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A robust composite wide area control of a DFIG wind energy system for damping inter-area oscillations

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Protection and Control of Modern Power systems 2020年第1期5卷 280-289页

作者： ayyarao s.l.v.tummala Department of EEE GMR Institute of TechnologyRajam 532127India

This paper presents a novel composite wide area control of a DFIG wind energy system which combines the Robust Exact Differentiator(RED)and Discontinuous Integral(DI)control to damp out inter-area *** generates the real-time differentiation of a relative speed signal in a noisy environment while DI control,an extension to a twisting algorithm and PID control,develops a continuous control signal and hence reduces *** proposed control is robust to disturbances and can enhance the overall stability of the *** proposed composite sliding mode control is evaluated using a modified benchmark two-area power system model with wind energy *** results under various operating scenarios show the efficacy of the proposed approach.

关键词： DFIG Wide area control Wind energy system sliding mode control

A Two-stage Kalman Filter for Cyber-attack Detection in Automatic Generation Control system

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Journal of Modern Power systems and Clean Energy 2022年第1期10卷 50-59页

作者： ayyarao s.l.v.tummala Ravi Kiran Inapakurthi GMR Institute of Technology RajamSrikakulamAndhra PradeshIndia Raghu Engineering College DakamarriVisakhapatnamAndhra PradeshIndia

Communication plays a vital role in incorporating smartness into the interconnected power ***,historical records prove that the data transfer has always been vulnerable to *** these cyber-attacks are identified and cordoned off,they may lead to black-out and result in national security *** paper proposes an optimal two-stage Kalman filter(OTs-KF)for simultaneous state and cyber-attack estimation in automatic generation control(AGC)***/cyber-attacks are modeled as unknown inputs in the AGC *** types of cyber-attacks,i.e.,false data injection(FDI),data replay attack,denial of service(Dos),scaling,and ramp attacks,are injected into the measurements and estimated using *** the load variations of each area are seldom available,OTs-KF is reformulated to estimate the states and outliers along with the load variations of the *** proposed technique is validated on the benchmark two-area,three-area,and five-area power system *** simulation results under various test conditions demonstrate the efficacy of the proposed filter.

关键词： Cyber-security automatic generation control(AGC) load frequency control false data injection cyber-attack detection

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Observer based sliding mode frequency control for multi-machine power systems with high renewable energy

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Journal of Modern Power systems and Clean Energy 2018年第3期6卷 473-481页

作者： ayyarao s.l.v.tummala Ravikiran INAPAKURTHI P.v.RAMANARAO Department of Electrical and Electronic Engineering GMR Institute of Technology Department of Electrical and Electronic Engineering University College of Engineering and TechnologyANUGuntur India

With the global consciousness of climate change, renewable energy systems are prioritized over the conventional energy systems. The deep injection of renewables into the power systems is creating several challenges to the grid due to wide variations in their output power depending on the time of the day, weather etc. Of these challenges, frequency change plays a vital role in maintaining the power quality. This paper presents a novel sliding mode controller with non-linear disturbance observer to effectively mitigate the wide changes in the frequency. A sliding mode surface based on estimated disturbance along with states is designed. A sliding mode control law is proposed to compensate disturbances including variations in renewables, load and parameters under mismatched uncertainties. The proposed observer based controller is tested for three area multi-machine power system in MATlAB/simulink. The simulated results proved to alleviate the frequency variations effectively compared to the conventional controllers.

关键词： Renewable energy Disturbance observer sliding mode control Disturbance compensation Frequency control

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Delayed cementless total hip arthroplasty for neglected dislocation of hip combined with complex acetabular fracture and deficient bone stock

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Chinese Journal of Traumatology 2012年第6期15卷 370-372页

作者： Ashok s Gavaskar Naveen Chowdary tummala Department of Adult Joint Reconstructive surgery Parvathy HospitalSunil's OrthoworldRailway Colony IIIStreetAminjikaraiChennai 600029TamilnaduIndiaar Dhruv Clinics Chennai 600094TamilnaduIndia

Total hip arthroplasty （THA） for an un- treated acetabular fracture is technically challenging and the long-term result is not so favorable. A 45-year-old fe- male patient with untreated column and comminuted poste- rior wall fracture of the acetabulum was treated in our insti- tution by reconstruction of the posterior wall using iliac strut autograft and plate stabilization of the posterior col- umn with cancellous grafting and cementless THA in a single stage. At 3 years＇ follow-up, the patient was independently mobile without limb length discrepancy. Radiological evalu-ation showed well integrated components and bone grafts. No evidence of aseptic loosening or osteolysis was found. This report aims to emphasize that bony acetabular recon- struction allows the use of primary hip components, which improves prosthesis longevity and preserves bone stock for a future revision.

