113 research outputs found
Improvement of the Autodriver Algorithm for Autonomous Vehicles Using Roll Dynamics
The autodriver algorithm was introduced as a path-following algorithm for autonomous vehicles, which uses road geometry data and planar vehicle dynamics. In this paper, the autodriver algorithm is improved according to practical implications, and a more realistic vehicle model (roll mode) is used, which considers roll degree of freedom in addition to a planar motion. A Ghost-Car path-following approach is introduced to define the desired location of the car at every instance. Key steady-state characteristics of turning vehicles, namely the curvature, yaw rate, and side-slip responses, are discussed and used to construct a feed-forward component of a path-following controller based on the autodriver algorithm. Feedback control loops are designed and applied to minimise transient errors between the road and vehicle positions. Finally, simulations are performed to analyse the path-following performance of the proposed scheme. The results show promising performance of the controller both in terms of error minimisation and passenger comfort
Application of the mathematical autodriver algorithm for autonomous vehicles
The mathematical theory for autonomous vehicles, which was initially developed for 4 Wheel steering vehicles was formulated to work for 2 wheel steering vehicles as well. This was the first step towards making the theory closer to practice. Then a sample road using clothoids as the transition curve was generated. Clothoid was used as the best transition curve according to the literature for mobile robots trajectory generation. This study ended up in development of a design chart which could be used for better road design. The sample road is used to find the kinematic steering angles required by the vehicle to stay on the road. The kinematic steering angles work well only at very low forward velocities. The dynamic differential equations of motion of the vehicle needed to be solved to make the study of motion of the vehicle possible in higher velocities. During high forward velocity travelling some factors will cause the vehicle to move on a road different to the desired path of motion. The sample road generated proved that the traditional method of solving differential equations of motion was not very effective especially in the case of complicated mathematical paths of motion. That is why a new method was sought for, which resulted in the generation of the Steady-State Dynamic Steering method. This method provides an alternative way of studying the dynamics of motion of a vehicle, which is proved to be much faster and less complicated than the traditional method. At the end the new method was, put in to test by trying different vehicle travelling manoeuvres. After validation of the new method it was used mathematically to take control of a car to travel a sample desired path of motion autonomously by using the mathematical theory of autonomous vehicles
Autonomous Vehicles: Autodriver Algorithm and Vehicle Dynamics
A given road can be expressed mathematically in a global (or world) coordinate frame. Following the road can be substituted by following the loci of its curvature center and turning at the right circle of curvature. Considering that a vehicle in motion is always in turn about an instantaneous rotation center relative to the ground, an autonomous vehicle capable of following a given path by coinciding the rotation center of vehicle at every moment on the curvature center of the road could be designed. The dynamic reactions of the vehicle influence its path of motion and make its rotation center to depart from the desired path of the curvature center of the road. In this study, the Autodriver algorithm control strategy to front-wheel-steering vehicles has been developed and a control loop is introduced to compensate the present errors generated by the differences of the desired locating on the road and the real position of the vehicle
The Effect Of Nano-Zinc Oxide On Particleboard Decay Resistance
The aim of this study was to investigate the decay resistance of particleboards treated with nano-zinc oxide against the white-rot fungus Trametes versicolor and the brown-rot species Coniophora puteana. The nanomaterial was used for manufacturing particleboards at 5, 10 and 15% wt based on the glue dry weight. The soil block decay test was performed according to ASTM D 1413 (2007) using a 12 weeks incubation period. The results showed that all treated boards had good resistance against the decay fungi and the weight loss decreased in the samples with increasing nanomaterial loading. The threshold level of treated boards against fungal decay was obtained about 21% and 17% nano-ZnO against C. puteana and T. versicolor, respectively. Therefore, it had a positive effect on increasing particleboard resistance against the fungi. The maximum decay resistance (or minimum weight loss) occurred in the samples containing 15% zinc oxide nanoparticles
