A tiny new species of Platypelis from the Marojejy National Park in northeastern Madagascar (Amphibia: Microhylidae)

We describe a tiny new frog species of the genus Platypelis (Anura: Microhylidae: Cophylinae) from Marojejy National Park, northeastern Madagascar. Platypelis ravus sp. nov. differs from all other known Platypelis and Cophyla species by its small size (17-19 mm snout-vent length) and a combination of other morphological and bioacoustic characters. The new species seems to be most closely related to P. milloti with which it shares the principal colour pattern, but exhibits a yellow rather than red posterior venter. Uncorrected pairwise sequence divergence in a 16S rRNA gene fragment to all other known species of the genus (except P. cowanii for which no genetic data is available) is greater than 6%. We suggest the inclusion of the new species in the IUCN threat category “Data Deficient”

Learning an Approximate Model Predictive Controller with Guarantees

A supervised learning framework is proposed to approximate a model predictive controller (MPC) with reduced computational complexity and guarantees on stability and constraint satisfaction. The framework can be used for a wide class of nonlinear systems. Any standard supervised learning technique (e.g. neural networks) can be employed to approximate the MPC from samples. In order to obtain closed-loop guarantees for the learned MPC, a robust MPC design is combined with statistical learning bounds. The MPC design ensures robustness to inaccurate inputs within given bounds, and Hoeffding's Inequality is used to validate that the learned MPC satisfies these bounds with high confidence. The result is a closed-loop statistical guarantee on stability and constraint satisfaction for the learned MPC. The proposed learning-based MPC framework is illustrated on a nonlinear benchmark problem, for which we learn a neural network controller with guarantees.Comment: 6 pages, 3 figures, to appear in IEEE Control Systems Letter

A new golden frog species of the genus Diasporus (Amphibia, Eleutherodactylidae) from the Cordillera Central, western Panama

We describe the frog species Diasporus citrinobapheussp. n. from the Cordillera Central of western Panama. The new species differs from all other species in its genus in coloration, disk cover and disk pad shape, skin texture, advertisement call, and size. It is most similar to Diasporus tigrillo, from which it differs in dorsal skin texture, relative tibia length, number of vomerine teeth, ventral coloration, dorsal markings, and relative tympanum size, and to Diasporus gularis, from which it can be distinguished by the lack of membranes between the toes, adult size, posterior thigh coloration, and position of the choanae. We provide data on morpho- logy, vocalization, and distribution of the new species, as well as brief information on its natural history.Describimos la especie de rana Diasporus citrinobapheus sp. n. de la Cordillera Central, occidente de Panamá. La nueva especie se distingue de otras especies del género por su coloración, su forma de la cubierta y la almohadilla de los discos, textura de la piel, canto de anúncio, y tamaño corporal. Se asemeja mas a D. tigrillo, del cual se distingue por la textura de la piel dorsal, longitud relativa de la tibia, número de dientes vomerianos, coloración ventral, patrón dorsal, y tamaño relativo del tímpano, y a D. gularis, del cual se diferencia por la ausencia de membranas entre los dedos de pie, tamaño corporal, coloración de la parte trasera del muslo, y posición de las coanas. Presentamos datos de la morfología, vocalización, y distribución de la nueva especie, así como notas concisas de su historia natural

