Evaluation of data centre networks and future directions

Traffic forecasts predict a more than threefold increase in the global datacentre workload in coming years, caused by the increasing adoption of cloud and data-intensive applications. Consequently, there has been an unprecedented need for ultra-high throughput and minimal latency. Currently deployed hierarchical architectures using electronic packet switching technologies are costly and energy-inefficient. Very high capacity switches are required to satisfy the enormous bandwidth requirements of cloud datacentres and this limits the overall network scalability. With the maturity of photonic components, turning to optical switching in data centres is a viable option to accommodate greater bandwidth and network flexibility while potentially minimising the latency, cost and power consumption. Various DCN architectures have been proposed to date and this thesis includes a comparative analysis of such electronic and optical topologies to judge their suitability based on network performance parameters and cost/energy effectiveness, while identifying the challenges faced by recent DCN infrastructures. An analytical Layer 2 switching model is introduced that can alleviate the simulation scalability problem and evaluate the performance of the underlying DCN architecture. This model is also used to judge the variation in traffic arrival/offloading at the intermediate queueing stages and the findings are used to derive closed form expressions for traffic arrival rates and delay. The results from the simulated network demonstrate the impact of buffering and versubscription and reveal the potential bottlenecks and network design tradeoffs. TCP traffic forms the bulk of current DCN workload and so the designed network is further modified to include TCP flows generated from a realistic traffic generator for assessing the impact of Layer 4 congestion control on the DCN performance with standard TCP and datacentre specific TCP protocols (DCTCP). Optical DCN architectures mostly concentrate on core-tier switching. However, substantial energy saving is possible by introducing optics in the edge tiers. Hence, a new approach to optical switching is introduced using Optical ToR switches which can offer better delay performance than commodity switches of similiar size, while having far less power dissipation. An all-optical topology has been further outlined for the efficient implementation of the optical switch meeting the future scalability demands

New trends in the economic systems management in the context of modern global challenges (Vol. 2)

Modern global economic challenges caused by the COVID-19 pandemic and various changes in the structure of the world market of goods and services require the developing of new models of economic systems management based on appropriate strategic management methodology, implementation innovation, use of prospects for various risks caused by the pandemic, implementation mechanisms for ensuring the security of economic systems. Ensuring effective management of economic systems in the current global challenges is impossible without the introduction of a new concept of functioning and sustainable development of economic entities. To ensure effective management of economic systems in the context of modern global challenges it is necessary to determine the state of the economic process of entities and explore the impact of risks on current activities, justify and developing a system to overcome negative effects on economic activity and obtain a positive economic result. The effectiveness of developed conceptual provisions to ensure effective management of economic systems is determined by the ability of the management system to withstand the destructive effects of the external environment and due to the strengths to direct the resources of economic entities to maintain the economic process, able ensure to save resources and cover current costs economic entities, etc

Toward the Development of a Church Planting Strategy for the Local Seventh-day Adventist Church in North America

Historically the Seventh-day Adventist Church has been a mission-oriented movement. In harmony with this emphasis church planting is beginning to gain a higher p rio rity in some parts of North America. Very little evidence has been gathered, however, which supports this practice as being an effective means of evangelism. Furthermore, v irtu a lly no guidance has been offered to local SDA churches explaining why church planting should be considered or how it should be accomplished. Empirical data are gathered from various denominations, including the Adventist denomination, regarding the relationship of new church development and membership growth. With positive correlations confirming the place of this practice in a comprehensive plan for evangelism in North America, the report then seeks to develop a strategy which would be helpful for those who will be engaged in this ministry. In order to gain the necessary insights for a holistic and effective approach to church planting two studies are conducted. The first is a description of church growth as recorded in the biblical book of Acts. The second is an analysis and a critique of an actual church-planting experience, the organization of the Spokane South Hill SDA Church, according to church growth lite ra tu re . The principles gained from these two studies provide the framework for a proposed strategy for the placement and development of new congregations in North America. The strategy is designed to be of primary value for those churches which have memberships of 250 or more. The report contends that churches of this size can plant a church by sending a group of dedicated members, approximately fifty , to help form a nucleus for the new church—thereby providing an immediate presence for evangelism and nurture. The strategy is designed to facilitate this process by preparing the mother church theologically and missionally for the eventual church planting. The organizational aspects are then dealt with which lead to the actual formation of the new church. To accentuate the on-going process, flow charts have been prepared to relate the parts to the whole. A theological rationale for this process is presented as an extension of a shared ministry of reconciliation which is also characterized as an incarnational ministry for specific communities and people groups. The joint roles of the clergy and the laity are integrated in both parts of the strategy. Some general recommendations are made which are directed towards creating a more intentional climate for church planting in North America

