فهرست مطالب
مجله مهندسی صنایع و مدیریت شریف
سال بیست و نهم شماره 1 (بهار و تابستان 1392)
- تاریخ انتشار: 1392/09/18
- تعداد عناوین: 12
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صفحات 3-11این مقاله یک مدل ریاضی جدید و کاملا نوآورانه برای تحلیل اثرات میزان تقلیدپذیری نوآوری بر میزان تولید و تقلید نوآوری، و نیز بر میزان رفاه اجتماعی حاصل از نوآوری ارائه می کند. هسته ی اصلی این مدل، رقابت بین دو بنگاه است که هر دو توانایی خلق نوآوری و نیز توانایی تقلید آن را دارند. هدف، بررسی اثر پارامترهای مختلف بر تصمیم گیری دو بنگاه در رابطه با میزان تولید و میزان تقلید نوآوری است. نتایج حل مدل نشان می دهد که هزینه های تقلید بالا)کم تر تقلیدپذیر بودن نوآوری(نه تنها تولید نوآوری را زیاد می کند، بلکه می تواند تقلید نوآوری را هم افزایش دهد. به کمک مدل، سیاست حق انحصاری نوآوری نیز مورد تحلیل قرار گرفته است. نتایج تحلیل مدل نشان می دهد برای نوآوری های بسیار تقلیدپذیر، اعمال سیاست حق انحصاری موجب افزایش رفاه می شود. به خصوص اگر قیمت فروش نوآوری به میزان کم تر از هزینه ی تمام شده ی نوآوری تعیین شود.
کلیدواژگان: تولید و تقلید نوآوری، رفاه اجتماعی، بنگاه، تقلیدپذیری، سیاست حق انحصار -
صفحات 13-21هدف این مقاله بررسی قابلیت پیاده سازی استراتژی ناب چابک در سازمان های خدمات انبوه و حرفه یی، و مقایسه ی آن ها با یکدیگر است. برای بررسی این موضوع از روش مطالعه ی موردی استفاده شده است. بدین منظور، یک رستوران فست فود زنجیره یی به عنوان سازمان خدمات انبوه، و یک بیمارستان تک تخصصی به عنوان سازمان خدمات حرفه یی از طریق مصاحبه مورد مطالعه قرار گرفته اند. به منظور نشان دادن فرایندها از ابزار نقشه برداری فرایند استفاده شده است. نتایج حاصله حاکی است که رویکرد ناب چابک در این دو نوع سازمان خدماتی قابلیت پیاده سازی دارد. با وجود این که پیاده سازی این استراتژی در رستوران زنجیره یی مشابه بخش ساخت است، اما در بیمارستان مورد مطالعه، به دلیل اهمیت مفاهیم دیگری از قبیل مدیریت موجودی، تا حدودی متفاوت است.
کلیدواژگان: ناب، چابک، ناب، چابک، خدمات انبوه، خدمات حرفه یی -
صفحات 23-31پیچیدگی تصمیم گیری در زنجیره های عرضه باعث نیاز روزافزون به روش هایی برای مدل سازی این سیستم ها شده است. بسیاری از بنگاه های تولیدی و بازرگانی به دنبال مدل هایی هستند که به شناسایی رفتار بنگاه های زنجیره در شرایط مختلف و تصمیم گیری برای بهبود عملکرد آن ها کمک کند. این نوشتار روشی آماری برای مدل سازی و ارزیابی عملکرد یک بنگاه زنجیره ی عرضه پیشنهاد می کند. هدف از به کارگیری این روش، شناخت عوامل کلیدی تاثیرگذار بر عملکرد سیستم و پیش بینی رفتار آن در شرایط مختلف است. در این نوشتار دو معیار عملکرد پیشنهاد و رابطه ی آماری هریک، با عوامل موثر بر عملکرد سیستم تعیین می شود. روابط کمی به دست آمده یک چارچوب تصمیم گیری برای بهبود عملکرد سیستم در راستای راهبردهای رقابتی کل زنجیره فراهم می کند. کاربرد روش پیشنهادی در دنیای واقعی با یک مطالعه ی موردی نشان داده می شودکلیدواژگان: زنجیره ی عرضه، رگرسیون، رگرسیون ریج
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صفحات 33-42زمان رسیدن وسایط نقلیه ی امدادی یکی از مهم ترین پارامترها در مسئله ی پوشش مجموعه در حوزه ی امدادرسانی است. با توجه به مسائل دنیای واقعی، و از آنجا که هر نوع تسهیلی همیشه به طور قطعی در دسترس نیست، در این نوشتار ارائه ی روشی مناسب برای مکان یابی بهینه ی مراکز امدادی با توجه به قیود هزینه ها هدف گیری شده است. با استفاده از سیستم های صف ناپایدار و همچنین زمان مبنا بودن (متغیربودن) نرخ های حوادث و امدادرسانی، مسئله ی پوشش مجموعه بسط داده شده است. به منظور حل این مسئله در ابعاد بزرگ روش بهبودیافته ی بهینه سازی انبوه ذرات (I P S O) و الگوریتم شبیه سازی تبرید (S A) استفاده می شود. به منظور نشان دادن کارایی الگوریتم های پیشنهادی، تعدادی از مسائل در ابعاد کوچک توسط این الگوریتم ها حل و سپس نتایج مربوطه با نتایج حاصل از روش حل دقیق شاخه و کران مقایسه می شودکلیدواژگان: مسئله ی پوشش مجموعه، وسایط نقلیه امدادی، سیستم های صف ناپایدار، الگوریتم بهینه سازی بهبود یافته ی انبوه ذرات، الگوریتم شبیه سازی تبرید
