438 research outputs found
Dynamic correlation between stock market and oil prices: The case of oil-importing and oil-exporting countries
The paper investigates the time-varying correlation between stock market prices and oil prices for oil-importing and oil-exporting countries. A DCC-GARCH-GJR approach is employed to test the above hypothesis based on data from six countries; Oil-exporting: Canada, Mexico, Brazil and Oil-importing: USA, Germany, Netherlands. The contemporaneous correlation results show that i) although time-varying correlation does not differ for oil-importing and oil-exporting economies, ii) the correlation increases positively (negatively) in respond to important aggregate demand-side (precautionary demand) oil price shocks, which are caused due to global business cycle’s fluctuations or world turmoil (i.e. wars). Supply-side oil price shocks do not influence the relationship of the two markets. The lagged correlation results show that oil prices exercise a negative effect in all stock markets, regardless the origin of the oil price shock. The only exception is the 2008 global financial crisis where the lagged oil prices exhibit a positive correlation with stock markets. Finally, we conclude that in periods of significant economic turmoil the oil market is not a safe haven for offering protection against stock market losses
The impact of dividend announcements on share price and trading volume: empirical evidence from the Gulf Cooperation Council (GCC) countries
This paper investigates the stock market response to dividend announcements in high growth emerging markets of Gulf countries. Our sample includes 1092 dividend announcements from 299 listed firms over the period 2010 - 2015. In the environment where there is an absence of capital gain and income tax, we find some evidence for the stock price reaction that partly supports the signaling hypothesis. Our findings show that the GCC market is inefficient because of the leakage information before the announcement in bad news, and the delay of share price adjustment in good news. In addition, we report significant trading volume reaction in all the three announcements clusters, where dividends increase, decrease, and are constant, lending support to the hypothesis that the dividend change announcements have an impact on the trading volume response due to different investors’ preferences. These results are highly recommended to financial analysts and investors dealing with the GCC market
Share price informativeness and dividend smoothing behavior in GCC markets
This paper examines the dividend smoothing behaviour in Gulf Cooperation Council (GCC) countries, in emerging markets where the response to news and the economic environment are different from those of developed countries. We examine the effect of share price informativeness on dividend smoothing in the (GCC) markets, using an unbalanced panel data for a sample of 628 GCC-listed firms during 1994-2016. For the regression analysis, the hypotheses are tested using panel regressions and GMM estimation. The empirical results can be summarised in the following manner: First, the Lintner model shows that the dividend smoothing degree in GCC firms is comparable to that of a developed market. Second, and importantly, the results reveal that the dividend smoothing in GCC firms is sensitive to private information of share prices. Finally, the findings indicate that information asymmetry and agency-based models affect the tendency to smooth dividends in the GCC markets
Loss of information during design & construction for highways asset management: A geobim perspective
Modern cities will have a catalytic role in regulating global economic growth and development, highlighting their role as centers of economic activity. With urbanisation being a consequence of that, the built environment is pressured to withstand the rapid increase in demand of buildings as well as safe, resilient and sustainable transportation infrastructure. Transportation Infrastructure has a unique characteristic: it is interconnected and thus, it is essential for the stakeholders to be able to capture, analyse and visualise these interlinked relationships efficiently and effectively. This requirement is addressed by an Asset Information Management System (AIMS) which enables the capture of such information from the early stages of a transport infrastructure construction project. Building Information Modelling (BIM) and Geographic Information Science/Systems (GIS) are two domains which facilitate the authoring, management and exchange of asset information by providing the location underpinning, both in the short term and through the very long lifespan of the infrastructure. These systems are not interoperable by nature, with extensive Extract/Transform/Load procedures required when developing an integrated location-based Asset Management system, with consequent loss of information. The purpose of this paper is to provide an insight regarding the information lifecycle during Design and Construction on a Highways Project, focusing on identifying the stages in which loss of information can impact decision-making during operational Asset Management: (i) 3D Model to IFC, (ii) IFC to AIM and (iii) IFC to 3DGIS for AIM. The discussion highlights the significance of custom property sets and classification systems to bridge the different data structures as well as the power of 3D in visualizing Asset Information, with future work focusing on the potential of early BIM-GIS integration for operational AM
IMPACT OF INFORMATION MANAGEMENT DURING DESIGN & CONSTRUCTION ON DOWNSTREAM BIM-GIS INTEROPERABILITY FOR RAIL INFRASTRUCTURE
The need for efficient and sustainable infrastructure – always critical to a city – is further gaining momentum as urbanisation creates the challenge of sustainably designing, constructing and operating the built environment. The AECOO industry, directly responsible for addressing this challenge, has adopted the use of BIM and GIS to aid in this endeavour. Both BIM and GIS overlap with respect to capturing aspects of the built environment, but are not interoperable by nature. To ensure a consistent and structured way of managing the information produced within these environments, industry standards such as IFC are implemented. Research to date focuses on addressing the integration between BIM and GIS for buildings by delving into the IFC and CityGML interoperability, which has highlighted significant geometric and semantic barriers that in the stage of integration, cannot be easily manoeuvred. The purpose of this paper is to provide an insight regarding the information lifecycle during Design & Construction in the HS2 Rail Infrastructure project and investigate the impact of current information management processes – and in particular Standards such as IFC, – on BIM-GIS interoperability and lifecycle management of an asset. Results demonstrate the levels of mis mapping during the export to IFC which varies depending on the infrastructure asset type. Discussion shows that these can be addressed by the introduction of additional semantic property sets to facilitate downstream BIM-GIS interoperability for O & M, enabling scope for future work
