bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interval observer design for nonlinear systems using simplified contraction theory
Authors: Singh Bhawana , Xiong Xiaogang , Dinh Thach Ngoc , Kamal Shyam , Ghosh Sandip 
Published: April 2022

AbstractIn this work, vector framework based contraction theory to design interval observers for a class of nonlinear systems having disturbances, inputs and outputs is exploited. The main feature is that it does not require the formulation of error dynamics to show the convergence properties and need not require the construction of a Lyapunov candidate function without any idea of the structure of the function. Specifically, it performs the convergence analysis through a comparison system which has specified properties. Furthermore, this theory is exploited to design dynamic output feedback control through the obtained state bounds from the constructed interval observer and the system outputs, to make the interval observer to be globally asymptotically stable. Examples with simulation outcomes are provided to validate the theoretical results.
Bayesian adaptive direction detector in sample‐starved environment
Authors: Sha Minghui , Mao Erke , Meng Fei 
Published: April 2022

AbstractHere, the problem of direction detection in disturbance with unknown covariance matrix is considered. The case that the number of the training data is too small to form an effective estimate for the unknown covariance matrix is focused upon. To solve the problem, the Bayesian framework is resorted to. Precisely, the unknown covariance matrix is assumed to be ruled by an inverse Wishart distribution. Then the problem is solved by the detector design criterion of generalized likelihood ratio test. Numerical examples indicate that the proposed detector can effectively detect the target, and provide higher probability of detection than the existing detectors even when sufficient training data are available.
Multi‐level refined power system operation mode analysis: A data‐driven approach
Authors: Li Yunyi , Bai Xiaoqing , Meng Jianling , Zheng Liqin 
Published: April 2022

AbstractThe high renewable penetration will cause the power system operation mode (PSOM) to change frequently. At present, the selection of PSOM mainly depends on the experience of relevant staff. However, selecting PSOM based on experience is difficult to comprehensively and elaborately analyze the possible PSOMs within a dispatching cycle, which inevitably invites troubles to the power system planning and dispatching. In this paper, a data‐driven analysis method is proposed, which integrates the techniques of preprocessing, dimensionality reduction, clustering, and data visualization of high‐dimensional data sets of power system operation. Simultaneously, qualitative and quantitative methods are used to analyze, evaluate the PSOM and their development laws. Finally, to verify the effectiveness of the proposed multi‐level refinement extraction method of PSOM, the normal power system operation mode (NPSOM), transition power system operation mode (TPSOM), extreme power system operation mode (EPSOM) are obtained and analyzed according to the real operation data of the urban power system. The abundant analysis results show that the proposed fine‐grained extraction method of PSOM is compelling, facilitating the power grid enterprise operation and planning.
Post‐fault operation strategy for single open‐phase fault in three‐phase induction motor drives
Authors: Abbasi Hadi , Ghanbari Mahmood , Ebrahimi Reza , Jannati Mohammad 
Published: April 2022

AbstractSingle open‐phase fault (SOPF) in three‐phase induction motor (TPIM) drives leads to undesired performances and in some cases shutdown of the drive system. This research proposes a post‐fault operation strategy based on direct rotor field‐oriented control (RFOC) technique for wye‐connected TPIM drives during SOPF. In the proposed control system, symmetrical and asymmetrical transformation matrices are utilized for stator voltage and current variables, respectively. In addition, an extended Kalman filter (EKF) is used for the rotor flux estimation, filtration of stator currents, and obtaining their time derivatives. The performance of the introduced technique including steady and transient states during different reference speeds is experimentally validated for a wye‐connected TPIM drive considering SOPF. Additionally, the performance of the proposed strategy is experimentally compared with conventional RFOC strategies.
Post-laminectomy Dorsal Cord Migration Resulting in Immediate Neurologic Deterioration during Ventral Meningioma Resection: Proposed Mechanism of Injury and Prevention Technique
Authors: Harel Ran , Kimchi Gil , Perry Avital , Korn Akiva , Knoller Nachshon 
Published: April 2022

