[diss] Perustieteiden korkeakoulu / SCI

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Calorimetric measurements of hyperfine interactions in some metals
(Helsinki University of Technology, 1971) Krusius, Matti; Collan, H. K.; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Picket, G. R.
Some heat capacity and thermometric investigations at ultralow temperatures
(Helsinki University of Technology, 1971-10-01) Collan, Heikki K.; Department of Technical Physics; Teknillisen fysiikan osasto; Low Temperature Laboratory; Kylmälaboratorio; Lounasmaa, Olli V.; Prof.
An experimental investigation on the superfluidity of [sup 3]He
(Helsinki University of Technology, 1974) Alvesalo, Tapio; Collan, H. K.; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
Critical flow and persistent current experiments in superfluid [sup 3]He
(Helsinki University of Technology, 1984) Pekola, Jukka P.; Packard, Richard; Manninen, Mikko; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
Neuromagnetism: Theory, techniques, and measurements
(Helsinki University of Technology, 1985) Ilmoniemi, Risto; Lounasmaa, Olli; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
Development of multichannel SQUID magnetometers for neuromagnetic measurements
(Helsinki University of Technology, 1987) Knuutila, Jukka; Ahonen, Antti; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
Interpretation of neuromagnetic measurements : modeling and statistical considerations
(Helsinki University of Technology, 1987) Hämäläinen, Matti; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
Magnetic resonance imaging at 0.02 T : design and evaluation of radio frequency coils with wave winding
(Helsinki University of Technology, 1988) Savelainen, Matti; Sepponen, Raimo; Collan, Heikki; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science
The thesis deals with the theoretical principles, design and construction of wave-wound radio frequency coils for low field magnetic resonance imaging. The coils can be tuned to emit and detect circularly polarized radio frequency field. The principles and design of the tuning circuit are described. The performance of the wave-wound coils and tuning circuits is analyzed on the basis of numerical simulations and experimental studies. Guidelines for the design of high performance coils are given. Four wave-wound coils have been designed and constructed for clinical magnetic resonance imaging. Properties and examples of the imaging results of these coils are presented.
Analysis of left ventricular function by optimization models
(1988) Hämäläinen, Jari J.; Perustieteiden korkeakoulu; School of Science
The development of a new hierarchical optimization model for explaining left ventricular function is summarized. In the model, arterial load is described by three linear time-invariant differential equations. End-diastolic volume, linear end-systolic pressure-volume relation, heart rate, and nominal ejection time are given. Under these constraints, ventricular function is described by optimality criteria that are based on minimizing an index of myocardial oxygen consumption per beat. Also forces developed during ejection and ventricular efficiency are taken into account in the cost functions of the model. The model predicts ventricular stroke volume, time courses of root aortic flow and pressure, and ejection time. These predictions are in accordance with experimental data from an isolated canine heart preparation. In the measurements analyzed, arterial load has been changed while end-diastolic volume, contractility, and heart rate have been kept constant. Thus the analysis shows that the left ventricular response to a change in arterial load can be predicted by an optimization model. The results also suggest that energy economy and efficiency are essential features of left ventricular function.
Construction of the rotating cryostat ROTA2, its use for zero sound experiments in 3He-B, and calculations of ion mobility in 3He-A and 3He-P
(Helsinki University of Technology, 1989) Salmelin, Riitta; Pekola, Jukka; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Berglund, Peter
Ion transmission and NMR in rotating superfluid 3He
(Helsinki University of Technology, 1992) Korhonen, Juha; Hakonen, Pertti; Nummila, Kaj; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Krusius, Matti
Theoretical studies on nuclear magnetic ordering in copper and silver
(Helsinki University of Technology, 1992) Viertiö, Hanna; Oja, Aarne; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Nieminen, Risto
Acoustic and optical investigations of superfluid 3He
(Helsinki University of Technology, 1993) Manninen, Antti; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Pekola, Jukka
Magnetic source imaging of visually evoked and oscillatory electrical activity of the human brain
(Helsinki University of Technology, 1994) Ahlfors, Seppo; Kylmälaboratorio; Low Temperature Laboratory; Perustieteiden korkeakoulu; School of Science
Neutron Experiments on Nuclear Magnetism in Copper and Silver
(Helsinki University of Technology, 1995) Tuoriniemi, Juha; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Nummila, Kaj; Oja, Aarne
Interferometric and Acoustic Measurements in Superfluid 3He-B and Wetting Studies in 3He/4He Mixtures
(Helsinki University of Technology, 1995) Alles, Harry; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Pekola, Jukka; Hakonen, Pertti
A Versatile Nuclear Demagnetization Cryostat for Ultralow Temperature Research
(Helsinki University of Technology, 1997) Yao, Weijun; Nummila, Kaj; Oja, Aarne; O.V. Lounasmaa -laboratorio; O.V. Lounasmaa Laboratory; Perustieteiden korkeakoulu; School of Science; Hautojärvi, Pekka
A new cascade nuclear demagnetization cryostat has been designed and constructed. Our aim was to build a versatile, modular cryostat, with a large experimental space providing an excellent platform for various types of ultra-low temperature measurements. A powerful dilution refrigerator, combined with a massive copper nuclear cooling stage, will enable us to reach the low temperatures necessary in studies of nuclear magnetic ordering. First experiments will include nuclear magnetism in Rh and search for superfluidity of 3He in the dilute 3He/4He mixture. Details of the design and results of the performance tests will be presented. The suitability of normal metal tunnel junction chains for primary thermometry at mK temperatures has been studied. Preparations of experiments for studies of nuclear magnetic ordering in rhodium will be described as well.
