500 research outputs found
Achieving Secure and Efficient Cloud Search Services: Cross-Lingual Multi-Keyword Rank Search over Encrypted Cloud Data
Multi-user multi-keyword ranked search scheme in arbitrary language is a
novel multi-keyword rank searchable encryption (MRSE) framework based on
Paillier Cryptosystem with Threshold Decryption (PCTD). Compared to previous
MRSE schemes constructed based on the k-nearest neighbor searcha-ble encryption
(KNN-SE) algorithm, it can mitigate some draw-backs and achieve better
performance in terms of functionality and efficiency. Additionally, it does not
require a predefined keyword set and support keywords in arbitrary languages.
However, due to the pattern of exact matching of keywords in the new MRSE
scheme, multilingual search is limited to each language and cannot be searched
across languages. In this pa-per, we propose a cross-lingual multi-keyword rank
search (CLRSE) scheme which eliminates the barrier of languages and achieves
semantic extension with using the Open Multilingual Wordnet. Our CLRSE scheme
also realizes intelligent and per-sonalized search through flexible keyword and
language prefer-ence settings. We evaluate the performance of our scheme in
terms of security, functionality, precision and efficiency, via extensive
experiments
Whole-body Dynamic Collision Avoidance with Time-varying Control Barrier Functions
Recently, there has been increasing attention in robot research towards the
whole-body collision avoidance. In this paper, we propose a safety-critical
controller that utilizes time-varying control barrier functions (time varying
CBFs) constructed by Robo-centric Euclidean Signed Distance Field (RC-ESDF) to
achieve dynamic collision avoidance. The RC-ESDF is constructed in the robot
body frame and solely relies on the robot's shape, eliminating the need for
real-time updates to save computational resources. Additionally, we design two
control Lyapunov functions (CLFs) to ensure that the robot can reach its
destination. To enable real-time application, our safety-critical controller
which incorporates CLFs and CBFs as constraints is formulated as a quadratic
program (QP) optimization problem. We conducted numerical simulations on two
different dynamics of an L-shaped robot to verify the effectiveness of our
proposed approach
The level of circulating endothelial progenitor cells may be associated with the occurrence and recurrence of chronic subdural hematoma
OBJECTIVES: The onset of chronic subdural hematoma may be associated with direct or indirect minor injuries to the head or a poorly repaired vascular injury. Endothelial progenitor cells happen to be one of the key factors involved in hemostasis and vascular repair. This study was designed to observe the levels of endothelial progenitor cells, white blood cells, platelets, and other indicators in the peripheral blood of patients diagnosed with chronic subdural hematoma to determine the possible relationship between the endothelial progenitor cells and the occurrence, development, and outcomes of chronic subdural hematoma. METHOD: We enrolled 30 patients with diagnosed chronic subdural hematoma by computer tomography scanning and operating procedure at Tianjin Medical University General Hospital from July 2009 to July 2011. Meanwhile, we collected 30 cases of peripheral blood samples from healthy volunteers over the age of 50. Approximately 2 ml of blood was taken from veins of the elbow to test the peripheral blood routine and coagulation function. The content of endothelial progenitor cells in peripheral blood mononuclear cells was determined by flow cytometry. RESULTS: The level of endothelial progenitor cells in peripheral blood was significantly lower in preoperational patients with chronic subdural hematomas than in controls. There were no significant differences between the two groups regarding the blood routine and coagulation function. However, the levels of circulating endothelial progenitor cells were significantly different between the recurrent group and the non-recurrent group. CONCLUSIONS: The level of circulating endothelial progenitor cells in chronic subdural hematoma patients was significantly lower than the level in healthy controls. Meanwhile, the level of endothelial progenitor cells in recurrent patients was significantly lower than the level in patients without recurrence. Endothelial progenitor cells may be related to the occurrence and recurrence of chronic subdural hematoma
Geometric Projectors: Geometric Constraints based Optimization for Robot Behaviors
Generating motion for robots that interact with objects of various shapes is
a complex challenge, further complicated when the robot's own geometry and
multiple desired behaviors are considered. To address this issue, we introduce
a new framework based on Geometric Projectors (GeoPro) for constrained
optimization. This novel framework allows for the generation of task-agnostic
behaviors that are compliant with geometric constraints. GeoPro streamlines the
design of behaviors in both task and configuration spaces, offering diverse
functionalities such as collision avoidance and goal-reaching, while
maintaining high computational efficiency. We validate the efficacy of our work
through simulations and Franka Emika robotic experiments, comparing its
performance against state-of-the-art methodologies. This comprehensive
evaluation highlights GeoPro's versatility in accommodating robots with varying
dynamics and precise geometric shapes. For additional materials, please visit:
https://www.xueminchi.com/publications/geoproComment: 9 pages, 5 figure
Optimization-Based Motion Planning for Autonomous Parking Considering Dynamic Obstacle: A Hierarchical Framework
We present a hierarchical framework based on graph search and model
predictive control (MPC) for electric autonomous vehicle (EAV) parking
maneuvers in a tight environment. At high-level, only static obstacles are
considered, and the scenario-based hybrid A* (SHA*), which is faster than the
traditional hybrid A*, is designed to provide an initial guess (also known as a
global path) for the parking task. To extract the velocity and acceleration
profile from an initial guess, an optimal control problem (OCP) is built. At
the low level, an NMPC-based strategy is used to avoid dynamic obstacles (also
known as local planning). The efficacy of SHA* is evaluated through 148
different simulation schemes and the proposed hierarchical parking framework is
demonstrated through a real-time parallel parking simulation
Disability-Free Life Expectancy among People Over 60 Years Old by Sex, Urban and Rural Areas in Jiangxi Province, China
Objective: To estimate and compare age trends and the disability-free life expectancy (DFLE) of the population over 60 years old in 2018 in Jiangxi Province, China, by sex and urban–rural areas. Methods: The model life table was employed to estimate the age-specific mortality rate by sex and urban–rural areas, based on the Summary of Health Statistics of Jiangxi Province in 2018 and the Sixth National Health Service survey of Jiangxi Province. DFLE and its ratio to life expectancy (LE) were obtained by the Sullivan method. Results: In 2018, the DFLE among people over 60 is 17.157 years for men and is 19.055 years for women, accounting for 89.7% and 86.5% of their LE respectively. The DFLE/LE of men is higher than that of women at all ages. LE and DFLE are higher for the population in urban areas than in rural areas. For women, DFLE/LE is higher in urban areas than in rural areas (except at ages 75 and 80). Urban men have a higher DFLE/LE than rural men (except at age 85). The difference in DFLE between men and women over 60 years is 1.898 years, of which 2.260 years are attributable to the mortality rate, and 0.362 years are due to the disability-free prevalence. In addition, the difference in DFLE between urban–rural elderly over 60 years old is mostly attributed to the mortality rate by gender (male: 0.902/1.637; female: 0.893/1.454), but the impact of the disability-free rate cannot be ignored either (male: 0.735/1.637; female: 0.561/1.454). Conclusions: The increase in DFLE is accompanied by the increase in LE, but with increased age, DFLE/LE gradually decreases. With advancing age, the effect of disability on elderly people becomes more severe. The government administration must implement some preventive actions to improve health awareness and the life quality of the elderly. Rural elderly; rural women in particular, need to be paid more attention and acquire more health care
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