Detecting an Intermittent Change of Unknown Duration

Oftentimes in practice, the observed process changes statistical properties at an unknown point in time and the duration of a change is substantially finite, in which case one says that the change is intermittent or transient. We provide an overview of existing approaches for intermittent change detection and advocate in favor of a particular setting driven by the intermittent nature of the change. We propose a novel optimization criterion that is more appropriate for many applied areas such as the detection of threats in physical-computer systems, near-Earth space informatics, epidemiology, pharmacokinetics, etc. We argue that controlling the local conditional probability of a false alarm, rather than the familiar average run length to a false alarm, and maximizing the local conditional probability of detection is a more reasonable approach versus a traditional quickest change detection approach that requires minimizing the expected delay to detection. We adopt the maximum likelihood (ML) approach with respect to the change duration and show that several commonly used detection rules (CUSUM, window-limited CUSUM, and FMA) are equivalent to the ML-based stopping times. We discuss how to choose design parameters for these rules and provide a comprehensive simulation study to corroborate intuitive expectations.Comment: 34 pages, 7 figures, 6 table

Effet de l’urée et du NPK 15-15-15 perlés et super granulés sur la productivité des variétés de riz IR841 et NERICA-L14 en zone de bas-fond au Sud-Bénin

Objectives: The study was carried out on the site of Koussin and Lélé in the southern Benin, exploring the efficiency of the supply of the pearl and super granule urea (46%) and NPK 15-15-15 for rice production in the inland valley. Specifically, the study aims to assess the effect of the different forms of urea and NPK 15- 15-15 on the growth and yield parameters of two inland rice varieties (IR841 and NERICA-L14) widely adopted in cultivated lowland of Benin. Methodology and results: The experimental design is a split-plot with two rice varieties, four forms of fertilizer (pearl urea + NPK; pearl urea + super granule NPK; super granule urea + pearl NPK and super granule urea + super granule NPK) in four replications. The growth and yield parameters were assessed. Super granule urea + super granule NPK and super granule urea + pearl NPK have significantly (P < 0.0001) induced higher plant height, numbers of tiller and rice grain per panicle compared with the other treatments whatever the rice variety. However, mean yields of paddy rice and straw were significantly higher (P < 0,0001) for super granule urea + super granule NPK (paddy rice yield : 5,52 ± 0,26 t/ha ; straw yield : 12,19 ± 0,54 t/ha) and super granule urea + pearl NPK (paddy rice yield: 4,82 ± 0,22 t/ha ; straw yield : 10,79 ± 0,61 t/ha). In general with these treatments, the highest yields were recorded with IR841 rice variety. Conclusion and application: The super granule fertilizers are recommended for improving rice production in the inland valley as they improve substantially the yields. In order to improve the efficiency of these fertilizers especially the sources of nitrogen, the study suggests to supply urea super granule + NPK super granule or urea super granule + pearl NPK to improve growth and yields parameter of IR841 rice variety.Keywords: inland valley; super granule fertilizer; soil fertility; irrigated rice production; Benin

Seismic noise parameters as indicators of reversible modifications in slope stability: a review

Continuous ambient seismic monitoring of potentially unstable sites is increasingly attracting the attention of researchers for precursor recognition and early warning purposes. Twelve cases of long-term continuous noise monitoring have been reported in the literature between 2012 and 2020. Only in a few cases rupture was achieved and irreversible drops in resonance frequency values or shear wave velocity extracted from noise recordings were documented. On the other hand, all monitored sites showed clear reversible fluctuations of the seismic parameters on a daily and seasonal scale due to changes in external weather conditions (air temperature and precipitation). A quantitative comparison of these reversible modifications is used to gain insight into the mechanisms driving the site seismic response. Six possible mechanisms were identified, including three temperature-driven mechanisms (temperature control on fracture opening/closing, superficial stress conditions and bulk rigidity), one precipitation-driven mechanism (water infiltration effect) and two mechanisms sensitive to both temperature and precipitation (ice formation and clay behavior). The reversible variations in seismic parameters under the meteorological constraints are synthesized and compared to the irreversible changes observed prior to failure in different geological conditions

