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Nonlinear filtering for Markov systems with delayed observations
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Nonlinear Filtering for Markov Systems with Delayed Observations
No full textThis paper deals with nonlinear filtering problems with delays, i.e., we consider a system (X, Y), which can be represented by means of a system (X, (Y) over cap), in the sense that Y-t = (Y) over cap (a)(t), where a(t) is a delayed time transformation. We start with X being a Markov process, and then study Markovian systems, not necessarily diffusive, with correlated noises. The interest is focused on the existence of explicit representations of the corresponding filters as functionals depending on the observed trajectory. Various assumptions on the function a(t) are considered
Otitoma elegans Morassi & Nappo & Bonfitto 2017, sp. nov.
No full text<i>Otitoma elegans</i> sp. nov. <p>urn:lsid:zoobank.org:act: 0BBFAA0A-95F9-4068-A7D0-9A7A68E2F03E</p> <p>Fig. 5 I–O</p> Etymology <p> The specific epithet refers to the Latin ‘ <i>elegans</i> ’, meaning ‘characterized by refined grace’, alluding to the aesthetically pleasant appearance of the shell.</p> Type material <p> <b>Holotype</b></p> <p> FIJI ISLANDS: BORDAU 1, Stn DW 1465, 18°09 <b>′</b> S, 178°39 <b>′</b> W, 290–300 m (MHNH IM-2000-32606).</p> Description <p>Shell fusiform (b/l 0.38; a/l 0.55). Teleoconch of slightly less than 7 convex whorls, with periphery at middle of the 3 earliest whorls, posterior to mid-whorl on the later whorls. Whorls separated by a distinct suture bordered by a spiral cord. Sutural ramp moderately concave. Axial sculpture consisting of opisthocline ribs, subequal to broader than intercostal spaces, extending on spire whorls from suture to abapical side of sutural ramp, prominent on earlier whorls, but becoming remarkably weaker on last whorl. 21 axial ribs on penultimate whorl and 17 on last whorl. Spiral sculpture consists of widelyspaced, narrow, weakly prominent spiral cords, somewhat plicate where crossing axial ribs. Earliest three whorls with two cords between sutural ramp and abapical suture, increasing to three cords on fourth and antepenultimate whorls and four on penultimate and last whorls. Last whorl with 13 spiral cords on base and rostrum. Insterpaces between cords sculptured by numerous fine spiral threads (up to 14) (Fig. 5 K–L). Aperture rather narrow, lanceolate, constricted at entrance to siphonal canal. Siphonal canal moderately long, not notched terminally. Inner lip with moderately thin callus, parietal region with a pad formed by termination of outer lip. Outer lip edge sharp, preceded by a wide, low, rounded varix. Anal sinus moderately deep, apically rounded, asymmetrically U-shaped, not strongly constricted at opening. Stromboid notch moderately deep. Protoconch of 1½ smooth, domed whorls with few sparse microscopic granules when observed under SEM (Fig. 5N), diameter 0.86 mm. Color yellowish-white with brown-orange spiral cords.</p> Dimensions <p> Holotype: 12.6 <i>×</i> 4.8 mm, aperture height 7.0 mm.</p> Remarks <p> Although only a single specimen of <i>Otitoma elegans</i> sp. nov. is available, this species differs distinctly from its described congeners in having only a few, widely-spaced primary spiral cords with well developed secondary spiral sculpture, and a peculiar color pattern (yellowish-white with brown-orange spiral cords). <i>O. elegans</i> sp. nov. further differs from its congeners of similar size in possessing a paucispiral and domed protoconch instead of multispiral and conical.</p>Published as part of <i>Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, pp. 1-30 in European Journal of Taxonomy 304</i> on page 20, DOI: 10.5852/ejt.2017.304, <a href="http://zenodo.org/record/3825824">http://zenodo.org/record/3825824</a>
Otitoma hadra Morassi & Nappo & Bonfitto 2017, sp. nov.
