748 resultados para Construction industry - Economic aspects - China
Resumo:
Many planning and control tools, especially network analysis, have been developed in the last four decades. The majority of them were created in military organization to solve the problem of planning and controlling research and development projects. The original version of the network model (i.e. C.P.M/PERT) was transplanted to the construction industry without the consideration of the special nature and environment of construction projects. It suited the purpose of setting up targets and defining objectives, but it failed in satisfying the requirement of detailed planning and control at the site level. Several analytical and heuristic rules based methods were designed and combined with the structure of C.P.M. to eliminate its deficiencies. None of them provides a complete solution to the problem of resource, time and cost control. VERT was designed to deal with new ventures. It is suitable for project evaluation at the development stage. CYCLONE, on the other hand, is concerned with the design and micro-analysis of the production process. This work introduces an extensive critical review of the available planning techniques and addresses the problem of planning for site operation and control. Based on the outline of the nature of site control, this research developed a simulation based network model which combines part of the logics of both VERT and CYCLONE. Several new nodes were designed to model the availability and flow of resources, the overhead and operating cost and special nodes for evaluating time and cost. A large software package is written to handle the input, the simulation process and the output of the model. This package is designed to be used on any microcomputer using MS-DOS operating system. Data from real life projects were used to demonstrate the capability of the technique. Finally, a set of conclusions are drawn regarding the features and limitations of the proposed model, and recommendations for future work are outlined at the end of this thesis.
Resumo:
The control needed in the management of a project was analysed with particular reference to the unique needs of the construction industry within the context of site management. This was explored further by analysing the various problems facing managers within the overall system and determining to what extent the organisation would benefit from an integrated mangement information system. Integration and management of information within the organisational units and the cycles of events that make up the main sub-system was suggested as the means of achieving this objective. A conceptual model of the flow of information was constructed within the whole process of project management by examining the type of information and documents which are generated for the production cycle of a project. This model was analysed with respect to the site managers' needs and the minimum requirements for an overall integrated system. The most tedious and time-consuming task facing the site manager is the determination of weekly production costs, calculation and preparation of interim certificates and valuation of variations occurring during the production stage and finally the settlement and preparation of supplier and sub-contractors' accounts. These areas where microcomputers could be of most help were identified and a number of packages were designed and implemented for various contractors. The gradual integration of stand-alone packages within the whole of the construction industry is a logical sequence to achieve integration of management system. The methods of doing this were analysed together with the resulting advantages and disadvantages.
Building up resilience of construction sector SMEs and their supply chains to extreme weather events
Resumo:
Wider scientific community now accept that the threat of climate change as real and thus acknowledge the importance of implementing adaptation measures in a global context. In the UK , the physical effects of climate change are likely to be directly felt in the form of extreme weather events, which are predicted to escalate in number and severity in future under the changing climatic conditions. Construction industry; which consists of supply chains running across various other industries, economies and regions, will also be affected due to these events. Thus, it is important that the construction organisations are well prepared to withstand the effects of extreme weather events not only directly affecting their organisations but also affecting their supply chains which in turn might affect the organisation concerned. Given the fact that more than 99% of construction sector businesses are SMEs, the area can benefit significantly from policy making to improve SME resilience and coping capacity. This paper presents the literature review and synthesis of a doctoral research study undertaken to address the issue of extreme weather resilience of construction sector SMEs and their supply chains. The main contribution of the paper to both academia and practitioners is a synthesis model that conceptualises the factors that enhances resilience of SMEs and their supply chains against extreme weather events. This synthesis model forms the basis of a decision making framework that will enable SMEs to both reduce their vulnerability and enhance their coping capacity against extreme weather. The value of this paper is further extended by the overall research design that is set forth as the way forward.
Resumo:
Intranet technologies accessible through a web based platform are used to share and build knowledge bases in many industries. Previous research suggests that intranets are capable of providing a useful means to share, collaborate and transact information within an organization. To compete and survive successfully, business organisations are required to effectively manage various risks affecting their businesses. In the construction industry too this is increasingly becoming an important element in business planning. The ability of businesses, especially of SMEs which represent a significant portion in most economies, to manage various risks is often hindered by fragmented knowledge across a large number of businesses. As a solution, this paper argues that Intranet technologies can be used as an effective means of building and sharing knowledge and building up effective knowledge bases for risk management in SMEs, by specifically considering the risks of extreme weather events. The paper discusses and evaluates relevant literature in this regard and identifies the potential for further research to explore this concept.
