208,927 research outputs found

    An integrated shipment planning and storage capacity decision under uncertainty: a simulation study

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    Purpose – In transportation and distribution systems, the shipment decisions, fleet capacity, and storage capacity are interrelated in a complex way, especially when the authors take into account uncertainty of the demand rate and shipment lead time. While shipment planning is tactical or operational in nature, increasing storage capacity often requires top management’s authority. The purpose of this paper is to present a new method to integrate both operational and strategic decision parameters, namely shipment planning and storage capacity decision under uncertainty. The ultimate goal is to provide a near optimal solution that leads to a striking balance between the total logistics costs and product availability, critical in maritime logistics of bulk shipment of commodity items. Design/methodology/approach – The authors use simulation as research method. The authors develop a simulation model to investigate the effects of various factors on costs and service levels of a distribution system. The model mimics the transportation and distribution problems of bulk cement in a major cement company in Indonesia consisting of a silo at the port of origin, two silos at two ports of destination, and a number of ships that transport the bulk cement. The authors develop a number of “what-if” scenarios by varying the storage capacity at the port of origin as well as at the ports of destinations, number of ships operated, operating hours of ports, and dispatching rules for the ships. Each scenario is evaluated in terms of costs and service level. A full factorial experiment has been conducted and analysis of variance has been used to analyze the results. Findings – The results suggest that the number of ships deployed, silo capacity, working hours of ports, and the dispatching rules of ships significantly affect both total costs and service level. Interestingly, operating fewer ships enables the company to achieve almost the same service level and gaining substantial cost savings if constraints in other part of the system are alleviated, i.e., storage capacities and working hours of ports are extended. Practical implications – Cost is a competitive factor for bulk items like cement, and thus the proposed scenarios could be implemented by the company to substantially reduce the transportation and distribution costs. Alleviating storage capacity constraint is obviously an idea that needs to be considered when optimizing shipment planning alone could not give significant improvements. Originality/value – Existing research has so far focussed on the optimization of shipment planning/scheduling, and considers shipment planning/scheduling as the objective function while treating the storage capacity as constraints. The simulation model enables “what-if” analyses to be performed and has overcome the difficulties and impracticalities of analytical methods especially when the system incorporates stochastic variables exhibited in the case example. The use of efficient frontier analysis for analyzing the simulation results is a novel idea which has been proven to be effective in screening non-dominated solutions. This has provided the authors with near optimal solutions to trade-off logistics costs and service levels (availability), with minimal experimentation times

    Future consumer mobile phone security: a case study using the data centric security model

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    In the interconnected world that we live in, traditional security barriers are\ud broken down. Developments such as outsourcing, increased usage of mobile\ud devices and wireless networks each cause new security problems.\ud To address the new security threats, a number of solutions have been suggested,\ud mostly aiming at securing data rather than whole systems or networks.\ud However, these visions (such as proposed by the Jericho Forum [9] and IBM\ud [4]) are mostly concerned with large (inter-) enterprise systems. Until now, it is\ud unclear what data-centric security could mean for other systems and environments.\ud One particular category of systems that has been neglected is that of\ud consumer mobile phones. Currently, data security is usually limited to a PIN\ud number on startup and the option to disable wireless connections. The lack of\ud protection does not seem justified, as these devices have steadily increased in\ud capabilities and capacity; they can connect wirelessly to the Internet and have\ud a high risk of being lost or stolen [8]. This not only puts end users at risk, but\ud also their contacts, as phones can contain privacy sensitive data of many others.\ud For example, if birth dates and addresses are kept with the contact records, in\ud many cases a thief will have enough information to impersonate a contact and\ud steal his identity.\ud Could consumer mobile phones benefit from data-centric security? How\ud useful is data-centric security in this context? These are the core questions we\ud will try to address here

    On Shelf Availability: A Literature Review & Conceptual Framework

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    On-Shelf Availability (OSA) is a key performance indicator for the retail industry, greatly impacting profit and customer loyalty. Strong competition in the industry causes retailers and suppliers to put heavy emphasis on improving performance in an effort to satisfy consumers and keep them coming back to their store or product. Over 40 years of research has been done on OSA and its complement, out-of stock (OOS), however very little progress has been made in improving performance in these areas, leading to the belief that gaps in extant research exist. In order to solve the OOS problem, the key drivers of OOS events must first be identified and then addressed. This paper focuses on identifying the drivers of poor OSA performance through a three step process. First, a comprehensive literature review was performed to identify the drivers of OOS addressed in existing literature. Second, interviews with industry professionals revealed potential drivers of poor OSA performance that have been explored at an industry level. Finally, the two lists were examined against each other and the potential drivers identified in the interviews that had yet to be researched were highlighted. This paper gives strategic direction for future research to help solve the OOS dilemma facing manufacturers and retailers today

    Community Trust Stores for Peer-to-Peer e-Commerce Applications

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    CHORUS Deliverable 3.4: Vision Document

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    The goal of the CHORUS Vision Document is to create a high level vision on audio-visual search engines in order to give guidance to the future R&D work in this area and to highlight trends and challenges in this domain. The vision of CHORUS is strongly connected to the CHORUS Roadmap Document (D2.3). A concise document integrating the outcomes of the two deliverables will be prepared for the end of the project (NEM Summit)

    End-to-end resource management for federated delivery of multimedia services

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    Recently, the Internet has become a popular platform for the delivery of multimedia content. Currently, multimedia services are either offered by Over-the-top (OTT) providers or by access ISPs over a managed IP network. As OTT providers offer their content across the best-effort Internet, they cannot offer any Quality of Service (QoS) guarantees to their users. On the other hand, users of managed multimedia services are limited to the relatively small selection of content offered by their own ISP. This article presents a framework that combines the advantages of both existing approaches, by dynamically setting up federations between the stakeholders involved in the content delivery process. Specifically, the framework provides an automated mechanism to set up end-to-end federations for QoS-aware delivery of multimedia content across the Internet. QoS contracts are automatically negotiated between the content provider, its customers, and the intermediary network domains. Additionally, a federated resource reservation algorithm is presented, which allows the framework to identify the optimal set of stakeholders and resources to include within a federation. Its goal is to minimize delivery costs for the content provider, while satisfying customer QoS requirements. Moreover, the presented framework allows intermediary storage sites to be included in these federations, supporting on-the-fly deployment of content caches along the delivery paths. The algorithm was thoroughly evaluated in order to validate our approach and assess the merits of including intermediary storage sites. The results clearly show the benefits of our method, with delivery cost reductions of up to 80 % in the evaluated scenario
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