关键词： Acetabulum Fractures, bone Hipdislocation Arthroplasty, replacement, hip

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EUs guided fine needle aspiration is useful in diagnostic evaluation of indeterminate proximal biliary strictures

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Open Journal of Gastroenterology 2012年第2期2卷 33-39页

作者： Naveen B. Krishna Pavan tummala Jennifer l. labundy Banke Agarwal Division of Gastroenterology and Hepatology Saint Louis University School of Medicine Saint Louis USA

Background and Aim: Determination of the etiology of proximal biliary strictures (PBs) still remains a challenge. Even though EUs-FNA is potentially useful, its role in diagnostic evaluation of PBs is still not established due to a lack of sufficient data. We sought to determine the performance characteristics of EUs-FNA in patients with obstructive jaundice (ObJ) and PBs. Patients and Methods: This is a retrospective analysis and included patients with ObJ and PBs with non-diagnostic brush cytology, who underwent EUs-FNA in our university based practice from March 2002 to February 2009. We evaluated the final diagnoses in study patients and the performance characteristics of EUs-FNA for identifying malignant PBs. Final diagnosis was based on surgical pathology or clinical follow-up of at least 12 months. Results: The study included 28 patients (17 male, 11 female) with mean age of 62.4 ± 14.9 years. The strictures ranged from 10 - 70 mm in length. CT scan identified a hilar mass in 9 patients. EUs-FNA identified malignancy in 12 patients. 18 patients were finally diagnosed to have a malignant stricture and 10 patients had a benign stricture. There were 6 false negative diagnoses. The accuracy of EUs-FNA for diagnosis of cholangiocarcinoma was 78.6%, with 66.6% sensitivity, 100% specificity, 62.5% NPv and 100% PPv. Conclusions: EUs-FNA can diagnose malignancy in 66.6% of jaundiced patients with PBs and non-diagnostic brush cytology and may have a role in their further diagnostic evaluation.

关键词： EUs-FNA Cholangiocarcinoma Proximal Biliary strictures

Tuberculous Arthritis of Knee Presenting as Bakers Cyst: A Case Report

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International Journal of Clinical Medicine 2014年第6期5卷 319-324页

作者： tummala venkata suresh Babu Kopuri Ravi Kiran Kora Deepti Department of Orthopaedics Dr. PSIMS & RF Vijayawada India Department of Radiodiagnosis Nagarjuna Superspeciality Hospitals Vijayawada India

Tuberculosis (TB) is no longer confined to undeveloped or developing nations. Today, one third of world’s population suffers from tuberculosis. Tuberculosis (TB) of the musculoskeletal system is an uncommon infection caused by tuberculous bacilli and constitutes 1%-5% of all forms of TB. 30% of skeletal TB involves the joints, the knee being the third most commonly affected after the spine and the hip. Knee tuberculosis commonly presents as synovitis or arthritis. Baker’s cyst is a rather rare complication of knee joint tuberculosis. We report a case of a 50-year-old man with tuberculous arthritis of the right knee who presented to us as baker’s cyst.

关键词： Tuberculosis Bakers Cyst loose Bodies

Advances in High Density Interconnect substrate and Printed Wiring Board Technology

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Advances in High Density Interconnect Substrate and Printed ...

第六届电子封装技术国际学术会议

作者： venky sundaram Boyd Wiedenman Rao tummala Packaging Research Center Georgia Institute of technology Packaging Research Center Georgia Institute of technology Packaging Research Center Georgia Institute of technology

The substrate or printed wiring board (PWB), as the largest component in electronic packages and systems, is performing an increasingly critical role in advancedpackages, high performance electronic s

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橙足负泥虫种群系统的灵敏度分析

生态学报 1987年第2期7卷 129-137页

作者：李典谟,R.l.tummala 中国科学院动物研究所美国密执安州立大学

灵敏度分析应用到密度制约和非密度制约种群系统。输入扰动是通过在计算机程序里增加或降低20％的早春成虫来进行的。参数扰动是通过在模拟一百天中变动20％早期、中期、晚期的温度来进行的。结果列在表1。结果表明具有密度制约成活率... 详细信息

灵敏度分析应用到密度制约和非密度制约种群系统。输入扰动是通过在计算机程序里增加或降低20％的早春成虫来进行的。参数扰动是通过在模拟一百天中变动20％早期、中期、晚期的温度来进行的。结果列在表1。结果表明具有密度制约成活率的系统比非密度制约的系统更稳定,文内进行了进一步讨论。

关键词：种群系统负泥虫李典密度制约 TOTAl AUX 灵敏度分析数值分析

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论计算机化的病虫害管理系统的原理

生态学报 1983年第3期3卷 252-261页

作者：李典谟,R.l.tummala,D.l.Haynes 中国科学院动物研究所美国密执安州立大学昆虫系与系统科学系美国密执安州立大学昆虫系与系统科学系中国访美学者原单位为中国科学院动物研究所

由于现代系统理论引入害虫防治的领域,并结合计算机技术的发展,害虫管理系统也有了飞跃的进步。本文不仅讨论了发展现代害虫管理系统的原理和若干理论问题,而且还比较了中国传统的预测预报网与现代建立在计算机网络上的联机(on line)害... 详细信息

由于现代系统理论引入害虫防治的领域,并结合计算机技术的发展,害虫管理系统也有了飞跃的进步。本文不仅讨论了发展现代害虫管理系统的原理和若干理论问题,而且还比较了中国传统的预测预报网与现代建立在计算机网络上的联机(on line)害虫管理系统,并对今后发展提出了作者的看法。害虫综合管理(或防治)的概念,随着时代的发展,也赋予新的含意,系统理论引入害虫防治的相关领域,则是认识论上的一大提高,也是学科发展和学科互相渗透的必然结果。

关键词：害虫管理计算机化可控因子病虫害病虫草害