936 research outputs found
RLPG: Reinforcement Learning Approach for Dynamic Intra-Platoon Gap Adaptation for Highway On-Ramp Merging
A platoon refers to a group of vehicles traveling together in very close
proximity using automated driving technology. Owing to its immense capacity to
improve fuel efficiency, driving safety, and driver comfort, platooning
technology has garnered substantial attention from the autonomous vehicle
research community. Although highly advantageous, recent research has uncovered
that an excessively small intra-platoon gap can impede traffic flow during
highway on-ramp merging. While existing control-based methods allow for
adaptation of the intra-platoon gap to improve traffic flow, making an optimal
control decision under the complex dynamics of traffic conditions remains a
challenge due to the massive computational complexity. In this paper, we
present the design, implementation, and evaluation of a novel reinforcement
learning framework that adaptively adjusts the intra-platoon gap of an
individual platoon member to maximize traffic flow in response to dynamically
changing, complex traffic conditions for highway on-ramp merging. The
framework's state space has been meticulously designed in consultation with the
transportation literature to take into account critical traffic parameters that
bear direct relevance to merging efficiency. An intra-platoon gap decision
making method based on the deep deterministic policy gradient algorithm is
created to incorporate the continuous action space to ensure precise and
continuous adaptation of the intra-platoon gap. An extensive simulation study
demonstrates the effectiveness of the reinforcement learning-based approach for
significantly improving traffic flow in various highway on-ramp merging
scenarios
Interionic Pair Potential, hard sphere diameter and entropy of mixing of NaCd compound forming binary molten alloys under the framework of Pseudopotential theory
The observed asymmetric behaviour of mixing of NaCd liquid alloys around equiatomic composition with smaller negative values for free energy of mixing at compound forming concentration, i.e. GMXS = -4.9KJ at Ccd =0.66 has aroused our interest to undertake a theoretical investigation of this system.A simple statistical mechanical theory based on compound formation model has been used to investigate the energetics of formation of intermetallic compound Cd2Na in the melt through the study of entropy of mixing.Besides, the interionic interactions between component atoms Na and Cd of the alloys have been understood through the study of interionic pair potential фij(r), calculated from pseudopotential theory in the light of CF model.Our study of фij(r) suggest that the effective interaction between Na-Na atoms decreases on alloying with Cd atom, being minimum for compound forming alloy( Cd 0.66 Na 0.34 ).The nearest neighbor distance between Na-Na atoms does not alter on alloying. Like wise Na-Na, effective interaction between Cd-Cd atom decreases from pure state to NaCd alloys, being smaller at compound forming concentration Cd 0.66 Na 0.34.The computed values of SM from pseudopotential theory are positive at all concentrations, but the agreement between theory and experimental is not satisfactory. This might be happening due to parameterisation of σ3 and Ψcompound
Evaluation of endometrial thickness with transvaginal ultrasonography in perimenopausal women presenting with abnormal uterine bleeding and correlation with its histopathological findings
Background: Abnormal uterine bleeding is the most common presenting menstrual complaint in women of perimenopausal age group. Most frequently used diagnostics tests to investigate the causes of abnormal bleeding are Transvaginal ultrasonography (TVS) and endometrial biopsy. Uterine curettage is an invasive procedure and is performed with anaesthesia. TVS is a non-invasive method that has been used to evaluate the endometrium and uterine cavity. The objectives of this study were to measure and evaluate the role and accuracy of endometrial thickness by transvaginal ultrasonography study to detect endometrial pathology in perimenopausal women presenting with Abnormal Uterine Bleeding. To correlate the transvaginal sonographic results with the Histopathological findings to discriminate normal from pathological endometrium.Methods: Prospective study including 150 perimenopausal women with abnormal uterine bleeding. Endometrial thickness was measured by TVS and then D and C was performed for all the patients.Results: Out of 150 women, 128 (85.3%) had normal and 22 (15%) had an abnormal endometrium. 43.3% were of 41-45 years and 65.3% patients presented with complaint of heavy menstrual bleeding. Majority of the patients in the study group were para 2 or more. Fibroid uterus (24%) was the commonest uterine pathology detected on TVS. 53.3% of patients had endometrial thickness in the range 10-14.9 mm. Most common finding on HPE was secretory endometrium (44.6%). Endometrial carcinoma was found in 3%. Endometrial thickness <14mm was associated with least abnormal endometrial pathology.Conclusions: Endometrial thickness of less than 14 mm need not be indicated for D and C in perimenopausal abnormal uterine bleeding. In perimenopausal women with AUB, TVS should be the investigation of choice due to its convenience, accuracy and non- invasiveness
Pulmonary function status of refractory workers in a steel plant: A cross-sectional study design
Background: A lot of dust is generated during various operations in the refractory section of a steel plant. Refractory bricks contain chemicals such as aluminum, silica, magnesium, chromium, dolomite and tar. During walk-through surveys in the steel-making shop, we found refractory workers chronically exposed to occupational dust, but rarely using face masks. Most took chewable tobacco, yet none gave a history of any chronic complaint of a respiratory nature. Aims: To assess the pulmonary function of refractory workers in a steel plant using spirometry; determine the variability of ventilatory impairment across work sections; and test the association between pulmonary function and years of exposure.
