| 1. |
- Andersson, Arne, et al.
(author)
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Integer Programming for Combinatorial Auction Winner Determination.
- 2000
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In: Proc. of the Fourth International Conference on Multiagent Systems (ICMAS-00).
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Conference paper (peer-reviewed)abstract
- Combinatorial auctions are important as they enable bidders to place bids on combinations of items; compared to other auction mechanisms, they often increase the efficiency of the auction, while keeping risks for bidders low. However, the determination of an optimal winner combination in combinatorial auctions is a complex computational problem.In this paper we (i) compare recent algorithms for winner determination to traditional algorithms, (ii) present and benchmark a mixed integer progra mming approach to the problem, which enables very general auctions to be treated efficiently by standard integer programming algorithms (and hereby also by commercially available software), and (iii) discuss the impact of the probability distributions chosen for benchmarking.
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| 2. |
- Andersson, Anna, et al.
(author)
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Paired multiplex reverse-transcriptase polymerase chain reaction (PMRT-PCR) analysis as a rapid and accurate diagnostic tool for the detection of MLL fusion genes in hematologic malignancies
- 2001
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In: Leukemia. - 1476-5551. ; 15:8, s. 1293-1293
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Journal article (peer-reviewed)abstract
- The MLL gene in chromosome band 11q23 is frequently rearranged in acute lymphoblastic and acute myeloid leukemias. To date, more than 50 different chromosomal regions are known to participate in translocations involving 11q23, many of which affect MLL. The pathogenetically important outcome of these rearrangements is most likely the creation of a fusion gene consisting of the 5' part of the MLL gene and the 3' end of the partner gene. Although abnormalities of the MLL gene as such are generally associated with poor survival, recent data suggest that the prognostic impact varies among the different fusion genes generated. Hence, detection of the specific chimeric gene produced is important for proper prognostication and clinical decision making. We have developed a paired multiplex reverse-transcriptase polymerase chain reaction analysis to facilitate a rapid and accurate detection of the most frequent MLL fusion genes in adult and childhood acute leukemias. To increase the specificity, two sets of primers were designed for each fusion gene, and these paired primer sets were run in parallel in two separate multiplex one-step PCR reactions. Using the described protocol, we were able to amplify successfully, in one single assay, the six clinically relevant fusion genes generated by the t(4;11)(q21;q23) [MLL/AF4], t(6;11)(q27;q23) [MLL/AF6], t(9;11)(p21-22;q23) [MLL/AF9], t(10;11)(p11-13;q23) [MLL/AF10], t(11;19)(q23;p13.1) [MLL/ELL], and t(11;19)(q23; p13.3) [MLL/ENL] in cell lines, as well as in patient material.
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| 3. |
- Andersson, Lars Mattias, 1976-
(author)
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Topics in color measurement
- 2004
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Licentiate thesis (other academic/artistic)abstract
- Color characterizations of printing situations are essential for a correct color reproduction. To obtain a good color characterization, knowledge about the substrate, the printing process and the printer function are all of great importance. In this thesis, methods for color characterization of printing situations are proposed and the problems associated with the transfer of color characterization methods from spectrophotometers to flatbed scanners are extensively studied. All methods have been developed with bearing on digital printing technologies, although they can be applied to any printing system. Special emphasis has been put on the influence of paper properties in printing situations and image capturing of printed substrates.
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| 4. |
- Andersson, Mattias, et al.
(author)
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Approximate distance oracles for graphs with dense clusters
- 2004
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In: Algorithms and Computation / Lecture notes in computer science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. ; 3341, s. 53-64
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Conference paper (peer-reviewed)abstract
- Let H-1 = (V, F-1) be a collection of N pairwise vertex disjoint O(1)-spanners where the weight of an edge is equal to the Euclidean distance between its endpoints. Let H-2 = (V, F-2) be a graph on V with M edges of non-negative weight. The union of the two graphs is denoted G = (V, F-1 boolean OR F-2). We present a data structure of size O(M-2 + V log V) that answers (1 + epsilon)-approximate shortest path queries in G in constant time, where epsilon > 0 is constant.
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| 5. |
- Andersson, Mattias, et al.
