مطالب مرتبط با کلیدواژه

Segmentation


۱.

Investigation of Customer Priorities for Machine Made Carpet Through Conjoint and Cluster Analysis (Case Study in Yazd, Iran)(مقاله علمی وزارت علوم)

کلیدواژه‌ها: Conjoint analysis Customer's preferences Segmentation Machine made carpet Yazd

حوزه‌های تخصصی:
تعداد بازدید : ۸۸۷ تعداد دانلود : ۴۵۱
The machine made carpet industry is one of the main and most famous industries in Iran and especially in the city of Yazd. However there is little information about customer preferences for different attributes of this product. In this article we tried to estimate the relative importance of the main attributes affecting customer desire for purchasing machine made carpet and the utility values for the different levels of each one by means of conjoint analysis. In addition to this, we created customer segments with similar preference structures using cluster analysis. Six attributes have been considered in this paper: design, color, number of colors, density, primary material and brand. Twenty seven profiles by combining different levels of these attributes using fractional factorial design approach have been created. These profiles were evaluated by 380 customers in the city of Yazd. Results have shown that design of carpet is the most important attribute for the choice of carpet. Color, primary material, brand, density and number of colors are the next priorities for customers respectively. Also cluster analysis identified five clusters of customers with similar preferences.
۲.

Comparative Analysis between Active Contour and Otsu Thresholding Segmentation Algorithms in Segmenting Brain Tumor Magnetic Resonance Imaging(مقاله علمی وزارت علوم)

کلیدواژه‌ها: Brain tumor Magnetic Resonance Imaging (MRI) Segmentation Active contour Otsu threshold

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تعداد بازدید : ۳۴۷ تعداد دانلود : ۱۳۹
The accuracy of brain tumor detection and segmentation are greatly affected by tumors’ location, shape, and image properties. In some situations, brain tumor detection and segmentation processes are greatly complicated and far from being completely resolved. The accuracy of the segmentation process significantly influences the diagnosis process, such as abnormal tissue detection, disease classification, and assessment. However, medical images, in particular, the Magnetic Resonance Imaging (MRI), often include undesirable artefacts such as noise, density inhomogeneity, and partial volume effects. Although many segmentation methods have been proposed, the accuracy of the segmentation results can be further improved. Subsequently, this study attempts to provide very important properties about the size, initial location and shape of tumors known as Region of Interest (RoI) to kick-start the segmentation process. The MRI consists of a sequence of images (MRI slices) of a particular person and not one image. Our method chooses the best image among them based on the tumor size, initial location and shape to avoid the partial volume effects. The selected algorithms to test our method are Active Contour and Otsu Thresholding algorithms. Several experiments are conducted in this research using the BRATS standard dataset that consist of 100 samples. These experiments comprised of MRI slices of 65 patients. The proposed method is evaluated by the similarity coefficient as a standard measure using Dice, Jaccard, and BF scores. The results revealed that the Active Contour algorithm has higher segmentation accuracy when tested across the three different similarity coefficients. Moreover, the achieved results of the two algorithms verify the ability of the proposed method to choose the best RoIs of the MRI samples.
۳.

Automatic Chest CT Image Findings of Novel Coronavirus Pneumonia (COVID-19) Using U-Net Based Convolutional Neural Network(مقاله علمی وزارت علوم)

کلیدواژه‌ها: COVID-19 CT imaging findings Segmentation deep learning Ground-glass opacities U-Net

حوزه‌های تخصصی:
تعداد بازدید : ۲۲۳ تعداد دانلود : ۱۷۲
The continuing outbreak of COVID-19 pneumonia is globally concerning. Timely detection of infection ensures prompt quarantine of patient which is crucial for preventing the rapid spread of this contagious disease and also supports the patient with necessary medication. Due to the high infection rate of COVID-19, our health management system needs an automatic diagnosis tool that equips the health workers to pay immediate attention to the needy person. Chest CT is an essential imaging technique for diagnosis and staging of 2019 novel coronavirus disease (COVID-19). The identification of COVID-19 CT findings assists health workers on further clinical evaluation, especially when the findings on CT scans are trivial, the person may be recommended for Reverse-transcription polymerase chain reaction (RT-PCR) tests. Literature reported that the ground-glass opacity (GGO) with or without consolidation are dominant CT findings in COVID-19 patients. In this paper, the U-Net based segmentation approach is proposed to automatically segment and analyze the GGO and consolidation findings in the chest CT scan. The performance of this system is evaluated by comparing the auto-segmented infection regions with the manually-outlines ones on 100 axial chests CT scans of around 40 COVID-19 patients from SIRM dataset. The proposed U-Net with pre-process approach yields specificity of 0.91 ± 0.09 and sensitivity of 0.87 ± 0.07 on segmenting GGO region and specificity of 0.81 ± 0.13 and sensitivity of 0.44 ± 0.17 on segmenting consolidation region. Also the experimental results confirmed that the automatic detection method identifies the CT finding with a precise opacification percentage from the chest CT image.
۴.

Optimal Promotional Effort Policy for Innovation Diffusion Model in a Fuzzy Environment(مقاله علمی وزارت علوم)

کلیدواژه‌ها: fuzzy parameter Segmentation Optimal control problem

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تعداد بازدید : ۱۶۳ تعداد دانلود : ۱۲۳
In today’s era when a substitute for almost every product is readily available, acceptance and adoption of a new product in a market requires substantial amount of promotion. Here we formulate and analyze policies for promoting sales of a product in a market through optimal control theory problems. The market is partitioned into various segments depending upon multifarious demands of customers and promotion of the product is done segment-wise. The aim is to maximize the profits keeping in mind the demand requirements and the available budget for promotion. In order to provide a realistic model, the total available budget is taken to be imprecise. The optimal control model with fuzzy parameter is converted into crisp form using necessity and possibility constraints, and thereafter solved by using Pontryagin Maximum principle. To illustrate this technique, a numerical example is also considered by discretizing the model. The analysis also gives a deep insight of how the promotional effort should be planned by the decision makers keeping in mind the financial constrains without hindering the promotional effort at the end of the planning period. This paper mirrors the real time situation that could be faced by any industry, including that of software development, where budgets may have variable components and promotion of products may vary according to different regions and markets. The experimental data reveals that profitability can still be maximized if real-life constraints are applied in promotional planning by any industry.