Proceedings of the Bulgarian Academy of Sciences最新文献_第5页

Design and Implementation of Multilevel Inverter Topology with Reduced Switching Components 减少开关元件的多电平逆变器拓扑结构的设计与实现

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.11

Jayakumar Velayutham, K. Ramasamy

{"title":"Design and Implementation of Multilevel Inverter Topology with Reduced Switching Components","authors":"Jayakumar Velayutham, K. Ramasamy","doi":"10.7546/crabs.2024.01.11","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.11","url":null,"abstract":"Multilevel inverters play a vital role in renewable energy applications. In this paper we designed a new MLI topology for various renewable energy sources application with fewer switches using the multiple pulse width modulation technique. H-Bridge MLI topology is designed and implemented in an asymmetrical configuration. The equal amplitude of DC sources is symmetric, and unequal amplitude DC sources are used asymmetrically. On operating the MLI in an asymmetric design with four voltage sources, eight switches and 15-level output is produced, while in symmetric mode 9-level output is produced. The low-frequency modulation scheme is applied with a designed switching pattern where the switching period is pre-determined. The proposed topology is designed with reduced switches, minimal total harmonic distortion (THD) and the results are compared with conventional multilevel inverter topologies. The proposed MLI topology performance is validated and verified with number of switches and voltage levels and mainly LSR & CLF. Fifteen-level MLI operation is also simulated using MATLAB platform for experimental validation. The results produced by proposed topology are found to be encouraging and superior than any other conventional topology.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"45 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140487696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Breast Cancer Stem Cells – Diagnostic and Prognostic Significance 乳腺癌干细胞--诊断和预后意义

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.05

Zdravka Petrova, R. Spasov, Radostina Alexandrova

引用次数: 0

Structural-genetic Characteristics of Landscapes of the Southeastern Slope of the Great Caucasus and Study of Their Modern State 大高加索东南坡地景观的结构-遗传特征及其现代状态研究

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.08

A. Hajiyeva, Firuza Jafarova, Gulnar Hajiyeva

{"title":"Structural-genetic Characteristics of Landscapes of the Southeastern Slope of the Great Caucasus and Study of Their Modern State","authors":"A. Hajiyeva, Firuza Jafarova, Gulnar Hajiyeva","doi":"10.7546/crabs.2024.01.08","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.08","url":null,"abstract":"The structural-genetic characteristics of landscapes have an important role in the formation of landscapes, the spread of agrocomplexes, the assimilation of landscapes and other directions. At present, these studies are conducted using modern methods, based on the processing of satellite images with the help of Geographical Information Systems. We also applied this practice for the first time in our country. In this regard, our research is relevant. Our goal is to determine the future development trends of landscape use by studying the structural-genetic characteristics of landscapes with modern methods. As a result of the analysis of the structural-genetic characteristics and morphometric elements of the modern natural landscapes in the studied area, three landscape sectors, which are sharply different from each other due to height differentiation and structure, were separated: 1. Atachay-Tughchay; 2. Pirsaatchay-Sumgayitchay; 3. Girdimanchay-Agsuchay. \u0000It was determined that the spectra of natural terrain complexes, hypsometric levels, and tendencies of anthropogenic transformations in the high landscape sectors are different, and based on these calculations, map schemes and tables were drawn up. When examining the structural-genetic characteristics of the studied area, the strength of anthropogenic influences throughout history is clearly visible, considering that there are quite ancient settlements in the research area.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"45 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140488330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Lateralized Active Avoidance Learning and Memory to Ang II and Losartan Microinjected into Amygdala in Rats Depression Model 抑郁模型大鼠对杏仁核微注射 Ang II 和洛沙坦的侧向主动回避学习和记忆

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.06

R. Tashev, Hristina Nocheva, Margarita Velikova

{"title":"Lateralized Active Avoidance Learning and Memory to Ang II and Losartan Microinjected into Amygdala in Rats Depression Model","authors":"R. Tashev, Hristina Nocheva, Margarita Velikova","doi":"10.7546/crabs.2024.01.06","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.06","url":null,"abstract":"Depression is a widespread socially significant disease. Studies aiming to reveal the pathogenesis of depression have lasted for decades, but the specific mechanisms remain unclear. Olfactory bulbectomy (OBX) in rats provides a well-validated animal model of depression and Alzheimer's disease. The aim is to evaluate the involvement of Ang II and AT1 receptors in learning and memory after unilateral infusion of Ang II and losartan (specific AT1 antagonist) into CeA (central nucleus of the amygdala) in rats with a model of depression (bilateral olfactory bulbectomy, OBX). The effects of Ang II and losartan infused into CeA on the avoidance performance in OBX rats using the active avoidance (shuttle box) test were investigated. A stereotaxic technique was used for bilateral implantation of guide cannulae into CeA. Fourteen days after OBX, Ang II, or losartan were microinjected unilaterally into CeA of rats with depressive-like behaviour. For the first time it was found that Ang II infused into the left CeA impaired learning and memory, while losartan infused into the left CeA significantly improved these processes and prevented the memory deficits induced by the bulbectomy. The data suggest an involvement of amygdala Ang II and AT1 receptors in learning and memory of rats and a differential distribution of the AT1 receptors in the left and right central nucleus of the amygdala in rats with a model of depression.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polyamine Alterations of Triticale in Response to Herbicide, Drought and Waterlogging Treatments 多胺在除草剂、干旱和水涝处理下的变化

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.18

Z. Katerova, Asya Petrova, I. Sergiev, D. Todorova

引用次数: 0

Immunohistochemical Study of Female Breast Cancer in Varna, Bulgaria 保加利亚瓦尔纳女性乳腺癌免疫组化研究

