3,793 research outputs found
A Continuum,O(N) Monte-Carlo algorithm for charged particles
We introduce a Monte-Carlo algorithm for the simulation of charged particles
moving in the continuum. Electrostatic interactions are not instantaneous as in
conventional approaches, but are mediated by a constrained, diffusing electric
field on an interpolating lattice. We discuss the theoretical justifications of
the algorithm and show that it efficiently equilibrates model polyelectrolytes
and polar fluids. In order to reduce lattice artifacts that arise from the
interpolation of charges to the grid we implement a local, dynamic subtraction
algorithm. This dynamic scheme is completely general and can also be used with
other Coulomb codes, such as multigrid based methods
Consumer behaviour and order fulfilment in online retailing â a systematic review
This paper provides a systematic review of consumer behaviour and order fulfilment in online retailing. The objective of this review is threefold: first, to identify elements of orderâfulfilment operations that are relevant to online consumer behaviour (purchase, repurchase, product return); second, to understand the relationship between orderâfulfilment performance and consumer behaviour; and third, to inspire future research on developing consumer service strategies that takes account of these behavioural responses to orderâfulfilment performance outcomes. The paper is based on a systematic review of literature on online consumer behaviour and orderâfulfilment operations, mainly in the fields of marketing and operations, published in international peerâreviewed journals between 2000 and September 2015. This study indicates that the current literature on online consumer behaviour focuses mainly on the use of marketing tools to improve consumer service levels. Very little research has been conducted on the use of consumer service instruments to steer consumer behaviour or, consequently, to manage related orderâfulfilment activities better. The study culminates in a framework that encompasses elements of orderâfulfilment operations and their relationship to online consumer behaviour. This paper is the first comprehensive review of online consumer behaviour that takes aspects of orderâfulfilment operations into account from both marketing and operations perspectives
Preparing for new competitive challenges: special issue on the 24th annual IPSERA conference
The 24st IPSERA conference in Amsterdam addressed the various new competitive challenges organizations face now that business environments are changing. While we can observe an increased role of - but also an increased concentration in - logistic services and IT services acting as a bonding agent of the various business processes, we also see an increased specialisation among suppliers, resulting in roles like capacity supplier, co-maker and broker. In terms of Systems Thinking: the subsystem of âSuppliersâ is breaking up into three sub-systems with distinctive different characteristics,
and the traditional sub-system âPurchasingâ has transformed into an aspect-system connecting or
involving all other sub-systems, while similarly, âLogisticsâ and âITâ have developed into intertwined
aspect-systems, being part of each and every sub-system. These transformations have increased managerial complexity, greatly influencing the purchasing and supply chain functions within firms. The seven papers selected from the conference examine seven aspects of those changes in detail and elaborate on the role of the PSM field in this process: PSM answers to challenges by providing answers on how to move forward in practice
Ecologically friendly sourcing in developing countries: a non-food case study
The purpose of this paper is to investigate how nearby sourcing versus long-distance sourcing affects the ecological friendliness - operationalized in terms of energy efficiency - of a supply chain for a non-food item in a developing country. Using case research, we show that the average energy needed to supply a pair of imported shoes to a retailer in Morocco is less than the average energy needed to supply a pair of locally produced shoes. These findings highlight the need to assess the true total energy effects of nearby sourcing versus long-distance sourcing since the outcomes of such assessments may be more complicated than they appear upon first glance, particularly in developing countries
Performance management practices in humanitarian organisations
Purpose â We examine how design and implementation practices for supply chain performance management that have proven successful in commercial organisations apply to Humanitarian Organisations (HOs) to guide the process of designing and implementing performance management in humanitarian organisations.
Design/methodology/approach â We identify from the literature 10 successful practices regarding the design and implementation of supply chain performance management in commercial businesses. We apply these, using action research over a four-year period, at MĂ©decins sans FrontiĂšres (MSF) Belgium and draw conclusions from this.
Findings â We find that tools and techniques, such as workshops and technical sheets, are essential in designing and implementing supply chain performance measurement projects at HOs. Furthermore, making a link to an IT project is crucial when implementing performance measurement systems at HOs. Overall, our case study shows that performance management practices used in business can be applied and are relevant for humanitarian supply chains.
Originality/value â Previous research has argued that there are few empirical studies in the domain of performance management at humanitarian organisations. To the best of our knowledge, this paper is the first to provide a longitudinal understanding of the design and implementation of supply chain performance measurement at HOs
Individual goals and social preferences in operational decisions
Purpose: The purpose of this paper is to develop propositions explaining the influence of individual goals and social preferences on human decision making in transport planning. The aim is to understand which individual goals and social preferences planners pursue and how these influence plannersâ decisions.
