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Luleå tekniska universitet Övrigt
N/A / Link / Lindberg , Malin / 2004

Luleå tekniska universitet Övrigt
N/A / Link / Kristoffersson , Maria / 2003

Algorithms for fitting a surface, explicitly or implicitly defined, to some measured points are developed, analyzed and tested. The problem class treated, includes orthogonal regression and errors-in-variables. Methods using only first order derivatives as well as second order methods are developed and the rich inherent structure of the problem is fully utilized. The main features of the algorithms, that distinguish them from earlier works, are that arbitrary nonnegative weights can be handled and that infinite weights can be used to define nonlinear equality constraints. Moreover, by using a special merit function, global convergence can be proved for the first order methods under some nondegeneracy assumptions. The local convergence for the first order algorithms is linear for nonzero residual problems and quadratic otherwise. The local convergence for the second order methods is quadratic. A mixed algorithm where only a part of the second derivatives are included is also developed and tested.
N/A / Link / Gulliksson , Mårten / 1995

Luleå tekniska universitet Övrigt
The problem of computing a least squares spline using Kalman filter algorithms is considered. An appropriate stochastic setting is identified and a new efficient algorithm, based on techniques for weighted and constrained linear least squares, is presented. Numerical examples illustrating good numerical properties of the new algorithm are given.
N/A / Link / Söderkvist , Inge / 1995

Luleå tekniska universitet Övrigt
E-procurement is constantly receiving attention from industries, business and government agencies. Analysts believe that utilization of e-procurement can lead to enormous cost saving and efficiency in procurement process. E-procurement also enlarges customer base, broadens the search for raw materials to lower its production cost. Though, it has benefited the global business tremendously, its expected growth rate has been moving downwards. While E-procurement can be used for the purchase of indirect or direct materials, the risks associated with the e-procurement has been holding the companies from adopting it. The purpose of this paper is to understand the e-procurement process by focusing on benefits, risks, practices and strategies of e-procurement and its emerging usages in the current business to business (B2B) environment. A qualitative method was used for the case studies in which two companies each from India and Sweden were studied and analysed. The results showed that cost benefit was the main driver for companies to implement e-procurement. Other benefits included were transparency and visibility across process, better internal and external relations and streamlined buying process. The problems of implementation and integration of existing infrastructure and security and control risks were holding back companies from wide usage of e-procurement. But most of all, lack of managerial commitment hinders the adoption process. Company's needs were the deciding factor for the kind of approach they will follow regarding the adoption of e-procurement and emergence of a new approach. This paper compares the works of different authors in the field of e-procurement and its implications for the B2B.
952-15-1678-X / Link / Parida , Vinit / 2006

Luleå tekniska universitet Övrigt
N/A / Link / Lindberg , Malin / 2003

Luleå tekniska universitet Övrigt
91-7656-624-2 / Link / Westring-Nordh , Marianne / 2006

The invention relates to a method for determining a measure for evaluation of the behaviour of a driver of a vehicle comprising: determining the lateral position of the vehicle in relation to a lane and the state of the vehicle at a first instant (t1), determining the planned path which the vehicle would be expected follow from said first instant t1 considering the state of the vehicle at said first instant (t1), determining the planned lateral position of the vehicle in relation to a lane at a second instant (t2) being a time interval ( t PD ) after t1, if said planned path were followed, and determining a planned deviation being the difference between the planned lateral position at the second instant (t2) with the lateral position at the first instant (t1).
N/A / Link / Birk , Wolfgang / 2006

Prefabricerade betongbalkar har studerats i fältmätningar och teoretiska beräkningar avseende temperatursprickor under härdningsförloppet vid användande av cement P400. Speciellt  intressant har varit att se hur temperaturer och sprickrisker varierat under den närmaste tiden efter gjutningen då balkarna härdat i gjuthall och sedan transporterats ut i kall utomhusluft. Arbetet kopplas till tidigare utförda materialprovningar på betong med P400 cement och till beräkningar där sprickrisker för några typfall  har tagits fram. Arbete avser att leda fram till riktlinjer om hur prefabricerade element skall hanteras för att uppfylla krav  på spricksäkerhet enligt Vägverkets rekommendationer i Bro 94. I fältmätningarna har risken för ytsprickor studerats vid gjutning av en balktyp av dimension 1200 ´ 850 mm. Betong med cement P400 och vct = 0.37 har använts. Sex balkar har gjutits i två omgångar. Längd på lagringstid i gjuthall samt för hållande vid lagring utomhus har varierats. Uppföljande beräkningar har utförts med datorprogrammen HETT2D och TEMPSTRE-N. Både fältmätningarna och uppföljande beräkningar visar att acceptabel låg ytsprickrisk kan erhållas för denna balktyp om den inte utsätts för temperaturchock vid låg utomhus temperatur och vid hög vindhastighet. Det är en mycket tidig (15 - 25 h efter gjutning) uttransport av balk som är kritisk i detta fall. Studien visar också att det är, om än med viss möda, möjligt att simulera verkliga härdningsförhållanden med beräkningsprogrammen. Under det första dygnet efter gjutningen är nämligen erhållna temperaturnivåer mycket starkt beroende av noggrannhet hos använda materialdata, isoleringsförhållanden och väderleksbetingelser. Med standardindata till beräkningsprogrammen tendera avsvalningen att bli för snabb ledande till för höga teoretiska spänningsnivåer. Med anpassade randvillkor är det möjligt att uppnå hög träffsäkerhet i analyserna. Tillsammans med övriga rapporter om temperatursprickrisk kan resultatet tjäna som underlag för rekommendationer för sprickfri prefabricering av betongbalkar kunna utarbetas.
N/A / Link / Thun , Håkan / 1997

