Van nam Le - Academia.edu (original) (raw)

Papers by Van nam Le

arXiv (Cornell University), May 6, 2015

The problem of optimizing distributed database includes: fragmentation and positioning data. Seve... more The problem of optimizing distributed database includes: fragmentation and positioning data. Several different approaches and algorithms have been proposed to solve this problem. In this paper, we propose an algorithm that builds the initial equivalence relation based on the distance threshold. This threshold is also based on knowledge-oriented clustering techniques for both of horizontal and vertical fragmentation. Similarity measures used in the algorithms are the measures developed from the classical measures. Experimental results carrying on the small data set match fragmented results based on the classical algorithm. Execution time and data fragmentation significantly reduced while the complexity of our algorithm in the general case is stable.

Vietnam Journal of Marine Science and Technology

Marine sediment quality at Vietnam’s coastal monitoring stations in 2020 has an average ecologica... more Marine sediment quality at Vietnam’s coastal monitoring stations in 2020 has an average ecological risk impact, with an average SQG-Q index of 0.16. 4-Four out of 24 stations have sediment quality with zero ecological risk impact, including Bach Long Vi, Thuan An, Phan Thiet, and Sa Huynh stations. The remaining stations (20/24 stations) have sediment quality with moderate ecological risk impact. The SQG-Q indices in 2020 and 2019 tend to decrease compared to 2018 and 2017.

Tập san Khoa học và kỹ thuật trường Đại học Bình Dương

This article points to look for the proper methodologies for financial institutionsin Vietnam wit... more This article points to look for the proper methodologies for financial institutionsin Vietnam within the consequence of Covid-19 widespread. Inside an interesting setting,the widespread has coincidently made formative chances for money related issues. Beneaththis circumstance along the quickening handle of computerized change, this article appearsthat monetary educate should concentrate on research and advancement for human capitaland innovation within the post-pandemic period. Such techniques are anticipated toencourage successful competition in terms of item contrasts and ideal costs as well asmaintainable improvement based on budgetary, clientele, handling, and preparingcomponents.

Sustainability

High-energy internal failures of transformers are catastrophic events which are hardly predictabl... more High-energy internal failures of transformers are catastrophic events which are hardly predictable. For this reason, a full-scale controlled experiment represents a valuable learning opportunity to gather accurate information about sequence of events during the very short time in which the failure occurs. Controlled parameters include tank design, material properties, experimental load and measurements. In this paper, we present a detailed investigation using nonlinear finite-element analysis of a 210-MVA transformer high-pressure experiment. We begin by evaluating the relationship between internal arcing pressure rise and tank expansion characteristics. Since this relationship is not linear due to geometric and material nonlinearities, an iterative process is proposed to ensure result accuracy. Stress–strain material properties are retrieved by tension experiments of specimens extracted from the tested tank to enable accurate comparison of numerical and experimental results. It is ...

There are serious problems in the adoption ofinformation technology (IT) for teaching in engineer... more There are serious problems in the adoption ofinformation technology (IT) for teaching in engineering.Professors hesitate to use IT for teaching: they are notfamiliar with the technologies, and know little about thetheories and practices around their use. The research is partof an initiative undertaken by a group of early IT adopters tobuild and share new knowledge related with the use oftechnology for teaching. The paper presents an innovativeapproach to accelerate the adoption of IT for teaching andimprove its value for transferring knowledge. Three types oftechnologies are analyzed: intelligent boards, audienceresponse systems and community-based tools for learning.Practices from superusers are captured using ethnographicmethods. Members of the community validate these practicesthrough experimentation in a learning laboratory. Then aframework of practices is developed and shared within thecommunity’s knowledge base.Index Terms ⎯ IT in teaching, community of practice, bestpractices...

Journal of Economics and Sustainable Development, 2019

This study aims to review previous studies in the field of knowledge sharing. Data being used in ... more This study aims to review previous studies in the field of knowledge sharing. Data being used in this study was collected from researches related to the topic of knowledge sharing. We summarize literature on knowledge sharing in terms of (i) Necessity of knowledge sharing, (ii) Supporting from information and communication technology tools (ICT), (iii) Context of knowledge sharing, (iv) Participants knowledge sharing, (v) Receiver knowledge and (vi) advantages and disadvantages when participating in knowledge sharing. Some implications are recommended for Vietnamese universities to better support knowledge sharing activities in Vietnam and around the world.

