradation velocity depending on the degradation mechanism and material. The degradation of building materials is thus dependent on the time during when the material is exposed to moisture. A model of how the time of wetness on a surface will vary, due to different climate conditions including impact of rain and solar radiation, is developed and presented. Due to the results of some test runs of the developed model, not surprising, both wind and the colour of the surface will have an impact on the time of wetness on a non-hygroscopic surface. However, the model is only tested during some specific climatic conditions and has to be tested in several different climatic conditions with real climatic data of rain and wind.

  • 327.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Development and Adaptation of a Life Cycle Management System for Constructed Works2005Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Lifetime Engineering (or Life Cycle Engineering) is a technical approach for meeting the

    current objective of sustainable development. The approach is aimed to turn today’s reactive

    and short-term design, management and maintenance planning towards an optimised and

    long-term technical approach. The life cycle based management and maintenance planning

    approach includes condition assessment, predictive modelling of performance changes,

    maintenance, repair and refurbishment planning and decisions. The Life Cycle Management

    System (LMS) is a predictive and generic life cycle based management system aimed to

    support all types of decision making and planning of optimal maintenance, repair and

    refurbishment activities of any constructed works. The system takes into account a number of

    aspects in sustainable and conscious development such as human requirements, life cycle

    economy, life cycle ecology and cultural requirements. The LMS is a system by which the

    complete system or parts thereof, works in co-operation or as a complement to existing

    business support systems. The system is module based where each module represents a subprocess

    within the maintenance management process. The scope of this thesis is focused on

    development and adaptation of the predictive characteristic of LMS towards a presumptive

    user. The objective is to develop and adapt a Service Life Performance Analysis module

    applicable for condition based Facility Management System in general and for condition

    based Bridge Management System in particular. Emphasis is placed on development and

    adaptation of a conditional probability based Service Life Performance Analysis model in

    which degradation models and Markov chains play a decisive role. The thesis deals also with

    development and adaptation of environmental exposure data recording and processing, with

    special emphasis on quantitative environmental classification in order to provide a simplified

    method of Service Life Performance Analysis.

  • 328.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Development and Adaptation of a Life Cycle Management System for Construction Works2006Inngår i: Lifetime Engineering of Civil Infrastructure : Honoring the career of Professor Asko Sarja, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lifetime Engineering (or Life Cycle Engineering) is a technical approach for meeting the current objective of sustainable development. The approach is aimed to turn today’s reactive and short-term design, management and maintenance planning towards an optimised and long-term technical approach. The life cycle based management and maintenance planning approach includes condition assessment, predictive modelling of performance changes, maintenance analysis and maintenance, repair and refurbishment (MR&R) planning and decisions. The change towards a predictive approach requires generic systems, applicable to different maintenance manager organisations with different MR&R strategies, managing different types of construction works. The newly developed Life Cycle Management System (LMS) is a predictive and generic life cycle based management system aimed to support all types of decision making and planning of optimal MR&R activities of any construction works. The system takes into account a number of aspects in sustainable and conscious development such as human requirements, life cycle economy, life cycle ecology and cultural requirements. The LMS is a system by which the complete system or parts thereof, works in co-operation or as a complement to existing business support systems. This imply development and adaptation of the system in order to meet the user needs and requirements, a process which is to be geared and governed by the user. The scope of this paper is focused on development and adaptation of the predictive characteristic of LMS towards a presumptive user. The objective is to develop and adapt a Service Life Performance Analysis (SLPA) module applicable for condition based Facility Management System in general and for condition based Bridge Management System in particular. Emphasis is placed on development and adaptation of a conditional probability based SLPA model in which degradation models and Markov chains play a decisive role. The paper deals also with development and adaptation of environmental exposure data recording and processing, with special emphasis on quantitative environmental classification in order to provide a simplified method of SLPA.

