Nonlinear dynamics and control of multibody systems

The dynamics of flexible systems, such as robot manipulators , mechanical chains or multibody systems in general, is becoming increasingly important in engineering. This article deals with some nonlinearities that arise in the study of dynamics and control of multibody systems in connection to large rotations. Specifically, a numerical scheme that adresses the conservation of fundamental constants is presented in order to analyse the control-structure interaction problems.

Identification of flexural stiffness parameters of beams

A three degree of freedom model of the dynamic mass at the middle of a test sample, resembling a Stockbridge neutraliser, is introduced. This model is used to identify the hereby called equivalent complex cross section flexural stiffness (ECFS) of the beam element which is part of the whole test sample. This ECFS, once identified, gives the effective cross section flexural stiffness of the beam as well as its effective damping, measured as the loss factor of an equivalent viscoelastic beam. The beam element of the test sample may be of any complexity, such as a segment of stranded cable of the ACSR type. These data are important parameters for the design of overhead power transmission lines and other cable structures. A cost function is defined and used in the identification of the ECFS. An experiment, designed to measure the dynamic masses of two test samples, is described. Experimental and identified results are presented and discussed.

Identification of Flexural Stiffness Parameters of Beams

A three degree of freedom model of the dynamic mass at the middle of a test sample, resembling a Stockbridge neutraliser, is introduced. This model is used to identify the hereby called equivalent complex cross section flexural stiffness (ECFS) of the beam element which is part of the whole test sample. This ECFS, once identified, gives the effective cross section flexural stiffness of the beam as well as its effective damping, measured as the loss factor of an equivalent viscoelastic beam. The beam element of the test sample may be of any complexity, such as a segment of stranded cable of the ACSR type. These data are important parameters for the design of overhead power transmission lines and other cable structures. A cost function is defined and used in the identification of the ECFS. An experiment, designed to measure the dynamic masses of two test samples, is described. Experimental and identified results are presented and discussed.

Variable structure position control of an industrial robotic manipulator

The use of a robust position controller for a robotic manipulator moving in free space is presented. The aim is to implement in practice a controller that is robust to uncertainties in the model of the system, as well as being inexpensive from a computational point of view. Variable structure theory provides the technique for the design of such controller. The design steps are presented, first from a theoretical perspective and then applied to the control of a two degree-of-freedom manipulator. Simulation results that backed the implementation are presented, followed by the experiments conducted and the results that were obtained. The conclusion is that variable structure control is readily applicable to industrial robots for the robust control of positions.

In search of information systems value : a case study of the EHR benefits realisation efforts of three Swedish hospitals.

The Swedish public health care organisation could very well be undergoing its most significant change since its specialisation during the late 19th and early 20th century. At the heart of this change is a move from using manual patient journals to electronic health records (EHR). EHR are complex integrated organisational wide information systems (IS) that promise great benefits and value as well as presenting great challenges to the organisation. The Swedish public health care is not the first organisation to implement integrated IS, and by no means alone in their quest for realising the potential benefits and value that it has to offer. As organisations invest in IS they embark on a journey of value-creation and capture. A journey where a costbased approach towards their IS-investments is replaced with a value-centric focus, and where the main challenges lie in the practical day-to-day task of finding ways to intertwine technology, people and business processes. This has however proven to be a problematic task. The problematic situation arises from a shift of perspective regarding how to manage IS in order to gain value. This is a shift from technology delivery to benefits delivery; from an ISimplementation plan to a change management plan. The shift gives rise to challenges related to the inability of IS and the elusiveness of value. As a response to these challenges the field of IS-benefits management has emerged offering a framework and a process in order to better understand and formalise benefits realisation activities. In this thesis the benefits realisation efforts of three Swedish hospitals within the same county council are studied. The thesis focuses on the participants of benefits analysis projects; their perceptions, judgments, negotiations and descriptions of potential benefits. The purpose is to address the process where organisations seek to identify which potential IS-benefits to pursue and realise, this in order to better understand what affects the process, so that realisation actions of potential IS-benefits could be supported. A qualitative case study research design is adopted and provides a framework for sample selection, data collection, and data analysis. It also provides a framework for discussions of validity, reliability and generalizability. Findings displayed a benefits fluctuation, which showed that participants’ perception of what constituted potential benefits and value changed throughout the formal benefits management process. Issues like structure, knowledge, expectation and experience affected perception differently, and this in the end changed the amount and composition of potential benefits and value. Five dimensions of benefits judgment were identified and used by participants when finding accommodations of potential benefits and value to pursue. Identified dimensions affected participants’ perceptions, which in turn affected the amount and composition of potential benefits. During the formal benefits management process participants shifted between judgment dimensions. These movements emerged through debates and interactions between participants. Judgments based on what was perceived as expected due to one’s role and perceived best for the organisation as a whole were the two dominant benefits judgment dimensions. A benefits negotiation was identified. Negotiations were divided into two main categories, rational and irrational, depending on participants’ drive when initiating and participating in negotiations. In each category three different types of negotiations were identified having different characteristics and generating different outcomes. There was also a benefits negotiation process identified that displayed management challenges corresponding to its five phases. A discrepancy was also found between how IS-benefits are spoken of and how actions of IS benefits realisation are understood. This was a discrepancy between an evaluation and a realisation focus towards IS value creation. An evaluation focus described IS-benefits as well-defined and measurable effects and a realisation focus spoke of establishing and managing an on-going place of value creation. The notion of valuescape was introduced in order to describe and support the understanding of IS value creation. Valuescape corresponded to a realisation focus and outlined a value configuration consisting of activities, logic, structure, drivers and role of IS.