Luleå tekniska universitet Övrigt
N/A / Link / Vikström , Anna / 2006

Luleå tekniska universitet Övrigt
Principal Topic Innovation goes hand in hand with creativity and freedom. Yet, with separation of ownership and governance, too much freedom might invoke a host of issues associated with the agency problem. Monitoring has been cited as one of the universal cures against agency-related issues. Though effective in most cases, whether or not (and to what extent) monitoring is beneficial when tasks in question are highly innovative remains under-researched. We explore relationships between monitoring and innovative performance in the context of Swedish strategic small- and medium-size networks (SME networks). Strategic SME networks consist of geographically proximate independent but related small- and medium-sized firms that cooperate to improve their innovative stature by means of multilateral intra-network technology and know-how exchange. As the degree of intra-network cooperation differs between the membership firms, and there is a possibility for free-riding, the networks often establish boards responsible for monitoring network innovative activities. Effects of such monitoring are the main focus of our study. Method To tackle the questions posed by the study, we used five-year panel data on 53 Swedish networks collected through extensive telephone interviews and questionnaires from network representatives and policy makers responsible for the network support throughout the country. Both linear and non-linear effects were examined. Given the nature of our data, we employed a within estimator with first-order autoregressive disturbance term as suggested by the appropriate econometric tests. Results and Implications Our results indicate that having board members compensation determined by the outcomes of the innovative activities of the member firms significantly improves network innovative performance. At the same time, relationships between network board independence and size, and innovation performance are more complex. While remaining positive, effect of the network board size on innovative performance diminishes. Effect of the board independence, on the other hand, remains positive only up to a certain threshold beyond which board independence actually hampers network innovative performance. Our findings help resolve some of the controversies reported by the previous literature, suggest several areas for future work on network board composition in strategic SME networks context, and contribute to entrepreneurship, agency, and networks literatures.
N/A / Link / Wincent , Joakim / 2006

Luleå tekniska universitet Övrigt
91-631-2507-2 / Link / Westring-Nordh , Marianne / 2002

Luleå tekniska universitet Övrigt
N/A / Link / Westring-Nordh , Marianne / 2006

Luleå tekniska universitet Övrigt
N/A / Link / Burman , Lena / 2004

This research tests a model including direct and indirect effects of CEO's personal traits (i.e., tolerance for ambiguity and self-efficacy) on entrepreneurial behavior for firms in a specific context, namely strategic SME networks. Findings indicate no direct relationship between personal traits and entrepreneurial behavior on the firm level but reports positive relationship between CEO's traits and levels of inter-firm networking with other strategic SME network participants. Inter-firm networking, in turn, is positively related to entrepreneurial behavior on the firm level. Our results thus indicate that personal traits of the CEO can be important to study in order to understand small firm behavior and performance. The absence of direct links may hide interesting indirect and mediating influences. Based on this, we argue that it is important for future research in the entrepreneurship domain to consider inclusion of context-specific action-based factors that may link CEO traits to entrepreneurship.
N/A / Link / Wincent , Joakim / 2005

Luleå tekniska universitet Övrigt
N/A / Link / Annerborn , Kent / 2005

N/A / Link / Ylinenpää , Håkan / 2003

Luleå tekniska universitet Övrigt
Vi står inför stora utmaningar ifråga om energi, miljö och klimat och en resa till Kina understryker detta. Kina låg en gång långt före övriga länder men föll sedan tillbaka under flera hundra år för att nu återigen utvecklas mycket kraftigt. - Orsaker till dagens framgångar i Kina och i västerlandet - Viktiga faktorer för att få ett lyckligt liv? - Tack till de som hjälpt att planera och genomföra en Kinaresa i april 2007
N/A / Link / Elfgren , Lennart / 2007