  • 329.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Quantification of exposure classes in The European Standard EN 206-12005Inngår i: 10th International conference on durability of building materials and components: Lyon, France, 17-20 April 2005, 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The recently completed EU-project Life Cycle Management of Concrete Infrastructure for Improved Sustainability (Lifecon) has developed a generic and predictive Life Cycle Management System (LMS) for maintenance optimisation and planning of buildings. The system facilitates the change of today.s reactive practice of maintenance management into a predictive life cycle based maintenance management system. To enable simplified prediction of service life and maintenance interval in such a predictive life cycle management system, a quantitative classification system for environmental loading is needed. At present there are a number of standards containing quantitative classification of environmental loading onto structures and building materials, e.g. ISO 15686-4, EOTA and ISO 9223. The governing standard for concrete structures such as bridges and tunnels is the European Standard EN 206-1 Concrete . part 1: Specification, performance, production and conformity. This standard divides the environmental loading into 18 exposure classes, which cover environmental loads from atmosphere, seawater, fresh water, groundwater and soil, but also the decisive parameters for moisture and chlorides. Almost all exposure classes within the standard include only qualitative descriptions. To make the standard EN 206-1 valid for LMS the standard has to be further developed into a quantitative classification system for environmental loading. A proposal of a quantitative classification of the exposure classes within the standard EN 206-1 regarding corrosion induced by carbonation is presented in this paper. The proposed classification is partly based on the extensive work performed in the Lifecon project, partly based on literature studies. The proposed classification is validated through comparison of real measurements made on a bridge located in Sweden and calculations using a full probabilistic degradation model. It is believed that such exposure classification is possible to use in a LMS to provide simplified service life analysis and possibilities to map the risk of degradation.

  • 330.
    Hallberg, Daniel
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet. KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap.
    System for Predictive Life Cycle Management of Buildings and Infrastructures2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The Life Cycle Management System (LMS) aims at supporting decision-makers and engineers in their efforts to achieve a more optimised proactive life cycle design and maintenance management strategy. LMS is an open and integrative system, which has to be adapted and developed in order to meet the needs and requirements of users. This process should be geared to and governed by the clients. The Architecture, Engineering, Construction and Facility Management (AEC/FM) sector includes all varieties of clients and stakeholders, all of them having different qualifications, possibilities and requirements for implementing, or increasing the feature of predictive maintenance management and optimised proactive strategies. The possibilities of adopting predictive maintenance management are dependent on the availability of performance-over-time and service life forecasting models and methods. The relevance of these models and methods depends on the required level of detailing. Furthermore, the use of the models and methods depends on the availability of reliable input data, such as material data and environmental exposure/in-use condition data. The thesis aims at analysing the possibilities of implementing predictivity in different fields of applications and at evaluating relevant tools facilitating management of information associated with predictive maintenance management systems. The thesis includes studies of three different clients and fields of application; Swedish Road Administration – management of bridges, Locum AB – management of hospital buildings, and Gävle Energi AB – management of district heating distribution systems. While the Swedish Road Administration is responsible to ensure an economically efficient, sustainable transport system for the society throughout the country, Locum AB and Gävle Energi AB compete on an "open" market. The Swedish Road Administration have gathered information about their bridges since 1944, for what reason their bridge management system includes a large amount of valuable data for performance-over- time analyses and service life forecasting. Locum AB has recently begun to systematically gather condition data, why the amount of data is limited. However, since the performance of buildings generally is well known, it is assumed that possibilities of implementing predictive maintenance management tools are rather good. Since district heating pipes are buried into the ground, it is difficult to assess the condition. Therefore, data for service life estimation rely mainly on damage reports. Environmental exposure data on macro or meso level can be obtained from meteorological and environmental institutes, thus making it possible to apply available dose-response and damage functions. Environmental exposure data on a micro level are lacking. Guidelines, methods and tools for environmental measuring and modelling on a micro level are therefore strongly needed. Efficient management of information plays an important role in predictive life cycle management systems. The ongoing development and implementation of open Building Information Model (BIM) tools in the AEC/FM sector is a promising progress of making the information management more cost effective and valuable, especially when open BIM solutions being fully integrated into the AEC/FM business. Geographical Information Systems (GIS) are tools for efficient handling of spatial positioned information. GIS provide possibilities of processing and presenting, e.g., environmental exposure data and environmental risk factors.

