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Search Results: 1 - 10 of 6519 matches for " Nguyen Ha "
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Selection combining for noncoherent decode-and-forward relay networks
Nguyen Ha,Nguyen Ha
EURASIP Journal on Wireless Communications and Networking , 2011,
Abstract: This paper studies a new decode-and-forward relaying scheme for a cooperative wireless network composed of one source, K relays, and one destination and with binary frequency-shift keying modulation. A single threshold is employed to select retransmitting relays as follows: a relay retransmits to the destination if its decision variable is larger than the threshold; otherwise, it remains silent. The destination then performs selection combining for the detection of transmitted information. The average end-to-end bit-error-rate (BER) is analytically determined in a closed-form expression. Based on the derived BER, the problem of choosing an optimal threshold or jointly optimal threshold and power allocation to minimize the end-to-end BER is also investigated. Both analytical and simulation results reveal that the obtained optimal threshold scheme or jointly optimal threshold and power-allocation scheme can significantly improve the BER performance compared to a previously proposed scheme.
Random forest classifier combined with feature selection for breast cancer diagnosis and prognostic  [PDF]
Cuong Nguyen, Yong Wang, Ha Nam Nguyen
Journal of Biomedical Science and Engineering (JBiSE) , 2013, DOI: 10.4236/jbise.2013.65070
Abstract:

As the incidence of this disease has increased significantly in the recent years, expert systems and machine learning techniques to this problem have also taken a great attention from many scholars. This study aims at diagnosing and prognosticating breast cancer with a machine learning method based on random forest classifier and feature selection technique. By weighting, keeping useful features and removing redundant features in datasets, the method was obtained to solve diagnosis problems via classifying Wisconsin Breast Cancer Diagnosis Dataset and to solve prognosis problem via classifying Wisconsin Breast Cancer Prognostic Dataset. On these datasets we obtained classification accuracy of 100% in the best case and of around 99.8% on average. This is very promising compared to the previously reported results. This result is for Wisconsin Breast Cancer Dataset but it states that this method can be used confidently for other breast cancer diagnosis problems, too.

Quantitative and qualitative changes of humus in whole soils and their particle size fractions as influenced by different levels of compost application  [PDF]
Thu Ha Nguyen, Haruo Shindo
Agricultural Sciences (AS) , 2011, DOI: 10.4236/as.2011.21001
Abstract: Effect of long-term application (ca. 30 years) of compost at different levels on humus composi-tion of whole soils and their particle size frac-tions in a field subjected mainly to double cropping (barley and paddy rice) was investi-gated. Soil samples were collected from three plots of different types of management: (a) F plot, only chemical fertilizers containing N, P and K were applied; (b) F+LC plot, both chemi-cal fertilizers and a low level of compost were applied; (c) F+HC plot, both chemical fertilizers and a high level of compost were applied (the amount of compost applied in the F+HC plot was three times larger than that applied in the F+LC plot). Each soil sample was divided into coarse sand- (CSA), medium sand-(MSA) and fine sand-(FSA) sized aggregate, silt-sized ag-gregate (SIA) and clay-sized aggregate (CLA) fractions by wet-sieving and sedimentation. In addition, the CSA and MSA fractions were sub-divided into “mineral particles” (MP) and “de-cayed plants” (DP) by a density fractionation. Humus composition was influenced depending upon the level of compost applied. The applica-tion induced an increase in the amounts of total humus (TH), humic acid (HA) and fulvic acid (FA) in the whole soil and many size fractions, par-ticularly, SIA fraction. The increase was re-markable in the F+HC plot. In the CSA and MSA fractions, the amounts of TH, HA and FA were much larger in the CSA- and MSA-DP fractions than in the CSA- and MSA-MP fractions. The amounts of TH, HA and FA in the SIA fraction were larger than those in the CLA fraction for the F+HC and F+LC plots, and the reverse was true for the F plot. On the other hand, the de-grees of humification of humic acids in whole soils and many size fractions, particularly SIA fraction, decreased by compost application. The decrease was markedly in the F+HC plot. These findings suggest that the SIA fraction play an important role in the quantitative and qualitative changes of humus, including HA and FA, as in-fluenced by a long-term compost application.
