316 research outputs found

    Clustering High Dimensional Data Using SVM

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    The Web contains massive amount of documents from across the globe to the point where it has become impossible to classify them manually. This project’s goal is to find a new method for clustering documents that are as close to humans’ classification as possible and at the same time to reduce the size of the documents. This project uses a combination of Latent Semantic Indexing (LSI) with Singular Value Decomposition (SVD) calculation as well as Support Vector Machine (SVM) classification. With SVD, data sets are decomposed and can be truncated to reduce the data sets size. The reduced data set will then be used to cluster. With SVM, clustered data set is used for training to allow new data to be classified based on SVM’s prediction. The project’s result show that the method of combining SVD and SVM is able to reduce data size and classifies documents reasonably compared to humans’ classification

    Joint power allocation for MIMO-OFDM full-duplex relaying communications

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    © 2017, The Author(s). In this paper, we address the problem of joint power allocation in a two-hop MIMO-OFDM network, where two full-duplex users communicate with each other via an amplify-and-forward relay. We consider a general model in which the full-duplex relay can forward the received message in either one-way or two-way mode. Our aim is to maximize the instantaneous end-to-end total throughput, subject to (i) the separate sum-power constraints at individual nodes or (ii) the joint sum-power constraint of the whole network. The formulated problems are large-scale nonconvex optimization problems, for which efficient and optimal solutions are currently not available. Using the successive convex approximation approach, we develop novel iterative algorithms of extremely low complexity which are especially suitable for large-scale computation. In each iteration, a simple closed-form solution is derived for the approximated convex program. The proposed algorithms guarantee to converge to at least a local optimum of the nonconvex problems. Numerical results verify that the devised solutions converge quickly, and that our optimal power allocation schemes significantly improve the throughput of MIMO-OFDM full-duplex one-way/two-way relaying over the conventional half-duplex relaying strategy

    Testing for Food market integration: A study of the Vietnamese paddy market

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    With its increasing integration into the world economy, agricultural exports and rural incomes in Vietnam have increased substantially in recent years. At the sub-national level, however, there are concerns that not all regions and categories of agricultural producers have and will benefit from the ongoing liberalization of agricultural markets. Vietnam's elongated geography and lack of spatial market integration pose special problems in this regard. Accordingly, this study aims to answer three interrelated questions: (a) whether there is spatial integration between paddy markets in the North and South of Vietnam; (b) whether there is spatial integration in paddy markets within the North and within the South; and, (c) if within-region integration is stronger and faster than between-region integration. The empirical model we develop to answer these questions, uses estimates of transfer costs to generalize the well known model of spatial market integration due to Ravallion to allow for the possibility of threshold effects. A sequential testing strategy is developed which progressively tests for market segmentation, the number of thresholds, long-run market integration, common dynamics/informational efficiency, and (a strict version of) the 'Law' of One Price within an error-correction framework. When the unrestricted version of this model is estimated using monthly paddy prices for eight markets between 1993 and 2006, we find weak evidence of market integration between paddy markets in the North and South of Vietnam with an absence of threshold effects. However, there is evidence of both threshold effects and stronger forms of spatial market integration for paddy markets within the North and within the South, with at least 60% percent of price changes being transmitted between markets within one month whenever price spreads exceeds their upper or lower thresholds. The extent and speed of price transmission within regional paddy markets is generally faster in the South than the North of Vietnam. However, the instantaneous version of the 'Law' of One Price, which requires full price adjustment to occur within a month, only holds for a few regimes and market pairs. Three main policy implications flow from these results. First, since there is limited evidence of integration between paddy markets in the North and South of Vietnam, national level policies cannot be relied upon to stabilize or support paddy prices.Second, since there is evidence of spatial market integration within the Red River and Mekong River deltas, paddy markets within these regions can be relied upon to transmit price signals between deficit and surplus areas relatively well. Third, since the speed and extent of price transmission is relatively rapid within the North and within the South of Vietnam, the private sector trade can be relied upon to transfer rice and paddy between markets in an efficient manner. Problems might, however, emerge if large demand-supply imbalances were to emerge between the North and South, as transfer costs would prevent private sector trade taking place. In these circumstances, the public sector might need to intervene, in a consistent and market friendly way, to ensure adequate food supplies in the short-term.Market integration; Paddy market; Error-correction; Spatial integration; Vietnam