  • 331.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Akander, Jan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Stojanovic, Bojan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Kedbäck, Mikael
    Life Cycle Management System: a planning tool supporting Long-term based design and maintenance planning2008Inngår i: Durability of Building Materials & Components 11: Globality and Locality in Durability / [ed] A. Nil Türkeri, Özkan Sengül, Istanbul: Istanbul Technical University , 2008, s. 1871-1878Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Construction projects include large amounts of information that has to be communicated to a number of actors, such as authorities, companies, clients and end users. Information exchange is complex, involving various players on different levels and phases of the construction process. For private clients, who generally have little experience and knowledge of this process, the on-going “Bygga Villa”-project has developed a web-portal, which offers them relevant information about the process and a number of services to facilitate realisation of their projects. One of the services provides a tool for supporting long-term strategy planning. The tool is based on the Life cycle Management System (LMS) that is a predictive and generic life cycle-based management system, aimed to support decision-making and planning of optimal design and maintenance of any construction works. The LMS-Bygga Villa tool estimates service life and maintenance intervals of different building parts and systems based on environmental-dependent degradation models. Simulated scenarios can give optimised solutions by applying life cycle cost analysis. This paper presents two case studies within LMS-Bygga Villa. The first case focuses on service life performance analysis of exterior parts of buildings. The second focuses on service life performance analysis of energy systems; here specifically a borehole assisted heat pump system used for heating a Swedish single-family residence.

  • 332.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Racutanu, George
    Swedish Road Administration, Eskilstuna, Sweden.
    Development of the Swedish bridge management system by introducing a LMS concept2007Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 40, nr 6, s. 627-639Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Swedish Road Administration (SRA) has developed an information technology (IT) based bridge and tunnel management system (BaTMan) that is widely implemented by the organisation. The system is a tool for operational, tactical and strategic management. However, this system does not include systems and tools for managing optimisation and long-term planning of␣Maintenance, Repair and Rehabilitation (MR&R) actions due to service life performance aspects. This paper discusses the need of service life performance analysis for sound optimisation and long-term planning of MR&R actions in the bridge management. The paper presents a service life performance analysis model that is based on a Markov chain model and the MEDIC method. The model is developed to manage different kinds of degradation characteristic and yet present a uniform result expressed in conditional probabilities. The paper discusses also the need of systems and tools for describing objects on both an overall level and on a component level.

  • 333.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Rickard, Bellander
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Beständighet hos trä – utvärdering av långtidsförsök med bullerplank av trä2004Rapport (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Rapporten redovisar resultatet av en långtidsstudie rörande biologisk nedbrytning av ett bullerplank, uppfört 1996, längs Arlandabanan, snabbtågsförbindelsen mellan Stockholms C och Arlanda flygplats. Bullerplanket är till största del byggt av lärkträ men ett antal testsektioner är uppbyggda av andra träslag och behandlade med olika impregneringsmedel. Resultatet från projektet visar att endast de plankor som är i direktkontakt med marken har angripits av röta. De oimpregnerade sektionerna uppvisar högre grad av rötangrepp än de impregnerade furusektionerna. Någon skillnad mellan obehandlad furu och lärk med avseende på rötangrepp har inte gått att finna. En slutsats som kan dras med utgångspunkt från studiens resultat är att impregnerat virke är mycket mer beständigt än obehandlat virke med avseende på rötangrepp. Beständigheten mot biologiska angrepp kommer inte enbart att vara den kritiska faktorn för det studerade bullerplanket. En kombination av de vibrationer och skakningar som uppstår vid förbipasserande tåg kommer att leda till mekanisk nedbrytning av planket. Effekten av den mekaniska nedbrytningen har dock inte undersökts. Även de estetiska faktorerna bör beaktas såsom klotter och klottersanering och hur en eventuell klottersanering kommer att påverka trävirket. För att i framtiden följa nedbrytningen av bullerplanket bör en eventuell uppföljning av projektet göras om 5-10 år. Resultatet kan ses som ett bidrag till framtida forskning inom beständighetsområdet och livslängdbestämning av behandlat och obehandlat trä. Förhoppningen är att resultatet även skall ge en fingervisning om bästa val av material och konstruktionsutformning, för såväl privatpersoner som för projektörer och andra aktörer i byggsektorn.