Effects of different levels of compost application on amounts and distribution of organic nitrogen forms in soil particle size fractions subjected mainly to double cropping  [PDF]
Thu Ha Nguyen, Haruo Shindo
Agricultural Sciences (AS) , 2011, DOI: 10.4236/as.2011.23030
Abstract: Effects of different levels of compost application on the amounts and percentage distribution of organic N forms in whole soils and particle size fractions were investigated. Soil samples were collected from three plots: (a) F, only chemical fertilizers; (b) F+LC, chemical fertilizers plus low level of compost; (c) F+HC, chemical fertilizers plus high level of compost. Each soil sample was divided into five fractions: coarse sand-sized aggregate (CSA), medium sand-sized aggregate (MSA), fine sand-sized aggregate (FSA), silt-sized aggregate (SIA) and clay-sized aggregate (CLA) fractions. The sand fractions were subdivided into decayed plants (DP) and mineral particles (MP). The amounts of total N and different organic N forms in the whole soils as well as size fractions generally increased with increasing the amount of compost. In the whole soils, percentage distribution of non-hydrolysable-N and amino sugar-N increased by compost application while the distribution values of the hydrolysable ammonium- N and unidentified-N decreased. The application did not affect the distribution degree of amino acid-N. In the size fractions, the distribution values of most organic N forms increased in the CSA-DP, MSA-DP and FSA-DP fractions by compost application. In the CLA fractions, the amounts and percentage distribution of organic N forms were the highest, although the application caused decreases in their distribution values. These findings indicate that the CLA fraction merit close attention as an important reservoir of various organic N.
Contact with Biological Parents for Children in Residental Care: A Vietnam Study  [PDF]
Nguyen Ba Dat, Nguyen Van Luot, Nguyen Ha Thanh
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.611021
Abstract: Children living in residential care have a degree of separation from their parents and other family members. Based on attachment theory, this study was conducted to analyze the contact between these children and their biological parents, and the factors affecting this contact. The sample included 382 children (orphans, abandoned or helpless children, children whose parents are deprived of custody or are unable to raise a child) living in residential centers located in North, Central and South of Vietnam. Data were obtained by semi-structured interviews. The results showed that, on average, children contact their parents and family members once a month. In addition, variables such as family image in children’s mind and joyfulness when meeting parents are the best predictors of contact between children and parents, family members. The contact between children and parents is arguably considered as a form of consolidation and maintenance of emotional relationship.
Analysis of the Strategy of Chinese Enterprises to Open up Vietnam Market—A Case Study of a Hong Kong Invested Enterprise Entering the Vietnamese Market  [PDF]
Zhen Li, Nguyen Thi Thu Ha
Open Journal of Business and Management (OJBM) , 2017, DOI: 10.4236/ojbm.2017.54058
Abstract:
Under the background of economic globalization, the concept of “global village” is constantly strengthened, and the links between countries are becoming more and more closely. More and more Chinese enterprises have stepped into the world. After the 2008 financial crisis, there were signs of recession and weakness in the European and American markets, and many Chinese enterprises began to turn their attention to the Southeast Asian market, which had not yet been saturated, and hope to win the competition through geographical advantages and price advantages. China and Vietnam are neighbors, are similar in political systems and cultural, but Chinese enterprises are often failed to develop Vietnam market. How to accurately grasp the characteristics of the Vietnamese market, and how to improve the effectiveness of enterprise market development, based on this, this passage is written for Chinese enterprises to explore similar features of the market to provide reference experience. This article is written through a Hong Kong LED lighting enterprises to develop the Vietnamese market successful experience, and put forward new strategies and new ideas for Chinese enterprises to open up the Vietnamese market.
