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ردیف | عنوان | نوع |
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21 |
Effect of a lead time-dependent cost on lead time quotation, pricing, and capacity decisions in a stochastic make-to-order system with endogenous demand
تاثیر یک هزینه مستقل از زمان سفارش روی خرید و فروش در این زمان، قیمت گذاری و تصمیمات ظرفیتی در یک سیستم تصادفی سفارشی با تقاضای درون زا-2018 The research on lead time quotation in make-to-order stochastic systems with an endogenous demand generally considers a system modelled as an M/M/1 queue with a linear demand that is sensitive to lead time and price, and always assume a constant unit operating cost. It is known that firms can reduce the operating cost by quoting a longer lead time. The idea of this paper stems from this observation. Indeed, we extend the existing works by modelling the unit operating cost, not as a constant, but as a convex decreasing function of the quoted lead time, which significantly rises the analytical difficulty but offers opportunities for many insights. We study three settings: (i) lead time quotation model, (ii) lead time quotation and pricing model, and (iii) lead time quotation, pricing, and capacity decision model. For each setting, we provide the optimal policy and conduct experiments to derive insights. In particular, we analyze the new trade-offs raised by the consideration of a lead time-sensitive cost. Some of our results are not intuitive.
keywords: Lead time quotation |Lead time-dependent cost |Pricing |Capacity |Endogenous demand |M/M/1 queue |
مقاله انگلیسی |
22 |
Balancing and cyclically sequencing synchronous, asynchronous, and hybrid unpaced assembly lines
متعادل سازی و ترتیب بندی چرخه ای خط مونتاژهای ترکیبی و غیر آهنگدار همزمان و غیر همزمان-2018 Mixed-model assembly lines are product-oriented production layouts often employed for large scale manufacturing of similar products. The unpaced variant of these lines employs a conveyor to discretely move pieces between stations either synchronously or asynchronously. Workload balancing and product sequencing are common optimization problems associated with these lines. While many works detail balancing and sequencing separately, few explicitly combine these degrees of freedom. Furthermore, hybrid (i.e. partly synchronous and partly asynchronous) lines are not explicitly described by previous optimization models. This paper presents a mixed-integer linear programming model capable of representing such unpaced lines and explicitly combine balancing, sequencing and cyclical scheduling. The application of the proposed method to a new dataset demonstrates the advantages of simultaneously balancing and sequencing lines, generating more efficient solutions than previously described models for 238 out of 240 instances. These results implied, however, in greater computational costs required to combine the degrees of freedom. Furthermore, a direct performance comparison study between synchronous, asynchronous, and hybrid lines is conducted. This allows line designers and managers to explicitly evaluate economical trade-offs between these line types.
keywords: Unpaced assembly line balancing |Mixed-model sequencing |Cyclical scheduling |Mixed-integer linear programming |
مقاله انگلیسی |
23 |
Big Data versus a survey
مروری بر نقیض داده های بزرگ-2018 Economists are shifting resources from work on survey data to work involving “Big Data.” This analysis
is an empirical exploration of the trade-offs this substitution requires. Parallel models are estimated
using Equifax credit bureau data and Survey of Consumer Finances data. After adjustments to account
for different variable definitions and sampled populations, it is possible to arrive at similar models of
total household debt. However, the estimates are sensitive to the adjustments. In this example, some
external education and income measures are successfully integrated with the big data, but other external
aggregates fail to adequately substitute for survey responses.
Keywords: Big Data ، Survey data ، Household debt |
مقاله انگلیسی |
24 |
Impact of shelf life on the trade-off between economic and environmental objectives: A dairy case
تاثیر عمر طاقچه ای روی سبک و سنگین کردن بین اهداف اقتصادی و محیطی: یک مورد لبنیاتی-2018 Food manufacturers introduce more environmentally friendly processes to account for increasing sustainability concerns. However, these processes often go along with a reduction of product shelf life, limiting the delay of sales to future periods with higher prices. We develop a framework to analyze the impact of shelf life on the trade-off between economic and environmental performance of two types of dairy products. Since the differences in shelf life have their key impact at the tactical planning level, we develop an optimization model for this aggregation level. Its objectives reflect profit and relevant environmental indicators. A rolling horizon scheme is used to deal with price uncertainty, using Eurex futures as price predictors. Our framework uses these tactical planning results for strategic decisions on product and process selection. A real-life case study contrasts traditional milk powders against novel milk concentrates. Concentrates require less energy in processing, but have a shorter shelf life. Results show that powders offer a potential profit benefit of up to 34.5%. However, this economic value of shelf life is subject to a priori perfect price knowledge. If futures are used as price predictors, the value of shelf life is reduced to only 1.1%. The economic value of shelf life is therefore not a strong argument against the substitution of powders with more environmentally friendly concentrates. We also show that two objectives, profit and eutrophication potential, are sufficient to capture trade-offs in the case. Several product mixes are determined that omit powders and perform well with regard to profit and environment.
