This paper addresses the asymptotic dynamic positioning of ships in the presence of actuator constraints and partial loss of actuator effectiveness faults. A simple saturated proportional-derivative ...controller is proposed. Lyapunov direct method is employed to prove asymptotic stability. Explicit conditions on control gains for ensuring asymptotic stability are presented. Advantages of the proposed controller include simple and intuitive structure, high computation efficiency, and absence of modeling parameter and fault detection and isolation mechanism in the control law formulation, and thus it is ready to implement. An additive appealing feature is that the proposed controller has the abilities to protect the actuator from control effort saturation and compensate the partial loss of actuator effectiveness faults. An illustrative example is presented to demonstrate the effectiveness of the proposed approach.
In the current era of increasing urbanization, urban green spaces play a crucial role in enhancing human well-being. However, quantifying public perceptions from text data at spatio-temporal scales ...remains challenging, and the relationship between urban green space perception and spatial-physical attributes requires further exploration. This study systematically examines public perceptions of urban green spaces within Singapore's urban parks from 2018 to 2022. Utilizing Twitter data, it applies large language models to conduct textual content analysis related to urban green space. The findings reveal a positive trend, with individuals expressing favorable perceptions and satisfaction towards urban green spaces in Singapore. Specifically, this study demonstrates that people's perceptions of urban green spaces are influenced by vegetation density. Higher vegetation density heightens people's awareness of spatial presence, while shrub and grassland may lead to neglect of urban green spaces as individuals focus more on themselves. Additionally, due to the spatial heterogeneity of the area, there is no clear correlation between all land covers and public satisfaction with urban green spaces in Singapore. The results also indicate a significant decrease in public perception in 2020, followed by a subsequent recovery. This fluctuation is attributed to the substantial impact of the COVID-19 pandemic, suggesting that external socio-political, economic, and public health events can impact public green space needs and spatial perceptions. In conclusion, this study contributes to the understanding of urban green spaces by effectively analyzing textual content extracted from social media data using large language models. The insights gained contribute valuable to the following discussions regarding the planning and design of urban green spaces and urban parks.
•Large language models can be effectively utilized in urban spatial perception.•We assessed the overall perception of urban green spaces in Singapore.•The public perception of green spaces depends on vegetation density.•Social public events can influence people's perception of urban green spaces.
This paper addresses the problem of finite-time output feedback stabilization for the perturbed double integrator system. A simple output feedback proportional–derivative (PD) controller is proposed. ...Global finite-time stability is proven based on Lyapunov stability theory and geometric homogeneity technique. Furthermore, it is proven that the proposed controller can maintain local finite-time stability regardless of some nonlinear perturbations. Thus, the proposed controller actually can be applied to a large class of uncertain second-order nonlinear systems. Simulations demonstrate the effectiveness of the proposed approach.
It has recently been reported that intermittent fasting shapes the gut microbiota to benefit health, but this effect may be influenced to the exact fasting protocols. The purpose of this study was to ...assess the effects of different daily fasting hours on shaping the gut microbiota in mice. Healthy C57BL/6 J male mice were subjected to 12, 16 or 20 h fasting per day for 1 month, and then fed ad libitum for an extended month. Gut microbiota was analyzed by 16S rRNA gene-based sequencing and food intake was recorded as well.
We found that cumulative food intake was not changed in the group with 12 h daily fasting, but significantly decreased in the 16 and 20 h fasting groups. The composition of gut microbiota was altered by all these types of intermittent fasting. At genus level, 16 h fasting led to increased level of Akkermansia and decreased level of Alistipes, but these effects disappeared after the cessation of fasting. No taxonomic differences were identified in the other two groups.
These data indicated that intermittent fasting shapes gut microbiota in healthy mice, and the length of daily fasting interval may influence the outcome of intermittent fasting.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We report the generation of human ESC-derived, expandable hepatic organoids (hEHOs) using our newly established method with wholly defined (serum-free, feeder free) media. The hEHOs stably maintain ...phenotypic features of bipotential liver stem/progenitor cells that can differentiate into functional hepatocytes or cholangiocytes. The hEHOs can expand for 20 passages enabling large scale expansion to cell numbers requisite for industry or clinical programs. The cells from hEHOs display remarkable repopulation capacity in injured livers of FRG mice following transplantation, and they differentiate in vivo into mature hepatocytes. If implanted into the epididymal fat pads of immune-deficient mice, they do not generate non-hepatic lineages and have no tendency to form teratomas. We further develop a derivative model by incorporating human fetal liver mesenchymal cells (hFLMCs) into the hEHOs, referred to as hFLMC/hEHO, which can model alcoholic liver disease-associated pathophysiologic changes, including oxidative stress generation, steatosis, inflammatory mediators release and fibrosis, under ethanol treatment. Our work demonstrates that the hEHOs have considerable potential to be a novel, ex vivo pathophysiological model for studying alcoholic liver disease as well as a promising cellular source for treating human liver diseases.
Sweat glands perform a vital thermoregulatory function in mammals. Like other skin components, they originate from epidermal progenitors. However, they have low regenerative potential in response to ...injury. We have established a sweat gland culture and expansion method using 3D organoids cultures. The epithelial cells derived from sweat glands in dermis of adult mouse paw pads were embedded into Matrigel and formed sweat gland organoids (SGOs). These organoids maintained remarkable stem cell features and demonstrated differentiation capacity to give rise to either sweat gland cells (SGCs) or epidermal cells. Moreover, the bipotent SGO-derived cells could be induced into stratified epidermis structures at the air-liquid interface culture in a medium tailored for skin epidermal cells in vitro. The SGCs embedded in Matrigel tailored for sweat glands formed epithelial organoids, which expressed sweat-gland-specific markers, such as cytokeratin (CK) 18 and CK19, aquaporin (AQP) 5 and αATP. More importantly, they had potential of regeneration of epidermis and sweat gland when they were transplanted into the mouse back wound and claw pad with sweat gland injury, respectively. In summary, we established and optimized culture conditions for effective generation of mouse SGOs. These cells are candidates to restore impaired sweat gland tissue as well as to improve cutaneous skin regeneration.
Automated log parsing is essential for many log-mining applications, as logs provide a vast range of information on events and variations within an operating system or software at runtime. Over the ...years, various methods have been proposed for log parsing. With improved log-parsing methods, log-mining applications can gain deeper insights into system behaviors and identify anomalies or failures promptly. However, current log parsers still face limitations, such as insufficient parsing of log templates and a lack of parallelism, as well as inaccurate log template parsing. To overcome these limitations, we have designed Polo, a parser that leverages a prefix forest composed of ternary search trees to mine templates from logs. We then conducted extensive experiments to evaluate the accuracy of Polo on nine representative system logs, achieving an average accuracy of 0.987. It is 9.93% to 40.95% faster than the state-of-the-art parsing methods. Furthermore, we evaluated our approach on a downstream log analysis task, specifically anomaly detection. The experimental results demonstrated that, in terms of F1-score, our parser outperformed Deeplog, LogAnomaly, CNN, and LogRobust by 11.5%, 4%, 1%, and 19.1%, respectively, exhibiting a promising recall score of 0.971. These results indicate the effectiveness of Polo for anomaly detection.
The proof of Theorem 1 in Moulay et al., (2022) is flawed; thus, it is unclear whether the proposed controller in that paper is capable of achieving the claimed result.
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