bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Systematic Hull Shape Variations on Ship Stability Performances in Waves
Authors: Petacco Nicola , Vernengo Giuliano , Villa Diego , Coppedé Antonio , Gualeni Paola 
Published: January 2021

Abstract
The sensitivity of ship stability performance in waves to geometric variation has been investigated by means of a simulation-based design framework. The study was devoted to assess the influence of hull geometry variations on some stability failure modes, namely, parametric roll (PR) and pure loss of stability (PLS). The application has been developed by using a representative model of a postpanamax container vessel. PR and PLS phenomena have been investigated by the application of second-generation intact stability criteria (SGISc). The initial multidimensional design space has been filled by 500 design configurations identified by means of a design of experiments approach. A method developed in-house, combining the subdivision surface and free-form deformation approaches, has been used to create the whole set of design alternatives. The generated design configurations have been assessed analyzing the results derived from application of the first- and the second-level SGIS vulnerability criteria for both the selected stability failure modes. To strengthen the correlation behaviors, the design space has then been further explored by using 10k design configurations exploiting the capabilities of a surrogate model–based approximation, relying on a Gaussian process formulation. The study has been focused on the correlations among the variables and the response functions, i.e., the outcomes of the SGIS vulnerability criteria. The significance, in terms of effects, of each geometry shape variable has been investigated. Results have been discussed in the light of the SGISc structure, to provide further insight into this innovative safety framework for a modern approach to intact stability.

Introduction
In the last 10 years, the development of the so-called second-generation intact stability criteria (SGISc) has been one of the most engaging topics addressed by the Sub-Committee on Safety Design and Construction (SDC) of the International Maritime Organization (IMO).
Analysis of Competitiveness in Commercial Shipbuilding
Authors: Hengst Sjoerd , Koppies J. D. M. 
Published: January 2021

The paper consists of two elements:analysis of the competitiveness of the Dutch shipbuilding industry, andstructural and organizational changes in Dutch shipyards since 1983, based on market approach and cost reduction.
The objective of a study completed in 1993 was to gain insight into the competitive position of the Dutch shipbuilding industry for seagoing merchant ships. Different indicators were developed and analyzed for the period 1984–1992. Labor cost and exchange rates are the two parameters which enable assessment of the development of labor cost, which is calculated in U.S.$ per cgt.* For selected countries the level of productivity (and thereby the labor cost per cgt) has been adjusted to an estimated degree of subcontracting. The Netherlands shipbuilding industry shows an average share in the AWES** production of about 8%-9% in the period 1984–1992. This indicates that a competitive position has been maintained. Some Asian countries and Poland show a lower level of labor cost per cgt than the Netherlands. The changes in structure and organization of the Dutch shipbuilding industry, which concentrates mainly on niche markets and special types of vessels, is discussed. The niche-market approach has been leading to product specialization at several yards. The expectations for the shipbuilding market in Western Europe was discussed briefly.* A common measurement of production of the shipbuilding industry is Compensated Gross Tonnage (cgt), which is defined as a unit of shipyard capacity, derived from multiplying the gross tonnage by a coefficient reflecting the "standard man-hour" required for production of the type of ship under consideration. These conversion coefficients give an indication of the required shipbuilding capacity--expressed in man-hours—to produce one gross ton, which takes into account the complexity of the production. If more yard capacity is required to produce one gross ton, the conversion coefficient has a higher value. The conversion coefficients are determined by the working party of the Organization for Economic Cooperation and Development (OECD).** AWES: Association of West European Shipbuilders, including the countries of the European Union (EU) as well as Finland, Sweden and Norway. The national shipbuilders organizations are represented in AWES.
Approach to Accurate Production of Hull Structures
Authors: Okumoto Yasuhisa , Matsuzaki Shin-ichi 
Published: January 2021

