Attempto - From Specifications in Controlled Natural Language towards Executable Specifications

Deriving formal specifications from informal requirements is difficult since one has to take into account the disparate conceptual worlds of the application domain and of software development. To bridge the conceptual gap we propose controlled natural language as a textual view on formal specifications in logic. The specification language Attempto Controlled English (ACE) is a subset of natural language that can be accurately and efficiently processed by a computer, but is expressive enough to allow natural usage. The Attempto system translates specifications in ACE into discourse representation structures and into Prolog. The resulting knowledge base can be queried in ACE for verification, and it can be executed for simulation, prototyping and validation of the specification.Comment: 15 pages, compressed, uuencoded Postscript, to be presented at EMISA Workshop 'Naturlichsprachlicher Entwurf von Informationssystemen - Grundlagen, Methoden, Werkzeuge, Anwendungen', May 28-30, 1996, Ev. Akademie Tutzin

Specifying Logic Programs in Controlled Natural Language

Writing specifications for computer programs is not easy since one has to take into account the disparate conceptual worlds of the application domain and of software development. To bridge this conceptual gap we propose controlled natural language as a declarative and application-specific specification language. Controlled natural language is a subset of natural language that can be accurately and efficiently processed by a computer, but is expressive enough to allow natural usage by non-specialists. Specifications in controlled natural language are automatically translated into Prolog clauses, hence become formal and executable. The translation uses a definite clause grammar (DCG) enhanced by feature structures. Inter-text references of the specification, e.g. anaphora, are resolved with the help of discourse representation theory (DRT). The generated Prolog clauses are added to a knowledge base. We have implemented a prototypical specification system that successfully processes the specification of a simple automated teller machine.Comment: 16 pages, compressed, uuencoded Postscript, published in Proceedings CLNLP 95, COMPULOGNET/ELSNET/EAGLES Workshop on Computational Logic for Natural Language Processing, Edinburgh, April 3-5, 199

Attempto Controlled English (ACE)

Attempto Controlled English (ACE) allows domain specialists to interactively formulate requirements specifications in domain concepts. ACE can be accurately and efficiently processed by a computer, but is expressive enough to allow natural usage. The Attempto system translates specification texts in ACE into discourse representation structures and optionally into Prolog. Translated specification texts are incrementally added to a knowledge base. This knowledge base can be queried in ACE for verification, and it can be executed for simulation, prototyping and validation of the specification.Comment: 13 pages, compressed, uuencoded Postscript, to be presented at CLAW 96, The First International Workshop on Controlled Language Applications, Katholieke Universiteit Leuven, 26-27 March 199

Fish and bivalves at Bolsa Chica Marsh re-establishment project; Progress report III

The objectives of our fish and bivalve study are: 1. Determine changes in the number of species of fish and bivalves before Phase I and during Phase 1 at Bolsa Chica Marsh. 2. Determine if California Department of Fish and Game's predicted benefits in Phase I were achieved by increases in fish species. 3. Determine influences of water management practices upon fish and bivalve composition. Thirteen species of fish and five species of bivalves were collected from Inner Bolsa Bay and South Bolsa Slough. Deepbody anchovy, Anchoa compressa; jacksmelt, Atherinopsis californiensis; longjaw mudsucker, Gillichthys mirabilis; specklefin midshipman, Porichthys myriaster; round stingray, Urolophus halleri; banded chione, Chione californiensis; bentnose clam, Macoma nasuta; and common littleneck clam, Protothaca staminea have not been reported previously from Inner Bolsa Bay. Nine species of fish and four species of bivalves were collected from outer Bolsa Bay. Yellowfin goby, Acanthogobius flavimanus; longjaw mudsucker; tilapia, Tilapia mossambica; and bay pipefish, Syngnathus leptorhynchus have not been reported previously from Outer Bolsa Bay. (11pp.

Development and application of a particle-particle particle-mesh Ewald method for dispersion interactions

For inhomogeneous systems with interfaces, the inclusion of long-range dispersion interactions is necessary to achieve consistency between molecular simulation calculations and experimental results. For accurate and efficient incorporation of these contributions, we have implemented a particle-particle particle-mesh (PPPM) Ewald solver for dispersion ($r^{-6}$) interactions into the LAMMPS molecular dynamics package. We demonstrate that the solver's $\mathcal{O}(N\log N)$ scaling behavior allows its application to large-scale simulations. We carefully determine a set of parameters for the solver that provides accurate results and efficient computation. We perform a series of simulations with Lennard-Jones particles, SPC/E water, and hexane to show that with our choice of parameters the dependence of physical results on the chosen cutoff radius is removed. Physical results and computation time of these simulations are compared to results obtained using either a plain cutoff or a traditional Ewald sum for dispersion.Comment: 31 pages, 9 figure

The Preparation of Liposomes Derived From Mixed Micelles of Lecithin Added by Sodium Cholate, Followed by Dialysing Using Hemoflow High Flux F60S

Liposomes are used for drug carriers meaning that drugs are incorporated in the membrane or the vesicle of the liposomes. In this study, liposomes were prepared from mixed micelles, consisting of phosphatidylcholine, without or with cholesterol and sodium cholate was added in several ratios namely 0.44; 0.55; 0.63; 0.70; 0.90 and 1.10. After the preparation, the sodium cholate has been removed by a dialysis membrane, using the Hemoflow High Flux, which is generally used for haemodialysis. The Hemoflow High Flux is a tool in an effort to obtain a simple, quick, effective method for removing sodium cholate in the process of preparing liposomes. The effectiveness of this tool was proved by the particle size of the liposome which was measured by the Malvern Particle Sizer. The particle size of the liposome consisting of phosphatidylcholine (PC) without cholesterol and with cholesterol was 63-68 nm at all ratios and approximately 125 nm at the ratio of 0.55; 0.63; 0.70, respectively. The particle size of the liposome tended to be smaller after dialyzing, although the concentration of lipids tended to increase. However, a large amount of buffer solution has to be used with this method

Self-propelled Worm-like Filaments: Spontaneous Spiral Formation, Structure, and Dynamics

Worm-like filaments that are propelled homogeneously along their tangent vector are studied by Brownian dynamics simulations. Systems in two dimensions are investigated, corresponding to filaments adsorbed to interfaces or surfaces. A large parameter space covering weak and strong propulsion, as well as flexible and stiff filaments is explored. For strongly propelled and flexible filaments, the free-swimming filaments spontaneously form stable spirals. The propulsion force has a strong impact on dynamic properties, such as the rotational and translational mean square displacement and the rate of conformational sampling. In particular, when the active self-propulsion dominates thermal diffusion, but is too weak for spiral formation, the rotational diffusion coefficient has an activity-induced contribution given by $v_c/\xi_P$, where $v_c$ is the contour velocity and $\xi_P$ the persistence length. In contrast, structural properties are hardly affected by the activity of the system, as long as no spirals form. The model mimics common features of biological systems, such as microtubules and actin filaments on motility assays or slender bacteria, and artificially designed microswimmers