Innovative Firm Performance Management Using a Recommendation System Based on Fuzzy Association Rules: The Case of Vietnam’s Apparel Small and Medium Enterprises

Purpose: This study aims to apply a classification algorithm based-on fuzzy association rules (FARs) to improve the effectiveness of firms' performance prediction problem. Particularly, this study investigates potential FARs exists between inputs and outputs of firms' performance management process. These extracted FARs could be used to help firm’s managers make better dicision to improve firm’s performance.   Theoretical framework: Private enterprise development has been identified as key to Vietnam's economy that was commonly depended on state enterprise. For that, understanding and improving firms' performance and productivity is one of the most important tasks, from both macro and micro perspectives. There have been many studies on Vietnam's firm performance, but mostly relying on econometric methods that limit the understanding with structural equations. This study, instead, attempts to utilize new achievements of Artificial Intelligence (AI) for this task. Among AI techniques, fuzzy association rule is able to address the relationship between input factors and firm performance indicators. For each company, the finding FARs can be used to predict its performance and then change the business plan or react to improve weekness of organization.   Design/Methodology/Approach: The proposal model is applied on data of small and medium-sized enterprises (SMEs) of the apparel industry in Vietnam in the period 2010-2015. The sample consist of a total of 23637 observation of  Vietnam firms in apparel and textile industry and contains 16 main criterias for those firms.   Finding: A recommendation system (RS) is constructed from disclosed FARs and is a key factor in a novel innovative firms' performance management process. The percentage of classified instances using the mining FARs is not quite high (about 82%), but it is not always the case. Vietnam’s apparel dataset includes rare classes of ROA, therefore applying only frequent FARs is not enough. This issue can be fixed by using both frequent and infrequent FARs.       Research, practical & social implications: The proposed model has a great opportunity to use not only in the small and medium-sized enterprises (SMEs) of the apparel industry but other industrial sectors. FARs support the well-understand of firm performance to firm’s manager and help them better to react. Besides, FARs could be used to create RSs that makes alerts about risk automatically.   Originality/Value: The fact, our current study is the first to inspect the ability of FARs on SMEs of the apparel industry in Vietnam. This study provides theoritical potential knowledge and empirical evidence in the application of FARs technology in innovative firm’s management

Model predictive direct power control of three-level T-type inverter-fed doubly-fed induction generator for wind energy system

The paper proposes a simplified direct power control strategy of a doubly-fed induction generator fed by a three-level T-type inverter based on finite control set model predictive control. A mathematical model based on grid voltage orientation was employed to determine the predictive values of the stator flux, rotor current, and capacitor voltages for all feasible rotor-side inverter output voltages. The active and reactive powers were calculated by using the grid voltage and the rotor current. A cost function was applied to track the active and reactive powers, maintain the balance of capacitor voltages, and reduce the common-mode voltage. The best switching control input was chosen by minimizing the cost function and implemented to the inverter. Different operating conditions of wind turbine systems were studied with Matlab/Simulink environment. The simulation results validate the improved performance of the proposed method compared with the classical control in terms of transient response and steady-state conditions

Iron-induced acceptor centers in the gallium nitride high electron mobility transistor: thermal simulation and analysis

The effect of the presence of iron-induced acceptor centers in the gallium nitride high electron mobility transistor is studied using device physics simulations at elevated temperatures (up to 600 K), as a lattice heat flow equation is solved self-consistently with the Poisson and the continuity equations to account for self-heating effects. It is shown that the acceptor centers intentionally introduced in the buffer layer of the device cause a shift of the input characteristics in the positive direction

Factors Affect Students’ Satisfaction In Blended Learning Courses In A Private University In Vietnam

Blended learning, a combination of online and offline learning, is believed to enhance students’ self-learning, and help increase their learning performances. To successfully operate a blended learning system, increasing the learners’ satisfaction seems to be an important task. Moreover, there should be a duty to understand the self-efficacy of a student to encourage them to participate in this course (Chen & Yao, 2016). As a result, knowing the internal or external factors that influence student satisfaction in blended learning is critical for the effective design of blended learning courses in the future (Graham, Henrie, & Gibbons, 2013). In this study, a 76-item survey questionnaire with a five-level Likert scale was administered to 2403 students, in which 453 returned but just 345 responses were qualified for data analysis. The questionnaire was adapted from the previous studies by Reid (1984), Wu, Hsia, Liao, & Tennyson (2008), Ali (2011), Azawei (2017). The results divulged that a) social environment and cognitive factors had significantly positive correlations with students’ satisfaction in a BL course, in which social factors have a higher relation, b) learning climate and perceived usefulness are the two factors having the most significant impact on student satisfaction, while c) students’ learning styles have the lowest correlation, but positive to the other variables. The pedagogical implications and limitations of study are also discussed