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صفحات 43-52امروزه، رقابت جهانی به دلیل تغییرات سریع تکنولوژیکی و ازدیاد و تنوع محصولات افزایش سریعی پیدا کرده است. این امر باعث تاکید بر نقش بهبود مستمر عملکرد به عنوان یک نیاز رقابتی و راهبردی در بسیاری از سازمان ها در سراسر دنیا شده است. گسترش مشخصه کیفیت به عنوان ابزاری قدرت مند برای بهبود کیفیت و طراحی محصول و ایجاد یک سیستم کیفیت مشتری مدار محسوب می شود. در این پژوهش، یک چارچوب ترکیبی از گسترش مشخصه های کیفیت و برنامه ریزی آرمانی برای نشان دادن سطح برآورد هریک از نیازهای فنی محصول ارائه شده است. در این چارچوب برای به هنجار کردن خانه ی کیفیت از رابطه ی واسرمن استفاده شده است. با توجه به این که رویه ارائه شده، قادر به در نظر گرفتن ماهیت چندمنظوره ی مسئله است، اهدافی همچون افزایش سطح رضایت مشتری، کاهش هزینه و کاهش سختی کار لحاظ شده است. این چارچوب در نهایت در شرکت سیمان لارستان به کار گرفته شده است.
کلیدواژگان: گسترش مشخصه های کیفیت، خانه ی کیفیت، اعداد فازی مثلثی، برنامه ریزی آرمانی -
صفحات 53-62«چیدمان تسهیلات» مسئله یی است که به تعیین موقعیت دپارتمان ها در کف کارخانه می پردازد. رایج ترین هدف در این مسئله کمینه سازی هزینه های حمل ونقل مواد است. بیشتر محققین به چندمنظوره بودن ماهیت مسائل چیدمان اذعان دارند و بنابراین، در تعیین مکان مناسب تسهیلات در نظر گرفتن اهداف مختلف ضرورت می یابد. از این رو در این نوشتار با در نظر گرفتن اهداف مختلف و به کارگیری یک رویکرد چندمرحله یی ٓشامل الگوریتم ژنتیک، الگوریتم -o p t2 و شیوه ی تحلیل پوششی داده هآ یک چیدمان کارا برای مسئله ی چیدمان مبتنی بر ساختار نواری منعطف تعیین می شود. در این نوع چیدمان، دپارتمان ها به صورت پیوسته به نوارهایی موازی با عرض های مختلف اختصاص می یابند. رویکرد پیشنهادی برای چندین مسئله ی موجود در ادبیات موضوع آزمایش شده است. نتایج به دست آمده نشان گر موثربودن رویکرد پیشنهادی است.
کلیدواژگان: مسئله ی چیدمان تسهیلات، ساختار نواری منعطف، الگوریتم ژنتیک، تحلیل پوششی داده ها، الگوریتم، o p t2 -
صفحات 63-70تغییرپذیری در سفارشات یا موجودی های زنجیره های تامین به طور کلی توسط عوامل خارجی ٓمانند عدم اطمینان در تقاضای مشتری یا زمان انتظارٓ ایجاد می شود. مطالعات نشان می دهد که حتی اگر این عوامل قطعی باشند، سفارشات یا موجودی ها مقداری تغییرپذیری را نشان می دهند. در این نوشتار، نشان می دهیم که در یک زنجیره ی تامین کلاسیک توزیع نوشیدنی چگونه این تغییرپذیری ممکن است به صورت هزینه ی کل و اثر شلاقی اتفاق بیفتد، و به منظور مدیریت بهتر عامل ها برای کاهش پویایی پیشنهاداتی ارائه خواهد شد. در این مدل مشاهده می شود پویایی های زنجیره تحت تاثیر عامل های گوناگونی همچون: الگوی تقاضا، سیاست سفارش دهی، به اشتراک گذاشتن اطلاعات تقاضا و زمان انتظار قرار دارد. بررسی تاثیرات این عامل ها بر پویایی زنجیره، با استفاده از طرح فاکتوریلی، نشان می دهد «سیاست سفارش دهی» مهم ترین عامل در پویایی زنجیره محسوب می شود و با توجه به نوع الگوی تقاضا می توان با انتخاب نوع سیاست سفارش دهی شاهد کاهش پویایی زنجیره بود.
