Combination of altimetry data from different satellite missions

Substantial altimetry datasets collected by different satellites have only become available during the past five years, but the future will bring a variety of new altimetry missions, both parallel and consecutive in time. The characteristics of each produced dataset vary with the different orbital heights and inclinations of the spacecraft, as well as with the technical properties of the radar instrument. An integral analysis of datasets with different properties offers advantages both in terms of data quantity and data quality. This thesis is concerned with the development of the means for such integral analysis, in particular for dynamic solutions in which precise orbits for the satellites are computed simultaneously. The first half of the thesis discusses the theory and numerical implementation of dynamic multi-satellite altimetry analysis. The most important aspect of this analysis is the application of dual satellite altimetry crossover points as a bi-directional tracking data type in simultaneous orbit solutions. The central problem is that the spatial and temporal distributions of the crossovers are in conflict with the time-organised nature of traditional solution methods. Their application to the adjustment of the orbits of both satellites involved in a dual crossover therefore requires several fundamental changes of the classical least-squares prediction/correction methods. The second part of the thesis applies the developed numerical techniques to the problems of precise orbit computation and gravity field adjustment, using the altimetry datasets of ERS-1 and TOPEX/Poseidon. Although the two datasets can be considered less compatible that those of planned future satellite missions, the obtained results adequately illustrate the merits of a simultaneous solution technique. In particular, the geographically correlated orbit error is partially observable from a dataset consisting of crossover differences between two sufficiently different altimetry datasets, while being unobservable from the analysis of altimetry data of both satellites individually. This error signal, which has a substantial gravity-induced component, can be employed advantageously in simultaneous solutions for the two satellites in which also the harmonic coefficients of the gravity field model are estimated

Software business : A short history and trends for the future

During its 70 years of existence, the software business has been following an evolution curve that can be considered typical for several fields of industrial businesses. Technological breakthroughs and innovations are typically seen as enablers for business evolution in the domain of technology and innovation management. Software, data collection, and data analysis represent a greater and greater part of the value of products and services, and today, their role is also becoming essential in more traditional fields. This, however, requires business and technology competences that traditional industries do not have. The transformation also enables new ways of doing business and opens the field for new kinds of players. Together, all this leads to transformation and new possibilities for the software industry. In this paper we study the overall trajectory of the software business, and then offer some viewpoints on the change in different elements of business models. Copyright © by the paper's authors. Copying permitted only for private and academic purposes.Peer reviewe

Computers in Education

Computers, or in wider scope, information and communication technology (ICT), have had revolutionary impact on education. ICT is both merged to the education process and is supporting it. Computers and information technology are typical enabling technologies not in the focus itself, but when available, these are adopted in use. Performance of computers has grown exponentially: According to Moore's law processing power and RAM capacity is doubled in 1.5 years. The similar growth rate relates to mass memories and data transmission speed. During the era of computing (from the middle 1940s) information technology has gradually transferred to new areas of use. In the beginning, the computers themselves were in focus. In the 1970s microelectronics has been the key to changes: first personal computers, then networking and cloud technologies, further embedded intelligence of devices, distributed computing, complex software, wide access to heterogeneous data sources etc. have brought the computer to the growing number of applications, also in the education sector. The purpose of this paper is to have a look at the concept 'computers in education It has been the title of the conference track in Mipro over decades. It is widely handled in literature, journals, and other publications. These provide forum for experience transfer in the area, as well as encourage researchers to study the topic from the scientific direction. The paper is partially based on the experiences of the authors and aimed to clarify the term from a variety point of view.acceptedVersionPeer reviewe

IT Education in Clouds and Clouds in IT Education

The rapid development of information and communication technology (ICT) and growing participation of students in work life has already in several decades moved ICT education into 'clouds', using sources of knowledge on Internet from all around the world. The COVID pandemic has increased this process, forcing universities to restrict classroom teaching and rapidly increased student's self-study.At the same time, increase of amounts of data to be processed is constantly introducing new high-level software technologies, layers and layers of packages and libraries, deeper and more complex. This has created a new 'top-down' programming style: a new project is started with importing mass of libraries which have been used in earlier projects and only then is considered how to use them in order to solve the programming task. The self-studying ICT students see only tips of modern software icebergs and it is difficult for them to understand their working without face-to-face classroom communication where details of the 'depths' are explained.acceptedVersionPeer reviewe

