94 research outputs found

    Multi-objective symbiotic organisms optimization for making time-cost tradeoffs in repetitive project scheduling problem

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    Time-cost problems that arise in repetitive construction projects are commonly encountered in project scheduling. Numerous time-cost trade-off approaches, such as mathematical, metaheuristic, and evolutionary methods, have been extensively studied in the construction community. Currently, the scheduling of a repetitive project is conducted using the traditional precedence diagramming method (PDM), which has two fundamental limitations: (1) progress is assumed to be linear from start to finish; and (2) activities in the schedule are connected each other only at the end points. This paper proposes a scheduling method that allows the use of continuous precedence relationships and piece-wise linear and nonlinear activity-time-production functions that are described by the use of singularity functions. This work further develops an adaptive multiple objective symbiotic organisms search (AMOSOS) algorithm that modifies benefit factors in the basic SOS to balance exploration and exploitation processes. Two case studies of its application are analyzed to validate the scheduling method, as well as to demonstrate the capabilities of AMOSOS in generating solutions that optimally trade-off minimizing project time with minimizing the cost of non-unit repetitive projects. The results thus obtained indicate that the proposed model is feasible and effective relative to the basic SOS algorithm and other state-of-the-art algorithms

    A new species of the genus Halicyclops (Copepoda, Cyclopoida, Cyclopidae) from freshwater in Central Vietnam

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    A new cyclopoid species belonging to the genus Halicyclops, H. songsonensis sp. nov. is described from freshwater in Son river, Quang Binh province, Central Vietnam. The new species is distinguished from the other congeners species of the genus by a combination of the having 3:4:4:3 spine formula on P1-P4, lateral angular protuberances on the genital double-somite, a serrate hyaline frill of pre-anal somite little more developed than lateral and ventral parts, relatively long caudal rami, spiniform seta of proximalmost seta on P2-P3 Enp3 and showing the round/oval integumental window on cephalothorax and two next prosomites

    The COVID-19 global pandemic : a review of the Vietnamese Government response

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    The profound effect of COVID-19 pandemic has not eluded Vietnam, a lower-middle-income country that borders China, the country where the outbreak originated. Currently facing a second wave, Vietnam experienced several months of insignificant community-transmission, when the epidemic was effectively under control. This paper provides an account of the policies developed by the national COVID-19 response team during the first wave, from January to July 2020. Three key components were identified, including (i) the timely and decisive responses from the national and local authorities in the early phase of the pandemic, (ii) a society-wide approach, supported by an effective risk communication strategy which managed to gain the public trust, and (iii) an effective preventive medicine and infectious disease control system, residing in early case identification, strict isolation, effective contact tracing and compulsory quarantine of close contacts. While several other important components of the health system, such as financing and human resources remain largely under-explored, the results of this study show that a mixture of measures may lead to an effective epidemic management

    High Sound-contrast Inverse Scattering by MR-MF-DBIM Scheme

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    In ultrasound tomography, cross-sectional images represent the spatial distribution of the physical parameters of a target of interest, which can be obtained based on scattered ultrasound measurements. These measurements can be obtained from dense datasets collected at different transmitter and receiver locations, and using multiple frequencies. The Born approximation method, which provides a simple linear relationship between the objective function and the scattering field, has been adopted to resolve the inverse scattering problem. The distorted Born iterative method (DBIM), which utilizes the first-order Born approximation, is a productive diffraction tomography scheme. In this article, the range of interpolation applications is extended at the multilayer level, taking into account the advantages of integrating this multilayer level with multiple frequencies for the DBIM. Specifically, we consider: (a) a multi-resolution technique, i.e., a multi-step interpolation for the DBIM: MR-DBIM, with the advantage that the normalized absolute error is reduced by 18.67% and 37.21% in comparison with one-step interpolation DBIM and typical DBIM, respectively; (b) the integration of multi-resolution and multi-frequency techniques with the DBIM: MR-MF-DBIM, which is applied to image targets with high sound contrast in a strongly scattering medium. Relative to MR-DBIM, this integration offers a 44.01% reduction in the normalized absolute error

    Applying the Theory of Planned Behavior (TPB) in Investigating Consumption Behavior in Vietnam

