Arrival first queueing networks with applications in kanban production systems

In this paper we introduce a new class of queueing networks called {\it arrival first networks}. We characterise its transition rates and derive the relationship between arrival rules, linear partial balance equations, and product form stationary distributions. This model is motivated by production systems operating under a kanban protocol. In contrast with the conventional {\em departure first networks}, where a transition is initiated by service completion of items at the originating nodes that are subsequently routed to the destination nodes (push system), in an arrival first network a transition is initiated by the destination nodes of the items and subsequently those items are processed at and removed from the originating nodes (pull system). These are similar to the push and pull systems in manufacturing systems

Value-driven partner search for <i>Energy from Waste</i> projects

Energy from Waste (EfW) projects require complex value chains to operate effectively. To identify business partners, plant operators need to network with organisations whose strategic objectives are aligned with their own. Supplier organisations need to work out where they fit in the value chain. Our aim is to support people in identifying potential business partners, based on their organisation’s interpretation of value. Value for an organisation should reflect its strategy and may be interpreted using key priorities and KPIs (key performance indicators). KPIs may comprise any or all of knowledge, operational, economic, social and convenience indicators. This paper presents an ontology for modelling and prioritising connections within the business environment, and in the process provides means for defining value and mapping these to corresponding KPIs. The ontology is used to guide the design of a visual representation of the environment to aid partner search

A framework to design reverse logistics operations based on circular economy values

Reverse Logistics (RL) is complex to be managed due to the uncertainty involved e.g. the quality range of products, timing of product returns, and volume of returns. A robust RL design can contribute to increase the effectiveness of RL operations. Therefore, an RL design framework needs to be formalised. Circular economy (CE) focuses on supporting the separation of treatments between technical and biological materials in maximising the design for reuse to return to the biosphere and retain value through innovations across fields. The aim of the research is to develop a new framework to design RL operations based on CE values that can increase the effectiveness and efficiency of RL operations. This research has been conducted through the qualitative research involving cases in product recovery (PR) options that are analysed in-depth. Literature review and interview are the main methods of this research. A test was conducted by interviewing expert and respondents to obtain the expert view and test the research result which is a developed framework to design RL based on CE values. The testing engaged five criteria (usability, feasibility, consistency, effectiveness, and utility). The formal RL design framework, 15 CE values, framework to design RL based on CE values specifically PR options (repair, refurbishment, remanufacturing, and cannibalisation) are main research findings. The research contributes academically to the development of a formal RL design framework and to the identification, reformulation, redefinition, and implementation of CE values. The research can be used as a basis for an effective design of RL that takes into account the economic, environmental, and social impacts. The research can be used as a guideline or an appraisal tool in designing/modifying RL based on CE values that can support the implementation of a single RL operation and also RL based on CE

FROM DOCUMENT MANAGEMENT TO KNOWLEDGE MANAGEMENT

Documents circulating in paper form are increasingly being substituted by itselectronic equivalent in the modern office today so that any stored document can be retrievedwhenever needed later on. The office worker is already burdened with information overload, soeffective and effcient retrieval facilities become an important factor affecting worker productivity. The key thrust of this article is to analyse the benefits and importance of interaction betweendocument management and knowledge management. Information stored in text-based documentsrepresents a valuable repository for both the individual worker and the enterprise as a whole and ithas to be tapped into as part of the knowledge generation process.document management, knowledge management, Information and communication technologies

Mineral Warfare: The Dark Side of Technology and International Mediation

Conflict surrounding the extraction and trade of natural resources is not an uncommon phenomenon. Especially in the case of the Democratic Republic of Congo (DRC), which has historically suffered from the negative impacts of the resource curse since their mineral wealth was first discovered by their Colonial administrators. The importance of Congo’s minerals has fluctuated over the years but has peaked during recent times, as their use in technological advancements are becoming more vital. The global demand for these mineral ores have sky rocketed and consequentially, the largely informal trade has benefitted certain rebel groups, playing a pivotal role in the ongoing violence of Africa’s War. Despite the heightened media attention on the region, the development and enforcement of new international regulations and the creation of industry-led initiatives employed to break the tie between minerals and armed conflict in the DRC, violence is still prevalent. This thesis attempts to understand why this is, arguing that the dominant Western narrative on conflict minerals and its links to the ongoing violence is limited, as it neglects the historical context of the onset of the fighting, as well as the voice of local miners and grassroots organisations in formalisation efforts. I argue that this simplistic account and understanding of the conflict, has impeded current efforts as it overlooks and fails to solve the fundamental and underlying causes of Congo’s conflict