Abstract
Background Ventral thoracic meningiomas may pose a technical challenge owing to a limited surgical corridor and the presence of long-standing ventral cord compression. Unopposed dorsal spinal cord migration may occur following a laminectomy resulting in immediate neurologic injury. We discuss the possible mechanism underlying such a phenomenon, suggesting alternative approach to prevent neurologic injury.
Methods Two patients operated on for ventral thoracic meningioma and sustained neurologic compromise were retrospectively evaluated. Image editing software was used for 3D modeling to simulate the possible underlying mechanism of injury. Cases where ventral thoracic meningiomas were approached via unilateral hemilaminectomy, performed in 2020, were retrospectively analyzed and compared with the laminectomy approach cohort.
Results Two patients sustained postoperative neurologic function decline following resection of ventral thoracic meningioma via the laminectomy approach. Both exhibited permanent abolishment of transcranial motor evoked potentials (MEPs) following laminectomy. Based on the extrapolated 3D models for these two cases, dorsal cord migration was postulated as the cause for the acute neurologic compromise.
Conclusion Laminectomy for resection of thoracic ventral meningioma may lead in some cases to dorsal cord migration resulting in grave neurologic deterioration. Unilateral approach to these tumors restricts the dorsal migration and may mitigate neurologic outcomes.
Meningeal Metastasis Causing Chronic Subdural Hematoma in a Cancer Patient with Bilateral Papilledema and Suspected Cerebral Venous Thrombosis: A Case Report
Authors: Pangratz-Daller Cornelia , Grimm Jochen , Pfaff Johannes A.R. , Kraus Theo F.J. , Sotlar Karl , Rahman Al-Schameri Abdul , Kral Michael , Griessenauer Christoph J. , Schwartz Christoph 
Published: April 2022

AbstractMeningeal metastasis has been reported as a very rare cause of chronic subdural hematoma (CSH). Here, we report a female patient who had undergone initial burr hole drainage of a CSH at an outside hospital. Postoperatively, the patient additionally suffered from visual impairment due to bilateral papilledema and the patient was eventually transferred to our neurosurgical department for additional treatment. A craniotomy was performed and due to intraoperative suspicious findings, histopathologic samples were obtained that revealed a metastasis of thus far undiagnosed triple negative breast cancer. Furthermore, the patient was suspected to have a partial cerebral venous thrombosis (CVT). Our case report addresses this extremely rare clinical constellation. We provide a detailed overview on our patient's clinical and radiologic course, and discuss the potential association of CSH with meningeal metastasis and bilateral papilledema.
The Role of Diskectomy in Reducing Infectious Complications after Surgery for Lumbar Spondylodiscitis
Authors: Schatlo Bawarjan , Rohde Veit , Abboud Tammam , Janssen Insa , Melich Patrick , Meyer Bernhard , Shiban Ehab 
Published: April 2022

Abstract
Background Surgery for pyogenic Spondylodiscitis as an adjunct to antibiotic therapy is an established treatment. However, the technique and extent of surgical debridement remains a matter of debate. Some propagate diskectomy in all cases. Others maintain that stand-alone instrumentation is sufficient.
Methods We reviewed charts of patients who underwent instrumentation for pyogenic Spondylodiscitis with a minimum follow-up of 1 year. Patients were stratified according to whether they underwent diskectomy plus instrumentation or posterior instrumentation alone. Outcome measures included the need for surgical revision due to recurrent epidural intraspinal infection, wound revision, and construct failure.
Results In all, 257 patients who underwent surgery for pyogenic Spondylodiscitis were identified. Diskectomy and interbody procedure (group A) was performed in 102 patients, while 155 patients underwent instrumentation surgery for Spondylodiscitis without intradiskal debridement (group B). The mean age was 67 ± 12 years, and 102 patients (39.7%) were females. No significant differences were found in the need for epidural abscess recurrence therapy (group A [2.0%] and 5 cases in group B [3%; p = 0.83]) and construct failure (p = 0.575). The need for wound revisions showed a tendency toward higher rates in the posterior instrumentation–only group, which failed to reach significance (p = 0.078).
Conclusions Overall, intraspinal relapse of surgically treated pyogenic diskitis was low in our retrospective series. The choice of surgical technique was not associated with a significant difference. However, a somewhat higher rate of wound infections requiring revision in the group where no diskectomy was performed has to be weighed against a longer duration of surgery in an already ill patient population.
Evaluation of High-Risk Human Papillomavirus Testing in Women with Atypical Squamous Cells of Undetermined Significance to Detect Cervical Intraepithelial Neoplasia
Authors: Kawase Rieko , Suzuki Shunji 
Published: April 2022