The improvement of productivity in response to changes in the labor force--related largely to a decreasing number of skilled workers--has become a major concern of production engineering in shipyards. The following problems were pointed up by an analysis of production tasks:Most work time is wasted in the repair or adjustment of inaccuracies, such as wide gap, lap, or deformation in structural components, which are accumulated at the preassembly stage.lf the accuracy of fabrication and assembly of hull structures is measurably improved, productivity will rise respectively, and effective mechanization and automation of production can be achieved.
The research and development of new hull block production systems based on the above concept--accurate production---have started at lshikawajima-Harima Heavy Industries Co., Ltd. (IHI). Advanced accuracy standards were planned for the new procedure of hull block assembly, and a new "unit-panel and slit process" has been developed and applied at the IHI shipyard. This paper describes the accuracy control system and the new production line at the IHI yard, as well as some key equipment for the installed process.
Plate Residual Stress Effects on Dimensional Accuracy in Thermal Cutting
Authors: Dong P. , Cahill P. , Yang Z. , Mattei N.J. 
Published: January 2021

Dimensional inaccuracies induced by thermal cutting processes have not received sufficient attention in the open literature. A series of recent research initiatives, including this one, have demonstrated that thermal cutting can contribute significantly to dimensional inaccuracies in the form of two major mechanisms:thermally induced part distortions andplate movements as the residual stresses in the original plate are relieved to achieve new equilibrium conditions during cutting. For the former, laser cutting and managing heat sink conditions are effective in minimizing the cutting-induced distortions. For the latter, considerations must be given to the residual stress conditions in the plates to be cut so that a proper cutting sequence and layout plan can be developed to mitigate the plate residual stress effects on part/plate movements during cutting.
In this paper, a major research program recently completed under the auspices of the Gulf Coast Regional Maritime Technology Center will be summarized. Some of the major findings are as follows:Although steel mill processes and parameters vary significantly from mill to mill, the important residual stress features that are relevant to cutting accuracy are dominated by only a few mill process parameters.Localized short-range residual stresses are not detrimental to cutting accuracy, even if the short-range residual stress magnitude can be high. Long-range residual stress distributions that achieve equilibrium conditions at a length scale of plate width are most important for cutting sequence planning purposes.As a result, a generalized residual stress distribution (long range) has been established for cutting planning purposes, although the detailed features may vary from mill to mill.Through a detailed series of parametric analyses using advanced modeling techniques, it was found that cutting sequencing is very important in mitigating the plate residual stress effects.It is important and practical to ensure the consistency in steel conditions so that a set of cutting procedures can be developed for mitigating plate residual stress effects on cutting accuracy, rather than trying to eliminate residual stresses in mill plates.
Model-Based Computational Shipyard Dynamics and Its Applications
Authors: Shin Jong Gye , Kim Youngmin , Jeong Yong-Kuk , Woo Jong Hun , Ryu Cheolho 
Published: January 2021

A ship production system can be represented by various production factors and production management indicators. To manage such a system efficiently, a theory is required to analyze and predict its behavior. The theory should be able to fully express the relationships between production factors and production management indicators. For this purpose, computational shipyard dynamics was proposed by Kim et al. in the Journal of Ship Production and Design (2018). This methodology includes input variables, output variables, and key performance indicator (KPI) functionals, implemented as a simulation model. In this study, a rigorous approach to realize a model of a complex ship production system is presented by embodying previous research. A model-based ship production system theory is defined, which consists of production factors, production management indicators, and the relationships between them, called the simulation-based KPI functionals. The production factors are defined using a six-factor model, and the production management indicators are defined using KPIs that are already used in shipyards so that they are quantitatively measurable. To verify the proposed theory, it was applied to fabrication shop, panel block assembly line, and ship block logistics simulation cases, which are examples that are similar to the job shop, flow shop, and project shop cases, respectively.