کلیدواژگان: مدیریت زنجیره ی تامین، بازی توزیع نوشیدنی، پویایی سیستم، اثر شلاقی، طرح فاکتوریل -
صفحات 71-76اغلب مطالعات انجام شده در زمینه ی تبلیغات و استراتژی های زنجیره ی تامین، یک سازنده و یک خرده فروش را شامل بوده است. در این تحقیق سیاست های قیمت گذاری و تبلیغات سه سطحی بین یک سازنده، یک توزیع کننده و یک خرده فروش مورد بررسی قرار گرفته است و شامل دو فاز تبلیغات مشارکتی و تبلیغات غیرمشارکتی با تابع تقاضای حساس به قیمت است. نتایج به دست آمده از این تحقیق نشان می دهد که سود زنجیره ی تامین سه سطحی زمانی که در تبلیغات بین اعضاء مشارکت وجود دارد بیشتر از تبلیغات در وضعیت غیرمشارکتی است. با ورود یک توزیع کننده با قابلیت تبلیغات به زنجیره ی تامین، سود سازنده در تبلیغات غیرمشارکتی کاهش می یابد، ورود سایر اعضای زنجیره ی تامین به برنامه ی تبلیغات مشارکتی امری ضروری برای بقاء و حفظ سود سازنده در کل زنجیره ی تامین است.
کلیدواژگان: تبلیغات مشارکتی، زنجیره ی تامین سه سطحی، معادله استکلبرگ -
صفحات 77-86متحرک سازی تسهیلات که یکی از اصول مکان یابی در پدافند غیر عامل است از مسائل نوین مطرح شده در مکان یابی مطرح شده است. در این نوشتار دو مدل برای کمینه کردن جابه جایی ها در شبکه یی پیوسته از مشتریان و تسهیلات متحرک طراحی و توسعه داده شده است. در هر دو مدل ضمن تعریف متغیرهای بیان گر تحرک تسهیلات و مشتریان، پارامتر تقاضا برای هریک از مشتریان، و پارامتر ظرفیت برای تسهیلات شبکه در نظر گرفته شده است. در مدل دوم پارامتر وزن (اهمیت) افزوده شده است. مدل های ارائه شده با استفاده از نرم افزار G A M S اعتبارسنجی شده، سپس مثال های عددی و ترسیمی از آن ها معرفی شده است. نوآوری مدل دوم (توسعه مدل اول) نسبت به مسائل کلاسیک متحرک، وابستگی حل مدل به حرکت نقاط بدون در نظر گرفتن متغیر زمان است.
کلیدواژگان: تسهیلات متحرک، مشتریان متحرک، شبکه ی پیوسته، پدافند غیر عامل -
صفحات 87-100مهندسی صنایع به عنوان یکی از رشته های نسبتا جدید در طول سال های اخیر، تغییرات قابل توجهی داشته و در شاخه های متنوعی توسعه یافته است. از این منظر پیش بینی روند پژوهش های آتی در مهندسی صنایع براساس مقالات علمی انتشار یافته اهمیت دارد. بدین منظور تعداد 87150 مقاله مرتبط با رشته ی مهندسی صنایع ٓکه در 50 سال اخیر در 54 نشریه ی بین المللی منتشر شدهٓ مورد تحلیل قرار گرفت. از آن تعداد 347 واژه ی کلیدی اصلی و 280 دپارتمان و 101 نام کشور محل انتشار استخراج شد. با تحلیل روند 50 سال گذشته روند 10 سال آینده با روش سری زمانی پیش بینی شد. بررسی روند پژوهش ها در گذشته نشان می دهد که بیشترین تعداد مقاله بر موضوعات سیستم های هوشمند و اطلاعاتی، برنامه ریزی و نظریه ی سازمان، تکنیک های تجزیه و تحلیل و تحقیق در عملیات معطوف است. از نظر منطقه یی، کشورهای آمریکای شمالی، آسیای شرقی و اروپای غربی بیشترین تعداد انتشار مقاله را به خود اختصاص داده اند. براساس پیش بینی صورت گرفته در این پژوهش، موضوعات سیستم های هوشمند و اطلاعاتی، تکنیک های تجزیه وتحلیل و تحقیق در عملیات و مناطق آسیای شرقی و اروپای غربی بیشترین تعداد در انتشار مقالات را خواهند داشت.
کلیدواژگان: پژوهش، مهندسی صنایع، روند، موضوعات پژوهشی، سری زمانی -
صفحات 101-111در این تحقیق مدلی جدید برای سیستم موجودی بازدید پیوسته چندمحصولی با محدودیت های فضای انبار، بودجه و کم ترین سطح خدمت در حالت کمبود پس افت جزئی ارائه شده است. هدف به دست آوردن مقدار سفارش و نقطه سفارش مجدد است به گونه یی که هزینه ی کل سالیانه کمینه شود. این مدل با روش آزادسازی لاگرانژ و ترکیب آن با الگوریتم ابتکاری شناخته شده هدلی ویتین برای مسائل با ابعاد کوچک، و روش فراابتکاری شبیه سازی تبرید برای مسائل با ابعاد بزرگ حل می شود. از آنجا که روش آزادسازی لاگرانژ اجزء روش های دقیق است، می توان از آن برای ارزیابی جواب روش شبیه سازی تبرید بهره برد. مقایسه جواب های به دست آمده از دو روش نشان می دهد که روش شبیه سازی تبرید کارایی مناسب و قابل قبولی برای حل مدل پیشنهادی دارد.