Dietary patterns, nutrition, and risk of breast cancer: a case-control study in the west of Iran
OBJECTIVES Unhealthy dietary patterns are the most important changeable risk factors for breast cancer. The aim of this study was to assess the relationship between dietary patterns and the risk of breast cancer among under-50 year women in the west of Iran. METHODS All women under 50 years old with pathologically confirmed breast cancer between 2013 and 2015 who were referred to oncology clinics in the west of Iran, and 408 under-50 women referred to other outpatient clinics who were without breast or other cancers at the time of the study and 2 years later were selected as the control group. The data were collected using the middle-aged periodical care form of the Iranian Ministry of Health and analyzed using univariate and multivariate logistic regression in Stata. RESULTS The most powerful risk factor for breast cancer was fried foods; the odds ratio of consuming fried foods more than once a month for breast cancer was 4.5 (95% confidence interval, 2.1 to 9.4). A dose-response model indicated that increasing vegetable and fruit consumption up to 90 servings per month decreased the odds of breast cancer, but consuming more than 90 servings per month increased the risk. CONCLUSIONS Inadequate consumption of vegetables and consumption of soft drinks, industrially produced juices, fried foods, and sweets were identified as risk factors for breast cancer. In response to these findings, it is necessary to raise awareness and to provide education about healthy diets and the need to change unhealthy dietary patterns
The effect of moisture content on the retention and distribution of nano-titanium dioxide in the wood
When chemically treating wood products is used to enhance the properties, the distribution of chemicals in the wood can be more important than the amount of chemical uptake. In this research, two moisture contents (MC) (0 and 25%) were used to study the effect of MC on the nanomaterial retention and distribution in cottonwood (Populus deltoides) sapwood treated with nano-titanium dioxide. The wood samples were impregnated by a full-cell process at three levels of nano-TiO2 concentration: 0,5; 1 and 1,5%. The nanomaterial retention was calculated and SEM images were used to investigate the distribution of nanoparticles in the wood. The results showed that increasing the nano-TiO2 concentration caused more retention and the MC difference caused almost identical retention at 0,5 and 1% concentrations. Although the retention in the 0% MC samples was slightly more than those of 25% MC, this retention was significantly more in these samples (0% MC) at 1,5% concentration. SEM images indicated that the nanoparticles had more uniform distribution in the 0% MC samples than the 25% MC ones and the difference was clearly visible at 1,5% concentration. Low MC ranges (about 0%) are better than high MCâs to impregnate cottonwood samples with nano-TiO2 by using the full-cell process
An Investigation on the possibility of utilization of chemical material for mitigation of Cochlodinium sp. bloom and their impact on the Litopenaeus vannamei shrimp
Cochlodinium polykrikoides is a common red tide former associated with fish kills in the most coastal waters of the world. Pay attention red tide problems to human and environment, forecast and control of algal bloom are aim of a lot of coastal environmental studies. Following Cochlodinium polykrikoideswas bloom in Oman Sea and Persian Gulf, extensive mortality of aquatic animal were seen in 2008, instances verified extensive damaged to wetland habitats during algal bloom. In this study have been tried for finding a suitable chemical composition for Mitigation of Cochlodinium polykrikoides bloom in wetlands. To identify the safe chemical substance against red tide in coastal waters wetlands, concentration effects of 0.01 mg/l, 0.04 mg/l, 0.4 mg/l, 1 mg/l and 1 gr/l Magnesium Hydroxide, Poly Aluminum Chloride (PAC), Aluminum Sulfate, Sodium Hypochlorite, Calcium Carbonate, Ferrous Sulfate, Starch on Laboratory cultures of Cochlodinium polykrikoides (1000000 cell/lit) and Litopenaeus vannamei were studied in Iranian Shrimp research center. Cochlodinium polykrikoides were cultured under a cool white fluorescent light of 2000 lux intensity with a 12:12 h light: dark cycle. Temperature and salinity were controlled 28 °C and of 30 g/l (ppt), respectively. Finding show that, all concentration of above substance, completely disintegrated of cultured Cochlodinium polykrikoides. Also except 1 g/l Sodium Hypochlorite, in other concentrations of studied substances, there werenât seen shrimp mortality after 96h. Among studied substance, starch have limit effects on the shrimp health and environment, therefore it can be suitable for controlling of Cochlodinium polykrikoides in shrimp ponds