Introduction We retrospectively examined the changes in the management and outcomes of the cases with atypical squamous cells of undetermined significance (ASC-US) according to the Bethesda system (TBS).
Materials and Methods Between May 2009 and December 2018, 432 cases with ASC-US were retrospectively examined for the implementation of high-risk human papillomavirus (hrHPV) testing and/or cervical biopsy and clinical courses.
Results The hrHPV testing was performed in 277 cases (64.1%). Of these, there were 80 with positive hrHPV (28.9%). Of the 80 cases, cervical biopsy was performed in 71 (88.9%) cases based on the finding of colposcopy. Cervical intraepithelial neoplasia (CIN) was diagnosed in 55 cases (77.4%). The sensitivity, specificity, positive predictive value, and negative predictive value of CIN diagnosis by hrHPV testing in cases of ASC-US were 72.5, 95.0, 88.7, and 86.3%, respectively (p < 0.01).
Conclusion The conducting of hrHPV test on women who were evaluated as ASC-US according to TBS affirmed its clinical usefulness.
A Case Report of Early-Onset Frey's Syndrome in an Infant
Authors: Pavlovic Momcilo 
Published: April 2022

AbstractThe appearance of flushing in the territory of the auriculotemporal nerve after ingestion of foods with a sweet, salty, or sour flavor could suggest Frey's syndrome, especially if the infant has a history of obstetric trauma. This rare and benign condition requires no diagnostic exploration or treatment. A 3-month-old male infant presented with facial flushing since he was 6 weeks' old. Episodes of flushing were stereotypical, over the zone innervated by the left auriculotemporal nerve. They started 10 to 15 seconds after the beginning of the feeding and disappeared after 15 to 20 minutes. At the time of the onset of facial erythema, the infant was exclusively bottle feeding. Diagnosis of Frey's syndrome was made on historical and clinical grounds, and no further testing was needed. Flushing gradually started to fade at the age of 5 months and completely disappeared after 8 months. Introducing solid food did not cause any deterioration of facial erythema. Early recognition of Frey's syndrome is important to avoid unnecessary investigation and therapy. On the other hand, our reported case warns that Frey's syndrome may occur in very early infancy without ingestion of solid food.
Structural basis of protein substrate processing by human mitochondrial high-temperature requirement A2 protease
Authors: Toyama Yuki , Harkness Robert W. , Kay Lewis E. 
Published: April 2022

Significance
Protein aggregates are often toxic, leading to impaired cellular activities and disease. The human HtrA2 trimeric enzyme cleaves such aggregates, and mutations in HtrA2 are causative for various neurodegenerative disorders, such as Parkinson’s disease and essential tremor. The mechanism by which cleavage occurs has been studied using small peptides, but little information is available as to how HtrA2 protects cells from the pathologic effects of aggregation involving protein molecules that can form well-folded structures. Using solution NMR spectroscopy, we investigated the structural dynamics of the interaction between HtrA2 and a model protein substrate, demonstrating that HtrA2 preferentially binds to an unfolded substrate ensemble and providing insights into how HtrA2 function is regulated.
Fabrication and flow rate characterization of a DRIE process based valveless piezoelectric micropump
Authors: Şimşek Sevda , Vahid Ebrahimpour Ahmadi , Çelik Süleyman , Sayar Ersin , Koşar Ali 
Published: April 2022