The Journal of Internet Banking and Commerce, 2015

2nd IEEE/ACM International Symposium on Cluster Computing and the Grid (CCGRID'02)

This paper describes a proposal to provide a solution to grid applications specific needs in data... more This paper describes a proposal to provide a solution to grid applications specific needs in data transport security. The solution combines different security protocols to secure data transport, integrity and confidentiality. To address the key management part, the solution secures the local DNS server with the DNSSEC extensions, making it become a local certification authority. This design choice solves a dual problem: secret key distribution and scalability of the solution.

Virtual machine is built on group of real servers which are scattered globally and connect togeth... more Virtual machine is built on group of real servers which are scattered globally and connect together through the telecommunications systems, it has an increasingly important role in the operation, providing the ability to exploit virtual resources. The latest technique helps to use computing resources more effectively and has many benefits, such as cost reduction of power, cooling and, hence, contributes to the Green Computing. To ensure the supply of these resources to demand processes correctly and promptly, avoiding any duplication or conflict, especially remote resources, it is necessary to study and propose a reliable solution appropriate to be the foundation for internal control systems in the cloud. In the scope of this paper, we find a way to produce efficient distributed resources which emphasizes solutions preventing deadlock and proposing methods to avoid resource shortage issue. With this approach, the outcome result is the checklist of re-sources state which has the poss...

Journal of Food Processing and Preservation, 2015

ABSTRACT

2014 International Conference on Smart Computing, 2014

ABSTRACT An allocation of resources to a virtual machine specifies the maximum amount of each ind... more ABSTRACT An allocation of resources to a virtual machine specifies the maximum amount of each individual element of each resource type that will be utilized, as well as the aggregate amount of each resource of each type. An allocation is thus represented by two vectors, a maximum elementary allocation vector and an aggregate allocation vector. There are more general types of resource allocation problems than those we consider here. In this paper, we present an approach for improving parallel deadlock detection algorithm, to schedule the policies of resource which supply for resource allocation in heterogeneous distributed platform. Parallel deadlock detection algorithm has a run time complexity of O(min(m,n)), where m is the number of resources and n is the number of processes. We propose the algorithm for allocating multiple resources to competing services running in virtual machines on a heterogeneous distributed platform. The experiments also compare the performance of the proposed approach with other related work.

PLoS ONE, 2014

There is growing evidence from both behavioral and neurophysiological approaches that primates ar... more There is growing evidence from both behavioral and neurophysiological approaches that primates are able to rapidly discriminate visually between snakes and innocuous stimuli. Recent behavioral evidence suggests that primates are also able to discriminate the level of threat posed by snakes, by responding more intensely to a snake model poised to strike than to snake models in coiled or sinusoidal postures (Etting and Isbell 2014). In the present study, we examine the potential for an underlying neurological basis for this ability. Previous research indicated that the pulvinar is highly sensitive to snake images. We thus recorded pulvinar neurons in Japanese macaques (Macaca fuscata) while they viewed photos of snakes in striking and non-striking postures in a delayed non-matching to sample (DNMS) task. Of 821 neurons recorded, 78 visually responsive neurons were tested with the all snake images. We found that pulvinar neurons in the medial and dorsolateral pulvinar responded more strongly to snakes in threat displays poised to strike than snakes in non-threat-displaying postures with no significant difference in response latencies. A multidimensional scaling analysis of the 78 visually responsive neurons indicated that threat-displaying and non-threatdisplaying snakes were separated into two different clusters in the first epoch of 50 ms after stimulus onset, suggesting bottom-up visual information processing. These results indicate that pulvinar neurons in primates discriminate between poised to strike from those in non-threat-displaying postures. This neuronal ability likely facilitates behavioral discrimination and has clear adaptive value. Our results are thus consistent with the Snake Detection Theory, which posits that snakes were instrumental in the evolution of primate visual systems.

Studies in Computational Intelligence, 2010

In this paper, we introduce an approach for designing and deploying organizations on large scale ... more In this paper, we introduce an approach for designing and deploying organizations on large scale Multi-Agent Robotic Systems. Lying on the well-known organizational meta-model AGR, we propose a role assignment protocol for automatically distributing the roles over the robots. We have run a series of simulations to validate the approach’s feasibility. The simulations show that the protocol is well scalable

2009 21st IEEE International Conference on Tools with Artificial Intelligence, 2009

Exploration of an unknown environment is one of the major applications of Multi-Robot Systems. Ma... more Exploration of an unknown environment is one of the major applications of Multi-Robot Systems. Many works have proposed multi-robot coordination algorithms to accomplish exploration missions based on multi-agent techniques. Some of these works focus on multi-robot exploration under communication constraints. In this paper, we propose an original way to formalize and solve this issue. Our proposal relies on distributed constraint satisfaction problems (disCSP) which are an extension of classical constraint satisfaction problems (CSP). Compared to other works, our proposal is fully distributed and guaranties the exploration of an unknown environment with maintenance of connectivity between all the members of a robots' team.