    Precoding design for Han-Kobayashi's signal splitting in MIMO interference networks

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    © 2017 The Institute of Electronics, Information and Communication Engineers. For a multiuser multi-input multi-output (MU-MIMO) multicell network, the Han-Kobayashi strategy aims to improve the achievable rate region by splitting the data information intended to a serviced user (UE) into a common message and a private message. The common message is decodable by this UE and another UE from an adjacent cell so that the corresponding intercell interference is cancelled off. This work aims to design optimal precoders for both common and private messages to maximize the network sum-rate, which is a highly nonlinear and nonsmooth function in the precoder matrix variables. Existing approaches are unable to address this difficult problem. In this paper, we develop a successive convex quadratic programming algorithm that generates a sequence of improved points. We prove that the proposed algorithm converges to at least a local optimum of the considered problem. Numerical results confirm the advantages of our proposed algorithm over conventional coordinated precoding approaches where the intercell interference is treated as noise

    Asian Values and Human Rights: A Vietnamese Perspective

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    This paper examines the impact of the ideology of ‘Asian Values' on the legal norms and practices that frame the recognition and protection of human rights in Vietnam. Specifically, the paper focusses on the extent to which Asian Values has been deployed to discourage the adoption of international human rights norms and practices in the context of Vietnam’s rapid economic development since the mid- 1980s. The paper first sketches the adoption of Asian Values in Vietnam’s politics and society. Cultural and political factors that have shaped the conception of human rights are reviewed. Human rights language and norms, as manifest in political ideologies, policies and laws are then analysed, with particular reference to the different versions of Vietnam’s Constitution. It is shown that both the Communist Party of Vietnam (CPV) and the State of Vietnam have clearly articulated Asian Values in formulating their conceptions of human rights. This outcome is argued to result from the fact that Vietnamese political leaders, alike with Lee Kwan Yew in Singapore, the progenitor of Asian Rights, have been strongly influenced by Confucian ideals of governance. Confucianism is not, however, the only basis for political ideas in Vietnam. Although Vietnam is a market economy it remains a one- party state  controlled  by  the  CPV.  The  Marxist-Leninist  principles  on  which the current State of Vietnam was based at its inception in 1975 remain intact. This ideology was however layered onto generations of collectivist principles embodied in the dominant agrarian society. The influence of Asian Values, on the recognition of and support for human rights in Vietnam has, however, been largely negative rather than positive, especially in relation to recognising civil and political rights as codified in universal human rights instruments. Thus, the protection and promotion of human rights in Vietnam, going forward, essentially mandates eliminating the influence of Asian Values in the ideology of political leaders and in the wider society. Key words: Human rights, Asian Values, democracy, constitution, Communist Party, Vietna

    The spatial integration of paddy markets in Vietnam

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    Board Independence and Financial Performance: Empirical Evidence on Mediating Role of Market Competition From the Vietnamese Market

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    Purpose: The aim of this study is to examine the effect of board independence on the financial performance of companies listed on the Vietnamese stock exchanges with the mediating role of market competition.   Theoretical framework: The topic is based on agency theory, resource dependency theory and stewardship theory. The independence of the board of directors (BOD) is measured in two aspects: the duality and the non-executive members of BOD. This study approaches the measurement of market competition according to the Herfindahl-Hirschman index (HHI). After calculating the HHI, the study will classify companies in a highly competitive market or a low competitive market.   Design/methodology/approach: The study uses secondary data from the financial statements of companies listed on the Vietnamese stock market with the collection period from 2016 to 2020. The data analysis methods comprise of Pooled ordinary least squares (OLS), Fixed effects model (FEM), Random effects model (REM) and Generalized method of moments estimation (GMM).   Findings: The results of GMM showed that CEO duality is found to have a negative effect on the financial performance of listed firms. Meanwhile, the statistical evidence shows that the percentage of non-executive board members and market competition positively affect the financial performance. In addition, the evidence showed that market competition could reduce the positive influence of the percentage of non-executive board members on financial performance of listed companies.   Research, Practical & Social implications: The study has proposed some governance implications to improve the financial performance of listed firms such as limiting CEO duality, increasing the percentage of non-executive board members and empower the management board in a highly competitive market and choosing the appropriate size of the board.   Originality/value: The value of the study is to provide more scientific basis for policy makers in Vietnam and help listed companies choose and make decisions related to BOD to improve financial efficiency
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