AbstractMicropumps have become one of the major research topics in the field of microfluidics. Different actuators have been used in active micropumps including piezoelectric ones, which convert electrical energy to mechanical energy. In this study, a piezoelectric disc was designed as an actuator and was integrated into a fabricated piezoelectric micropump. Unlike wet etching methods, which is generally used to etch layers of relatively high thickness in the silicon wafer, dry etching was used in this study. Aluminum was used as a mask material during the fabrications-steps, and the fabrication process was shortened with the use of the masking steps. The etching process of the slot, in which the piezoelectric disc was placed, and etching of the inlet/outlet channels were performed simultaneously. Thus, the processing time was significantly shortened. The fabrication of this silicon-based valveless micropump was accomplished by using the DRIE (deep reaction-ion etching) technique, which provided controlled etching. Experiments were conducted on the fabricated micropump with the use of the bulk micromachining technology to deliver the desired pumping action. The leakage and the air entrapment between the consecutive micropump structural layers were satisfactorily eliminated. This micropump is capable of delivering a promising flow rate of 52 (µl min−1) for deionized water, which corresponds to a 150 [Hz] square wave type and a peak-to-peak voltage of 60 (V)Vp-p. No moving mechanical valves were included so that the risks of clogging, reduced performance, and reduced reliability due to wear and fatigue were minimized. Not only gases and liquids but also fluids containing particles could be used as the working fluid for this micropump. The piezoelectric micropump design was optimized to achieve a high time-averaged flow rate (>50 (µl min−1)) with a relatively low excitation voltage (<100 (V)Vp-p) as opposed to the use of a high excitation voltage.
On the importance of electron–electron and electron–phonon scatterings and energy renormalizations during carrier relaxation in monolayer transition-metal dichalcogenides
Authors: Hader Jörg , Neuhaus Josefine , Moloney Jerome V , Koch Stephan W 
Published: April 2022

Abstract
An ab initio based fully microscopic many-body approach is used to study the carrier relaxation dynamics in monolayer transition-metal dichalcogenides. Bandstructures and wavefunctions as well as phonon energies and coupling matrix elements are calculated using density functional theory. The resulting dipole and Coulomb matrix elements are implemented in the Dirac–Bloch equations to calculate carrier–carrier and carrier–phonon scatterings throughout the whole Brillouin zone (BZ). It is shown that carrier scatterings lead to a relaxation into hot quasi-Fermi distributions on a single femtosecond timescale. Carrier cool down and inter-valley transitions are mediated by phonon scatterings on a picosecond timescale. Strong, density-dependent energy renormalizations are shown to be valley-dependent. For MoTe2, MoSe2 and MoS2 the change of energies with occupation is found to be about 50% stronger in the Σ and Λ side valleys than in the K and K′ valleys. However, for realistic carrier densities, the materials always maintain their direct bandgap at the K points of the BZ.
Half-topological state in magnetic topological insulators
Authors: Tran Minh-Tien , Tran Thanh-Mai Thi 
Published: April 2022

Abstract
We predict a novel topological state, half-topological state, in magnetic topological insulators. The topological state is characterized by different topologies of electrons with different spin orientations, i.e., electrons with one spin orientation occupy a nontrivial topological insulating state, while electrons with opposite orientation occupy another insulating state with trivial topology. We demonstrate the occurrence of the half-topological state in magnetic topological insulators by employing a minimal model. The minimal model is a combination of the spinful Haldane and the double-exchange models. The double-exchange processes maintain a spontaneous magnetic ordering, while the next-nearest-neighbor hopping in the Haldane model gives rise to a nontrivial topological insulator. The minimal model is studied by applying the dynamical mean field theory. It is found that the long-range antiferromagnetic ordering drives the system from either topological or topologically trivial antiferromagnetic insulator to the half-topological state, and finally to topologically trivial antiferromagnetic insulator. The equations for the topological phase transitions are also explicitly derived.
Informative singular value decomposition and its application in fault detection of planetary gearbox
Authors: Shen Zhaoyang , Shi Zhanqun , Shen Guoji , Zhen Dong , Gu Fengshou , Ball Andrew 
Published: April 2022

Abstract
The fault features of planetary gearboxes are modulated complexly and are submerged by other signal components, for its vibration signal has the characteristics of multi-source and multi transmission path. A fault detection method of planetary gearboxes based on informative singular value decomposition and envelope spectrum analysis (ISVD-ESA) is proposed in this paper. In this method, the advantage of blind source separation of singular value decomposition (SVD) method is combined with the ability of negentropy and cyclic autocorrelation (CA) in non-Gaussian characteristics recognition. The fast SVD is firstly performed to decompose the vibration signal into a series of singular value decomposition component signals (SVCSs). Secondly, the detector of negentropy combined with CA is applied to estimate the fault informativeness of each SVCS. The SVCSs are amplified by the fault informativeness and reconstructed to the out signal of ISVD. Finally, the fault features can be extracted by the ESA from the output signal of ISVD. The performance of the proposed method is verified by simulation and experimental studies. Results show that the proposed ISVD-ESA strategy can enhance the weak features of multi-modulation and accurately extract the faults of tooth tip pitting and misalignment of sun gear of the planetary gearbox.
DC and optical signatures of the reconstructed Fermi surface for electrons with parabolic band
Authors: Rukelj Zoran , Radić Danko 
Published: April 2022