SBS 0335-052W - an Extremely Low Metallicity Dwarf Galaxy

We present Multiple Mirror Telescope (MMT) and Keck II telescope spectrophotometry and 3.5m Calar Alto telescope R, I photometry of the western component of the extremely low-metallicity blue compact galaxy SBS 0335-052. The components, separated by 22 kpc, appear to be members of a unique, physically connected system. It is shown that SBS 0335-052W consists of at least three stellar clusters and has the same redshift as SBS 0335-052. The oxygen abundance in its two brightest knots is extremely low, 12+log(O/H)= 7.22+/-0.03 and 7.13+/-0.08, respectively. These values are lower than in SBS 0335-052 and are nearly the same as those in I Zw 18. The (R-I) color profiles are very blue in both galaxies due to the combined effects of ionized gas and a young stellar population emission. We argue that SBS 0335-052W is likely to be a nearby, young dwarf galaxy.Comment: 18 pages, 4 EPS figures, to appear in ApJ, 1 July 199

The VMC Survey - XIII : Type II Cepheids in the Large Magellanic Cloud

Date of Acceptance: 27/10/2014The VISTA (Visible and Infrared Survey Telescope for Astronomy) survey of the Magellanic Clouds System (VMC) is collecting deep Ks-band time-series photometry of the pulsating variable stars hosted in the system formed by the two Magellanic Clouds and the Bridge connecting them. In this paper, we have analysed a sample of 130 Large Magellanic Cloud (LMC) Type II Cepheids (T2CEPs) found in tiles with complete or near-complete VMC observations for which identification and optical magnitudes were obtained from the OGLE III (Optical Gravitational Lensing Experiment) survey. We present J and Ks light curves for all 130 pulsators, including 41 BL Her, 62 W Vir (12 pW Vir) and 27 RV Tau variables. We complement our near-infrared photometry with the V magnitudes from the OGLE III survey, allowing us to build a variety of period-luminosity (PL), period-luminosity-colour (PLC) and period-Wesenheit (PW) relationships, including any combination of the V, J, Ks filters and valid for BL Her and W Vir classes. These relationships were calibrated in terms of the LMC distance modulus, while an independent absolute calibration of the PL(Ks) and the PW(Ks, V) was derived on the basis of distances obtained from Hubble Space Telescope parallaxes and Baade-Wesselink technique. When applied to the LMC and to the Galactic globular clusters hosting T2CEPs, these relations seem to show that (1) the two Population II standard candles RR Lyrae and T2CEPs give results in excellent agreement with each other; (2) there is a discrepancy of ~0.1 mag between Population II standard candles and classical Cepheids when the distances are gauged in a similar way for all the quoted pulsators. However, given the uncertainties, this discrepancy is within the formal 1σ uncertainties.Peer reviewedFinal Accepted Versio

Asymptotic Reduction of a Lithium-ion Pouch Cell Model

A three-dimensional model of a single-layer lithium-ion pouch cell is presented which couples conventional porous electrode theory describing cell electrochemical behaviour with an energy balance describing cell thermal behaviour. Asymptotic analysis of the model is carried out by exploiting the small aspect ratio typical of pouch cell designs. The analysis reveals the scaling that results in a distinguished limit, and highlights the role played by the electrical conductivities of the current collectors. The resulting model comprises a collection of one-dimensional models for the through-cell electrochemical behaviour which are coupled via two-dimensional problems for the Ohmic and thermal behaviour in the planar current collectors. A further limit is identified which reduces the problem to a single volume-averaged through-cell model, greatly reducing the computational complexity. Numerical simulations are presented which illustrate and validate the asymptotic results.Comment: 27 pages, 6 figures, submitted to SIAM Journal on Applied Mathematics (08/05/2020