A Survey about Integration of Journal Systems with Repositories in Brazil

Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Dual light barrier method for six degrees of freedom tool center point calibration of an industrial robot

Tool center point calibration is a known problem in industrial robotics. The major focus of academic research is to enhance the accuracy and repeatability of next generation robots. However, operators of currently available robots are working within the limits of the robot´s repeatability and require calibration methods suitable for these basic applications. This study was conducted in association with Stresstech Oy, which provides solutions for manufacturing quality control. Their sensor, based on the Barkhausen noise effect, requires accurate positioning. The accuracy requirement admits a tool center point calibration problem if measurements are executed with an industrial robot. Multiple possibilities are available in the market for automatic tool center point calibration. Manufacturers provide customized calibrators to most robot types and tools. With the handmade sensors and multiple robot types that Stresstech uses, this would require great deal of labor. This thesis introduces a calibration method that is suitable for all robots which have two digital input ports free. It functions with the traditional method of using a light barrier to detect the tool in the robot coordinate system. However, this method utilizes two parallel light barriers to simultaneously measure and detect the center axis of the tool. Rotations about two axes are defined with the center axis. The last rotation about the Z-axis is calculated for tools that have different width of X- and Y-axes. The results indicate that this method is suitable for calibrating the geometric tool center point of a Barkhausen noise sensor. In the repeatability tests, a standard deviation inside robot repeatability was acquired. The Barkhausen noise signal was also evaluated after recalibration and the results indicate correct calibration. However, future studies should be conducted using a more accurate manipulator, since the method employs the robot itself as a measuring device.

Assessment of the degree of contamination of rat germ cell preparations using specific cDNA probes

Recent reports showing a decrease in sperm count in men have brought new concerns about male infertility. Animal models have been widely used to provide some relevant information about the human male gamete, and extrapolations are made to men and to the clinical context. The present study assesses one of the methods used for separation of germ cells of the adult rat testis, namely centrifugal elutriation followed by density gradients (Percoll®). This method was chosen since it presents the best results for cell purity in separating germ cells from the rat testis. A comparison between continuous and discontinuous Percoll® gradients was performed in order to identify the best type of gradient to separate the cells. Maximal cell purity was obtained for spermatocytes (81 ± 8.2%, mean ± SEM) and spermatids (84 ± 2.6%) using centrifugal elutriation followed by continuous Percoll® gradients. A significant difference in purity was observed between elongating spermatids harvested from continuous Percoll® gradients and from discontinuous gradients. Molecular analysis was used to assess cell contamination by employing specific probes, namely transition protein 2 (TP2), mitochondrial cytochrome C oxidase II (COX II), and sulfated glycoprotein 1 (SGP1). Molecular analysis of the samples demonstrated that morphological criteria are efficient in characterizing the main composition of the cell suspension, but are not reliable for identifying minimal contamination from other cells. Reliable cell purity data should be established using molecular analysis

Relation of the disaccharidases in the small intestine of the rat to the degree of experimentally induced iron-deficiency anemia

