Uncertain Price Competition in a Duopoly with Heterogeneous Availability

We study the price competition in a duopoly with an arbitrary number of buyers. Each seller can offer multiple units of a commodity depending on the availability of the commodity which is random and may be different for different sellers. Sellers seek to select a price that will be attractive to the buyers and also fetch adequate profits. The selection will in general depend on the number of units available with the seller and also that of its competitor - the seller may only know the statistics of the latter. The setting captures a secondary spectrum access network, a non-neutral Internet, or a microgrid network in which unused spectrum bands, resources of ISPs, and excess power units constitute the respective commodities of sale. We analyze this price competition as a game, and identify a set of necessary and sufficient properties for the Nash Equilibrium (NE). The properties reveal that sellers randomize their price using probability distributions whose support sets are mutually disjoint and in decreasing order of the number of availability. We prove the uniqueness of a symmetric NE in a symmetric market, and explicitly compute the price distribution in the symmetric NE.Comment: 45 pages, Accepted for publication in IEEE Transaction on Automatic Contro

Economics Of Non-Neutrality In The Internet

Net-neutrality on the Internet is the set of policies that prevents a paid or unpaid discrimination by Internet Service Providers (ISPs) among different types of transmitted data. The recent moves to change the net neutrality rules and the growing demand for data have driven the ISPs to provide differential treatment of traffic to generate additional revenue streams from Content Providers (CPs). In this thesis, we consider economic frameworks to investigate different questions about the departure toward a non-neutral regime and its possible consequences. In particular, we i) assess whether different entities of the market have the incentive to adopt a non-neutral pricing scheme; and if yes ii) what are the pricing strategies they choose; and iii) how these changes affect the Internet market. First, we investigate the incentives of different entities of the Internet market for migrating to a non-neutral regime. Thus, we consider early stages of a non-neutral Internet. We consider a diverse set of parameters for the market, e.g. market powers of ISPs, sensitivity of EUs and CPs to the quality of the content. The goal is to obtain founded insights on whether there exists a market equilibrium, the structure of the equilibria, and how they depend on different parameters of the market when the current equilibrium (neutral regime) is disrupted and some ISPs have switched to a non-neutral regime. Then, we seek to investigate frameworks using which ISPs and CPs select appropriate incentives for each other, and investigate the implications of these new schemes on the entities of the Internet market. We analyze two non-neutral frameworks. In the first framework, we focus on the price competition between ISPs in the presence of uncertainty in competition and demand when CPs, i.e. demand, is merely price taker, i.e. passive in equilibrium selection. Then, in the second framework, we consider the case in which CPs have an active role in the market, and decide on the number of resources they want to reserve/buy from ISPs based on the price ISPs quote. In this case, we also consider the coupling between limited resources and the quality of the content delivered to end-users and subsequently the strategies of the decision makers. We obtain strategies for ISPs and CPs under a variety of market dynamics

Effects of storage duration and conditions on mechanical properties of Viola cucumber fruit under compression loading

In this research, the effects of storage duration and storage conditions on mechanical properties of cucumber fruit (Viola variety) were evaluated at different positions of the fruit length.  The cucumber fruit mechanical properties determined in this study were firmness, apparent modulus of elasticity, failure stress, failure strain and failure energy.  The mechanical properties determined under compression loading using puncture and uni-axial compression tests.  The results showed that the storage duration, storage conditions and fruit test position had significant (P<0.01) effect on the mechanical properties of Viola cucumber fruit.  The samples firmness, modulus of elasticity, failure stress and failure energy reduced about 49%, 39%, 38% and 33%, respectively during shelf life.  The failure strain of samples increased 18% during storage time.  Changing the mechanical properties of the cucumber fruit at room conditions was faster than refrigerator conditions.  The mechanical properties were differed along the length of cucumber fruits so that near the stem region of cucumber fruit had the maximum value of firmness, modulus of elasticity, failure stress and failure energy.  The sample failure strain had the minimum value at near the stem region of cucumber fruit.  Among the mechanical parameters that were evaluated in this research work, the firmness can be considered as the most appropriate parameter to evaluate textural properties of Viola cucumber fruit due to significant effect of independent parameters on it and ease of usage

The trend of marriage, childbearing, and divorce and its determinants of socioeconomic factors on divorce in Yazd province 2016-2021: A cross-sectional study

Background: In recent decades, families and their stability as an important social institution have changed significantly. Objective: This study aimed to investigate the marriage trends, childbearing, and divorce changes in Yazd province from 2016 to 2021 to estimate the effect of socioeconomic factors on divorce. Materials and Methods: A cross-sectional study was done in 2 phases. In the first phase, an ecological (time trend) was conducted to investigate the 5 yr trend in the occurrence of marriage, childbearing, and divorce, as well as the factors affecting the occurrence of divorce in the second phase. For the second phase of the study, 600 participants were selected. 300 divorced and 300 married applicants were chosen between 2016 and 2021. A binary logistic regression model was used to find the related factors affecting the occurrence of divorce. Results: The results showed a declining marriage (p = 0.05) and childbearing trend (p = 0.84), as well as an increasing trend in divorces (p = 0.02) in Yazd. Logistic regression analysis showed that college education (OR = 0.22, CI: 0.116-0.430, p < 0.001) and being self-employed (OR = 0.48, CI: 0.255-0.934, p = 0.03) could reduce the odds of divorce. In addition, nonresidents (OR = 2.1, CI: 1.314-3.562, p < 0.001), with > 10-yr age differences (OR = 3.8, CI: 1.803-8.213, p < 0.001) or the woman being older than her husband (OR = 3.4, CI: 1.981-5.848, p < 0.001) could increase the odds of divorce. Conclusion: Our results confirmed that a combination of socioeconomic characteristics affects the stability of family institutions. Key words: Family, Marriage, Childbearing, Divorce, Socioeconomic factors

The Impact of the COVID-19 Pandemic on Hospitalization Rates due to Prosthetic Valve Thrombosis

Backgrounds: Studies have shown a decline in the admission rates of various diseases during the COVID-19 pandemic. Prosthetic valve thrombosis (PVT) is a rare condition followed by surgical or transcatheter valvular interventions. Considering the lack of data on hospitalization rates due to PVT during the pandemic, this study evaluated the implications of the COVID-19 pandemic on PVT admissions and characteristics in a tertiary referral center. Methods: Data from all the consecutive patients hospitalized due to PVT between February 2020 and February 2021 (the first year of the pandemic) were collected from medical records and compared clinically with the corresponding time before the pandemic (February 2019 through February 2020). Variables of interest included the number of hospitalization, patient and valve characteristics, diagnostic and management strategies, and in-hospital events. Results: Forty patients (32.5% male, age: 54.0 [46.5-62.0 y] comprised the study population. We observed a considerable decline in hospitalization rates during the pandemic, from 31 to 9 patients. Admitted patients were 8 years younger, had a higher proportion of the New York Heart Association functional class III or IV symptoms (44.4% vs 22.6%), were more often treated with fibrinolysis (33.3% vs 22.6%) or surgical approaches (33.3% vs 22.6%), and were discharged 6 days sooner. Conclusion: We described a reduction in PVT hospitalization. Patients presented with a higher proportion of severe dyspnea and had increased treatment with fibrinolysis/surgical approaches. These observations highlight the necessity of the active surveillance of patients with prosthetic valves by caregivers for timely diagnosis and appropriate management during the pandemic