Block Operator Research Articles

Electromagnetic Steklov eigenvalues: existence and distribution in the self-adjoint case

In previous works, it was suggested to use Steklov eigenvalues for Maxwell equations as target signature for nondestructive testing, and it was recognized that this eigenvalue problem cannot be reformulated as a standard eigenvalue problem for a compact operator. Consequently, a modified eigenvalue problem with the desired properties was proposed. We report that apart for a countable set of particular frequencies, the spectrum of the original self-adjoint eigenvalue problem consists of three disjoint parts: The essential spectrum consisting of the origin, an infinite sequence of positive eigenvalues which accumulate only at infinity and an infinite sequence of negative eigenvalues which accumulate only at zero. The analysis is based on a suitable topological decomposition, a representation of the operator as block operator and Schur-factorizations. For each Schur-complement, the existence of an infinite sequence of eigenvalues is proven via an intermediate value technique. The modified eigenvalue problem arises as limit of one Schur-complement.

Autonomous ICDs Optimize Production in Singue Field, Ecuador

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 210417, “Autonomous ICD Introduction in Singue Field, Ecuador: Completion Methodology and Production Evaluation,” by Alejandro Chacon, SPE, Georgina Corona, and Juan Pico, Halliburton, et al. The paper has not been peer reviewed. _ Autonomous-inflow-control-device (AICD) technology, design methodology, and production-performance evaluation for AICD completions were applied for the first time in multiple horizontal wells of the Singue oilfield development in Ecuador. The analysis described in the complete paper covered the complete cycle, from reservoir modeling, completion design, post-drilling match, calibration, and production-performance analysis. Background and Field Information Singue is a field in a tropical rainforest in the Sucumbios province of Ecuador. The first well in the Singue field was drilled in February 1991. Lower U was the target reservoir in this first well. The well was drilled on the basis of seismic 2D data acquired from 1979 to 1989. Field cumulative oil production between 1991 and 1997 was 447,000 bbl. The field then was shut in until 2012, when Gente Oil Company was assigned as the operator of Block 53. Despite heavy field-development investment, a cumulative oil production of 8 million bbl was generated until 2018. Alternate completion techniques were considered to increase oil production by drilling horizontal wells. Water breakthrough was the challenge in these wells. The field has strong support from a water aquifer. An additional challenge in this area was the environmental sensitivity of the Amazon region to produced-water disposal. A horizontal completion with inflow-control technology to restrict water was considered as a mitigation measure. The first horizontal well, AH1, was drilled in 2019; it included swell packers and AICDs to balance the oil and control and restrict water at breakthrough. The second well, BH2, was drilled in 2020; the third and fourth wells were drilled in 2021 with similar completion technology. These wells were drilled in the Lower U reservoir, which has an average oil API gravity of 22.8. This reservoir is considered a consolidated sandstone with no sand production. Fluidic-Diode AICD Technology AICDs have a similar performance to traditional ICDs during the initial oil-production phase of the well before the onset of unwanted fluids (water/gas). During oil production, AICDs induce a low-pressure differential that allows balancing the flow across the completion. Therefore, they also provide the benefit of delaying the onset of water or gas. However, this technology offers additional benefits. In contrast to ICDs, AICDs induce a higher restriction for water or gas by creating a greater pressure differential across the devices for these fluids, which reduces the flow rate when compared with traditional ICDs.

Representation and normality of $$*$$-paranormal absolutely norm attaining operators

In this article, we give a representation of absolutely norm attaining $$*$$ -paranormal operators. More specifically, we prove that every $$*$$ -paranormal absolutely norm attaining operator T can be decomposed as $$U\oplus D$$ , where U is a direct sum of scalar multiples of unitary operators and D is an upper triangular block operator matrix. Later, we provide a sufficient condition under which a $$*$$ -paranormal absolutely norm attaining operator is normal.

