A Dichotomy Theorem for Homomorphism Polynomials

In the present paper we show a dichotomy theorem for the complexity of polynomial evaluation. We associate to each graph H a polynomial that encodes all graphs of a fixed size homomorphic to H. We show that this family is computable by arithmetic circuits in constant depth if H has a loop or no edge and that it is hard otherwise (i.e., complete for VNP, the arithmetic class related to #P). We also demonstrate the hardness over the rational field of cut eliminator, a polynomial defined by B\"urgisser which is known to be neither VP nor VNP-complete in the field of two elements, if VP is not equal to VNP (VP is the class of polynomials computable by arithmetic circuit of polynomial size)

On the reduction of the CSP dichotomy conjecture to digraphs

It is well known that the constraint satisfaction problem over general relational structures can be reduced in polynomial time to digraphs. We present a simple variant of such a reduction and use it to show that the algebraic dichotomy conjecture is equivalent to its restriction to digraphs and that the polynomial reduction can be made in logspace. We also show that our reduction preserves the bounded width property, i.e., solvability by local consistency methods. We discuss further algorithmic properties that are preserved and related open problems.Comment: 34 pages. Article is to appear in CP2013. This version includes two appendices with proofs of claims omitted from the main articl

ДВУХСТОРОННЕЕ ЭТАПНОЕ ЭНДОПРОТЕЗИРОВАНИЕ ГОЛЕНОСТОПНЫХ СУСТАВОВ У ПАЦИЕНТА С ВЫРАЖЕННЫМ ДЕФЕКТОМ ТАРАННОЙ КОСТИ (СЛУЧАЙ ИЗ ПРАКТИКИ)

Ankle arthroplasty is known to become more successful procedure versus ankle fusion in patients with ankle osteoarthritis. This article represents a clinical case of performing three-staged bilateral ankle arthroplasty by means of HINTEGRA and Mobility implants in a patient with severe defect of the talus. The patient was followed up for 2 years for right ankle and 4 years - for left ankle. The correct treatment strategy gave the patient a new lease of life. He resumed sports activities, being pain-free in both the ankle joints.Эндопротезирование голеностопного сустава становится все более востребованным видом оперативного лечения пациентов с остеоартрозом голеностопного сустава. Описан опыт двухстороннего этапного эндопротезирования голеностопного сустава протезами HINTEGRA (New Deal) и Mobility (DePuy) при выраженном дефекте таранной кости. Лечение пациента было выполнено в три этапа. Срок послеоперационного наблюдения составил 2 года для правого голеностопного сустава и 4 года для левого. Правильный выбор алгоритма лечения позволил снять болевой синдром, улучшить качество жизни пациента и восстановить его физическую активность

RGB color camera for dynamical measurements of high temperature distribution on a surface of the heated solid

In this report we describe a fast 3-color method of the measurement of temperature distributions on a surface of a heated solid using a RGB color camera with a high frame rate (100 images per second). Statistical error the RGB method is not high, and do not exceed around 5.5 % which is surprising taking in to account the number of the measurements at each pixel. Comparison of the results of the temperature measurements on a tungsten plate heated by infra-red laser radiation and conducted with this technique and those obtained with the acousto-optical tunable filter technique demonstrate that error of the temperature measured by 3-color method is only two times as high as that of the tandem acousto-optic filter technique method.This work was performed using the Unique Scientific Instrument 'Laser heating at diamond anvil cell'[http://ckp-rf.ru/usu/507563/]

Tractable Combinations of Global Constraints

We study the complexity of constraint satisfaction problems involving global constraints, i.e., special-purpose constraints provided by a solver and represented implicitly by a parametrised algorithm. Such constraints are widely used; indeed, they are one of the key reasons for the success of constraint programming in solving real-world problems. Previous work has focused on the development of efficient propagators for individual constraints. In this paper, we identify a new tractable class of constraint problems involving global constraints of unbounded arity. To do so, we combine structural restrictions with the observation that some important types of global constraint do not distinguish between large classes of equivalent solutions.Comment: To appear in proceedings of CP'13, LNCS 8124. arXiv admin note: text overlap with arXiv:1307.179