keywords: Perishability |Sustainability |Multi-objective optimization |Objective reduction |Dairy industry |
مقاله انگلیسی |
25 |
Measuring the impact of enterprise integration on firm performance using data envelopment analysis
سنجش تاثیر یکپارچگی شرکتی روی عملکرد شرکت با استفاده از تحلیل پوشش داده ای-2018 Today, with rapidly developing technology and changing business models, organizations face rapid changes in both internal and external environments. To be able to rapidly respond to such changing environments, integration of software systems has become a top priority for many organizations. However, despite extensive use of software systems integration, quantitative methods for estimating the business value of such integrations are still missing. Using Data Envelopment Analysis (DEA) and the microeconomic concept of marginal rates, this study proposes a method for quantifying the effects of enterprise integration on the firm performance. In the paper, we explain how DEA can be used to evaluate the marginal benefits of enterprise integration. Our proposed method is to measure and compare the productive efficiency of firms using enterprise integration, specifically by relating the benefits produced to the resources consumed in the process. The method is illustrated on data collected from 12 organizations. The defined method has a solid theoretical foundation, eliminating the need for a priori information about the relationship between different measures. Furthermore, the framework could be used not only to quantify the business value of enterprise integration, but also to estimate trade-offs and impacts of other subjective managerial goals on the results. The major limitation of the proposed method is the absence of a comprehensive theory relating IT architecture changes to organizational outcomes. The underlying model is strongly dependent on the relevancy and accuracy of the included variables, as well as number of data units, introducing uncertainties to the outcomes of the model.
keywords: Enterprise integration |Data envelopment analysis |Information technology |Business value |Firm performance |Productivity |
مقاله انگلیسی |
26 |
داده های بزرگ در مقابل مرور
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 12 - تعداد صفحات فایل doc فارسی: 36 اقتصاددانان منابع از کار بر روی داده های نظر سنجی به کاری که شامل داده های بزرگ است؛ جابجا می نمایند. این انالیز در اکتشافات تجربی از معادلات جبران خسارت است که نیاز به جایگزینی دارد. مدل های موازی با استفاده از داده های دفتر اعتباری Equifax و بررسی داده های مالی مصرف کننده تخمین زده می شود. بعد از تنظیمات حساب برای تعریف متغییرهای مختلف و جمع اوری نمونه ها؛ برای برای رسیدن به مدل های مشابه از کل بدهی خانوار امکان پذیر است. با وجود این؛ تخمین ها به تنظیمات حساس هستند. در این مثال؛ برخی از آموزش های خارجی و اقدامات درآمد با موفقیت داده های بزرگ ادغام می شوند، اما سایر ارقام خارجی به درستی جایگزین پاسخ های نظرسنجی نمی شوند.
کلمات کلیدی: داده های بزرگ | داده های مروری | بدهی خانوار |
مقاله ترجمه شده |
27 |
The Hydro-economics of Mining
هیدروکربنهای معدنی-2018 Joint research between economists and hydrologists increasingly contributes to optimising the economic value
gained from water, while safeguarding its social and environmental values. The application of hydro-economic
analysis to mining regions, however, is limited. This paper examines why this is the case and how to confront it.
The paper focuses on identifying and describing features of large-scale mines and mine regions that are chal
lenging to analyse such as: magnitude of capital involved, time-scale and remoteness of projects, inherent en
vironmental risks, and strong negative perceptions about minings impacts on water. These characteristics may
limit the applicability of established hydro-economic concepts and methods, thus risk-based metrics are dis
cussed as complementary tools. We also contend that further research and development in water-related eco
system services should be a priority, in order to better quantify trade-offs between the economic benefits of
water use by mining and competing users, including environmental flows. Case studies of mining regions in
Chile, Madagascar and Sweden are summarised to illustrate some of the issues raised. While data limitations are
an obstacle, new and extended case studies are required to explore how the challenges may be addressed.
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مقاله انگلیسی |
28 |
Sustainability impacts of tidal river management: Towards a conceptual framework
اثرات توسعه پایدار از مدیریت رودخانه جزر و مدی: به سوی یک چارچوب مفهومی-2018 The Southwest Coastal people of Bangladesh have introduced Tidal River Management (TRM) as an en
vironmentally acceptable water resource management practice based on their indigenous knowledge of water
logging of low lying coastal land. TRM helps to address problems resulting from different anthropogenic and
structural development activities, and it has been successful in helping coastal communities to adapt to climate
change and rising sea level vulnerability by forming new land in Tidal Basins. Hence, it is essential to measure
sustainability impacts of TRM from the environmental, socio-economic and institutional perspectives. Therefore,
firstly, the study identifies sustainability indicators of TRM considering ecosystem services and secondly, de
velops an inclusive conceptual framework to understand the important impacts of each indicator at various
spatial and temporal scales. The conceptual framework is followed by the construction of a Sustainability Index
of Tidal River Management (SITRM). It has advantages over the Ramsar Convention framework (2007) and the
World Meteorological Organization (WMO) framework (2012) to measure water sustainability as it includes a
sustainable model to project future vulnerability of the community, river and Tidal Basin, emphasizing on cli
mate change issues. It also involves trade-offs analysis, livelihood analysis and SWOT (Strengths, Weaknesses,
Opportunities and Threats) analysis for a complete impact assessment to enable decision-makers to focus on
those services most likely to be of risks and weaknesses or opportunities and strengths for the sustainability of
TRM. Moreover, the framework is a useful guide for policymakers in identifying the sustainability impacts of
TRM so that they can choose best coping strategies for coastal people to effectively deal with adverse effects of
water-logging and undesired climatic events as well as environmental and socio-economic changes in coastal
areas.