No full textOtitoma hadra sp. nov. urn:lsid:zoobank.org:act: D699962E-3975-4973-A6AB-047323F41C8B Fig. 4 P–U Etymology The specific epithet refers to the Greek ‘ hadros ’ (thick), alluding to the small but very thick shell. Type material Holotype NEW CALEDONIA: BATHUS 4, Stn DW 882, N of New Caledonia, 22°02 ′ S, 165°56 ′ E, 250–350 m (MNHN IM-2000-32603). Paratype NEW CALEDONIA: same data as holotype (MNHN IM- 2000-32604). Description Shell somewhat biconic (b/l 0.41–0.48; a/l 0.56–0.57). Teleoconch of 3–3¼ weakly and evenly convex whorls, with a slight shoulder at mid-whorl height. Suture shallow, bordered by a weakly prominent sub-sutural fold followed by a shallowly concave sutural ramp. Axial sculpture of opisthocline ribs, subequal to or narrower than intercostal spaces, abruptly ending at level of abapical side of sutural ramp (Fig. 4S). 14–16 axial ribs on penultimate and 18–19 ribs on last whorl. First teleoconch whorl with 3 spiral cords between the sutural ramp, sutures of following whorl increasing to 4–5 on penultimate and last whorl. Spiral cords closely-spaced, not plicate where crossing axial ribs. Sutural ramp with 1 spiral cord increasing to 2 cords on later two whorls. Last whorl with 19–22 main spiral cords and 1 occasional secondary cord in interspaces on base and rostrum. Interspaces between cords lacking secondary sculpture. Aperture rather narrow, ovate, constricted at entrance to siphonal canal. Siphonal canal short, relatively wide. Inner lip covered with a thick callus. Outer lip edge sharp, preceded by a strong, wide varix. Stromboid notch weak. Anal sinus relatively broad and moderately deep, a C-shaped notch, its entrance weakly constricted. Protoconch domed, of up to 1½ smooth whorls, diameter 1.04– 1.09 mm. Protoconch white, teleoconch yellowish-white flecked with orange-yellow on sutural ramp and along some axial ribs on last whorl. Dimensions Holotype: 5.1 × 2.1 mm, aperture height 2.85 mm. Paratype: 4.7 × 2.25 mm, aperture height 2.7 mm. Remarks Otitoma hadra sp. nov. is readily distinguished from its described congeners by its rather small, thick shell (about 5 mm in maximum length), with a relatively large protoconch and well developed sculpture (both spiral and axial).Published as part of Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, pp. 1-30 in European Journal of Taxonomy 304 on pages 16-17, DOI: 10.5852/ejt.2017.304, http://zenodo.org/record/382582
Approximation of nonlinear filters for Markov systems with delayed observations
No full textThe aim of this paper is to give some approximation results for a class of nonlinear filtering problems with delay in the observation. First, we point out some general results on the approximation problem for the filter in nonlinear filtering. In particular, we give a general procedure for obtaining some upper bounds for the different approximations we consider. This procedure is then applied in the case of nonlinear filtering problems with delay , which can be represented by means of a Markov system , in the sense that . Finally, these upper bounds are computed explicitly in the particular case of Markov jump process with counting observations
Nonlinear filtering for stochastic systems with fixed delay: Approximation by a modified Milstein scheme
No full textIn this paper we study approximation schemes for a nonlinear filtering problem of a partially observed diffusive system when the state process X is the solution of a stochastic delay diffusion equation with a constant time lag tau and the observation process is a noisy function of the state. The approximating state is the linear interpolation of a modified Milstein scheme, which is asymptotically optimal with respect to the mean square l(2)-error within the class of all pathwise approximations based on equidistant observations of the driving Brownian motion. Upper bounds for the error of the filter approximations are computed. Some other discretization schemes for the state process are also considered. (C) 2011 Elsevier Ltd. All rights reserved
Nonlinear filtering for Markov diffusion systems with delayed observations
No full textIn this paper, we consider a nonlinear filtering problem when the state process is a diffusion X-t and the observations start at a fixed time tau and from that time on depend on the delayed process Xt-tau
Convergence in nonlinear filtering for stochastic delay systems
No full textWe study an approximation scheme for a nonlinear filtering problem when the state process X is the solution of a stochastic delay diffusion equation and the observation process is a noisy function of X(s) for s is an element of [t - tau, t], where tau is a constant. The approximating state is the piecewise linear Euler-Maruyama scheme, and the observation process is a noisy function of the approximating state. The rate of convergence of this scheme is computed
Otitoma crassivaricosa Morassi & Nappo & Bonfitto 2017, sp. nov.