(author)
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Balanced partition of minimum spanning trees
- 2003
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In: International Journal of Computational Geometry and Applications. - 0218-1959. ; 13:4, s. 303-316
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Journal article (peer-reviewed)abstract
- To better handle situations where additional resources are available to carry out a task, many problems from the manufacturing industry involve dividing a task into a number of smaller tasks, while optimizing a specific objective function. In this paper we consider the problem of partitioning a given set S of n points in the plane into k subsets, S-1,...,S-k, such that max(1less than or equal toiless than or equal tok) MST(S-i) is minimized. Variants of this problem arise in applications from the shipbuilding industry. We show that this problem is NP-hard, and we also present an approximation algorithm for the problem, in the case when k is a fixed constant. The approximation algorithm runs in time O(n logn) and produces a partition that is within a factor (4/3 + epsilon) of the optimal if k = 2, and a factor (2 + epsilon) otherwise.
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| 6. |
- Andersson, Mattias, et al.
(author)
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Balanced Partition of Minimum Spanning Trees
- 2002
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In: Computational Science — ICCS 2002 / Lecture notes in computer science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. ; 2331, s. 26-35
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Conference paper (peer-reviewed)abstract
- To better handle situations where additional resources are available to carry out a task, many problems from the manufacturing industry involve "optimally" dividing a task into k smaller tasks. We consider the problem of partitioning a given set S of n points (in the plane) into k subsets, S1,...,Sk that max 1leqslant i leqslant k |MST(Si) | is minimized. A variant of this problem arises in the shipbuilding industry [2].
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| 7. |
- Andersson, Mattias, et al.
(author)
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Chips on wafers
- 2003
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In: Algorithms and data structures. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540405450 ; 2748, s. 412-423
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Conference paper (peer-reviewed)abstract
- A set of rectangles S is said to be grid packed if there exists a rectangular grid (not necessarily regular) such that every rectangle lies in the grid and there is at most one rectangle of S in each cell. The area of a grid packing is the area of a minimal bounding box that contains all the rectangles in the grid packing. We present an approximation algorithm that given a set S of rectangles and a real constant epsilon > 0 produces a grid packing of S whose area is at most (I + epsilon) times larger than an optimal packing in polynomial time. If epsilon is chosen large enough the running time of the algorithm will be linear. We also study several interesting variants, for example the smallest area grid packing containing at least k less than or equal to n rectangles, and given a region A grid pack as many rectangles as possible within A. Apart from the approximation algorithms we present several hardness results.
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| 8. |
- Andersson, Mike, et al.
(author)
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Investigations on the possibilities of a MISiCFET sensor system for OBD and combustion control utilizing different catalytic gate materials
- 2004
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In: Topics in catalysis. - 1022-5528 .- 1572-9028. ; 30-31:1, s. 365-368
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Journal article (peer-reviewed)abstract
- Different catalytic materials, like Pt and Ir, applied as gate contacts on metal insulator silicon carbide field effect transistors — MISiCFET—facilitate the manufacture of gas sensor devices with differences in selectivity, devices which due to the chemical stability and wide band gap of SiC are suitable for high temperature applications. The combination of such devices in a sensor system, utilizing multivariate analysis/modeling, have been tested and some promising results in respect of monitoring a few typical exhaust and flue gas constituents, in the future aiming at on board diagnostics (OBD) and combustion control, have been obtained.
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| 9. |
- Andersson, Per, 1964-, et al.
(author)
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Vägvisaren
- 2003
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Other publication (pop. science, debate, etc.)
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Björnsson, Jon Mar, et al.
(author)
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Reduced proliferative capacity of hematopoietic stem cells deficient in hoxb3 and hoxb4
- 2003
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In: Blood. - 0006-4971 .- 1528-0020. ; 23:11, s. 3872-3883
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Journal article (peer-reviewed)abstract
- Several homeobox transcription factors, such as HOXB3 and HOXB4, have been implicated in regulation of hematopoiesis. In support of this, studies show that overexpression of HOXB4 strongly enhances hematopoietic stem cell regeneration. Here we find that mice deficient in both Hoxb3 and Hoxb4 have defects in endogenous hematopoiesis with reduced cellularity in hematopoietic organs and diminished number of hematopoietic progenitors without perturbing lineage commitment. Analysis of embryonic day 14.5 fetal livers revealed a significant reduction in the hematopoietic stem cell pool, suggesting that the reduction in cellularity observed postnatally is due to insufficient expansion during fetal development. Primitive Lin(-) Scal(+) c-kit(+) hematopoietic progenitors lacking Hoxb3 and Hoxb4 displayed impaired proliferative capacity in vitro. Similarly, in vivo repopulating studies of Hoxb3/Hoxb4-deficient hematopoietic cells resulted in lower repopulating capability compared to normal littermates. Since no defects in homing were observed, these results suggest a slower regeneration of mutant HSC. Furthermore, treatment with cytostatic drugs demonstrated slower cell cycle kinetics of hematopoietic stem cells deficient in Hoxb3 and Hoxb4, resulting in increased tolerance to antimitotic drugs. Collectively, these data suggest a direct physiological role of Hoxb4 and Hoxb3 in regulating stem cell regeneration and that these genes are required for maximal proliferative response.