Resumo:
China’s long term development path has always been strongly infl uenced by its own ways of innovation and invention. Though around one thousand years ago China had been undoubtedly the most advanced country in the world, by the 17th century Europe had surpassed it. And when the PRC was founded in 1949, it was only a poor, severely underdeveloped country without adequate, modern technologies. In the last three decades, however, the country has achieved remarkable success in economic terms: China has become the second largest economy in the world, and its new economic, fi nancial and trading power has made it clear that the dominance of the USA and Europe has passed. At the same time China is still lagging behind technologically. Though there are huge efforts to narrow the gap, it is extremely diffi cult to build up a new technological and innovation system without deep, organic foundations. China, however, has rich experience of innovations from the past, and the question is whether it is possible to use them to formulate a new technology policy. In this paper I will try to examine China’s technology system, its functioning and its prospects, while comparing it with the traditional ways of innovations in China. I would like to show that current technology policy is, at least partly, based upon traditional values, and that high tech research, R&D, and state of the art innovations can be reconcilable with several thousand-year-old approaches.
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The purpose of this study was to recast Miami's social history during the first three decades of the twentieth century through an examination of working class life. The thesis attempts to fill a gap in the literature while also expanding on the advances made in race and class studies of the United States. Through an analysis of local newspapers, minutes of a carpenter's union, and other archival sources, the thesis demonstrates how white workers obtained a virtual monopoly in skilled jobs over black workers, particularly in the construction industry, and exacted economic pressure on business through the threat of work stoppages. Driven by the concern to maintain smooth and steady growth amidst a vibrant tourist economy, business reluctantly worked with labor to maintain harmonious market conditions. Blacks, however, were able to gain certain privileges in the labor market through challenging the rigid system of segregation and notions of what constituted skilled labor. The findings demonstrate that Miami's labor unions shaped the city's social, cultural, and political landscape but the extent of their power was limited by booster discourse and the city's dependence on tourism. ^
Resumo:
The outcome of this research is an Intelligent Retrieval System for Conditions of Contract Documents. The objective of the research is to improve the method of retrieving data from a computer version of a construction Conditions of Contract document. SmartDoc, a prototype computer system has been developed for this purpose. The system provides recommendations to aid the user in the process of retrieving clauses from the construction Conditions of Contract document. The prototype system integrates two computer technologies: hypermedia and expert systems. Hypermedia is utilized to provide a dynamic way for retrieving data from the document. Expert systems technology is utilized to build a set of rules that activate the recommendations to aid the user during the process of retrieval of clauses. The rules are based on experts knowledge. The prototype system helps the user retrieve related clauses that are not explicitly cross-referenced but, according to expert experience, are relevant to the topic that the user is interested in.
Resumo:
Considered as one of the oldest activities done by men, the civil construction represents one of the most important sectors for the economic growth of a country, in spite of the low results of growth in the past few years and also in the current year. To make this industry grow, even with an unfavourable economic scenario, it is necessary to implement an effective planning in its activities. This is one of the most important concepts brought by the Lean Construction philosophy, which had its origin through the adaptation of the concepts established by the Toyota Production System (TPS) or Lean Production. By having as a scenario the city of Natal\RN, the main goal of this dissertation consists in investigating how the 11 principles of the lean construction influenced the schedule of a construction field that started to implement its lean concepts. As a methodology, it was used the case study of a big enterprise located in Natal (RN). During the execution of the method, documents related to the short-term, midterm and long-term planning were analysed , aiming to describe its planning process; it was also described the factors that caused the delays at the enterprises’ field ;in addition, a comparison was made between the results obtained at the case study and the ones presented at the literature; in the end, the actions were listed by the company, which had the purpose to solve the main causes of delays, verifying if they were linked to the lean construction principles. This research finds its reason of existence in the relevance of its theme at the nowadays reality of the construction industry, since the principles of the lean construction uphold the reduction of processes that are useless, diminishing wastes as well as costs in construction. The relevance is perceived for the academy, in terms of the possibility to discuss if the concepts established by the lean production are being adapted to the civil construction sector and how this adaptation is influencing at the buildings planning project. Economic importance, because with the reduction of the wastes and costs, the companies may reduce the building´s value into a more accessible value, even with the sector´s lower growth. And social significance, because lean construction gives a better participation of the labour at the planning activity. Among the main results, the high frequency of planning errors stands out, mainly the programming deviations and not the task programming, as well as the execution errors, low productivity and activities executed by the workers. Amongst the 11 principles of lean construction, only five were related with the 12 actions analysed by the author. From the 12 actions, four were completely cohesive to one or more from these five principles. Some improvement proposals were also highlighted and established by the research.
