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نتیجه جستجو - Contrast

تعداد مقالات یافته شده: 438
ردیف عنوان نوع
41 MRI-based traditional radiomics and computer-vision nomogram for predicting lymphovascular space invasion in endometrial carcinoma
رادیومیک سنتی مبتنی بر MRI و نام نگاری رایانه ای برای پیش بینی تهاجم فضایی لنفاوی در سرطان آندومتر-2021
Purpose: To determine the capabilities of MRI-based traditional radiomics and computer-vision (CV) nomogram for predicting lymphovascular space invasion (LVSI) in patients with endometrial carcinoma (EC).
Materials and methods: A total of 184 women (mean age, 52.9 ± 9.0 [SD] years; range, 28–82 years) with EC were retrospectively included. Traditional radiomics features and CV features were extracted from preoperative T2-weighted and dynamic contrast-enhanced MR images. Two models (Model 1, the radiomics model; Model 2, adding CV radiomics signature into the Model 1) were built. The performance of the models was evaluated by the area under the curve (AUC) of the receiver operator characteristic (ROC) in the training and test cohorts. A nomogram based on clinicopathological metrics and radiomics signatures was developed. The predictive performance of the nomogram was assessed by AUC of the ROC in the training and test cohorts.
Results: For predicting LVSI, the AUC values of Model 1 in the training and test cohorts were 0.79 (95% confidence interval [CI]: 0.702–0.889; accuracy: 65.9%; sensitivity: 88.8%; specificity: 57.8%) and 0.75 (95% CI: 0.585–0.914; accuracy: 69.5%; sensitivity: 85.7%; specificity: 62.5%), respectively. The AUC values of Model 2 in the training and test cohorts were 0.93 (95% CI: 0.875–0.991; accuracy: 94.9%; sensitivity: 91.6%; specificity: 96.0%) and 0.81 (95% CI: 0.666–0.962; accuracy: 71.7%; sensitivity: 92.8%; specificity: 62.5%), respectively. The discriminative ability of Model 2 was significantly improved compared to Model 1 (Net Reclassification Improvement [NRI] = 0.21; P = 0.04). Based on histologic grade, FIGO stage, Radscore and CV-score, AUC values of the nomogram to predict LVSI in the training and test cohorts were 0.98 (95% CI: 0.955–1; accuracy: 91.6%; sensitivity: 91.6%; specificity: 96.0%) and 0.92 (95% CI: 0.823–1; accuracy: 91.3%; sensitivity: 78.5%; specificity: 96.8%), respectively.
Conclusions: MRI-based traditional radiomics and computer-vision nomogram are useful for preoperative risk stratification in patients with EC and may facilitate better clinical decision-making.
Keywords: Uterus | Endometrial neoplasm | Magnetic resonance imaging | Nomogram | Computer vision
مقاله انگلیسی
42 تمایز خونریزی حاصل از افزایش کنتراست با استفاده از CT طیف سنجی با لایه دوگانه در بیماران سکته حاد
سال انتشار: 2021 - تعداد صفحات فایل pdf انگلیسی: 4 - تعداد صفحات فایل doc فارسی: 8
بیماران سکته حاد به مراکز دارای ترومبکتومی(لخته برداری) (TCC) انتقال می یابند و پس از ورود به TCC ، تحت معاینه CT سر قرار می گیرند تا نمره ASPECTS و خونریزی داخل جمجمه آنها ارزیابی شود. تقویت پارانشیمی در بیمارانی که کنتراست یددار یا iodinated را قبل از انتقال دریافت کرده اند، در شبیه سازی خونریزی در این CT و پس از انتقال کمک می کند. دو مورد از کاربرد تصویربرداری طیفی CT به منظور تمایز بین افزایش کنتراست پارانشیمی و خونریزی در این مطالعه گزارش شده است. روش TCC، تصویربرداری با انرژی دوگانه یا لایه دوگانه (طیفی) را برای این گروه بیمار در نظر می گیرد.