کلیدواژگان: کنترل موجودی بازدید پیوسته، کمبود پس افت جزئی، محدودیت فضای انبار، محدودیت بودجه، محدودیت کم ترین سطح سرویس -
صفحات 113-121در سال های اخیر اهمیت داده ها به عنوان منابع دارای پتانسیل اطلاعاتی بسیار بالا به نحو گسترده یی مورد توجه قرار گرفته شده است. داده کاوی با استخراج و کشف سریع و دقیق اطلاعات با ارزش و پنهان از پایگاه داده ها به منظور تصمیم گیری و پشتیبانی تصمیم از جمله اموری است که هر کشور، سازمان و شرکتی به منظور توسعه علمی، فنی و اقتصادی خود به آن نیاز دارد. با توجه به ضرورت استفاده از فنون داده کاوی ٓخصوصا خوشه بندیٓ در این نوشتار یک مدل ریاضی براساس رویکرد خوشه بندی ارائه می شود که در خوشه بندی مشتریان شرکت صنعتی پارس خزر کاربرد دارد. مسئله ی خوشه بندی به صورت مدل ریاضی با هدف کمینه سازی مجموع متوسط فواصل درون خوشه یی در طبقه بندی مشتریان فرمول بندی می شود که در تمامی موارد آزمایش شده، با بهبودبخشی شدید در فواصل درون خوشه یی همراه است. عملکرد این شیوه در یک مسئله ی واقعی آزموده شده و تحلیل نتایج حاکی از کارایی محاسبات این شیوه است.
کلیدواژگان: داده کاوی، خوشه بندی، روش های خوشه بندی سلسله یی و غیرسلسله یی، مدیریت ارتباط با مشتری، الگوریتم k، m e a n s
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Pages 3-11The tradeoff between innovation development and innovation imitation has been widely studied in the literature of technology diffusion. In this paper, a mathematical model is developed to investigate how innovation imitability affects the amount of developed innovations, imitated innovations and, also, social welfare, resulted from innovations. For the sake of simplicity, it is considered that there are two firms producing the same product with the same price in the market and with equal market shares, while their production costs are different. The market is assumed competitive, thus, the cost reduction of one firm results in lower prices and, consequently, less profit for the other firm. As obvious in the model, the problem is captured by linking the production cost of one firm to the profit of the other firm. By the aid of this model, we have presented barriers to innovation development and diffusion. The model is based on competition between two firms in the context of a strictly competitive game, and both are able to develop and imitate innovations simultaneously. The greatest challenge in this model is to understand how firms endogenously decide on, not only how much innovation to develop, but, also, how much innovation to imitate. The results of the model solution point out that higher imitation costs (less imitability) not only increase innovation development, but, also, may increase innovation imitation. We have further used the model to investigate the effectiveness of an apparently anti-innovation imitation policy: Intellectual Property Right (IPR). This is a routine policy which governments can easily consider toward innovation imitation between firms. Two points considered are: First, how the policy is modeled and entered into the model equations, and, second, how that policy affects the solution results. The main criteria for investigating this effects of this policy is its effect on social welfare resulting from innovations. While the IPR policy is implemented, developed innovations are available in the market for other firms to be used. However, firms have to pay a pre-determined amount of money to the innovation developer firm. This policy changes to parts of the model: firstly, the imitation cost increases as much as the innovation buying price, and, secondly, the indirect costs of the innovation developer firm decreases. Whether it is the first or the second firm, the same changes happen to the innovator and imitator firms. Solution results bear the testimony that for highly imitable innovations, implementing IPR results in higher social welfare, especially if the price of buying that innovation is set to an amount less than the cost of developing that innovation.Keywords: Innovation development and imitation, social welfare, firm, imitability, intellectual property rights
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Pages 13-21Leanness and agility have their particular advantages, and each one can be applied to different situations. During the last decade, there have been some efforts to benefit from both strategies. Leagility is a concept aimed at combining lean and agile supply chains. This research aims to show how leagility can be applied and implemented in the service sector (mass and professional services). To this aim, a case study approach is used. Therefore, a fast food restaurant chain and a specialized hospital, as mass and professional service organizations, respectively, have been studied, using interviews, observation and documents. Moreover, in order to illustrate the processes, a process mapping tool has been utilized. The results indicate the possibility of the application of leagility in these two types of service. Although it may be criticized that mass services have low customization and that leagility cannot be applicable to this area, in recent years, mass services like fast food restaurants have faced problems about variety. Therefore, it is necessary to change the attitudes and views about this type of service. This research shows that the case organization as a mass service provider can benefit from both lean and agile strategies in its supply chain, so that costs can be reduced and, at the same time, the fluctuating demand of the customers can be responded to. The particular situation of the studied hospital has also forced it to be both agile and lean. It is discussed that the geographically strategic location of the healthcare center contributes to both leanness and agility. The information gained from interviews signifies education and job experience as important factors for agility in healthcare services. Therefore, the center has invested on these factors. Another achievement toward agility is the healthcare information system, which has led to reduced lead time and flexibility in the case organization. While the decoupling point is the main concern in leagility, the location of the decoupling point in this healthcare supply chain is discussed. Therefore, the healthcare services are first divided into three pipelines. It is, then, argued that the main decoupling point is located at the point of diagnosis, from which, from this point on, the treatment process is customized for each patient. Another decoupling point is further identified for the secondpipeline. In this way, the lead times and costs would be reduced, so that the specialist's time would be free enough to take care of more patients. The research findings also imply that although the implementation of leagility in fast food restaurant chains is similar to the manufacturing sector, it is different in the studied hospital, as some other concepts, like capacity management, play an important role. This study just focuses on one fast food restaurant chain. It does not consider fast food restaurants with one branch, which may not have the problems associated with restaurant chains. The research also considers a specialized healthcare center with limited pipelines. For further study, it is important to consider a generalized hospital with multiple pipelines. In addition, to make the findings of this research more robust, other areas of mass and professional service can be investigated. Study of the third type of service is also out of the scope of this research.Keywords: Lean production, agile production, leagility, mass services, professional services