Keywords: Sustainability indicators ، Sustainability index ، Water management ، Climate change ، Sedimentation ، Water-logging |
مقاله انگلیسی |
29 |
برنامهریزی برای بداههنوازی؟ نقش استدلال در فرایند استراتژی: شواهدی از مالزی
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 22 - تعداد صفحات فایل doc فارسی: 34 در متون و مقالات فرایند استراتژی، برنامهریزی و بداههنوازی به عنوان جهت گیریهای متناوب تصمیمگیری شناخته میشوند، اینها توسط دو بستر شناختی موازی اجرا میشوند: منطق و شهود، اما آیا میتوان آنها را منطقی یا شهودی در فرایند استراتژی، هماهنگ نمود؟ مدیران استراتژی ممکن است مجبور به انتخاب از میان طرح یا بداههسازی نشوند، بلکه نیاز است تمرکز پژوهشها را از اینگونه مصالحهها به تفکر تناقضی تغییر دهند. ما براساس دادههای نظرسنجی برگرفته از شرکتهای تحقیقاتی ژرفانگر مالزیایی، نحوهی توسعهی راهبرد از طریق استدلال استراتژی مدیران تحت شرایط احتمالی بیرونی (تلاطم بازار) و داخلی (مرکزگرایی، سطح مدیریت) را بررسی نمودیم. در مقابل فرضیات رایج در متون و مقالات مدیریت، دریافتیم که هم استدلال منطقی و هم شهودی میتواند محرکی برای برنامهریزی و بداههنوازی برای شرکتها در اقتصادهای نوظهور باشد، این یک سری اثرات تعدیل مثبت اضافی در سطح مدیریت و مرکزگرایی را نیز به همراه دارد. شرکتهایی که همزمان به سطوح بالاتر برنامهریزی و بداههنوازی دست مییابند، عقلانیت بسیار بالاتری نسبت به گروه دارای سطح بالای برنامهریزی یا گروه دارای سطح بالای بداههنوازی دارند. این یافتهها، پژوهشهای فرآیند استراتژی را بسط میدهند، اینها نشان میدهند شرکتها در اقتصادهای نوظهور به چه نحو از نظریهی حاصل از نظامهای اقتصادی پیشرفته فاصله میگیرند.
کلیدواژه: نظام اقتصادی نوظهور | برنامهریزی | بداههنوازی | استدلال | مالزی | فرآیند استراتژی |
مقاله ترجمه شده |
30 |
Extending the coverage of the internet of things with low-cost nanosatellite networks
گسترش پوشش اینترنت اشیاء با شبکه های کم هزینه نانوساختاری-2017 Recent technology advances have made CubeSats not only an affordable means of access to space, but also
promising platforms to develop a new variety of space applications. In this paper, we explore the idea of using
nanosatellites as access points to provide extended coverage to the Internet of Things (IoT) and Machine-to
Machine (M2M) communications. This study is mainly motivated by two facts: on the one hand, it is already
obvious that the number of machine-type devices deployed globally will experiment an exponential growth over
the forthcoming years. This trend is pushed by the available terrestrial cellular infrastructure, which allows
adding support for M2M connectivity at marginal costs. On the other hand, the same growth is not observed in
remote areas that must rely on space-based connectivity. In such environments, the demand for M2M commu
nications is potentially large, yet it is challenged by the lack of cost-effective service providers. The traffic
characteristics of typical M2M applications translate into the requirement for an extremely low cost per trans
mitted message. Under these strong economical constraints, we expect that nanosatellites in the low Earth orbit
will play a fundamental role in overcoming what we may call the IoT digital divide. The objective of this paper is
therefore to provide a general analysis of a nanosatellite-based, global IoT/M2M network. We put emphasis in the
engineering challenges faced in designing the Earth-to-Space communication link, where the adoption of an
efficient multiple-access scheme is paramount for ensuring connectivity to a large number of terminal nodes. In
particular, the trade-offs energy efficiency–access delay and energy efficiency–throughput are discussed, and a
novel access approach suitable for delay-tolerant applications is proposed. Thus, by keeping a system-level
standpoint, we identify key issues and discuss perspectives towards energy efficient and cost-effective solutions.
Keywords: Cubesat applications | Internet of things | M2M | Energy-efficiency | Random access | Multiple-access |
مقاله انگلیسی |