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| 15. |
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| 16. |
- Ekberg, Christian, 1967, et al.
(author)
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Uses of pH Electrodes in Nuclear Chemistry
- 2002
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In: Analytical and Bioanalytical Chemistry. - 1618-2642 .- 1618-2650. ; 374:5, s. 824-830
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Journal article (peer-reviewed)abstract
- The determination and definition of pH is a controversial subject in many areas in chemistry. For these reasons the International Union of Pure and Applied Chemistry (IUPAC) has developed recommendations for pH measurement. These recommendations are currently (winter 2001) under revision - there will be increased emphasis on traceability of uncertainties in pH measurement. Here we describe how glass electrodes designed for measurement of pH are used in nuclear chemistry. The use of pH electrodes is then related to the IUPAC recommendations. In applied chemistry, e.g. nuclear chemistry, a pH is not sought as often as a hydrogen ion concentration or a simple equilibrium point during a titration. Ionic strengths are, moreover, often above the range in which the IUPAC recommendations apply. In these instances uncertainties must be assessed individually.
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| 17. |
- Gadisa, Abay, et al.
(author)
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Correlation between oxidation potential and open-circuit voltage of composite solar cells based on blends of polythiophenes/fullerene derivative
- 2004
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 84:9, s. 1609-1611
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Journal article (peer-reviewed)abstract
- The photovoltaic parameters of donor/acceptor blend organic solar cells are highly influenced by several parameters, such as the strength of the acceptor species, the morphology of the film due to the solvent, and the mobility of the free charge carriers. In this work, the open-circuit voltage (Voc) of solar cells based on series of conjugated polythiophene polymers were measured and compared. In every cell, the donor polymer was blended with an electron acceptor fullerene molecule. The devices were constructed in a sandwich structure with indium tin oxide (ITO)/metallic polymer (PEDOT:PSS) acting as an anode and Al or LiF/Al acting as a cathode. Comparing the Voc of all the cells shows that this important photovoltaic parameter is systematically varying with the polymer. The variation of photovoltage is attributed to the variation of the oxidation potential of the donor conjugated polymers after due consideration of the different injection conditions in the varying polymers.
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| 18. |
- Haglund, Håkan, et al.
(author)
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Snow Accumulation in Real-time
- 2002
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In: Proceedings from SIGRAD 2002. ; , s. 11-15
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Conference paper (peer-reviewed)abstract
- Whenever real-time snowfall is animated in computer games, no snow accumulation is simulated, as far as we know. Instead, so-called zero thickness is used, which means that the blanket of snow does not grow when the snowflakes reach the ground. In this paper we present a method for simulation of snow accumulation, which simulates the different stages, starting with a snow free environment and ending with a totally snow covered scene, all in real-time. The main focus is not on the physical properties of snow but on speed and visual result.
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| 19. |
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| 20. |
- Hedlund, Ann, et al.
