Bregman Divergence Bounds and the Universality of the Logarithmic Loss

A loss function measures the discrepancy between the true values and their estimated fits, for a given instance of data. In classification problems, a loss function is said to be proper if the minimizer of the expected loss is the true underlying probability. In this work we show that for binary classification, the divergence associated with smooth, proper and convex loss functions is bounded from above by the Kullback-Leibler (KL) divergence, up to a normalization constant. It implies that by minimizing the log-loss (associated with the KL divergence), we minimize an upper bound to any choice of loss from this set. This property suggests that the log-loss is universal in the sense that it provides performance guarantees to a broad class of accuracy measures. Importantly, our notion of universality is not restricted to a specific problem. This allows us to apply our results to many applications, including predictive modeling, data clustering and sample complexity analysis. Further, we show that the KL divergence bounds from above any separable Bregman divergence that is convex in its second argument (up to a normalization constant). This result introduces a new set of divergence inequalities, similar to Pinsker inequality, and extends well-known $f$-divergence inequality results.Comment: arXiv admin note: substantial text overlap with arXiv:1805.0380

Designed solution for the foundation pit protection of the underground garage in Vlajkovićeva street

Within the design of the underground garage in Vlajkovićeva Street, various variant solutions for the foundation pit protection and neighboring buildings were considered. It is necessary to meet the condition that the stability of the sides of the excavation is ensured during the works and later in the operation of the facility, as well as to enable quality execution of works. Based on the performed analyzes, it can be concluded that the production of "single" diaphragm lamellas with the installation of prefabricated elements and the construction of a protective wall between them in two phases in specific conditions is the most favorable solution

Experimental testing of axial load capacity and stability of circular CFT columns

The paper presents the experimental testing of the axial capacity and stability of short, moderately slender and slender circular CFT columns. For the purpose of sample testing a special set of hydraulic presses was constructed. In order to achieve centric loading of the load, a device calotte was used. With the help of the dosing and gauges placed at the top of the column, force and vertical displacement were measured continuously. The test was carried out on two short columns 0.5 m and 1.0 m long, and four moderately slender and slender columns with a length of 4.0 m with different boundary support conditions. In the short CFT columns the confinement effect was taken into account as well and loss of bearing capacity occurred due to the steel profile yield strength. In moderately slender and slender columns, the loss of stability occurs before the loss of the load capacity of the column. The obtained results of the experimental tests were then compared with the valid regulations: EC4, ACI, AS and AISC. It can be concluded that EC4 gives the most approximate results to the experiment

Numerički postupak za određivanje stanja deformacija i napona u AB presecima

U radu je dat predlog jednog numeričkog postupka za određivanje stanja deformacija i napona u armiranobetonskim presecima. Postupak se zasniva na MKE sa korišćenjem “fiber“ elemenata. Za predložene veze napona i deformacija u betonu i armaturi prema EC2, razrađen je numerički postupak pomoću koga se u presecima složenog oblika, koji su armirani proizvoljnom armaturom, veoma brzo sa velikom tačnošću određuje stanje dilatacija i napona u betonu i armaturi, za zadato opterećenje. Izlazni rezultati se prikazuju u tabelarnom i grafičkom obliku i kao takvi su veoma pogodni za koriščenje u inženjerskoj praksi

Analiza nosivosti privremenih stubova kod ‘’Top Down’’ metode gradnje

One of the methods of construction which are increasingly used in urban conditions is a "Top Down" method. This method of construction is suitable when constructing buildings with a larger number of underground floors. Construction of the building is done from top to bottom where the ceilings of a structure are used for shoring of the structure for pit protection. One of the important elements in this method are internal ceiling supports. In the design engineers tend to minimise the costs and dimensions of these supports. This leads to the problem of their stability and capacity. This paper presents the analysis of bearing capacity of steel pipe filled with concrete which is on the bottom end elastically wedged in a pile and on the upper end in a constructed cealing of the building.Jedna od metoda gradnje koja se sve više primenjuje u gradskim uslovima jeste "Top Down" metoda. Ovakav način gradnje je pogodan kada se izvode objekti sa većim brojem podzemnih etaža. Konstrukcija objekta izvodi se odozgo na dole pri čemu se tavanicama objekta vrši razupiranje zaštitne konstrukcije temeljne jame. Jedan od bitnih elemenata kod ove metode jesu unutrašnji oslonci tavanica. Pri projektovanju teži se da koštanje, odnosno dimenzije ovih oslonaca budu minimalne. To dovodi do problema njihove stabilnosti i nosivosti. U radu se prikazuje analiza nosivosti stuba od čeličnih cevi ispunjenih betonom koji su sa donje strane elastično uklješteni u šip, a sa gornje strane u izvedenu konstrukciju objekta