  • 334.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Sjöström, Christer
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Prediktivt underhåll av fasader2007Inngår i: Bygg & teknik, ISSN 0281-658X, nr 8, s. 46-49Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 335.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Stojanovic, Bojan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Analytical and numerical thermal modelling & analysis of an building integrated unglazed solar collector: PhD course paper2007Inngår i: Mathematics for PhD-students in building science, Stockholm: Architecture and the Built Environment, Royal Institute of Technology , 2007Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The objective of this report is to derive an analytical and numerical USC model for thermal analysis. These models are meant to calculate USC temperature variation across the USC duct as well as the fluid temperature along the USC. The main purpose of the analytical model is to attain a detailed steady state tool for USC (as in this report) design and dimensioning. The numerical model is meant to calculate the time dependant USC thermal performance as well as being a benchmark for the analytical model.

  • 336.
    Hallberg, Daniel
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Stojanovic, Bojan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Akander, Jan
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Långsiktig underhållsplanering av fjärrvärmenät: en förstudie av möjligheter till utveckling av LMS2007Rapport (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Samtidigt som fjärrvärme är ett effektivt sätt att leverera värme så leder en centraliserad värmeproduktion till att fler personer drabbas vid eventuella driftavbrott. Detta skapar ett behov av ökad leveranssäkerhet och kontroll av prestanda över hela fjärrvärmenätets livscykel. Genom en långsiktig planering av nätets utbyggnad och förvaltning erhålls effektivare resursanvändande och större säkerhetsmarginaler. Långsiktig planering bygger till stor del på analys av olika scenarier där såväl rådande förutsättningar som ”worst cases” kan beaktas utifrån olika aspekter (tekniska, ekonomiska, säkerhetsmässiga m.m.). Målet är att hitta optimerade åtgärder, vilket kräver systematisk hantering och bearbetning av en stor mängd information. Detta kan endast göras rationellt med hjälp av IT-verktyg. Life cycle Management System (LMS) är ett resultat av tre konsekutiva EU-finansierade forskningsprojekt där gruppen för byggnadsmaterialteknik – Högskolan i Gävle, har haft en ledande roll. Systemet innehåller utvecklade rutiner och metoder för hantering av information som ligger till grund för långsiktig planering och optimerad förvaltning av byggnadsverk. Systemmässigt är LMS uppbyggt av moduler som hanterar och analyserar data på olika sätt. Anledningen till systemets modulbaserade struktur är att det, helt eller i delar, kan anpassas mot de krav och önskemål som klienten ställer på systemet. På så sätt behöver klienten bara komplettera sitt befintliga system med de funktioner som önskas av LMS, samtidigt som denne undviker att ”kasta ut” det gamla systemet. Förstudien omfattar en litteraturstudie och analys av Gävle Energi AB:s (GEAB) drift- och underhållsdata. Förstudiens syfte är att identifiera och kartlägga de anpassnings- och utvecklingsbehov som föreligger en implementering av LMS som planeringsverktyg för GEAB:s fjärrvärmenät.

  • 337. Hang, Jian
    et al.
    Li, Yuguo
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Understanding Air Exchange and Pollutant Dispersion in a Very Long Street with a RBG k-e Model2006Inngår i: International Conference Megacities 2006, conference proceedings, 2006, s. 442-451Konferansepaper (Annet vitenskapelig)
  • 338.
    Hang, Jian
    et al.
    epartment of Mechanical Engineering, The University of Hong Kong, Hong Kong.
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    LI, Yuguo
    epartment of Mechanical Engineering, The University of Hong Kong, Hong Kong.
    Age of air and air exchange efficiency in idealized city models2009Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 44, nr 8, s. 1714-1723Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wind can provide relevantly clean external (rural) air into urban street network, i.e. city ventilation. The local mean age of air denotes the time it takes for the external air to reach a location after entering the urban canopy layer. The air exchange efficiency denotes the efficiency of flushing the street network with external air. However, difficulties exist in calculating the local mean age of air in a city due to open boundaries. The traditional experimental homogeneous emission method is adapted here in a CFD method to predict the urban local age of air and analyze the air exchange efficiency for city ventilation. Three simple city models are considered, including a round city model, a square city model and a long rectangular city with one main street parallel to the approaching wind or with two crossing streets. The difference in the city shape results in significant difference in the local mean age of air. In the round city of one narrow street, two inflows through street openings converge close to the city centre and exits through the street roof, so the air close to the city centre is relatively old and the air exchange efficiency is low (30%). For a round city with two crossing streets, a slightly non-parallel wind to the main street generates younger air and the higher air exchange efficiency in the city.

