Застосування мінімаксного підходу для сегмениації судин сітківки

The paper presents the results of work neural network for segmentation of the fundus vessels using the Tensorflow machine learning library. Training and testing takes place on the public DRIVE data set. The results of work model, namely the recognized blood vessels are presented.When considering binary cross-entropy as an indicator of efficiency, which is demonstrated in the article, it was determined that the U-Net model with 8x8 tiles is a solution to the problem of minimax ML. In the first step, the value of the loss function is compared for all considered models. In the second step, it is determined that the value of binary cross-entropy for the U-Net model with 8x8 tiles will be the minimum among the maximum characteristics.When considering training time as an indicator of efficiency, as shown in the relevant table, the U-Net model with 25x25 tiles is a solution to the minimax ML problem. In the first step, we first compare the values of the training time of all the models under consideration. In the second step, it is determined that the time value for the U-Net model with 25x25 tiles will be the minimum among the maximum values.У роботі представлені результати роботи нейронної мережі для сегментації судин очного дна з використанням бібліотеки машинного навчання Tensorflow. Навчання і тестування відбувається на загальнодоступному наборі даних DRIVE. Результати роботи моделі, а саме розпізнані кровоносні судини є представлені.При розгляді бінарної крос-ентропії як показника ефективності, що є продемонстровано у статті, визначено, що модель U-Net з плитками 8x8 є рішенням проблеми minimax ML. На першому кроці, відбувається порівняння значення функції втрат для всіх розглянутих моделей. На другому кроці визначено, що значення бінарної крос-ентропії для моделі U-Net з плитками 8x8 буде мінімальним серед максимальних характеристик. При розгляді часу навчання як показником ефективності, що продемонстровано у відповідній таблиці, модель U-Net з плитками 25x25 є рішенням проблеми minimax ML. На першому кроці, спочатку відбувається порівняння значення часу тренування всіх моделей, що розглядаються. На другому кроці визначено, що значення часу для моделі U-Net з плитками 25x25 буде мінімальним серед максимальних показників.Ключові слова: сегментація судин сітківки, нейронна мережа, машинне навчання, мінімаксний підхід, бібліотека машинного навчання.

Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U) in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR) and two Pebble-Bed Accelerator Driven Systems (ADSs) was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.Received: 09 February 2015; Revised: 12 May 2015; Accepted: 20 May 201

Assessment of and Response to Data Needs of Clinical and Translational Science Researchers and Beyond

Objective and Setting: As universities and libraries grapple with data management and “big data,” the need for data management solutions across disciplines is particularly relevant in clinical and translational science (CTS) research, which is designed to traverse disciplinary and institutional boundaries. At the University of Florida Health Science Center Library, a team of librarians undertook an assessment of the research data management needs of CTS researchers, including an online assessment and follow-up one-on-one interviews. Design and Methods: The 20-question online assessment was distributed to all investigators affiliated with UF’s Clinical and Translational Science Institute (CTSI) and 59 investigators responded. Follow-up in-depth interviews were conducted with nine faculty and staff members. Results: Results indicate that UF’s CTS researchers have diverse data management needs that are often specific to their discipline or current research project and span the data lifecycle. A common theme in responses was the need for consistent data management training, particularly for graduate students; this led to localized training within the Health Science Center and CTSI, as well as campus-wide training. Another campus-wide outcome was the creation of an action-oriented Data Management/Curation Task Force, led by the libraries and with participation from Research Computing and the Office of Research. Conclusions: Initiating conversations with affected stakeholders and campus leadership about best practices in data management and implications for institutional policy shows the library’s proactive leadership and furthers our goal to provide concrete guidance to our users in this area

Laser-assisted guiding of electric discharges around objects

Electric breakdown in air occurs for electric fields exceeding 34 kV/cm and results in a large current surge that propagates along unpredictable trajectories. Guiding such currents across specific paths in a controllable manner could allow protection against lightning strikes and high-voltage capacitor discharges. Such capabilities can be used for delivering charge to specific targets, for electronic jamming, or for applications associated with electric welding and machining. We show that judiciously shaped laser radiation can be effectively used to manipulate the discharge along a complex path and to produce electric discharges that unfold along a predefined trajectory. Remarkably, such laser-induced arcing can even circumvent an object that completely occludes the line of sight

Demonstration of the BNL Continuous Dual Trap Analyzer to Detect Perfluorocarbon Tracers for the Tag, Track and Location Program