A bilateral attention based generative adversarial network for DIBR 3D image watermarking

This paper presents a bilateral attention based generative adversarial network (BAGAN) for depth-image-based rendering (DIBR) 3D image watermarking to protect the image copyright. Convolutional block operations are employed to extract main image features for robust watermarking, but embedding watermark into some features will degrade image quality much. To relieve this kind of image distortion, the bilateral attention module (BAM) is utilized by mining correlations of the center view and the depth map to compute attention of the 3D image for guiding watermark to distribute over different image regions. Since a modality gap exists between the center view and the depth map, a cross-modal feature fusion module (CMFFM) is designed for BAM to bridge the cross-view gap. Because the depth map has lots of flat background information including many redundant features, to prune them, the depth redundancy elimination module (DREM) is used for cross-view feature fusion. In the decoder, two extractors with the same structure are built to recover watermark from the center view and the synthesized view, respectively. In addition, the discriminator is supposed to build a competitive relationship with the encoder to increase the image quality. The noise sub-network is used to train different image attacks for robustness. Extensive experimental results have demonstrated that the proposed BAGAN can obtain higher watermarking invisibility and robustness compared with existing DIBR 3D watermarking methods. Ablation experiments have also proven the effectiveness of DREM, CMFFM and BAM on BAGAN.

Ultrasound-Guided Modified Thoracolumbar Fascial Plane Block in Tianji Robot-Assisted Lumbar Internal Fixation: A Prospective, Randomized, and Non-Inferiority Study.

Ultrasound-guided modified thoracolumbar fascial plane block (MTLIP) has been reported effective for postoperative pain control following lumbar surgery. Although trauma of the Tianji robot-assisted lumbar internal fixation is reduced, the degree of pain cannot be ignored.MTLIP may improve operation efficiency and reduce puncture complications.This study aimed to explore whether MTLIP is not inferior to thoracolumbar fascial plane block (TLIP) in the treatment of lumbar internal fixation. This prospective double-blinded, non-inferiority randomized trial enrolled patients underwent Tianji robot-assisted lumbar internal fixation between April and August 2022 to either MTLIP or TLIP. The primary outcome was an effective dermatomal block area after 30 min. Secondary outcomes included the numeric rating scale (NRS) scores, nerve block operation time, puncture times, image clarity, patient satisfaction, intraoperative opioid consumption, complications/adverse reactions, and Oswestry Disability Index (ODI). Sixty participants were randomized to MTLIP (n=30) and TLIP (n=30). The effective dermatomal block area 30 min after block was non-inferior in the MTLIP group (283.6 ± 62.6 cm2) compared with the TLIP group (261.4±53.2 cm2) (P=0.145; estimated mean difference: -22.17, 95% CI: -52.19, 7.85; smaller than the non-inferiority margin of 39.5). Compared with TLIP, MTLIP showed shorter operation time, smaller puncture times, and better target definition and satisfaction scores (all P<0.001). Sufentanil amount, remifentanil amount, PCIA sufentanil dosage, parecoxib amount, NRS scores (increased with time in the two groups but without inter-group differences), and complications were not significantly different between the two groups (all P>0.05). This non-inferiority trial supports the hypothesis that MTLIP yields a non-inferior effective dermatomal block area compared with TLIP for Tianji robot-assisted lumbar internal fixation. Chinese Clinical Trial Registry (ChiCTR2200058687);.

B-essential spectra of 2 × 2 block operator matrix pencils

Abstract The paper is devoted to the study of the relative B-essential spectra of 2 × 2 {2\times 2} unbounded operator matrix pencils defined with nondiagonal domain. The main tool used to prove the results is the Frobenuis–Schur factorization associated with this kind of operator matrix which has proven very useful in dealing with stability analysis in the theory of B-Fredholm operators pencils. Therefore, the theoretical results are tested in pencil transport integro-differential equation with specific boundary conditions.

Some Spectral Characteristic Numbers of Direct Sum of Operators

In the present study, firstly, some algebraic inequalities are proved, which will be used later. By making use of these relations, some evaluations are found related the gaps between norm and numerical radius, spectral radius and Crawford number for diagonal block operator matrices on the infinite direct sum of Hilbert spaces. Later on, the gaps between some spectral characteristic numbers (operator norm, lower and upper bounds of spectrum set and numerical radius) of the infinite direct sum of Hilbert space operators relatively to the same spectral characteristics of the coordinate operators are investigated. Then, the obtained results are supported by applications. The open problem posed by Demuth in 2015 and the works of Kittaneh and his researcher group in this area had an important effect on the formation of the subject discussed in this study.