Subspace classifiers in recognition of handwritten digits
(Helsinki University of Technology, 1997-05-07) Laaksonen, Jorma; Department of Computer Science and Engineering; Tietotekniikan osasto; Laboratory of Computer and Information Science; Informaatiotekniikan laboratorio
This thesis consists of two parts. The first part reviews the general structure of a pattern recognition system and, in particular, various statistical and neural classification algorithms. The presentation then focuses on subspace classification methods that form a family of semiparametric methods. Several improvements on the traditional subspace classification rule are presented. Most importantly, two new classification techniques, here named the Local Subspace Classifier (LSC) and the Convex Local Subspace Classifier (LSC+), are introduced. These new methods connect the subspace principle to the family of nonparametric prototype-based classifiers and, thus, seek to combine the benefits of both approaches. The second part addresses the recognition of handwritten digits, which is the case study of this thesis. Special attention is given to feature extraction methods in optical character recognition systems. As a novel contribution, a new method, here named the error-corrective feature extraction, is presented. The prototype recognition system developed for the experiments is described and various options in the implementation are discussed. For the background of the experiments, thirteen well-known statistical and neural classification algorithms were tested. The results obtained with two traditional subspace methods and ten novel techniques presented in this thesis are compared with them. The results show that the Convex Local Subspace Classifier performs better than any other classification algorithm in the comparison. The conclusions of this thesis state that the suggested enhancements make the subspace methods very useful for tasks like the recognition of handwritten digits. This result is expected to be applicable in other similar cases of recognizing two-dimensional isolated visual objects.
Realising the potential of traceability : a case study research on usage and impacts of product traceability
(Helsinki University of Technology, 1999-03-26) Töyrylä, Ilkka; Department of Industrial Engineering and Management; Tuotantotalouden osasto
This thesis studies the use and impacts of product traceability in business enterprises. Prior research in the field of traceability is scarce and fragmented. This study first draws together and explores the existing body of knowledge to identify the state of current understanding and the gaps that remain in it. Moreover, this study identifies the position of traceability as a discipline with respect to related subjects including product data management. Furthermore, it analyses the ability of these subjects to help to understand the problems in the field of traceability. Based on the gaps identified in the existing body of knowledge, the following research questions are raised: How is traceability data used in business enterprises? What are the impacts and benefits of using traceability data? What factors enable a business enterprise to fully realise the positive impacts of traceability data? The research questions are answered using the case-study methodology. The use of traceability is studied in nine different companies from automobile, food, electronics, pharmaceuticals and transportation industries. The case-study research begins with a description of the case-study companies as stand-alone entities, after which the cross-case analysis is conducted. The empirical study establishes a theoretical and a pragmatic framework for categorising the applications of traceability. Moreover, it identifies a multitude of ways of using traceability data in business enterprises. The results of analysing the impacts and benefits of traceability data point out the importance of traceability for business enterprises. A framework for categorising the impacts of using traceability data as well as a number of practical benefits resulting from the use of this data emerge. Finally, several factors in the organisational and technical setting contributing to the realisation of these benefits are identified. Altogether, this study establishes the foundations of comprehensively understanding the phenomenon of traceability.
Promotion of values in a multinational enterprise
(Helsinki University of Technology, 1999-09-18) Martinsuo, Miia; Vartiainen, Matti; Department of Industrial Engineering and Management; Tuotantotalouden osasto; Laboratory of Work Psychology and Leadership; Teollisuustalouden ja työpsykologian laboratorio
This study focuses on the promotion of values as a way for organizational managers to influence operations in a multinational enterprise (MNE). Despite the continued centrality of the organizational culture concept in management literature, and the need for dynamics in a turbulent business environment, managing culture has been considered difficult or even impossible. This study concentrates on one part of organizational culture, namely organizational members' beliefs as a potentially malleable target of managerial intervention. Values are introduced as a sufficiently abstract and general vehicle for influencing organizational beliefs, while the promotion of values means the practices and procedures used to increase value-related awareness and action. In a multinational enterprise, influencing beliefs and promoting values may be especially challenged due to the diverse beliefs of employees. Extant literature has not covered this area sufficiently. The objectives of the study are to increase understanding of the context and target, content and means, and the process and practices for promoting values in a multinational enterprise, and to discover factors relevant to promoting values successfully. In a qualitative, holistic single-case study setting, the research examines a successful multinational enterprise, Nokia, and its approach to promoting values. Semi-structured interviews with employees, middle managers and top managers are used as a primary source of data. Additionally, various internal and public documents, value-related materials, and observations are used as support for the interviews. The results confirm organizational beliefs as the malleable target of managerial intervention particularly when the firm maintains a proactive stance towards its environment. The business unit position in relation to an organizational core, and external, global and local orientation are suggested as dimensions to be identified when managing beliefs in an MNE. Values are characterized as a moving target in the field of organizational identity and culture beliefs of organizational members. The significance of constant reinterpretation of values is emphasized, if management wishes to use values as a vehicle for managerial intervention. Acknowledgement of ambiguity is raised as central to making the promotion of values successful. In addition to localizing the promotion of values, firms should develop practices that are particularly focused on managing the ambiguities rather than striving for operational consistency across the range of different subcultures. Practical ideas are presented on how the promotion of values could take place in a global firm. The qualitative case study in a successful multinational firm provides important input on how the promotion of values takes place at its best. Many questions still remain unanswered, among them the actual impact of promoting values, the process of adopting values and other types and stages of managerial intervention than the promotion of values.

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