UTUPub
Not a member yet
55238 research outputs found
Sort by
Partition-Tolerant and Byzantine-Tolerant Decision-Making for Distributed Robotic Systems with IOTA and ROS 2
No full textWith the increasing ubiquity of autonomous robotic solutions, the interest in their connectivity and in the cooperation within multi-robot systems is rising. Two aspects that are a matter of current research are robot security and secure multirobot collaboration robust to byzantine agents. Blockchain and other distributed ledger technologies (DLTs) have been proposed to address the challenges in both domains. Nonetheless, some key challenges include scalability and deployment within realworld networks. This paper presents an approach to integrating IOTA and ROS 2 for more scalable DLT-based robotic systems while allowing for network partition tolerance after deployment. This is, to the best of our knowledge, the first implementation of IOTA smart contracts for robotic systems, and the first integrated design with ROS 2. This is in comparison to the vast majority of the literature which relies on Ethereum. We present a general IOTA+ROS 2 architecture leading to partitiontolerant decision-making processes that also inherit byzantine tolerance properties from the embedded blockchain structures. We demonstrate the effectiveness of the proposed framework for a cooperative mapping application in a system with intermittent network connectivity. We show both superior performance with respect to Ethereum in the presence of network partitions, and a low impact in terms of computational resource utilization. These results open the path for wider integration of blockchain solutions in distributed robotic systems with less stringent connectivity and computational requirements.</p
Predicting context-sensitive urban green space quality to support urban green infrastructure planning
No full textUrban green spaces (UGSs) support human health and well-being in diverse ways. In addition to their availability and accessibility, also the quality of UGSs is relevant for understanding human-environment interactions between urban populations and their local UGS. However, data on UGS quality are rarely available with the geographic coverage required for spatial decision making and urban green infrastructure (UGI) planning and management.This study uses data from a large-scale public participation GIS (PPGIS) survey to predict perceived UGS quality across the city of Espoo, Finland. The respondents (n 3,132) mapped over 8,500 frequently visited sites situated in UGSs. Generalized linear mixed models were used to study associations between the perceived place quality of the respondent-mapped sites and diverse objectively measured UGS characteristics. The presence of blue elements, high forest biodiversity, level of UGS maintenance, and low daytime noise exposure contributed to positive perceptions of UGS quality, while daytime noise exposure and decreasing UGS size were associated with negative perceptions.The model was extrapolated spatially to predict perceived UGS quality across the entire city, revealing local differences in the accessibility of high-quality UGS. The results exemplify how both UGS quantity and quality are relevant for understanding the mechanisms leading to UGS visitation and the health and well-being benefits gained from UGS use and exposure. Moreover, the study demonstrates how UGS characteristics valued by the local population may be identified to support local UGI planning and management.</p
Searching for the stellar cycles of low-mass stars using TESS data
No full textWe carried out a search for stellar activity cycles in late low-mass M dwarfs (M0–M6) located in the TESS northern and southern continuous viewing zones using data from sectors 1–61 (Cycle 1 to partway through Cycle 5). We utilised TESS-SPOC data, which initially had a cadence of 30 min and was then reduced to 10 min in Cycle 3. In addition, we required for each star to be observed in at least six sectors in each north and south Cycle: 1950 low-mass stars ultimately met these criteria. Strong evidence was seen in 245 stars for a very stable photometric variation that we assumed to be a signature of the stars’ rotation period. We conducted a similar study for solar-like stars and found that 194 out of 1432 stars had a very stable modulation. We then searched for evidence of a variation in the rotational amplitude. We found 26 low-mass stars that showed evidence of variability in their photometric amplitude and only one solar-like star. Some display a monotonic trend over 3–4 years, whilst others reveal shorter term variations. We determined the predicted cycle durations of these stars using a relationship found in the literature and an estimate of the stars’ Rossby number. Finally, we found a marginally statistically significant correlation between the range in the rotational amplitude modulation and the rotation period.</p
Magnetospheric flows in X-ray pulsars – I. Instability at super-Eddington regime of accretion
No full textWithin the magnetospheric radius, the geometry of accretion flow in X-ray pulsars is shaped by a strong magnetic field of a neutron star. Starting at the magnetospheric radius, accretion flow follows field lines and reaches the stellar surface in small regions located close to the magnetic poles of a star. At low mass accretion rates, the dynamics of the flow is determined by gravitational attraction and rotation of the magnetosphere due to the centrifugal force. At the luminosity range close to the Eddington limit and above it, the flow is additionally affected by the radiative force. We construct a model simulating accretion flow dynamics over the magnetosphere, assuming that the flow strictly follows field lines and is affected by gravity, radiative, and centrifugal forces only. The magnetic field of a neutron star is taken to be dominated by the dipole component of arbitrary inclination with respect to the accretion disc plane. We show that accretion flow becomes unstable at high mass accretion rates and tends to fluctuate quasi-periodically with a typical period comparable to the free-fall time from the inner disc radius. The inclination of a magnetic dipole with respect to the disc plane and strong anisotropy of X-ray radiation stabilize the mass accretion rate at the poles of a star, but the surface density of material covering the magnetosphere fluctuates even in this case
Organisaation oppiminen sosiaali- ja terveydenhuolto-organisaatioissa – Kollektiivinen reflektio käytännön strategiatyössä