Hypolactasia associated with severe iron-deficiency anemia has been reported in several studies. The objective of the present study was to determine whether hypolactasia is associated with the degree and duration of iron-deficiency anemia. Newly weaned male Wistar rats were divided into a control group receiving a diet supplemented with iron (C) and an experimental group (E) receiving a diet not supplemented with iron (iron-deficiency diet). The animals were studied on the 3rd, 5th, 7th, 14th, 21st, 28th and 35th days of the experiment, when overall and iron nutritional status and disaccharidase activity in the small intestine were determined by the Dahlqvist method. A reduction in weight occurred in the anemic animals starting on the 5th day of the study. Anemia was present in the experimental animals, with a progressive worsening up to the 14th day (hemoglobin: C = 13.27 and E = 5.37) and stabilizing thereafter. Saccharase and maltase activities did not differ significantly between groups, whereas lactase showed a significant reduction in total (TA) and specific activity (SA) in the anemic animals starting on the 21st day of the study. Median lactase TA for the C and E groups was 2.27 and 1.25 U on the 21st day, 2.87 and 1.88 U on the 28th day, and 4.20 and 1.59 U on the 35th day, respectively. Median lactase SA was 0.31 and 0.20 U/g wet weight on the 21st day, 0.39 and 0.24 U/g wet weight on the 28th day, and 0.42 and 0.23 U/g wet weight on the 35th day, respectively. These findings suggest a relationship between the enzymatic alterations observed and both the degree and duration of the anemic process. Analysis of other studies on intestinal disaccharidases in anemia suggests that the mechanism of these changes may be functional, i.e., that the enterocytes may suffer a reduction in their ability to synthesize these enzymes.

A single strain of Mycobacterium bovis bacillus Calmette-Guérin (BCG) grown in two different media evokes distinct humoral immune responses in mice

Two attenuated bacillus Calmette-Guérin (BCG) preparations derived from the same Moreau strain, Copenhagen but grown in Sauton medium containing starch and bacto-peptone (onco BCG, O-BCG), or asparagine (intradermal BCG, ID-BCG), exhibited indistinguishable DNA sequences and bacterial morphology. The number of viable bacilli recovered from spleen, liver and lungs was approximately the same in mice inoculated with the vaccines and was similarly reduced (over 90%) in mice previously immunized with either BCG vaccine. The humoral immune response evoked by the vaccines was, however, distinct. Spleen cell proliferation accompanying the growth of bacilli in tissue was significantly higher in mice inoculated with O-BCG. These cells proliferated in vitro upon challenge with the corresponding BCG extract. Previous cell treatment with mAb anti-CD4 T cells abolished this effect. Anti-BCG antibodies, as assayed either in serum by ELISA or by determining the number of antibody-producing spleen cells by the spot-ELISA method, were significantly higher in mice inoculated with ID-BCG. Anti-BCG antibodies were detected in all immunoglobulin classes, but they were more prevalent in IgG with the following distribution among its isotypes: IgG1>(IgG2a = IgG2b)>IgG3. When some well-characterized Mycobacterium tuberculosis antigens were used as substitutes for BCG extracts in ELISA, although antibodies against the 65-kDa and 96-kDa proteins were detected significantly, antibodies against the 71-kDa, 38-kDa proteins and lipoarabinomannan were only barely detected or even absent. These results indicate that BCG bacilli cultured in Sauton-asparagine medium permitted the multiplication of bacilli, tending to induce a stronger humoral immune response as compared with bacilli grown in Sauton-starch/bacto-peptone-enriched medium.

The collective dimension of freedom of religion or belief in international law : the application of findings to the case of Turkey

