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Improved voltage tracking of autonomous microgrid technology using a combined resonant controller with lead-lag compensator adopting negative imaginary theorem

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Protection and Control of Modern Power Systems 2022年第1期7卷 149-164页

作者： md.Yah-Ya ul Haque md.Rashidul islam Tanvir Ahmed md.Rafiqul islam Sheikh Department of Electrical and Electronic Engineering Varendra UniversityRajshahi 6204Bangladesh Department of Electrical and Electronic Engineering Rajshahi University of Engineering&TechnologyRajshahi 6204Bangladesh

Growing application of distributed generation units at remote places has led to the evolution of microgrid(MG)*** an MG system functions independently,i.e.,in autonomous mode,unpredictable loads and uncertainties emerge throughout the *** obtain stable and flexible operation of an autonomous MG,a rigid control mechanism is *** this paper,a robust high-performance controller is introduced to improve the performance of voltage tracking of an MG system and to eliminate stability problems.A combination of a resonant controller and a lead-lag compensator in a positive position feedback path is designed,one which obeys the negative imaginary(NI)theorem,for both single-phase and three-phase autonomous MG *** controller has excellent tracking *** is investigated through considering various uncertainties with different load *** feasibility and effectiveness of the controller are also determined with a comparative analysis with some well-known controllers,such as linear quadratic regulator,model predictive and NI approached resonant *** confirms the superi-ority of the designed controller.

关键词： Negative imaginary theorem Resonant controller Lead-lag compensator Autonomous microgrid Voltage tracking

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迁移学习提高多类图像分类精度的研究

迁移学习提高多类图像分类精度的研究

作者： islam md Mesbah-ul 哈尔滨工业大学

学位级别：硕士

在过去十年中,深度学习以惊人的速度发展。深度神经网络模型用于解决各种实际问题,其中一些问题需要更高的精度和极低的回归系数,包括图像分类、目标检测、自动驾驶汽车的实时分类和监控系统。由于其在各种视觉任务中的应用,图像分类受... 详细信息

在过去十年中,深度学习以惊人的速度发展。深度神经网络模型用于解决各种实际问题,其中一些问题需要更高的精度和极低的回归系数,包括图像分类、目标检测、自动驾驶汽车的实时分类和监控系统。由于其在各种视觉任务中的应用,图像分类受到了相当大的关注,它可助于解决复杂问题。深度神经网络在很大程度上取代了传统的滤波器,可是目前的成像技术无法完全代替人力。因此,考虑如何通过使用迁移学习技术来改进现有的视觉成像技术十分重要。本文的目的是利用转移学习技术提高多类图像分类的精度。深度卷积神经网络结构的发展对于提高图像分类任务的性能至关重要。由于照片的前景复杂,以及不同类别图像之间的相似性,在图像识别方面仍然存在重大障碍。CNN体系结构VGG19、Res Net50、Inception V3和Xception通过具有恒定的基线学习拓扑来提高各自模型的性能,从而得出用于图像分类的结论。多类图像分类工作是使用现有CNN模型和转移学习技术的组合来完成的。主要研究内容如下:根据任务要求,已构建并研究了VGG19、Res Net50、Inception V3和Xception模型的多类图像分类布局方法和体系结构。使用Jupyter notebook中的Keras库,在同一数据集上独立构建所有模型。在后端,使用了Tensor Flow。预处理中的图像增强方法正在得到应用。研究了均值归一化的重要性,并确定了各种数据扩充的方法。通过将输入转换为浮点Num Py数组来预处理输入,该数组生成成批量的浮点张量。研究了模型的过拟合和欠拟合问题,以及是否需要退出正则化。为了提高精度,已配置回调和其他超参数。讨论了降损函数的要求及其对模型性能的影响。分类交叉熵用于评估损失函数。选择Adam优化器来改变神经网络的属性,如权重和学习率,并选择Soft Max分类器来预测图像各自的类别。本文研究了转移学习在多类图像分类中的主要应用方法,并将其应用于我们的多类图像分类挑战。为了减少计算成本和训练时间以及昂贵的数据标记,采用了任务转移学习方法。在迁移学习之后,我们为不同的模型设置不同的可训练参数,以便对模型进行再训练。在编译现有模型并使用迁移学习方法后,我们对CNN模型进行了微调。采用浅层调谐方法,并研究了应微调哪一层。利用分类任务结果进行比较。将用于多类图像分类的深度学习算法的性能与使用相同参数的不同数据集的性能进行比较。与所选预训练模型的精度进行了比较,结果表明,我们的微调模型精度较高;在训练和测试以及模型的整体准确性方面。我们使用同一模型对不同的数据集以及实验中使用的数据集进行了精度比较,发现我们的精度更高。演示深度学习算法的易用性。实验证明,通过确定准确的参数,可以提高多类图像分类的精度;例如学习率、批量大小以及在微调过程中确定准确的可训练参数。通过我们选择的脱落正则化和参数0.5,表明模型不受过拟合问题的影响,从而提高了精度。几位作者使用相同的模型进行了研究并进行了微调;但我们的微调方法和参数与其他方法不同。在迁移学习阶段之后,我们立即开始微调阶段的再训练;这样我们就可以利用预先训练好的模型知识;因此,我们更新了选择性层权重,并减少了计算时间。预先训练的模型使用SGD、RMSprop优化器,但我们使用Adam优化器;在将输入放入分类层之前,我们使用了全局平均池层;因为全局平均池层保留了单个图像特征贴图的深度。在我们的实验中,我们使用了具有选择参数3的早期停止函数。这可以防止模型过度训练。