No full textThis research explores how collective reflection during strategizing supports organizational learning. Strategizing evolves over time as strategy practitioners interact with each other, use different strategy practices, and gain more experience of their strategy work. However, this learning process and the meaning of collective reflection within it has not been given attention in previous research. The theoretical frame of the study consists of strategy-as-practice (SAP), collective reflection, and organizational learning literature. In particular, the 4I-framework of organizational learning developed by Crossan et. al. (1999) is utilized. The empirical data were collected by a survey. According to the findings of the study, collective reflection during strategizing supports organizational learning, which, during strategizing, proceeds through microprocesses of intuition, interpretation, integration, and institutionalization. Furthermore, the study shows that the 4I model is suitable for scrutinizing organizational learning during strategizing.</p
Association of shivering threshold time with body composition and brown adipose tissue in young adults
No full textPurpose: Brown adipose tissue (BAT) increases metabolic heat production in response to cold exposure. Body size and composition are involved in the human cold response, yet the influence of BAT herein have not fully been explored. Here, we aimed to study the association of the cold-induced shivering threshold time with body composition, BAT, the perception of shivering and skin temperature in young adults. Methods: 110 young healthy adults (81 females; age = 21.7 +/- 2.1 years, BMI = 24.2 +/- 4.3 kg/m2) underwent 2 h of individualized cooling, followed by the quantification of BAT using a18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography-computed tomography (PET-CT) scan. Body mass index (BMI), lean mass, fat mass and body surface area (BSA) were also measured. Shivering threshold time was defined as the time until shivering occurred using an individualized cooling protocol. Results: The shivering threshold time was on average 116.1 min for males and 125.8 min for females, and was positively associated to BMI (beta = 3.106; R2 = 0.141; p = 0.001), lean mass (beta = 2.295; R2 = 0.128; p = 0.001) and fat mass (beta = 1.492; R2 = 0.121; p = 0.001) in females, but not in males (all p >= 0.409). The shivering threshold time was positively associated with BSA in males (p = 0.047) and females (p = 0.001), but it was not associated with BAT volume or [18F]FDG uptake nor with the perception of shivering and skin temperature perception in both sexes. Conclusion: The shivering threshold time is positively associated with whole-body adiposity and lean mass in females, but not in males. The shivering threshold time was positively associated with BSA, but no association was observed with BAT nor with the perception of shivering or skin temperature. Future research should consider the influence of body composition when applying cooling protocols among individuals with different phenotypical features
Anti-Apoptotic and Pro-Apoptotic Bcl-2 Family Proteins in Peri-Implant Diseases
No full textObjectivesIntrinsic apoptosis, which is regulated by Bcl-2 family proteins, has an important role in chronic inflammatory diseases. The aim of the study was to identify the tissue levels and ratios of anti- and pro-apoptotic Bcl-2 family proteins in peri-implant diseases.Materials and MethodsTwenty-three individuals with peri-implant mucositis, 25 individuals with peri-implantitis, and 24 controls were included. The following clinical parameters were recorded: keratinized mucosa width, modified bleeding index, probing depth, modified plaque index, modified gingival index, and keratinized tissue thickness. Marginal alveolar bone assessments were performed by a software program. Granulation tissues were collected during treatments of peri-implant diseases. The control tissue samples were collected during the second stage of implant surgery. The tissue levels of Bcl-2 family pro-apoptotic (Bak, Bax, active caspase-3) and anti-apoptotic (Bcl-2, Bcl-xL, Mcl-1) proteins were determined by multiplex immunoassay method.ResultsThe pro-apoptotic proteins; Bak, Bax and anti-apoptotic proteins Bcl-2, Bcl-xL, Mcl-1 were detected significantly higher in controls compared with patients with peri-implant mucositis and peri-implantitis (p ConclusionOur findings indicate dysregulation of the Bcl-2 family proteins in peri-implant diseases. This unregulated response may disturb the homeostasis of peri-implant tissue.</p
Does Childcare Attendance Moderate the Associations Between Mother-Child Depressive Symptoms and Children’s Peer Victimization Experiences?
No full textPeer victimization experiences is suggested to play a mediating role in the transmission of depression symptoms between mothers and children. Childcare attendance has been found to reduce the association between mother and child depressive symptoms. However, it is not clear whether this protective effect unfolds via a reduction of peer victimization experiences in middle childhood. The aims of this study were to test (1) whether peer victimization in middle childhood mediated the association between exposure to maternal depressive symptomatology in early childhood and child depressive symptoms in late childhood, (2) whether childcare attendance moderate the direct associations between maternal depressive symptoms and children’s peer victimization experiences in middle childhood as well as depressive symptoms in late childhood and (3) whether childcare attendance moderates this mediated association. Data come from the Avon Longitudinal Study of Children and Parents (N = 5526) where exposure to maternal depressive symptoms and intensity of childcare attendance were assessed repeatedly during early childhood. Children’s peer victimization and depressive symptoms were self-reported at eight and 10 years of age, respectively. We used weighted structural equation modeling and found that the association between mothers and children’s depression was partially mediated by peer victimization. Childcare attendance did not moderate the indirect effect of maternal depression on child depressive symptoms via peer victimization. However, we found that for children who attended childcare, maternal depression was no longer associated child depressive symptoms in late childhood. In conclusion, peer victimization experiences partly explain the intergenerational transmission of depressive symptoms, but this mechanism is not altered by children’s childcare attendance. Future research should examine potential socio-emotional and school readiness mechanisms that may break the cycle of depressive symptomatology from mothers to children.</p
