Time, cost and quality are considered as the main components in managing each project. Previous researches have mainly focused on the time-cost trade-off problems. Recently quality is considered as the most important factor in project�s success, which is influenced by time acceleration that is the less time is spent the more success is gained. In time-cost-quality trade-off problems, each activity can be done in various execution modes and determination of these execution modes is seen as to minimize the project time and cost and maximize its quality .In this paper, three integer programming models are provided and one of the main objectives is optimized in each model by assigning the proper bound to other objectives. Following the non-dominated solutions obtained by solving models, and by means of hybrid approach of Fuzzy AHP strategy and VIKOR method regarded as multi-criteria decision making methods, the best possible alternative (from among non-dominated solutions) has been suggested.Fuzzy AHP method has been used to determine the importance rate of each objective. In this method linguistic variables were used which take us closer to reality. At the end, with applying these weights in VIKOR method, the best possible alternatives (among non-dominated solutions) were found. Using this hybrid approach can help managers, to a great extent, in selecting the appropriate solution so that maximum desirability is obtained due to the importance rate of the objective functions from the viewpoint of decision maker. Manuscript profile

In this paper, the problem of population districting in the health system of South Khorasan province has been investigated in the form of an optimization problem. Now that the districting problem is considered as a strategic matter, it is vital to obtain efficient solutions in order to implement in the system. Therefore in this study two meta-heuristic algorithms, Ant Lion Optimizer (ALO) and Grey Wolf Optimizer (GWO), have been applied to solve the problem in the dimensions of the real world. The objective function of the problem is to maximize the population balance in each district. Problem constraints include unique assignment as well as non-existent allocation of abnormalities. Abnormal allocation means compactness, lack of contiguous, and absence of holes in the districts. According to the obtained results, GWO has a higher level of performance than the ALO. The results of this problem can be applied as a useful scientific tool for districting in other organizations and fields of application. Manuscript profile

امروزه دغدغه های مدیران در پروژه های نفت،گاز و پتروشیمی،تکمیل پروژه ها در موعد مقرر با بالاترین سطح کیفیت اجرای فعالیت ها، صرف کمترین هزینه های مالی و کمترین اثرات مخرب زیست محیطی می باشد. از این رو برقراری موازنه بین چهار هدف متضاد زمان، هزینه،کیفیت و اثرات زیست محیطی از اهمیت ویژه ای برای مدیران برخوردار است. با نگاهی عمیق تر به اهداف مذکور مشخص می شود تمرکز بر روی هر کدام از اهداف چهارگانه منجر به ایجاد تغییراتی بر روی سایر اهداف خواهد شد به عبارتی دیگر بین اهداف مذکور تناقض وجود دارد. به همین منظور در این مطالعه سعی شده است مدلی ریاضی برای موازنه اهداف چهارگانه ارائه گردد که خواسته ها و نیازهای مدیران پروژه را برآورد سازد و به مسائل دنیای واقعی نزدیکتر باشد. مدل ارائه شده از نوع مدل ریاضی چند هدفه صفر و یک است که در این مدل فعالیت های پروژه دارای ماهیتی چند حالته و غیرقابل انقطاع هستند و ظرفیت منابع محدود و مشخص و روابط پیش‌نیازی فعالیت ها از نوع روابط پیش‌نیازی کلی در نظر گرفته شده است. جهت اعتبارسنجی، مدل پیشنهادی با استفاده از نرم افزار GAMS و حل کننده CPLEX توسط روش محدودیت اپسیلون توسعه یافته بر روی داده های واقعی یک پروژه نفتی حل شده و جواب بهینه آن به دست آمده است و نتایج حاصل از تحلیل حساسیت های مختلف گزارش شده است. Manuscript profile