2009 IEEE International Conference on Robotics and Automation, 2009

Maintaining the network connectivity in mobile Multi-Robot Systems (MRSs) is a key issue in many ... more Maintaining the network connectivity in mobile Multi-Robot Systems (MRSs) is a key issue in many robotic applications. In our view, the solution to this problem consists of two main steps: (i) making robots aware of the network connectivity; and (ii), making use of this ...

2009 IEEE-RIVF International Conference on Computing and Communication Technologies, 2009

Maintaining the Network Connectivity in Mobile Multi-Robot Systems (MRSs) is a key issue in many ... more Maintaining the Network Connectivity in Mobile Multi-Robot Systems (MRSs) is a key issue in many robotics applications. In our view, the solution to this problem consists of two steps: (i) making robots aware of the network connectivity; and (ii), making use of this knowledge in order to plan robots tasks without compromising the connectivity. We propose a novel distributed algorithm that will be executed on individual robots to make robot be aware of the network connectivity (i). We also rigorously formalize the problem of checking the robustness of a wireless network based on the conception of Connectivity-Awareness. The algorithm featured with very low communication overhead in comparison with existing works.

Future Data and Security Engineering, 2014

Our investigation aims at constructing oblique decision stump forests to classify very large numb... more Our investigation aims at constructing oblique decision stump forests to classify very large number of twitter messages (tweets). Twitter sentiment analysis is not a trivial task because tweets are short and getting generated at very fast rate. Supervised learning algorithms can thus be useful to automatically detect positive or negative sentiments. The pre-processing step performs the cleaning tasks and the representation of tweets using the bag-of-words model (BoW). And then we propose oblique decision stump forests based on the linear support vector machines (SVM) that is suitable for classifying large amounts of high dimensional datapoints. The experimental results on twittersentiment.appspot.com corpora (with 1,600,000 tweets) show that our oblique decision stump forests are efficient compared to baseline algorithms.

Advances in Natural Sciences: Nanoscience and Nanotechnology, 2014

ABSTRACT Electrochemical DNA (E-DNA) sensors, which are rapid, reagentless and readily integrated... more ABSTRACT Electrochemical DNA (E-DNA) sensors, which are rapid, reagentless and readily integrated into microelectronics and microfluidics, appear a promising alternative to optical methods for the detection of specific nucleic acid sequences. In keeping with this, a large number of distinct E-DNA architectures have been reported to date. Most, however, suffer from one or more drawbacks, including low signal gain, signal-off behavior or instability. To remedy these problems, we report here the development of a signal-on E-DNA architecture that achieves both high signal gain and good stability. This new sensor employs a commercially synthesized, asymmetric hairpin DNA as its recognition and signaling probe, the shorter arm of which is labeled with a redox reporting methylene blue at its free end. Unlike all prior E-DNA architectures, in which the recognition probe is attached via a terminal functional group to its underlying electrode, the probe employed here is affixed using a thiol group located internally, in the turn region of the hairpin. Hybridization of a target DNA to the longer arm of the hairpin displaces the shorter arm, allowing the reporter to approach the electrode surface and transfer electrons. The observed signal gain is sufficient to achieve a demonstrated detection limit of 25 pM.

2009 IEEE International Workshop on Safety, Security & Rescue Robotics (SSRR 2009), 2009

The global climate change induces an increase, in terms of frequency and devastating power, of na... more The global climate change induces an increase, in terms of frequency and devastating power, of natural disasters (particularly in developing countries). For facing this, there is a growing need for robotic assistance, for collecting information, managing disaster situation, rescuing victims and preserve human lives. It is one of the means recommended by the UNPD (United Nations Program for Development), which consist in the deployment of onfield automated monitoring, surveillance and reconnaissance systems. This paper outlines the research performed in the AROUND (Autonomous Robots for Observation of Urban Networks after Disasters) project. This project addresses the issue of developing a search and rescue multi-robot systems taking into account specific constraints of developing countries.