关键词：多类图像分类深度学习卷积神经网络迁移学习微调

The Influence of Elimination of Roving Frame on Ring Spun Cotton Yarn Characteristics

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World Journal of Engineering and Technology 2023年第1期11卷 10-19页

作者： md. Ikramul islam Sadikur Rahman Mohammad Mohsin ul Hoque Department of Textile Engineering National Institute of Textile Engineering and Research Dhaka Bangladesh

Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminating the roving frame. Total 3 types of yarn with the various linear density of 8 Ne, 10 Ne & 12 Ne were produced using a roving frame and without using a roving frame. In the next step, physical and mechanical properties of those yarns including unevenness, imperfections, hairiness & tenacity were investigated. The result showed that ring spun cotton yarns produced from sliver exhibited inferior physical and mechanical properties compared with samples from the conventional ring spinning system.

关键词： Roving Frame Linear Density Physical and Mechanical Properties Ring Spun Yarn Cotton Yarn

Crop Improvement and Abiotic Stress Tolerance Promoted by Moringa Leaf Extract

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Phyton-International Journal of Experimental Botany 2022年第8期91卷 1557-1583页

作者： md.Abir ul islam Juthy Abedin Nupur Charles T.Hunter Abdullah Al Mamun Sohag Ashaduzzaman Sagar md.Sazzad Hossain Mona F.A.Dawood Arafat Abdel Hamed Abdel Latef Marián Brestič md.Tahjib-UI-Arif Department of Genetics and Plant Breeding Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Agricultural Food and Nutritional ScienceUniversity of AlbertaEdmontonAB T6G 2R3Canada Chemistry Research Unit United States Department of Agriculture-Agricultural Research ServiceGainesville32608USA Department of Biochemistry&Molecular Biology Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Crop Botany Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Agronomy and Haor Agriculture Sylhet Agricultural UniversitySylhet3100Bangladesh Botany and Microbiology Department Faculty of ScienceAssiut UniversityAssiut71516Egypt Botany and Microbiology Department Faculty of ScienceSouth Valley UniversityQena83523Egypt Department of Botany and Plant Physiology Czech University of Life Sciences PraguePrague16500Czech Republic Institute of Plant and Environmental Sciences Faculty of Agrobiology and Food ResourcesSlovak University of AgricultureNitra94976Slovakia

Moringa leaf extract(MLE)has been shown to promote beneficial outcomes in animals and *** is rich in amino acids,antioxidants,phytohormones,minerals,and many other bioactive compounds with nutritional and growth-promoting *** reports indicated that MLE improved abiotic stress tolerance in *** understanding of the mechanisms underlying MLE-mediated abiotic stress tolerance remains *** review summarizes the existing literature on the role of MLE in promoting plant abiotic stress acclimation *** is applied to plants in a variety of ways,including foliar spray,rooting media,and seed *** application of MLE promoted crop plant growth,photosynthesis,and yield under both nonstress and abiotic stress *** treatment reduced the severity of osmotic and oxidative stress in plants by regulating osmolyte accumulation,antioxidant synthesis,and secondary *** also improves mineral homeostasis in the presence of abiotic ***,this review describes the potential mechanisms underpinning MLEmediated stress tolerance.