(author)
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En studie av ungdomars och anställdas syn på arbete i två kommuner i Dalarna
- 2003
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In: Arbete och hälsa. - 0346-7821. ; 2, s. 52-
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Journal article (peer-reviewed)abstract
- A study of youths and employees opinions on work in two municipalities in Dalarna During the second half of the 1980:s attention was drawn to the difficulties for the industry to recruite youths. The difficulties to recruite had been made worse partly as a result of the decreasing batch of youths, partly of youths negative attitudes towards industrial work. When the state of the market turned to increased prosperity during the second half of the 1990:s, the difficulties in recruiting returned to... mer the agenda. The primary purpose of the study provides a data foundation for discussions in a development project aimed at increasing the attractiveness of manufacturing industry as a workplace. Other purposes concerns youths and employees opinions on ideal work and on industrial work. The study was turned towards youths in the ninth grade and to employees in small engineering workshops and in loghouse firms. The study was delimited to the municipalities Avesta and Rättvik in Dalarna, Sweden. The youths had higher estimates than the employees in both ideal and industrial work. The working environment, including physical, social and working organisational aspects, is the one aspect that the youths has put forward as most important for the firms to improve. Improvement in the working environment may be a suitable strategy to increase the interest for manufacturing and industrial work. A result of the study is that the environment and the treatment that youths experience in the contact with industry firms, e.g. by practical occupational experience, educational visits etc., has great importance for the youths opinion on work within the manufacturing industry.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Lövgren, Mattias, 1974-
(author)
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Accessory factors for ribosomal assembly
- 2004
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Doctoral thesis (other academic/artistic)abstract
- The assembly of ribosomal RNA (rRNA) and ribosomal proteins (r-proteins) into ribosomal subunits (30S and 50S) is a complex process. Transcription of rRNA requires antitermination proteins and the primary transcripts are processed by ribonucleases. R-proteins and rRNAs are chemically modified, the r-proteins bind to the rRNAs and the formed RNA-protein complexes are folded into mature ribosomal subunits. All these processes are well-coordinated and overlapping. Non-ribosomal factors are required for proper assembly and maturation of the ribosomal subunits. Two of these factors are the RimM and RbfA proteins, which bind to 30S subunits and are important for efficient processing of 16S rRNA. Lack of either RimM or RbfA results in a reduced amount of polysomes and a lower growth rate. An increased amount of RbfA can partially compensate for deficiencies shown by a RimM lacking mutant.Here, mutations that alter phylogenetically conserved amino acids in RimM have been constructed. One of these (rimM120), which resulted in the replacement of two adjacent tyrosines by alanines, reduced the growth rate three-fold and also decreased the processing efficiency of 16S rRNA. The RimM120 mutant protein showed a much reduced binding to the 30S subunits. Suppression of the rimM120 mutant was achieved by increased amount of the RimM120 protein, by overexpression of rbfA, or by mutations that changed r-protein S19 or 16S rRNA. A variant of r-protein S13, which was previously isolated as a suppressor to a deletion of rimM (∆rimM), suppressed also the rimM120 mutation. The wild-type RimM protein, but not the RimM120 protein, was shown to bind r-protein S19 in the 30S subunits. The changes in S13, S19 and 16S rRNA that compensated for the deficiencies shown by the rimM mutants are all located within a small region of the head of the 30S subunit, suggesting that this region is the likely target for the RimM action.To isolate RbfA variants that show reduced association with the 30S subunits, phylogenetically conserved, surface exposed amino acid residues of RbfA were changed to alanines or, in some instances, to amino acids of the opposite charge to that in the wild-type protein. Alterations of F5, R31, D46 and D100 had the largest effect on growth.Mutations in the metY-nusA-infB operon, isolated as suppressors to the ∆rimM mutant, were shown to increase the amounts of RbfA. In a ∆rimM mutant, all RbfA protein was found associated with the 30S subunits and no free RbfA was detected.The RlmB protein was shown to be the methyltransferase responsible for the formation of Gm2251 in 23S rRNA in Escherichia coli. Unlike a Saccharomyces cerevisiae mutant that lacks the orthologue to RlmB, Pet56p, which methylates mitochondrial rRNA, a ∆rlmB mutant did not show any defects in ribosomal assembly.
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| 25. |
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| 26. |
- Norberg, Ole, 1970-, et al.
(author)
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Focusing on Paper Properties in Color Characterization of Printing Situations
- 2002
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In: NIP18: International Conference on Digital Printing Technologies. - 0892082402 ; , s. 774-776
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Conference paper (peer-reviewed)abstract
- procedure involving not only the paper itself but also the various printers used. In a situation where the number of printing devices grows rapidly, there is a need for an efficient characterization procedure. The work reported here is an ongoing development of building a library of characterization procedures. These procedures can be applied to printing situations with different combinations of paper grades and printing engines. Special emphasis is put on the influence of the paper properties. Color characterization of printing devices is normally performed using color charts based on different combinations of process colors. These charts are often adapted to certain printing technologies. For an example, the IT8 color chart works well for offset printing but is certainly not optimal in all digital printing situations. The starting point in this development is the selection of a set of equidistant percepts from a homogenous color space. An example of a building block is color separation with respect to halftoning techniques and available inks or toners. Another is the characterization of the physical properties of the paper substrate. The result of the new procedure for color characterization of printing papers correlates with existing methods. It has also contributed to a deeper understanding of the large influence paper has on the final print quality.
