161,454 research outputs found
RESTLESS BANDIT MARGINAL PRODUCTIVITY INDICES II: MULTIPROJECT CASE AND SCHEDULING A MULTICLASS MAKE-TO-ORDER/-STOCK M/G/1 QUEUE
No full textThis paper develops a framework based on convex optimization and economic ideas to formulate and solve approximately a rich class of dynamic and stochastic resource allocation problems, fitting in a generic discrete-state multi-project restless bandit problem (RBP). It draws on the single-project framework in the author´s companion paper “Restless bandit marginal productivity indices I: Single-project case and optimal control of a make-to-stock M/G/1 queue”, based on characterization of a project´s marginal productivity index (MPI). Our framework significantly expands the scope of Whittle (1988)´s seminal approach to the RBP. Contributions include: (i) Formulation of a generic multi-project RBP, and algorithmic solution via single-project MPIs of a relaxed problem, giving a lower bound on optimal cost performance; (ii) a heuristic MPI-based hedging point and index policy; (iii) application of the MPI policy and bound to the problem of dynamic scheduling for a multiclass combined MTO/MTS M/G/1 queue with convex backorder and stock holding cost rates, under the LRA criterion; and (iv) results of a computational study on the MPI bound and policy, showing the latter´s near-optimality across the cases investigated.
Restless bandit marginal productivity indices I: singleproject case and optimal control of a make-to-stock M/G/1 queue
No full textThis paper develops a framework based on convex optimization and economic ideas to formulate and solve by an index policy the problem of optimal dynamic effort allocation to a generic discrete-state restless bandit (i.e. binary-action: work/rest) project, elucidating a host of issues raised by Whittle (1988)Žs seminal work on the topic. Our contributions include: (i) a unifying definition of a projectŽs marginal productivity index (MPI), characterizing optimal policies; (ii) a complete characterization of indexability (existence of the MPI) as satisfaction by the project of the law of diminishing returns (to effort); (iii) sufficient indexability conditions based on partial conservation laws (PCLs), extending previous results of the author from the finite to the countable state case; (iv) application to a semi-Markov project, including a new MPI for a mixed longrun-average (LRA)/ bias criterion, which exists in relevant queueing control models where the index proposed by Whittle (1988) does not; and (v) optimal MPI policies for service-controlled make-to-order (MTO) and make-to-stock (MTS) M/G/1 queues with convex back order and stock holding cost rates, under discounted and LRA criteria
RESTLESS BANDIT MARGINAL PRODUCTIVITY INDICES I: SINGLEPROJECT CASE AND OPTIMAL CONTROL OF A MAKE-TO-STOCK M/G/1 QUEUE
No full textThis paper develops a framework based on convex optimization and economic ideas to formulate and solve by an index policy the problem of optimal dynamic effort allocation to a generic discrete-state restless bandit (i.e. binary-action: work/rest) project, elucidating a host of issues raised by Whittle (1988)´s seminal work on the topic. Our contributions include: (i) a unifying definition of a project´s marginal productivity index (MPI), characterizing optimal policies; (ii) a complete characterization of indexability (existence of the MPI) as satisfaction by the project of the law of diminishing returns (to effort); (iii) sufficient indexability conditions based on partial conservation laws (PCLs), extending previous results of the author from the finite to the countable state case; (iv) application to a semi-Markov project, including a new MPI for a mixed longrun-average (LRA)/ bias criterion, which exists in relevant queueing control models where the index proposed by Whittle (1988) does not; and (v) optimal MPI policies for service-controlled make-to-order (MTO) and make-to-stock (MTS) M/G/1 queues with convex back order and stock holding cost rates, under discounted and LRA criteria.
Conditional Volatility Nexus between Stock Markets and Macroeconomic Variables: Empirical Evidence of G-7 Countries
No full textPurpose: The purpose of this paper is to analyse the relation between stock market volatility and macroeconomic fundamentals for G-7 countries using monthly data over the period from July 1985 to June 2015. Methodology: The empirical methodology is based on two steps: in the first step, we obtain the conditional volatilities of stock market returns and macroeconomic variables through the GARCH family of models. We also incorporate the impact of early 2000s dotcom and the global financial crises. In the second step, we estimate multivariate vector autoregressive (VAR) model to analyze the dynamic relation between stock markets return and macroeconomic variables. Findings: The overall results for G-7 countries indicate a weak volatility transmission from macroeconomic factors to stock market volatility at individual level but the collective impact of volatility transmission is highly significant. Although, the results of block exogeneity indicate a bidirectional causality except for the UK, but the causal linkage is quite weak from stock market to macroeconomic variables. Moreover, the local financial variables excluding interest rate are closely integrated, and the volatility of industrial production growth and oil price are identified as the most significant macroeconomic factors that could possibly influence the directions of stock markets. Originality: This research establishes the nature of the links between stock market and macroeconomic volatility. Research to date has been unable to satisfactorily establish the empirical nature of such links. We believe this paper begins to do this
Restless bandit marginal productivity indices II: multiproject case and scheduling a multiclass make-to-order/-stock M/G/1 queue
No full textThis paper develops a framework based on convex optimization and economic ideas to formulate and solve approximately a rich class of dynamic and stochastic resource allocation problems, fitting in a generic discrete-state multi-project restless bandit problem (RBP). It draws on the single-project framework in the author's companion paper "Restless bandit marginal productivity indices I: Single-project case and optimal control of a make-to-stock M/G/1 queue", based on characterization of a project's marginal productivity index (MPI). Our framework significantly expands the scope of Whittle (1988)'s seminal approach to the RBP. Contributions include: (i) Formulation of a generic multi-project RBP, and algorithmic solution via single-project MPIs of a relaxed problem, giving a lower bound on optimal cost performance; (ii) a heuristic MPI-based hedging point and index policy; (iii) application of the MPI policy and bound to the problem of dynamic scheduling for a multiclass combined MTO/MTS M/G/1 queue with convex backorder and stock holding cost rates, under the LRA criterion; and (iv) results of a computational study on the MPI bound and policy, showing the latter's near-optimality across the cases investigated
Stock returns and foreign investment in Brazil
No full textWe examine the relationship between stock returns and foreign investment in Brazil, and find that the inflows of foreign investment boosted the returns from 1995 to 2005. There was a strong contemporaneous correlation, although not Granger-causality. Foreign investment along with the exchange rate, the influence of the world stock markets, and country risk can explain 73 percent of the changes that occurred in the stock returns over the period. We also find that positive feedback trading played a role, and that the market promptly assimilated new information.stock returns; foreign investment; Brazilian economy
Corporate Governance and Protection of the Rights of Minority Shareholders in China
No full textThe issue of corporate governance in China is examined in this study. We identify several
important governance mechanisms for China’s publicly listed companies and construct four
sets of variables based on these mechanisms. The variables include measures of ownership
structure, the board, managerial incentives, corporate control, and financial transparency. We then create a ranking index for corporate governance (G-index) based on these variables.