کلمات کلیدی: سکته مغزی | تصویربرداری طیفی CT
مقاله ترجمه شده
43 Informed conservation management of rare tree species needs knowledge of species composition, their genetic characteristics and ecological niche
مدیریت حفاظت از حفاظت از گونه های نادر درختی، نیاز به دانش ترکیب گونه ها، ویژگی های ژنتیکی آنها و طاقچه های زیست محیطی -2021
Woodland nature reserves must be scientifically assessed so that subsequent management leads to optimal conservation of biodiversity. This entails knowledge of the species composition, the genetics of the local pop- ulations and their ecology. Here we assess Tilia species in the Bavarian Forest National Park (BFNP), a large mixed coniferous and deciduous forest in South-Eastern Germany. Tilia occurs here at low density, as in many other mixed forests in Central and Northern Europe. Therefore, results are not only relevant to BFNP but also to other areas. Exhaustive sampling resulted in the collection of 113 mature trees that were genotyped using 20 microsatellite markers, derived from both T. cordata and T. platyphyllos. For the first time, size and aspect of trees, and their community association were contrasted between the species. Genotyping confirmed that T. platyphyllos, T. cordata and their hybrid (T. x europaea) were present in the BFNP and both species deserve conservation. T. platyphyllos has a higher genetic diversity for both sets of markers than T. cordata, confirming earlier work. Both species showed genetic diversity comparable to other populations in Central Europe, which is likely to be sufficient for the maintenance of the species in the short term. However, increasing the number of trees, ensuring local sources are used, and gene flow from surrounding forests over the next decennia may be crucial for long- term survival. Further, within the T. platyphyllos group there was a set of 11 trees that were distinct from the others: they had a lower genetic diversity and were shorter. We hypothesise that these were planted and should not be used for propagation and augmentation. Most saplings analysed appeared to derive from asexual propagation (36 out of 41), although a few (five out of 41) were novel genotypes. This means that, currently, there is some, but rather limited, regeneration. T. cordata was found at a lower altitude and less steep terrain than T. platyphyllos and the hybrid. The hybrid was taller than the two species, while the diameter at breast height was smallest in T. cordata. T. cordata shows a preference for mixed and coniferous forests, while T. platyphyllos occurs mostly in deciduous forests. Our results indicate that biodiversity at the species and genetic level as well as species’ ecology have to be considered in order to guide informed conservation management. These results form the basis to recommend conservation management improving the long-term viability of Tilia in the BFNP and other mixed forests.
keywords: جنگلداری | تیلیا | تنوع ژنتیکی | ترجیح زیستگاه | مناطق حفاظت شده | هیبریداسیون | جنگلکاری | Forestry | Tilia | Genetic diversity | Habitat preference | Protected areas | Hybridisation | Silviculture
مقاله انگلیسی
44 The effects of inter- and intraorganizational factors on the adoption of electronic booking systems in the maritime supply chain
اثرات عوامل بین و درون سازمانی بر پذیرش سیستم های رزرو الکترونیکی در زنجیره تأمین دریایی-2021
Digitalization is currently reshaping business models and providing more opportunities for cross-border supply chains. Maritime transportation occupies a crucial position in the global supply chain and information systems are playing an increasingly important role in the industry. In contrast with information systems used in other industries, interorganizational information systems in the maritime industry may involve a greater number of organizational users, including manufacturers, customers, shipping lines and customs and port authorities from different countries. Therefore, the adoption of container e-booking systems in the maritime supply chain is complex and with limited scrutiny in academia. This study explored the use of e-booking systems in the maritime supply chain and, in particular, the factors influencing the adoption of such systems at the organizational level. The study aimed to close the gap between the general understanding of the adoption of information systems and the adoption of e-booking systems in a specific context, namely the maritime supply chain. We conducted an exploratory multi-case study of eight firms across multiple tiers of the maritime supply chain. We employed a qualitative approach to investigate this issue at the maritime supply chain level, rather than the firm level. The study focused on inter- and intraorganizational factors. The results suggest that adoption is influenced by several factors, including pressure from trade partners, pressure from leading organizations, as well as organizational compatibility, and so forth. Furthermore, the identified factors have different levels of impact across organizational tiers in the shipping chain. This study offers insights that are relevant to both researchers and practitioners in the maritime transportation industry and may help to accelerate the digitalization of the industry.
