Firm exporting and employee benefits: first evidence from Vietnam manufacturing SMEs

This study examines linkages between the export participation of firms and employee benefits in terms of wages and employment quality. Based on a uniquely matched firmworker panel dataset for 2007 and 2009, we find evidence that export participation by firms in Vietnam has a positive impact on wages when taking into account firm characteristics alone. However, the exporter wage premium falls when both firm and worker characteristics are controlled for, and it decreases further when controlling for time-invariant unobservable factors by spell fixed effect estimation. While there are many studies on the export wage premium, the role of export participation on the quality of employment remains largely unexplored. By using a firm-level balanced panel dataset for the same period, our results suggest that export participation has a negative effect on employment quality. Nevertheless, the impact of export participation on both wages and employment quality vary greatly with respect to levels of technology

Buckling and postbuckling of CNT-reinforced composite sandwich cylindrical panels subjected to axial compression in thermal environments

An analytical investigation on the buckling and postbuckling behavior of carbon nanotube reinforced composite (CNTRC) sandwich cylindrical panels exposed to thermal environments and subjected to uniform axial compression is presented in this paper. Beside sandwich model with CNTRC face sheets in the literature, the present work suggests a sandwich model with CNTRC core layer and homogeneous face sheets. Carbon nanotubes (CNTs) are reinforced into matrix phase through uniform or functionally graded distributions. Effective properties of nanocomposite layers are determined according to extended rule of mixture. Formulations are based on the first order shear deformation theory taking into account Von Karman-Donnell nonlinearity. Approximate solutions are assumed to satisfy simply supported boundary conditions and Galerkin method is used to derive the closed-form expression of nonlinear load-deflection relation from which buckling loads and postbuckling paths are determined. Numerical examples are carried out and interesting remarks are given

Role of Scientific Research for Lecturers of Current Universities

Scientific research for university lecturers plays an important role in training creative thinking ability, research capacity and scientific working style  for researchers. This contributes to clarifying some scientific issues and solving practical problems that arise in order to improve the quality of teaching. This article focuses on analyzing some issues about the role of scientific research for university lecturers today

Double-Side Electromagnetic Band Gap Structure for Improving Dual-Band MIMO Antenna Performance

A double-side EBG structure with equivalent circuit model is proposed in this paper. Making H shape on surface and H with bridge shape on ground, the novel EBG that is built on FR4 substrate with height of 1.6mm, gets compact size of 8.6x8.6 mm2 at 2.6 GHz resonant frequency. Using 1x7 EBG structures for dual-band MIMO system, several performance parameters of antenna are improved. Firstly, the mutual coupling between antenna elements gets -40dB in the lower band and -30dB in the higher one with narrow distance of 0.11l from feeding point to feeding point. Then, at 2.6GHz, the antenna gain is increased significant by 160% as well as radiation efficiency of antenna is better. This improvement is unable to get in previous EBG studie

Characterization of pig farms in Hung Yen, Hai Duong and Bac Ninh provinces

peer reviewedIn order to characterization of pig farms in the Red River Delta, a study was conducted on 90 pig farms in Hung Yen, Hai Duong and Bac Ninh provinces from June to December 2006. Results show that most of the pig farms had been built for five years with a small size (0.5 hectare per farm). The invested capital was about 300-400 millions VND per farm. Four main sow groups used in the farms included crossbred exotic sows (51.1%), crossbred sow between local and exotic breeds (14.4%), purebred Landrace and Yorkshire breeds (15.6 and 18.9%, respectively). The boars were various (Duroc 30%, Yorkshire 21%, Landrace 13%, PiÐtrain × Duroc 36% and others). The pigs farms were faced with several difficulties such as limited land, lack of invested capital, uncontrolled quality of breeding pigs, high costs of feed, poor hygiene condition and diseases

Prediction of shoreline changes in Almanarre beach using geospatial techniques

207-217In this study, the remote sensing and Geographic Information System (GIS) techniques coupled with the Digital Shoreline Analysis System (DSAS) is applied to detect the historical shoreline changes as well as to predict the future shoreline position along Almanarre beach which is being threatened by severe erosion. The results show that Almanarre beach suffered erosion with an average annual change rate of about -0.24 m/year over the period of 1973-2015. The most severe erosion was observed near Landmark B17 with the maximum erosion rate of -0.86 m/year. Moreover, the shoreline change in 2020 and 2050 are predicted at approximately -0.05 m/year and -0.22 m/year, respectively. The areas around Landmarks B06-08 and Landmarks B16-18 will be eroded with the maximum recession rates of -0.89 m/year and -0.94 m/year, respectively. This research proves that the combination of geospatial techniques and numerical model can be a reliable approach for investigating the shoreline change trend

LPV force observer design and experimental validation from a dynamical semi-active ER damper model

International audienceThis paper presents an LPV damping force observer of ElectroRheological (ER) dampers for a real automotive suspension system, taking the dynamic characteristic of damper into account. First, an extended nonlinear quarter-car model is considered, where the time constant representing the damper dynamics is varying according to the control level. This is rewritten as an LPV model which is used to design an LPV observer. The objective of the LPV observer is to minimize the effects of bounded unknown input disturbances (unknown road profile and measurement noises) on the state estimation errors through an H ∞ criterion, while the damper nonlinearity is bounded using a Lipschitz condition. Two low-cost accelerometers (the sprung mass and the unsprung mass accelerations) are used as inputs for the proposed methodology only. To experimentally assess the proposed approach, it is implemented on the 1/5-scaled real vehicle-INOVE testbench of GIPSA-lab. This shows the ability of the observer to estimate the damper force in real-time, face to unknown inputs disturbance and sensor noises

A Robust Mobile Robot Navigation System using Neuro-Fuzzy Kalman Filtering and Optimal Fusion of Behavior-based Fuzzy Controllers

This study proposes a control system model for mobile robots navigating in unknown environments. The proposed model includes a neuro-fuzzy Extended Kalman Filter for localization task and a behaviorbased fuzzy multi-controller navigation module. The neuro-fuzzy EKF, used for estimating the robot’s position from sensor readings, is an enhanced EKF whose noise covariance matrix is progressively adjusted by a fuzzy neural network. The navigation module features a series of independently-executed fuzzy controllers, each deals with a specific navigation sub-task, or behavior, and a multi-objective optimizer to coordinate all behaviors. The membership functions of all fuzzy controllers play the roles of objective functions for the optimizer, which produces an overall Pareto-optimal control signal to drive the robot. A number of simulations and real-world experiments were conducted to evaluate the performance of this model