Vietnam Economic Structure Change Based on Vietnam Input-Output Tables 2012 and 2016  [PDF]
Nguyen Ho Phi Ha, Bui Trinh
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.84047
Abstract: National economic structure is defined as the composition and patterns of various components of the national economy such as: production, value added, consumption, gross capital formation, export, import and gross value added. Structural change is conceptualized as the change in relative importance of the aggregate indicators of the economy. It implies that changes of intra-sectoral and inter-sectoral lead to changes in final demand, output, value added and import. This paper seeks to answer some questions: 1) What would be the impact on the power of dispersion and the sensitivity of dispersion by sectors? 2) What would be the impact on value added induced by final demand? and 3) How would the final demand impact the level of import? The main finding in this study is to find a sectoral structure and a factor of the final demand for Vietnam’s development.
The Impact of Governance on Entrepreneurship Development in ASEAN+1 Countries: Evidence from World Bank Datasets  [PDF]
Thai Thanh Ha, Nguyen Ngoc Chau, Nguyen Trung Hieu
Modern Economy (ME) , 2016, DOI: 10.4236/me.2016.75056
Abstract: This research explores the impact of the governance indices on the development of entrepreneurship in the context of ASEAN+1 countries which include China as an important partner to South East Asian nations in almost all aspects of ASEAN development. With the use of the database of the World Bank on the World Governance Indices and Entrepreneurship known as Doing Business for ASEAN+1 countries, natural logarithm regression analysis was adopted to figure out the extent to which governance would exert its impact on the entrepreneurship development in the member countries of ASEAN as well as China. On the basis of the study findings, conclusions and recommendations were to be drawn for policy modernization in ASEAN+1 context.
Consumption of antibiotics in a small Pacific island nation: Samoa.
Norris P,Nguyen HA
Pharmacy Practice (Granada) , 2007,
Abstract: High levels of antibiotic use contribute to development of antibiotic resistance. There is little known about levels of antibiotic use in Samoa, although anecdotally, there are high levels of use, and a strain of methicillin-resistant Staphylococcus aureus may have developed there. The study aimed to gather basic data on levels of antibiotic use in Samoa.All those who import medicines into Samoa were interviewed; invoices, prescription records in hospitals, pharmacies and health centres were reviewed; and prospective observation was carried out in private pharmacies. Analysis of orders made in one year provided an estimate of overall antibiotic consumption of 37.3 Defined Daily Doses (DDDs) per 1000 inhabitant days. Penicillins comprised 63% of DDDs used. Antibiotics were around a third of all prescribed drugs in hospitals and pharmacies, and 44% of those dispensed in health centres. Approximately two-thirds of prescriptions dispensed included an antibiotic. A quarter of antibiotic sales in pharmacies were without a prescription.Samoa has high rates of use of antibiotics and very high reliance on penicillins, compared to other developing countries. Levels of prescribing are high compared with other developing nations. It is feasible to calculate total consumption of medicines in very small developing nations.
The Effect of Firm’s Growth on Firm Survival in Vietnam
Nguyen Minh Ha
International Business Research , 2013, DOI: 10.5539/ibr.v6n5p142
Abstract: With the dataset of 7,962 firms in Vietnam and using the Cox proportional hazard model, the main findings are drawn that the relationship between the firm’s growth (both in employment and in assets) and the survival is positive and non-linearity, and as increasing the growth, the effect of firm’s growth on the firm survival is diminishing. In addition, we also find that the presence of the domestic private and the foreign firms can improve the survival chances, compared to the state firms; The firm size in assets and initial debt have positive relationships with firm survival; Earning before taxes over labour in year t-1 and the return on assets in year t-1 are important and have positive impacts on firm survival in year t, whereas the leverage in year t-1 has a negative impact on the probability of survival in year t for firms in Vietnam.
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