Resumo:
Carbon Capture and Storage (CCS) technologies provide a means to significantly reduce carbon emissions from the existing fleet of fossil-fired plants, and hence can facilitate a gradual transition from conventional to more sustainable sources of electric power. This is especially relevant for coal plants that have a CO2 emission rate that is roughly two times higher than that of natural gas plants. Of the different kinds of CCS technology available, post-combustion amine based CCS is the best developed and hence more suitable for retrofitting an existing coal plant. The high costs from operating CCS could be reduced by enabling flexible operation through amine storage or allowing partial capture of CO2 during high electricity prices. This flexibility is also found to improve the power plant’s ramp capability, enabling it to offset the intermittency of renewable power sources. This thesis proposes a solution to problems associated with two promising technologies for decarbonizing the electric power system: the high costs of the energy penalty of CCS, and the intermittency and non-dispatchability of wind power. It explores the economic and technical feasibility of a hybrid system consisting of a coal plant retrofitted with a post-combustion-amine based CCS system equipped with the option to perform partial capture or amine storage, and a co-located wind farm. A techno-economic assessment of the performance of the hybrid system is carried out both from the perspective of the stakeholders (utility owners, investors, etc.) as well as that of the power system operator.
In order to perform the assessment from the perspective of the facility owners (e.g., electric power utilities, independent power producers), an optimal design and operating strategy of the hybrid system is determined for both the amine storage and partial capture configurations. A linear optimization model is developed to determine the optimal component sizes for the hybrid system and capture rates while meeting constraints on annual average emission targets of CO2, and variability of the combined power output. Results indicate that there are economic benefits of flexible operation relative to conventional CCS, and demonstrate that the hybrid system could operate as an energy storage system: providing an effective pathway for wind power integration as well as a mechanism to mute the variability of intermittent wind power.
In order to assess the performance of the hybrid system from the perspective of the system operator, a modified Unit Commitment/ Economic Dispatch model is built to consider and represent the techno-economic aspects of operation of the hybrid system within a power grid. The hybrid system is found to be effective in helping the power system meet an average CO2 emissions limit equivalent to the CO2 emission rate of a state-of-the-art natural gas plant, and to reduce power system operation costs and number of instances and magnitude of energy and reserve scarcity.
Resumo:
From humble beginnings less than twenty years ago, the economic relationship between Canada and the Chinese has flourished so that China is now Canada’s second most important trading partner after the United States. The Chinese demand for Canada’s exports, in particular in the natural resource sectors, has been a clear win for Canada, especially during the recent Great Recession where demand from other countries dropped sharply. But other aspects of the relationship have led to suggestions of costs. Canada’s large trade deficit with China at least looks superficially as a drag on the Canadian economy. It has been suggested the greater exposure to a low cost producer has displaced Canadian production and jobs and lowered wages. We find that each argument for costs to the relationship ignores important factors. On balance we conclude the relationship has been good for Canada, and it could be even better in the future.
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There is an increasing need for a comprehensive institutional understanding pertaining to ecosystem services (ESs) in coastal and marine fields. This paper develops a systematic framework to inform coastal and marine governance about the integration of ES concepts. First, as a theoretical basis, we analyze the generic rules that are part of the Institutional Analysis and Development (IAD) framework. Second, by an extensive literature review, we formulate a set of ES-specific rules and develop an evaluative framework for coastal and marine governance. Third, we examine this evaluative framework in a specific action situation, namely coastal strategic planning concerning Qingdao, China. Results from the literature review and the case study reveal that when designing ES-specific rules for coastal and marine governance, there are several socio-spatial and economic aspects that should be taken into account: (1) conceive of stakeholders as ES users, (2) capture the effect of ecological scaling, (3) understand ES interactions and clarify indirect impacts and causalities, (4) account for ES values, and (5) draw on economic choices for use rights to deal with ES issues.
