A comparative literature analysis of definitions for green and sustainable supply chain management

Quantitative models for sustainable supply chain management: Developments and directions

The impact of digitalisation and Industry 4.0 on the ripple effect and disruption risk control analytics in the supply chain (SC) is studied. The research framework combines the results from two is...

The impact of digital technology and Industry 4.0 on the ripple effect and supply chain risk analytics

A fuzzy multi criteria approach for measuring sustainability performance of a supplier based on triple bottom line approach

Over the last decade, the concept of the circular economy has regained attention, especially related to efforts to achieve a more sustainable society. The ‘revival’ of the circular economy has been accompanied by controversies and confusions across different actors in science and practice. With this article we attempt at contributing to advanced clarity in the field and providing a heuristic that is useful in practice. Initially, we take a focus on the historical development of the concept of circular economy and value retention options (ROs) for products and materials aiming for increased circularity. We propose to distinguish three phases in the evolution of the circular economy and argue that the concept – in its dominant framing – is not as new as frequently claimed. Having established this background knowledge, we give insights into ‘how far we are’ globally, with respect to the implementation of circularity, arguing that high levels of circularity have already been reached in different parts of the globe with regard to longer loop value retention options, such as energy recovery and recycling. Subsequently, we show that the confusion surrounding the circular economy is more far reaching. We summarize the divergent perspectives on retention options and unite the most common views a 10R typology. From our analyses, we conclude that policymakers and businesses should focus their efforts on realization of the more desirable, shorter loop retention options, like remanufacturing, refurbishing and repurposing – yet with a view on feasibility and overall system effects. Scholars, on the other hand, should assist the parties contributing to an increased circular economy in practice by taking up a more active role in attaining consensus in conceptualizing the circular economy.

The circular economy: New or Refurbished as CE 3.0? — Exploring Controversies in the Conceptualization of the Circular Economy through a Focus on History and Resource Value Retention Options

In this paper we discuss the problem of locating items within carousel bins in order to minimize the average carousel rotational distance per retrieval. We consider two cases: (1) a single two-dimensional carousel and (2) a group of two one-dimensional carousels. The corresponding problems are formulated as mixed-integer programs. In the second problem we apply concepts from Markovian performance evaluation methods to write the objective functions in a simple linear form. We also define a set of uniqueness constraints that significantly reduces the size of the solution feasibility space. We then apply Benders decomposition algorithm to solve both problems. We develop a closed form solution for the dual subprobem and present numerical results to show the efficiency of the proposed solution methodology.

A Benders decomposition approach to product location in carousel storage systems

Capacity choice or expansion, whether organic or via mergers and acquisitions, creates firms of widely varying scales. The ex-post profitability of such a transformed firm relative to its original size will typically be evaluated on ratio (rate) measures like earnings per share or profits to asset ratio, as such are the only meaningful ways to compare profitability of firms of substantially different sizes. It thus seems desirable that ex-ante capacity selection decisions will also be guided by a ratio objective. We explore capacity choice decisions under demand uncertainty through the ratio measures: (1) Expected "newsvendor" (i.e., single period) costs per unit capacity. (2) Expected (newsvendor) profit per unit of capacity. (3) Expected profit per costs of acquiring capacity. (4) A weighted average of a ratio and non-ratio objectives. We allow the capacity-acquisition costs and capacity's production capability to be general non-linear functions. Cost and profit objectives cease to be equivalent when ratio objectives are involved. We show that cost ratio optimizers will select a larger capacity than absolute cost optimizers, while profit ratio optimizers will select smaller capacities than absolute counterpart. We provide examples which show that the difference in optimal capacities, and the associated difference in objective value can be substantial. We also perform comparative statics analyses of the effect of change in item's shortage cost and of stochastic shifts in demand.

Capacity Selection under Uncertainty with Ratio Objectives

In this article, we study the impact of cross-channel returns on a bricks-and-clicks dual-channel retailer's overall profit, individual channel prices, and individual channel demand under two scenarios: 1) exogenous returns and 2) refund-dependent returns. Our study reveals a number of interesting results. For example, when channel substitutability is high, accepting online purchased returns in the bricks-and-mortar store is likely to drive the in-store price up, despite a drop in the offline demand due to the cannibalization effect. In general, firms should allow cross-channel returns when channel substitutability is high, return handling cost is low, and self-channel returns are not hefty. Unlike the extant literature, we also see that bricks-and-mortar returns impact a multiple-channel retailer's optimal return policy. We are also able to verify that our main findings are fairly consistent under both exogenous and refund-dependent returns scenarios. 

Perils and Merits of Cross-Channel Returns

Reverse auctions are becoming popular for purchasers as a means of lowering acquisition costs. The challenge for purchasers is to assess which approach is best suited to their business situation. In cases where a reverse auction process is chosen, it is also important to identify the structural characteristics of the reverse auction to achieve the best results. This paper provides some insight into the reverse auction dynamics. While some theoretical insight is available in the literature, there has not been any work that explicitly incorporates the bidding process into a reverse auction model. We develop a simulation model that follows the bidding process to determine expected auction outcomes and present the results. We discuss some strategic elements that purchasers should consider in making a reverse auction decision and suggest some reverse auction specifications which might help lower acquisition costs under certain conditions – notably when the number of participants is small.

The impact of supplier numbers and bid decrements on reverse auction outcomes

A strategy suggested recently in the literature for enhancing quality is to use inspection sublots, in which a large production run (batch) is subdivided into smaller portions (sublots) for inspection. In this study we consider a two-stage batch manufacturing process in which the first stage shifts out-of-control at i.i.d. exponential times after starting in control. In any sublot, Stage 1 produces good items before the shift and bad items after. As in a just-in-time environment, a shift's existence is detected when the operator at Stage 2 first encounters a bad item, at which point Stage 1 is re-set to the in-control condition. We use nonlinear programming to develop sublot sizes that maximize the expected number of good items produced by Stage 1. We consider both FIFO and LIFO processing at Stage 2.

Elkafi Hassini

Papers

A Benders decomposition approach to product location in carousel storage systems

Capacity Selection under Uncertainty with Ratio Objectives

Perils and Merits of Cross-Channel Returns

The impact of supplier numbers and bid decrements on reverse auction outcomes

Optimal inspection intervals in a two-stage manufacturing process