Luleå tekniska universitet Övrigt
N/A / Link / Udén , Maria / 1995

Luleå tekniska universitet Övrigt
Monitoring of several railway bridges has been carried out in northern Sweden in order to increase the allowable axle load. The work is part of a European Integrated Project "Sustainable Bridges - Assessment for Future Traffic Demands and Longer Lives". The paper describes the project and gives some examples of applications.
978-91-633-0607-5 / Link / Elfgren , Lennart / 2007

Luleå tekniska universitet Övrigt
Evaluation of Spherical Fitting as a technique for sizing iron ore pellets is performed. Size measurement of pellet in industry is usually performed by manual sampling and sieving techniques. Automatic on-line analysis of pellet size would allow non-invasive, frequent and consistent measurement. Previous work has used an assumption that pellets are spherical to estimate pellet sizes. In this research we use a 3D laser camera system in a laboratory environment to capture 3D surface data of pellets and steel balls. Validation of the 3D data against a spherical model has been performed and demonstrates that pellets are not spherical and have physical structures that a spherical model cannot capture.
1-4244-0588-2 / Link / Andersson , Tobias / 2007

N/A / Link / Ohlsson , Johan / 2005

Assessment of the spatial quality of reproduced sound is becoming more important as the number of techniques and systems affecting such quality increases. The presence of dimensions forming spatial quality has been indicated in earlier experiments by using attributes as descriptors for the dimensions. These attributes have been found relevant for describing the spatial quality of stimuli subjected to different modes of reproduction. In this paper, new attributes are elicited and the applicability of these and previously encountered attributes for assessment of spatial quality is tested in the context of new stimuli, recorded by means of 5-channel microphone techniques and reproduced through a 5.0 system.
N/A / Link / Berg , Jan / 2002

Syftet med projektet var för det första att undersöka hur anbudsgivare och potentiella sådana ser på Vägverkets upphandlings- och konkurrensutsättningsstrategi. (Hur bör en modell se ut som verkligen skulle intressera anbudsgivarna?) För det andra ingick att analysera svaren från anbudsgivarna i samverkan med personer (med upphandlingskompetens) vid Vägverket och med utgångspunkt från denna dialog föreslå en ny upphandlings- och konkurrensutsättningsstrategi. Analysen av svaren gav att fyra skilda delmarknader kan identifieras. Norr- och västerbottens kustland inklusive kustnära kommuner typ Vännäs och Boden Gränskommuner mot Finland Städer i Norrlands inland (Lycksele, Gällivare och Kiruna) Norrlands inland (exklusive städer) Utmärkande för konkurrensen i respektive område är att; i område ett förväntas konkurrensen kunna upprätthållas med nuvarande upphandlingsstrategi. i område två ökar konkurrensen pga. de finska åkarna som kan gå in med låga timpriser. i område tre medför gruvverksamheten i Kiruna och Gällivare att de stora anläggningsbyggarna är aktiva i området vilket upprätthåller en viss konkurrens. I område fyra (och eventuellt tre) kommer troligen en kraftigt minskad konkurrens att inträffa de närmaste åren och särskilt om nuvarande upphandlingsstrategi bibehålles. Seminariet och den efterföljande analysen resulterade i ett förslag till ny upphandlings- och konkurrensutsättningsstrategi vilken behandlar följande rubriker; Marknad Kundfokus Riskfördelning Utveckling Kalkylerbarhet Ekonomiska drivkrafter
N/A / Link / Johansson , Pär / 2000

Luleå tekniska universitet Övrigt
N/A / Link / Drnovsek , M. / 2004

Luleå tekniska universitet Övrigt
N/A / Link / Maligranda , Lech / 2006

Luleå tekniska universitet Övrigt
N/A / Link / Maligranda , Lech / 2006

Luleå tekniska universitet Övrigt
Some numerical methods for calculating the rotation of a sphere with a dot pattern are studied. The moving sphere has been video recorded and the coordinates of the moving dots have been determined with the aid of image analysis. It turns out that a method that uses a least squares technique to compute the rotation matrix of the rotation is least sensitive to discretisation errors, but more traditionally methods, that use vector cross products, are more computationally efficient when less than five dots are available. 1 This work was supported by Norrbottens Forskningsrad, Lulea, Sweden 1 Introduction The movement of particles can be described as the sums of translations and a rotations. In experimental verification of mathematical models of granular flows it is therefore of importance to measure not only translation but also rotation. Such measurements are rare, however, and mostly deal with the rotation of a single or very few particles [2, 9]. This is easily explained by the com...
N/A / Link / Söderkvist , Inge / 1994