Algorithm portfolios for logistics optimization considering stochastic demands and mobility allowance

The vehicle routing problem with stochastic demand (VRPSD) is a well known NP-hard problem. The uncharacteristic behaviour associated with the problem enhances the computational efforts required to obtain a feasible and near-optimal solution. This paper proposes an algorithm portfolio methodology based on evolutionary algorithms, which takes into account the stochastic nature of customer demand to solve this computationally complex problem. These problems are well known to have computationally complex objective functions, which make their solutions hard to find, particularly when problem instances of large dimensions are considered. Of particular importance in such situations is the timeliness of the solution. For example, Apple was forced to delay their shipments of iPads internationally due to unprecedented demand and issues with their delivery systems in Samsung Electronics and Seiko Epson. Such examples illustrate the importance of stochastic customer demands and the timing of delivery. Moreover, most of the evolutionary algorithms, known for providing computationally efficient solutions, are unable to always provide optimal or near optimal solutions to all the VRPSD instances within allocated time interval. This is due to the characteristic variations in the computational time taken by evolutionary algorithms for same or varying size of the VRPSD instances. Therefore, this paper presents portfolios of different evolutionary algorithms to reduce the computational time taken to resolve the VRPSD. Moreover, an innovative concept of the mobility allowance (MA) in landmoves based on the levy’s distribution function has been introduced to cope with real situations existing in vehicle routing problems. The proposed portfolio approach has been evaluated for the varying instances of the VRPSD. Four of the existing metaheuristics including Genetic Algorithm (GA), Simulated Annealing (SA), Artificial Immune System (AIS), TABU Search (TS) along with new neighbourhood search, are incorporated in the portfolios. Experiments have been performed on varying dimensions of the VRPSD instances to validate the different properties of the algorithm portfolio. An illustrative example is presented to show that the set of metaheuristics allocated to certain number of processors (i.e. algorithm portfolio) performed better than their individual metaheuristics.     

Capabilities as shift parameters for the outsourcing decision

In this paper, we argue that capabilities serve as shift parameters that result in a change in the critical value of asset specificity at which firms switch from in‐sourcing to outsourcing. Capabilities have two effects: they result in a change in firm production costs and in firm governance costs relative to the market. As a result, the frontier at which market governance gives way to firm governance shifts. Three factors that produce such shifts are the value, rarity, and inimitability of capabilities employed in firm processes. Considered as shift parameters, the effect of capabilities integrates seamlessly into transaction costs reasoning and is not a competing view of firm governance. We demonstrate these arguments empirically using a sample of 180 information systems sourcing decisions. Copyright © 2013 John Wiley & Sons, Ltd.     

Diversification strategy,capital structure,and the Asian financial crisis (1997–1998): evidence from Singapore firms

We use agency theory to predict the influence of related and unrelated product diversification on a firm's level of debt financing. Further, we argue that the link between diversification and capital structure is moderated by the environment in which firms operate. Using SAS PROC MIXED, we fit a mixed‐effects model to our unique six‐year longitudinal dataset (1995–2000) of 245 publicly listed Singapore firms. Our data spans the period of the Asian Financial Crisis (1997–1998). We find that firms pursuing unrelated product diversification take on less debt financing in stable environments, but more debt financing in dynamic environments. Using longitudinal structural equation modeling, we find a reciprocal relationship between a firm's product diversification strategy and its debt financing level. Copyright © 2009 John Wiley & Sons, Ltd.     

Does diversity matter? A fresh inquiry into the energy,economy and environment nexus

ABSTRACT

The article extends the literature on the nexus among economy, environment and energy by incorporating an index of electricity generation diversity in production and emission functions. The index is mathematically equivalent to Herfindahl–Hirschman index. The index captures substantial information regarding the ongoing energy transition at the global level. The results obtained through pooled mean group estimation, on a dataset of fairly diversified group of countries, indicate that if diversity index increases by a percentage point, per capita income increases by 2.4% and per capita emissions are reduced by 0.71%. This is against the conventional wisdom in favour of specialization. The study has found some interesting long-run causal pathways. Firstly, the causality runs from diversification to income. Secondly, there is a causality running from electricity consumption to specialization. Thirdly, bi-directional causality runs between emissions and specialization. The results have interesting policy implications. The study supports the growth hypothesis that the electricity consumption drives the economy. As this inevitably increases emissions, a better pathway is through diversification. The fossil fuel intensive pathway may have been the preferred choice in the past for countries with low electricity consumption; the diversified portfolio appears to be prudent in the future.     

STRATEGIC RULES ON SPECULATION IN THE FOREIGN EXCHANGE MARKET

In this article we specify the conditions for profitable speculaion in the foreign exchange market with spot and forward contracts. We derive the unique strategic rules from the initial two‐choice situations in a given environment. Finally, in a more complex structure involving covered arbitrage, speculative profits are computed with iterative plays. JEL classification: F310     

Sales promotions for preorder products: The role of time‐of‐release

Preorder offers are increasingly common for many types of products and services. Sales promotions, such as price discounts and free gifts, are frequently used to raise offer attractiveness and elicit a stronger sales response. Through a series of experiments, we show that a preorder promotion's effectiveness depends on whether it matches the construal level associated with timing of the featured product's release. When a match occurs, it increases consumers’ positive affect leading to higher purchase intention directly or by raising the perceived certainty of new product quality. In addition, we find interesting differences related to promotion type. Specifically, we show that a larger discount promotes low‐level construals, which leads to stronger purchase intentions only when the product is scheduled for near‐future release. Since a gift may elicit either high‐ or low‐level construals, a premium offer of higher perceived value leads to stronger purchase intentions regardless of release timing.