544 research outputs found
Pricing differentiated brokered internet services
Price war, as an important factor in undercutting competitors and attracting customers, has spurred considerable work that analyzes such conflict situation. However, in most of these studies, quality of service (QoS), as an important decision-making criterion, has been neglected. Furthermore, with the rise of service-oriented architectures, where players may offer different levels of QoS for different prices, more studies are needed to examine the interaction among players within the service hierarchy. In this paper, we present a new approach to modeling price competition in service-oriented architectures, where there are multiple service levels. In our model, brokers, as the intermediaries between end-users and service providers, offer different QoS by adapting the service that they obtain from lower-level providers so as to match the demands of their clients to the services of providers. To maximize profit, players at each level, compete in a Bertrand game, while they offer different QoS. To maintain an oligopoly market, we then describe underlying dynamics which lead to a Bertrand game with price constraints at the providers' level. Numerical examples demonstrate the behavior of brokers and providers and the effect of price competition on their market shares.http://www.cs.bu.edu/fac/matta/Papers/sdp2016.pdfAccepted manuscrip
The effect of competition among brokers on the quality and price of differentiated internet services
Price war, as an important factor in undercutting competitors and attracting customers, has spurred considerable work that analyzes such conflict situation. However, in most of these studies, quality of service (QoS), as an important decision-making criterion, has been neglected. Furthermore, with the rise of service-oriented architectures, where players may offer different levels of QoS for different prices, more studies are needed to examine the interaction among players within the service hierarchy. In this paper, we present a new approach to modeling price competition in (virtualized) service-oriented architectures, where there are multiple service levels. In our model, brokers, as the intermediaries between end-users and service providers, offer different QoS by adapting the service that they obtain from lower-level providers so as to match the demands of their clients to the services of providers. To maximize profit, players, i.e. providers and brokers, at each level compete in a Bertrand game while they offer different QoS. To maintain an oligopoly market, we then describe underlying dynamics which lead to a Bertrand game with price constraints at the providers' level. Numerical simulations demonstrate the behavior of brokers and providers and the effect of price competition on their market shares.This work has been partly supported by National Science Foundation awards: CNS-0963974, CNS-1346688, CNS-1536090 and CNS-1647084
The effect of (non-)competing brokers on the quality and price of differentiated internet services
Price war, as an important factor in undercutting competitors and attracting customers, has spurred considerable work that analyzes such conflict situation. However, in most of these studies, quality of service (QoS), as an important decision-making criterion, has been neglected. Furthermore, with the rise of service-oriented architectures, where players may offer different levels of QoS for different prices, more studies are needed to examine the interaction among players within the service hierarchy. In this paper, we present a new approach to modeling price competition in (virtualized) service-oriented architectures, where there are multiple service levels. In our model, brokers, as intermediaries between end-users and service providers, offer different QoS by adapting the service that they obtain from lower-level providers so as to match the demands of their clients to the services of providers. To maximize profit, players, i.e. providers and brokers, at each level compete in a Bertrand game while they offer different QoS. To maintain an oligopoly market, we then describe underlying dynamics which lead to a Bertrand game with price constraints at the providers’ level. We also study cooperation among a subset of brokers. Numerical simulations demonstrate the behavior of brokers and providers and the effect of price competition on their market shares.Accepted manuscrip
The Rise of Crime in Affordable Housing in Suburbs, Case of Iran
Housing is one of the fundamental needs for human to respond their primary needs such as food, rest, cleaning and having family, in other words, everything that related to the needs of body and soul of a human. Nowadays by increasing the population in the world the suitable shelter becomes a real problem. In the point of economic also the prices of the houses increase too much so it is not affordable for low-income people to have shelter easily. After the revolution in Iran country, there is huge immigration from the rural part to metropolitan areas. Most of these peoples belong to a low-income family, new couples and labours. Governments try to solve this problem by creating some policies. The aim of this study is to analyze the crime in affordable houses located in suburbs area. This research will answer the important factor that causes crime in affordable housing in suburbans. The case study in this research is Mehr houses created for low-income people in Iran. This research analyzed the factors which may cause to raise the crime in that area based on the literature review and previous analysis by different theories in this field. Data is collected by literature review, news, books, papers. The result of this research confirms the possibility of Mehr affordable houses in suburbs transfer to the area that raises the crime
Multi-attribute demand characterization and layered service pricing
As cloud computing gains popularity, understanding the pattern and structure of its workload is increasingly important in order to drive effective resource allocation and pricing decisions. In the cloud model, virtual machines (VMs), each consisting of a bundle of computing resources, are presented to users for purchase. Thus, the cloud context requires multi-attribute models of demand. While most of the available studies have focused on one specific attribute of a virtual request such as CPU or memory, to the best of our knowledge there is no work on the joint distribution of resource usage. In the first part of this dissertation, we develop a joint distribution model that captures the relationship among multiple resources by fitting the marginal distribution of each resource type as well as the non-linear structure of their correlation via a copula distribution. We validate our models using a public data set of Google data center usage.