Concurrent SPECT/PET-CT imaging as a method for tracking adoptively transferred T-cells in vivo
Nursing Presence Enhancement Using the CALM Scale for Pain Assessment in Laboring Women
Background: Pain is associated with negative patient outcomes and dissatisfaction. The use of the Numerical Rating Scale (NRS) has not improved patient outcomes in laboring women. The NRS fails to account for several factors that influence pain. Nursing presence is defined as being physically available, emotionally supportive, and advocating for the woman during childbirth. Nursing presence positively influences the pain experience of laboring women. The Coping Assessment in Laboring Moms (CALM) scale was created to address the multifaceted aspects of labor pain and promote nurse presence. Purpose: To implement a change in practice for assessing pain during labor in a labor and delivery unit in a southeastern U.S. Womenâs Hospital. The project aims to identify the need for change in practice using the CALM scale. Methods: The CALM scale was implemented in the Labor and Delivery Unit after an educational intervention was presented. HCAHPS scores for nurse care were compared during the NRS scale use and during the use of the CALM scale. A survey given to nurses assessed their perceived nursing presence after using the CALM scale. Results: Although patient HCAHPS surveys did not identify a significant difference in nursing presence between the two pain assessments, nursing presence surveys administered to the labor and delivery nurses revealed 64.29% found the CALM scale enhanced nursing presence. Recommendations and Conclusion: Differences in the HCAHPS survey results were not significant. Future studies may consider another instrument to assess nursing presence or a longer period for data collection. The nurse survey results demonstrated evidence of increased nursing presence when the CALM scale was used supporting results from previous studies
A survey on the effect of Cochlodinium.sp bloom on shrimp culture complexes and hatcheries activities in Bushehr Province
The aims of this project was to inform and aware about the red tide condition before entering the algal bloomer in water resources to the hatcheries and farmed shrimp complexes in Bushehr province coastal. Field investigation and sampling have been carried out in the southern of the input water channels of Mond, Delvar and Helleh farmed shrimp complexes, which are located along the coastal of Bushehr Province, from April to December 2011 .The physic-chemical parameters such as pH, salinity and water temperature and also meteorological conditions were measured and recorded on the field. The water sampling has been lunched for determination of nutrients and chlorophyll - a, phyto- and zoo- planktons. No Cochlodinium.sp outbreaks have been detected in the studied area, during the study. The only bloom which reported by a fisherman, was outbreak in offshore of Bushehr province in Khoure Khan on 13th September 2011. The sample which transferred to the Iranian National Shrimp Research Institute was included Alexandrium.sp and its density was 2 million cells per liter. The identified phytoplanktons were belonged to three order of Bacillariophyceae (52.6%) with average density of 10778 cells per liter, Dinophyceae (37.7%) with density of 7731 cells per liter and Cyanophyceae (9.7%) with density of 1980 cells. 12 genera belonged to Dinophyceae , 25 genera of Bacillariophyceae and two genera of Cyanophyceae were observed during the study. The highest density of phytoplankton was recorded in Helleh station by 18374 cells per liter. The maximum density of phytoplankton was at Delvar station by 141120 cells per liter in December. The highest density of the phytoplanktons was belonged to Dinophyceae by 126000 by cells per liter of which the Alexandrium.sp had the density of 124500 cells per liter in August 2011. From the Dinophyceae the Alexandrium.sp with mean density of 20345 cells per liter, Ornithocercus 920 cells and Prorocentrum.sp 820 cells were the predominant species. The identified Zooplankton in were belonged to 8 branches and 19 groups. The highest density of zooplankton was recorded in Helleh station by 1194 no. per liter. Nauplii were the dominant zooplankton groups with an average density of 136.4 no. per liter, Tintinnids 98.7, Cyclopoida 60.8, Calanoida 35.7 and Harpacticoids 14.5 no. per liter . The average of water and air temperature was recorded 29.4 °C and 28.3 °C, respectively. Average of salinity was 41.2 and pH was 8.46. The average of depth in all stations was 5.7 m. The mean concentrations of silicate, nitrate, nitrite, ammonia and total phosphate were 1.99, 0.03, 0.009, 0.14 0.15 ppm, respectively and the average of chlorophyll - a was 0.94 mg.m-3
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