Transitioning from structural to nominal code with efficient gradual typing

Gradual typing is a principled means for mixing typed and untyped code. But typed and untyped code often exhibit different programming patterns. There is already substantial research investigating gradually giving types to code exhibiting typical untyped patterns, and some research investigating gradually removing types from code exhibiting typical typed patterns. This paper investigates how to extend these established gradual-typing concepts to give formal guarantees not only about how to change types as code evolves but also about how to change such programming patterns as well. In particular, we explore mixing untyped "structural" code with typed "nominal" code in an object-oriented language. But whereas previous work only allowed "nominal" objects to be treated as "structural" objects, we also allow "structural" objects to dynamically acquire certain nominal types, namely interfaces. We present a calculus that supports such "cross-paradigm" code migration and interoperation in a manner satisfying both the static and dynamic gradual guarantees, and demonstrate that the calculus can be implemented efficiently.

Simulation of the Fluid–Structure Interaction in Fishing Nets

The main objective of this work is the development of a Computational Fluid Dynamics model coupled with a structural code for the simulation and optimization of fishing gears. As fishing nets are highly deformable structures under the influence of incident water, the use of merely empirical correlations for hydrodynamic forces, such as those used in many structural codes, does not provide precise predictions for their behaviour. The coupling between the structural problem and the hydrodynamic effects makes it necessary to tackle the problem through a new “fluid–structure interaction” approach, which is described here. Preliminary results obtained with the CFD model are also presented.

Floating Substations for Commercial-Scale Floating Windfarms

As floating wind farms move from pilot projects to commercial-scale installations they will move further offshore and into deeper water. There will be a requirement for offshore substations to deliver the electricity to shore, for which floating support structures will be the preferred solution. This paper describes the challenges and development of solutions for commercial-scale HVAC and HVDC floating offshore substations. Two different floating substation concepts have been developed. Layouts for the electrical and ancillary equipment were initially developed, to enable efficient packaging and structural efficiency for the topsides. By integrating the hull and topsides, the overall mass of the structure is minimised, benefitting stability and reducing hull size. Hydrodynamic analysis of the substructures was performed and structural code checks on the hull and topsides were carried out in Sesam. Mooring designs for each structure for 250m water depth have been developed and analysed in Orcaflex. It is likely that alternating current (HVAC) export to shore will be used for shorter transmission distances and direct current (HVDC) will be used for longer transmission distances. HVDC and HVAC floating substations will have quite different hull forms. The larger topsides footprint and greater mass of the HVDC conversion equipment make a conventional semi-submersible hull form efficient when allied to a stressed-skin topsides structure. The smaller footprint, lighter weight and differing requirements for protection from the elements of the HVAC topsides make this inefficient, so a deep draught semi-submersible with a hybrid topsides is the preferred solution. It is concluded that floating substations suitable for large, commercial-scale wind farms will be the chosen solution for anything other than shallow water or close to shore.

Timber bodies strength of materials: Fundamental principles, test specimens proposal

<p>To reduce the economic cost of a Timber Structure, the first condition is to have a “rational” Structural Code, that is, a Code supported by research and a specific theory. To establish a rational Structural Timber Code, a specific theoretical support is needed. The objective of this paper is to cooperate in the construction of this theoretical support. To design timber structures, it is necessary to have mathematical models able to reproduce the resistance of timber bodies under different solicitations. In this paper, a “road map” to arrive to a specific Strength of Materials of Timber Bodies is proposed. This theory will be the tool needed to develop the mathematical models whose quantification will be obtained by testing “basic test specimens” obtained from timber of any particular timber building (like in concrete or soil mechanics). Finally, a “basic test specimen” for practical application of the theory is proposed. In this case, the experimental support is referred to “willow” wood.</p>

Identification of Co-Changed Classes in Software Applications Using Software Quality Attributes

When changes are made to software applications often, defects can occur in software applications, and eventually leads to expensive operational faults. Comprehensive testing is not feasible with the limited time and resources available. There is a need for test case selection and prioritization so that testing can be completed with maximum confidence in a minimum time. Advance knowledge of co-changed classes in software applications can be very useful during the software maintenance phase. In this article, the authors have proposed a co-change prediction model based upon the combination of structural code measures and dynamic revision history from change repository. Univariate analysis is applied to identify the useful measures in co-change identification. The proposed model is validated using eight open source software applications. The results are promising and indicate that they can be very beneficial in maintenance of software applications.

ANNOTATING AND EXPLORING CODE-SWITCHING IN FOUR CORPORA OF MINORITY LANGUAGES OF RUSSIA

This paper describes code-switching with Russian in four spoken corpora of minority languages of Russia: two Uralic ones (Hill Mari and Moksha) and two Tungusic ones (Nanai and Ulch). All narrators are bilinguals, fluent both in the indigenous language (IL) and in Russian; all the corpora are comparable in size and genres (small field collections of spontaneous oral texts, produced under the instruction to speak IL); the languages are comparable in structural (dis)similarity with Russian. The only difference concerns language dominance and the degree of language shift across the communities. The aim of the paper is to capture how the degree of language shift influences the strategy of code-switching attested in each of the corpora using a minimal additional annotation of code-switching. We added to each corpus a uniform annotation of code-switching of two types: first, a simple semi-automatic word-by-word language annotation (IL vs. Russian), second, a manual annotation of structural code-switching types (for smaller sub-corpora). We compared several macro-parameters of code-switching by applying some existing simple measures of code-switching to the data of annotation 1. Then we compared the rates of different structural types of code-switching, basing on annotation 2. The results of the study, on the one hand, verify and enhance the existing generalizations on how language shift influences code-switching strategies, on the other hand, they show that even a very simple annotation of code-switching integrated to an existing field records collection appears to be very informative in code-switching studies.

Model of Early Stage Intermediate in Respect to Its Final Structure

The model, describing a method of determining the structure of an early intermediate in the process of protein folding to analyze nonredundant PDB protein bases, allows determining the relationship between the sequence of tetrapeptides and their structural forms expressed by structural codes. The contingency table expressing such a relationship can be used to predict the structure of polypeptides by proposing a structural form with a precision limited to the structural code. However, by analyzing structural forms in native forms of proteins based on the fuzzy oil drop model, one can also determine the status of polypeptide chain fragments with respect to the assumptions of this model. Whether the probability distributions for both compliant and noncompliant forms were similar or whether the tetrapeptide sequences showed some differences at a level of a set of structural codes was investigated. The analysis presented here indicated that some sequences in both forms revealed differences in probability distributions expressed as a negative statistically significant correlation coefficient. This meant that the identified sections (tetrapeptides) took different forms against the fuzzy oil drop model. It may suggest that the information of the final status with respect to hydrophobic core formation is already carried by the structure of the early-stage intermediate.