A note on ‘A two-level supply chain with consignment stock agreement and stock-dependent demand’

This note points out that the cost functions within Zanoni and Jaber [Zanoni, S. and M. Y. Jaber. 2015. “A Two-level Supply Chain with Consignment Stock Agreement and Stock-dependent Demand.” International Journal of Production Research 53: 3561–3572] might be incorrect due to misuse of demand representation. By incorporating Braglia and Zavanella’s consignment stock model and relaxing the zero-inventory reordering constraint, Zanoni and Jaber made extensions of the integrated vendor–buyer supply chain with stock-dependent demand in Sajadieh, Thorstenson, and Akbari Jokar’s proposed model. However, Sajadieh, Thorstenson, and Akbari Jokar’s model has different scenarios than Braglia and Zavanella’s model, and these inconsistencies cause false formulation in Zanoni and Jaber’s paper. In this note, we first formulate the justified cost functions and then present characteristics of the corrected model.     

A technical note on ‘Analysis of closed loop supply chain using genetic algorithm and particle swarm optimisation’

This study analyses the mixed-integer linear program (MILP) proposed by Kannan et al. [Kannan, G., Noorul Hag, A., and Devika, M., 2009. Analysis of closed loop supply chain using genetic algorithm and particle swarm optimization. International Journal of Production Research, 47 (5), 1175–1200] in their paper entitled ‘Analysis of closed loop supply chain using genetic algorithm and particle swarm optimisation’. Since we find inconsistencies in the model, we propose modifications to rectify the flaws. The revised model is presented and tested using a hypothetical problem.     

A note on ‘A bivariate optimal replacement policy for a repairable system’

An error appearing in equation (3) of Y.L. Zhang (J. Appl. Prob., 1994, 31, 1123–1127) has been pointed out by S.H. Sheu (Eur. J. Oper. Res., 1999, 112, 503–516) and the correct expressions (25)–(27) given accordingly on pp. 510–511. However, the derivation of the key expression (27), the long-run expected loss rate, was not presented. The purpose of this note is threefold. First, since a monotone process (e.g. an arithmetic, geometric, or arithmetic–geometric process) approach, as discussed by K.N.F. Leung (Eng. Optimiz., 2001, 33, 473–484), is considered to be relevant, realistic, and appropriate to the modelling of a deteriorating system maintenance problem, it is worth explicitly developing this expression, which is of benefit to the subsequent studies. Secondly, equation (3) in Zhang (1994) Zhang, Y. L. 1994. A bivariate optimal replacement policy for a repairable system. J. Appl. Prob., 31: 1123–1127. [Crossref], [Web of Science ®] , [Google Scholar] is shown to be fundamentally correct and so it can be viewed as an alternative method of formulating similar bivariate cases. Thirdly, although equations (4) and (5) in Zhang (1994) Zhang, Y. L. 1994. A bivariate optimal replacement policy for a repairable system. J. Appl. Prob., 31: 1123–1127. [Crossref], [Web of Science ®] , [Google Scholar] have been logically and correctly derived, both can be readily reduced to their simplest forms which are derived here.     

Analysis of retailers’ coalition stability for supply chain based on LCS and stable set

To attain the general form of stable coalition structure, this paper addressed the problem of retailers’ coalition stability in a two-stage supply chain consisting of one supplier and multiple retailers. A profit gain function was established via introducing market gain coefficient and coalition cost coefficient for different coalition structures. Based on the function, the profit of each retailer in all kinds of coalition structures was analysed, and the general feature of a stable coalition structure was attained by the largest consistent set method and the stable set method. Furthermore, some insights were obtained. For example, stable coalition structures are equidistributed or approximate equidistributed; with supplier’s cost increasing, the size of the retailers’ coalition increases. Finally, the above conclusions are verified by numerical simulation. The results of this paper provide a reference for retailers’ coalition in a supply chain, such as automobile or Information Technology supply chain.     

A note on ‘trade-off and compatibility between performance: definitions and empirical evidence’

This paper improves on a novel methodology advanced in order to assess deterministically (i.e., precisely) compromises and compatibilities between manufacturing capabilities in individual firms. We extend the original proposal to include more recent theoretical developments arguing that both trade-offs and compatibilities (e.g., cumulative capabilities) can be observed in a relationship between two or more competitive criteria. This means that as opposed to widely-accepted views, trade-offs and compatibilities can be complementary, and not necessarily mutually exclusive, when explaining relationships between various competitive criteria. As such, our improved methodology and rationale can assess the existence of both trade-offs and compatibilities between multiple capabilities utilising a single framework. Opportunities for novel research that uses our methodology are also offered.     

