267 research outputs found
Robust adaptive sampled-data control design for MIMO systems: Applications in cyber-physical security
No full textThis dissertation extends the L1 adaptive control theory to sampled-data (SD) framework. Multi-input multi-output non-square (underactuated) systems are considered with different sampling rates for inputs and outputs. The sampled-data framework allows to address non-minimum phase systems, subject to less restrictive assumptions as compared to continuous time framework. It is shown that the closed-loop system can recover the response of a continuous-time reference system as the sampling time of the SD controller tends to zero. In this thesis, the L1 sampled data adaptive controller is integrated with the Simplex fault-tolerant architecture for resilient control of cyber-physical systems (CPSs). Detection and mitigation of zero-dynamics attacks are addressed and validated in flight tests of a quadrotor in Intelligent Robotics Laboratory of UIUC. The experiments show that the multirate L1 controller can e effectively detect stealthy zero-dynamics attacks and recover the stability of the perturbed system, where the single-rate conventional L1 adaptive controller fails.
From the perspective of applications, the dissertation considers navigation and control of autonomous vehicles and proposes a two-loop framework, in which the high-level reference commands are limited by a saturation function, while the low-level controller tracks the reference by compensating for disturbances and uncertainties. A class of nested, uncertain, multi-input multi-output (MIMO) systems subject to reference command saturation, possibly with non-minimum phase zeros, is considered. Robust stability and performance of the overall closed-loop system with command saturation and multirate L1 adaptive controller are analyzed.
Finally, a systematic analysis and synthesis method is proposed for the optimal design of filters in the L1 adaptive output-feedback structure, where the lowpass filter is the key to the trade-off between the performance and robustness of the closed-loop system. An optimization problem is formulated using the constraint on the input time-delay margin and a cost-function based on mixed L1/H2-norm performance measure. The optimization problem can be efficiently solved using linear/quadratic programming.
We note that the framework of this dissertation and the multi-loop problem formulation of navigation and control of autonomous systems provide suitable synthesis and analysis tools for autonomous cyber-physical systems (CPSs), including self-driving cars, unmanned aerial vehicles (UAVs), and industrial/medical robots, to name just a few. The SD design facilitates the implementation of control laws on digital computers in CPSs, where the input/output signals are available at discrete time instances with different sampling rates.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2020-12-01The student, Hamidreza Jafarnejadsani, accepted the attached license on 2018-11-19 at 12:24.The student, Hamidreza Jafarnejadsani, submitted this Dissertation for approval on 2018-11-19 at 13:00.This Dissertation was approved for publication on 2018-11-21 at 10:30.DSpace SAF Submission Ingestion Package generated from Vireo submission #13099 on 2019-02-07 at 14:17:36Made available in DSpace on 2019-02-07T20:35:58Z (GMT). No. of bitstreams: 2
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Previous issue date: 2018-11-21Embargo set by: Seth Robbins for item 109822
Lift date: 2021-02-07T20:36:09Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 109822
Lift date: 2021-02-07T20:39:46Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 109822
Lift date: 2021-02-07T20:44:35Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 109822 on 2021-02-08T10:15:25Z
The Ukraine War: The View from Iran
No full textWhy has Iran chosen to clandestinely have closer ties with Russia in the Ukraine War
Challenges to Iran's role in Iraq in the post-Soleimani era: complex rivalries, fragmented alliances, declining soft power
