Core-annular flow through a horizontal pipe: hydrodynamic counterbalancing of buoyancy force on core

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known that at the interface between the annular layer and the core waves are present that move with respect to the pipe wall. In the present study the core is assumed to consist of a solid center surrounded by a high-viscosity liquid layer. Using hydrodynamic lubrication theory taking into account the flow in the low-viscosity liquid annular layer and in the high-viscosity liquid core layer the development of the interfacial waves is calculated. They generate pressure variations in the core layer and annular layer that can cause a net force on the core. Steady eccentric core-annular flow is found to be possible

Exploring the canal environment in terms of water, bed sediments and vegetation in a reclaimed floodplain of Northern Italy

The Po plain (Italy) is one of the largest floodplains in Europe that needs environmental restoration. To achieve this goal, the knowledge of the 'environment' (water, bed sediments and vegetation) of the canals crossing such floodplain is necessary. The water flow of the canals was kept low for hydraulic safety purposes from October to March (NIR), and high for irrigation purposes from April to September (IR). Within this framework, this study aimed to assess in 9 sites of the east part of Po plain 1) the canals' environment quality in terms of vegetation diversity, and water and bed sediment physicochemical properties; and 2) how these features are influenced by canal managements and landscape properties. Water was monthly sampled both in NIR and IR periods, the bed sediments were sampled in summer and winter pe-riods, while the vegetation was recorded in spring and autumn. The low water flow during NIR worsened the water quality by increasing the concentrations of nutrients and salts. A higher salt and nutrient concentrations were observed both in water and bed sediments of canals crossing areas with fne texture alluvial deposits than in those flowing through medium texture alluvial deposits. Further, higher nutrient and salt concentrations were observed for the ca-nals used as collectors of the water coming from other canals. Despite the differences observed for the bed sediments and water quality, the vegetation type and biodiversity did not show differences among the study sites probably be-cause affected by the land use of the surrounding landscape. Indeed, the canals cross agricultural land which limit the developments of natural vegetation and do not promote plant biodiversity. Overall, the present study found out the key role of landscape properties and canal managements on 'canal environment' quality which need to be consid-ered to perform an appropriate reclamation of such environments

Experiment-driven development of a GWAP for marking segments in text

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee© 2017 Copyright is held by the owner/author(s). This paper describes TileAttack, an innovative highly configurable game-with-a-purpose (GWAP) designed to gather annotations for text segmentation tasks whilst exploring the effects of different game mechanics on GWAP for NLP (Natural Language Processing) problems, with a view to improving both quality of player contributions and player uptake. In this work we present a pilot experiment that shows TileAttack labelling "mentions" and being used to test the effects of in game time constraints on accuracy and player engagement. We present the results of this experiment using a set of metrics derived from those used for evaluating Free-To-Play (F2P) games

The design of a clicker game for text labelling

Games for text annotation / labelling are becoming more common, but it's difficult to find a mechanics that fits. In this work we discuss a clicker game that can support text annotation. We believe this type of game is uniquely suited to addressing some of the challenges faced by games featuring text annotation as a core task

Using Games to Create Language Resources: Successes and Limitations of the Approach

Abstract One of the more novel approaches to collaboratively creating language resources in recent years is to use online games to collect and validate data. The most significant challenges collaborative systems face are how to train users with the necessary expertise and how to encourage participation on a scale required to produce high quality data comparable with data produced by “traditional ” experts. In this chapter we provide a brief overview of collaborative creation and the different approaches that have been used to create language resources, before analysing games used for this purpose. We discuss some key issues in using a gaming approach, including task design, player motivation and data quality, and compare the costs of each approach in terms of development, distribution and ongoing administration. In conclusion, we summarise the benefits and limitations of using a gaming approach to resource creation and suggest key considerations for evaluating its utility in different research scenarios

Testing game mechanics in games with a purpose for NLP applications

This paper describes a highly configurable game-with-a-purpose (GWAP) designed to explore the effects of different game mechanics on GWAP for NLP problems with a view to improving both quality of annotation and player uptake. The details of the game are discussed along with some of the questions the game hopes to answer

Metrics of games-with-a-purpose for NLP applications

A Game-With-A-Purpose (GWAP) ap- proach is a promising way to collect data on a large scale but its adoption for NLP annotation projects has been slow. In this paper, we propose evaluation metrics adapted from free-to-play (F2P) games to help understand what makes games suc- cessful for NLP applications

A Framework for Interpreting Bridging Anaphora

In this paper we present a novel framework for resolving bridging anaphora.We argue that anaphora, particularly bridging anaphora, is used as a shortcut device similar to the use of compound nouns. Hence, the two natural language usage phenomena would have to be based on the same theoretical framework. We use an existing theory on compound nouns to test its validity for anaphora usages. To do this, we used hu- man annotators to interpret indirect anaphora from naturally occurring discourses. The annotators were asked to classify the relations between anaphor-antecedent pairs into relation types that have been previously used to describe the relations between a modi er and the head noun of a compound noun. We obtained very encouraging results with an average Fleiss's value of 0.66 for inter-annotation agreement. The results were evaluated against other similar natural language interpretation annota- tion experiments and were found to compare well. In order to determine the prevalence of the proposed set of anaphora relations we did a detailed analysis of a subset 20 newspaper articles. The results obtained from this also indicated that a majority (98%) of the relations could be described by the relations in the framework. The results from this analysis also showed the distribution of the relation types in the genre of news paper article discourses