A design model and a production–distribution and inventory planning model in multi-product supply chain networks

Supply chain network (SCN) design implicates decision-making at a strategic level. That includes selecting the right suppliers and determining the number and the location of plants, distribution centres and retailers. An apt design model of the supply chain is imperative for the proper function of the supply chain and consequently for making better operational decisions in an attempt of a continuous improvement. In this paper, we propose two models. The first model is a mixed-integer linear programming model which is concerned with the SCN design problem, whereas the second operational model is a mixed-integer non-linear programming model in respect to the production–distribution and inventory planning problem in a supply chain network. The number of customers and suppliers as well as their demand and capacities are assumed to be known in both models. Two steady-state genetic algorithms were implemented in MATLAB in order to solve both the design and the operational model. The results were compared with GAMS. Some examples were devised in order to demonstrate potential ways of use for the designer of the supply chain network, as well as for the supply chain manager.     

A note on “Modelling an industrial strategy for inventory management in supply chains: the ‘Consignment Stock’ case”

Braglia and Zavanella [2003, Modeling an industrial strategy for inventory management in supply chains: the ‘consignment stock’ care, International Journal of Production Research, 41 (16), 3793–3808] proposed an analytic formulation of consignment stock (CS) policy and made a comparison with Hill [1999, The optimal production and shipment policy for a single-vendor, single-buyer integrated production-inventory problem. International Journal of Production Research, 37 (11), 2463–2473] model. Through dividing per unit holding cost into a financial and a storage one the present note extends their conclusion and shows whether the CS model offers lower costs depends on the comparative result of buyer's and vendor's storage costs.     

Impact of the pull and push‐pull policies on the performance of a three‐stage supply chain

We investigate the performance of two common operating policies (i.e., pull and push‐pull) for a make‐to‐stock product in an un‐capacitated, three‐stage supply chain. The pull policy operates based on periodic orders received from the immediate downstream facility. However, in the push‐pull policy, while processes upstream of the order decoupling point are managed by the push policy, the downstream processes are managed by the pull policy. Simulation experiments are conducted to examine the impact of each operating policy under a variety of experimental conditions, characterised by demand uncertainty and lead‐time variability. Our results indicate that the relative advantage of the two policies is dependent on the type of uncertainty, the level of uncertainty, the inventory control policy and the performance measures of interest. More specifically, while the push‐pull policy results in lower inventory, the pull policy yields a better fill rate. This is in contrast to the notion that the pull policy generally results in superior inventory performance. Our findings suggest that firms should carefully consider the level of uncertainty, the inventory control policy and the performance measures of interest when determining the operating policy.     

Discussion. A reply to ‘A note on a “Change to group technology”’‡

In the industrial field, the idea of subassembly must be distinguished from the subset one, when considering subassemblies as the only subsets in which all parts are stable. An original approach using the disassembly method, the logical reverse chronology of assembly, and the introduction of a mathematical model describing the liaisons allow us to determine the problems related to the automation of assembly sequences. To do so, the modelling of functional liaisons between parts helps to distinguish a simple contact from an attachment, and subsets from subassemblies. Liaisons between components are described by matrices of half degrees of liaison. These liaisons are extracted automatically from a B-rep model of a mechanical product on CAD. Subassemblies are determined automatically just in time during the determination of disassembly sequences. A limitation of this approach is that as soon as a relation is no more orthogonal to the basic referential, a new referential has to be introduced. An expert will choose the best sequence between sequences which were generating.     

When a journal is both at the ‘top’ and the ‘bottom’: the illogicality of conflating citation-based metrics with quality

Scientometrics - The ‘quality’, ‘prestige’, and ‘impact’ of a scholarly journal is largely determined by the number of citations its articles receive....     

Industry 4.0 and resilience in the supply chain: a driver of capability enhancement or capability loss?

The purpose of this research is to develop a better understanding of smart systems and autonomous processes of the Industry 4.0 era. Does the implementation of Industry 4.0 processes and systems expose firms to higher levels of risk in the supply chain through capability loss or does Industry 4.0 spur capability enhancement and thereby increase supply chain resilience? Industry 4.0 is centred on the idea that certain tasks and decisions can be automated through smart systems and autonomous processes. However, is there a risk of losing critical capabilities and the ability to be flexible, agile and resilient to unexpected disruptions in the supply chain? In order to address these questions, this research presents results from semi-structured interviews across multiple industries to provide findings on firms’ uses of smart systems and capability development associated with these systems. Results from this exploratory study may be classified into two primary insights. First, although Industry 4.0 systems are new and, in many cases untested, firms are eager regarding the potential of smart systems to positively impact firm performance and to leverage Industry 4.0 processes for a competitive supply chain advantage. Second, companies did not claim any human capability loss associated with Industry 4.0. In fact, these smart systems may lead to increased supply chain resilience because of capability enhancement and new skill development.     

