3,920 research outputs found
A synthesis of location models
This article considers a model of spatial competition where firms and consumers are located in a semicircular space rather than in the whole circle (Salop's model) or the linear city (Hotelling's model), under the assumptions of both, convex and concave, transportation costs. The paper tries to generalize the results of the two previous models. We find that for concave transportation costs the existence of a price equilibrium is warranted for every firms' location when the length of the semicircular space is greater than 3/4. For the convex case, perfect equilibrium is only obtained when the size of the market segment is equivalent to Hotelling's linear model.
Optimized Household Demand Management with Local Solar PV Generation
Demand Side Management (DSM) strategies are of-ten associated with the
objectives of smoothing the load curve and reducing peak load. Although the
future of demand side manage-ment is technically dependent on remote and
automatic control of residential loads, the end-users play a significant role
by shifting the use of appliances to the off-peak hours when they are exposed
to Day-ahead market price. This paper proposes an optimum so-lution to the
problem of scheduling of household demand side management in the presence of PV
generation under a set of tech-nical constraints such as dynamic electricity
pricing and voltage deviation. The proposed solution is implemented based on
the Clonal Selection Algorithm (CSA). This solution is evaluated through a set
of scenarios and simulation results show that the proposed approach results in
the reduction of electricity bills and the import of energy from the grid
Antenna with artificial magnetic conductor for wireless application
— This paper discussed the recent works on Artificial
Magnetic Conductor (AMC) with the antenna. Two different
application for antenna with AMC have been discussed. The
first application is the antenna with AMC that has been used for
RFID system to detect the metal object. Without incorporating
AMC with antenna the system cannot be detected. When the
AMC is attached with the RFID Tag antenna the system is back
to normal where longer distance is achieved. The second
application is used for flexible AMC using textile material for
signal transmission enhancement. Using two antennas for on
body application the system has been tested using AMC and
without AMC. It shows that the transmission is better when
there is an AMC attach to the body compared without AMC.
Index Terms — Artificial Magnetic Conductor, high
impedance surface, metamaterial, reflection phase
Drivers' perceptions of unsafe driving behaviors and their countermeasures: a study in Saudi Arabia
There is an increased public concern about the role of aggressive driving and "road rage" in crashes and traffic fatalities. There is no general agreement as to what constitutes aggressive driving. Consequently, the objective of the study was to survey of the perceptions on the specific unsafe driving acts. Perceptions and beliefs of drivers about unsafe and aggressive driving actions and their countermeasures are presented in this paper. The study primarily looked at the wide range of driver attitudes about speeding and other forms of unsafe driving behavior. The study was conducted in Jeddah, the second largest city of Saudi Arabia by interviewing a sample of 300 drivers. The results indicated that the drivers, in general, prefer to drive at higher speeds and could be considered as more aggressive compared to the drivers in the United States. The most dangerous reported driving act was "drive thru red light", followed by "racing another driver". Only 23% of the drivers thought that it was dangerous to drive over 30 km of the legal speed limits. The most often seen unsafe driving action was "speeding (70%), followed by "driving too closely (57%), "failing to use turn signals (53%), "drive inattentively (50%)", and "running red lights (43%)". The main causes of unsafe driving behaviors were "being in a hurry/time pressure (66%)", "aggressive behavior of others (52%)", and "refusing traffic rules (51%)". The countermeasure that was viewed to be the most effective in reducing unsafe driving behaviors was assigning more traffic police officers (66%). The study revealed that, more than half the drivers believed that more frequent ticketing (60%), doubling or tripling fines (54%), and doubling the length of imprisonment (53%) would be effective in reducing unsafe driving behavior
Magnetohydrodynamics in Biomedical Applications
This chapter discusses recent advances in biomedical applications of magnetohydrodynamics (MHD). The magnetohydrodynamic (MDH) effect is a physical phenomenon describing the motion of a conducting fluid flowing under influencing of an external magnetic field. The chapter covers four primary areas of research: (1) laser beam scanning, (2) nano-particle manipulation, (3) imaging contrast enhancement, and (4) targeted drug delivery. The state-of-the-art devices based on magnetohydrodynamic principles are also presented, providing a broad view of biomedical MHDs. As the field of biomedical MHDs continues to grow, advances towards micro-scale transitions will continue to be made, maintaining its clinically driven nature and motion towards real-world applications
Pattern and severity of childhood unintentional injuries in Ismailia city, Egypt
In 2009, more than 746 000 injury cases were registered in the Ministry of Health hospitals in Egypt, with an injury rate of 1 004/100 000 population. Around 38% of all injuries occur among children and young adults less than 20 years of age. Furthermore, more than 20 000 people lose their lives to injuries every year (27/100 000). However, these data lack information on injury pattern, severity, provided care and outcome of injuries, which are essential data for planning injury control programmes.The aim of this study was to determine the frequency, nature and risk factors of childhood injuries in the Suez Canal University Hospital Emergency Department.The study included a total of 551 children of 12 years of age. The most common causes of injuries among those children were falls (60%), road traffic injuries (15%) and burns (7%). The most commonly sustained injuries were fractures (23%), cuts or open wounds (21%), sprains (20%) and burns (13%). Overall injury severity scores (ISSs) were low across all injury types, except road traffic injuries (RTIs). The majority of patients were treated and discharged without disability (50.5%), while 7.4% had long-term temporary disability that lasted for more than 6 weeks, and 1.9% sustained permanent disability. There were two deaths (0.4% proportionate mortality); both of them were due to falls from a height.In conclusion, the study confirms the feasibility of documenting the burden of childhood injuries on health systems in Egypt. It also confirmed the need for tailored injury-prevention research in Egypt. The resulting data should encourage interventional trials to be conducted, appropriate injury-prevention strategies to be implemented and timely interventions to be planned.Keywords: Childhood unintentional injuries, Egypt, risk factors
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