scholarly journals DETECTION OF CHAOS IN SOME LOCAL REGIONS OF PHASE PORTRAITS USING SHANNON ENTROPIES

2004 ◽  
Vol 14 (04) ◽  
pp. 1493-1499 ◽  
Author(s):  
BINGO WING-KUEN LING ◽  
CHARLOTTE YUK-FAN HO ◽  
PETER KWONG-SHUN TAM
Keyword(s):  
Unit Circle ◽  
Digital Filters ◽  
Second Order ◽  
The State ◽  
Phase Portraits ◽  
Type Ii ◽  
State Variables ◽  
Type Iii ◽  
Special Values ◽  
Symbolic Sequences

This letter demonstrates the use of Shannon entropies to detect chaos exhibited in some local regions on the phase portraits. When both eigenvalues of the second-order digital filters with two's complement arithmetic are outside the unit circle, the Shannon entropies of the state variables are independent of the initial conditions and the filter parameters, except for some special values of the filter parameters. At these special values, the Shannon entropies of the state variables are relatively small. The state trajectories corresponding to these filter parameters either exhibit random-like chaotic behaviors in some local regions or converge to some fixed points on the phase portraits. Hence, by measuring the Shannon entropies of the state variables, these special state trajectory patterns can be detected. For completeness, we extend the investigation to the case when the eigenvalues of the second-order digital filters with two's complement arithmetic are complex and are inside or on the unit circle. It is found that the Shannon entropies of the symbolic sequences for the type II trajectories may be higher than that for the type III trajectories, even though the symbolic sequences of the type II trajectories are periodic and have limit cycle behaviors, while that of the type III trajectories are aperiodic and have chaotic behaviors.

Approximate Re-Analysis of Dynamic Systems

1994 ◽  
Author(s):  
Qiushi Cao ◽  
Prakash Krishnaswami
Keyword(s):  
Dynamic Analysis ◽  
Mechanical System ◽  
Dynamic Systems ◽  
Second Order ◽  
The State ◽  
Weighted Sum ◽  
State Variables ◽  
Taylor’S Series

Abstract Dynamic analysis of a mechanical system is extremely time consuming. It may be desirable for a designer to approximate the state variables at a new design if state and sensitivity information at previous designs are already available. In this paper, several approximate re-analysis schemes have been explored. These include Taylor’s series of first and second order, weighted sum of state variables and weighted sum of Taylor’s series. The results show that Taylor’s series of second order can predict state variables quite well if the perturbation in design is relatively small. Weighted sum approximation based on state variables can generally give acceptable results, while weighted Taylor’s series is generally unsatisfactory if the perturbation is large.

scholarly journals CHAOTIC BEHAVIORS OF A DIGITAL FILTER WITH TWO'S COMPLEMENT ARITHMETIC AND ARBITRARY INITIAL CONDITIONS AND ORDER

2004 ◽  
Vol 14 (07) ◽  
pp. 2425-2430 ◽  
Author(s):  
BINGO WING-KUEN LING ◽  
WAI-FUNG HUNG ◽  
PETER KWONG-SHUM TAM
Keyword(s):  
Digital Filter ◽  
Initial Conditions ◽  
The State ◽  
State Variables ◽  
System Matrix ◽  
Symbolic Sequences ◽  
Simulation Results

This letter shows some counter-intuitive simulation results that the symbolic sequences and the state variables of a digital filter with two's complement arithmetic and arbitrary initial conditions and order will be eventually zero when all the filter parameters are even numbers, no matter the system matrix of the filter is stable or not.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

Non Linear State and Parameters Estimation in Chemical Processes: Analysis and Improvement of Three Estimation Structures Applied to a CSTR

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Héctor Botero ◽  
Hernán Álvarez
Keyword(s):  
Parameter Estimation ◽  
Chemical Process ◽  
Chemical Processes ◽  
The State ◽  
Convergence Speed ◽  
Parameters Estimation ◽  
State Variables ◽  
Input Output ◽  
On Line ◽  
Linear State

This paper proposes a new composite observer capable of estimating the states and unknown (or changing) parameters of a chemical process, using some input-output measurements, the phenomenological based model and other available knowledge about the process. The proposed composite observer contains a classic observer (CO) to estimate the state variables, an observer-based estimator (OBE) to obtain the actual values of the unknown or changing parameters needed to tune the CO, and an asymptotic observer (AO) to estimate the states needed as input to the OBE. The proposed structure was applied to a CSTR model with three state variables. With the proposed structure, the concentration of reactants and other CSTR parameters can be estimated on-line if the reactor and jacket temperatures are known. The procedure for the design of the proposed structure is simple and guarantees observer convergence. In addition, the convergence speed of state and parameter estimation can be adjusted independently.