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| 27. |
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| 28. |
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| 29. |
- Ruseckas, Arvydas, et al.
(author)
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Luminescence quenching by inter-chain aggregates in substituted polythiophenes
- 2001
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In: Journal of Photochemistry and Photobiology, A: Chemistry. - 1873-2666 .- 1010-6030. ; 144:1, s. 3-12
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Journal article (peer-reviewed)abstract
- Time-resolved photo luminescence spectra measured in solid films of two polythiophene derivatives with different chain packing allow to distinguish emission of intra-chain excitations from the luminescence of inter-chain aggregates. Aggregate luminescence is red shifted by about 0.1 eV relative to intra-chain emission and shows vibronic coupling to the C=C bond stretch with the Huang-Phys factor of S approximate to 1.5, which is twice bigger than that of the intra-chain emission. Combining time resolved luminescence data with femtosecond transient absorption, we show that the dynamic quenching of the luminescence in films with dense chain packing is mainly due to excitation energy transfer to aggregates. The radiative lifetime of the lowest excited state of the aggregate with the optical gap of 1.84-1.9 eV is estimated to be about 20 ns. The aggregate contribution to the total luminescence in the polythiophene films with dense chain packing is about 50% and does not change significantly with temperature. (C) 2001 Elsevier Science B.V. All rights reserved.
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| 30. |
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| 31. |
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| 32. |
- Wiberg, Kent, et al.
(author)
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Peak purity determination with principal component analysis of high-performance liquid chromatography-diode array detection data
- 2004
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In: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1029:1-2, s. 13-20
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Journal article (peer-reviewed)abstract
- A method is proposed for the determination of chromatographic peak purity by means of principal component analysis (PCA) of high-performance liquid chromatography with diode array detection (HPLC–DAD) data. The method is exemplified with analysis of binary mixtures of lidocaine and prilocaine with different levels of separation. Lidocaine and prilocaine have very similar spectra and the chromatograms used had substantial peak overlap. The samples analysed contained a constant amount of lidocaine and a minor amount of prilocaine (0.02–2 conc.%) and hence the focus was on determining the purity of the lidocaine peak in the presence of much smaller levels of prilocaine. The peak purity determination was made by examination of relative observation residuals, scores and loadings from the PCA decomposition of DAD data over a chromatographic peak. As a reference method, the functions for peak purity analysis in the chromatographic data system used (Chromeleon) were applied. The PCA method showed good results at the same level as the detection limit of baseline-separated prilocaine, outperforming the methods in Chromeleon by a factor of ten. There is a discussion of the interpretation of the result, with some comparisons with evolving factor analysis (EFA). The main advantage of the PCA method for determination of peak purity over methods like EFA lies in its simplicity, short time of calculation and ease of use.
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| 33. |
- Wiberg, Kent, et al.
(author)
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Use of control sample for estimation of prediction error in multivariate determination of lidocaine solutions with non-column chromatographic diode array UV spectroscopy
- 2003
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In: Journal of Pharmaceutical and Biomedical Analysis. - 0731-7085 .- 1873-264X. ; 33:5, s. 859-869
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate the ability of a control sample, of known content and identity, to diagnose and correct errors in the predictions when the same multivariate calibration model was used for analysis of new samples over time. A calibration set consisting of 16 samples with a known content of lidocaine was analysed and two external test sets, A and B, were used for the validation. Test set A contained 15 samples with different concentrations of lidocaine and test set B contained three samples with different lidocaine content, which were analysed six times in order to obtain a measure of repeatability. The multivariate calibration was done with PLS regression on UV spectra collected between 245 and 290 nm. A representative UV spectrum was exported from the collected DAD files by two methods, average spectrum over the whole file and average spectrum over the sample plug. Test set A was analysed further on another three occasions together with a control sample. The results showed that the control sample could be used to give a diagnosis and estimate of the prediction error. Moreover, the measured prediction error of the control sample could also be used to correct the predictions, thereby reducing the prediction error. Finally, some practical considerations regarding use of the proposed DAD method with a control sample are presented. The procedure suggested could lead to an efficient analytical approach where the same calibration model could be used over time without recalibration, which may be attractive in industrial quality control or screening analysis in pharmaceutical research.
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| 34. |
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