352 research outputs found
Computational results for an automatically tuned CMA-ES with increasing population size on the CEC'05 benchmark set
Abstract In this article, we apply an automatic algorithm configuration tool to improve the performance of the CMA-ES algorithm with increasing population size (iCMA-ES), the best performing algorithm on the CEC'05 benchmark set for continuous function optimization. In particular, we consider a separation between tuning and test sets and, thus, tune iCMA-ES on a different set of functions than the ones of the CEC'05 benchmark set. Our experimental results show that the tuned iCMA-ES improves significantly over the default version of iCMA-ES. Furthermore, we provide some further analyses on the impact of the modified parameter settings on iCMA-ES performance and a comparison with recent results of algorithms that use CMA-ES as a subordinate local search
Mesoporous Co 3 O 4 as an electrocatalyst for water oxidation
ABSTRACT Mesoporous Co 3 O 4 has been prepared using porous silica as a hard template via a nanocasting route and its electrocatalytic properties were investigated as an oxygen evolution catalyst for the electrolysis of water. The ordered mesostructured Co 3 O 4 shows dramatically increased catalytic activity compared to that of bulk Co 3 O 4 . Enhanced catalytic activity was achieved with high porosity and surface area, and the water oxidation overpotential (η) of the ordered mesoporous Co 3 O 4 decreases significantly as the surface area increases. The mesoporous Co 3 O 4 also shows excellent structural stability in alkaline media. After 100 min under 0.8 V (versus Ag/AgCl) applied bias, the sample maintains the ordered mesoporous structure with little deactivation of the catalytic properties
Fine Selmer Groups and Isogeny Invariance
We investigate fine Selmer groups for elliptic curves and for Galois
representations over a number field. More specifically, we discuss Conjecture
A, which states that the fine Selmer group of an elliptic curve over the
cyclotomic extension is a finitely generated -module. The
relationship between this conjecture and Iwasawa's classical conjecture
is clarified. We also present some partial results towards the question whether
Conjecture A is invariant under isogenies.Comment: 20 page
BFF: A Tool for Eliciting Tie Strength and User Communities in Social Networking Services
López Fogués, R.; Such Aparicio, JM.; Espinosa Minguet, AR.; GarcÃa-Fornes, A. (2014 Abstract The use of social networking services (SNSs) such as Facebook has explosively grown in the last few years. Users see these SNSs as useful tools to find friends and interact with them. Moreover, SNSs allow their users to share photos, videos, and express their thoughts and feelings. However, users are usually concerned about their privacy when using SNSs. This is because the public image of a subject can be affected by photos or comments posted on a social network. In this way, recent studies demonstrate that users are demanding better mechanisms to protect their privacy. An appropriate approximation to solve this could be a privacy assistant software agent that automatically suggests a privacy policy for any item to be shared on a SNS. The first step for developing such an agent is to be able to elicit meaningful information that can lead to accurate privacy policy predictions. In particular, the information needed is user communities and the strength of users' relationships, which, as suggested by recent empirical evidence, are the most important factors that drive disclosure in SNSs. Given the number of friends that users can have and the number of communities they may be involved on, it is infeasible that users are able to provide this information without the whole eliciting process becoming confusing and time consuming. In this work, we present a tool called Best Friend Forever (BFF) that automatically classifies the friends of a user in communities and assigns a value to the strength of the relationship ties to each one. We also present an experimental evaluation involving 38 subjects that showed that BFF can significantly alleviate the burden of eliciting communities and relationship strength
Robust reduction of graphene fluoride using an electrostatically biased scanning probe
ABSTRACT We report a novel and easily accessible method to chemically reduce graphene fluoride (GF) sheets with nanoscopic precision using high electrostatic fields generated between an atomic force microscope (AFM) tip and the GF substrate. Reduction of fluorine by the electric field produces graphene nanoribbons (GNR) with a width of 105-1,800 nm with sheet resistivity drastically decreased from >1 TΩ·sq. -1 (GF) down to 46 kΩ·sq. -1 (GNR). Fluorine reduction also changes the topography, friction, and work function of the GF. Kelvin probe force microscopy measurements indicate that the work function of GF is 180-280 meV greater than that of graphene. The reduction process was optimized by varying the AFM probe velocity between 1.2 μm·s -1 and 12 μm·s -1 and the bias voltage applied to the sample between -8 and -12 V. The electrostatic field required to remove fluorine from carbon is ~1.6 V·nm -1 . Reduction of the fluorine may be due to the softening of the C-F bond in this intense field or to the accumulation and hydrolysis of adventitious water into a meniscus
The EANM clinical and technical guidelines for lymphoscintigraphy and sentinel node localization in gynaecological cancers
Abstract The accurate harvesting of a sentinel node in gynaecological cancer (i.e. vaginal, vulvar, cervical, endometrial or ovarian cancer) includes a sequence of procedures with components from different medical specialities (nuclear medicine, radiology, surgical oncology and pathology). These guidelines are divided into sectione entitled: Purpose, Background information and definitions, Clinical indications and contraindications for SLN detection, Procedures (in the nuclear medicine department, in the surgical suite, and for radiation dosimetry), and Issues requiring further clarification. The guidelines were prepared for nuclear medicine physicians. The intention is to offer assistance in optimizing the diagnostic information that can currently be obtained from sentinel lymph node procedures. If specific recommendations given cannot be based on evidence from original scientific studies, referral is made to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, and the performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for high-quality evaluation of possible metastatic spread to the lymphatic system in gynaecological cancer. The final result has been discussed by a group of distinguished experts from the EANM Oncology Committee and the European Society of Gynaecological Oncology (ESGO). The document has been endorsed by the SNMMI Board
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