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Objectives: Workplace productivity has always been affected by a high-stress level and lack of sports activities. This aspect requires the researchers' emphasis and the present research performs this role by examining the much neglected impact of sports activities, stress management, and work-life balance on workplace productivity of manufacturing firms in Vietnam. The study also investigated the mediating impact of stress management and work-life balance among sports activities and workplace productivity of manufacturing firms in Vietnam. Methods: The primary data was collected through survey questionnaires from the employees of manufacturing companies in Vietnam. The research also applied the PLS-SEM using Smart-PLS to check the reliability and association among variables. Results: The outcomes indicated that sports activities, stress management, and work-life balance have a positive linkage with the workplace productivity of manufacturing firms in Vietnam. The outcomes also revealed that stress management and work-life balance significantly mediate among sports activities and workplace productivity of manufacturing firms in Vietnam. Conclusion: This research guides the policymakers in making policies related to workplace productivity improvement using sports activities, work-life balance, and stress management.

In this paper, we present a method for realizing all-optical Discrete Sine and Cosine Transform (DST/DCT) for image compression. We show that all-optical DST and DCT can be achieved by using only one 4x4 MMI (multimode interference) coupler at a suitable width and length. The proposed method can process image data at high speed and high bandwidth. We use numerical methods for simulating the whole devices

We present a new architecture for generation of multilevel pulse amplitude modulation (PAM-4) signal generation based on cascaded 4x4 multimode interference (MMI) structure used for optical interconnects and data centre network. The proposed device can generate two ring resonator structures with capability of critical coupling control. The push-pull configuration then is used at two ring resonators for PAM-4 level generation, so a zero chirp can be achieved. In this structure an M-shape transmission can be created for the first time. We use this property for an extreme reduction of power consumption with a lower level than 4-28 times compared with the PAM-4 generation based on the Mach Zehnder Modulator (MZM), respectively. Based on this structure, an extreme high bandwidth and compact footprint are also achieved. The whole device is designed and analyzed using the existing VLSI silicon photonics.

We present a new method for image compression in all-optical domain. The new hardware architecture is suitable for directly integrating with digital cameras for image processing. The proposed architecture is based on the optical Haar wavelet transform (HWT) using only one 4x4 multimode interference (MMI) coupler cascaded with a 2x2 MMI coupler. The processing of images therefore is at very high speed.

Over several decades, the Vietnamese government has increasingly cut its investment in the public higher education system and has also introduced a cost-sharing mechanism. Under this scheme, Vietnamese public universities have been seeking other sources of revenue. Despite the bold emphasis on the need for revenue diversification in higher education in Vietnam, there is little empirical evidence of the status quo of Vietnamese public higher education finance. The purpose of this paper was to fill this research gap by using the Hirschman–Herfindahl Index to estimate the degree of financial diversity in 51 public universities in Vietnam between 2015 and 2017. Our findings revealed that all institutions in this study were unsustainable due to their weak financial diversity. Suggestions for policy makers and university leaders that may enhance financial sustainability include the adoption of performance-based financial allocations and the implementation of capacity-building programs for universities with regard to fund-raising and entrepreneurship skills.

PurposeThis study aims to integrate predictions from clinical psychology and UPPS impulsivity with the theory of planned behaviors (TPB) to draw a conceptual framework and test the prediction that attention deficit hyperactivity disorder (ADHD) symptoms, impulsivity would contribute to the prediction of the reasoned cognitive process of entrepreneurship over and above key predictors from an extended TPB model.Design/methodology/approachThis study utilized a sample of 2,482 students from 14 universities/institutes in Vietnam; confirmatory factor analysis was employed to test the validity and reliability. Then, regression analysis with PROCESS macro approach (5,000 bootstrap sample and 95% confidence interval) was employed to estimate the association paths and multiple mediators.FindingsThe study reveals that ADHD symptoms and impulsivity substantially contribute to the exploration of an entrepreneurial intention throughout TPB predictors, with those higher in ADHD symptoms and impulsivity having higher intentions to engage in business venturing. Moreover, UPPS impulsiveness might valuably be incorporated with TPB predictors while predicting behaviors that are often examined as the process of rational cognitive strategies business venturing.Practical implicationsThis study showed that a start-up business can be seen as a career choice for students who exhibit extensive ADHD symptoms to use their talents effectively, thus contributing to creating value for society and improving personal well-being.Originality/valueThis article stood to make contributions to entrepreneurship literature by investigating the effects of ADHD symptoms, four impulsivity traits on an entrepreneurial intention via three precursors in TPB, including attitude toward entrepreneurship, subjective norms and perceived behavioral control.

