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.     

Impact of Financial Development on the Environmental Quality in Iran

In recent decades, undesirable environmental changes, such as global warming and greenhouse gases emission, have raised worldwide concerns. In order to achieve higher growth rate, environmental problems emerged from economic activities have turned into a controversial issue. The aim of this study is to investigate the effect of financial development on environmental quality in Iran. For this purpose, the statistical data over the period from 1970 to 2011 were used. Also by using the Auto Regression Model Distributed Lag （ARDL）, short-term and long-term relationships among the variables of model were estimated and analyzed. The results show that financial development accelerates the degradation of the environment; however, the increase in trade openness reduces the damage to environment in Iran. Error correction coefficient shows that in each period, 53% of imbalances would be justified and will approach their long-run procedure. Structural stability tests show that the estimated coefficients were stable over the period.     

Exogenous information and input-output updating: An evaluation

Input-output coefficients' intertemporal instability, costs, and time lags involved in the construction of survey-based tables necessitate employment of nonsurvey updating techniques. Analysts, however, may want to include exogenous information in the updating process. The issue, then, is whether this inclusion ameliorates or aggravates the results. This paper attempts to assess the wisdom of incorporating exogenous information into the updating procedure. First, using the naive, RAS, and LaGrangian techniques, the 1966 table of the former Soviet Union was updated to 1972. Next, treating the top 10 percent largest 1972 coefficients as exogenous estimates, the remaining coefficients were updated via the same three methods. Comparison of the results indicates that exogenous determination of the largest coefficients does not change the methods' rankings while yielding substantial improvements in the forecasts. This paper was presented at the Forty-Sixth International Atlantic Economic Conference, Boston, MA, October 8–11, 1998.     

UNIFORM TECHNICAL PROGRESS: CAN IT BE HARMFUL?

Abstract.  In a model incorporating trade in final goods, intermediate goods and capital, we show how 'uniform' technical progress across sectors can lead to immiserization. The condition for immiserizing technical progress crucially depends on the pattern of specialization. Our results tend to hold in a more general specification of the basic structure.     

Natural resource rents and internal conflicts: Can decentralization lift the curse?

We study how natural resource rents affect the risk of internal conflict within countries and how the federal structure of countries influences this relationship. Natural resource abundance may induce excessive rent-seeking and thus increase the risk of internal conflict. Fiscal and political decentralization as an institutional arrangement for rent-sharing and political codetermination of regions within a country may limit the destructive effect of natural resource rents on internal stability. Using cross-country and panel data from more than 90 countries covering the period 1984–2004, we find evidence that natural resource rents indeed increase the risk of internal conflict, but this relationship is significantly mitigated by political decentralization.     

FOREIGN DIRECT INVESTMENT,NON‐TRADED GOODS AND REAL WAGES

Using a three‐sector general equilibrium model with non‐traded goods, we investigate the impact of foreign direct investment on the real wages of skilled and unskilled workers. We show that foreign direct investment increases the real wages of skilled and unskilled workers alike, but widens the gap between the two under plausible conditions.     

Effects of service orientation on job embeddedness in hotel industry

This research aims to develop and analyze a model that depicts work engagement (WE) as a mediator of the relationship between job embeddedness and service orientation. Specifically, the model examines external environmental factors (EEFs) as moderator of the effects of service orientation and job embeddedness in the hospitality industry. All data used for this study were gathered in Iran from hotels frontline employees with a two-weeks’ time lag. These relationships mentioned above were analyzed using AMOS 22.0. It was discovered in the results that WE was indeed a partial mediator and that EEFs indeed moderated the effects of service orientation on job embeddedness with adequate empirical support. The implications of the findings for the managers, the study limitations, and future research recommendations were also discussed.     

A measure of regional influence with the analytic network process

The metropolitan region is commonly defined by a socio-spatial network of urban nodes that are linked in territory and function. Such a network is differentiated by size and dominance of the linked nodes, characterized by physical or virtual flows of a wide-ranging variety. The analytic network process (ANP) is a multi-criteria analytic method that measures the influence or dominance of the nodes in a network with feedback. We illustrate how ANP determines county rank as a measure of influence in a metropolitan statistical area (MSA) defined by its interrelated socio-economic and spatial elements qualitatively and quantitatively. We compare the ANP results to similar measures of regional influence in the literature.