Hannu Heusala

Cosimulation of real-time control systems

The behaviour of a real-time system can be validated at the system level by means of a real-time operating system model in a VHDL simulation environment. The model consists of the real-time operating system, hardware described in behavioural VHDL and task descriptions written in C. The real-time operating system behaviour, HW/SW partitioning and HW/SW interfacing can be analysed by studying the simulation results.

Microprocessor-Based Flow Measurement Using a Positron Active Tracer

Methods for liquid-flow measurement based on the transit time of a positron active source are described, and the accuracy of each method is estimated. A microprocessor-based system and a TTL integrator for studying a positron active flow is constructed. The theoretical and experimental studies show that the velocity of a point source, 111 kBq (3¿Ci) Na22-isotope (¿ 1 mm) inside a metal pipe (¿ 42 mm) can be measured using annihilation coincidence detection (detector pairs 1 m apart) and microprocessor electronics with inaccuracies of 0.2, 0.5, 0.7 percent for velocities 0.1, 0.5, and 1.0 m/s, respectively, at the 95 percent level of significance. Greater accuracy can be achieved by increasing the activity of the source.

Gamma Ray Absorption Measurement Using Positron Annihilation Coincidence Detection

A new principle of density and thickness measurement by gamma ray absorption is developed. The standard deviation of the density and thickness readings caused by the natural randomness of a gamma emitter can be effectively reduced by applying detection of two identical photons produced by positron annihilation. It can be shown that the relation of the original annihilation rate to that absorbed in the material is a function of thickness and density, and the deviation of the readings depends on the efficiency of the detectors. Twice the accuracy of the conventional single gamma counting method can be achieved with a detector efficiency of 62%. A better efficiency gives higher accuracy.

Management of innovation and new product development-theory and a case study

Theory and a case study of innovation management in technology start-up company, which is organized like a virtual enterprise, is described. The theory is based on the understanding of electronics industry as a composition of specific information and material flows. The product analysis based on the model leads to the business plan of a virtual enterprise. IPR management and valuation is the key issue in this approach. A short theoretical background for the issue is given. The theory description consists of a list of definitions and a diagram showing the relations between them.

Design Considerations for Positron Transmission Tomograph Used for Non-Medical Applications

Design considerations for a positron transmission tomograph to be used for the crosssectional density distribution and dimensions measurements of metal or plastic sheets is described. A low cost piece of equipment constructed for performance studies of the transmission tomography is also described. The camera design consists of a small detector ring with a fixed positron active source in the middle of it. This transmission camera is independent of short half-life isotopes and a nearby cyclotron. It is possible to determine the type of an interaction between a photon and the object material and also the geometric line where the first interaction has taken place using positron annihilation coincidence detection. One of the photons in every annihilation pair escapes from the source into a known direction. A photon will scatter once or more in the object, penetrate it or become totally absorbed by it. The density distribution or the dimensions of the object material can be reconstructed from the count rates of interactions correponding to different projection angles. The detector array with a 10 cm (inner) and 40 cm (outer) diameter consisting of 34 crystals is capable of detecting an annihilation count rate of 1500 events/s¿Ci. Thie calculated maximum cross-sectional area of the photon beam is from 3×3 mm2 to 8.4×9.2 mm2 in the middle and 16×18 mm2 at each end of the view.

Application of Positron Annihilation Coincidence Detection (ACD) and Digital Data Analysis to Water Flow Velocity Measurements in a Pipe

Measurements of water flow at different velocities in two kinds of pipe are made using a sealed positron tracer and annihilation coincidence detection. The main aim is to find the most suitable hardware and software construction for analyzing the liquid flow and velocity profile in a pipe using the ACD method. The present measurements with previous calculations show that the mass flow of water can be measured with an accuracy greater than 1 %.

Gamma Ray Pattern Analysis by Fast Scintillation Timing

A position sensitive detector is needed for gamma ray pattern analysis and in this study the usual pulse height method has been replaced by the transit time method using the time of flight principle. Two photomultipliers were attached to the ends of a plastic scintillator rod and the time delay between the observed signals was recorded and converted into a position reading. The position resolution was measured by using a narrow collimated gamma ray beam penetrating the rod transversally at a certain position. The transit time difference from the scintillation position to each photomultiplier was measured with a positron lifetime spectrometer giving a position resolution of between 11 mm and 23 mm. The results of the measurements and relevant applications have been discussed including the positron camera and angular correlation apparatus.

Modeling of a Reconfigurable OFDM IP Block Family For an RF System Simulator

The idea of designing a domain specific mother model of an IP block family as a basis for modeling of system integration is presented here. A common reconfigurable mother model for ten different standardized digital OFDM transmitters has been developed. By means of a set of parameters, the mother model can be reconfigured to any of the ten selected standards. So far the applicability of the proposed reconfiguration and analog-digital co-modeling methods have been proved by modeling the function of the digital parts of three, IEEE 802.11a, ADSL and DRM, transmitters in an RF system simulator. The model is intended to be used as signal source template in RF system simulations. The concept is not restricted to signal sources, it can be applied to any IP block development. The idea of the mother model is applied in other design domains to prove that in certain application areas, OFDM transceivers in this case, the design process can progress simultaneously in different design domains - mixed signal, system and RTL-architectural - without the need for high-level synthesis. Only the mother models of three design domains are needed to be formally proved to function as specified.

Application of decision-making method for architecture selection of ADSL modem

This paper presents a method for assisting the decision-making of the technologies and architectures of system chips. The method combines functional complexity analyses, reuse of intellectunl property blocks, technology forecasts and functionality-architecture mappings into unifom measure of architecture quality. This figure of quality can be used in rapid comparison of architecture alternatives, without the need of detailed design or specification. The method has been applied to ADSL modem architectures for the comparison of feasibilities. The best architectures found were similar to commercially available ADSL chip sets. The method extends traditional complexity analyses by taking into account improvements in technologies and tools. It reduces the risks involved in strategic decisions at early stages of design, when the essential product characteristics are determined.

Performance Analysis of an Industrial Positron Transmission Tomograph

The concept of positron transmission tomography is described. The signal-to-noise ratio of measured positron transmission raysums is two times better than that of conventional single gamma transmission. Ageing of the source does not change calibration of measurement because the intensity of the source is determined during every sampling period. Focusing of the transmission beam can be made electronically. Information containing in scattered events can be processed.