Scalability and robustness of a market-based network resource allocation system

In this paper, we consider issues related to scalability and robustness in designing a market-based multi-agent system that allocates bandwidth in a communications network. Specifically, an empirical evaluation is carried out to assess the system performance under a variety of design configurations in order to provide an insight into network deployment issues. This extends our previous work in which we developed an application that makes use of market-based software agents that compete in decentralised marketplaces to buy and sell bandwidth resources. Our new results show that given a light to moderate network traffic load, partitioning the network into a few regions, each with a separate market server, gives a higher call success rate than by using a single market. Moreover, a trade-off in the number of regions was also noted between the average call success rate and the number of messages received per market server. Finally, given the possibility of market failures, we observe that the average call success rates increase with an increasing number of markets until a maximum is reached

Sustainability as a Small Business Competitive Strategy

In our global village, sustainability has been an important topic for all countries, and small businesses can create a competitive advantage through developing sustainability strategies. This conceptual article extends the current literature by presenting the case for small businesses to become integrated in the surrounding community and to make sustainability a strategic long-term competitive advantage and a critical co-producer of its long-term success. Implications and the need for further research are discussed

Sustainability as a Small Business Competitive Strategy

In our global village, sustainability has been an important topic for all countries, and small businesses can create a competitive advantage through developing sustainability strategies. This conceptual article extends the current literature by presenting the case for small businesses to become integrated in the surrounding community and to make sustainability a strategic long-term competitive advantage and a critical co-producer of its long-term success. Implications and the need for further research are discussed

Improving Small Business Viability Through the Strategic Longevity and Health Maintenance Evaluation

Most adults are urged to go through an annual health checkup. We recommend that most mature small businesses perform an annual strategic longevity and health maintenance evaluation as well to ensure their viability. To this end, we provide strategic areas of critical importance to a small business viability and longevity and offer guidelines for small business owners, managers, consultants, and small business/entrepreneurship educators use to help improve performance. We add to the body of literature on small business success and failure factors by emphasizing the need for a closer look at the open systems nature of these businesses and the impact of interaction with the larger external environmental system for viability. We urge small business owners to be more proactive in evaluating the health and viability of their businesses by using systems approach before the emergence of signs of trouble through the use of the Annual Health Maintenance and Viability Evaluation checklist. We recommend the use of the checkup for use by consultants including SBI student consulting projects

A physics-based model for frost buildup under turbulent flow using direct numerical simulations

We present a new model for frost buildup under turbulent (and laminar) flow using direct numerical simulations. The physical model consists of two layers, the air and the frost. The air layer is fully resolved and consists of solving for the velocity, temperature, and vapor mass fraction fields. The frost layer thickness is resolved using conservation of mass and energy. Both phases are dynamically coupled using the immersed boundary method. Three-dimensional simulations are conducted in an open-channel configuration. A number of challenges need to be overcome to make these simulations feasible. First, to enforce far-field conditions of zero gradient and prescribed mean temperature and humidity, a source term is added to the energy and transport equations in the flow solver. Second, the mean frost thickness is subtracted after each time step to ensure a constant mean flow thickness and level of turbulence in the numerical domain. Third, a slow-time acceleration approach, which accelerates the frost buildup by a predetermined factor, is employed to bridge the gap between the fast turbulent and slow frost buildup time scales. Finally, a frost densification scheme is used to overcome the difficulties of vertically varying frost properties. The model is validated by comparing the frost thickness and frost thickness buildup rate over a period of one hour from a cooled flat plate experiment. Both quantities compare favorably with experiments

Numerical study of natural convection boiling in a partially heated Rayleigh-Bénard cell

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This paper presents a numerical investigation on Rayleigh-Bénard (RB) cell with natural convective liquid boiling, which is vastly different to thermo-fluids nature of its classic single phase counter-part. The study develops a simulation model and examines the unique fluid and thermal characteristics associated with this two-phase RB cell for a range of heater power. The boiling heat transfer curve is obtained covering single phase to boiling process within the RB cell while identifying its unique fluid features. Unlike cellular convective structures in single-phase RB cell, the analysis on this boiling RB cell indicates a fast rising fluid plume emulating “siphoning” fluid action that develops according to heating levels and vapour composition. It also shows that the vapour bubble dynamics critically influence and determine vapour migration within the boiling fluid and heater surface thermal patterns, making this cell behaviour uniquely different to that of traditional RB cell and conventional pool boiling.cf201

Hydrometeorological threshold conditions for debris flow initiation in Norway

Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID) thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN). For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day<sup>−1</sup>. Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day<sup>−1</sup>. The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold

The effect of caffeine ingestion in prevention of post-operative ileus after caesarean section: a randomized controlled trial

Background: Caesarian section (CS) has become more prevalent than the vaginal delivery in Egypt. Many complications could occur after an abdominal surgery. One of the commonest but yet serious complications is the postoperative ileus that can possibly be prevented by caffeine ingestion. The aim of the study is to assess the value of caffeine ingestion in promoting intestinal motility and prevention of postoperative ileus after CS.Methods: This is a randomized controlled trial that was conducted on 560 cases who were recruited from emergency unit and inpatient wards in Ain Shams University maternity hospital. The patients were divided into two groups where the intervention group received caffeinated coffee while the other group received decaffeinated coffee.Results: There was statistically significant difference between the two groups regarding the bowel function after CS (p <0.05). The intervention group had improved intestinal functions after the CS. Patients from the intervention group had audible intestinal sound sooner than the control group. In addition, they passed flatus and were able to tolerate food in less time.Conclusions: Consuming caffeinated coffee after CS contributes significantly to faster restoration of intestinal function. Coffee is a popular drink and can be used to decrease the incidence of postoperative ileus-related complications