关键词： Abiotic stress antioxidants biostimulant plant growth moringa extract osmotic stress oxidative stress

Hydrogeochemical evaluation and statistical analysis of groundwater of Sylhet, north-eastern Bangladesh

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Acta Geochimica 2019年第3期38卷 440-455页

作者： Nasir Ahmed md.Bodrud-Doza S.M.Didar-ul islam Manzoor Ahmad Choudhry md.Iftakharul Muhib Anwar Zahid Shahadat Hossain md.Moniruzzaman Nipa Deb md.Abdul Quaiyum Bhuiyan Isotope Hydrology Division Institute of Nuclear Science and Technology Atomic Energy Research Establishment Department of Environmental Sciences Jahangirnagar University Isotope Hydrology Section Department of Nuclear Sciences and Applications International Atomic Energy Agency Groundwater Hydrology Bangladesh Water Development Board

To investigate the hydrogeochemical characteristics of groundwater 23 shallow, 30 intermediate and 38 deep wells samples were collected from Sylhet district of Bangladesh, and analyzed for temperature, pH, Eh, EC,DO, DOC, Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, SO_4^(2-), NO_3^-,HCO_3^-, SiO_2^-, Fe, Mn and As. Besides, 12 surface water samples from Surma and Kushiyara Rivers were also collected and analyzed to understand the influence into aquifers. Results revealed that, most of the groundwater samples are acidic in nature, and Na–HCO_3 is the dominant groundwater type. The mean value of temperature, EC,Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, NO_3^- and SO_4^(2-) were found within the range of permissible limits, while most of the samples exceeds the allowable limits of Fe, Mn and As concentrations. However, relatively higher concentration of Fe and Mn were found in deep water samples and reverse trend was found in case of As. The mean concentrations of As in shallow, intermediate and deep wells were 39.3, 25.3and 21.4 lg/L respectively, which varied from 0.03 to148 lg/L. From spatial distribution, it was found that Fe,Mn and As concentrations are high but patchy in northern,north-western, and south-western part of Sylhet region. The most influential geochemical process in study area were identified as silicate weathering, characterized by active cation exchange process and carbonate weathering, which thereby can enhance the elemental concentrations in groundwater. Pearson's correlation matrix, principal component analysis and cluster analysis were also employed to evaluate the controlling factors, and it was found that, both natural and anthropogenic sources were influencing the groundwater chemistry of the aquifers. However, surface water has no significant role to contaminate the aquifers,rather geogenic factors affecting the trace elemental contamination. Thus it is expected that, outcomes of this study will provide useful insights for future groundwater monitoring and

关键词： Arsenic Groundwater Hydrogeochemistry Multivariate statistics Spatial distribution

Quantification of River Bank Erosion and Bar Deposition in Chowhali Upazila, Sirajganj District of Bangladesh: A Remote Sensing Study

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Journal of Geoscience and Environment Protection 2016年第1期4卷 50-57页

作者： md. Shareful Hassan Syed Mahmud-ul-islam Center for Environmental Change Studies and Management Dhaka Bangladesh Department of Sustainable Development Environmental Science and Engineering KTH-Royal Institute of Technology Stockholm Sweden

River bank erosion is one of the frequent but the most unpredictable disasters that occur every year in Bangladesh. In this paper, Landsat TM-5 and Landsat-8 imageries from 1989 and 2015 were used to detect changes of present land use, river erosion and bar deposition in Chowhali Upazila, Sirajganj district of Bangladesh. This study reveals that human settlement, forest, seasonal crops and agriculture features decrease, while river coverage increases dramatically. About 1340 hectare areas have been eroded, while 630 hectares are deposited as channel bar in the study area over the last 26 years. Finally, an accuracy assessment is conducted between the test data and each land use feature. The overall classification accuracy was 97% and 98% in 1989 and 2015 respectively. Moreover, 98% accuracy is found in erosion while 97% is found in bar deposition areas.

关键词： GIS Remote Sensing Landsat River Erosion Change Detection Chowhali Bangladesh

Integration of Remote Sensing and GIS to Assess Vulnerability of Environmental Degradation in North-Western Bangladesh

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Journal of Geographic Information System 2015年第5期7卷 494-505页

作者： md. Shareful Hassan Syed Mahmud-ul-islam Muhammad Tauhidur Rahman Center for Environmental Change Studies and Management Dhaka Bangladesh Department of Sustainable Development Environmental Science and Engineering KTH-Royal Institute of Technology Stockholm Sweden Department of City and Regional Planning King Fahd University of Petroleum and Minerals Dhahran KSA

Environmental degradation is a burning issue in Bangladesh. The degradation process is extremely acute in the north-western part of Bangladesh due to many environmental and anthropogenic reasons. However, initiative of research work on this issue is very crucial and urgent for regional and local planning and management. In this paper, Nachole and Niamotpur Upazilas were considered as the study area to identify and quantify environmental degradation using an integrated Geographic Information System (GIS) and Remote Sensing (RS) technique. The results of the study reveal that the area is one of the most vulnerable areas in terms of land degradation that already affected local agriculture, biodiversity, water supply and overall socio-economic livelihoods. From the modelling results, about 66,301 hectares (90%) of land are vulnerable to land degradation, of which 24,736, 40,309 and 256 hectares of land were classified as severely, highly, and moderately vulnerable areas respectively. The overall image classification accuracy for all the resultant images was 95.40% while kappa coefficient was 0.94.