Исследование возможностей использования инструмента имитационного моделирования AnyLogic в организации работы контрейлерного терминала

The article discusses theoretical issues of the functionality of using system modeling in the search for optimal conditions for developing technology in operating a piggyback terminal. The possibilities of using the AnyLogic simulation system for the parameters of a piggyback terminal, developed taking into account changing conditions that affect the indicators of interaction of internal elements, have been studied. A simulation model of a piggyback terminal has been developed, the simulated process is represented as a sequential cycle of events. More than a hundred experiments were carried out on the operation of blocks and elements of the logical algorithm for the model. An analysis of the functioning processes of the piggyback terminal has been carried out, taking into account the data declared for the study. The conclusions are formulated that the proposed simulation model of a piggyback terminal is focused on large-scale processing of incoming and outgoing cargo flows in piggybacks. This model allows you to analyze the implemented processes of predicted technological operations. The proposed model provides the ability to study processes as they change thanks to the resource of conducting an unlimited number of experiments and comparing the system indicators obtained in experiments for each block. This model opens up real ways to study and evaluate the objectivity of the expected financial costs when creating terminals.

Разработка математической модели отказоустойчивого преобразователя invsubbytes в полиномиальной системе классов вычетов

The article is devoted to the issue of improving the fault tolerance of the InvSubBytes procedure of SPN converters. Describes the possibility of applying a corrective code in a polynomial system of residue classes as a tool for detecting and eliminating the consequences of failures in the operation of replacement blocks.

On the pseudo semi-Browder essential spectra and application to 2 × 2 block operator matrices

On the pseudo semi-Browder essential spectra and application to 2 × 2 block operator matrices

The extent of commercial banks’ readiness to implement blockchain technology

This study aimed to find out the readiness of Jordanian commercial banks to implement blockchain technology. The population of this study consisted of thirteen Jordanian banks. The study targeted the employees of the higher departments represented by the general managers and their deputies, and the employees of the middle departments represented by the directors and heads of the departments of each of the finance, internal auditing, and information technology departments in Jordanian banks. The study used the survey method to collect data and the SPSS Statistics 20.0 program to process and analyze the data. The most important results of the study were the presence of a statistically significant impact of the banks’ readiness with its dimensions (administrative readiness, professional readiness, organizational readiness, and legislative readiness) in the blockchain technology with its dimensions (the use of blockchain technology, hashing, information, and time imprint). As for the most important recommendations, it crystallizes the need for Jordanian banks to carry out a continuous updating process on the data within the block, and to apply periodic tests on the block operations to verify that there are no gaps in the chain.

Spectral inclusion property for a class of block operator matrices

Spectral inclusion property for a class of block operator matrices

HYDRAULIC DESIGN AND SIMULATION OF DIFFERENT COMBINATIONS OF BLOCKS OPERATING IN TRICKLE IRRIGATION

There is little open-source software for trickle irrigation design and none of it is designed to simulate operating conditions on a specific hydraulic network already assembled in the field. Farmers employing trickle irrigation frequently need to change irrigation block operations over the years (parcel combinations), because of plant renovations in certain areas of the irrigated field or the adoption of precision irrigation. This work free software developed using Visual Basic® language that is able to simulate different block combinations of parcels, taking into consideration the pump parameters of flowrate, pressure, power requirements and efficiency and the main hydraulic network parameters of water speed, pressure and head loss. The software we developed was applied to a trickle irrigation system for citrus growing. The equations used to calculate head loss were Hazen-Williams and Darcy-Weisbach, and users could choose between these two equations depending on their application. The software worked efficiently for making the hydraulic calculations, providing simulations that graphically assisted users in choosing which combination of operation parcels (block combinations) and pump parameters (rotation speed and impeller diameter) for optimal operation of the irrigation system. The program ensured that the pressure along the irrigation network was compatible with the nominal operating pressure of the pipeline and safety valves.

