در سال‌های أخیر با افزایش پیچیدگی، سطح عدم­اطمینان نیز یافته است؛ ازاین‌رو مدیریت ریسک زنجیره تأمین یکی از موضوع‌هایی است که موردتوجه سازمان‌ها قرار گرفته است. ریسک‌های موجود تأمین، وارده ناحیه تأمین‌کنندگان پژوهش حاضر به‌کارگیری مدلی به‌منظور ارزیابی صنایع غذایی شی­‌فو، به شناسایی محتمل و اتخاذ تصمیماتی راستای می­‌پردازد. مدل به‌کار‌گرفته‌شده، ترکیبی محاسبات کلامی فازی (FLC) محاسبه مقدار عوامل...

Direct-sequence code-division multiple-access (DSCDMA) cellular systems, such as Wideband CDMA (WCDMA), are limited in performance by interference. Several types of Rake Receivers like A-Rake, S-Rake, P-Rake, Adaptive frequency Rake, Time frequency Rake, Conventional MMSE Rake and Adaptive MMSE rake are used for WCDMA. A Beam formerRake receiver can be an effective solution to provide the recei...

The outage probability of a forward link DSCDMA cellular system with fast transmit power control (TPC) based on signal-to-interference ratio (SIR) is investigated. The expression for SIR at the output of RAKE receiver is developed, and the outage probability is evaluated by using Monte Carlo simulation. We consider two kinds of channel models: random delay resolvable path model and tapped delay...

Direct sequence code division multiple access (DSCDMA) using frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion has been attracting much attention as a promising wireless access technique in a frequency-selective fading channel. The conventional FDE requires the insertion of guard interval (GI) to avoid the inter-block interference (IBI). However, GI ins...

A class of unified multicarrier DS-CDMA (MC DS-CDMA) schemes is defined and its performance is considered over multipath Nakagamim fading channels. The spacing between two adjacent subcarriers of the unified MC DS-CDMA scheme is a variable, allowing us to gain insight into the effects of the spacing on the bit error rate (BER) performance of MC DS-CDMA systems. This unified MC DS-CDMA scheme in...

A sub-symbol based multiuser detector for DSCDMA systems was proposed in [1]. This paper addresses the optimization of such detectors to maximize the system capacity. It is shown that the maximum number of simultaneous users supported in a DS-CDMA system using sub-symbol scheme can be increased by the proper selection of certain thresholds delineated in [1], and by imposing moderate synchroniza...

We examine the outage probability of a multi-code DSCDMA system with Minimum Mean Squared Error (MMSE) linear interfenxce suppression. Multi-code DS-CDMA allows different information mtes by varying the number of spreading codes assigned to each user. Power control is used to achieve a set of taryet Signal-to-Inter ference-plus-Noise Ratios (SINRS), and an outage occurs if a user must incnmse t...