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This article deals with several international instruments which provide legal guarantees for media diversity, which is essential for the promotion of cultural diversity. Based on several articles of the Convention of cultural diversity, the General Comment of the Committee on Economic, Social and Cultural Rights No. 21 on the right to take part in cultural life, as well as the work of the UN Independent Expert on Cultural Rights, this article aims to identify legal tools for the establishing of measures promoting cultural diversity in the media. This article looks at the case study of Honduran Garifuna community radios. It emphasizes the importance of taking into account the economic aspects of cultural and communicational rights.
Resumo:
The construction industry is one of the largest consumers of raw materials and energy and one of the highest contributor to green-houses gases emissions. In order to become more sustainable it needs to reduce the use of both raw materials and energy, thus lim-iting its environmental impact. Developing novel technologies to integrate secondary raw materials (i.e. lightweight recycled aggre-gates and alkali activated “cementless” binders - geopolymers) in the production cycle of concrete is an all-inclusive solution to im-prove both sustainability and cost-efficiency of construction industry. SUS-CON “SUStainable, Innovative and Energy-Efficiency CONcrete, based on the integration of all-waste materials” is an European project (duration 2012-2015), which aim was the inte-gration of secondary raw materials in the production cycle of concrete, thus resulting in innovative, sustainable and cost-effective building solutions. This paper presents the main outcomes related to the successful scaling-up of SUS-CON concrete solutions in traditional production plants. Two European industrial concrete producers have been involved, to design and produce both pre-cast components (blocks and panels) and ready-mixed concrete. Recycled polyurethane foams and mixed plastics were used as aggre-gates, PFA (Pulverized Fuel Ash, a by-product of coal fuelled power plants) and GGBS (Ground Granulated Blast furnace Slag, a by-product of iron and steel industries) as binders. Eventually, the installation of SUS-CON concrete solutions on real buildings has been demonstrated, with the construction of three mock-ups located in Europe (Spain, Turkey and Romania)
Resumo:
In the near future, geopolymers or alkali-activated cementitious materials will be used as new high-performance construction materials of low environmental impact with a reasonable cost. This material is a good candidate to partially replace ordinary portland cement (OPC) in concrete as a major construction material that plays an outstanding role in the construction industry of different structures. Geopolymer materials are inorganic polymers based on alumina and silica units; they are synthesized from a wide range of dehydroxylated alumina-silicate powders condensed with alkaline silicate in a highly alkaline environment. Geopolymeric materials can be produced from a wide range of alumina-silica, including natural products--such as natural pozzolan and metakaolin--or coproducts--such as fly ash (coal and lignite), oil fuel ash, blast furnace or steel slag, and silica fume--and provide a route toward sustainable development. Using lesser amounts of calcium-based raw materials, lower manufacturing temperature, and lower amounts of fuel result in reduced carbon emissions for geopolymer cement manufacture up to 22 to 72% in comparison with portland cement. A study has been done by the authors to investigate the intrinsic nature of different types of Iranian natural pozzolans to determine the activators and methods that could be used to produce a geopolymer concrete based on alkali-activated natural pozzolan (AANP) and optimize mixture design. The mechanical behavior and durability of these types of geopolymer concrete were investigated and compared with normal OPC concrete mixtures cast by the authors and also reported in the literature. This paper summarizes the main conclusions of the research regarding pozzolanic activity, activator properties, engineering and durability properties, applications and evaluation of carbon footprint, and cost for AANP concrete.
Resumo:
Purpose – Employee turnover entails considerable costs and is a major problem for the construction industry. By creating an extensive framework, this study aims to examine whether perceived work-related factors affect turnover intention in South Korean construction companies. Research design – The paper is based on the results of a questionnaire of 136 employees that was conducted and provided by a Korean construction company. Research hypotheses were tested via correlation analyses. The most influencing work-related factors, as well as differences among job levels, were determined by multiple regression analyses. Findings – Communication, immediate leaders, organizational commitment, and organizational pride substantially affect turnover intentions. All of these factors can be considered as relational factors. The most influencing factors differ among job levels. Discussion/practical implications – Immediate leaders should be aware of their role in retaining employees and enhance communication, organizational commitment and pride. This study shows how the importance of certain variables differs for groups of employees. Theoretical implications/limitations– This study is based on a sample of employees from a Korean construction company. Therefore, the generalizability of the findings has to be tested. Future research should test the proposed framework with other factors or resources. Originality/value – This study shed light on the turnover subject in the South Korean construction industry. It shows that different factors can influence turnover intention among job levels. A framework was created, which is based on 16 work-related factors including organizational factors, HRM practices and job attitudes.