Increased risk of heat stress conditions during the 2022 Comrades Marathon

The Comrades Marathon is South Africa’s – and the world’s – most recognised and largest ultra-marathon event, with over 15 000 participants from across the globe competing in the 89-km road running event each year. Historically, the event has been held before the start of austral winter (20 May – 17 June). However, in 2022, organisers of the race moved the event to 28 August, when austral spring commences. We explore the climate, in particular the Universal Thermal Comfort Index (UTCI), of past Comrades events (1980-2019) and compare these data to UTCI data of the new proposed date (28 August) for the same period. The climatology for May, June, July and August was determined to identify periods with the lowest risk for ‘strong’ to ‘very strong’ heat stress. Results show that participants’ risk of exposure to ‘strong’ heat stress and ‘very strong’ heat stress periods will be more likely if the event is held in August as compared to the original event dates. Therefore, it is concluded that mid-June to mid-July has the lowest risk of heat stress exposure along the route. Runners and organisers should be aware of the higher risk of exertional heat illness during the 2022 Comrades Marathon to ensure safe participation. Significance: • The new proposed date for the Comrades Marathon will increase the risk of exposure to ‘strong’ and ‘very strong’ heat stress conditions, as defined by the Universal Thermal Comfort Index (UTCI). • The UTCI indicates that mid-June to mid-July has the lowest risk of heat stress exposure at the three reference points along the route. • Organisers should warn runners of the higher risk of exertional heat illness due to the possible exposure to high UTCI values or more unfavourable climatological conditions. Furthermore, runners should be informed of a variety of preventative strategies to ensure safe participation

Clones with finitely many relative R-classes

For each clone C on a set A there is an associated equivalence relation analogous to Green's R-relation, which relates two operations on A iff each one is a substitution instance of the other using operations from C. We study the clones for which there are only finitely many relative R-classes.Comment: 41 pages; proofs improved, examples adde

Application des recommandations dans la prise en charge du cancer de l’endomètre en pratique clinique. Étude rétrospective bretonne

National audienceObjective - To assess the use of French Cancer Institute recommendations for the diagnosis and treatment of endometrial cancer. Methods - Retrospective observational study involving 137 patients with endometrial cancer between 2011 and 2013. Results - Both MRI and pathological assessment with correct report as recommended were used for 66.4% of patients with endometrial cancer. For patients with correct preoperative assessment, 44.9% of patients were uncorrectly classified and upgraded on final pathological analysis of hysterectomy concerning lymph node involvement risk. These patients did not have confident surgical assessment, according this risk. Conclusion - To improve relevance of preoperative assessment in endometrial cancer, radiological and pathological expertise is required. However, even performed optimally, preoperative assessment does not allow correct risk stratification of lymph node involvement in endometrial cancer. This ineffective stratification leads to propose sentinel lymph node biopsy with hysterectomy in case of preoperative low risk endometrial cancer assessment

Space User Visibility Benefits of the Multi-GNSS Space Service Volume: An Internationally-Coordinated, Global and Mission-Specific Analysis

The number and scope of Global Navigation Satellite System (GNSS)-based space applications has grown significantly since the first GNSS space receiver was flown in the early 1980's. The vast majority of GNSS space users operate in Low-Earth Orbit (LEO), where the use of GNSS receivers has become routine. However, the use of GNSS has expanded to other orbit regimes like Geostationary Orbits (GEO) and High Eccentric Orbits (HEO) but has been very limited due to the challenges involved. The major challenges for such types of orbits including much weaker signals, reduced geometric diversity, and limited signal availability. In any case, considering the recent development of multiple GNSS constellations and ongoing upgrades to existing constellations, GNSS signal availability will improve significantly. As a result, this expanded multi-GNSS signal capability will enable improved on-orbit navigation performance and will also allow the development of new mission concepts. High altitude space users will especially benefit from this evolution, which will provide GNSS signals to challenging regimes well beyond Low Earth Orbit. These benefits will only be realised, however, if additional signals are designed to be interoperable, are clearly documented and supported. In order to enhance the overall GNSS performance for spacecraft's in regimes from LEO, GEO to HEO and beyond, all Satellite Navigation constellation providers and regional augmentation system providers are working together through the United Nations International Committee on GNSS (ICG) forum to establish an interoperable GNSS Space Service Volume (SSV) for the benefit of all GNSS space users. This paper provides an overview of the technical work and in particular the simulations, performance analysis and discussions of the outcomes and results obtained by the UN ICG Working Group-B in the context of the GNSS Space Service Volume activities, which were supported by all GNSS service providers

Seasonal variations of Saanen goat milk composition and the impact of climatic conditions

The aim of this research was to investigate the effect of climatic conditions and their impact on seasonal variations of physico-chemical characteristics of Saanen goat milk produced over a period of 4 years. Lactation period (early, mid and late) and year were considered as factors that influence physico-chemical composition of milk. Pearson's coefficient of correlation was calculated between the physico-chemical characteristics of milk (fat, proteins, lactose, non-fat dry matter, density, freezing point, pH, titrable acidity) and climatic condition parameters (air temperature, temperature humidity index-THI, solar radiation duration, relative humidity). Results showed that all physico-chemical characteristics of Saanen goat milk varied significantly throughout the lactation period and years. The decrease of fat, protein, non-fat dry matter and lactose content in goat milk during the mid-lactation period was more pronounced than was previously reported in the literature. The highest values for these characteristics were recorded in the late lactation period. Observed variations were explained by negative correlation between THI and the physico-chemical characteristics of Saanen goat milk. This indicated that Saanen goats were very prone to heat stress, which implied the decrease of physico-chemical characteristics during hot summers