Конструкция и характеристики неохлаждаемых болометрических инфракрасных решеток на основе аморфного кремния

Uncooled bolometric type thermal detectors, combined into a matrix and placed into a focal plane array have the following characteristics: low cost, operation at room temperature, compatibility with the silicon CMOS technology, and high detecting performance; therefore recently it became a hot spot in infrared or terahertz detection field. The performance of uncooled infrared focal plane detector arrays depends on the optimization of critical parameters which are determined by geometrical design and the electrical, optical, and thermal physical properties of the detector materials. We report the study of a fabrication process and characterization of two (2D) dimensional arrays of uncooled microbolometers based on silicon (α-Si) thermo-sensing films. Because these arrays substantially reduce sensor size, they are becoming the preferred format for most modern applications

Simulation of the Heavy Charged Particle Impacts on Electrical Characteristics of N-MOSFET Device Structure

The paper presents the results of simulation of the impacts of a heavy charged particle with a value of linear energy transfer equal to 1.81 MeV•cm2 /mg, 10.1 MeV•cm2 /mg, 18.8 MeV•cm2 /mg, 55.0 MeV•cm2 /mg, corresponding to nitrogen ions 15N+4 with energy E = 1.87 MeV, argon 40Ar+12 with energy E = 372 MeV, ferrum 56Fe+15 with energy E = 523 MeV, xenon 131Xe+35 with energy E = 1217 MeV, on electrical characteristics of n-MOSFET device structure when there are variations in the motion trajectory and ambient temperature

Screening for actinomyces isolated from soil with the ability to inhibit Xanthomonas oryzae pv. oryzae causing rice bacterial blight disease in Vietnam

Bacterial blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the major diseases in rice culture of Northen Vietnam, as well as other rice-growing regions of the world. In this study, we isolated and screened for actinomycete strains from Vietnam with the ability to inhibit Xoo isolates from northern Vietnam. From 90 actinomycete strains taken from soil in northern Vietnam in 2010, we screened for their antagonistic activity against 10 races of Xoo causing rice bacterial blight disease. Three actinomycete strains were found to inhibit all 10 Xoo races. Among the three strains, a strain namely VN10-A-44 was shown not to have the ability to produce toxic compounds and was selected for further study. The strain was identified as Streptomyces virginiae by 16S ribosomal RNA gene sequencing. We replaced soybean meal with tofu waste in antibiotic producing medium to improve antagonistic activity of VN10-A-44 against the Xoo pathogen and to make use of tofu waste for large-scale fermentation of VN10-A-44. We found that replacing soybean meal with 20 and 30 g of tofu waste/litter in the antibiotic producing medium gave the largest inhibition zone against the Xoo pathogen.Key words: Xanthomonas oryzae pv. oryzae, rice bacterial blight disease, Streptomyces virginiae, Vietnam

Конструкция и характеристики неохлаждаемых болометрических инфракрасных решеток на основе аморфного кремния

Uncooled bolometric type thermal detectors, combined into a matrix and placed into a focal plane array have the following characteristics: low cost, operation at room temperature, compatibility with the silicon CMOS technology, and high detecting performance; therefore recently it became a hot spot in infrared or terahertz detection field. The performance of uncooled infrared focal plane detector arrays depends on the optimization of critical parameters which are determined by geometrical design and the electrical, optical, and thermal physical properties of the detector materials. We report the study of a fabrication process and characterization of two (2D) dimensional arrays of uncooled microbolometers based on silicon (α-Si) thermo-sensing films. Because these arrays substantially reduce sensor size, they are becoming the preferred format for most modern applications. Неохлаждаемые тепловые детекторы болометрического типа, объединенные в матрицу, размещенную в фокальной плоскости, в последнее время активно применяются в инфракрасном или терагерцовом поле обнаружения, поскольку обладают низкой стоимостью и высокой эффективностью обнаружения, совместимы с кремниевой КМОП-технологией, а также работают при комнатной температуре. Характеристики таких детекторов зависят от оптимизации критических параметров, которые определяются геометрической конструкцией, электрическими, оптическими и тепловыми свойствами применяемых материалов. В статье рассмотрены эксплуатационные характеристики пикселей двумерных массивов неохлаждаемых микроболометров на основе термочувствительных пленок аморфного кремния. Поскольку эти массивы значительно уменьшают размер сенсора, они становятся предпочтительным форматом для большинства современных приложений.

