Optimizing replenishment policy in an EPQ-based inventory model with nonconforming items and breakdown

The optimal replenishment policy for an economic production quantity (EPQ)-based inventory model with nonconforming items and breakdown is presented. A real-life production system inevitably generates nonconforming items and has equipment breakdowns owing to process deterioration or other uncontrollable factors. This study addressed these issues in an EPQ-based system to optimize a replenishment policy that minimizes the long-run average cost for the proposed system. Whenever a breakdown occurs, the machine is assumed to immediately be under repair, and an abort/resume inventory control policy is adopted. Under this control policy production of the interrupted lot resumes immediately after the machine is fixed and restored. A mathematical model and a recursive algorithm were used to derive the optimal replenishment policy. A numerical example was used to demonstrate the practical application and better cost efficiency of the proposed policy compared to a breakdown that occurs under a no-resumption policy.     

Terms-of-trade policy in a model with non-produced means of production

Terms-of-trade policies between agriculture and industry are analysed in a two-sector Sraffian model. If both sectors use only produced means of production and labor, it can be shown that an improvement in agriculture's terms of trade always leads to higher profits in agriculture. However, when non-produced means of production are introduced an exogenous increase in the relative price of agricultural commodities may cause the rate of profit in agriculture to increase, remain constant, or even decrease. Two preconditions are identified for the case in which a favorable movement in agriculture's terms of trade decreases that sector's profit rate. First at least one quality of competitively priced land must be scarce relative to the total output required. Second, the initial, economy-wide rate of profit must be positive. Finally, the effect of an input subsidy used in conjunction with terms-of-trade policy is considered. It is shown that under certain conditions reducing the price of production inputs can also cause profits to fall and rents to rise in agriculture.     

International joint venture,commitment and host-country policy in an integrated market

To highlight the importance of bargaining power for both host and foreign partners, we envisage two modes, commitment and no-commitment, respectively, to examine the issue on international joint venture (IJV)’s profit-splitting and optimal host-country policy in an integrated market. With a three-stage Nash bargaining model, it turns out that in an integrated market, tax rate under commitment does not exactly equal zero unless the host partner does not benefit at all in terms of production efficiency by the IJV. Government shall subsidize joint venture while the host partner has more bargaining power than the foreign partner. Furthermore, subsidy is the optimal policy under no-commitment.     

An inventory of simple monetary policy rules in a New Keynesian macroeconomic model

We derive necessary and sufficient conditions for simple monetary policy rules that guarantee equilibrium determinacy in the New Keynesian monetary model. Our modeling framework is derived from a fully specified optimization model that is amenable to analytical characterisation. The monetary rules analyzed are variants of the basic Taylor rules ranging from simple inflation targeting (current, forward, backward) to canonical Taylor rules with and without inertial nominal interest rates. We establish that determinacy obtains for a wide range of policy parameters, especially when the monetary authority targets output and smoothes interest rates. Contrary to other results in the literature, we do not find a case for super-inertial interest rate policy.     

Optimal fiscal policy in the Uzawa-Lucas model with CES production

This paper devises an endogenous growth model with human capital in the Uzawa-Lucas framework in which the average human capital has a positive external effect on the goods sector. Unlike previous works, this paper assumes that output is produced with a CES technology and analyzes the existence, uniqueness, and stability of equilibrium. Also, a fiscal policy is devised that is capable of providing the required incentives to optimize the competitive equilibrium. In order to correct the market failure caused by the externality, the authors introduce a subsidy to human capital and analyze how it can be financed in an optimal way. Some simulation results are presented.     

Modeling a policy making framework for urban sustainability: Incorporating system dynamics into the Ecological Footprint

The Ecological Footprint (EF) is a powerful tool to advance the science of sustainability. However, the static snapshot of EF accounting is not designed to make projections of future sustainability consequences, which fails to elicit policy implications from a dynamic, temporally explicit perspective. This work attempts to incorporate system dynamics (SD) into EF to develop a dynamic EF forecasting framework, and provide a platform to support policy making for urban sustainability improvement. SD is firstly adopted to model the dynamics and interactions of EF driving forces, and then incorporated into the EF framework by correlating system drivers to EF-related consumption categories, embodied EF is finally calculated using the compound-based method. Based on different policy feasibility and sustainability targets, four policy scenarios are designed to explore future sustainability prospects and formulate integrated policies which would attain that sustainability scenario. The modeling procedure is applied to a case study area to illustrate how it works, and policy making for urban sustainability can hopefully be supported using this developed framework in the near future.     

