610 research outputs found
Integrating self-managed work teams into Vietnamese SME organization: a case study at a food retail chain in Da Nang city, Vietnam
Purpose
Vietnam is having tough competition when joining free trade zones. SMEs in Vietnam with limited resources and a low level of management and advanced technology applications are facing hard time when competing with companies, especially multi-national companies. To respond to difficulties, many of Vietnamese companies try to implement SMWTs to boost the organizational performance and reduce waste. However, there are hidden barriers that prevent them from implementing effective SMWTs. This paper aims to figure out whether SMWTs can be successfully integrated and the barriers that prevent the transformation, so that the organizations can prepare well enough before the implementation.
Methodology
In-depth interview with team members at an SME in Vietnam, then compare the collected information to the literature synthesis to predict the effectiveness of the SMWT
Edge of Infinity: The Clash between Edge Effect and Infinity Assumption for the Distribution of Charge on a Conducting Plate
We re-examine a familiar problem given in introductory physics courses, about
determining the induced charge distribution on an uncharged
``infinitely-large'' conducting plate when placing parallel to it a uniform
charged dielectric plate of the same size. We show that, no matter how large
the plates are, the edge effect will always be strong enough to influence the
charge distribution deep in the central region, which totally destroyed the
infinity assumption (that the surface charge densities on the two sides are
uniform and of opposite magnitudes). For a more detailed analysis, we solve
Poisson's equation for a similar setting in two-dimensional space and obtain
the exact charge distribution, helping us to understand what happens how charge
distributes at the central, the asymptotic, and the edge regions
Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems
It is well-known that the traditional transmit beamforming at a base station
(BS) to manage interference in serving multiple users is effective only when
the number of users is less than the number of transmit antennas at the BS.
Non-orthogonal multiple access (NOMA) can improve the throughput of users with
poorer channel conditions by compromising their own privacy because other users
with better channel conditions can decode the information of users in poorer
channel state. NOMA still prefers that the number of users is less than the
number of antennas at the BS transmitter. This paper resolves such issues by
allocating separate fractional time slots for serving the users with similar
channel conditions. This enables the BS to serve more users within the time
unit while the privacy of each user is preserved. The fractional times and
beamforming vectors are jointly optimized to maximize the system's throughput.
An efficient path-following algorithm, which invokes a simple convex quadratic
program at each iteration, is proposed for the solution of this challenging
optimization problem. Numerical results confirm its versatility.Comment: IEEE Communications Letters (To Appear
The Effect of Charge Discretization on the Electrical Field inside a Conductor
We show how the electrical field inside the conductor changes as a function
of the number of charged-particles. We show that the non-vanishing electrical
field is concentrated near the surface of the conductor, at a shallow depth on
the same order of magnitude as the separation between charges. Our study has
illustrated the effect of charge discretization on a fundamental emergent law
of electrostatics
Static and vibration analysis of isotropic and functionally graded sandwich plates using an edge-based MITC3 finite elements
Static and vibration analysis of isotropic and functionally graded sandwich plates using a higher-order shear deformation theory is presented in this paper. Lagrangian functional is used to derive the equations of motion. The mixed interpolation of tensorial components (MITC) approach and edge-based-strain technique is used to solve problems. A MITC3 three-node triangle element with 7 degree-of-freedoms per nodes that only requires the C0-type continuity is developed. Numerical results for isotropic and functionally graded sandwich plates with different boundary conditions are proposed to validate the developed theory and to investigate effects of material distribution, side-to-thickness ratio, thickness ratio of layers and boundary conditions on the deflection, stresses and natural frequencies of the plates
Voltage Stability Monitoring based on Adaptive Dynamic Mode Decomposition
This paper develops a new voltage stability monitoring method using dynamic mode decomposition (DMD) and its adaptive variance. First, state estimation (SE) is used to estimate the voltage in the system. Then, the measured voltages from the phasor measurement units (PMU) and estimations from SE are used as the inputs for DMD to predict the long-term voltage dynamic. Furthermore, to improve the prediction performance, the normal DMD is improved by adaptively changing the size of input samples based on the error in the training phase, named adaptive DMD (ADMD). The effectiveness of the proposed method is validated on the Nordic32 test system, which is recommended as the test system for voltage stability studies. Different contingency scenarios are used, and the results show that the proposed method is able to monitor the voltage stability after a disturbance (i.e., 4.3x10-4 MAPE for a stable case and 0.0041 MAPE for an unstable case). Furthermore, the results from a scenario in which a real-world oscillation event is used show high accuracy in voltage stability monitoring of the proposed ADMD method
Improving the Performance of Lithium Ion Batteries at Low Temperature
The ability for Li-ion batteries to operate at low temperatures is extremely critical for the development of energy storage for electric and hybrid electric vehicle technologies. Currently, Li-ion cells have limited success in operating at temperature below –10 deg C. Electrolyte conductivity at low temperature is not the main cause of the poor performance of Li-ion cells. Rather the formation of a tight interfacial film between the electrolyte and the electrodes has often been an issue that resulted in a progressive capacity fading and limited discharge rate capability. The objective of our Phase I work is to develop novel electrolytes that can form low interfacial resistance solid electrolyte interface (SEI) films on carbon anodes and metal oxide cathodes. From the results of our Phase I work, we found that the interfacial impedance of Fluoro Ethylene Carbonate (FEC) electrolyte at the low temperature of –20degC is astonishingly low, compared to the baseline 1.2M LiPFEMC:EC:PC:DMC (10:20:10:60) electrolyte. We found that electrolyte formulations with fluorinated carbonate co-solvent have excellent film forming properties and better de-solvation characteristics to decrease the interfacial SEI film resistance and facilitate the Li-ion diffusion across the SEI film. The very overwhelming low interfacial impedance for FEC electrolytes will translate into Li-ion cells with much higher power for cold cranking and high Regen/charge at the low temperature. Further, since the SEI film resistance is low, Li interaction kinetics into the electrode will remain very fast and thus Li plating during Regen/charge period be will less likely to happen
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