Landslide stabilization in cut zone number 6 from km 28 + 478,00 to km 28 + 643,00

In the cut zone number 6 on E-80 Niš-Dimitrovgrad highway from km 28 + 478,00 to km 28 + 643,00 slope stability was affected causing mass movement. Additional inclinometers measured the mass wasting thickness between 14 m and 25 m. The height of the cut determined the slope protective backfilled gallery to be the best solution. The paper presents the detailed geostatic calculation of landslide stabilization using computer programs Plaxis 2D and RocScience Slide. Further, it shows the static calculation of the protective gallery in the computer program Radimpex Tower 3D. Results confirmed that the proposed structure was rigid enough to provide the necessary protection for the road structure

Collective Effects in Nuclear Collisions: Experimental Overview

These conferences proceedings summarize the experimental findings of collective effects in nuclear collisions, as presented at the Quark Matter 2018 conference.Comment: Final version of proceedings for an invited overview talk in XXVIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2018), Venezia, Ital

Static calculation of stabilization of the landslide in cut 4 from km 878+650 to km 879+050

The paper presents retaining structure to stabilize the landslide in the middle section from 878+775 to km 878+825, and slope protection on both left and right sides in order to provide vertical cutting and excavation to the level of highway platform. Retaining structure was designed as micro-pile wall with three different types of walls depending on the pile position. Micro-pile is made from steel pipe dia. Ø139.6 mm and 8.8mm thick wall, which is filled with cement mortar of minimum strength 30 MPa. In a constructive view, the designed retaining structure is a plate that is resting on the continual tie beams, which are supported in discrete points by geotechnical anchors. Calculation of stability and bearing capacity of protective structure was carried out in several phases. Phases are modeled according to the technology of execution of works. The calculation was performed in FEM program called Plaxis 2D. This calculation is based on the finite element method, using an incremental, iterative process. Based on the performed analysis, calculation of stability and bearing capacity, it can beconcluded that designed support structure satisfies all the necessary conditions of stability and bearing capacity

Experimental Investigation and Numerical Analysis of the Axial Load Capacity of Circular Concrete-Filled Tubular Columns

This paper focuses on the experimental investigation of the axial load capacity of CFT (concrete-filled steel tube) columns under actual construction conditions during building reconstruction. A total of four samples were loaded up to failure. The varied parameters were the column length and absence/presence of the concrete infill within the steel tube. Further, the analysis is extended to developing a numerical model in the finite element-based software ABAQUS version 6.9. This numerical model includes material and geometrical nonlinearities and was validated with the experimental results. The contribution of the concrete core to the column capacity and the concrete core confinement effect are discussed. Finally, the column capacity was calculated according to several design codes: the Eurocode 4 with and without considering the confinement effect, American specifications, Australian standards, the American Institute of Steel Construction, and the Architectural Institute of Japan. The Eurocode 4 considering the confinement effect provides the closest results to those obtained in the tests

Bearing capacity calculation for middle slender and slender CFT circular columns

In middle slender and slender CFT columns the loss of capacity is based on the problem of stability. In this case, we must take into account the effects of the second order. A nonlinear model was created in computer program Abaqus. In the model a nonlinear constitutive models for concrete core and steel hollow section, as well as the connection of these two elements was used. The critical buckling force of CFT column was obtained by modified Riks method. The influence of boundary conditions and the diameter and wall thickness of steel profiles on the critical buckling force was analyzed