Methods: We carried out a cross-sectional study from November to December 2016 in the refractory area of a steel-making shop, part of an integrated steel plant, in eastern India. Dust was measured in the ambient air at the shop floor level during entire shifts on three consecutive days by gravimetric method. Parameters measured included total suspended particulate matter (TSPM) and particles with a diameter of less than 10μm (PM10). The all-male workforce consisted of masons and non-masons. Of a total of 70 workers, 35, comprising 11 masons and 24 non-masons, were selected by simple random sampling. Spirometry and peak expiratory flow (PEF) measurements were carried out as per standard guidelines. Data were analyzed using the statistical software Statistica, Version 13.
Results: Geometric means of TSPM and PM10 were 2,928.35 and 839.04µg/m³, respectively. Ventilatory impairment was found in 14 (40%) of the workers. Of these 14 workers, impairment was chiefly obstructive in nature – in 11 workers (78.57%). The severity of defects were mainly of a mild type – 71.43% (10 workers). In the work area where non-masons worked, ventilatory impairment was 50% (12 workers); where masons worked, the proportion was 18.18% (two workers). Regression analysis showed a significant relationship between pulmonary function deterioration and years of work in the refractory area (P = 0.0038). Conclusions and recommendations: In our study, we found ventilatory impairment in refractory workers in a steel plant to be mainly of obstructive type and mild in severity. Pulmonary function deterioration was significantly (P < 0.01) affected by years of exposure. Ethiop .J. Health Dev. 2019; 33(4):203-211]
Key words: Pulmonary function, refractory workers, steel industry, exposure, spirometry, ventilatory impairment, obstructive defec
Effect of heating rates on the synthesis of Al2O3–SiC composites by the self-propagating high-temperature synthesis (SHS) technique
Various aspects of insitu formation of Al2O3–SiC composites by the self-propagating high-temperature synthesis (SHS) technique have been investigated using thermal analyses (TG/DTA) of a powder mixture (4Al, 3SiO2, 3C) and pellets in an argon atmosphere at different heating rates. Both the reaction initiation and peak temperatures are found to increase with the heating rates. At lower heating rates, the powder samples do not reveal any exothermic peak possibly because of poor reactivity and sluggish exothermic reaction. The appearance of exothermic peaks in the DTA plots after melting of aluminum indicates reduction of silica by liquid aluminum. Conversion of aluminum is found to decrease marginally with an increase in heating rates. The apparent activation energy of the process compares well with the interdiffusion activation energy of silicon and oxygen, indicating that oxygen diffusion in Si formed at the reaction front may be the rate-controlling factor for this SHS process. From SEM studies it appears that the formation of SiC whiskers is through liquid-phase mass transfer
Accordion Effect During Percutaneous Coronary Intervention (Pci)
Pseudo lesions appear in a coronary artery during intervention due to guide wire manipulation are referred as “accordion phenomenon” and are infrequent occurrences during percutaneous coronary intervention of tortuous coronary arteries. Occurrence of pseudo lesion or accordion phenomena puts a diagnostic challenge to the interventionist and might leads to unnecessary intervention. The differential diagnosis includes coronary dissection, thrombus and its spasm. Ischemia & hemodynamic compromise are possible complications. The common method to overcome this situation is pulling the guide wire out of the affected segments and leaving aside only the floppy segment. Pseudo lesion at times response to intracoronary nitro-glycerine however, sometimes they are refractory. We hereby report a case of Accordion phenomenon during PCI of right coronary artery & technical challenges it imposed on
A Comprehensive Overview Of Biological Aspects Of Plasmodium Knowlesi
Plasmodium knowlesi, originally known to cause simian malaria, is now recognized as the fifth human malarial parasite; in addition to P. vivax, P.alciparum, P. malariae & P. ovale. It is predominant in South East (SE) Asian Countries like Malaysia, Indonesia, Thailand, Cambodia, Vietnam, Myanmar, Singapore, Brunei, and Philippines. However, until recently, its prevalence was miniscule in India. A recent report from Andaman and Nicobar Islands, India, revealed presence of P. knowlesi-specific gene sequences in 53 out of 445 cases scanned for malarial parasites. The life cycle of the parasite, like its other counterparts, requires infection of both a mosquito and a warm-blooded host. The present review provides a detailed overview of the parasite, its life cycle, prevalence and its comparisons with other Plasmodium species. In addition, a comparison is drawn at the genomic and genetic level to provide an in-depth understanding of the parasite’s unique characteristics. The cyto-adhering properties and antigenic variants of Plasmodium knowlesi are also discussed
Characterisation of anaemia amongst school going adolescent girls in rural Haryana, India – CORRIGENDUM
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