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Pages 23-31The complexity of decision making in supply chain management has resulted in a growing need for modeling methodologies. A large number of production and distribution firms are looking for models that can help identify firm performance and make decisions for improvement. In this paper, a systematic procedure to model and evaluate the operating performances of a supply chain, in terms of both efficiency and effectiveness, using a ridge-regression approach is first proposed. The goal is to identify significant factors affecting firm performance and to predict system behavior under different operating conditions. The statistical relations of the performance measures with significant factors are then determined. These relations provide a decision-making framework to improve system performances within the competitive strategy of the whole supply chain. The simplicity and less time requirement of the proposed approach compared to other approaches, such as discrete and continuous simulation, as well as its clear conclusions and its applicability to different supply chain systems, make the proposed methodology more appealing. Finally, a real-world application of the proposed methodology is demonstrated through a case study. Although the results are applicable to the system under consideration, the proposed methodology can be easily adapted to other real-world supply chain systems.
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Pages 33-42Set covering problems have attracted a great deal of attention by researchers in recent years, especially in emergency systems. One of the most important objectives in set covering problems is for emergency vehicles to be on time at accident locations in order to provide services. Based on real observations, service facilities (i.e., emergency vehicles) are not always available, and are provided in an uncertainty condition. Regarding these problems, after defining customer location, facility centers are selected from candidate points to present services to customers efficiently. Hence, an appropriate method is investigated to localize emergency centers, so that accident locations receive appropriate services. In this paper, a new approach, based on queuing systems, is presented for developing set covering problems, in which the arrival rate of the emergency services and service rate vary at different time intervals, as shown by $lambda(t)$ and $mu(t)$, respectively. These are categorized as non-stationary queuing systems with time-varying rates, which is a probability variable, depending on the traffic conditions, accidents, weather conditions, failure of vehicles, and condition of routes, and so on. To approximate arrival and service rates innon-stationary M(t) /M(t) /1 queuing systems, their average rates can be considered to determine the probability of available facilities. Since exact solutions of the set covering problems that belong to the category of NP-hard problems are not practical on a large scale, two meta-heuristic algorithms, namely; Improved Particle Swarm Optimization (IPSO) and Simulated Annealing (SA), are presented, and the results are compared with the branch and bound algorithm in small size problems. At the end, a number of test problems in large scale are solved, and the efficiency of the foregoing algorithms is evaluated. The results have shown that IPSO obtained high quality solutions with a reasonable computational time and accuracy, rather than the SA algorithm.Keywords: keywords{Set covering problem, emergency vehicles, non, stationary queuing systems, particle swarm optimization, simulated annesling
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Pages 43-52Today, universal competition has greatly increased, due to the rapid change in technical progress and the variety of production. This makes the role of Performance improvemen as a computational and strategic requirement in many organization worldwide. The function of production is in the area of engineering characteristics, and, for this design, correct understanding of customer requirements and recognition of design requirements are important. Quality function deployment is a strong instrument for improving the quality and design of a product and for making a system customer oriented. In this research, we have combined a frame of QFD and GP for showing the fulfillment level of DR(s). Waserman's has been used in the frame for normalizing houses of quality. This framework can include multi goals, like increasing customer satisfaction, and decreasing costs and technical difficulty. Suppose that customer satisfaction and cost expenditure are considered more important than technical difficulty (two such priority levels are recommended in the QFD process). Based on the three fuzzy goals and their preemptive priority structure, the overall model can be formulated. Determining goal values precisely is difficult for the design team. Since customer satisfaction, cost, and technical difficulty are not easy to measure exactly, these goals usually conflict with each other. For dealing with this, the design team first determines aspiration levels for each goal, and then finds a set of solutions to achieve the maximum satisfaction degree of all goals in total. The important variable in this model is $x_{j}. x_{j}$ is the fulfillment level of engineering design requirement, j =1,2,... n. if $x_{j}$ = 100%, it denotes complete fulfillment of the objective targets for the jth DR. For solving this problem, the model transforms with fuzzy coefficients to a family of conventional crisp mathematical programming models by applying the $alpha-cut$ approach and Zadeh's extension principle. Obviously, if a designer requires more information to decide the fulfillment level of DRs, more $alpha-cut$ are needed. Different $alpha$ values lead to different ranges of degree satisfaction of the goals and also those of the fulfillment levels of DRs. The membership function for fuzzy goals and fuzzy fulfillment levels are constructed by piecewise linear segments based on different $alpha$ values Finally, this research has been used in the Cement Company of Larestan, Iran, producing Portland II cement.Keywords: Quality function deployment, house of quality, fuzzy number, fuzzy goal programming
