Smartphone indoor positioning based on enhanced BLE beacon multi-lateration

In this paper, we introduce a smartphone indoor positioning method using bluetooth low energy (BLE) beacon multilateration. At first, based on signal strength analysis, we construct a distance calculation model for BLE beacons. Then, with the aims to improve positioning accuracy, we propose an improved lateral method (range-based method) which is applied for 4 nearby beacons. The method is intended to design a real-time system for some services such as emergency assistance, personal localization and tracking, location-based advertising and marketing, etc. Experimental results show that the proposed method achieves high accuracy when compared with the state of the art lateral methods such as geometry-based (conventional trilateration), least square estimation-based (LSE-based) and weighted LSE-based

iBeacon-based indoor positioning system: from theory to practical deployment

Developing an indoor positioning system became essential when global positioning system signals could not work well in indoor environments. Mobile positioning can be accomplished via many radio frequency technology such as Bluetooth low energy (BLE), wireless fidelity (Wi-Fi), ultra-wideband (UWB), and so on. With the pressing need for indoor positioning systems, we, in this work, present a deployment scheme for smartphone using Bluetooth iBeacons. Three main parts, hardware deployment, software deployment, and positioning accuracy assessment, are discussed carefully to find the optimal solution for a complete indoor positioning system. Our application and experimental results show that proposed solution is feasible and indoor positioning system is completely attainable

Factors affecting farmers' decisions to participate in agricultural tourism activities: a case study in the Mekong Delta, Vietnam

Agricultural tourism, or agritourism, creates jobs for household members, diversifies farming activities and sources of revenue, and lowers the household's reliance on nature. This study uses Binary Logistic regression analysis to conduct a direct survey of 450 agricultural households in the Mekong Delta, Vietnam. The findings indicate that influencing factors include the following: support for local government policies; membership in farmer associations, unions, and extension clubs; awareness of the benefits of agritourism; a variety of production models; Internet access; education level; and membership in tourism associations, travel organisations. Distance between farms and agritourism destinations.Ho Phi Dinh (Phan Thiet University), Phuoc Huu Vo (Academy of Politics Region II), Duong Ngoc Pham (University of Finance and Marketing), Thanh Quang Ngo (School of Government, University of Economics)Includes bibliographical references

Catalytic Dye Oxidation over CeO2 Nanoparticles Supported on Regenerated Cellulose Membrane

A novel regenerated cellulose (RC) membrane containing cerium oxide (CeO2) nanoparticles is described in detail. In this work, CeO2 nanoparticles with high surface area and mesoporosity were prepared by a modified template-assisted precipitation method. Successful synthesis was achieved using cerium nitrate as a precursor, adjusting the final pH solution to around 11 by ammonium hydroxide and ethylene diamine, and annealing at 550 °C for 3 hours under a protective gas flow. This resulted in a surface area of 55.55 m².g–1 for the nanoparticles. The regenerated cellulose membrane containing CeO2 particles was synthesized by the novel and environmentally friendly method. The catalyst CeO2 and cellulose/CeO2 membrane were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), and Brunauer-Emmett-Teller (BET) measurements. The g-value of 2.276 has confirmed the presence of the surface superoxide species of CeO2 nanoparticles in EPR. The photocatalytic activity of the catalyst and the membrane containing the catalyst was evaluated through the degradation of methylene blue under visible light irradiation by UV-VIS measurements. The cellulose/CeO2 membrane degraded 80% of the methylene blue solution in 120 minutes, showing a better photocatalytic activity than the CeO2 catalyst, which degraded approximately 62% in the same period. It has been proven that the RC membrane is not only a good transparent supporting material but also a good adsorption for high-performance of CeO2 catalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Educating and training labor force Under Covid 19; Impacts to Meet Market Demand in Vietnam during Globalization and Integration Era