Design/methodology/approach: Propositions are developed based on investigation of decision making of transport planners in a Dutch logistics service provider using multiple data collection methods.
Findings: The study shows how decision making of transport planners is motivated by individual goals as well as social preferences for reciprocity and group identity.
Research limitations/implications: Further research including transaction data analysis is needed to triangulate findings and to strengthen conclusions. Propositions are developed to be tested in future research.
Practical implications: Results suggest that efforts to guide planners in their decision making should go beyond traditional (monetary) incentives and consider their individual goals and social preferences. Moreover, this study provides insight into why transport planners deviate from desired behaviour.
Originality/value: While individual decision making plays an essential role in operational planning, the factors influencing how individuals make operational planning decisions are not fully understood
Reactive oxygen species accelerate de novo acquisition of antibiotic resistance in E. coli
Reactive oxygen species (ROS) produced as a secondary effect of bactericidal antibiotics are hypothesized to play a role in killing bacteria. If correct, ROS may play a role in development of de novo resistance. Here we report that single-gene knockout strains with reduced ROS scavenging exhibited enhanced ROS accumulation and more rapid acquisition of resistance when exposed to sublethal levels of bactericidal antibiotics. Consistent with this observation, the ROS scavenger thiourea in the medium decelerated resistance development. Thiourea downregulated the transcriptional level of error-prone DNA polymerase and DNA glycosylase MutM, which counters the incorporation and accumulation of 8-hydroxy-2âČ-deoxyguanosine (8-HOdG) in the genome. The level of 8-HOdG significantly increased following incubation with bactericidal antibiotics but decreased after treatment with the ROS scavenger thiourea. These observations suggest that in E. coli sublethal levels of ROS stimulate de novo development of resistance, providing a mechanistic basis for hormetic responses induced by antibiotics.</p
Humanitarian-business partnerships in managing humanitarian logistics
Purpose: The aim of this article is to conduct a systematic literature review to understand the state of the art of partnerships between humanitarian organizations and business corporations in managing humanitarian logistics.
Design/methodology/approach: A systematic literature review is conducted based on the steps proposed by Denyer and Tranfield (2009). The Context-Intervention-Mechanism- Outcome (CIMO) logic is applied to identify the state of the art of partnerships between humanitarian organizations and business corporations in humanitarian logistics. Thirty-six papers related to the topic are extracted from recognized journal databases and then classified into four categories based on the CIMO logic: situational context, intervention factors, mechanisms, and outcomes.
Findings: The study shows that while the context and mechanisms for developing crosssector partnerships between the humanitarian and the business sector have been examined and illuminated by many researchers, additional research (in particular, empirical studies) is needed to measure outcomes as well as the contributions of partnerships to the performance of humanitarian logistics. In addition to synthesizing the literature in this area this study also presents challenges of such partnerships.
Academic and practical implications: The study improves the understanding of the state of cross-sector partnerships in humanitarian logistics as well as identifies opportunities for future research in this area. The study provides reasons and motives of initiating humanitarian-business partnerships in humanitarian logistics as well as their mechanisms and potential outcomes. This may help in developing successful logistics partnerships with each other.
Originality/value: This is the first systematic literature review to examine the nature of partnerships between humanitarian organizations and business corporations in humanitarian logistics using CIMO logic
Coideal Quantum Affine Algebra and Boundary Scattering of the Deformed Hubbard Chain
We consider boundary scattering for a semi-infinite one-dimensional deformed
Hubbard chain with boundary conditions of the same type as for the Y=0 giant
graviton in the AdS/CFT correspondence. We show that the recently constructed
quantum affine algebra of the deformed Hubbard chain has a coideal subalgebra
which is consistent with the reflection (boundary Yang-Baxter) equation. We
derive the corresponding reflection matrix and furthermore show that the
aforementioned algebra in the rational limit specializes to the (generalized)
twisted Yangian of the Y=0 giant graviton.Comment: 21 page. v2: minor correction
A simulation-optimization approach for a service-constrained multi-echelon distribution network
Academic research on (s,S) inventory policies for multi-echelon distribution networks with deterministic lead times, backordering, and fill rate constraints is limited. Inspired by a real-life Dutch food retail case we develop a simulation-optimization approach to optimize (s,S) inventory policies in such a setting. We compare the performance of a Nested Bisection Search (NBS) and a novel Scatter Search (SS) metaheuristic using 1280 instances from literature and we derive managerial implications from a real-life case. Results show that the SS outperforms the NBS on solution quality. Additionally, supply chain costs can be saved by allowing lower fill rates at upstream echelons
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