Constructing the demand model is essential for provisioning revenue-optimal configuration for VMs or quality of service (QoS) offered by a provider. In the second part of the dissertation, we turn to the service pricing problem in a multi-provider setting: given service configurations (qualities) offered by different providers, choose a proper price for each offered service to undercut competitors and attract customers. With the rise of layered service-oriented architectures there is a need for more advanced solutions that manage the interactions among service providers at multiple levels. Brokers, as the intermediaries between customers and lower-level providers, play a key role in improving the efficiency of service-oriented structures by matching the demands of customers to the services of providers. We analyze a layered market in which service brokers and service providers compete in a Bertrand game at different levels in an oligopoly market while they offer different QoS. We examine the interaction among players and the effect of price competition on their market shares. We also study the market with partial cooperation, where a subset of players optimizes their total revenue instead of maximizing their own profit independently. We analyze the impact of this cooperation on the market and customers' social welfare
A Discussion on Affordable Housing Projects; Case Study Mehr Housing, Iran
Housing is one of the basic needs of humans. Families in different countries with various cultures, who have different lifestyles respond to their individual needs including physical and mental in a safe place that is called house. The world population is increasing day by day. In parallel to this population growth, housing demand increases rapidly. Iran is also a country, which has a rapid population growth and has developed a series of policies to solve the housing problems. Affordable housing is one of solution for providing the house by governments. These type of houses is the ways to answer the demand for low-income people or the people that their income is not sufficient to the owner a house. Since 2007, the government has built a new type of affordable housing in different cities of Iran. These houses are named as Mehr Housing, which is generally medium and high-rise buildings for low-income people. In this study, it is intended to make an evaluation of the strengthens and weaknesses of Mehr Housing projects in Iran in terms of housing quality. These analyses are mainly done based on location and accessibility, safety and security, public open spaces and recreational activities, plan layout of housing units and physical features. By this discussion, it is expected to create a guide for the policymakers, designers, users and other shareholders
The effect of peer group training on self-care of elderly with diabetes mellitus
Background and aims: The prevalence of chronic diseases, such as diabetes mellitus, in elderly can be controlled with training self-control behaviors, especially in peer groups. Regarding to specific conditions and greater rate of complications in the elderly, the peer group self-care education is in specific importance among these patients. The present study was aimed to investigate the effect of peer group training on the self-care of elderly with diabetes in selected health centers of Isfahan.
Methods: The present clinical trial compared 21 elderly patients with diabetes higher than 65 years old trained by a peer educator and 23 elderly patients received training by none peer group (trained by a researcher) for 4 months. The samples were randomly divided into two groups. The self-care behaviors were assessed by a questionnaire in 4 dimensions of diet, sport, glucose test, and diabetic drugs and the results were compared between groups. T-independent for statistical tests and to compare three times in a group was used ANOVA with repeated observations.
Results: The total score of self-care in the test group increased significantly from 31±5.61 before intervention, to 42±7.01 after intervention and 35.55±5.11 one month after intervention, while the control group had no significant change. Different dimensions of the questionnaire were not statistically with a significant difference between groups, except in the field of sports was significant a month later intervention (P=0.05). There was a direct relationship between level of education and self-care score.