During integration and globalization era, Vietnam labor market face challenges but also have lots of opportunities. This paper mainly use qualitative analysis with statistics, synthesis and inductive methods, combine with dialectical materialism methods. Research results indicate that because many Vietnam laborers do not have enough work skills and lack of training programs, they meet difficulties on job; hence, human resource management need to deal with issues of improving skills and knowledge for workforce to meet demand under EVFTA and Industry 4.0. There are lots of job opportunities from banking, finance to manufacturing, industries. Last but not least, this study also propose some solutions to deal with challenges in Human resources to meet demand from corporations. For instance, we need to invest more on equipment and infrastructures, as well as quality of trainers for human resources of training schools, so that Vietnam businesses can overcome challenges from EVFTA

The Relationship between Foreign Direct Investment, Electricity Consumption and Economic Growth in Vietnam

One of the prerequisites for the successful implementation of national industrialization and modernization is the synchronous development of fundamental industries. Electricity is a key industry that determines the success of other industries. The main purpose of this paper is to investigate the causal relationship between electricity consumption, foreign direct investment and economic growth in Vietnam during the period 1990-2015, by using Toda-Yamamoto approach and autoregressive distributed lag (ARDL) approach. The empirical results show strong statistical evidence that electricity consumption and foreign direct investment have positive impacts on economic growth in Vietnam in both short term and long term. Keywords: FDI, electricity consumption, economic growth, Vietnam. JEL Classifications: F21; F43; Q4

Spondylolysis-induced Multilevel Lumbar Spondylolisthesis; Challenges in Lumbar Spine Surgery

Lumbar spondylolysis and multilevel lumbar spondylolysis account for 4.4-5.8% and 0.3% of the general population, and multilevel lumbar spondylolysis resulting in spondylolisthesis is even rarer. Herein, we report two cases of three-level lumbar spondylolisthesis because of spondylolysis: A 49-year-old woman was admitted to the hospital for dull lower back pain over the past 8 months, with exacerbating symptoms when standing and walking. Spasticity at lumbar region and radiculopathy at S1 nerve root was found on examination and a 63-year-old man was admitted to the hospital because of numbness and perianal sensory disturbances with difficulty urinating 2 weeks ago, the symptoms gradually increased to the time of examination. Both patients were diagnosed with multilevel lumbar spondylolisthesis because of spondylolysis and were indicated for posterior lumbar interbody fusion (PLIF). After surgery, both patients recovered well without any significant complications. The improved treatment results suggest the application of PLIF technique to treat spondylolysis-induced multilevel lumbar spondylolisthesis

Organic - Inorganic Hybrid Luminescent Composite for Solid-state Lighting

White light emitting diodes (WLEDs) made by coating organic and inorganic hybrid composites on blue LED chips. Y3Al5O12:Ce (YAG:Ce) nano inorganic powder prepared by low-temperature Sol-Gel method exhibited broad green emission with the peak at 521 nm. Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) polymer has high luminescence efficiency and red emission peak at 590 nm. The white light was obtained by mixing blue light from emission of the blue LED chip - Indium Gallium Nitride (InGaN) and green-red light from the fluorescence of nano- YAG:Ce and MEH-PPV polymer hybrid composite. The hybrid nanocomposite-based WLEDs exhibited broad band emission spectra from blue light to red wavelengths and provided the white light with a CIE-1931 coordinate of x = 0.2986, y = 0.2620 and a colour rendering index Ra = 84.36. The results suggest a potential application of nanocomposite based WLEDs in efficient solid-state lighting

Preparation and Inverstigation of MEH-PPV Films Used for White Light Emitting Diodes

With the aim to prepare white Light Emitting Diode (WLED), the conjugate polymer films like (Poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were investigated. Spectroscopic (absorption and emission) spectra of the MEH-PPV films showed that this polymer is suitable for casting onto the chips of the blue InGaN LED to make WLED. The luminous flux measured on the WLEDs in the integrating sphere proved that the white light emission can be obtained from the combination of inorganic LED and conjugate (MEH-PPV) polymers with an optimal thickness and a high quality. The aging process of MEH-PPV films was found to be strongly dependent post-treatment conditions. Reasonable heat treatment condition for the MEH-PPV polymers was suggested as in vacuum of 5×10-2 Pa at a temperature of 120°C in, for 2 hous