Trung Thanh Le,1 Ba Phong Le2 1National Economics University, Hanoi, Vietnam; 2Hanoi University of Industry, Hanoi, VietnamCorrespondence: Ba Phong Le Email lebaphong@haui.edu.vnBackground: Improving organizational performance for firms in developing countries like Vietnam by huge investments in technological innovation is not feasible, because the majority of firms in these nations are small and medium size, with a lack of capital, resources, and R&D capabilities. Given the important role of change capability for organizational performance, the purpose of this paper is to investigate the impacts of transformational leadership (TL) on organizational performance via the mediating role of organizational change capability in cases of Vietnamese enterprise.Methods: Based on the cross-sectional design method and empirical data, this study applied analysis of moment structures (AMOS) and structural equation modeling (SEM) to inspect the link between the latent variables in the proposal research model through the empirical data gathered from 302 participators in 125 Vietnamese firms.Results: The findings of this study show the significant and positive influences of TL on organizational change capability and organizational performance. Importantly, organizational change capability significantly mediates the influence of TL on operational and financial performance.Conclusion: This study contributes to filling the gaps in the literature and advancing the insights of how TL fosters specific aspects of change capability for improving two crucial components of organizational performance, namely operational and financial performance.Keywords: transformational leadership, organizational performance, innovative culture, capable champions, operation performance, financial performance

This study reviews research related to the relationship between corporate culture and performance. From previous studies, the author proposes research gaps that need to be carried out in the future, in the context of Vietnamese textile and garment enterprises.

We present a new configuration based on multimode interference with a microring resonator feedback waveguide. The proposed configuration can create a deep Fano shape and provide a high sensitive sensor structure. In this paper, we is applied to seawater salinity sensor with a high sensitivity. We also propose an approach for these optical sensors integated with wireless sensor networks for online and real-time applications. The sensor structure can provide a sensitivity of 581nm/RIU based on wavelength shift based mechanism. We use silicon waveguides for the whole sensor designs and working at operating wavelength of 1550nm.

We propose a new structure for generating a Fano shape. This structure can be applied to design an optical sensor with a high sensitivity based on intensity mechanism using a 2×4 multimode interference (MMI) coupler. The sensor structure can provide a very sensitivity (higher than 10 times) compared with the traditional structure based on Mach Zehnder interferometer (MZI) and microring resonators (MRR). For CMOS compatibility, we use silicon on insluator (SOI) waveguide for the whole sensor designs. The sensing structure can work at operating wavelength of 1550nm, that is suitable for fiber-optic communication and real-time measurement applications.

Sustainable development practices have become very important for firms to go beyond short-term profitability, towards economic, environmental and social sustainability. This research aims to examine the relationship between a firm&rsquo, s sustainable development practices and its financial performance. Modelled as a multidimensional construct, sustainable development practices are represented by environmental practices, social practices in the workplace and social practices in the community, while financial performance is determined by profitability and growth. Using a mixed method survey, data were obtained from 389 textile firms in Vietnam, where there is a dire need to promote sustainable and environmental practices. Data analysis using partial least squares structural equation modeling demonstrates that sustainable development practices positively affect financial performance directly and indirectly via customer loyalty, employee satisfaction and corporate reputation. The findings also reveal the moderating role of entrepreneurial orientation, whereby the impact of sustainable development practices on financial performance is stronger for firms that are more innovative, proactive and willing to take risks. Taken together, these findings provide support for firms to holistically implement sustainable development practices and adopt an entrepreneurial orientation.

We propose a new kind of microring resonators (MRR) based on 4 × 4 multimode interference (MMI) couplers for multichannel and highly sensitive chemical and biological sensors. The proposed sensor structure has advantages of compactness and high sensitivity compared with the reported sensing structures. By using the transfer matrix method (TMM) and numerical simulations, the designs of the sensor based on silicon waveguides are optimized and demonstrated in detail. We apply our structure to detect glucose and ethanol concentrations simultaneously. A high sensitivity of 9000 nm/RIU, detection limit of 2 × 10‒4 for glucose sensing and sensitivity of 6000 nm/RIU, detection limit of 1.3 × 10‒5 for ethanol sensing are achieved.

A high bandwidth all-optical 3×3 switch based on general interference multimode interference (GI-MMI) structure is proposed in this study. Two 3×3 multimode interference couplers are cascaded to realize an all-optical switch operating at both wavelengths of 1550 nm and 1310 nm. Two nonlinear directional couplers at two outer-arms of the structure are used as all-optical phase shifters to achieve all switching states and to control the switching states. Analytical expressions for switching operation using the transfer matrix method are presented. The beam propagation method (BPM) is used to design and optimize the whole structure. The optimal design of the all-optical phase shifters and 3×3 MMI couplers are carried out to reduce the switching power and loss.

A cascaded microring resonator based on silicon waveguides with an MMI (Multimode Interference) based Sagnac reflector is proposed in this study. By controlling the coupling coefficients with the used of the MMI based Sagnac reflector, the double of both pulse delay and advancement for the slow and fast light can be achieved. The new structure can produce the fast and slow light phenomenon on one chip with a double of the time delay and pulse advancement. By using the Sagnac reflector, the device is very compact. Transfer matrix method and FDTD (Finite Difference Time Domain) simulation are used to obtain the characteristics of the device. The transmission, phase, group delay and pulse propagation are analyzed in detail. Our FDTD simulations show a good agreement with the analytical theory.