Нитрид-галлиевый транзистор с высокой подвижностью электронов с эффективной системой теплоотвода на основе графена

The self-heating effect is a major problem for gallium nitride electronic, optoelectronic and photonic devices. Average temperature increase and non-uniform distribution of dissipated power in the gallium nitride high electron mobility transistor lead to the forming of a hot spot in the vicinity of the conducting channel and to degradation of the drain current, output power and gain, as well as poor reliability. The purpose of this work is to develop the design using numerical simulation and to study the thermal phenomena that occur in the gallium nitride high-electron mobility transistor with a graphene-based heat removal system. The objects of the research are the structures fabricated on sapphire, silicon and silicon carbide substrates. The subject of the research is the electrical, frequency and thermal characteristics of the gallium nitride high-electron mobility transistor with a graphene-based heat removal system. The calculation results show that the integration of a graphene-based heat removal element into the design of the high electron mobility transistor can effectively mitigate the self-heating effect and thus improve the device performance. The advantage of the proposed concept is that the graphene-based heat removal element is structurally connected with a heat sink and aims at removing heat immediately from the maximum temperature region, providing an additional heat escape channel. The obtained results can be used by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride power electronics.Эффект саморазогрева представляет собой основную проблему для мощных электронных, оптоэлектронных и фотонных приборов на основе нитрида галлия. Среднее увеличение температуры и чрезвычайно неравномерное распределение рассеиваемой мощности в структуре транзистора с высокой подвижностью электронов на основе нитрида галлия, следствием чего является образование области с очень высокой температурой в окрестности проводящего канала, приводит к деградации тока стока, выходной мощности, коэффициента усиления и ухудшению надежности прибора. Цель работы -разработка конструкции с помощью численного моделирования и исследование особенностей тепловых процессов, протекающих в структуре транзистора с высокой подвижностью электронов на основе нитрида галлия с системой теплоотвода на основе графена. Объектом исследования являются структуры, созданные на подложках сапфира, кремния и карбида кремния. Предметом исследования являются электрические, частотные и тепловые характеристики транзистора с высокой подвижностью электронов на основе нитрида галлия с системой теплоотвода на основе графена. Результаты расчетов показывают эффективность внедрения в конструкцию транзистора с высокой подвижностью электронов графенового теплоотводящего элемента, позволяющего уменьшить влияние эффекта саморазогрева и улучшить эксплуатационные характеристики прибора. Преимущество предлагаемой концепции состоит в том, что теплоотводящий элемент на основе графена конструктивно соединен с теплопоглощающим элементом и предназначен для отведения тепла непосредственно от области максимальной температуры. Полученные результаты могут быть использованы предприятиями электронной промышленности Республики Беларусь при создании элементной базы силовой электроники на основе нитрида галлия

Computer simulation of the operational characteristics of a microstrip silicon detector

This paper presents the results of preliminary device and technological simulation and optimization of the operational characteristics of semiconductor microstrip detectors. We investigated the influence of heavy charged particles with linear energy transfers of 1.81 MeV cm2 mg−1, 18.8 MeV cm2 mg−1 and 55.0 MeV cm2 mg−1, corresponding to nitrogen 15N+4 ions with an energy E = 1.87 MeV, iron 56Fe+15 ions with an energy E = 523 MeV and xenon 131Xe+35 ions with an energy E = 1217 MeV, as well as the angle of incidence of the particles and the temperature and voltage on the substrate, on the characteristics of the detector. To improve the characteristics of the detector, a screening experiment was carried out and a series of optimization calculations were performed. The results will be used for the manufacture and testing of design parameters for an experimental batch of the investigated devices