The Tag, Track and Location System (TTL) Program is investigating methods of tracking an asset using perfluorocarbon tracers (PFT). The success of any TTL method requires sound detection/location instrumentation. Tracer Detection Technologies Corp (TDT), through a contract with the Office of Naval Research (ONR), is investigating different detection systems. The detections systems generally fall into two categories; proximity detectors and standoff detectors. Proximity detectors, as the name implies, need to be in close proximity (e.g., meter to 10's of meters) to the PFT source. Standoff detection searches for the PFT from a greater distance away from the source (e.g., 100's of meters to kilometers). Gas Chromatographs (GC) are generally considered a proximity detection systems, but in the case of PFTs should be considered for both proximity and standoff detection with the caveat that in standoff use the GC needs to be somewhere in the PFT plume, i.e., generally downwind of the source. With a properly sized PFT source, the right GC can afford fairly large standoff (distance from the source) distances; 100's of meters to kilometers downwind. Brookhaven National Laboratory (BNL) has such a GC system and offered to demonstrate the CDTA for TTL as a no cost addition to the TDTTTL project, of which BNL was a participant. BNL is a leading authority on the sampling, collection, release and detection of PFTs. In addition, the BNL team has extensive background in atmospheric dispersion, the application of PFTs to such studies and the development of applications utilizing PFTs such as building infiltration measurements, control room integrity determination, leak location and environmental investigations. This experience and expertise is essential in developing any PFT application were dispersion, dilution and overcoming environmental conditions and interferences are integral to success. BNL has developed sophisticated gas chromatography methods and instruments that allow detection of up to seven PFTs at part per quadrillion levels (1015) with sample times as short as 60 seconds. The Continuous Dual-Trap Analyzer (CDTA) was developed for leak hunting applications and can continuously sample the air for PFTs without interruption. Sample time can be as short as 60 seconds. The CDTA has been extensively used in the commercial sector to detect PFTs that have been introduced to leaking buried dielectric fluid-filled cables or leaking subsurface gas lines. The PFTs travel through the cable or pipe until they reach the leak site. PFTs then escape into the surrounding soil and permeate/diffuse to the surface where they can be detected with the CDTA. Typically a cable is tagged with ppm levels of PFTs resulting in ppt to ppq concentrations in the air at the leak site. The CDTA is proven to be rugged, reliable and has a proven track record of successful leak location. The application of the CDTA to PFT detection for TTL is identical to application for leak detection. The CDTA operator has a general idea, with a few miles of roadway, where the leak is located, but no specific knowledge of the location (it can be any where along the road). The CDTA is mounted in a Chevy Astro Van and is dispatched to the field. In the field the van is driven at nominally 15 mph along the road. The CDTA continuously samples the air outside the van (via a 1/4-inch plastic sample tube stuck out a side window) until a positive detection occurs. The van then covers the road section where the detection occurred at a slightly slower pace to pin-point the area where the leak is and to direct soil probe samples. The soil probe samples take soil gas samples every 10 yards or so and the samples are analyzed on the CDTA. The leak can be located to within a few feet in 95% of the cases. To date the CDTA has been successful in every leak hunt performed by BNL. One interesting case was a leak hunt that resulted in repeated negative detections. The confidence in the CDTA forced the utility to recheck its 'plumbing' which lead to the discovery that a valve was turned that shouldn't have been so that gas was being diverted rather than leaking (the pressure drop was due to this diversion of the gas to another line). For TTL application, a tagged item or person is known to be in a general area and can be located by detecting the PFT emanating from the tagging source. The CDTA can be deployed in the area and by sampling in a grid fashion (starting on the downwind side of the area of interest) can easily find even very small sources. The CDTA is a perfect match for this application and the leak hunt use basically a simulation of Track and Locate. No other PFT detection technology has the detection sensitivity, proven track record and ruggedness of the CDTA. For these reasons, BNL offered to demonstrate the CDTA for TTL as a no cost addition to the TTL lidar demonstration project. This report details the demonstration scenario and results

Robust three-dimensional high-order solitons and breathers in driven dissipative systems: a Kerr cavity realization

We present a general approach to excite robust dissipative three-dimensional and high-order solitons and breathers in passively driven nonlinear cavities. Our findings are illustrated in the paradigmatic example provided by an optical Kerr cavity with diffraction and anomalous dispersion, with the addition of an attractive three-dimensional parabolic potential. The potential breaks the translational symmetry along all directions, and impacts the system in a qualitatively unexpected manner: three-dimensional solitons, or light-bullets, are the only existing and stable states for a given set of parameters. This property is extremely rare, if not unknown, in passive nonlinear physical systems. As a result, the excitation of the cavity with any input field leads to the deterministic formation of a target soliton or breather, with a spatiotemporal profile that unambiguously corresponds to the given cavity and pumping conditions. In addition, the tuning of the potential width along the temporal direction results in the existence of a plethora of stable asymmetric solitons. Our results may provide a solid route towards the observation of dissipative light bullets and three-dimensional breathers

Treatability study on the use of by-product sulfur in Kazakhstan for the stabilization of hazardous and radioactive wastes

The Republic of Kazakhstan generates significant quantities of excess elemental sulfur from the production and refining of petroleum reserves. In addition, the country also produces hazardous, and radioactive wastes which require treatment/stabilization. In an effort to find secondary uses for the elemental sulfur, and simultaneously produce a material which could be used to encapsulate, and reduce the dispersion of harmful contaminants into the environment, BNL evaluated the use of the sulfur polymer cement (SPC) produced from by-product sulfur in Kazakhstan. This thermoplastic binder material forms a durable waste form with low leaching properties and is compatible with a wide range of waste types. Several hundred kilograms of Kazakhstan sulfur were shipped to the US and converted to SPC (by reaction with 5 wt% organic modifiers) for use in this study. A phosphogypsum sand waste generated in Kazakhstan during the purification of phosphate fertilizer was selected for treatment. Waste loadings of 40 wt% were easily achieved. Waste form performance testing included compressive strength, water immersion, and Accelerated Leach Testing