Today entrepreneurship is considered as the economic driving engine for developed and developing countries and most countries have invested considerably on entrepreneurship development. The entrepreneurship development in a community could provide sustainable employment and economic development. It should be noted that entrepreneurship development has always been encountered different challenges and barriers. The present article is aimed to detect and classify the barriers of entrepreneurship development in Iranian SMEs and determine the importance of each barrier. Analyzing 28 detected barriers in the present study show that lack of sufficient knowledge in management skills, business management, lack of adequate investment to start and retain a business, difficulty in finding information about markets, products and prices, troublesome rules obtaining bank loans, and the difficulty in recruiting good and reliable staff are the most important barriers and challenges of corporate entrepreneurship development in Iranian SMEs.

In recent decades, one of the scientists’ main concerns has been to improve the accuracy of satellite attitude, regardless of the expense. The obvious result is that a large number of control strategies have been used to address this problem. In this study, an adaptive neuro-fuzzy integrated system (ANFIS) for satellite attitude estimation and control was developed. The controller was trained with the data provided by an optimal controller. Furthermore, a pulse modulator was used to generate the right ON/OFF commands of the thruster actuator. To evaluate the performance of the proposed controller in closed-loop simulation, an ANFIS observer was also used to estimate the attitude and angular velocities of the satellite using magnetometer, sun sensor, and data gyro data. However, a new ANFIS system was proposed that can jointly control and estimate the system attitude. The performance of the proposed controller was compared to the optimal PID controller in a Monte Carlo simulation with different initial conditions, disturbance, and noise. The results show that the proposed controller can surpass the optimal PID controller in several aspects including time and smoothness. In addition, the ANFIS estimator was examined and the results demonstrate the high ability of this designated observer. Consequently, evaluating the performance of PID and the proposed controller revealed that the proposed controller consumed less control effort for satellite attitude estimation under noise and uncertainty.

Scheduling and planning for allocating resources to the activities so that the activities can be done in the best manner and resources allocated appropriately is one of the most important problems of management and operation research. The hospitals are one of the organizations that face with this problem in allocating nurses to the shifts in the most appropriate time period so precisely that the defections could not be eliminated and the goals are achieved. Therefore, the present study was aimed to develop a model for nurse scheduling through goal programing technique. The proposed model includes different purposes as its goals and strives to achieve them. This model can be used for solving similar problems in the urgency units in hospitals. This problem has been solved by Lingo 8 and finally its results have been compared with the results of manual methods.

The objective of this paper is to calculate the completion time of various network paths according to which project completion time could be calculated. Critical Path Method (CPM) is used to determine project completion time if the time to conduct activities is definite. But if time of conducting activities is probable, Program Evaluation and Review Technique (PERT) method must be used and if occurring activities is possible, Graphical Evaluation and Review Technique (GERT) method should be applied. The current project control software usually cannot perform calculations for the last two states. Moreover, using manual methods is impossible if the network is composed of several activities. Thus applying the simulation approach is an appropriate method in such states. Simulation is used as a strong tool to analyze systems because it has a close relationship with real systems and considers many complicated relations in them. It is intended to determine project completion time and critical path in this survey given that time of activities is probable and each activity is the prerequisite to another. ARENA software has been used to do so which is based on simulation method.

The single-machine scheduling problem is the basis of scheduling theories. Because some of the production activities are completed earlier or later than standard time, they create several earliness and tardiness penalties. On the other hand, it is necessary to consider just in time philosophy and its importance in the scheduling problems. Therefore, this study seeks to develop a goal function for optimizing single-machine scheduling problems that combines both earliness and tardiness penalties. This study also is determined to minimize the earliness and tardiness penalties in this area. The restricted due date also has multiple effects on the optimum time. This is why that the present study also was aimed to examine the singlemachine scheduling problems with focus on the earliness and tardiness penalties that considering restricted due date simultaneously. The proposed model of this study is an efficient method for understanding the importance of just in time in the scheduling problems.