An electron miniaccelerator on the basis of Tesla transformer for nondestructive testing of charged particle beams

An electron miniaccelerator on the basis of Tesla-transformer for nondestructive testing of charged particle beams with operating voltage 120…200 kV, half-wave duration 4 mks and diagnostic beam current within few mA is described. The primary circuit is switched by IGBT. The gun control and filament circuit power supply (impregnated cathode with 1.2 mm diameter) are realized through high frequency isolated transformer. The accelerating tube is made of sectional welded metal ceramics insulator (ceramics 22HS with diameter 95/85 mm).The accelerator test results are presented.Описан миниускоритель электронов на основе трансформатора Тесла с рабочей амплитудой напряжения 120…200 кВ при длительности полуволны 4 мкс и током диагностичеcкого пучка в пределах нескольких мА. В качестве ключа первичного контура используется IGBT. Питание накала и цепей управления пушки (импрегнированный катод диаметром 1.2 мм) ускорителя осуществляется с помощью высокочастотного разделительного трансформатора броневого типа. Металлокерамический узел выполнен на базе керамики 22ХС диаметром 95/85 мм, соединяемой с электродами термокомпрессионной сваркой. Приведены результаты испытаний миниускорителя.Описано мініприскорювач електронів на основі трансформатора Тесла з робочою амплітудою напруги 120...200 кВ при тривалості напівхвилі 4 мкс і струмом діагностичного пучка в межах декількох мА. Як ключ первинного контуру використається ІGBT. Живлення розжарення й ланцюгів керування пушки (імпрегнований катод діаметром 1.2 мм) прискорювача здійснюється за допомогою високочастотного розділового трансформатора броньового типу. Металокерамічний вузол виконаний на базі кераміки 22ХС діаметром 95/85 мм, що з'єднує з електродами термокомпресіонним зварюванням. Наведено результати випробувань мініприскорювача

The STAR MAPS-based PiXeL detector

The PiXeL detector (PXL) for the Heavy Flavor Tracker (HFT) of the STAR experiment at RHIC is the first application of the state-of-the-art thin Monolithic Active Pixel Sensors (MAPS) technology in a collider environment. Custom built pixel sensors, their readout electronics and the detector mechanical structure are described in detail. Selected detector design aspects and production steps are presented. The detector operations during the three years of data taking (2014-2016) and the overall performance exceeding the design specifications are discussed in the conclusive sections of this paper

On Backdoors to Tractable Constraint Languages

International audienceIn the context of CSPs, a strong backdoor is a subset of variables such that every complete assignment yields a residual instance guaranteed to have a specified property. If the property allows efficient solving, then a small strong backdoor provides a reasonable decomposition of the original instance into easy instances. An important challenge is the design of algorithms that can find quickly a small strong backdoor if one exists. We present a systematic study of the parameterized complexity of backdoor detection when the target property is a restricted type of constraint language defined by means of a family of polymor-phisms. In particular, we show that under the weak assumption that the polymorphisms are idempotent, the problem is unlikely to be FPT when the parameter is either r (the constraint arity) or k (the size of the backdoor) unless P = NP or FPT = W[2]. When the parameter is k + r, however, we are able to identify large classes of languages for which the problem of finding a small backdoor is FPT

Multi-spectral image processing for the measurement of a spatial temperature distribution on the surface of a laser-heated microscopic object

In this paper, we demonstrate that combining a laser heating (LH) system with a tandem acousto-optical tunable filter (TAOTF) allows us to measure the temperature distribution (TD) across a laser-heated microscopic specimen. Spectral image processing is based on one-dimensional (1D) non-linear least squares fitting of the Planck radiation function. It is applied for determining the temperature T at each point (x, y) of the specimen surface. It is shown that spectral image processing using the 1D non-linear least squares fitting allows measurement of the TD of the laser-heated microscopic specimen with higher precision and stability than those of the conventional linear least-squares fitting of the Wien approximation of Planck’s law.The Russian Science Foundation (project #17-12-01535) financially supported the work