scholarly journals A Robust Observer—Based Adaptive Control of Second—Order Systems with Input Saturation via Dead-Zone Lyapunov Functions

Computation ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 82
Author(s):  
Alejandro Rincón ◽  
Gloria M. Restrepo ◽  
Fredy E. Hoyos
Keyword(s):  
Lyapunov Functions ◽  
Dead Zone ◽  
Tracking Error ◽  
Input Saturation ◽  
Chemical Reactor ◽  
Second Order ◽  
Control Law ◽  
Compact Set ◽  
State Variables ◽  
Robust Observer

In this study, a novel robust observer-based adaptive controller was formulated for systems represented by second-order input–output dynamics with unknown second state, and it was applied to concentration tracking in a chemical reactor. By using dead-zone Lyapunov functions and adaptive backstepping method, an improved control law was derived, exhibiting faster response to changes in the output tracking error while avoiding input chattering and providing robustness to uncertain model terms. Moreover, a state observer was formulated for estimating the unknown state. The main contributions with respect to closely related designs are (i) the control law, the update law and the observer equations involve no discontinuous signals; (ii) it is guaranteed that the developed controller leads to the convergence of the tracking error to a compact set whose width is user-defined, and it does not depend on upper bounds of model terms, state variables or disturbances; and (iii) the control law exhibits a fast response to changes in the tracking error, whereas the control effort can be reduced through the controller parameters. Finally, the effectiveness of the developed controller is illustrated by the simulation of concentration tracking in a stirred chemical reactor.

scholarly journals Perforator preservation technologies (PPT) based on a new neuro-interventional classification in endovascular treatment of perforator involving aneurysms (piANs)

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chen Li ◽  
Ao-Fei Liu ◽  
Han-Cheng Qiu ◽  
Xianli Lv ◽  
Ji Zhou ◽  
...  
Keyword(s):  
Endovascular Therapy ◽  
Saccular Aneurysm ◽  
Type I ◽  
Type Ii ◽  
Fusiform Aneurysm ◽  
Type Iii ◽  
Perforating Artery ◽  
Protection Technology ◽  
Perforating Arteries

Abstract Background Treatment of perforator involving aneurysm (piAN) remains a challenge to open and endovascular neurosurgeons. Our aim is to demonstrate a primary outcome of endovascular therapy for piANs with the use of perforator preservation technologies (PPT) based on a new neuro-interventional classification. Methods The piANs were classified into type I: aneurysm really arises from perforating artery, type II: saccular aneurysm involves perforating arteries arising from its neck (IIa) or dome (IIb), and type III: fusiform aneurysm involves perforating artery. Stent protection technology of PPT was applied in type I and III aneurysms, and coil-basket protection technology in type II aneurysms. An immediate outcome of aneurysmal obliteration after treatment was evaluated (satisfactory obliteration: the saccular aneurysm body is densely embolized (I), leaving a gap in the neck (IIa) or dome (IIb) where the perforating artery arising; fusiform aneurysm is repaired and has a smooth inner wall), and successful perforating artery preservation was defined as keeping the good antegrade flow of those perforators on postoperative angiography. The periprocedural complication was closely monitored, and clinical and angiographic follow-ups were performed. Results Six consecutive piANs (2 ruptured and 4 unruptured; 1 type I, 2 type IIa, 2 type IIb, and 1 type III) in 6 patients (aged from 43 to 66 years; 3 males) underwent endovascular therapy between November 2017 and July 2019. The immediate angiography after treatment showed 6 aneurysms obtained satisfactory obliteration, and all of their perforating arteries were successfully preserved. During clinical follow-up of 13–50 months, no ischemic or hemorrhagic event of the brain occurred in the 6 patients, but has one who developed ischemic event in the territory of involving perforators 4 h after operation and completely resolved within 24 h. Follow-up angiography at 3 to 10M showed patency of the parent artery and perforating arteries of treated aneurysms, with no aneurysmal recurrence. Conclusions Our perforator preservation technologies on the basis of the new neuro-interventional classification seem feasible, safe, and effective in protecting involved perforators while occluding aneurysm.