Beetles on Scots pine : biodiversity and strata

Gewöhnliche Ausschnitte unserer Kulturlandschaft sind oft schlechter untersucht als unter Schutz stehende Landschaftsbestandteile. So war z.B. die Artenausstattung mancher Naturwälder eher bekannt als die Artenausstattung der umliegenden Nutzwälder. Durch die Initiativen und Forschungsprojekte u.a. von Ammer & al. (1995) wurde dann deutlich, dass auch Nutzwälder einen wertvollen Beitrag zur Artenvielfalt leisten können. Bei der Erforschung der Nutzwälder sind jedoch Kiefernforste nach wie vor vernachlässigt worden. Nur Arbeiten von Möller (2000) und Möller & Jakobitz (2003) in Brandenburg stellten hier wichtige Schritte dar, neuerdings ergänzt durch z.B. Reike & al. (2005). Im Folgenden werden neu ausgewertete Daten aus einem vom BMBF geförderten Forschungsprojekt vorgestellt, in dem sehr umfassende Grunderhebungen der in genutzten Kiefernforsten Brandenburgs vorkommenden Arthropoden durchgeführt wurden (Schulz & al. 2004, Majunke & al. 2005). Die folgenden Auswertungen konzentrieren sich auf die Artendiversität der an Kiefern (Pinus sylvestris L.) erfassten Käfer in Kiefernreinbeständen und auf die stratenspezifische Verteilung.Coleoptera were studied in three different pure stands of Scots pine (Pinus sylvestris L.) in Brandenburg (Germany) in the years 2000 to 2001. In order to catch beetles in different strata 36 standard traps were installed from the ground up to the canopy in each forest. 40836 specimen were determined to species level and 695 species were determined altogether. More than 430 beetle species were caught in each pine forest. These were more species than expected, but less than in other (mixed) forests of Germany. Only app. 54 % of all species were typical for forests (374 species altogether, 250 - 260 in each forest). A lot of species typical for open habitats benefit from the open and warm conditions in pine forests. 200 to 400 beetle species were collected in each stratum of the tree (e.g. 254 in the canopy). Flight interception traps in app. 2 m height yielded the best results collecting the largest amount of individuals (app. one third of all specimen) and the largest number of species (441). For future investigations in pine forests this method is therefore recommended if trapping has to be limited

Stability and performance in MPC using a finite-tail cost

In this paper, we provide a stability and performance analysis of model predictive control (MPC) schemes based on finite-tail costs. We study the MPC formulation originally proposed by Magni et al. (2001) wherein the standard terminal penalty is replaced by a finite-horizon cost of some stabilizing control law. In order to analyse the closed loop, we leverage the more recent technical machinery developed for MPC without terminal ingredients. For a specified set of initial conditions, we obtain sufficient conditions for stability and a performance bound in dependence of the prediction horizon and the extended horizon used for the terminal penalty. The main practical benefit of the considered finite-tail cost MPC formulation is the simpler offline design in combination with typically significantly less restrictive bounds on the prediction horizon to ensure stability. We demonstrate the benefits of the considered MPC formulation using the classical example of a four tank system

SLACID - Sparse Linear Algebra in a Column-Oriented In-Memory Database System

Scientific computations and analytical business applications are often based on linear algebra operations on large, sparse matrices. With the hardware shift of the primary storage from disc into memory it is now feasible to execute linear algebra queries directly in the database engine. This paper presents and compares different approaches of storing sparse matrices in an in-memory column-oriented database system. We show that a system layout derived from the compressed sparse row representation integrates well with a columnar database design and that the resulting architecture is moreover amenable to a wide range of non-numerical use cases when dictionary encoding is used. Dynamic matrix manipulation operations, like online insertion or deletion of elements, are not covered by most linear algebra frameworks. Therefore, we present a hybrid architecture that consists of a read-optimized main and a write-optimized delta structure and evaluate the performance for dynamic sparse matrix workloads by applying workflows of nuclear science and network graphs

Topology-aware optimization of big sparse matrices and matrix multiplications on main-memory systems

Since data sizes of analytical applications are continuously growing, many data scientists are switching from customized micro-solutions to scalable alternatives, such as statistical and scientific databases. However, many algorithms in data mining and science are expressed in terms of linear algebra, which is barely supported by major database vendors and big data solutions. On the other side, conventional linear algebra algorithms and legacy matrix representations are often not suitable for very large matrices. We propose a strategy for large matrix processing on modern multicore systems that is based on a novel, adaptive tile matrix representation (AT MATRIX). Our solution utilizes multiple techniques inspired from database technology, such as multidimensional data partitioning, cardinality estimation, indexing, dynamic rewrites, and many more in order to optimize the execution time. Based thereon we present a matrix multiplication operator ATMULT, which outperforms alternative approaches. The aim of our solution is to overcome the burden for data scientists of selecting appropriate algorithms and matrix storage representations. We evaluated AT MATRIX together with ATMULT on several real-world and synthetic random matrices