Keywords: E-booking systems | Information systems | Adoption | Maritime supply chain | Inter and intra-organizational factors
مقاله انگلیسی
45 Dynamic capabilities in sustainable supply chain management: An inter-temporal comparison of the food and automotive industries
قابلیت های پویا در مدیریت پایدار زنجیره تأمین: مقایسه بین زمانی صنایع غذایی و خودرو-2021
This paper seeks to enrich the theoretical debate on dynamic capabilities (DCs) in sustainable supply chain management (SSCM). By extending Beske et al.’s (2014) study, a systematic literature review was conducted, and articles matching our inclusion criteria were analyzed from 2002 to 2018. Yet, two major additions are made. For the first time, two distinctive sectors, i.e., the food and automotive industry, are compared. Furthermore, a temporal perspective is provided by comparing two time periods (2002–2013 and 2014–2018) based on content as well as quantitative contingency analyses.The results for the food sector indicate a shift from “standards and certifications,” a central construct within the 2002–2013 sample, to proactive strategies aiming for the integration of stakeholders in the 2014–2018 sample. Similarly, the findings of the automotive industry indicate a shift from monitoring to joint development and knowledge management. Based on our comparison, the SSCM debate in the food industry appears more diverse in terms of practices and capabilities employed. In contrast, the analysis for the automotive industry indicates a focus on SCM elements instead of a comprehensive SSCM view. To the best of our knowledge, this is the first attempt to apply an intra- and inter-sectoral analysis combined with a temporal analysis within the SSCM domain. This provides evidence that the methodological approach taken allows distinguishing among both time periods and industries.
Keywords: Sustainable supply chain management | Dynamic capabilities | Automotive industry | Food industry
مقاله انگلیسی
46 Vision based prediction of surface roughness for end milling
پیش بینی مبتنی بر دید از زبری سطح برای فرز نهایی-2021
Measurement of surface roughness helps to assess the machined component’s functionality. In the past three decades, several scientists have contributed to the computation of surface roughness. This research article deals with two distinct methods for prediction of surface roughness employing the surface pro- filometer and machine vision for AISI 1040 steel specimens prepared by varying cutting parameters of end milling viz. feed rates, speed and cutting depth. Using a surface profilometer, the surface roughness parameters are evaluated. At the other hand, the texture features were extracted using a Gray Level Co- occurrence Matrix Algorithm (GLCM) and a computer vision system. Correlations are formed among characteristics of machined surface and the texture feature such as contrast, entropy, energy, and homogeneity. The comparable findings revealed a maximum relative error of —8% using contrast and energy, — 11% using entropy and —10% using homogeneity.© 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials, Processing & Characterization.
Keywords: Surface roughness parameter | Gray Level Co-occurrence Matrix (GLCM) | Texture feature | Machine vision system | Linear regression
مقاله انگلیسی
47 Color Image Enhancement based on Gamma Encoding and Histogram Equalization
بهبود تصویر رنگی بر اساس رمزگذاری گاما و یکسان سازی هیستوگرام-2021
Image Enhancement is used as a preprocessing step in many computer vision applications. It provides enhanced input for other computerized image processing methods. Many preprocessing techniques can be applied to images depending on the application domain. In this paper we are proposing an image enhancement technique for color images that can be used as preprocessing step in many computer vision applications. It can also be used as a data augmentation technique in object detection. Luminance component of images is sometimes not captured by cameras and displayed by monitors properly. To remove this drawback of devices we have used gamma encoding. Four different values of gamma are evaluated depending on the quality of images. Image is then converted into YUV Color space. Y component represents the luminance. U and V components represent color. After that Contrast Limited Adaptive Histogram Equalization is applied to the Y component to improve the contrast of the image. The results are compared with the state-of-the-art methods on the basis of Peak Signal to noise Ratio (PSNR) and Mean Square Error (MSE). Quantitative results show that proposed algorithm results in improved value of PSNR and decreased value of MSE as compared to existing methods. Qualitative comparison is also done and results show improvement over the existing techniques.© 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials, Manufacturing and Mechanical Engineering for Sustainable Developments-2020.