Introduction

1.1. Background
Approximately 40% of shipyards worldwide have been closed over the last decade. The reasons for this are the economic recession and intense competition. Inefficiency in the production system is not a big problem in the marine shipping industry and offshore-plant-related industries when these industries are booming with high demands and sufficient funding. However, when crises approach, unrevealed problems emerge, and low productivity leads to catastrophes at shipyards.
Added Masses and Forces on Two Bodies Approaching Central Impact in an Inviscid Fluid
Authors: Landweber L. , Shahshahan A. 
Published: January 2021

An integral-equation procedure has been developed to determine interaction forces on two bodies approaching central impact in an inviscid fluid. The accuracy of the results from that procedure is evaluated by applying it to a pair of circles and a pair of spheres for which exact solutions are available. A second purpose was to refine the procedure so that accurate solutions could be obtained at closer distances between the bodies. In the first part of this work, the classical theory is extended by deriving truncation corrections for the infinite series representing the exact solution and asymptotic formulas for computing interaction forces at small gaps. In the second part, two problems were resolved: one on the treatment of the sharp peaks of the integrands when the gap between the bodies was small, the other on reducing the errors in the numerical differentiation required to evaluate the forces. Results for various combinations of circle pairs, for equal spheres, and for an elliptical cylinder approaching a circular one are presented. A new relation between the interaction forces on a wall and on a body moving normal to it is presented.
Addendum published in 1994 Volume 38, Issue 2 (June), pages 172–173, is included.
A Viscous/Inviscid Interactive Approach for the Prediction of Performance of Hydrofoils and Propellers with Nonzero Trailing Edge Thickness
Authors: Pan Yulin , Pan Yulin 
Published: January 2021

A viscous/inviscid interactive (VII) approach is applied to predict the performance of hydrofoils and propellers with nonzero trailing edge thickness. The emphasis has been put on developing VII models for flow separation. The investigation starts from a two-dimensional (2D) hydrofoil. The current method uses an iterative scheme to find a nonlifting closing extension behind the trailing edge. Two kinds of schemes are applied for the iteration process:a non-lifting extension with 1 or 2 degrees of freedom, in fully wetted condition andan extension which is treated like a cavity surface, but with a nonconstant cavity pressure distribution. The results from these schemes are compared with those from a commercial RANS Solver (Fluent).
Next, the current schemes using flap extensions are extended to three-dimensional (3D) propeller flows. The 3D models are developed so that all the span-wise strips of the propeller satisfy similar conditions to those used in 2D. A propeller with significant nonzero trailing edge thickness is analyzed, using several 3D models, and the results are compared with existing experimental data.
Risk Analysis for Arctic Offshore Operations
Authors: Slomski Stephen , Vivatrat Vitoon 
Published: January 2021

The ice conditions in the Beaufort Sea are very variable, particularly in the deeper water regions. This variability greatly influences the probability of success or failure of an offshore operation. For example, a summer exploratory program conducted from a floating drilling unit may require a period of 60 to 100 days on station. The success of such a program depends on:the time when the winter ice conditions deteriorate sufficiently for the drilling unit to move on station;the number of summer invasions by the arctic ice pack, forcing the drilling unit to abandon station;the rate at which first-year ice grows to the ice thickness limit of the supporting icebreakers; andthe extent of arctic pack expansion during the fall and early winter.
In general, the ice conditions are so variable that, even with good planning, the chance of failure of an offshore operation will not be negligible. Contingency planning for such events is therefore necessary. This paper presents a risk analysis procedure which can greatly benefit the planning of an offshore operation. A floating drilling program and a towing and installation operation for a fixed structure are considered to illustrate the procedure.
Experimental and Numerical Investigation of Bulb Impact with a Ship Side-Shell Structure
Authors: Karlsson Ulf B. , Ringsberg Jonas W. , Johnson Erland , Hoseini Mohammed , Ulfvarson Anders 
Published: January 2021