Modeling a policy making framework for urban sustainability: Incorporating system dynamics into the Ecological Footprint

The Ecological Footprint (EF) is a powerful tool to advance the science of sustainability. However, the static snapshot of EF accounting is not designed to make projections of future sustainability consequences, which fails to elicit policy implications from a dynamic, temporally explicit perspective. This work attempts to incorporate system dynamics (SD) into EF to develop a dynamic EF forecasting framework, and provide a platform to support policy making for urban sustainability improvement. SD is firstly adopted to model the dynamics and interactions of EF driving forces, and then incorporated into the EF framework by correlating system drivers to EF-related consumption categories, embodied EF is finally calculated using the compound-based method. Based on different policy feasibility and sustainability targets, four policy scenarios are designed to explore future sustainability prospects and formulate integrated policies which would attain that sustainability scenario. The modeling procedure is applied to a case study area to illustrate how it works, and policy making for urban sustainability can hopefully be supported using this developed framework in the near future.     

Monetary policy of a small open economy in the world production chain

In the world production chain there is a small economy that outsources production to its upstream, sells intermediate goods to its downstream and consumes imported final goods. It is shown that in responding to shocks from demand for intermediate goods, from the wage rate in the upstream and from the currency exchange rate between the upstream and downstream countries, the monetary policy of the small country is insignificant in the sense that any attempt of changing its monetary stance to raise national welfare will be offset by the movements of exchange rates.     

Fiscal policy and the structure of production in a two-sector developing economy

This paper develops a two-sector model of a developing economy and examines the role of the informal sector in limiting the government's ability to increase tax revenues. A key feature is the introduction of auditing of the informal sector and degree of tax enforcement in that sector. We emphasize the interdependence between tax policy and enforcement in achieving a developing economy's fiscal objectives and show that by judicious policy choices the presence of the informal sector need not hinder its ability to raise tax revenues. We supplement the formal analysis with numerical simulations highlighting the contrasting intertemporal tradeoffs implied by higher tax rates and tax-enforcement levels.     

Optimal fiscal policy in an endogenous growth model with public capital: a note

This note presents an investigation of the optimal tax rule in endogenous growth models with public capital. It is presumed that the government levies only an income tax in addition to financing public investment. Furthermore, a household’s saving is deducted from the income tax. We find the optimal tax rule whereby the social optimum is attainable. The manner by which a government imposes a tax on income and administers tax deductions is important for attaining a socially optimal situation.      

An economic manufacturing quantity model with probabilistic deterioration in a production system

This paper develops an economic manufacturing quantity (EMQ) model with deterioration and exponential demand in a production system over a finite time horizon under the effect of inflation and time value of money. The production rate is a dynamic variable (varying with time) in a production system. Due to a long run process, the machinery system is converted from in-control state to out-of-control state which results the production of improper items. The improper items are reworked at a fixed cost to make it as proper. With the increasing value of time, the production of improper item also increases. To reduce the production of the improper items, the systems have to be more reliable and with less amount of failure. In this direction, the model considers that the development cost, production cost, and material cost are dependent on the reliability parameter. The deterioration of the product is considered probabilistic to make the research a more realistic one. By considering the reliability parameter as a decision variable, we try to obtain the associated profit of the system which we have to maximize. To derive the maximization procedure, we use Euler–Lagrange formula from control theory. We outline some numerical examples along with graphical representations and sensitivity analysis to illustrate the model.     

Aggregate fluctuations from independent sectoral shocks: self-organized criticality in a model of production and inventory dynamics

This paper illustrates how fluctuations in aggregate economic activity can result from many small, independent shocks to individual sectors. The effects of the small independent shocks fail to cancel in the aggregate due to the presence of two non-standard assumptions: local interaction between productive units (linked by supply relationships), and non-convex technology. We also argue that neither feature on its own would suffice. In the case of a simple model, we explicitly calculate the distribution of aggregate activity in the limit of an infinite number of independently disturbed sectors.     

Healthcare costs among men with favorable risk prostate cancer managed with observation strategies versus immediate treatment in an integrated healthcare system

Objective: This study explored short-term healthcare costs of men managed with observation strategies (OBS) vs immediate treatment (IMT) for favorable risk prostate cancer (PCa) from the Geisinger Health System, a single integrated health system in Pennsylvania, as evidence from the community setting is limited.

Methods: A retrospective cohort study was conducted using electronic health records from men aged ≥40 years diagnosed with favorable risk PCa (T1 or 2, PSA ≤15?ng/mL, Gleason ≤7 [3?+?4]) between January 2005 and October 2013. Prostate-specific healthcare costs were compared between the OBS and IMT cohorts in men with ≥3 years of follow-up and available linked claims data. Sub-group analyses focused on those men with low-risk PCa (T1-2a, PSA ≤10?ng/mL, Gleason ≤6). Sensitivity analysis stratified the study sample in three cohorts: OBS, switched from OBS to definitive treatment (OBS switch), and IMT.

Results: A total of 352 patients were included (OBS?=?70 and IMT?=?282). Compared with IMT, OBS resulted in significantly lower cumulative PCa-related healthcare costs for the first 3 years ($15,785 vs $23,177; p-value <.001). The main cost drivers were outpatient procedures. The OBS cohort had the lowest incremental PCa-related healthcare costs in the first 3 years (OBS: $5,011 vs OBS switch: $26,040, net cost savings?=?$21,029, p?p?Conclusions: In favorable risk PCa, half of the patients who initially chose OBS eventually underwent treatment after their PCa diagnosis. As expected, OBS was associated with reduced disease management costs compared with IMT.     