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.07

Galina Yaneva, Ivan Maslarski

引用次数: 1

New Approach to Underwater Image Enhancement Using Modified Residual Blocks in Generator Architecture for Improved Cycle Generative Adversarial Networks 水下图像增强的新方法：利用生成器架构中的修正残差块改进循环生成对抗网络

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.09

Karthik Selvaraju, Samson Rajamani

{"title":"New Approach to Underwater Image Enhancement Using Modified Residual Blocks in Generator Architecture for Improved Cycle Generative Adversarial Networks","authors":"Karthik Selvaraju, Samson Rajamani","doi":"10.7546/crabs.2024.01.09","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.09","url":null,"abstract":"Images captured underwater frequently have a low resolution as a result of a number of issues including light attenuation, backscattering, and colour distortion. The restoration of underwater images, which serves as an essential building block for the field of underwater vision research, remains a difficult endeavor. The process of removing the haziness and the colour distortion caused by the underwater environs is the main focus of the work that goes into the restoration of underwater images. Within the confines of this research, we present an enhanced approach for the enhancement of underwater images called Improved Cycle GAN (Generative Adversarial Network). The suggested approach makes use of a dual architecture that is composed of a generator network and a discriminator network in order to learn the mapping between low-quality underwater photographs and high-quality images. This dual architecture is comprised of a generator network and a discriminator network. The generator network is trained to transform the input image into an enhanced image, while the discriminator network evaluates the realism of the generated images. The suggested method outperforms state-of-the-art visual quality methods on a real-world UFO underwater image dataset. The proposed method is used to recover the original image. In order to measure quantity, the underwater image quality measure attributes called underwater image colourfulness measure (UICM), underwater image sharpness measure (UISM), and underwater image contrast measure (UIConM) are assessed. The proposed method could be employed in various underwater imaging processing applications, such as underwater surveillance, marine biology research, and underwater exploration, where high-quality images are crucial for effective analysis and decision-making.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"39 2-3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140489714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mersenne Numbers in Generalized Lucas Sequences 广义卢卡斯序列中的梅森数

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.01

Alaa Altassan, Murat Alan

引用次数: 0

Chemerin in Obese Patients with Nonalcoholic Fatty Liver Disease with or without Prediabetes Chemerin 在伴有或不伴有糖尿病前期的非酒精性脂肪肝肥胖患者中的应用

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.15

V. Karamfilova, Iveta Nedeva, Y. Assyov, A. Gateva, T. Velikova, N. Cherkezov, L. Mateva, Z. Kamenov

{"title":"Chemerin in Obese Patients with Nonalcoholic Fatty Liver Disease with or without Prediabetes","authors":"V. Karamfilova, Iveta Nedeva, Y. Assyov, A. Gateva, T. Velikova, N. Cherkezov, L. Mateva, Z. Kamenov","doi":"10.7546/crabs.2024.01.15","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.15","url":null,"abstract":"Chemerin is one of the recently discovered adipokines closely related with white adipose tissue and insulin resistance (IR) in obesity, type 2 diabetes mellitus (T2DM), and nonalcoholic fatty liver disease (NAFLD), but some of these data remain controversial. \u0000This study evaluated the relationship between serum chemerin levels, prediabetes and other biochemical and clinical parameters in obese patients with NAFLD. \u0000A total of 79 obese NAFLD patients without ($n=41$) and with prediabetes ($$n=38$$) were included. Serum chemerin was measured using ELISA method. \u0000Chemerin correlated with body mass index (BMI) ($$r=0.320$$, $$p<0.01$$), hip circumference ($$r=0.296$$, $$p<0.05$$) and visceral adiposity index (VAI) ($$r=0.297$$, $$p<0.05$$). Chemerin strongly correlated with hepatic steatosis index (HSI) ($$r=0.550$$, $$p<0.01$$). \u0000Chemerin is adipokine, which has a significant, but yet not unequivocal role in the metabolic process related with obesity, insulin resistance and NAFLD. In this study we were not able to find an association of serum chemerin levels and prediabetes. There were correlations with BMI, hip circumference, Visceral adiposity index and Hepatic steatosis index.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"13 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140489547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Automated Statistical Analysis for Improving HEIs Training Performance 提高高等院校培训绩效的自动化统计分析

Proceedings of the Bulgarian Academy of Sciences Pub Date : 2024-01-29 DOI: 10.7546/crabs.2024.01.10

Silvia Gaftandzhieva, R. Doneva, Milen Bliznakov

{"title":"Automated Statistical Analysis for Improving HEIs Training Performance","authors":"Silvia Gaftandzhieva, R. Doneva, Milen Bliznakov","doi":"10.7546/crabs.2024.01.10","DOIUrl":"https://doi.org/10.7546/crabs.2024.01.10","url":null,"abstract":"Among the most vital key performance indicators for the quality of educational services offered by higher education institutions (HEIs) are students' retention and success rate. The number of trained students is also decisive for financing HEIs. Therefore, HEIs leaders need continuous access to data on current students in aggregated form to help them to formulate concrete and consistent, data-driven decisions to improve the quality of educational services, to attract and retain more students, and monitor the number of students. This paper offers a software tool developed for decision-making bodies in Bulgarian HEIs (deans' and rectors' management). The tool retrieves and analyses data from university information systems on students and generates aggregated reports that allow governing bodies to track the number of students at different levels (study programme, faculty, professional field) and to monitor indicators related to the accomplishment of the institutional training capacity determined by the state for admission (maximum number of students). These reports can help HEIs leaders to make timely, data-driven decisions for increasing student retention rate, determining how many admission places it can announce, and the need to change the capacity within the following accreditation procedure. Results of tool experimentation are discussed.","PeriodicalId":104760,"journal":{"name":"Proceedings of the Bulgarian Academy of Sciences","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140489361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0