关键词： GIS Remote Sensing Landsat DEM Soil Degradation Bangladesh

Evaluation of Economical and Ecological Aspects of Denim Garments Dyeing with Fluorescent Dye

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Journal of Materials Science and Chemical Engineering 2013年第7期1卷 1-6页

作者： Muhammad Abdur Rashid md. Delwar Hossain Muhammad Mufidul islam md. Nakib-ul-Hasan Department of Textile Engineering Dhaka University of Engineering & Technology (DUET) Gazipur Bangladesh Department of Textile Engineering Northern University Bangladesh Dhaka Bangladesh

In this study the existing process (3 steps) and proposed process (2 steps) were evaluated during dyeing of denim fabric with fluorescent dye. It compared the effectiveness of these two processes of fluorescent dyeing in the textile industry. Here at first the grey denim fabric was pretreated by scouring and bleaching. Then the fabric was dyed in existing process i.e. through catanizing, dyeing and binding at 10% and 15% shades. Again the pretreated fabric was dyed in proposed process i.e. through catanizing and (dyeing and binding) with same shades. Then the properties of two types of dyed fabric were compared. This study provides a set of experimental results, discussion and comparison between the two processes. The results show that the proposed process has less power and time consumption and more water savings compared to existing process. So the evaluation reflected that the proposed process was much more effective than existing process of denim dyeing with fluorescent dye.

关键词： Fluorescent Dyestuff Denim Fabric Fastness Properties

Clinico-Demographic Characteristics of Intestinal Tuberculosis in Pre-Operative Unsuspected Laparotomy as Incidental Findings in Bangladesh

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Journal of Tuberculosis Research 2017年第2期5卷 139-145页

作者： md. Mizanur Rahman Ayub Ali md. Abdullah Yusuf md. Zamil Zaidur Rahim md. Mahfuzur Rahman Zahir-ul islam Gafargaon Upazilla Health Complex Mymensingh Bangladesh Shadar General Hospital Cox’s Bazar Bangladesh Department of Microbiology National Institute of Neurosciences & Hospital Dhaka Bangladesh Department of Orthopedics Combined Military Hospital Comilla Bangladesh Department of Neurosurgery National Institute of Neurosciences & Hospital Dhaka Bangladesh Railway General Hospital Dhaka Bangladesh

Background: Clinical presentation of intestinal tuberculosis is varied. It is also essential to know the clinical and demographic characteristics of incidentally detected intestinal tuberculosis patient. Objective: The purpose of the present study was to find out the clinic-demographic characteristics of intestinal tuberculosis in clinically and preoperatively unsuspected laparotomies. Methodology: This cross-sectional study was carried out in the Department of Surgery at Dhaka Medical College Hospital, Dhaka from March 2002 to March 2004 for a period of two (2) years. All the patients underwent laparotomy presented without any suspicion of pulmonary or intestinal tuberculosis were included as study population. Patients who were without the history of cough, haemoptysis, antitubercular drug therapy were included. Per operative suspicion was raised due to enlarged lymph nodes in mesentery, omental masses, ileocaecal masses, suspicious growth in ileum, omental thickening, perforation suspected by tuberculosis. Biopsy was taken from suspicious lesions. Histopathology was confirmed the tubercular lesion. Results: A total number of 300 patients under laparotomy were recruited for this study of which 38 positive cases were found in the study with a percentage of 12.7%. Maximum affected age group was 21 to 30 years which was 16 (42%) cases. Male was predominant to female which was 28 (73.7%) cases and 10 (26.3%) cases respectively. Low socioeconomic people are affected more (76.3%). Most common presentation in positive cases was acute and sub-acute intestinal obstruction 20 (52.6%) followed by intestinal perforation (26.31%). Conclusion: In conclusion young age male patient is the most commonly affected intestinal tuberculosis which is frequently presented with sub-acute intestinal obstruction among the preoperatively unsuspected laparotomy patients.

关键词： Intestinal Tuberculosis Unsuspected Laparotomy Clinic-Demographic Characteristics