  • 339.
    Hang, Jian
    et al.
    Department of Mechanical Engineering, TheUniversity of Hong Kong, Hong Kong SAR, Hong Kong.
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Li, Yuguo
    University of Hong Kong, Hong Kong SAR, Hong Kong.
    Effect of urban morphology on wind condition in idealized city models2009Inngår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, nr 4, s. 869-878Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wind conditions in urban environments are important for a number of reasons. They can serve to transport air pollutants out of the urban environment and to moderate urban microclimatic conditions if satisfactory, yet can compromise pedestrian comfort and safety if not. We aim to study experimentally and numerically the effects of urban morphology (e.g., overall city form (skyline), street orientation, and street configuration) on wind conditions in cities. This report considers our initial investigations of two idealized city forms that are coincidentally similar to ancient Roman cities that were organized on one or two primary streets - a main north-south street, the cardus maximus, and a secondary east-west street, the decumanus maximus - and contained within a well-defined perimeter. We first consider round and square city models with one main street set parallel to the approaching wind and a secondary street producing an intersection at city centre. Not surprisingly, wind conditions in the two city models are dissimilar due to their shape differences. We then consider a long rectangular city model with a fully developed steady flow region along the main street. If the main street of the round city model is narrow, the parallel approaching wind cannot blow through the entire street and a penetrating inflow exists at the leeward opening. For the round city model with two crossing streets, a slightly non-parallel wind to the main street generates a stronger wind level in the entire street volume.

  • 340. Hang, Jian
    et al.
    Sandberg, Mats
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Li, Yuguo Li
    Claesson, Leif
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Pollutant dispersion in idealized city models with different urban morphologies2009Inngår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, nr 38, s. 6011-6025Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanism of pollutant dispersion in idealized city models is investigated numerically by the introduction of a uniformly distributed pollutant source at street pedestrian level. We first study three short city forms with a single main street or two crossing streets, characterized by street length/street height ratios of L/H = 6 or 7 and a street height/street width ratio of H/W = 1, including a sharp-edged round city model, a smooth-edged round city model, and a sharp-edged square city model. For short city models with a single street and a parallel approaching wind, pollutant dilution mainly depends on the horizontal flow rate which decreases along the street. This decreasing rate is smallest for the smooth-edged round city model, which results in the lowest street concentrations. For city models with two crossing streets and the approaching wind parallel to the main street, the differences in overall city form result in different dispersion processes. For a sharp-edged round city model with two crossing streets, an approaching wind slightly non-parallel to the main street generates a lower pollutant concentration in the entire street volume. We also studied a sharp-edged round city model with one narrow street (L/H = 6; H/W = 6.7), finding that the uniformly distributed pollutants are transported from two street entries to the city centre, and are then removed out across the street roof. In contrast to the short city models we studied a single-street sharp-edged long rectangular city model (L/H = 21.7; H/W = 1) in which the horizontal flow rate remained nearly constant in a region far from the two entries. Within this region the turbulence across the street roof contributed more to the pollutant removal than vertical mean flows.

  • 341.
    Hanna, Hanibal
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Konstruktionsförslag på vattensystem till Scanias tillsatsbroms2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Målet med examensarbetet har varit att ta fram ett fungerande förslag på befintligt vattensystem mellan motor och retarder, som är billigt, monteringsbart, har låg vikt och lång livslängd i fordon. Retarder är en hjälpbroms och har som främsta uppgift att minska slitage på de ordinarie bromsarna.

    För att lösa detta gjordes först en nulägesbeskrivning där kylvattenröret kartlades. Därefter intervjuades Scania personalen på Retarder och det resonerades kring tidigare konstruktioner gjorda på området.

