On Armstrong relations for strong dependencies

The strong dependency has been introduced and axiomatized in [2], [3], [4], [5]. The aim of this paper is to investigate on Armstrong relations for strong dependencies. We give a necessary and sufficient condition for an abitrary relation to be Armstrong relation of a given strong scheme. We also give an effective algorithm finding a relation r such that r is Armstrong relation of a given strong scheme G = (U,S) (i.e. Sr = S+, where Sr is a full family of strong dependencies of r, and S+ is a set of all strong dependencies that can be derived from S by the system of axioms). We estimate this algorithm. We show that the time complexity of this algorithm is polynomial in |U| and |S|

Some results related to dense families of database relations

The dense families of database relations were introduced by Järvinen [7]. The aim of this paper is to investigate some new properties of dense families of database relations, and their applications. That is, we characterize functional dependencies and minimal keys in terms of dense families. We give a necessary and sufficient condition for an abitrary family to be R— dense family. We prove that with a given relation R the equality set ER is an R—dense family whose size is at most m(m-1)/2, where m is the number of tuples in R. We also prove that the set of all minimal keys of relation R is the transversal hypergraph of the complement of the equality set ER. We give an effective algorithm finding all minimal keys of a given relation R. We also give an algorithm which from a given relation R finds a cover of functional dependencies that holds in R. The complexity of these algorithms is also esimated

Some problems related to keys and the Boyce-Codd normal form

The aim of this paper is to investigate the connections between minimal keys and antikeys for special Sperner-systems by hypergraphs. The Boyce-Codd normal form and some related problems are also studied in this paper

Some algorithms related to consistent decision table

Rough set theory is useful mathematical tool developed to deal with vagueness and uncertainty. As an important concept of rough set theory, an attribute reduct is a subset of attributes that are jointly sufficient and individually necessary for preserving a particular property of the given information table. Rough set theory is also the most popular for generating decision rules from decision table. In this paper, we propose an algorithm finding object reduct of consistent decsion table. On the other hand, we also show an algorithm to find some attribute reducts and the correctness of our algorithms is proof-theoretically. These our algorithms have polynomial time complexity. Our finding object reduct helps other algorithms of finding attribute reducts become more effectively, especially as working with huge consistent decision table

An Empirical Analysis of the Prominent Roles of Taxations in the Synchronicity on Boost of Maritime Industry in Singapore

This research examines the causal nexuses of the taxations and financial elements in the synchronistic policy that Singapore has applied to radically boost its maritime & offshore fields to develop its economic growths and make Singapore to be a remarkable country in the world in term of ships building volumes, the numbers of ship registries, and the numbers of deadweight in thousands tons arriving at ports nowadays. There are several factors relating to the economic growths and increased numbers of vessels arriving at ports for instant those are the volumes of import & export merchandises, prices of petrochemical and refined oils, services, etc. In this research, it is aimed at decipher the real effectiveness, the interferences, and the prominent roles of corporate tax (TAX) when it is employed together with the domestic credit to private sector (CRE_X1), the real interest rate (RRATE_X2), and the listed stock companies (STOCK_CO) in one synchronous-financial model during the 1980- 2014 period by using the co-integration and vector error correction models for Granger causality tests, and based on the empirical findings, policymakers could find some interesting issues to their developing plans, hopefully. Keywords: Maritime & Offshore Industry, Economic growth, Co-integration, Granger causality tests, Singapore. JEL Classifications: C1; C

Curie Temperature of Diluted Magnetic Semiconductors: the Influence of the Antiferromagnetic Exchange Interaction

The coherent potential approximation and mean field approximation are used to calculate the free energy of the coupled carrier – localized spin system in III-V diluted magnetic semiconductors. Thus the magnetic transition temperature Tc can be determined and its dependence on important model parameters. We show that the strong antiferromagnetic superexchange interaction between nearest neighbour sites considerably reduces the Curie temperature

Some combinatorial characteristics of closure operations

The aim of this paper investigates some combinatorial characteristics of minimal key and antikey of closure operations. We also give effective algorithms finding minimal keys and antikeys of closure operations. We estimate these algorithms. Some remarks on the closeness of closure operations class under the union and direct product operations are also studied in this paper

Validation of Mesocyclops (Copepoda) and community participation as an effective combination for Dengue control in Northern Vietnam