Abstract
We study the main intra-band and inter-band transport properties at zero temperature of free electron-like system undergoing a topological reconstruction of the Fermi surface for the two-dimensional and three-dimensional case. The calculated intra-band properties include the single-particle density of states, the total and the effective concentrations of electrons and the thermopower. As for the inter-band case, the real part of the conductivity has been calculated within the vanishing inter-band relaxation approximation as a function of the incident photon energy. Within this approach, it is shown that the optical conductivity has a nonvanishing component parallel to the reconstruction wave vector and the shape which depends on the value of the Fermi energy. Each dimensionality has its particular features in the transport quantities presented in the paper, which are discussed and compared with those in the free electron scenario. Finally, we identify the signature of the topological reconstruction of the Fermi surface in the intra-band and inter-band transport functions.
Phase synchronization versus modulational instability for zonal flow generation and pattern formation
Authors: Yi Sumin , Jhang Hogun , Kim S.S. , Kwon Jae-Min 
Published: April 2022

Abstract
From global gyrokinetic simulations of toroidal ion temperature gradient-driven (ITG) turbulence, we identify two distinguished regimes where zonal flow generation and its radial pattern formation is governed by either phases or amplitudes of the turbulence spectrum. When the unstable region is wider than the correlation length of ITG modes, the zonal flow structure changes in a turbulence time scale. We newly uncover that the radial phases of ITG modes determine the evolution of the zonal flow structure. Synchronization of mode phases induced by the global zonal flow drives a fine-scale zonal flow pattern. With a narrow unstable region comparable to the mode correlation length, the phase effect almost vanishes. In this regime, we recover that the modulational instability promptly amplifies a coherent zonal flow, leading to a lower turbulence saturation level. This finding explains the reduction of turbulent transport at a narrow width of the strong gradient region, which has been attributed to the system size effects in ion-scale gyrokinetic turbulence.
Compaction history based on porosity, pressure and temperature relation in Central Luconia province, offshore Sarawak
Authors: Refael  , Jamaludin Siti Nur Fathiyah , Latiff Abdul Halim Abdul 
Published: April 2022

Abstract
This study investigates the role of porosity in relation to temperature and pressure within Miocene-Pliocene sediments in Central Luconia province. The main objective is to understand the effect on porosity loss within Miocene-Pliocene sediments as part of the compaction of the sediments through time. The methodology involves seismic interpretation of 2D seismic lines and analysis of four wells over the central complex in Central Luconia province. Thick sedimentation was found within the clastic sediments of Cycle VI, indicating major clastic influx from the deltas and onshore of Sarawak during Pliocene. These clastic sediments had become a major source of weight in the offshore basin, inducing compaction within the older formations. Porosity distributions based on the wells showed that Cycle VI had the highest porosity in LH1 well with 33.77% porosity, while porosity within Cycle IV & V limestone showed an average porosity of 22% in all wells. Porosities within Cycle III and Cycle II were observed to be average of 16%. The porosity within the reservoir rock was reduced as the depth increased. This porosity reduction was relatively due to the compaction of the sediments, linked with the changes of pressure and temperature indicated by several evidences found in each well. Overpressure zone affects irregularity of porosity reduction with depth, whereas high temperature promotes diagenetic reaction that causes sudden porosity loss. Nevertheless, a sudden increase in porosity was also observed at the top of Cycle IV & V limestone due to a major drop in the sea level during the Early Late Miocene, which had encouraged the karstification process, inducing secondary porosity. This study has proved that compaction within Miocene-Pliocene sediments is not only related to the loss in porosity, but it involves changes in pressure and temperature regime of sediments and is highly dependent on the natural changes of sea level.