    De teorier som användes var monteringsanpassad konstruktion (DFA), tillverkningsanpassad konstruktion (DFM), miljöanpassad konstruktion (DFE), feleffektanalys (FMEA) och Scania produktions system (SPS).

    För att säkerställa vilken typ av material och tillverkningsmetod som ska användas i konstruktionen gjordes ett "out of the box" tänkande. Informationen som framkom pekade på att dimensionen borde optimeras, det betydliga materialet ändras och att fästena på kylvattenröret borde elimineras. Detta för att erhåll en billigare, lättare och mer monteringsvänligare konstruktion.

    Konstruktionsförslaget är ett kylvattenrör med fästen som är av bockad plåt och som monteras på gummirör för att dämpa vibrationerna. Här har jag ersatt de svetsade fästena med monterbara fästen som håller kylvattenröret på plats. Vidare har godstjockleken på kylvattenröret optimerats från 2 mm till 1,5 mm och jag har behållit det befintliga materialet SS-EN 1010216, tryckkärlsstål, då både aluminium och plast inte höll vid de vibrationer som uppkom i fordonet. Dessutom har fästena, som håller upp hela konstruktionen av kylvattenröret mot växellådan, omkonstruerats så att det passar det nya konstruktionen. Dessa fästen monteras på växelhuset med två stycken M10 skruvar i varje fäste.

    Simuleringar med finita elementmetoden (FEM) genomfördes för att undersöka deformationer och spänningar som uppstod när kylvätskan passerade genom kylvattenröret och då vibrationer uppstod från motorn, pumpen, hjulen eller vägunderlagen. Resultat från analyser med FEM tydde på att de största påkänningarna fanns på de rundfästen som håller upp kylvattenröret. Den högsta statiska spänningen på dessa fästen är 75 MPa med en sträckgräns på 500MPa. Denna anses vara låg och betraktas inte som kritisk.

    Vid den dynamiska analysen resulterade detta i att egenfrekvens uppkom vid 162 Hz som är över Scanias kritiska intervall, 150 Hz. För att säkerställa att konstruktionen är hållbar bör en prototyp tillverkas och testas.

    Förslaget presenterades för både chefen och montörerna på monteringsområdet och de var positiv inställda till förslaget av en rad olika anledningar så som lättare montering, kortare monteringstider, ergonomisk montering, kvalitetssäkrad montering samt förmonteringsbar. Dessutom kan bemanningen minimeras till följd av de korta monteringstiderna.

  • 342.
    Hansson, Niklas
    Högskolan i Gävle, Institutionen för teknik och byggd miljö. Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Samband vid Brf. Krönet: studier runt en väderstation2009Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med detta examensarbete är att titta på och eventuellt upptäcka vissa samband mellan de vanligaste klimatparametrarna (lufttemperatur, sol, vind, luftfuktighet och lufttryck) och inomhusklimatet. Inomhusklimatet är i detta arbete det samma som luftens temperatur inomhus.

    Även en sammanställning av två studier kring NordIQ’s styrning av värmesystemet och tappvarmvattnet görs.

     

    En stor del av arbetet har varit att sammanställa och studera insamlad data från bland annat en väderstation.

    Under den här perioden (våren) är det solen och utomhustemperaturen som har störst påverkan på temperaturen inomhus.

     

    En stor del inom energisektorn idag handlar om att använda energin effektivare och minska på utsläppen. Förhoppningen är att detta arbete ska kunna hjälpa till i den riktningen. Att utnyttja gratisenergin och dra ner på t.ex. fjärrvärmen är ett sätt, att inte kyla bort övertemperaturer utan att istället dra ner på den köpta energin.

     

    Ett annat sätt att utnyttja energin på ett effektivare sätt är att öka avkylningen och minska på flödet i uppvärmningssystemet. Det är något som NordIQ säger sig göra med sin styrning av värme och tappvarmvatten.

    Sammanställningen visar att det stämmer.

