A multi-objective and multi-period optimization model for urban healthcare waste’s reverse logistics network design

Various types of healthcare waste (or medical waste) generated by urban healthcare activities have increased due to the expansion of urban population and medical needs. As healthcare wastes are harmful to both the environment and human health, managing medical waste is becoming progressively more important. Constructing an optimized medical waste recycling network is one of the key problems in the management of urban healthcare waste. This paper conducts a two-stage reverse logistics network design for urban healthcare waste. The first stage involves the prediction of the amount of medical waste. Based on the Grey GM(1,1) prediction model, the amount of medical waste in multi-period of the target hospitals is predicted. In the second stage, a multi-objective model aimed at minimizing operating costs and minimizing environmental impact is developed for facilities allocation decisions, which include the configuration of key facilities such as hospitals, collection centers, transshipment centers, processing centers, and disposal sites, as well as medical waste flow control among facilities. A dynamic approach for the healthcare waste reverse logistics network is constructed by combining the Grey GM(1,1) prediction method with multi-objective optimization model. Sensitivity analysis of key parameters has been performed to analyze their impact on network performance. Some insightful management practices have been revealed.

     

A multiple buyer – supplier relationship in the context of SMEs’ digital supply chain management*

Abstract

By underlining the relevance of the use of ICTs, knowledge sharing and electronic markets for SMEs, it emerges the need for stimulating a debate on digitisation process of supply chain management (SCM). Electronic infrastructure in the service sector are reducing each kind of cost and improving multiply buyer–supplier relationships, facilitating negotiations and transactions. However, since the coordination costs are still high, the use of ICTs is limited. This phenomenon thus attracts the interests of scholars and practitioners. Although it still needs to further investigate. Especially, the optimal use of ICTs within SMEs’ SCM have not been studied yet. Therefore, by leveraging on four proxies: ICTs specialised human resources, knowledge sharing activities, buyer–supplier relationships, adoption of electronic markets this optimal was analysed via structural equation modelling based on a sample of 1254 SMEs operating in the service sector in Italy.     

A three-stage supply chain scheduling problem based on the nursing assistants’ daily work in a hospital

Journal of Combinatorial Optimization - In a hospital, the nursing assistants in wards are always responsible for delivering patients to do some medical examinations, and the nursing assistants in...     

A critical review on supply chain risk – Definition,measure and modeling

Economic systems are increasingly prone to complexity and uncertainty. Therefore, making well-informed decisions requires risk analysis, control and mitigation. In some areas such as finance, insurance, crisis management and health care, the importance of considering risk is largely acknowledged and well-elaborated, yet rather heterogeneous concepts and approaches for risk management have been developed. The increased frequency and the severe consequences of past supply chain disruptions have resulted in an increasing interest in risk. This development has led to the adoption of the risk concepts, terminologies and methods from related fields. In this paper, existing approaches for quantitative supply chain risk management are reviewed by setting the focus on the definition of supply chain risk and related concepts.     

Transmission of a supplier’s disruption risk along the supply chain: a further investigation of the Chinese automotive industry

This paper primarily explores whether the transmission of a supplier’s disruption risk along the supply chain exists using a quantitative survey conducted in 31 Chinese automotive-related companies. Two downstream supply chain members are considered: manufacturer and distributor. Structural equation modelling is used. We find that both manufacturer and distributor can be affected by supplier disruptions. In particular, distributors are impacted in two ways: indirectly and directly. On the one hand, indirect transmission of the supplier’s disruption risk to distributors is assumed to be an outcome of interrupted material flows for the production and sales of whole vehicles along the supply chain. Domino effect is used to explain this phenomenon. On the other hand, direct transmission is presumed to originate from the direct business contact between the supplier and distributors in terms of automotive spare parts. Based on primary findings, this paper further investigates strategies used by manufacturers and distributors to mitigate the adverse effects of supplier disruptions through semi-structured interviews. Theoretical and practical implications, as well as limitations, are discussed.     

A note on “Coordinating a supply chain for deteriorating items with a revenue sharing and cooperative investment contract”

In this short note, we first improve the proof in Zhang et al. [1] to show the strict concavity of the unit time total profit of the whole supply chain with respect to preservation technology investment without approximation. We then generalize the model of Zhang et al. [1] to a broader class of market demand functions. Additionally, theoretical results are provided to illustrate the features of the proposed model.     

Organizing for strategic management— A conceptual model

Managing the strategic problems is a complex process. In order to organize this process efficiently in one's own company it is necessary to understand and be able to communicate the basic factors involved. In the author's view there is a need to compile into a model concepts, relations and organizational principles of major importance to successful strategic planning. This article is based on the author's analysis of current literature and his own practical experience in Scandinavia. The article presents a conceptual model for strategic management including the planning process as well as the execution of strategic decisions. This model is related to basic organizational principles and the methodology used in project management.     