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Pages 53-62The facility layout problem (FLP) involves determining the position of department plant floors. The most common objective in this problem is minimizing material handling costs. This paper presents a multistage approach for the facility layout problem based on flexible bay structure. This structure, proposed by Tong (1991) for the first time, is the limited state of the continuous layout problem. In a plant layout, based on flexible bay structure, departments are assigned to parallel bays on a plant floor. Departments could be free oriented and may have unequal areas. The width of each bay is flexible and dependent on the number of departments located in that bay. The width of each bay is obtained by dividing the area of departments located in the bay by minimum sides of the plant floor. In addition, the numbers of bays and departments set in each bay are changeable or flexible. It should be noted that in problems based on flexible bay structure, due to control department shapes, the factor of the maximum aspect ratio is used. Due to complexity, only small-size problems could be solved in logical time, while using exact methods. Thus, at the first stage, a genetic algorithm (GA) was proposed to solve this optimization problem. Genetic algorithms are meta-heuristic methods for solving problems based on evolution mechanisms and the nature of genes. The main idea in this regard was introduced by Holland in 1975, and for three decades has been introduced as an effective optimization and search method. In the genetic code used in this paper, each chromosome is formed by N genes, each of which is a random number between 1 and B, the integer part of which represents the number of bays, and the decimal part of which represents the department sequence in each bay. The proposed GA algorithm uses FBS to represent the facility layout with the unequal area department. The proposed algorithm tries to find the optimum value for the number of bays, the number of departments contained in each bay, and the department's placement order, which could minimize the objective function value. The majority of researchers believe that the facility layout problems are naturally multi-objective. Therefore, considering various objectives in determining the proper position of facilities is essential. The proposed approach is that, after creating a primary layout using the genetic algorithm, a 2-opt algorithm has been applied to generate layout alternatives. Then, using the DEA approach, the most efficient layout from alternatives will be chosen. This paper improves the integrated data envelopment analysis (DEA) model introduced by Amin (2009) for finding the most efficient decision making units. The proposed approach was tested on some test problems of the FLP literature. The results show the effectiveness of the proposed algorithm.Keywords: Facility layout problem, flexible bay structure, genetic algorithm, data envelopment analysis, 2, op
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A N A L Y S I S O F SU P P L Y C H A I N D Y N A M I C S I N B E E R D I S T R I B U T I O N G A M EPages 63-70In a supply chain, the variability of orders can be more than the variability of demand, and this phenomenon is known as the bullwhip effect. Managers of supply chains have experienced this phenomenon in their orders and inventory levels. Variability in orders or inventories in supply chains is generally thought to be caused by exogenous random factors such as uncertainties in customer demand or lead time. According to performed studies that have been done in this area, however, orders or inventories may exhibit significant variability, even if customer demand and lead time are deterministic. On the other hand, the decrease of order variability, due to an increase in inventory variance, has a negative effect on the level of customer service. Due to this weighty matter, in this paper, we show that how this variability; dynamism, may occur in a four-level supply chain (A retailer, a wholesaler, a distributor and a manufacturer) as total cost and bullwhip effect, and offer insights into how to manage relevant supply chain factors to eliminate or reduce system dynamics. The supply chain is characterized by the classical beer distribution model with some modifications, including changes in demand, information and ordering policy. In this model, we observe the supply chain dynamics under the influence of various factors: demand pattern, ordering policy, demand-information sharing, and lead time. The effects of these factors on the chain dynamics using factorial design show that the ordering policy factor is considered the most in chain dynamics, while information sharing and lead time factors are not, respectively, effective on total cost and bullwhip effect. Therefore, the factors, information sharing at high level for decrease in bullwhip effect, and lead time at low level for decrease of total cost, are considered constantly. Thus, according to the type of demand pattern, chain dynamics can be reduced with laying to a selection of ordering policy type.Keywords: Supply chain management, beer distribution game, system dynamics, bullwhip effect, factorial design
