41 research outputs found

    Energy-minimizing torus-valued maps with prescribed singularities, Plateau's problem, and BV-lifting

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    In this paper, we investigate the relation between energy-minimizing torus-valued maps with prescribed singularities, the lifting problem for torus-valued maps in the space BV, and Plateau's problem for vectorial currents, in codimension one. First, we show that the infimum of the W1,1W^{1,1}-seminorm among all maps with values in the kk-dimensional flat torus and prescribed topological singularities SS is equal to the minimum of the mass among all normal\textit{normal} Rk\mathbb{R}^k-currents, of codimension one, bounded by SS. Then, we show that the minimum of the BVBV-energy among all liftings of a given torus-valued W1,1W^{1,1}-map u\textbf{u} can be expressed in terms of the minimum mass among all integral\textit{integral} Zk\mathbb{Z}^k-currents, of codimension one, bounded by the singularities of u\textbf{u}. As a byproduct of our analysis, we provide a bound for the solution of the integral Plateau problem, in codimension one, in terms of Plateau's problem for normal currents.Comment: 42 page

    Capital diversion in Vietnamese state-owned enterprises

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    Purpose – The authors estimated the hidden overhead (capital diversion or wasteful use of capital) of Vietnam state-owned enterprises (SOEs). Design/methodology/approach – The authors used a panel data set of 10,200 Vietnam SOEs observed over the period 2010–2018. The authors modeled and estimated the hidden overhead by using a stochastic production frontier. The hidden overhead parameter is modelled as the technical inefficiency in the production function. Findings – Vietnam SOEs are very capital intensive. The hidden overhead (or the wasteful use of capital) is very high with an average rate of 69%. Research limitations/implications – Alternative estimation methods should be used to account for endogeneity in production inputs. Lack of comparison with the Vietnam private firms. Originality/value – The paper proposes an original way to quantify hidden overhead (or capital diversion) in the Vietnam SOEs. The finding (a capital diversion rate of 69% on average) is astonishing. It calls for an urgent and profound reform of the Vietnam SOEs

    Epidemiological and molecular characteristics of Infectious bursal disease virus naturally infected in the broiler flocks in the Mekong Delta of Vietnam during 2015 and 2018

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    Infectious bursal disease is a highly contagious and economically devastating disease in the poultry industry worldwide caused by Infectious bursal disease virus (IBDV). However, the data on epidemiological and molecular characteristics of the IBDV outbreak in broiler flocks in the Mekong Delta of Vietnam is unclear. Herein, the epidemiological data of IBDV–positive flocks over a period of 2015–2018 were recorded and the hypervariable region of the VP2 gene of IBDV was amplified to analyze the local phylogeny. The current investigation showed that the overall morbidity and mortality rates of IBDV–positive flocks were 45% and 4.81%, respectively. The IBDV–positive birds occurred clinical signs and macroscopic findings involved with the very virulent (vv) IBDV outbreak. Epidemiological results revealed that IBDV was frequently infected in broiler flocks at 12–42 days, and birds belonging to Tau Vang and Binh Dinh breeds were more sensitive to IBDV. Also, the morbidity rate of IBDV was dramatically decreased in the open farming system. Flocks with complete vaccination significantly dropped morbidity in comparison with other groups. Regarding phylogenetic analysis, all identified IBDV sequences clustered in the same branch of vv phenotype and closely homology with prior strains circulated in Vietnam and other countries. These findings first indicated the epidemiological characteristics of the IBDV–positive broiler flocks in the Mekong Delta and highlighted the IBDV strain circulating in this region

    Factors Influencing Cost Overruns in Construction Projects of International Contractors in Vietnam

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    A construction project is a designed product made up of labors, materials, and installations in the project positioned on the ground and may include the underground and ground section, and the section in water or on the water surface. It is a civil, industrial, transport, agricultural and rural development, infrastructure, or some other. A key phase in the life cycle of these construction projects is the implementation when building products are made directly with workers, equipment, materials, and managers. If there is a lack of management experience, information, and problem-solving solutions to tackle the risks faced by contractors, especially foreign ones, will fail in controlling the project’s cost. This study was conducted with investigations, discussions, and evaluation of the factors that lead to cost overruns in the construction projects of international contractors in Vietnam. The principal component analysis (PCA) showed that those factors that influence cost overruns these construction projects fall into five general groups, including factors related to (i) the owners, (ii) the foreign contractors, (iii) the subcontractors and suppliers, (iv) state management, and (v) the project itself. Besides, the study proposes solutions to limit cost overruns in construction projects and improve the profitability of international contractors in Vietnam

    Exploring Critical Risk Factors of Office Building Projects

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    Risks and uncertainty are unavoidable problems in management of projects. Therefore, project managers should not only prevent risks, but also have to respond and manage them. Risk management has become a critical interest subject in the construction industry for both practitioners and researchers. This paper presents critical risk factors of office building projects in the construction phase in Ho Chi Minh City, Vietnam. Data was collected through a questionnaire survey based on the likelihood and consequence level of risk factors. These factors fell into five groups: (i) financial risk factors; (ii) management risk factors; (iii) schedule risk factors; (iv) construction risk factors; and (v) environment risk factors. The research results showed that critical factors affecting office building projects are natural (i.e., prolonged rain, storms, climate effects) and human-made issues (i.e., soil instability, safety behaviors, owner’s design change) and the schedule-related risk factors contributed to the most significant risks for office buildings projects in the construction phase in Ho Chi Minh City. They give construction management and project management practitioners a new perspective on risks and risk management of office buildings projects in Ho Chi Minh City and are proactive in the awareness, response, and management of risk factors comprehensively
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