The “Programme Meso-Vietnam” was implemented in Vietnam from October 2007 to December 2010 to reduce dengue and dengue hemorrhagic fever incidence and to improve the quality of life in the four project communes. This dengue control project was based on biological control using Mesocyclops, a larvivorous micro-crustacean, as well as on the establishment of a strong community involvement to educate the population on dengue transmission and to reduce Aedes breeding by removal of containers. During three years, a network of collaborators was responsible for introducing Mesocyclops in all the containers defined as key breeding-sites, and regular activities such as community training workshops, school programmes, clean-up campaigns and health promotion through IEC programmess were performed. To make this programme sustainable, local leadership has been strengthened as well. The use of these larvivorous micro-crustaceans as a biological control strategy against dengue over the medium and long term, when combined with community participation and effective health promotion, demonstrated a significant reduction in dengue vector populations and dengue cases.  In Vietnam, this study reconfirms that there is an ecological alternative to systematic use of insecticides to control dengue vector population. (Abstract word count: 186)Le " Programme Meso-Vietnam " a été mis en œuvre au Vietnam entre octobre 2007 et décembre 2010. Ce programme vise à réduire l'incidence de la dengue et de la fièvre hémorragique de la dengue et à améliorer la qualité de vie dans les quatre communes sélectionnées pour le projet. Ce projet de lutte contre la dengue était basé sur un contrôle biologique assuré par des Mésocyclopes, micro-crustacés larvivores, et sur l'établissement d'une forte implication de la communauté pour éduquer la population sur la transmission de la dengue et pour réduire la reproduction des moustiques Aedes par élimination des conteneurs leur servant de site de ponte. Pendant trois ans, un réseau de collaborateurs a été chargé d'introduire des Mésocyclopes dans tous les conteneurs définis comme des sites de reproduction clés, et des activités régulières telles que des ateliers de formation communautaires, des programmes scolaires, des campagnes de nettoyage et des activités de promotion de la santé via les programmes IEC ont été mises en place. En outre, pour assurer la pérennité de ce programme, le leadership local a été renforcé. L'utilisation de ces micro-crustacés larvivores comme stratégie de contrôle biologique de la dengue à moyen et long terme, associée à une participation communautaire et à une promotion efficace de la santé, a permis d'aboutir à une réduction significative des populations vecteurs de la dengue et des cas de dengue. Au Vietnam, cette étude confirme une fois de plus qu'il existe une alternative écologique à l'utilisation systématique d'insecticides pour lutter contre les vecteurs de la dengue.El “Programa Meso-Vietnam” se implementó en Vietnam desde octubre de 2007 hasta diciembre de 2010 para reducir la incidencia del dengue y la fiebre hemorrágica del dengue y para mejorar la calidad de vida en los cuatro municipios del proyecto. Este proyecto de control del dengue se basaba en el control biológico usando Mesocyclops, un microcrustáceo larvívoro, así como en el establecimiento de una fuerte implicación comunitaria para educar a la población sobre la transmisión del dengue y para reducir la cría de Aedes mediante la eliminación de recipientes. Durante tres años, una red de colaboradores fue responsable de la introducción de Mesocyclops en todos los recipientes definidos como sitios clave para la cría, y se realizaron actividades regulares tales como talleres de formación comunitaria, programas escolares, campañas de limpieza y promoción de la salud a través de programas de IEC. Para hacer sostenible este programa, también se reforzó el liderazgo local. El uso de estos microcrustáceos larvívoros como estrategia de control biológico contra el dengue a medio y largo plazo demostró una reducción significativa de las poblaciones de vectores del dengue y los casos de dengue cuando se combinaba con la participación comunitaria y la promoción eficaz de la salud. En Vietnam, este estudio vuelve a confirmar que existe una alternativa ecológica al uso sistemático de insecticidas para controlar la población de vectores del dengue

The Factors of Consumer Intension of Using Mobile Payment in Vietnam

Purpose: Within the context of emerging mobile technologies, Mobile payment or M-payment has been introduced as the new trend for payment methods bringing more value and convenience to consumers. However, the development of M-payment services is still quite timid in some Southeast Asia countries including Vietnam. This is also the reason and motivation for the author to do this research.   Theoretical framework: The goal of this study is to spot some factors that affect the use behavior (UB) of M-payment consumers in five major metropolises that were most influential on the economy in Vietnam.   Design/methodology/approach: A quantitative questionnaire was used to measure the responses of participants and Partial Least Squares (PLS) method was employed to analyze the collection data as well as test all hypotheses.   Findings: The results indicated that SI has been the important factor leading to the BI to use M-payment followed by SV and SC issues and BI also had a strong influence on the UB of consumers. Since M-payment is still in the infancy stage and is one of the most exciting mobile applications for the next few years in Vietnam, the identification of important factors concerning M-payments.   Research, Practical & Social Implications: To investigate the factors affecting UB of Vietnamese M-payment consumers, the researcher proposed a research model which analyzes the impact of various variables extracted from system quality (ST), service quality (SV), security (SC), social influence (SI) on behavioral intention (BI) to use and BI on M-payment UB.   Originality/value: This study will assist merchants and software developers to design and improve the systems and services to ensure the full acceptance and continuous use of the systems. Finally, a set of suggestions for the subsequent research works also was listed at the end of this study

Propagating arbuscular mycorrhizal fungi associated with coffee plant by using the herbaceous host

Coffee (Coffea spp.) is one of important industrial crops. Additionally, arbuscular mycorrhizal fungi (AMF) provide many benefits for plants such as increasing nutrient uptake, enhancing tolerance in drought and stress condition, etc. Therefore, preservation and propagation of AMF spores collected from coffee’s rhizosphere are necessary for coffee cultivation. The AMF preservation on coffee plant is not feasible because coffee is a long-term plants, which led to study on symbiotic ability of AMF on several short-term host plants (maize (Zea mays), plantain (Plantago spp.), rice (Oryza sativa), beggarticks (Bidens pilosa), and bahia grass (Pensacola bahia)) to maintain AM association. Investigation of symbiosis ability with four types of AMF spores showed that maize had the highest rate of fungal infection. The total number of AMF spore per 50g soil after 3 months of inoculation on maize reached 352 spores, which was 4.1 times higher than that of the origin while the lowest figure recorded in bahia grass is with only 2.3 times