No full textOn January 3, 2020, the Iranian Quds Force commander, Maj. Gen. Qassem Soleimani, was assassinated by the United States in Iraq. He was considered the mastermind behind Iran's regional strategy, especially in Syria and Iraq. A year and a half later, the Islamic Republic continues to wield considerable influence in Iraq, and Iran-backed militias continue to violently pressure US forces to leave Iraq. However, Iran now faces a series of serious challenges that are directly and indirectly related to Soleimani's death. In the geopolitical and economic spheres, the influence of Iran's rivals in Iraq has increased, while Tehran’s room for maneuver has become increasingly limited. In the political arena, divisions among Iran-backed forces in Iraq have increased, while Iran's direct influence over the Iraqi government has been declining. At the same time, rising anti-Iranian sentiments among the Iraqi people have reduced Iran's social capital in the neighboring country. The combination of these factors seems to be limiting Iran's influence in Iraq. The EU should build upon this opportunity to support a strong Iraqi government that pursues a multi-vector foreign policy. (author's abstract
Iran's multi-faceted strategy in Deir ez-Zor: from fighting terrorism to creating a zone of influence
No full textOne aspect of Iran’s involvement in Syria that has come under the spotlight recently is Iran's growing presence and activities in Deir ez-Zor province in eastern Syria. Not only has Iran established its military presence in the region by deploying troops and constructing military bases, it has also been active in social, cultural, and economic spheres. Many observers believe that Iran's goal is to establish a "land corridor" to connect the country to Lebanon via Iraq and Syria. Others argue that Iran is attempting to expand its ideological influence in Deir ez-Zor by promoting Shi'ism. However, the Islamic Republic is pursuing a multifaceted strategy in the area. Tehran wants to establish an economic corridor to the Mediterranean to play a role in China's Belt and Road Initiative (BRI). Iran is also trying to create a zone of influence in Syria's east while strengthening its deterrence against Israel and the United States. Preventing the revival of the so-called Islamic State (IS) remains another priority. (author's abstract
Infestation and pathological lesions of some lymph nodes induced by Linguatula serrata nymphs in sheep slaughtered in Shahrekord Area (Southwest Iran)
No full textAbstractObjectiveTo determine the infection rates of mesenteric and mediastinal lymph nodes in relation to Linguatula serrata (L. serrata) nymphs.MethodsIn the present study, mesenteric and mediastinal lymph nodes of 200 sheep with different sex and age that were slaughtered in a Shahrekord slaughterhouse were collected. The lymph nodes were examined macroscopically and for histopathological examination, tissue samples were taken from the gross lesions processed routinely by paraffin method and stained with hematoxylin and eosin.ResultsOut of 200 examined sheep, the mesenteric lymph nodes in 18 sheep (9%) and the mediastinal lymph nodes of 9 sheep (4.5%) were infected by L. serrata nymphs. The infection rate increased with age, but no significant difference was observed between males and females or the two types of lymph nodes (P > 0.01). Different nonspecific gross and macroscopic lesions were seen in infected lymph nodes. L. serrata nymph sections were observed in some histopathological slides.ConclusionsIt is concluded that the sheep may play an important role in linguatulosis of final hosts and human beings in this region
Author Response
No full textRahmatinejad Z, Hoseini B, Pourmand A, Reihani H, Rahmatinejad F, Eslami S, Author Response. Indian J Crit Care Med 2024;28(2):183-184
Neurogenic pulmonary edema (NPE) following head injury in a 20 years old man
No full textزمینه و هدف: ادم ریه نروژنیک ((Neurogenic pulmonary edema=NPE یکی از عوارض نسبتاً نادر و تهدید کننده حیات در بیماران با ضربه مغزی می باشد. این عارضه در جوانان با خونریزی مغزی یا طناب نخاعی، تروما، تومورها، تشنج ها و یا عفونت ها دیده می شود. خصوصیت مشترک اتیولوژی های مختلف، افزایش فشار داخل مغز می باشد. گزارش مورد: آقایی 20 ساله بعد از سقوط از ارتفاع 10 متری دچار ضربه مغزی و کاهش سطح هوشیاری شده و بعد از 5 ساعت دچار ادم ریه نروژنیک می شود. در این گزارش در باره معرفی (Presentation)، آسیب شناسی و اداره بیمار (Management) بحث می کنیم تا پزشک معالج متوجه این بیماری و تشخیص افتراقی آن در زمان مراجعه باشد. نتیجه گیری: ادم ریه نروژنیک در بیماران با ضربه مغزی که دچار تنگی نفس ناگهانی و کاهش نسبت /Fio2 Pao2 می شوند باید مد نظر باشد. مرگ و میر در این بیماران بالاست اما اگر سریعاً درمان مناسب انجام گردد موجب بهبودی سریع می شود
Iran-China Cooperation in the Silk Road Economic Belt: From Strategic Understanding to Operational Understanding
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