Developing web-based information systems for emergent organisations through the theory of deferred action: Insights from higher education action research

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This investigation follows a philosophically interpretive approach on how the web developer developed Web-based Information Systems (WBIS) in a continuously changing higher education organisation. The investigation focused on emergence within the organisation and the resultant problems this gives the web developer in developing WBIS. The web developer used an action research methodology to investigate the emergent higher education organisation and its need for web-based aesthetics & internet speed. This approach was designed by the action researcher to assist both the web developer and manager in developing WBIS within emergent organisations. It is also designed to address a number of major constraining factors placed on the web developer. These included: time constraint, web-based aesthetics, internet speed, emergent aspects, methodology issues and accommodating planned organisational change. The interpretation of these constraining factors gained through the theory of deferred action enabled the action researcher to understand, interpret and create associations to explain the WBIS development process. The web developer had to defer the design process at several points because of unexpected events occurring in the organisation and take deferred action. As a result the Kadar Matrix was created and used by the web developer to manage the constraining factors. The Kadar Matrix has extended the theory of deferred action (ToDA) by implementing its constructs in the analytical tool, Kadar Matrix, for WBIS development. This is a modification of theory for practice. The research further identified that deferred action is necessary for the web developer in emergent organisations

Role of informal institutions in Ready-to-Use-Food (RUF) supply chains in Ethiopia

Ready-to-Use food (RUF) product are nutrient dense foods given to individuals that are suffering from acute malnutrition. Currently 5.8 million children suffer from malnutrition in Ethiopia and the timely and efficient delivery of ready-to-use food products has a significant impact on the lives of these children. However, challenges exist in both the local and international production and delivery of RUF products. One of the challenges is the high transaction costs that exist in the supply chains. Transaction costs are the costs associated with searching for information regarding a product or its market, negotiating a deal and enforcing the terms of the deal. In situations where transaction costs are high due to missing or weak markets and institution, people have relied on different mechanisms including social capital (trust and information sharing) to deal with these costs and carry out business and transactions. The purpose of the study is to examine the role institutions, in particular informal institutions, play in addressing these challenges and improving the supply chain for Ready-to-use food products and chickpea marketing (which is a potential ingredient in new RUF formulations). The institutions examined in this study are mainly the non-market institutions like trust and information sharing that build social capital. Data was collected through surveys and interviews from RUF supply chain actors in Ethiopia. These include chickpea producers, RUTF producers, major demanders (humanitarian organizations and governments), transporters, beneficiaries (feeding centers and hospitals). These agents’ use of informal institutions and trust level during transactions with each other is assessed. Interviews with key informants in the value chain in Ethiopia were conducted to further inform the analysis of institutions in supply chain organization and identify areas of high transaction cost. The transaction costs that are present in the supply chains were further identified through focus group discussions with farmers and a farmer survey. Both qualitative and quantitative methods were used to analyze these data. The structure equation model (SEM) was used to quantitatively analyze the data obtained from farmer survey. The study also found that trust between trading partners reduces the time farmers spent negotiating price with buyers. Trust between trading partners also increased the marketed surplus of farmers. Information sharing among trade partners positively affects trust between partners. The study finds that institutions facilitate chickpea marketing through improving trust and information sharing among trading partners. The results indicate that membership in informal institutions strengthens the trust and information sharing between trading partners and this in turn reduces the transaction costs associated with chickpea trade. In addition, the current performance of the RUF supply chain in Ethiopia is found to be relatively efficient with some issues in the availability of local and imported inputs and the failure to comply with quality standards. These results imply that existing, informal institutions in developing countries can be as effective as formal institutions so effort should be put towards their development and improvement. The RUF supply chain can also be further improved by increasing the capacity of local manufacturers to increase production and their capacity to adhere to quality standards. Stabilizing input markets to make inputs to RUF production more consistently available will also improve the production capacity and improve the price and accessibility of RUF products