Performance measures and metrics in logistics and supply chain management: a review of recent literature (1995–2004) for research and applications

Performance measures and metrics are essential for effectively managing logistics operations, particularly in a competitive global economy. The global economy is featured with global operations, outsourcing and supply chain and e-commerce. The real challenge for managers of this new enterprise environment is to develop suitable performance measures and metrics to make right decisions that would contribute to an improved organizational competitiveness. Now the question is whether traditional performance measures can be used and out of them which ones should be given priority for measuring the performance in a new enterprise environment. Some of the traditional measures and metrics may not be suitable for the new environment wherein many activities are not easily identifiable. Measuring intangibles and nonfinancial performance measures pose the greater challenge in the so-called knowledge economy. Nevertheless, measuring them is so critical for the successful operations of companies in this environment. Considering the importance of nonfinancial measures and intangibles, an attempt has been made in this paper to determine the key performance measures and metrics in supply chain and logistics operations. This is based on a literature survey and some of the reported case experiences. Suggestions for future research directions are also indicated.     

Corrigendum of ‘A deterministic model for a repairable item inventory system with a finite repair rate’

The main purpose of this corrigendum is to indicate and rectify the same mistakes made by Schrady (1967 Schrady, D. A. 1967. “A Deterministic Inventory Model for Repairable Items.” Naval Research Logistics Quarterly 14: 391–398.[Crossref] , [Google Scholar]), Nahmias and Rivera (1979 Nahmias, S., and H. Rivera. 1979. “A Deterministic Model for a Repairable Item Inventory System with a Finite Repair Rate.” International Journal of Production Research 17: 215–221.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), and Teunter (2004 Teunter, R. H. 2004. “Lot-Sizing for Inventory Systems with Product Recovery.” Computers and Industrial Engineering 46: 431–441.[Crossref], [Web of Science ®] , [Google Scholar]) in the course of solving their respective models in order that subsequent researchers will not follow the same. To this end, we derive the corresponding correct global-optimal formulae for the substitution-policy model (1,?n), with infinite or finite recovery (or called repair) rate, using differential calculus, as well as providing a closed-form expression to identify the optimal positive integral value of n recovery set-ups. In addition, we also rectify the formulae and solution procedure for numerically solving the constrained non-linear programme.     

Knowledge Transfer and Innovation in Germany and Britain: ‘Intermediate Institution’ Models of Knowledge Transfer under Strain?

This article investigates the links between knowledge transfer activities and innovation performance in Germany and Britain through a detailed comparison of matched samples of electronics production and research establishments in the two countries. In contrast to mature industries such as mechanical engineering, German performance in electronics is not found to be greatly enhanced by the role played by intermediate research institutes in “bridging the gap” between the academic science base and business enterprises.     

‘Uphi?’ ICTs and the mitigation of distance in a South African township

Langa Township, located in Cape Town, South Africa is home to many internal South African migrants and external African immigrants. As a mobile population, many Langa residents have embraced the mobile phone as a means of securing relationships with family members living elsewhere, while also maintaining relationships forged within the township and South Africa in general. Addressing the role of technology in a historical perspective, this article addresses the various ways that mobile phones have both mitigated and exacerbated distance for residents while also acknowledging the advantages and disadvantages of mobile phones for different generations of migrants in the township.     

Distribution of vaccine/antivirals and the ‘least spread line’ in a stratified population

We describe a prioritization scheme for an allocation of a sizeable quantity of vaccine or antivirals in a stratified population. The scheme builds on an optimal strategy for reducing the epidemic''s initial growth rate in a stratified mass-action model. The strategy is tested on the EpiSims network describing interactions and influenza dynamics in the population of Utah, where the stratification we have chosen is by age (0–6, 7–13, 14–18, adults). No prior immunity information is available, thus everyone is assumed to be susceptible—this may be relevant, possibly with the exception of persons over 50, to the 2009 H1N1 influenza outbreak. We have found that the top priority in an allocation of a sizeable quantity of seasonal influenza vaccinations goes to young children (0–6), followed by teens (14–18), then children (7–13), with the adult share being quite low. These results, which rely on the structure of the EpiSims network, are compared with the current influenza vaccination coverage levels in the US population.     

Remote Monitoring of Methane in the Earth’s Atmosphere Based on a Lidar with a Powerful Optical Amplifier

Measurement Techniques - Issues of global control of greenhouse gases are highlighted, and an overview of satellite, airborne and ground-based monitoring methods is given. It is shown that it is...     

A note on a ∼ 1030 cm−1 band in i.r. spectra of zeolite ZSM-5

Crystalline ZSM-5 materials, of different composition, morphology and particle size, were studied with infrared spectroscopy. A frequently observed but never assigned absorption in the 1060–1010 cm⁻¹ region is discussed. It is concluded that the absorption indicates that ZSM-5 framework material in the surface layer of particles with an average particle size larger than 2 microns.     

Reaction on the paper ‘Reliability and validity of findings in ergonomics research’ of Kanis (2013)

In this paper, a reaction on the proposed flowchart of Kanis is given by applying it to a new case. The flowchart seems valuable in starting the discussion on how to improve the reliability and validity in experimental human factors/ergonomics (HF/E) research. However, it is unsure whether it is the golden standard.