On the Complexity of Chore Division

We study the proportional chore division problem where a protocol wants to divide an undesirable object, called chore, among $n$ different players. The goal is to find an allocation such that the cost of the chore assigned to each player be at most $1/n$ of the total cost. This problem is the dual variant of the cake cutting problem in which we want to allocate a desirable object. Edmonds and Pruhs showed that any protocol for the proportional cake cutting must use at least $\Omega(n \log n)$ queries in the worst case, however, finding a lower bound for the proportional chore division remained an interesting open problem. We show that chore division and cake cutting problems are closely related to each other and provide an $\Omega(n \log n)$ lower bound for chore division

The Analysis of the Internal and External Environments of Private Institutions of Higher Education in Iran and Providing Optimal Strategies Based on SWOT

The government policies of Islamic Republic of Iran in the framework of Development Plan Law, on the one hand, and the activaion of private sector in the country's educational structure, the sphere of higher education in Iran is faced with dramatic changes in the last decade. Meanwhile, the rapid development of non-governmental private institutions of higher education due to the increasing social demand for entry to higher education in Iran is important. But soon the problems and challenges faced by institutions such as the reduced quality of education, seats left empty and financial losses incurred eventually lead to bankruptcy and closing of a number of them. In this research, due to the special role of private higher education institutions in providing educational services, the need of the country to establish specialized institutions and also the wave of migration of students to the universities with poor quality abroad, the current situation of the country and the challenges faced by private higher education institutions in Iran are descrobed. Through interviews with 10 expert teachers, the strengths, weaknesses, opportunities and threats of these institutions based on SWOT are determined and the optimal strategies for the excellence of them are introduced that Defensive position non-profit institutions of higher education in Iran have been achieved. Keywords: Private Higher Education Institutions, Analysis of SWOT, Optimal Strategie

RECOGNITION AND PRIORITY OF KEY SUCCESS FACTORS (KSF) INCUSTOMERS CLUBS AND CUSTOMERS LOYALTY PROGRAMS

The present study aims to identify and prioritize the Key Success Factors (KSFs) of Customer clubs and Customer Loyalty programs, in Bank Mellat Iran. The different models of Key Success Factors from previous researchers have been studied, and according to 12 experts of bank Mellat Iran, a model of KSFs of Customer clubs and Customer Loyalty programs in banking industry, has been presented. It’s a combination of previous researches models, including 20 factors affecting the success of Bank Customer clubs and Customer Loyalty program. A questionnaire of 20 success factors have been designed for determining the effect of each factor on the other 19 factors. It has been filled by 12 experts with over 10 years of experience in banking industry. Then, it has been analyzed by Fuzzy DEMATEL method, and the research results has been extracted. This research concluded 20 main key success factors of Customer clubs and Customer Loyalty programs, in Bank Mellat Iran; the 5 fist most important success factors are in order as: 1. the seller's contact assets, 2. price, discounts and free products, 3. Lack of attention to monitoring system and continuous supervision, 4. Quality of customer services, 5. Creating value for customers

Analysis of Network Coding in a Slotted ALOHA-based Two-Way Relay Network

This paper deals with a two-way relay network (TWRN) based on a slotted ALOHA protocol which utilizes network coding to exchange the packets. We proposed an analytical approach to study the behavior of such networks and the effects of network coding on the throughput, power, and queueing delay of the relay node. In addition, when end nodes are not saturated, our approach enables us to achieve the stability region of the network in different situations. Finally, we carry out some simulation to confirm the validity of the proposed analytical approach

The reliability and validity of the persian version of sinonasal outcome test 22 (Snot22) questionnaires

Background: The quality of life (QOL) is an important indicator for disease-severity classification and outcome measurement in obtaining treatment sinonasal diseases. The sinonasal outcome test 22 (SNOT 22) questionnaire has been introduced as the best specific sinonasal instrument for QOL measurement. Objectives: To prepare a valid and reliable Persian language version of SNOT 22 questionnaire. Patients and Methods: After forward and backward translation of the original version of SNOT 22 questionnaire from English to Persian, a group of patients with nasal septal deviation who need septal surgery and another group of healthy volunteers answered the Persian version of the questionnaire. The responsiveness rate, validity (Pearson correlations and differential validity) and reliability (internal consistency and test-retest reliability) of the 22 items of the questionnaire was calculated. P value < 0.05 was considered significant. Results: Thirty adults with nasal septal deviation need surgical correction and 30 healthy volunteers were included (mean age 30.4 ± 7.1 vs. 33 ± 6.7, P value = 0.148). The questionnaire was introduced to subjects two times with a two-week-period gap. Total responsiveness rate for 22 items was more than 97%. The total Cronbach's Alfa coefficient was 0.898 (ranging 0.890-0.903). The Pearson correlations were 0.85 and 0.96 for patients and healthy volunteers, respectively. The mean total score were 25.6 ± 13.3 (range 6-52) and 7.6 ± 9.1 (range 0-45) in patients and healthy volunteers, respectively (P < 0.0001). The subscales scores were also significantly different between two groups. Conclusions: The Persian version of SNOT 22 questionnaire is a valid and reliable instrument for accessing sinonasal diseases in Persianspeaking people