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Pages 71-76Cooperative advertising is an important instrument for aligning decisions in supply chains, and research on it has been continuously active over the last decade. In this paper, we have studied effects of coordination of cooperative advertisement on the profit of all members of a supply chain. The study consists of a three level supply chain; one manufacturer, one distributor and one retailer, with cooperative and non cooperative advertising schemes. The study is conducted in two phases. In phase one, the effect of a non-cooperative advertising scheme on the profit of all parties is studied. The optimal value of the decision-making variables is determined using Stackelberg equilibrium. In this phase, the optimal value of advertisement expenditures of the manufacturer, distributer and retailer and their selling prices were determined. In the second phase, the effect of a cooperative advertising scheme on the profit of the supply chain members is modeled and, by solving the equations, the optimal value of advertisement expenditure and selling prices of the manufacturer, distributer and retailer were obtained. The sensitivity of the model was tested using a numerical example. It was shown that the total supply chain profit in cooperative advertising is higher than in a non-cooperative scheme. The result of the study gives a clear picture of the competition and cooperative advertising strategies between channel members. It was found in the none-cooperative advertising scheme that the retailer attempts to increase his profit by increasing his selling prices in higher advertisement expenditure. The leader (manufacturer), will always push the follower (the retailer or the distributor) to have more expenditure in the advertisement. In this case, the retailer defrays more advertising expenditure and, due to higher retail prices, his profit is higher than other parties. In summary, it was found that coordination in the advertisement expenditure increases the profit of all supply chain members. Therefore, to increase the profits of all parties in a supply chain, we recommend cooperative advertising, with a partnership relationship between manufacturer, distributer and retailers.Keywords: Supply chain, cooperative advertising, marketing channels, Stackelberg equilibrium
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Pages 77-86In general, moving issues achieve an overall purpose in a network by the use of coordinate movements of a collection of objects. Since, today, technological progress is so fast, access to activities that are concerned with parameters, such as ways of saving cost, time, and displacement, require a definition for customers, to facilitate moving variables and restrictions in the network to achieve the networks purpose. This study developed a model aiming to minimize movement in locating mobile facilities and to provide service for high-priority clients in a given network composed of clients and mobile facilities, bearing two parameters in mind: the capacity of facilities and client priority. The validity of the model was then put to test applying GAMS software, and, thereafter, two numerical and graphical instances were introduced. Moving issues of mobility facilities is a new issue that has been raised in location finding. In this study, two models are designed and developed in order to minimize movement in a continuous network of customers and mobile facilities. In the presented models, the purposes are found with regard to some of the limitations in the network, such as capacity of each facility, and the importance and weight of each customer. In the first model, after defining variables that determine mobility facilities and customers, and considering request parameters for each customer, the parameter as a network facility capacity has been considered. Then, in order to define this parameter, limitation has been considered, which is obliged to not exceed the total facility capacity of total customer demand. The second model is designed considering parameters and variables as the previous model. Moreover, we find important parameters or weights of each network customer with the aim to serve customers with higher priority, in addition to minimizing movement. Then, the presented models have been validated and analyzed by the use of GAMS software. The number of network nodes, customer demand, facility capacity and node distance from each other are the parameters which the model has analyzed on the basis of their change. The innovation of the second model (development of first model) in comparison with Mobile Classical Problems is that solving the model contributes to the movement of points (vertexes), without any consideration of the time variable. The results found after analyzing the presented models are an increase in problem solving time with an increase in the number of nodes in both model, and the solvability of the second model because of the number of nodes being more than the first model, due to a virtual node.Keywords: mobile facility, mobile customer, continuous network, movement, analysis, GAMS software
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Pages 87-100Industrial engineering is a relatively new field among engineering disciplines, which has been developed during recent decades. Therefore, the prediction of the trend of industrial engineering research is important, as it provides valuable information for future work in this field. The aim of this paper is to analyze recent trends, as well as future perspectives of industrial engineering research. For this purpose, 87150 papers related to industrial engineering, which have been published over the last 50 years, were selected from 54 journals. The required data, including 347 keywords, 280 departments and 101 countries, relating to these papers were recorded in a database. The keywords were classified into 14 main topics, based on categorization of the AmericanInstitute of Industrial Engineering. The extracted departments were clustered into 12 groups. The clusters were Industrial Engineering, Business, Management, Computer and Information Technology, Mechanical Engineering, Mathematics and Statistics, Electronics Engineering, Economics, Accounting, and other departments and research institutes. In analyzing the countries, papers were categorized according to 9 world regions; Africa, Central and South America, North America, Eastern Europe, Western Europe, Scandinavia, Eastern Asia, Western Asia and Oceania. The published papers during the last 50 years were analyzed and a prediction was made for the 10 coming years, using the time series method. ARIMA models were used for analysis with different parameters. According to the descriptive statistics analysis, the most popular subjects wer ``Information and Intelligent Systems'', ``Planning and Organization Theory'' and ``Analysis Techniques and Operations Research''. The most interdisciplinary subjects of the papers were ``Planning and Organization Theory'', ``Information and Intelligent Systems'' and ``Analysis Techniques and Operations Research''. In a regional view, most of the published papers were from North America, East Asia and west Europe. The rank of Iran in all subjects was 23 cumulatively. According to forecasting, the topics of ``Information and Intelligent Systems'' and ``Analysis Techniques and Operations Research'' and ``Planning and Organization Theory'' will be more favorable in the near future, and regional countries of East Asia, Western Europe and North America will have the highest publication. Regarding interdisciplinary subjects, ``Planning and Organization Theory'', ``Information and Intelligent Systems'' and ``Analysis Techniques and Operations Research'' will have the highest demand.Keywords: Research, industrial engineering, trend, research topics, time series analysis