The finite element (FE) method is suitable as a numerical tool in the numerical analysis of, for example, ship collision scenarios. It is feasible to simulate and compare different collision scenarios by parameter variations. The objective with this investigation was to establish a reliable and robust FE modeling procedure for ship-ship collision simulations, using the commercial FE software Abaqus/Explicit, by means of parameter sensitivity and experimental analyses. Four types of experiments are presented that have supported the development of the FE models and simulations with sufficient information for representation of material characteristics and for validation of models:uniaxial tensile tests,friction tests,bulb impact with a steel-sheet test and, finallya bulb impact with a side-shell ship structure.
The outcome of the parameter study after calibration against test results was two validated FE models: one of the bulb-sheet test and one of the bulb-structure test.
Does optimism mediate the relationship between Big Five and perceived stress? A study with Spanish adolescents
Authors: Serrano Cristina , Martínez Paula , Murgui Sergio , Andreu Yolanda 
Published: January 2021

Los resultados de investigación han mostrado la existencia de relaciones entre los Cinco Grandes factores de personalidad, Optimismo y Estrés Percibido. El objetivo del estudio es explorar, mediante modelos de ecuaciones estructurales, el posible papel mediador que se ha sugerido podría desempeñar Optimismo en esta relación. También, se explora a través de un análisis multi-grupo la invarianza por sexo de los resultados. Un total de 611 adolescentes españoles completaron de forma anónima los cuestionarios BFQ, LOT-R y PSS. Optimismo se asoció positivamente asociado con los rasgos de personalidad y negativamente con Estrés Percibido. El Estrés se relacionó negativamente con Estabilidad Emocional, Extraversion y Responsabilidad y no mostró asociación alguna con Afabilidad ni con Apertura. Los análisis de mediación revelaron el papel mediador de Optimismo en la relación entre Estabilidad Emocional (mediación parcial), Extraversion y Responsabilidad y Estrés. Estos resultados no variaron por sexo. En conclusión, un perfil básico de personalidad caracterizado por Extraversión, Estabilidad Emocional y Responsabilidad favorecería el desarrollo de expectativas positivas de futuro que representan un predictor proximal de Estrés Percibido. El papel mediador del optimismo puede resultar relevante para el desarrollo de intervenciones focalizadas en reducir los niveles de estrés y, consecuentemente, mejorar el ajuste del adolescente.
Research results have shown the existence of relationships between the Big Five personality factors, Optimism, and Perceived Stress. The aim of this study is to explore the possible mediating role that it has been suggested might play Optimism in this relationship. Structural equation models were conducted to examine the mediating role of Optimism. A multi-group analysis was performed to verify whether the results varied by sex. 611 Spanish adolescents completed anonymously the measures of BFQ, LOT-R and PSS. The findings showed that Optimism was positively associated with the personality traits and negatively with Perceived Stress. Perceived Stress was in turn negatively related to Emotional Stability, Extraversion and Conscientiousness, while it was not correlated with Agreeableness and Openness. Mediation analysis revealed the mediating role of Optimism on the relationship between Emotional Stability (partial mediation), Extraversion, and Conscientiousness, and the Perception of Stress. These findings did not vary by sex. In conclusion, a basic personality profile characterized by Extraversion, Emotional Stability, and Conscientiousness would favor the development of positive future expectations that represent a proximal predictor for Perceived Stress. Optimism mediation may be relevant for the development of interventions focused on reducing stress levels and, consequently, to improve the adolescent's adjustment.
La teoría crítica de la fotografía de Theodor W. Adorno
Authors: Maura Eduardo 
Published: January 2021

Resumen: Entre los pensadores vinculados al Institut für Sozialforschung, Walter Benjamin y Siegfried Kracauer son los más reconocidos en los debates sobre la fotografía y lo fotográfico en la cultura y el arte contemporáneo. Estas notas se proponen ampliar este aspecto de la teoría crítica a partir de la lectura de Theodor W. Adorno desde un punto de vista fotográfico.Abstract: In the debates about photography and the photographic in contemporary art and culture, Walter Benjamin and Siegfried Kracauer are the most recognized Institut für Sozialforschung-related thinkers. These notes aim at broadening this aspect of Critical Theory by reading the works of Theodor W. Adorno from a photographic standpoint.
Comunidad, consolidación urbana y políticas de vivienda social. Una mirada desde Colombia y la ciudad de Tunja, Boyacá / / / \ \ \ Community policies, urban consolidation and social housing. An insight from Colombia and the city of Tunja, Boyacá
Authors: López Blanco Dolly Marelby 
Published: January 2021