scholarly journals Outcomes of one-stage reconstruction for chronic multiligament injuries of knee

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Tarun Goyal ◽  
Souvik Paul ◽  
Sushovan Banerjee ◽  
Lakshmana Das
Keyword(s):  
Cruciate Ligament ◽  
Lysholm Score ◽  
Activity Level ◽  
Type Ii ◽  
Hamstring Tendons ◽  
Peroneus Longus ◽  
Type Iii ◽  
Type Iv ◽  
Ikdc Score

Abstract Purpose This article aims to evaluate patterns of chronic multiligament injuries and outcomes of treatment with single-stage reconstruction using autografts. Methods All patients with clinicoradiologically diagnosed multiligament knee injury (MKI) were included in this prospective observational study. As the time since injury was more than 6 weeks in all of the patients, they were categorized as having chronic MKI. Patients were assessed clinically for laxity, and the diagnosis was confirmed radiologically. Ipsilateral hamstring tendons were used for medial collateral ligament (MCL) or posterolateral corner reconstruction in a patient with Schenck knee dislocation (KD) type III. In these cases, the posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) were reconstructed by using the peroneus longus and contralateral hamstring tendons respectively. Ipsilateral hamstring tendons were used for ACL reconstruction and an ipsilateral peroneus longus tendon graft was used for reconstruction of the PCL in a KD type II injury. In two cases of KD type IV injury, the lateral laxity was only grade II and was managed conservatively; the rest of the ligaments were addressed like a KD type III injury. Outcome evaluation was done using a visual analogue scale (VAS) for pain, International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity level, preoperatively and postoperatively at 2 years’ follow-up. Results A total of 27 patients of mean age 33.48 ± 9.9 years with MKI were included in the study. The patients were classified as eight KD type II, 17 KD type III, and two KD type IV. The majority of the patients had associated meniscal (59.2%) or chondral (40.7%) injuries. At the 2 years’ follow-up visit, there were significant improvements in VAS score (p = 0.0001) IKDC score (p = 0.0001), Lysholm score (p = 0.0001), and range of motion (p = 0.001). None of the patients had residual laxity on clinical examination of the knee joint at the 2 years’ follow-up. All but two of the patients went back to their previous activity level. These two patients had progressive knee arthritis and needed knee arthroplasty. Conclusion Single-stage surgical reconstruction for chronic MKI has favourable functional outcomes. Level of evidence Level IV, case series.

scholarly journals Intracellular and Extracellular Markers of Lethality in Osteogenesis Imperfecta: A Quantitative Proteomic Approach

2021 ◽  
Vol 22 (1) ◽  
pp. 429
Author(s):  
Luca Bini ◽  
Domitille Schvartz ◽  
Chiara Carnemolla ◽  
Roberta Besio ◽  
Nadia Garibaldi ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Type I Collagen ◽  
Type I ◽  
Tandem Mass ◽  
Type Ii ◽  
Type Iii ◽  
Bioinformatic Tools ◽  
Proteomic Approach ◽  
Fibrillin 1 ◽  
Heritable Disorder

Osteogenesis imperfecta (OI) is a heritable disorder that mainly affects the skeleton. The inheritance is mostly autosomal dominant and associated to mutations in one of the two genes, COL1A1 and COL1A2, encoding for the type I collagen α chains. According to more than 1500 described mutation sites and to outcome spanning from very mild cases to perinatal-lethality, OI is characterized by a wide genotype/phenotype heterogeneity. In order to identify common affected molecular-pathways and disease biomarkers in OI probands with different mutations and lethal or surviving phenotypes, primary fibroblasts from dominant OI patients, carrying COL1A1 or COL1A2 defects, were investigated by applying a Tandem Mass Tag labeling-Liquid Chromatography-Tandem Mass Spectrometry (TMT LC-MS/MS) proteomics approach and bioinformatic tools for comparative protein-abundance profiling. While no difference in α1 or α2 abundance was detected among lethal (type II) and not-lethal (type III) OI patients, 17 proteins, with key effects on matrix structure and organization, cell signaling, and cell and tissue development and differentiation, were significantly different between type II and type III OI patients. Among them, some non–collagenous extracellular matrix (ECM) proteins (e.g., decorin and fibrillin-1) and proteins modulating cytoskeleton (e.g., nestin and palladin) directly correlate to the severity of the disease. Their defective presence may define proband-failure in balancing aberrances related to mutant collagen.

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