Keywords: Histogram | Intensity | Luminance | Contrast stretching
مقاله انگلیسی
48 The application of blockchain-based crypto assets for integrating the physical and financial supply chains in the construction & engineering industry
کاربرد دارایی های رمزنگاری مبتنی بر بلاکچین برای ادغام زنجیره های تأمین فیزیکی و مالی در صنعت ساخت و مهندسی-2021
Supply chain integration remains an elusive goal for the construction and engineering industry. The high degree of fragmentation and the reliance on financial institutions has pushed the physical and financial supply chains apart. The paper demonstrates how blockchain-based crypto assets address this limitation when used for conditioning payments on the flow of products. The integration of flows is contrasted in today’s supply chains and those using crypto assets for their payment settlement. The thesis is validated in two construction projects where a smart contract administered payments in crypto currencies and crypto tokens. The findings reveal that crypto assets can enhance both the granularity and the atomicity of the integration between the cash and product flows; the on- and off-chain realities can be directly linked in crypto asset-enabled supply chains. The paper concludes with a discussion of risks such as regulatory landscapes, security, and price volatility and offers potential solutions.
مقاله انگلیسی
49 Management accountants and strategic management accounting: The role of organizational culture and information systems
حسابداران مدیریت و مدیریت استراتژیک مدیریت: نقش فرهنگ سازمانی و سیستم های اطلاعاتی-2021
This study aims to contribute to the scant contingency theory literature on the determinants of strategic man- agement accounting (SMA) practices and the role management accountants play. We develop and test a more complex theoretical model than in prior studies, to simultaneously examine the role of three variables: man- agement accountant networking, information systems (IS) quality and organizational culture. These have not been examined in a single model before in the SMA literature. Using data from 149 UK manufacturing business units and the partial least square structural equation modeling, our findings document a positive relationship between management accountant networking and the implementation of SMA practices. However, this rela- tionship is positively moderated by IS quality, which further enables management accountants to implement SMA practices. Unlike IS quality, we do not find empirical support for similar moderating effects by the outcome- oriented culture and innovation-oriented culture. Instead, the innovation-oriented culture has a significant in- direct positive effect on SMA implementation through management accountant networking but not a direct one. In contrast, we find a direct positive impact of outcome-oriented culture on SMA implementation but not an indirect one through management accountant networking. These results suggest that in outcome-driven business units, the implementation of SMA practices may not be limited to the accounting function. Managers in other functions may be motivated to implement SMA practices even when management accountants are not part of the process.
keywords: حسابداری مدیریت استراتژیک | شبکه حسابدار مدیریت | فرهنگ سازمانی | کیفیت سیستم اطلاعاتی | Strategic management accounting | Management accountant networking | Organizational culture | Information system quality
مقاله انگلیسی
50 Multi-outsourcing supply chain coordination under yield and demand uncertainties
هماهنگی بین زنجیره تامین چند برون سپاری تحت عدم قطعیت عملکرد و تقاضا-2021
As a popular production mode, outsourcing enables the cost saving for original equipment manufacturer (OEM) and the acquisition of advanced technology for contract manufacturer (CM). We consider a multi-outsourcing supply chain within the voluntary compliance regime. The game between one OEM facing uncertain demand and arbitrary CMs owning uncertain yields is modeled to study the interactions regarding lot-sizing decisions. A general method is developed to prove the concavity of profit functions, which is formidable to accomplish based on Hessian Matrix. The optimal ordering and production strategies are subsequently characterized. A revenue sharing with surplus purchase contract with great flexibility in parameter selection is proposed to coordinate the supply chain. We find that there exist threshold outsourcing prices beyond which the CMs are motivated to overproduce, otherwise they tend to produce in consistent with the orders. In a competitive market, price war is not a wise strategy for CM due to profit sacrifice. By contrast, if the selling price charged by the OEM is high, a smart CM can appropriately raise its outsourcing price because the order quantity difference among CMs is relatively small. Although supply stability improvement and outsourcing price reduction are both welcomed by the OEM, the latter is more important for it to consider in allocating orders.
Keywords: Multiple sourcing | Supply chain management | Random yield | Newsvendor | Game theory
مقاله انگلیسی
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