Massive expanding torus and fast outflow in planetary nebula NGC 6302

We present interferometric observations of $^{12}$CO and $^{13}$CO $J$=2$-$1 emission from the butterfly-shaped, young planetary nebula NGC 6302. The high angular resolution and high sensitivity achieved in our observations allow us to resolve the nebula into two distinct kinematic components: (1) a massive expanding torus seen almost edge-on and oriented in the North-South direction, roughly perpendicular to the optical nebula axis. The torus exhibits very complex and fragmentated structure; (2) high velocity molecular knots moving at high velocity, higher than 20 \kms, and located in the optical bipolar lobes. These knots show a linear position-velocity gradient (Hubble-like flow), which is characteristic of fast molecular outflow in young planetary nebulae. From the low but variable $^{12}$CO/$^{13}$CO $J$=2$-$1 line intensity ratio we conclude that the $^{12}$CO $J$=2$-$1 emission is optically thick over much of the nebula. Using the optically thinner line $^{13}$CO $J$=2$-$1 we estimate a total molecular gas mass of $\sim$ 0.1 M$_\odot$, comparable to the ionized gas mass; the total gas mass of the NGC 6302 nebula, including the massive ionized gas from photon dominated region, is found to be $\sim$ 0.5 M$_\odot$. From radiative transfer modelling we infer that the torus is seen at inclination angle of 75$^\circ$ with respect to the plane of the sky and expanding at velocity of 15 \kms. Comparison with recent observations of molecular gas in NGC 6302 is also discussed.Comment: 24 pages, 7 figures, accepted for publication in Astrophysical Journa

Combate À Corrupção Na Rússia Moderna: Problemas E Perspectivas

The authors analyze the problems and perspectives of fighting against corruption in modern Russia based on the materials of a sociological survey conducted in November-December 2017 by the Laboratory of Problems of Improving the Efficiency of State and Municipal Management in the South-Russian Institute of Management (the branch of the Russian Presidential Academy of National Economy and Public Administration) in 15 regions of the Russian Federation within preparation for the Round Table with an international participation "Problems of fighting against corruption in the state and municipal service and ways to solve them in modern Russia" (16-17 February, 2018, Rostov-on-Don).In the paper there are analyzed the assessments of experts on the content of corruption in Russia, its level; there are also identified threats to security formed by corruption manifestations. The authors clarify the main reasons for bribery of state and municipal employees, determine the areas affected by corruption to the greatest extent; examine the role of the Federal Law of the Russian Federation "On Fighting against corruption" in the implementation of anti-corruption measures, assess the effectiveness of the ban on employees to receive gifts in connection with their official position; examine the opinion of experts on the advisability of adding greater punitive measures or mitigation of punishment for bribery.At the end of the paper, directions for improving anti-corruption activities are formulated. The authors of the paper concluded that the increase in the effectiveness of anti-corruption activities depends on the depth of corruption nature research and the forms of corruption manifestation in contemporary Russian society. In the current situation, along with the repressive method of suppression of corruption manifestations, the strategic direction of combating corruption should be to identify and eliminate the causes and factors that form corruption risks.Los autores analizan los problemas y perspectivas de la lucha contra la corrupción en la Rusia moderna sobre la base de los materiales de una encuesta sociológica realizada en noviembre-diciembre de 2017 por el Laboratorio de Problemas de Mejora de la Eficiencia de la Administración Estatal y Municipal en el Instituto de Administración del Sur de Rusia (la rama de la Academia Presidencial Rusa de Economía Nacional y Administración Pública) en 15 regiones de la Federación Rusa en preparación para la Mesa Redonda con una participación internacional "Problemas de lucha contra la corrupción en el servicio estatal y municipal y formas de resolverlos en Rusia moderna "(16-17 febrero, 2018, Rostov-on-Don).En el documento se analizan las evaluaciones de expertos sobre el contenido de la corrupción en Rusia, su nivel; también se identifican amenazas a la seguridad formadas por manifestaciones de corrupción. Los autores aclaran las principales razones del soborno de los empleados estatales y municipales, determinan las áreas afectadas por la corrupción en la mayor medida; examinar el papel de la Ley Federal de la Federación de Rusia "sobre la lucha contra la corrupción" en la aplicación de medidas contra la corrupción, evaluar la eficacia de la prohibición de que los empleados reciban obsequios en relación con su posición oficial; examine la opinión de los expertos sobre la conveniencia de agregar medidas punitivas más importantes o la mitigación del castigo por soborno.Al final del documento, se formulan instrucciones para mejorar las actividades anticorrupción. Los autores del documento concluyeron que el aumento en la efectividad de las actividades anticorrupción depende de la profundidad de la investigación de la naturaleza de la corrupción y las formas de manifestación de corrupción en la sociedad rusa contemporánea. En la situación actual, junto con el método represivo de represión de las manifestaciones de corrupción, la dirección estratégica para combatir la corrupción debe ser identificar y eliminar las causas y los factores que forman los riesgos de corrupción.Os autores analisam os problemas e perspectivas da luta contra a corrupção na Rússia moderna, com base em materiais de uma pesquisa sociológica realizada em novembro-dezembro 2017 pela Melhoria da Eficiência Problemas Laboratório da Administração Estatal e Municipal no Instituto de Administração no sul da Rússia (o ramo da Academia Presidencial Russa de Economia Nacional e da Administração Pública) em 15 regiões da Federação Russa em preparação para a Mesa Redonda com a participação internacional "Problemas de anti-corrupção estado e de serviços municipais e as formas de resolvê-los na Rússia moderna "(16-17 fevereiro de 2018, Rostov-on-Don).As avaliações de especialistas documento sobre o conteúdo da corrupção na Rússia, analisa seu nível; Ameaças de segurança formadas por manifestações de corrupção também são identificadas. Os autores esclarecem as principais razões de suborno de funcionários estaduais e municipais, determinar as áreas afetadas pela corrupção em toda a extensão; examinar o papel da Lei Federal da Federação Russa "na luta contra a corrupção" na implementação de medidas anti-corrupção, avaliar a eficácia da proibição de que os funcionários recebam presentes em conexão com a sua posição oficial; examinar a opinião de especialistas sobre a possibilidade de adicionar mais importantes medidas punitivas ou mitigar a punição para o suborno.No final do documento, as instruções são formulados para aumentar as actividades anti-corrupção. Os autores do documento concluiu que o aumento da eficácia das actividades anti-corrupção depende da profundidade de investigação da natureza da corrupção e formas de manifestação da corrupção na sociedade russa contemporânea. Na situação atual, juntamente com o método repressivo da repressão de manifestações de corrupção, direcionamento estratégico para combater a corrupção deve ser identificar e eliminar as causas e os fatores são os riscos de corrupção

