Trường Đại học Bách khoa - Đại học Quốc gia Thành phố Hồ Chí Minh

Today, enterprise resource planning system (ERP) becomes popular and it is implemented in most business (in all fields and sizes) all over the world as well as in Vietnam. However, according to consultant experts, ERP projects, though on a large scale with high cost, entail low success rate. For Vietnamese contexts, those findings above are all the more true, because most of Vietnamese enterprises are on a small scale with short-time computerization access, lack of understanding of enterprise systems, and lack of financial resources. This research focuses on exploring key factors affecting the success of ERP projects in Vietnam. Through case studies and data collection, using SPSS for data analysis, key factors affecting the success of ERP projects are listed on such a descending order as follows: Characteristics of ERP team, Quality of consultancy, Characteristics of end-users and Characteristics of business. From the abovementioned analysis, suggestions for ensuring success of ERPs in Vietnam are also proposed.

This article deals with optimal nesting problem when parts are cut from rectangular sheet in the footwear industry. The objective of the research is minimizing the waste of material or maximizing the number of parts to be cut from sheet materials. By generating the mathematical models and building up their algorithms, the software for solving problem dedicates to a number of industries for saving time and minimizing waste of material, and increasing the cutting productivity.

Basing on collecting and classifying the researches in soil mixing column method, and applying soil mixing column method at Sai Gon East West highway, this article wants to state and analysis the factors that effect strength and stability of mixing column. It also has some comments of applying this method in soil improvement.

Water is a resource needed in all aspects of life and is regarded as a decisive factor for Earth's ecosystems survival. However, water resource has also become a limiting factor of social and economic development. For cities of the developing world, water is increasingly playing a vital role in sustainable urban development. Since economic reform known as “Doi Moi" (renovation) in 1986, Ho Chi Minh City, Vietnam, has undergone the rapid growth of urbanization and industrialization. As a result, the City has experie critical environmental challenges in which water use and management have placed constraints on its sustainable development. These striking challenges include water shortage, pollution and depletion of surface and groundwater sources. The underlying reasons can be attributed to inadequate management practices. The purpose of this paper is to provide an overview of rapid urbanization and growing water resource problems. It also examines the management practices and analyze the root causes of water resource issues in the course of sustainable development.

This paper proposes an outage analysis framework for cooperative cognitive networks with proactive relay selection and selection combining (SC) under licensed outage constraint, maximum transmit power constraint, independent non-identical (i.n.i) fading distributions, erroneous channel information, and licensed users’ interference. Towards this end, we firstly suggest power allocation for unlicensed transmitters to satisfy power constraints and account for erroneous channel information and licensed users’ interference. Then, we propose an exact closed-form outage probability formula for the unlicensed network to promptly evaluate system performance and provide useful insights into performance limits. Multiple results show performance trade-off between the unlicensed network and the licensed network, error floor in the unlicensed network, considerable system performance degradation owing to erroneous channel information and licensed users’ interference, and significant performance enhancement due to the increase in the number of relays.

This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.

The third general mobile system (3G)'s purpose supports many kinds of services for everyone at anytime and anywhere. These include such as: high speed data transmission, figure data and multimedia service up to 2Mbps beside traditional voice service. With data rate up to 2Mbps, it is very necessary and important to enhance the transmission, line reliability in 3G. Channel coding is often used in digital mobile system in order to protect the information bits against interference and reduce the number of error bits. A code with Shannon limit performance is ideal, but so far, has not been achieved in practical. The only practical code that comes close to the Shannon limit is RSC Turbo code (Recursive Systematic Encoder). The excellent performance funtion of Turbo code achieve near Shannon limit in case the large frame size on the AWGN channel (Additive White Gaussian Noise). According to IMT-2000 specification, Turbo code is accepted as a channel coding method for large frame data services by 3GPP(W-CDMA) and 3GPP2 (cdma2000).

Reading plays a vital role in improving second/foreign language learning as it can encourage the development of autonomous learners. Furthermore, ESL/EFL learners’ use of reading strategies can be affected by their learning motivation, which can result in the high or low frequent use of reading strategies in reading comprehension. The present study, therefore, investigated the motivation in English language learning and the use of reading strategies among English-majored freshmen at a university in Bac Lieu province, Vietnam. A questionnaire was used to collect data from 180 English-majored freshmen, six of whom took part in semi-structured interviews. The results showed that participants had a high level of motivation in English language learning, and their metacognitive strategies worked better with their reading comprehension than their cognitive and social/affective strategies. The study further unraveled that the more participants were motivated in English language learning, the more they employed metacognitive and cognitive strategies in reading comprehension.

We research on absolute positioning using Beidou pseudo-range measurements collected in Ho Chi Minh City. Positional accuracy achieved is 2.3m, 4.5m and 3.9m for the North, East and height components compared to (0.8, 0.9, 1.7) of GPS and (2.0, 1.9, 4.1) of GLONASS. This result shows that in Vietnam we can use only BEIDOU system for positioning and also opens the possibility of incorporating positioning satellite systems to improve accuracy.

Sleep is very important for the health. Analyzing the polysomnography (PSG) helps us get valuable information to assess the quality of sleep. In this work, we develop a program to automatically detect the transition from wakefulness to sleep in adults. The accurate detection of the point of sleep onset occurs in the first time is useful for assessing the micro-structure of sleep. The proposed method is analyzed polysomnography of 30 healthy volunteers, using data of one channel Electroencephalography, Electrooculography and chin Electromyography. The algorithm automatically analyzes every second according to American Academy of Sleep Medicine (AASM) standards with the latest version. The results obtained under two levels: identify and list the epoch occurred the transition, and exact the time of the shift occurred. With more than 85% in accuracy, the study shows the feasibility to provide timely warning. This approach opens up developing a system in real-time warning: doze off in student, drowsiness, sleepiness when driving or working. It helps us to examine the brain's response to external stimuli to reduce the time of sleep latency.