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    This study explored the consumer behavior based on TPB model in Vietnam. The hypotheses are empirically tested using survey data obtained from consumer who purchased green products of household appliances in Hanoi– the capital of Vietnam. During the study, the research team added the “trend” variable which is a characteristic variable in Vietnam. The results of the multiple regression analysis show that attitude, subjective norm, perceived behavioral control, trend have significant and positive effect on household appliances product. The research findings are discussed and implications for government, manufacturing businesses, retail businesses to embrace green consumption behavior Keywords: Consumption Behavior; Vietnam; TPB; Household appliances DOI: 10.7176/EJBM/12-18-16 Publication date:June 30th 202

    Fed-LSAE: Thwarting Poisoning Attacks against Federated Cyber Threat Detection System via Autoencoder-based Latent Space Inspection

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    The significant rise of security concerns in conventional centralized learning has promoted federated learning (FL) adoption in building intelligent applications without privacy breaches. In cybersecurity, the sensitive data along with the contextual information and high-quality labeling in each enterprise organization play an essential role in constructing high-performance machine learning (ML) models for detecting cyber threats. Nonetheless, the risks coming from poisoning internal adversaries against FL systems have raised discussions about designing robust anti-poisoning frameworks. Whereas defensive mechanisms in the past were based on outlier detection, recent approaches tend to be more concerned with latent space representation. In this paper, we investigate a novel robust aggregation method for FL, namely Fed-LSAE, which takes advantage of latent space representation via the penultimate layer and Autoencoder to exclude malicious clients from the training process. The experimental results on the CIC-ToN-IoT and N-BaIoT datasets confirm the feasibility of our defensive mechanism against cutting-edge poisoning attacks for developing a robust FL-based threat detector in the context of IoT. More specifically, the FL evaluation witnesses an upward trend of approximately 98% across all metrics when integrating with our Fed-LSAE defense

    Arbitrary Form Plasmonic Structures: Optical Realization, Numerical Analysis and Demonstration Applications

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    Surface plasmon resonance has attracted more and more attention thanks to its wide range of applications in numerous fields (physics, chemistry, biology, etc.). In this chapter, we present different aspects, from theoretical calculation and experimental fabrication to applications demonstration, related to arbitrary shape plasmonic nanostructures. First, numerical calculations based on finite-difference time-domain method were realized to investigate the plasmonic properties of gold nanostructures having various size and shapes. Then the direct laser writing method was demonstrated as an excellent tool for fabrication on demand of arbitrary nanostructures. Plasmonic structures were obtained indirectly by a standard lift-off method from a polymeric template and directly by tightly focusing a continuous-wave laser beam onto a metallic thin film. Finally, demonstration of various applications of fabricated plasmonic structures, namely plasmonic-based data storage, color nanoprinter, tunable filters, and plasmonic-magneto-optics sensors will be shown

    DETERMINATION THE PRIORITY OF FACTORS INFLUENCING OVERSEAS INVESTMENT DESTINATIONS OF BUSINESSES USING AN ANALYTIC HIERARCHY PROCESS METHOD

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    Because of the great benefits overseas investment brings, countries and businesses are increasingly concerned with the question of an ideal investment destination. Many studies have shown that, factors of the consumption market, the infrastructure and resources, economic and political environment have a significant impact on the decision to choose an investment location, however the priority order of these factors are different for various research spaces. By studying the specific case of Viettel Group - one of the largest telecommunications groups in Vietnam that is having many international investment activities in recent years, the study has been verified the priority order of factors influencing the decision to choose an overseas investment location of this corporation. The research outcomes show that the group of factors that have the most influence on investment decisions is the group "Consumption market", more specifically, the sub-factor "Market Size" is considered more than the others.    Keywords: Investment Destinations, Foreign Investment Decision, Analytic Hierarchy Process

    Influence of Spray Rate on Structural and Optical Properties of Sprayed ZnO Films

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    In this report, the ZnO nanostructure films have been deposited by ultrasonic spray pyrolysis technique (USP) on fluorine doped tinoxide~(FTO) substrate using zinc acetate and aqueous 2-propanol as reactants. The effects of solution spray rate on structural, morphological and optical properties of ZnO nanostructure films were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and UV-Vis measurements. ZnO films were crystallized in the hexagonal wurtzite phase and preferential orientation changed with changing of spray rate. Grain size and roughness of films depended on spray rate. Increasing spray rate made the films grown with bigger grain size and higher roughness. Band gap energy was determined from the UV-Vis. Its value was found to be of 3.25 eV and was almost independent on the spray rate
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