Conclusion: According to the findings, training the elderly patients with diabetes by a peer group can promote their self-care. Therefore, training with a peer group is advised as an efficient method for improving self-care of elderly diabetic patients
The effect of peer group training on self-care of elderly with diabetes mellitus
Background and aims: The prevalence of chronic diseases, such as diabetes mellitus, in elderly can be controlled with training self-control behaviors, especially in peer groups. Regarding to specific conditions and greater rate of complications in the elderly, the peer group self-care education is in specific importance among these patients. The present study was aimed to investigate the effect of peer group training on the self-care of elderly with diabetes in selected health centers of Isfahan.
Methods: The present clinical trial compared 21 elderly patients with diabetes higher than 65 years old trained by a peer educator and 23 elderly patients received training by none peer group (trained by a researcher) for 4 months. The samples were randomly divided into two groups. The self-care behaviors were assessed by a questionnaire in 4 dimensions of diet, sport, glucose test, and diabetic drugs and the results were compared between groups. T-independent for statistical tests and to compare three times in a group was used ANOVA with repeated observations.
Results: The total score of self-care in the test group increased significantly from 31±5.61 before intervention, to 42±7.01 after intervention and 35.55±5.11 one month after intervention, while the control group had no significant change. Different dimensions of the questionnaire were not statistically with a significant difference between groups, except in the field of sports was significant a month later intervention (P=0.05). There was a direct relationship between level of education and self-care score.
Conclusion: According to the findings, training the elderly patients with diabetes by a peer group can promote their self-care. Therefore, training with a peer group is advised as an efficient method for improving self-care of elderly diabetic patients
Predicted ten-year risk of cardiovascular disease among patients without prior heart disease or stroke using atherosclerotic cardiovascular disease risk calculator
Objective: Recognition of probable risk factors for cardiovascular disease is crucial in non-CAD patients for preventive programming. The purpose was determination of 10-year cardiovascular disease (CVD) among patients without current cardiovascular disease.
Material & Methods: In this observational study that was performed as a diagnostic survey, 606 consecutive patients without current cardiovascular disease, referring to Modarres and Loghman Hospitals, Tehran, Iran in 2017 and 2018 were enrolled and ASCVD plus score determined the 10-year cardiovascular disease among them.
Results: The results in this study demonstrated that mean ASCVD plus score was 13.1 ± 14.9 points. Among cases 284 (40.9%), 67 (11.1%), 154 (25.4%), and 137 (22.6%) patients were in groups 1, 2, 3, and 4, respectively. The mean risk was higher in men, diabetics, smoker, users of anti-hypertensive, statins, and aspirin, older, with higher blood pressure, and also with higher total and LDL cholesterols.
Conclusion: Totally, according to the obtained results in current study, it may be concluded that 10-year risk of cardiovascular disease is relatively high among patients without current cardiovascular disease. This matter shows the importance of routine screening in such population.
 
The Propagation of Laser Light in Skin by Monte Carlo- Diffusion Method: A Fast and Accurate Method to Simulate Photon Migration in Biological Tissues
INTRODUCTION: Due to the importance of laser light penetration and propagation in biological tissues, many researchers have proposed several numerical methods such as Monte Carlo, finite element and green function methods. Among them, the Monte Carlo method is an accurate method which can be applied for different tissues. However, because of its statistical nature, Monte Carlo simulation requires a large number of photon pockets to be traced, so it is computationally expensive and time- consuming. Although other numerical methods based on the diffusion method are fast, they have two important limitations: first, they are not valid near the bounder of sample and source, and second, their accuracy is less than Monte Carlo method.METHODS: In this study, we combine the accuracy of Monte Carlo method and speed of the diffusion method. This hybrid method is faster than Monte Carlo Method and its accuracy is higher than the diffusion method.RESULTS: We first evaluate this hybrid model and the reflectance of a biological phantom is calculated by Monte Carlo method and this hybrid model. Then the propagation of laser light in the skin tissue has been studied.CONCLUSION: In this study, a combined method based on the Monte Carlo method and the diffuse equation is introduced. This hybrid method is five times faster than Monte Carlo Method, and its accuracy is higher than the diffusion method. The propagation of laser light in skin has also been studied by this hybrid method and its accuracy shows that it can be applied for laser penetration in biological tissues. It seems that this method is good for photo dynamic therapy (PDT) and optical imagin
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