Spectral analysis and domain truncation for Maxwell's equations

We analyse how the spectrum of the anisotropic Maxwell system with bounded conductivity σ on a Lipschitz domain Ω is approximated by domain truncation. First we prove a new non-convex enclosure for the spectrum of the Maxwell system, with weak assumptions on the geometry of Ω and none on the behaviour of the coefficients at infinity. We also establish a simple criterion for non-accumulation of eigenvalues at iR as well as resolvent estimates. For asymptotically constant coefficients, we describe the essential spectrum and show that spectral pollution may occur only in the essential numerical range We(L∞)⊂R of the quadratic pencil L∞(ω)=μ∞−1curl2−ω2ε∞, acting on divergence-free vector fields. Further, every isolated spectral point of the Maxwell system lying outside We(L∞) and outside the part of the essential spectrum on iR is approximated by spectral points of the Maxwell system on the truncated domains. Our analysis is based on two new abstract results on the (limiting) essential spectrum of polynomial pencils and triangular block operator matrices, which are of general interest. We believe our strategy of proof could be used to establish domain truncation spectral exactness for more general classes of non-self-adjoint differential operators and systems with non-constant coefficients.

Efficacy and safety of remimazolam for procedural sedation during ultrasound-guided transversus abdominis plane block and rectus sheath block in patients undergoing abdominal tumor surgery: a single-center randomized controlled trial

BackgroundTo explore the efficacy and safety of remimazolam for procedural sedation during ultrasound-guided nerve block administration in patients undergoing abdominal tumor surgery, in order to improve and optimize remimazolam use in procedural sedation and clinical anesthesia.MethodsThe enrolled patients were randomly divided into three groups: 50 patients in the remimazolam group (R group), 50 patients in the dexmedetomidine group (D group), and 50 patients in the midazolam group (M group). Before administering an ultrasound-guided nerve block, all patients received sufentanil AND remimazolam or midazolam or dexmedetomidine. Remimazolam 5 mg was administered intravenously in group R, dexmedetomidine 0.6 µg/kg was administered intravenously in group D, and midazolam 0.025 mg/kg was administered intravenously in group M. Sedation was evaluated by the Modified Observer’s Assessment of Alertness and Sedation scale.When the Modified Observer’s Alertness/Sedation (MOAA/S) score was ≤ 2, block operation was started. If the target sedation level was not reached, rescue sedatives of remimazolam 2.5 mg may be intravenously given in group R, dexmedetomidine 0.4 µg/kg be intravenously given in group D, 0.01 mg/kg midazolam may be intravenously given in Group M. Hemodynamic indicators (systolic and diastolic blood pressure, heart rate), pulse oxygen saturation, depth of anesthesia (Narcotrend), MOAA/S,and the incidences of hypoxemia, injection pain, bradycardia and requirement for rescue sedatives were monitored and recorded.ResultsCompared with the control groups (midazolam and dexmedetomidine groups), the Narcotrend index and MOAA/S decreased more in the remimazolam group (P < 0.01). Compared with the control groups, the incidence of hypoxemia and injection pain was slightly higher in the remimazolam group, but the difference was not statistically significant (P > 0.05). Compared with the dexmedetomidine group, the incidence of bradycardia was significantly lower in the remimazolam group.ConclusionRemimazolam can be used safely for procedural sedation during ultrasound-guided nerve block administration in patients undergoing abdominal tumor surgery. The sedation effect is better than that with either midazolam or dexmedetomidine, and sedation can be achieved quickly without obvious hemodynamic fluctuations. Remimazolam is associated with better heart rate stability, and slightly higher incidences of hypoxemia and injection pain than are midazolam and dexmedetomidine (no statistically significant difference). The higher incidence of hypoxemia with remimazolam may be related to enhanced sufentanil opioid analgesia, and the mechanism of injection pain with remimazolam must be studied further and clarified.Trial registrationThis study was approved by the Ethics Committee of Anhui Provincial Cancer Hospital (Ethical Review 2021, No. 23) and registered at https://www.chictr.org.cn (ChiCTR2000035388). The pre-registration time of this experiment is 09/08/2020, due to ethical committee of the hospital met irregularly,the ethical approval time is 21/06/2021. The recruitment of patients began after the ethical approval (21/06/2021) and registration update (06/07/2021).The study protocol followed the CONSORT guidelines. The study protocol was performed in the relevant guidelines.