Pertinent domestic and international developments involving issues related to tensions affecting religious or belief communities have been increasingly occupying the international law agenda. Those who generate and, thus, shape international law jurisprudence are in the process of seeking some of the answers to these questions. Thus the need for reconceptualization of the right to freedom of religion or belief continues as demands to the right to freedom of religion or belief challenge the boundaries of religious freedom in national and international law. This thesis aims to contribute to the process of “re-conceptualization” by exploring the notion of the collective dimension of freedom of religion or belief with a view to advance the protection of the right to freedom of religion or belief. The case of Turkey provides a useful test case where both the domestic legislation can be assessed against international standards, while at the same time lessons can be drawn for the improvement of the standard of international review of the protection of the collective dimension of freedom of religion or belief. The right to freedom of religion or belief, as enshrined in international human rights documents, is unique in its formulation in that it provides protection for the enjoyment of the rights “in community with others”.1 It cannot be realized in isolation; it crosses categories of human rights with aspects that are individual, aspects that can be effectively realized only in an organized community of individuals and aspects that belong to the field of economic, social and cultural rights such as those related to religious or moral education. This study centers on two primary questions; first, what is the scope and nature of protection afforded to the collective dimension of freedom of religion or belief in international law, and, secondly, how does the protection of the collective dimension of freedom of religion or belief in Turkey compare and contrast to international standards? Section I explores and examines the notion of the collective dimension of freedom of religion or belief, and the scope of its protection in international law with particular reference to the right to acquire legal personality and autonomy religious/belief communities. In Section II, the case study on Turkey constitutes the applied part of the thesis; here, the protection of the collective dimension is assessed with a view to evaluate the compliance of Turkish legislation and practice with international norms as well as seeking to identify how the standard of international review of the collective dimension of freedom of religion or belief can be improved.

Hemodynamic mechanisms of the attenuated blood pressure response to mental stress after a single bout of maximal dynamic exercise in healthy subjects

To determine the hemodynamic mechanisms responsible for the attenuated blood pressure response to mental stress after exercise, 26 healthy sedentary individuals (age 29 ± 8 years) underwent the Stroop color-word test before and 60 min after a bout of maximal dynamic exercise on a treadmill. A subgroup (N = 11) underwent a time-control experiment without exercise. Blood pressure was continuously and noninvasively recorded by infrared finger photoplethysmography. Stroke volume was derived from pressure signals, and cardiac output and peripheral vascular resistance were calculated. Perceived mental stress scores were comparable between mental stress tests both in the exercise (P = 0.96) and control (P = 0.24) experiments. After exercise, the blood pressure response to mental stress was attenuated (pre: 10 ± 13 vs post: 6 ± 7 mmHg; P < 0.01) along with lower values of systolic blood pressure (pre: 129 ± 3 vs post: 125 ± 3 mmHg; P < 0.05), stroke volume (pre: 89.4 ± 3.5 vs post: 76.8 ± 3.8 mL; P < 0.05), and cardiac output (pre: 7.00 ± 0.30 vs post: 6.51 ± 0.36 L/min; P < 0.05). Except for heart rate, the hemodynamic responses and the mean values during the two mental stress tests in the control experiment were similar (P > 0.05). In conclusion, a single bout of maximal dynamic exercise attenuates the blood pressure response to mental stress in healthy subjects, along with lower stroke volume and cardiac output, denoting an acute modulatory action of exercise on the central hemodynamic response to mental stress.

Model-based testing of software systems : functionality and performance

Software is a key component in many of our devices and products that we use every day. Most customers demand not only that their devices should function as expected but also that the software should be of high quality, reliable, fault tolerant, efficient, etc. In short, it is not enough that a calculator gives the correct result of a calculation, we want the result instantly, in the right form, with minimal use of battery, etc. One of the key aspects for succeeding in today's industry is delivering high quality. In most software development projects, high-quality software is achieved by rigorous testing and good quality assurance practices. However, today, customers are asking for these high quality software products at an ever-increasing pace. This leaves the companies with less time for development. Software testing is an expensive activity, because it requires much manual work. Testing, debugging, and verification are estimated to consume 50 to 75 per cent of the total development cost of complex software projects. Further, the most expensive software defects are those which have to be fixed after the product is released. One of the main challenges in software development is reducing the associated cost and time of software testing without sacrificing the quality of the developed software. It is often not enough to only demonstrate that a piece of software is functioning correctly. Usually, many other aspects of the software, such as performance, security, scalability, usability, etc., need also to be verified. Testing these aspects of the software is traditionally referred to as nonfunctional testing. One of the major challenges with non-functional testing is that it is usually carried out at the end of the software development process when most of the functionality is implemented. This is due to the fact that non-functional aspects, such as performance or security, apply to the software as a whole. In this thesis, we study the use of model-based testing. We present approaches to automatically generate tests from behavioral models for solving some of these challenges. We show that model-based testing is not only applicable to functional testing but also to non-functional testing. In its simplest form, performance testing is performed by executing multiple test sequences at once while observing the software in terms of responsiveness and stability, rather than the output. The main contribution of the thesis is a coherent model-based testing approach for testing functional and performance related issues in software systems. We show how we go from system models, expressed in the Unified Modeling Language, to test cases and back to models again. The system requirements are traced throughout the entire testing process. Requirements traceability facilitates finding faults in the design and implementation of the software. In the research field of model-based testing, many new proposed approaches suffer from poor or the lack of tool support. Therefore, the second contribution of this thesis is proper tool support for the proposed approach that is integrated with leading industry tools. We o er independent tools, tools that are integrated with other industry leading tools, and complete tool-chains when necessary. Many model-based testing approaches proposed by the research community suffer from poor empirical validation in an industrial context. In order to demonstrate the applicability of our proposed approach, we apply our research to several systems, including industrial ones.