Milton keynes: A model for regenerating our cities?

Milton Keynes is one of the most succesful of Britain's new towns. With new towns such as Peterborough and Telford, this can be seen as the latest stage of the New Town Movement which started at the end of World War II. Of these new towns, Milton Keynes is the largest and the most ambitious in its objectives. The problems facing the United Kingdom today are very much greater than when Milton Keynes was first started but, because of a flexible planning approach, the Development Corporation has responded to these changes and has established policies to assist in solving these problems. The key to this success is a more flexible and effective manufacturing base. Today we face unprecedented changes, unique in our history. Although manufacturing and services will provide the wealth to solve these problems, we will only succeed through co-operation between the private sector and local and national government. A study of Milton Keynes, its growth, objectives, successes and failures could provide a useful model for our future planning.     

A generalization of Macula’s disjunct matrices

As a generalization of the novel construction of disjunct matrices by Macula (Discrete Math. 162:311–312, 1996), we construct a new family of disjunct matrices and discuss its error-tolerant property.     

Creating a manufacturing environment that is in harmony with the market—the ‘how’ of supply chain management

The inherent instabilityof complex supplychains is well understood and documented; the potential benefits of taking time out of the chain in terms of reduced inventory and lower operating costs are clearly substantial. There is now a broad community of managers and practitioners who know ‘what’ in principle needs to be done. The issue for all is ‘how’ to go about it for their particular business. This paper builds on an organizational trade-off model through which logistics moderates the conflicting demands and culture of manufacturing on the one hand and marketing on the other. The paper introduces three practical techniques for securing the benefits of supply chain management: time-based simulation; cost-to-serve; and piloting change. Used together these methodologies can deliver breakthrough in supply chain effectiveness.     

A Study of Typology of Teacher’s Questions

This study invested the typology of teacher’s questions as well as its functions in teaching. Teacher’s questions are widely acknowledged as a valuable instrumental strategy,improved classroom questioning strategies may contribute to the development of students’ higher cognitive-thinking skills,asking the right questions appears to enhance the student learning.     

Testing Klein and Sorra’s innovation implementation model: An empirical examination

Despite a substantial volume of research activities on innovation implementation [Holahan, P.J., Aronson, Z.H., Jurkat, M.P., Schoorman, F.D., 2004. Implementing computer technology: a multiorganizational test of Klein and Sorra’s model. Journal of Engineering and Technology Management 21 (1), 31–50; Klein, K.J., Sorra, J.S., 1996. The challenge of innovation implementation. Academy of Management Review 21 (4), 1055–1080; Kwon, T.H., Zmud, R.W., 1987. Unifying the fragmented models of information systems implementation. In: Hirschheim, B.R. (Ed.), Critical Issues in Information Systems Research. John Wiley and Sons Ltd., New York, pp. 227–252], implementation outcomes continue to disappoint—particularly those related to large-scale information systems (ISs) implementation projects [Aiman-Smith, L., Green, S.G., 2002. Implementing new manufacturing technology: the related effects of technology characteristics and user learning activities. Academy of Management Journal 45 (2), 421–430; The Standish Group International Inc., 1995. Chaos (Application Project Failure and Success). Access http://www.standishgroup.com/chaos.html; Whittaker, B., 1999. What went wrong? Unsuccessful information technology projects. Information Management & Computer Security 7 (1), 23–29]. In 1996, Klein and Sorra introduced a promising model that posited key determinants of implementation effectiveness. In this paper we present new validated construct measures, and then test the Klein and Sorra model using a survey of 209 employees in seven organizations. Our results demonstrate that IS implementation effectiveness is influenced directly and indirectly by innovation-values fit, and indirectly by implementation climate.     

A Nerlovian cost inefficiency two-stage DEA model for modeling banks’ production process: Evidence from the Turkish banking system

By developing a two-stage model the paper examines the cost inefficiency levels of Turkish banks during the period from 2007 to 2016. Using the notion of Koopmans input efficiency we deconstruct the estimated Nerlovian cost inefficiency to the sum of slack-based allocative and technical inefficiency levels. Alongside the traditional inputs, intermediates and outputs used to model banks’ performance measure we additionally use their labor education quality factor as a non-discretionary input. This allows us to model how human capital factors affect a bank's revenue generation stage. Our findings suggest that cost inefficiency levels are driven mainly by a bank's ability to control its allocative inefficiency levels. The empirical evidence also shows that foreign banks perform better, suggesting that bank ownership structures matter when measuring cost performance. Finally, it is evident that the Global Financial Crisis (GFC) had a negative effect on banks’ ability to minimize their cost inefficiency levels. However, the post-crisis findings demonstrate that Turkish banks have started to recover from its negative effects, mainly by improving their allocative performance.     