E&amp;P Notes (December 2022)

E&amp;P Notes (December 2022)

On the closedness and self-adjointness of 3 × 3 operator matrices and application to a non-relativistic three-channel potential scattering model

In this paper, we are concerned with a 3 × 3 block operator matrices acting in a Banach or Hilbert space X 1 × X 2 × X 3 given by A 1 B 1 C 1 A 2 B 2 C 2 A 3 B 3 C 3 , where the linear entries are assumed to be unbounded. We study the closure as well as the self-adjointness in the case where the linear operators A 2 and A 3 are A 1 -bounded, B 1 and B 3 are B 2 -bounded and C 1 and C 2 are C 3 -bounded. These results are of importance to a non-relativistic three-channel potential scattering model.

Design of an Indirectly Coupled Filter Building Block for Modular Interleaved AC–DC Converters

This article presents the analysis and realization of a modular interconnected filter building block (FBB) operating under a single and multichannel (parallel three-phase converter blocks) configuration without loss of attenuation to any harmonic components. Emphasis is on the design of coupled inductor (CI) and boost inductor. In order to achieve a modular scheme with interleaved operation, indirect coupling between converters is realized using the secondary loop (SL)-based interconnection with inserted impedance. Here the “SL” serves as an additional pass for average grid side currents for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> channels. A building block type configuration has been proposed using this topology, inspired by the power electronics building block (PEBB) nature. The purpose of the loop is to interconnect the parallel converters in series using an arrangement of CIs. In addition, a boost inductor has been introduced in the SL to realize a power factor correction rectifier operation. The CI serves as the circulating current filter while reflecting channel currents toward the SL. To meet conducted electromagnetic interference (EMI) limits, a two-stage <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCLC</i> filter has been integrated with the FBB by introducing the point of common coupling (PCC) connection between two stages for filter size reduction. A design procedure is presented to meet power quality, circulating current, and EMI limits as per industry standards (EN-55011 and IEEE-519/1594). The proposed FBB has been characterized using 3L-NPC converters enabled with 1.2 kV Silicon Carbide based modules with comprehensive performance validation up to three channels in parallel with 15-kW power rating per channel.

Optimal Program-Read Schemes Toward Highly Reliable Open Block Operations in 3-D Charge-Trap NAND Flash Memory

3-D NAND flash memory with vertically stacked layers has been widely applied benefiting from its large capacities and high performances. Recently, a novel open block operation scheme was proposed for further improvements of the utilization efficiency in large capacity blocks. In this article, reliability issues of the open block operation in 3-D charge-trap (CT) NAND flash memory are studied by focusing on the high raw bit error rates (RBERs) in the last programmed word-line (WL), which is named as the edge WL (EWL). By systematical characterizations, it is concluded that high RBER in the EWL originates from lateral charge migration (LCM) due to the special structure of 3-D CT NAND flash. To suppress the RBER in EWL, we propose the extra read (ER) and extra program (EP) schemes to compensate for the charge loss from LCM. The experimental results show that the RBER of EWL can be reduced by an average of 59.8% and 86.5% after adopting ER and EP schemes, respectively. Furthermore, for the highly reliable open block, we design a targeted low-density parity-check (LDPC) operation process to enhance the correction capability. By using these two methods, experimental results show that the error correction capabilities of the LDPC hard decoding are increased by 1.92 and 4.76 times, respectively.

Generalized Drazin Invertibility of Operator Matrices

In this paper, we investigate the generalized Drazin invertibility of upper triangular operator matrices acting on Banach spaces. Among other things, we explicit the defect set with respect to the local spectral theory. Moreover, we exhibit some sufficient conditions which assure that the generalized Drazin spectrum of a 3 × 3 upper triangular block operator matrix is the union of its diagonal entries spectra.