Optical conductivity of metal nanofilms and nanowires: The rectangular-box model

The conductivity tensor is introduced for the low-dimensional electron systems. Within the particle-in-a-box model and the diagonal response approximation, components of the conductivity tensor for a quasi-homogeneous ultrathin metal film and wire are calculated under the assumption $d\cong \lambda_{\rm F}$ (where $d$ is the characteristic small dimension of the system, $\lambda_{\rm F}$ is the Fermi wavelength for bulk metal). We find the transmittance of ultrathin films and compare these results with available experimental data. The analytical estimations for the size dependence of the Fermi level are presented, and the oscillations of the Fermi energy in ultrathin films and wires are computed. Our results demonstrate the strong size and frequency dependences of the real and imaginary parts of the conductivity components in the infrared range. A sharp distinction of the results for Au and Pb is observed and explained by the difference in the relaxation time of these metals.Comment: 13 pages, 8 figure

A Suite of Reduced-Order Models of a Single-Layer Lithium-ion Pouch Cell

For many practical applications, fully coupled three-dimensional models describing the behaviour of lithium-ion pouch cells are too computationally expensive. However, owing to the small aspect ratio of typical pouch cell designs, such models are well approximated by splitting the problem into a model for through-cell behaviour and a model for the transverse behaviour. In this paper, we combine different simplifications to through-cell and transverse models to develop a hierarchy of reduced-order pouch cell models. We give a critical numerical comparison of each of these models in both isothermal and thermal settings, and also study their performance on realistic drive cycle data. Finally, we make recommendations regarding model selection, taking into account the available computational resource and the quantities of interest in a particular study