Fiscal policy in an endogenous-growth model with public investment: A note

This note extends the basic endogenous-growth model by Barro [Journal of Political Economy (1990) 98: S103–S125]. It is supposed that the government pays lump-sum transfers to the representative household or levies a lump-sum tax, besides financing public investment. Growth and welfare effects of fiscal policy are studied for the competitive economy and the growth rate of the social optimum is compared with the one of the competitive economy.     

Equilibrium cycles in an overlapping generations economy with production

Perfect foresight equilibrium trajectories of an overlapping generations model with production may include stable or unstable invariant closed curves. These orbits are detected using the Hopf bifurcation theorem, where the parameter of bifurcation is purely technological. The paper also proves that there is a stabilization policy that completely eliminates the cycle. Finally, using a C.E.S. production function, it is shown that the range of values of the elasticity of substitution between capital and labor for which cycles may exist is bounded above.     

Dynamic inefficiency in an overlapping generations economy with production

Reichlin [Equilibrium cycles in an overlapping generations economy with production, J. Econ. Theory 40 (1986) 89-102] has shown in an OLG model with productive capital that whenever the steady state is locally indeterminate and undergoes a Hopf bifurcation, it is Pareto-optimal. While these results were established under the assumption of Leontief technology, the author has partially extended them to show that the Hopf bifurcation is robust with respect to the introduction of capital-labor substitution. In this note, we prove that the Pareto-optimality of the steady state does not extend to technologies with capital-labor substitution. When the steady state is a sink or undergoes a Hopf bifurcation, it is characterized by over-accumulation with respect to the Golden Rule—the interest rate is negative—hence not Pareto-optimal. Most importantly, it follows that stabilization policies targeting the steady state leave room for welfare losses associated with productive inefficiency, apart from the very special case of Leontief technology.     

Discretionary policy in a monetary union with sovereign debt

This paper examines the interactions between multiple national fiscal policymakers and a single monetary policy maker in response to shocks to government debt in some or all of the countries of a monetary union. We assume that national governments respond to excess debt in an optimal manner, but that they do not have access to a commitment technology. This implies that national fiscal policy gradually reduces debt: the lack of a commitment technology precludes a random walk in steady-state debt, but the need to maintain national competitiveness avoids excessively rapid debt reduction. If the central bank can commit, it adjusts its policies only slightly in response to higher debt, allowing national fiscal policy to undertake most of the adjustment. However, if it cannot commit, then optimal monetary policy involves using interest rates to rapidly reduce debt, with significant welfare costs. We show that in these circumstances the central bank would do better to ignore national fiscal policies in formulating its policy.     

Identification of development indicators in tropical mountainous regions and some implications for natural resource policy designs: an integrated community case study

In tropical and subtropical countries a social gradient can be observed in mountainous regions between small-scale farmers on fragile ecosystems associated with human poverty, and the fertile plains and broad valleys with large-scale cash crop productions and industrial centers associated with relative economic welfare. Sustainable community development paths have to be identified in these less privileged regions. The objective of this study was to make a contribution for defining and assessing development indicators at community level, including ecological, economic and social dimensions, to elicit the conflicting objectives in development and to discuss some practical implications. The study was performed in a typical watershed in central Honduras and special attention was given to autochthonous and qualitative indicators for development. Using the pressure-state-response model as a framework, a series of indicators were identified and assessed, which were also used by the local population and grouped into landscape structure, soil fertility, water availability and quality, production system and extractive activities, economic and social performance, and institutions. The development path in this specific case illustrated the transition from an expansive forest conversion agriculture to an intensified and diversified agriculture. This was made possible through technology transfer and improved market access. However, this development path, while increasing economic welfare, generated increasing negative environmental impacts caused by pesticide residues, soil erosion and less regular water supply. As the watershed carrying capacity for traditional shifting cultivation (used as a system indicator) reached its ecological limit, new sustainable development strategies had to be identified. The implications of the study for policy design are that tools need to be provided for natural and environmental resource monitoring, which may consist of sustainability goal definitions, a minimal set of indicators and simple maps for planning land use at local level.     

Welfare effects of monetary policy in an economy with vertical production and trade: An analysis based on the perspective of local currency pricing

By incorporating the factor of firms' asymmetric price setting behavior into the two-country model with vertical production and trade, we analyze how one country's monetary policy affects the welfare of both countries. We show that an expansionary monetary policy has (i) a beggar-thyself effect if the ratio of the non-expanding country's intermediate goods firms that set their export prices in the local currency is significantly low and (ii) a prosper-thy-neighbor effect in our model regardless of the ratio of either country's intermediate goods firms that set their export prices in the local currency.