No full text<i>Otitoma crassivaricosa</i> sp. nov. <p>urn:lsid:zoobank.org:act: 54B1C89F-BA68-4388-B719-73B4B71BB55F</p> <p>Fig. 6 A–H</p> Etymology <p> The specific epithet is a combination of the Latin words ‘ <i>crassus</i> ’ (thick) and ‘ <i>varicosus</i> ’ (bearing varices), alluding to the well developed axial sculpture.</p> Type material <p> <b>Holotype</b></p> <p> MARQUESAS ARCHIPELAGO: MUSORSTOM 9, Stn DW 1218, Hiva Oa Island, 9°44.5 <b>′</b> S, 138°50.9 <b>′</b> W, 125–135 m (MNHN IM-2000-32607).</p> <p> <b>Paratypes</b></p> <p>MARQUESAS ARCHIPELAGO: Paratype 1, same data as holotype (MZB 60216).</p> <p> FIJI ISLANDS: Paratype 2, MUSORSTOM 10, Stn DW1365, 18°12.7 <b>′</b> S, 178°32.4 <b>′</b> E, 295–302 m (MNHN IM- 2000-32608).</p> Description <p>Shell fusiform-cylindrical (b/l 0.37–0.40; a/l 0.50–0.52). Teleoconch of up to 5¾ weakly convex whorls. Suture distinct, bordered by a moderately prominent sutural fold, followed by a moderately concave sutural ramp. Axial sculpture consisting of opisthocline axial ribs, rather straight and rounded, equal to or wider than intervals, developing mainly in peripheral region, gradually disappearing on abapical portion of sutural ramp. 13–14 axial ribs on penultimate whorl, 11–12 on last whorl. Spiral sculpture consisting of widely-spaced cords, not forming distinct nodules at their intersection with axial ribs. First two teleoconch whorls with 3 spiral cords between sutural ramp and whorl base, increasing to 5–6 on later two whorls. Last whorl with 12 spiral cords on base and rostrum. Interspaces between spiral cords covered by microscopic spiral threads, 4–7 between spiral cords on later two teleoconch whorls (Fig. 6 C–D). Aperture narrowly elliptical, constricted at entrance to siphonal canal. Siphonal canal short, slightly expanded at its end, and somewhat obliquely truncate. Outer lip edge sharp, preceded by a wide, prominent rounded varix. Stromboid notch strong. Anal sinus rather deep, apically rounded, its entrance strongly constricted by parietal pad. Protoconch narrowly conical, of 3¼ whorls, smooth except for presence of sparse microgranules, diameter 0.82–0.84 mm (Fig. 6 E–H). Color yellowish-white with yellowish-orange spiral cords.</p> Dimensions <p> Holotype: 9.85 <i>×</i> 3.7 mm, aperture height 5.1 mm. Paratype 1: 9.3 <i>×</i> 3.7 mm, aperture height 4.65 mm; paratype 2: 11.2 <i>×</i> 4.1 mm, aperture height 5.3 mm.</p> Remarks <p> This species differs from its congeners by the combination of a narrowly conical protoconch, strong axial sculpture and well-developed secondary spiral sculpture. It may superficially resemble some specimens of <i>O. cyclophora</i>, from which it differs mainly in having broader axial ribs, a less constricted entrance to the anal sinus, and different protoconch features (narrowly conical, of 3¼ whorls rather than bluntly papillose, of about 1¾ whorls; see Kilburn 2004: 268).</p>Published as part of <i>Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, pp. 1-30 in European Journal of Taxonomy 304</i> on pages 22-24, DOI: 10.5852/ejt.2017.304, <a href="http://zenodo.org/record/3825824">http://zenodo.org/record/3825824</a>
I nuovi documentaristi tedeschi : stile documentario e forme di sopravvivenza della fotografia della Neue Sachlichkeit nella Germania Ovest (1959-1980)
No full textThis study aims to investigate the critical success and influence that the photography of the New Objectivity (August Sander, Albert Renger-Patzsch and Karl Blossfeldt) had on German photographic scene of the 1960s and 1970s. Particular importance is given to the reconstruction of the artistic and photographic context of West Germany between 1959 and 1980 (photo galleries, militant criticism, the debate on documentary photography in magazines, international art fairs and exhibitions), as well as to the analysis of the work of the New German Documentary Photographers. These photographers, recognized as the major representatives of the so-called Autorenfotografie (authors photography), try to record the contemporary landscape, city and man in a way that is straightforward, sober and objective at the same time without giving up their own authorial identity, marked by a highly recognizable style.Il presente studio si propone di indagare la fortuna critica e l’influenza della fotografia della Neue Sachlichkeit (August Sander, Albert Renger-Patzsch e Karl Blossfeldt) nel panorama fotografico tedesco degli anni Sessanta e Settanta del Novecento. Particolare rilevanza è conferita alla ricostruzione del contesto artistico-fotografico della Germania Ovest tra il 1959 e il 1980 (le gallerie fotografiche, la critica militante, il dibattito sul documentario accolto nelle riviste di settore, le mostre, le fiere e le manifestazioni d’arte internazionali), nonché all’analisi dell’opera dei Nuovi Documentaristi tedeschi. Questi fotografi, riconosciuti come rappresentanti di punta di quella che è stata ribattezzata Autorenfotografie (fotografia degli autori), cercano di registrare il paesaggio, la città e l’uomo contemporanei in modo diretto, sobrio e oggettivo senza al contempo rinunciare a una propria identità autoriale, segnata da una forte riconoscibilità stilistica
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