  • 343.
    Hansson, Peter
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Björling, Mikael
    Högskolan i Gävle, Institutionen för matematik, natur- och datavetenskap, Ämnesavdelningen för naturvetenskap.
    Stymne, Hans
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Permeation of the tracer gas SF6 through three common building materials with and without surface treatment2004Inngår i: Proceedings of Roomvent 2004: 9th International Conference on Air Distribution in Rooms, Coimbra, Portugal, 2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Tracer gas sorption in and permeation through building materials influence tracer gas ventilation measurements. The permeation of the commonly used tracer SF6 through three different building materials (gypsum board, wood particle board and MDF-board) with and without paint has been experimentally investigated. The results show that the tracer diffuse through untreated boards and that gypsum board has the largest permeability towards SF6. However, the diffusion rate of tracer is effectively reduced when the boards are coated with two layers of latex paint. Caution should therefore be exercised when using tracer gas measurements in rooms with walls of untreated porous materials.

  • 344. Havenith, George
    et al.
    Nilsson, Håkan O.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
    Correction of clothing insulation for movement and wind effects, a meta-analysis2004Inngår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 92, nr 6, s. 636-640Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A meta-analysis of the effect of body and air movement on the insulation provided by workwear and cold-weather clothing [1.22 clo (0.189 m 2 °C W –1) <I T<4.14 clo (0.642 m 2 °C W –1)] using data from different sources was performed. For the effect of walking, datasets could be merged and a single prediction equation produced (r 2=0.91). For the effect of wind, and interaction of movement and wind, separate equations were required for regular workwear (r 2=0.93) and cold-weather clothing (r 2=0.97). Differences were mainly due to the different amounts of nude surface area. An interaction between wind and walking effects was present (the size of the combined effects is less than the sum of the separate effects), and for cold-weather clothing an effect of clothing air permeability (p) was present (high pbigger effect). The resulting prediction equations will be proposed for inclusion in European and ISO standards on protective clothing to assist the user in determining the real-life clothing insulation value.

  • 345.
    He, Qiao
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Trading Oil Futures2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Oil is an important energy source and a necessary industrial raw material. Every country’s economic growth and the daily life of its people are dependent on this energy form.

    Historically, the oil prices have varied significantly on the world market. This led to at least two oil crises when prices increased in a very fast pace. In order to reduce such rapid fluctuations, oil was introduced at so called commodity exchanges. At such trading places oil could be traded openly for future delivery and hence the market was aware of price changes in advance. A commodity exchange sells special contracts in the form of so called “futures”. In fact there are many different contracts, each exchange has its own set of them covering for a number of different oil types. This thesis deals with these contracts and how they are traded.

  • 346.
    HE, Xin
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för samhällsbyggnad.
    Modeling church services supply and performance, using geographically weighted regression2009Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The objective of this study is to develop a multiple linear regression model that measures the relationship between the church services supply and the attendance to the services in the Uppsala diocese, Church of Sweden. By reviewing previous models and examining the nature of data available, two research questions were introduced, namely, the problem of omitted variables and the problem of spatial autocorrelation. For the first question, two methods were compared, namely, the Y-lag method and the first-differenced equation. Statistical tests then showed that the latter was more preferable for this study. For the second question, geographically weighted regression was used to examine the spatial variations in relationships estimated by above modeling strategies. However, no significant spatial variation was found for them. In conclusion, by using the ordinary least square estimation for the first-differenced equation the most suitable regression model was obtained. The data showed no need to consider the issue of spatial non-stationarity.

  • 347.
    Hed, Göran
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Service Life Estimations in the Design of a PCM Based Night Cooling System2005Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The use of Phase Change Material, PCM, to change the thermal inertia of lightweight buildings is investigated in the CRAFT project C-TIDE. It is a joint project with Italian and Swedish partners, representing both industry and research. PCMs are materials where the phase change enthalpy can be used for thermal storage. The Swedish application is a night ventilation system where cold night air is used to solidify the PCM. The PCM is melted in the day with warm indoor air and thereby the indoor air is cooled. The system is intended for light weight buildings with an overproduction of heat during daytime. In the thesis, the results of experiments and numerical simulations of the application are presented. The theoretical background in order design the heat exchanger and applying the installation in thermal simulation software is presented. An extensive program is set up, in order to develop test methods and carry tests to evaluate the performance over time of the PCM. Testing procedures are set up according to ISO standards concerning service life testing. The tests are focused on the change over time of the Thermal Storage Capacity (TSC) in different temperature spans. Measurements are carried out on large samples with a water bath calorimeter. The service life estimation of a material is based on the performance of one or more critical properties over time. When the performances of these properties are below the performance requirements, the material has reached its service life. The critical properties of the PCM are evaluated by simulation of the application. The performance requirements of the material are set up according to general requirements of PCM and requirements according to building legislation. The critical properties of a PCM are the transition temperature, the melting temperature range and the TSC in the operative temperature interval. The critical property of the application is its energy efficiency.