Customer complementarity in the digital space: Exploring Amazon’s business model diversification

In spite of the striking evidence that many firms run multiple business models, scholars and practitioners still lack a comprehensive understanding about business model portfolio dynamics, particularly when this happens in the digital space. Prior research on business model diversification tends to focus on supply-side complementarities, such as a firm's synergies among resources and capabilities. Yet, the demand-side with its customer complementarities remains theoretically and empirically underexplored, despite offering interesting opportunities for firms' competitive advantage. By developing a qualitative, longitudinal (1995–2018) analysis of the various business models developed by Amazon.com, we identify and map how customer complementarities—network effects and one-stop shop effects—can support firm growth and competitive advantage, particularly in the digital space. We identify what we term the ‘integrative business model,’ defined as the business model in a portfolio exhibiting the most (predominantly positive) customer complementarities with other business models. We propose mechanisms for the integrative business model to contribute to sustainable competitive advantage via a causal loop diagram and discuss implications for theory and practice.     

How does consumer age affect the desire for new products and brands? A multi-group causal analysis

Marketing lacks comprehension on the increasingly important segment of mature consumers in regard to their behavior and respective reasons for certain behavior. This study on the desire for alternative products or brands within the domain of fast moving consumer goods was capable of verifying differences among age-groups. While the keenness for cross-buying increases with age, the desire for switching to other familiar brands than the one usually purchased, and the desire for switching to new brand alternatives decrease with age; Thus indicating age-patterns in product category-specific innovativeness and variety seeking. The study also considers a wide range of behavioral determinants such as product satisfaction, product involvement, category experience, perceived purchase risk etc. mediating the effect of age on these desires, giving a fairly good picture of the unveiled causes for the age group differences. Furthermore, the issue of age potentially operating as a moderating variable on the effects of the behavioral determinants on the desires for product and brand alternatives found consideration in this study, but was proven to be of marginal relevance.     

A quadratic lower bound for Rocchio’s similarity-based relevance feedback algorithm with a fixed query updating factor

Rocchio’s similarity-based relevance feedback algorithm, one of the most important query reformation methods in information retrieval, is essentially an adaptive supervised learning algorithm from examples. In practice, Rocchio’s algorithm often uses a fixed query updating factor. When this is the case, we strengthen the linear Ω(n) lower bound obtained by Chen and Zhu (Inf. Retr. 5:61–86, 2002) and prove that Rocchio’s algorithm makes Ω(k(n−k)) mistakes in searching for a collection of documents represented by a monotone disjunction of k relevant features over the n-dimensional binary vector space {0,1} ⁿ , when the inner product similarity measure is used. A quadratic lower bound is obtained when k is linearly proportional to n. We also prove an O(k(n−k)³) upper bound for Rocchio’s algorithm with the inner product similarity measure in searching for such a collection of documents with a constant query updating factor and a zero classification threshold.     

A new model for successful management of engineering design firms — “superpositioning”

A SuperPositioning model for successful management of engineering design firms is discussed which allows firms to be categorized within a matrix bounded by two primary drivers, their engineering Design Techology (how they do their work) and their Values (the primary reward thrusts or motivations of the owners). Technologies are separated into Strong Idea (Brains), Strong Service (Gray Hair) and Strong Delivery (Routine Procedure). Values are divided between Practice Centered Business and Business Centered Practice.The firm's Design Technology affects the optimal way it should handle Project Design, Project Decision Making, Middle and Lower Level Staffing, Markets, What it Sells, What it Can Charge, and Best Management Style. Its choice of Values impacts the Organization Structure, Organization Decision-Making, Staffing at the Top, How it Markets, Best Clients, Marketing Organization, Profit Strategy, Reward and Management Style. Firms that optimize their strategies for these elements to match their choice of drivers are observed to perform better for their clients and in terms of their owner's satisfaction.     

A new model for examining the leader – member exchange (LMX) theory

The theory of leader?–?member exchange (LMX) is re-examined. The concepts of social and economic exchange misused in previous research are clarified. A model that describes the exchange relationships between manager and subordinates is presented. The model challenges the well-accepted positive relationship between high quality of LMXs and organizational performance in previous studies by pointing out that the relationship may lead to negative results. New research propositions based upon the model are offered to encourage further research efforts.     

A note on ‘a strategy for optimal equipment replacement’

A recent article in this journal outlined strategies for the replacement of components and sub-assemblies when considering hazard rates and for capital intensive equipment when considering influences such as increasing maintenance costs, inflation, discount rates, and depreciation. We expand upon this second analysis, concerning the replacement of capital intensive equipment with net present value (NPV) analysis, by guaranteeing that all feasible options are evaluated when determining the optimal strategy. This requires assumptions about future challengers (potential replacement equipment over time) and the time horizon for analysis. We illustrate different solution approaches based on the given assumptions.