Development of Measurement Systems in Scientific Research: Case Study

In recent years, technological advancements in microelectronics and sensor technologies have revolutionized the field of electrical engineering. New manufacturing techniques have enabled a higher level of integration that has combined sensors and electronics into compact and inexpensive systems. Previously, the challenge in measurements was to understand the operation of the electronics and sensors, but this has now changed. Nowadays, the challenge in measurement instrumentation lies in mastering the whole system, not just the electronics. To address this issue, this doctoral dissertation studies whether it would be beneficial to consider a measurement system as a whole from the physical phenomena to the digital recording device, where each piece of the measurement system affects the system performance, rather than as a system consisting of small independent parts such as a sensor or an amplifier that could be designed separately. The objective of this doctoral dissertation is to describe in depth the development of the measurement system taking into account the challenges caused by the electrical and mechanical requirements and the measurement environment. The work is done as an empirical case study in two example applications that are both intended for scientific studies. The cases are a light sensitive biological sensor used in imaging and a gas electron multiplier detector for particle physics. The study showed that in these two cases there were a number of different parts of the measurement system that interacted with each other. Without considering these interactions, the reliability of the measurement may be compromised, which may lead to wrong conclusions about the measurement. For this reason it is beneficial to conceptualize the measurement system as a whole from the physical phenomena to the digital recording device where each piece of the measurement system affects the system performance. The results work as examples of how a measurement system can be successfully constructed to support a study of sensors and electronics.

Spectrally Tuned Lanthanide Photoluminescence for Point-of-Care Testing

Point-of-care (POC) –diagnostics is a field with rapidly growing market share. As these applications become more widely used, there is an increasing pressure to improve their performance to match the one of a central laboratory tests. Lanthanide luminescence has been widely utilized in diagnostics because of the numerous advantages gained by the utilization of time-resolved or anti-Stokes detection. So far the use of lanthanide labels in POC has been scarce due to limitations set by the instrumentation required for their detection and the shortcomings, e.g. low brightness, of these labels. Along with the advances in the research of lanthanide luminescence, and in the field of semiconductors, these materials are becoming a feasible alternative for the signal generation also in the future POC assays. The aim of this thesis was to explore ways of utilizing time-resolved detection or anti-Stokes detection in POC applications. The long-lived fluorescence for the time-resolved measurement can be produced with lanthanide chelates. The ultraviolet (UV) excitation required by these chelates is cumbersome to produce with POC compatible fluorescence readers. In this thesis the use of a novel light-harvesting ligand was studied. This molecule can be used to excite Eu(III)-ions at wavelengths extending up to visible part of the spectrum. An enhancement solution based on this ligand showed a good performance in a proof-of-concept -bioaffinity assay and produced a bright signal upon 365 nm excitation thanks to the high molar absorptivity of the chelate. These features are crucial when developing miniaturized readers for the time-resolved detection of fluorescence. Upconverting phosphors (UCPs) were studied as an internal light source in glucose-sensing dry chemistry test strips and ways of utilizing their various emission wavelengths and near-infrared excitation were explored. The use of nanosized NaYF :Yb3+,Tm3+-particles enabled the replacement of an external UV-light source with a NIR-laser and gave an additional degree of freedom in the optical setup of the detector instrument. The new method enabled a blood glucose measurement with results comparable to a current standard method of measuring reflectance. Microsized visible emitting UCPs were used in a similar manner, but with a broad absorbing indicator compound filtering the excitation and emission wavelengths of the UCP. This approach resulted in a novel way of benefitting from the non-linear relationship between the excitation power and emission intensity of the UCPs, and enabled the amplification of the signal response from the indicator dye.