Ultra High Performance Concrete (UHPC) is a new class of concrete that has been developed in recent decades for its exceptional properties of strength and durability. The production of UHPC normally requires the use of large amounts of cement that results in the unsustainable development of this concrete system. Therefore, the study of the use of mineral admixtures will be a good solution to reduce cement consumption while improving the properties of the UHPC is of great practical significance in terms of sustainable construction development. The objective of this study is to use a high volume of fly ash to replace cement for the production of UHPC under both standard- and heat treatment- curing conditions. The results show that it is possible to use fly ash up to 40 and 50% by mass of binder under standard curing conditions and heat treatment conditions, respectively, to make the UHPC with the 28d-compressive strength of over 120 MPa. It means that up to 60% of binder (10% silica fume and 50% fly ash) can be used to produce the low cement ultra high performance concrete.

All-optical logic gates have attracted considerable attention over the past decade. They have found application as adders, subtractors, header recognizers, parity checkers and in encryption systems. In this paper, we present a new structure based on cascaded 4×4 and 2×2 multimode interference (MMI) couplers for implementing optical XOR, XNOR, NAND and OR logic gates. The emphasis of the design is on optimising bandwidth and fabrication tolerance. Such a design would be useful for optical label swapping and recognition in optical packet switching networks. We use silicon on insulator (SOI) waveguides that are compatible with the CMOS technology, for designing the whole device. The Beam Propagation Method (BPM) and the Eigenmode Expansion Method (EEM) are used for numerical simulations. We show that the contrast ratios for logic 1 and logic 0 for XOR, XNOR, NAND, and OR gates are from 18 dB to 28 dB for a bandwidth of 30nm, respectively. A large fabrication tolerance of ±500 nm can be achieved by using this structure.

We propose a novel optical integrated structure using only one 4×4 multimode interference (MMI) coupler with support of two microring resonators for glucose sensor. Due to the presence of the analyte, the wavelength shift of the output spectrum is realized. Our structure can provide a high sensitivity, low detection limit and good figure of merit (FoM).

A new microring resonators (MRR) based on 4×4 multimode interference (MMI) couplers for multichannel and highly sensitive chemical and biological sensors is proposed in this paper. The proposed sensor structure has advantages of compactness, high sensitivity compared with the reported sensing structures. By using the transfer matrix method (TMM) and numerical simulations, the designs of the sensor based on silicon nanowires are optimized and demonstrated in detail. The glucose and ethanol sensing by using our structure is investigated.

Multimode interference in optical waveguide is attractive for optical signal processing in recent years. In this paper, we propose and design a 3 × 3 all-optical switch using 3 × 3 General Interference Multimode Interference (GI-MMI) structures. Nonlinear directional couplers based on the Kerr effect in two arms of the structure are used as phase shifters. We use chalcogenide glass on silica platform for designing the device structure. The switching states of the device can be controlled by adjusting the optical control signals at the phase shifters in the two arms. The transfer matrix method (TMM) and beam propagation method (BPM) are used for designing and optimizing the device structure.

We propose a novel microring resonator coupled 4×4 generalized Mach Zehnder interferometer (GMZI) structure to produce Fano resonance line shapes. The structure can produce two independent Fano resonance line shapes. Two phase shifters are introduced in two arms of the 4×4 GMZI to control the variation of the Fano line shapes. The other aim of this study is to use silicon waveguides, that are compatible with the existing CMOS (Complementary Metal-Oxide-Semiconductor) fabrication technology, for designing the proposed devices. The transfer matrix method (TMM) and beam propagation method (BPM) are used for analytical analysis and first order design of the device. Finally, we discuss potential applications of the new device for sensing, all-optical switching applications and generation of electromagnetically induced transparency (EIT) effect.

We show that it is possible to obtain 2 × 2 couplers based on multimode interference (MMI) structures with nineteen new power-splitting ratios by cascading three or four MMI couplers. The other aim of this study is to use silicon waveguides, that are compatible with the existing CMOS (Complementary Metal-Oxide-Semiconductor) fabrication technology, for designing the proposed devices. The proposed MMI couplers with new power splitting ratios have simple geometries and low losses. These MMI couplers can offer valuable new possibilities for designing MMI waveguide-based photonic integrated circuits such as all-optical interconnects, microring resonators, clock distribution, Mach Zehnder Interferometer based on MMI couplers and other all-optical processing applications. The transfer matrix method (TMM) and modified effective index method (MEIM) along with the support of the 3D Beam Propagation Method (3D BPM) are used to optimize the proposed devices.

This paper presents a new design for an insensitive-polarization all-optical switch using 2 × 2 multimode interference (MMI) couplers. The switching structure can operate at central operating wavelength 1550 nm for both polarizations. A nonlinear directional coupler is used to realize the phase shifter and therefore switching mechanism is obtained. The transfer matrix method and beam propagation method are used to design and optimize the whole device structure.