    The results of the study show that the night cooling system will lower the indoor air temperature during daytime. It also shows that the tested PCM does not have a clear phase change, but an increased specific heat in the operative temperature interval. Increasing the amount of material, used in the application, can compensate this. Finally, the tested PCM is thermally stable and the service life of the product is within the range of the design lives of the building services. It is essential to for all designers to know the performance over time of the properties of PCMs. Therefore it is desirable that standardized testing methods of PCM are established and standardized classification systems of PCMs are developed.

  • 348.
    Hed, Göran
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för byggnadskvalitet.
    Service Life Planning in Building Design2000Rapport (Annet vitenskapelig)
  • 349.
    Hed, Göran
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Bellander, R
    Mathematical modelling of PCM air heat exchanger2006Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 38, nr 2, s. 82-89Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to cool a room with a cold night air phase change material, PCM, is stored in an air heat exchanger. During night the PCM crystallises, energy is released. During daytime air is circulated in the unit, energy is absorbed and the indoor air is cooled. The characteristic of PCM is that there is an increase of the specific heat over a limited temperature span. This is the principle that is used in the design of the PCM air heat exchanger unit. The action of a PCM storage unit will act differently depending of the thermal properties of the material. In an ideal material the phase transition occurs at a given temperature. On the market, compounds containing PCM are available which, in order to create a suitable melting temperature, are mixtures of different products. In these materials, the transition from liquid to solid takes place over a temperature span, i.e. the specific heat varies with the temperature. This can be represented by a c(p)(T) curve, specific heat as a function of the temperature. In this paper, the development of a mathematical model of the PCM air heat exchanger is presented. Considerations are taken to different shapes of the cp(T) curve. The mathematical model is verified with measurement on a prototype heat exchanger. The development of the equipment is part of the CRAFT project Changeable Thermal Inertia Dry Enclosures (C-TIDE) the possibility of use of phase change materials integrated into a building is explored. 

  • 350.
    Hedefalk, Finn
    Högskolan i Gävle, Institutionen för teknik och byggd miljö.
    Robustness of Spatial Databases: Using Network Analysis on GIS Data Models2010Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Demands on the quality and reliability of Volunteered Geographic Information have increased because of its rising popularity. Due to the less controlled data entry, there is a risk that people provide false or inaccurate information to the database. One factor that affects the effect of such updates is the network structure of the database schema, which might reveal the database’s robustness against different kinds of false updates. Therefore, network analyses are needed. The aim is to analyse GIS data models, stored in UML class diagrams, for scale-free and small-world properties. Moreover, a robustness analysis is to be carried out on selected data models in order to find out their error and attack tolerance against, for example, false updates. Three graphs were specified from the UML class diagrams: (1) class graphs: classes as nodes and their interactive relationships as connections; (2) attribute graphs: classes and attributes as nodes, with connections between the classes and their attributes; and (3) schema graphs: attributes as nodes and their interactive relationships inside and outside the tables as links. The analysed class diagrams were stored in XMI, and therefore transformed with XSLT to the Pajek network format. Thereafter, small-world and scale-free analyses as well as a robustness analysis were performed on the graphs. 

    The results from the scale-free analyses showed no strict power-laws. Nevertheless, the classes’ relationships and attributes, and the betweenness in the schema graphs were long-tailed distributed. Furthermore, the schema graphs had small-world properties, and the analysed class and schema graphs were robust against errors but fragile against attacks. In a network structure perspective, these results indicate that false updates on random tables of a database should usually do little harm, but falsely updating the most central cells or tables may cause big damage. Consequently, it may be necessary to monitor and constrain sensitive cells and tables in order to protect them from attacks

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