Developing IFC for infrastructure: A case study of three highway entities
Modern cities pay particular attention to upscale their infrastructure systems in order to improve the every-day life of their citizens and lead the way towards a more sustainable environment. As part of this, they invest extensive funds in large infrastructure projects which are challenging to deliver as they require an e efficient communication among different professions, in order to share information efficiently throughout the lifecycle of the project, thus highlighting the importance of standardization to maintain consistency and integrity during data exchange. Building Information Modelling (BIM) aims to facilitate the above-mentioned requirements by describing the life-cycle of the project and Industry Foundation Classes (IFC) is the Standard for BIM that enables an efficient storage, management, exchange and visualization of information. However, there are two important challenges that need to be addressed: (i) IFC focuses particularly on buildings and provides limited support for infrastructure elements and (ii) the information exchange aims to describe mostly the construction phase; highlighting the lack of classes that refer to the operation and maintenance phase. Within this context, this paper proposes the extension of Industry Foundation Classes (IFC) for Asset Management in Infrastructure. A method is developed based on a case study of three highway entities: (i) retaining wall, (ii) gantry and (iii) bridge and a conceptual extension is presented. The results are further discussed and recommendations regarding future research fields are proposed
INVESTIGATING INTEROPERABILITY CAPABILITIES BETWEEN IFC AND CITYGML LOD 4 – RETAINING SEMANTIC INFORMATION
Applications of 3D City Models range from assessing the potential output of solar panels across a city to determining the best location for 5G mobile phone masts. While in the past these models were not readily available, the rapid increase of available data from sources such as Open Data (e.g. OpenStreetMap), National Mapping and Cadastral Agencies and increasingly Building Information Models facilitates the implementation of increasingly detailed 3D Models. However, these sources also generate integration challenges relating to heterogeneity, storage and efficient management and visualization. CityGML and IFC (Industry Foundation Classes) are two standards that serve different application domains (GIS and BIM) and are commonly used to store and share 3D information. The ability to convert data from IFC to CityGML in a consistent manner could generate 3D City Models able to represent an entire city, but that also include detailed geometric and semantic information regarding its elements. However, CityGML and IFC present major differences in their schemas, rendering interoperability a challenging task, particularly when details of a building’s internal structure are considered (Level of Detail 4 in CityGML). The aim of this paper is to investigate interoperability options between the aforementioned standards, by converting IFC models to CityGML LoD 4 Models. The CityGML Models are then semantically enriched and the proposed methodology is assessed in terms of model’s geometric validity and capability to preserve semantics
Exploring the Potential of NoSQL Databases for a BIM and 3D GIS enabled Location Framework for Construction Digital Twins and the Golden Thread
As digital transformation accelerates in the construction industry, combining data from Building Information Modelling (BIM) and 3D Geographic Information Systems (3DGIS) has become critical for enhanced decision-making across sectors including construction planning, supply chain management, health and safety and sustainable waste disposal. In combination, BIM and GIS underpin a location framework for Digital Twins across these applications. While traditionally relational databases have been used to integrate the data into one system, they face increasing limitations in handling the massive, complex BIM and 3DGIS data. This research investigates the potential of NoSQL databases as an alternative solution. Focusing on MongoDB, the study conducts a systematic performance comparison with the mature relational database, PostgreSQL. BIM and 3DGIS datasets from a live infrastructure construction project are utilised in three experiments assessing direct query, API-based retrieval, and 3D visualisation. The results provide valuable insights into MongoDB’s strengths in managing large spatial data via flexible schemas. However, limitations surface as data complexity and volume increases. Overall, this study concludes that NoSQL databases do offer some advantages for optimising BIM-3DGIS integration for seamless, combined, use, but more work is needed to fully harness their capabilities
Effects of ultrasound on polymeric foam porosity
A variety of materials require functionally graded cellular microstructures whose porosity is engineered to meet specific applications (e.g. mimic bone structure for orthopaedic applications; fulfil mechanical, thermal or acoustic constraints in structural foamed components, etc.). Although a huge variety of foams can be manufactured with homogenous porosity, there are no generic processes for controlling the distribution of porosity within the resulting matrix. Motivated by the desire to create a flexible process for engineering heterogeneous foams, the authors have investigated how ultrasound, applied during the formation of a polyurethane foam, affects its cellular structure. The experimental results demonstrated how the parameters of ultrasound exposure (i.e. frequency and applied power) influenced the volume and distribution of pores within the final polyurethane matrix: the data demonstrates that porosity (i.e. volume fraction) varies in direct proportion to both the acoustic pressure and frequency of the ultrasound signal. The effects of ultrasound on porosity demonstrated by this work offer the prospect of a manufacturing process that can adjust the cellular geometry of foam and hence ensure that the resulting characteristics match the functional requirements
Enhancing e-Infrastructures with Advanced Technical Computing: Parallel MATLAB® on the Grid
MATLAB® is widely used within the engineering and scientific fields as the language and environment for technical computing, while collaborative Grid computing on e-Infrastructures is used by scientific communities to deliver a faster time to solution. MATLAB allows users to express parallelism in their applications, and then execute code on multiprocessor environments such as large-scale e-Infrastructures. This paper demonstrates the integration of MATLAB and Grid technology with a representative implementation that uses gLite middleware to run parallel programs. Experimental results highlight the increases in productivity and performance that users obtain with MATLAB parallel computing on Grids
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