57 research outputs found
Opponent Modeling in Automated Bilateral Negotiation: Can Machine Learning Techniques Outperform State-of-the-Art Heuristic Techniques?
No full textAutomated negotiation agents can highly benefit from learning their opponent’s preferences. Multiple algorithms have been developed with the two main categories being: heuristic techniques and machine learning techniques. Historically, heuristic techniques have dominated the field, but with the recent development in the field of machine learning, this is no longer true. The main goal of the paper is to compare these two techniques quantitatively using the Pearson correlation of bids. The models that were chosen as the heuristic and machine learning baseline are the Smith and the Perceptron models, respectively. Our results show that the two baselines have similar performance. This leads us to conclude that machine learning algorithms have caught up with their heuristic counterparts. Furthermore, we have also found a statistically significant correlation between the Perceptron model’s accuracy and the seen bid space.CSE3000 Research ProjectComputer Science and Engineerin
Contact Angle Measurement on Medical Implant Titanium Based Biomaterials
No full textAbstractThe aim of present research was to study the effect of some surface modification processes on wettability of Ti6Al4V surfaces for medical implants quantified by using the measurement of contact angle. The surface modification procedures of several disc samples were performed by sand blasting, acid etching, passivation, and their combinations. Sand blasting was done with 250...300μm SiO2 large grits. The acid etching process was performed in a dual bath of H2SO4 1n and HCl 1n (1:1) at different elevated temperatures (60°C, 80°C, and 100°C) using different process durations (1h, 3h, 6h, 12h, and 24h). Passivation was done in 30% HNO3 at room temperature. On modified surfaces we evaluated topography, by measuring roughness, and analyzing scanning electron micrographs. Contact angle was measured using static method and direct measurement of the tangent angle at the three-phase contact point on a sessile drop profile. We found that the influence of sand blasting prior to acid etching at low temperature (60°C) on contact angle is beneficial when using long acid etching times (12h and 24h). Increasing the process time for acid etching leads to a decrease in contact angle which is a desired result. Increasing the temperature of acid etching bath leads to an increase in contact angle, thus decreasing the wettability. The passivation treatment leads to an increase of contact angle on sand blasted surfaces, lowering the hydrophilic properties of surfaces, and does not influence significantly the contact angle on surface without sand blasting treatment. The best preparation procedure, in terms of wettability measured by contact angle, was found to be sand blasting, followed by acid etching in above mentioned dual acid bath at 60°C for 24hours. In this case we measured a contact angle of 46° showing good hydrophilic properties
NATIONAL STATISTICAL SEMINAR „OCTAV ONICESCU”
No full textOrganized by the National Institute of Statistics, together with Romanian Statistical Society, the seminar was meant to present and launch the paper „Romania 2012 – economic situation in perpetual crisis”. INS president, Ph.D. prof. Vergil Voineagu pointed out the valuable activity carried out by the author especially since 1998, by the elaboration of an important number of papers regarding economic situation of Romania in various stages
Influence of Surface Preparation on Morphology of Self-organized Nanotubular Oxide Layers Developed on Ti6Al4V Alloy
No full textPolynomial Approximation on Unbounded Subsets, Markov Moment Problem and Other Applications
No full textThis paper starts by recalling the author’s results on polynomial approximation over a Cartesian product A of closed unbounded intervals and its applications to solving Markov moment problems. Under natural assumptions, the existence and uniqueness of the solution are deduced. The characterization of the existence of the solution is formulated by two inequalities, one of which involves only quadratic forms. This is the first aim of this work. Characterizing the positivity of a bounded linear operator only by means of quadratic forms is the second aim. From the latter point of view, one solves completely the difficulty arising from the fact that there exist nonnegative polynomials on ℝn, n≥2, which are not sums of squares
Two important traditional prices' indices for the measurement of inflation and cost-of-living in Romania, during the last century
No full textThis paper details the two original constructions of price indices made by the author in the last ten years. These constructions are a proposal of centennial price index and an over eighty years old Romanian cost-of-living index.statistical index, interpret index, cost-of-living index (CLI), consumer price index (PCI), harmonized consumer price index (HPCI), Schumpeterian index, centennial index.
The Impact of Living Arrangements on the Prevalence of Falls after Total Joint Arthroplasty: A Comparison between Institutionalized and General Geriatric Population
No full textDue to population aging, there is an increasing need for orthopedic surgery, especially total knee arthroplasty (TKA) and total hip arthroplasty (THA). In geriatric patients, postoperative falls are common events which can compromise the success of these expensive procedures. The aim of our study was to assess the influence of living arrangements on the prevalence of postoperative falls following joint replacement. We included 441 patients after TKA or THA, living in nursing homes, alone or with family. The prevalence of falls in the first 2 years (15.2%) was significantly influenced by living arrangements: patients with TKA or THA living alone had three times higher odds of falling compared to those living with family, and institutionalized patients with THA had four times higher odds of falling compared to those living with family. Of 67 patients who fell, 6 (8.9%) needed reintervention. For TKA patients, the fall rates were not significantly different between institutions and family, indicating the interest of nursing homes in offering proper care. However, for the THA group, the results were poorer, emphasizing the need for improvement in postoperative rehabilitation. Further multi-centric studies are required for generalizing the impact of living arrangements on fall prevalence after joint replacement
Will Total Knee Replacement Ever Provide Normal Knee Function?
No full textKnee osteoarthritis or gonarthrosis is considered the most common joint disease, affecting more than 70% of subjects aged over 65 years. Its occurrence is increasing with age and is more problematic with the current rise in the incidence of obesity. In severe and advanced cases, total knee arthroplasty is recommended as a gold standard therapy for pain relief, restoration of normal knee function, and quality of life improvement. There are numerous controversies whether total knee arthroplasty is able to reach and provide end-point outcomes and restore previous function of the knee joint. Studies suggest that the surgeons’ experience, type of prosthesis used, associated pathology, underlying pathologies, risk factors, continuous passive movement, and patient expectations about the surgery may influence the outcomes to a great extent. “Normal knee function” is a statement that is hardly defined in the current literature, as authors usually refer to subjective results when analyzing outcomes. Objective results may be more straightforward, but they do not always symbolize the actual state that the patient is reporting or the actual quality of life. Our objective was to analyze and present summaries of the current literature regarding normal knee function restoration after total knee replacement surgery. Our literature review results confirm the hypothesis that subjective and objective results are difficult to interpret and unravel. Complex future trials may bring supplementary and clearer conclusions regarding knee function and kinematics, clinical improvement, patient satisfaction, and quality of life
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