The unified coordination language UnCL.

In this paper we show how to use a (subset) of UML as an Unified Coordination Language (UnCL) that is based on a separation of concerns between coordination and computation. As such UnCL provides a general language for the coordination of, in particular, object-oriented applications. The basic idea of UnCL is to use UML as a formalism to specify the `glue code' in terms of state-machines which are added to the classes of the underlying applications. These state-machines describe the coordination of the objects of the underlying applications in terms of sending and receiving events. We introduce a formal semantics of UnCL and discuss its implementation using a new tool for the transformation of XML data which is based on a new Rule Markup Language (RML). Finally, we discuss the incorporation of a more high-level coordination mechanism called MoCha, an exogenous coordination framework for (distributed) communication and collaboration using mobile channels as its mediu

An Introduction to Nuclear Supersymmetry: a Unification Scheme for Nuclei

The main ideas behind nuclear supersymmetry are presented, starting from the basic concepts of symmetry and the methods of group theory in physics. We propose new, more stringent experimental tests that probe the supersymmetry classification in nuclei and point out that specific correlations should exist for particle transfer intensities among supersymmetric partners. We also discuss possible ways to generalize these ideas to cases where no dynamical symmetries are present. The combination of these theoretical and experimental studies may play a unifying role in nuclear phenomena.Comment: 40 pages, 11 figures, lecture notes `VIII Hispalensis International Summer School: Exotic Nuclear Physics', Oromana, Sevilla, Spain, June 9-21, 200

A channel-based coordination model for components

In this paper we present a coordination model for component-based software systems based on the notion of mobile channels, and describe its implementation in the Java language. Channels allow anonymous, and point-to-point communication among components, while mobility allows dynamic reconfiguration of channel connections in a system. This model supports dynamic distributed systems where components can be mobile. It provides an efficient way of interaction among components. Furthermore, our model provides a clear separation between the computational part and the coordination part of a system, allowing the development and description of the coordination structure of a system to be done in a transparent way. Our description of the Java implementation of this coordination model demonstrates that it is self-contained enough for developing component-based systems. However, if desired, our model can be used as a basis to extend other models that focus on other aspects of components that are less related to composition and coordination concerns

Spectrophotometric analysis of the Ryugu rock seen by MASCOT: Searching for a carbonaceous chondrite analog

We analyze images of a rock on Ryugu acquired in situ by MASCam, camera of the MASCOT lander, with the aim of identifying possible carbonaceous chondrite (CC) analogs. The rock's reflectance ($r_{\rm F} = 0.034 \pm 0.003$ at phase angle $4.5^\circ \pm 0.1^\circ$) is consistent with Ryugu's average reflectance, suggesting that the rock is typical for this asteroid. A spectrophotometric analysis of the rock's inclusions provides clues to CC group membership. Inclusions are generally brighter than the matrix. The dominant variation in their color is a change of the visible spectral slope, with many inclusions being either red or blue. Spectral variation in the red channel hints at the presence of the 0.7~$\mu$m absorption band linked to hydrated phyllosilicates. The inclusions are unusually large for a CC; we find that their size distribution may best match that of the Renazzo (CR2) and Leoville (CV3) meteorites. The Ryugu rock does not easily fit into any of the CC groups, consistent with the idea that typical Ryugu-type meteorites are too fragile to survive atmospheric entry

Thermal fracturing on comets: Applications to 67P/Churyumov-Gerasimenko

We simulate the stresses induced by temperature changes in a putative hard layer near the surface of comet 67P/Churyumov-Gerasimenko with a thermo-viscoelastic model. Such a layer could be formed by the recondensation or sintering of water ice (and dust grains), as suggested by laboratory experiments and computer simulations, and would explain the high compressive strength encountered by experiments on board the Philae lander. Changes in temperature from seasonal insolation variation penetrate into the comet’s surface to depths controlled by the thermal inertia, causing the material to expand and contract. Modelling this with a Maxwellian viscoelastic response on a spherical nucleus, we show that a hard, icy layer with similar properties to Martian permafrost will experience high stresses: up to tens of MPa, which exceed its material strength (a few MPa), down to depths of centimetres to a metre. The stress distribution with latitude is confirmed qualitatively when taking into account the comet’s complex shape but neglecting thermal inertia. Stress is found to be comparable to the material strength everywhere for sufficient thermal inertia (≳ 50 J m−2 K−1 s−1∕2) and ice content (≳ 45% at the equator). In this case, stresses penetrate to a typical depth of ~0.25 m, consistent with the detection of metre-scale thermal contraction crack polygons all over the comet. Thermal fracturing may be an important erosion process on cometary surfaces which breaks down material and weakens cliffs

Recursive calculation of matrix elements for the generalized seniority shell model

A recursive calculational scheme is developed for matrix elements in the generalized seniority scheme for the nuclear shell model. Recurrence relations are derived which permit straightforward and efficient computation of matrix elements of one-body and two-body operators and basis state overlaps.Comment: 19 pages, 1 figure; published in Nucl. Phys.

Analytic descriptions for transitional nuclei near the critical point

Exact solutions of the Bohr Hamiltonian with a five-dimensional square well potential, in isolation or coupled to a fermion by the five-dimensional spin-orbit interaction, are considered as examples of a new class of dynamical symmetry or Bose-Fermi dynamical symmetry. The solutions provide baselines for experimental studies of even-even [E(5)] and odd-mass [E(5|4)] nuclei near the critical point of the spherical to deformed gamma-unstable phase transition.Comment: LaTeX (elsart), 53 pages; typographical correction to (3.15