Resumen: Las ciudades latinoamericanas presentan múltiples problemáticas urbanas, entre ellas el crecimiento a saltos y los vacíos urbanos que deja la autoconstrucción de viviendas, todo en un marco de desigualdad en la distribución del suelo, con soluciones de planeación insuficientes, alejadas de la realidad de las comunidades, y poco eficaces en la mitigación del déficit de calidad de las viviendas y del hábitat urbano. Se estudia el caso de esta ciudad mediana, el análisis a su política urbana y de vivienda social, la mirada de los gestores públicos y la perspectiva que tiene la comunidad, todo con el fin de encontrar propuestas de mejora que procuren una consolidación del entorno urbano, pensadas desde la unidad barrial y el liderazgo comunitario, que permitan el desarrollo social y no se limiten únicamente a las determinantes físicas.

Palabras clave: Políticas públicas, desarrollo urbano, necesidades humanas, déficit habitacional cualitativo, empoderamiento comunitario, diagnóstico de barrios.

Abstract: Latin American cities present multiple urban problems, among them a growing process in leaps and urban gaps left by the self-construction of houses, all within a framework of inequality in the distribution of land, with insufficient planning solutions, far from the reality of communities, and not very effective in mitigating the quality deficit of housing and urban habitat. The case of this medium-sized city, the analysis of its urban and social housing policy, the gaze of public managers and the perspective of the community are studied to find improvement proposals that seek to consolidate the urban environment, thought from the neighborhood unit and the community leadership, that allow the social development and are not limited only to the physical determinants.

Key words: Public policies, urban development, human needs, qualitative housing deficit, community empowerment, neighborhood diagnosis.
Uso de las redes sociales y la brecha digital en el tejido asociativo inmigrante de España
Authors: Tovar Parra Jenny Carolina , Torralba Vásquez Javier Ernesto 
Published: January 2021

Resumen: Son innumerables las investigaciones que se han realizado en el mundo sobre los efectos y beneficios de las nuevas tecnologías versus población y la ciudad digital en sus análisis y conclusiones consideran que existe una nueva problemática en el mundo a la que se le denominó “brecha digital”. Sin embargo, no se han realizado investigaciones acerca del efecto que tienen las nuevas tecnologías de información y comunicación TICS sobre el tejido asociativo inmigrante de Argelia, Bulgaria, Colombia, Ecuador, Mali, Marruecos, Rumania y Senegal en España. El objetivo principal de esta investigación es determinar la incidencia de las nuevas tecnologías de la información y la comunicación en el tejido asociativo inmigrante en España, así como conocer el uso de éstas en el quehacer cotidiano de las asociaciones y sus implicaciones para las mismas, partiendo de una metodología no experimental, comparativa, descriptiva y de etnografía virtual. En sus conclusiones queda claro que la brecha digital afecta las asociaciones a partir de la diferenciación entre las que tienen acceso a internet, los conocimientos para el acceso y cuentan con contenidos de calidad, de las asociaciones que no.

Palabras clave: Tecnologías de la información, Redes Sociales, Migración.

Abstract: Countless researches have been done in the world on the effects and benefits of the new technologies of information and communication ICT versus population and the digital city in its analysis and conclusions consider that there is a new problematic in the world called "digital divide". However, there are not conducted researches about the effects that ICT has had on the immigrant associations network of Algeria, Bulgaria, Colombia, Ecuador, Mali, Morocco, Romania, and Senegal in Spain. The main objective of this article is to analyze the impact of new information and communication technologies on the immigrant network in Spain, as well as knowing the use of them in the daily work and their implications for them based, starting from a non-experimental, comparative, descriptive and virtual ethnography methodology. In its conclusions is clear that the digital divide affects these associations from the differentiation between those with internet access, the skills to access and the quality on the contents, from those without internet access

Key words: Information Technologies, Social Networks, Migration.