Dynamic lot sizing problem with continuous-time Markovian production cost

This paper develops a polynomial algorithm for obtaining dynamic economic lot sizes in a single product multiperiod production system with the objective of minimizing total production and inventory costs over T periods. It is assumed that production costs are linear, inventory costs are concave, setup costs are zero and backlogging is not permitted in all periods. Moreover, the unit production cost is a stochastic variable, which is evolved according to a continuous-time Markov process over the planning horizon. The model is formulated as a stochastic dynamic programming (DP) optimization with the state variable being unit production cost. Then, it is solved using the backward dynamic programming approach. To justify the application of the proposed model, two practical cases are presented.     

The Deterrent Effect of Whistleblowing on Tax Collections

Abstract

Many countries use tax-related whistleblowing programs, but the evidence on these programs suggests information provided by whistleblowers yields modest tax collections. However, when every citizen could become a whistleblower, deterrence from tax evasion can by itself increase tax collections. We find that tax collections significantly increased after the introduction of the whistleblowing mechanism in Israel in February 2013, although this mechanism directly yielded little or no tax collections. In support of the hypothesis that deterrence led to the increase in tax collections, we find that collections increased in industries with high tax-evasion risk, but not in industries with low tax-evasion risk. Furthermore, the increase in tax collections occurred in corporations, where the timing and magnitude of tax payments are more discretionary, but not from employees, for whom employers directly deduct taxes. Eventually, following reports that the whistleblowing mechanism is ineffective, deterrence diminished and tax collections decreased, suggesting the deterrence effect was temporary.     

A hybrid clustering and classification approach for predicting crash injury severity on rural roads

As a threat for transportation system, traffic crashes have a wide range of social consequences for governments. Traffic crashes are increasing in developing countries and Iran as a developing country is not immune from this risk. There are several researches in the literature to predict traffic crash severity based on artificial neural networks (ANNs), support vector machines and decision trees. This paper attempts to investigate the crash injury severity of rural roads by using a hybrid clustering and classification approach to compare the performance of classification algorithms before and after applying the clustering. In this paper, a novel rule-based genetic algorithm (GA) is proposed to predict crash injury severity, which is evaluated by performance criteria in comparison with classification algorithms like ANN. The results obtained from analysis of 13,673 crashes (5600 property damage, 778 fatal crashes, 4690 slight injuries and 2605 severe injuries) on rural roads in Tehran Province of Iran during 2011–2013 revealed that the proposed GA method outperforms other classification algorithms based on classification metrics like precision (86%), recall (88%) and accuracy (87%). Moreover, the proposed GA method has the highest level of interpretation, is easy to understand and provides feedback to analysts.     

Food heritage and promoting herbal medicine-based niche tourism in Isfahan,Iran

The dynamic and competitive nature of tourism means that surviving commercially may require the emergence of niche tourism. This paper presents a niche tourism sector that emphasizes medicinal plants: herbal medicine-based tourism. This research has two major purposes: to investigate innovation and strategies for promoting herbal-medicine-based tourism and to demonstrate strategies for integrating tourism and medicinal plants for the purpose of education and knowledge transfer. This study was conducted in Isfahan, Iran. The results show that strategies (such as outdoor activities and tourist workshops in herbal medicine parks/farms or in the plants’ natural habitats; training tour guides who are familiar with botany and medicinal plants; and the integration of traditional medicine and tourism to emphasize the therapeutic properties of medical plants) can play a central role in tourism based upon learning about and consuming traditional medicinal herbs. The innovative strategies for promoting this specialized form of tourism are classified into five main categories.     

A Comparative Analysis of the Hedging Effectiveness of Farmgate Milk Prices for New Zealand and United States Dairy Farmers

Journal of Quantitative Economics - This study investigates the effectiveness of hedging and cross-hedging of fluid milk supplied by New Zealand farmers using derivatives offered by the NZX dairy...     

Analysis of travel and tourism competitiveness index in middle-east countries

The purpose of this research is to analyze tourism competitiveness in middle-east countries by using travel and tourism competitiveness index published in the report of the world economic forum. The used model is performed to analyze Promethee model and comparative analysis on the basis of data in 2015 and 2017. The analysis results showed that although Egypt, Iran, Kuwait, Lebanon and yamen improved their situation in comparison to 2015, they couldn’t improve their own competition power in comparison to other middle-east countries, and they were located in the group of countries with lower tourism competitiveness.     

Sustainability Risk Disclosure Practices of Listed Companies in Australia

This paper investigates the extent to which the top 100 ASX listed companies disclosed economic, environmental and social sustainability risk factors during the 2014/15 financial year in light of the changes introducing Recommendation 7.4 to the third edition of the Corporate Governance Principles and Recommendations in 2014. While all companies complied with the Recommendation, questions of substance over form were raised because some companies had risks that were not disclosed according to Recommendation 7.4. Our conclusion outlines how this research contributes to the growing literature on sustainability and corporate governance. We add to the continuing debate on mandatory versus voluntary disclosures, advocating that Australia may need to introduce mandatory guidelines, beyond the ASX, to regulate the disclosure of material economic, environmental and social risks. Additionally, we conclude that Recommendation 7.4 is unlikely to substantially change Australian corporate reporting and disclosure practices – that, for most companies, it is ‘business as usual’. However, under business as usual, we can naturally expect to see further increases in sustainability and alternative reporting frameworks, such as integrated reporting, as well as increasing use of the Internet to report and disclose sustainability risks.     

Key factors affecting the hospital performance: a qualitative study using fuzzy logic

Identifying the key factors affecting the hospital performance helps better planning for hospital high performance. The purpose of this study is to provide a combination of qualitative and quantitative methods to investigate the hospital performance. In the qualitative section of this study, factors associated with hospital performance were detected using literature review, interviews, and expert panels. The findings analyzed by one sample t test and categorized by framework analysis method. In the quantitative section of this study, both direct and indirect relationships between factors were measured by using fuzzy Decision Making Trial and Evaluation Laboratory technique to detect influencing and influenced factors. Finally the key factors affecting the hospital performance were detected.     

On the Effects of Entry in Cournot Markets

In the framework of symmetric Cournot oligopoly, this paper provides two minimal sets of assumptions on the demand and cost functions that imply respectively that, as the number of firms increases, the minimal and maximal equilibria lead to (i) decreasing industry price and increasing or decreasing per-firm output; and (ii) increasing industry price (and decreasing per firm output.) In both cases, per-firm profits are decreasing.
The analysis relies crucially on lattice-theoretic methods and yields general, unambiguous and easily interpretable conclusions of a global nature. As a byproduct of independent interest, new insight into the existence of Cournot equilibrium is developed.