Finally, we relate the G- ranking index to measures of corporate performance. We find that
better-governed companies are associated with higher profitability as measured by ROA and
ROE, higher stock market valuation as measured by the ratio of market value and book value
of the net asset, and lower market turnover ratio. The results indicate that good corporate
governance matters greatly in China’s emerging stock market.postprin
Testing the weak-form efficiency in African stock markets
No full text<p>Purpose – The purpose of this paper is to investigate and compare the weak-form efficiency of a set of 24 African continent-wide stock price indices and those of eight individual African national stock price indices.</p>
<p>Design/methodology/approach – Variance-ratio tests based on ranks and signs were used to examine the weak-form efficiency of the 32 stock price indices investigated.</p>
<p>Findings – On average, it was found that irrespective of the test employed, the returns of all the 24 African continent-wide stock price indices examined in the study are less non-normally distributed compared to the eight individual national stock price indices examined. The authors also report evidence of the African continent-wide stock price indices having significantly better weak-form informational efficiency than their national counterparts.</p>
<p>Practical implications – The policy implication of this evidence is that the African equity price discovery process can be significantly improved if African stock markets integrate their operations. Economically, this may contribute to improved liquidity and more efficient allocation of capital, which in turn can be expected to have a positive impact on economic growth.</p>
<p>Originality/value – The paper makes two major contributions to the extant literature. First, it offers for the first time a comparative analysis of the informational efficiencies of a sample of national stock price indices as against African continent-wide stock price indices. Second, there is no prior evidence as to whether African stock markets can improve their informational efficiencies by integrating their operations. The paper fills this gap by demonstrating that the African equity price formation process can be improved if African stock markets integrate their operations.</p>
Modelling Stock Returns in the G-7 and in Selected CEE Economies: A Non-linear GARCH Approach
No full textThis paper investigates conditional variance patterns in daily return series of stock market indices in the G-7 and 6 selected economies of Central and Eastern Europe. For this purpose, various linear and asymmetric GARCH models are employed. The analysis is conducted for Canada, France, Germany, Italy, Japan, the UK and the US for which the TSX, CAC-40, DAX-100, BCI, Nikkei-225, FTSE-100 and DJ-30 indices are respectively considered over the period 1987 to 2002. Furthermore, the official indices of Czech, Hungarian, Polish, Russian, Slovak and Slovene stock markets are also studied, i.e. the PX-50, BUX, WIGI, RFS, SAX-16 and SBI, respectively, over 1991/1995 to 2002. The estimation results reveal that the selected stock returns for the G-7 can be reasonably well modelled using linear specifications whereas the overwhelming majority of the stock indices from Central and Eastern Europe can be much better characterised using asymmetric models. In other words, stock markets of the transition economies exhibit much more asymmetry because negative shocks hit much harder these markets than positive news. It also turns out that these changes do not occur in a smooth manner but happen pretty brusquely. This corroborates the usual observation that emerging stock markets may collapse much more suddenly and recover more slowly than G-7 stock markets.volatility modelling, conditional variance, non-linearity, asymmetric GARCH, G-7, transition economies
Macro economy, stock market and oil prices: Do meaningful relationships exist among their cyclical fluctuations?
No full textThis paper examines the relationship among consumer price index, industrial production, stock market and oil prices in Greece. Initially we use a unified statistical framework (cointegration and VECM) to study the data in levels. We then employ a multivariate VAR model to examine the relationship between the cyclical components of our series. The period of the study is from 1996:1 – 2008:6. Findings suggest that oil prices and the stock market exercise a positive effect on the Greek CPI, in the long run. Cyclical components analysis suggests that oil prices exercise significant negative influence to the stock market. In addition, oil prices are negatively influencing CPI, at a significant level. However, we find no effect of oil prices on industrial production and CPI. Finally, no relationship can be documented between the industrial production and stock market for the Greek market. The findings of this study are of a particular interest and importance to policy makers, financial managers, financial analysts and investors dealing with the Greek economy and the Greek stock market
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