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Pages 101-111Recently, different inventory models have been widely used in production and sales. However, some assumptions of these models do not provide the possibility of their use in practice. Therefore, it seems necessary to put aside these assumptions and expand the existing models. The most popular of these models is the classical economic order quantity (EOQ) that appears in every basic textbook covering inventory management. A key assumption of the basic EOQ model is that the demand is certain, so shortage is not permitted. While, in the real world, usually, demand is probabilistic, so, there is the possibility of encountering shortages. In some real life situations, there is a part of demand that cannot be satisfied from the current inventory, leaving the system in stock out. In these systems, two situations are mainly considered: all customers wait until the arrival of the next order (complete back order case) or all customers leave the system (lost sales case). However, in practical, some customers are able to wait for the next order to satisfy their demands during the stock out period, while others do not wish to, or cannot wait, and they have to fill their demands from other sources. This situation is modeled by consideration of partial backlogging in the formulation of the mathematical model. Therefore, In general, three approaches, including backorder, lost sales and partial backlogging, are considered when faced with shortage. In backorder models, the answer to all demands is commitment, in lost sales, there is no commitment to demand, and, in partial backlogging, a portion of the demand is backlogged. In partial backlogging, some customers are willing to wait for delivery, others are not. A common characteristic of this model is the assumption that the percentage of orders arriving during the shortage period that will be backordered is exogenously determined. Either these customers will cancel their orders or the supplier will have to fill them within the normal delivery time by using more expensive supply methods. Another major problem in traditional inventory models is restrictions in real world constraints, such as budget constraint, space constraint, number of orders constraint, service level constraint and etc. This applies more particularly to shortage models. Work on inventory control models, especially continuous models, pays little attention to constraints. In this survey, a multi product continuous review inventory model with capacitپy warehouse constraints, budget, and minimum service level in partial backlogging, in order to obtain the quantity order and reorder point to achieve minimum total annual cost, is minimized. Lagrangian relaxation and a hybrid heuristic algorithm based on Hadly-Whithin for small size problems, and a simulated annealing (SA) algorithm for large scale problems is used. Since the release Lagrange method is an exact method, to evaluate solutions obtained from the simulated annealing algorithm can be used. Comparison of the results obtained from the Lagrange method and the SA algorithm shows that the SA algorithm is credible and has suitable efficiency.Keywords: Continuous review inventory model, partial backlogging, capacity warehouse constraint, budget constraint, minimum service level constraint
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Pages 113-121In recent years, data importance is widely considered as a resource with high information potential. Data mining is a process of extracting and refining knowledge from a large database. The extracted information can be used to predict, classify, model, and characterize the data being mined. It is an intelligent method of discovering unknown or unexplored relationships within a large database. It uses the principles of pattern recognition and machine learning to discover knowledge, and various statistical and visualization techniques to present the knowledge in a comprehensible form. Data mining with extraction, and rapid and precise discovery of valuable and hidden information from data bases, is used for decision making and decision support. It is a technique that every country, organization and company requires in order for scientific, technological and economic development. Nowadays, considering the strong competition condition of companies and organizations to gain new customers and maintain previous customers, the volume of customer information and dramatically complex interaction with customers, data mining has been a pioneer for acquisition profitability in customer relationships, considering the necessity to use data mining, especially clustering. In this paper, the first concept of clustering and its applications is considered, then a review about data mining mathematical concepts and clustering, including: minimizing the sums of squares within clustering, components related to p-dimension Euclidean space, minimizing the distances of the mean squared sum within clustering, number of clusters, minimizing the total distance within clustering, and minimizing the maximum distance within clusters, is addressed. A model of ``minimizing the mean sum of distances within clusters in customer segmentation'' is proposed. The proposed model is formulated as a mathematical model with the objective of minimizing the mean sum of distances within clusters. Then, the model is compared with the ``minimizing the distances mean squared sum within clustering'' model using MATLAB 7.5.0 (R2007b). The proposed method does not depend on any initial positions for the cluster centers and does not allow any empirically adjustable parameters. In the tested cases, the model has improved the distances within clusters. Finally, the performance of the model is tested on a real problem for classification of the Parskhazar Industry customers. Experiments reveal that the proposed model has efficient yield.Keywords: Data mining, clustering, hierarchical and nonhierarchical clustering, customer relationship management, k, means algorithm
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