Phenomenon Of Loss Research Articles

Stability of nonlinear impulsive systems with non-uniformly distributed packet loss

This study focuses mainly on the stability of a class of nonlinear systems with impulsive disturbance. In particular, we consider the possible non-uniformly distributed packet loss phenomenon in the controller-to-actuator channel. This packet loss is described by a characterization scenario in the average sense, known as the average packet loss interval (APLI). In this scenario, an average allocation strategy between the number of impulsive sampling intervals and the length of packet loss intervals is established. This implies that the limitations on the proportion or the upper bound of packet loss intervals can be relaxed. A sampled-data control is put forward based on impulsive disturbance, which not only brings better control performance but also reduces conservatism. In view of the Halanay inequality, the number of subsystem switchings caused by packet loss is allowed to be arbitrary. Based on the elastic constraint relationships established between system parameters and APLI, a series of conditions guaranteeing the globally uniformly exponential stability (GUES) are provided. Further, the admissible packet loss intervals can be estimated on an average basis by solving an algebraic inequality. Finally, a numerical example is discussed to demonstrate the validity of our study.

Genetic analysis of potential biomarkers and therapeutic targets in age-related hearing loss

Age-related hearing loss (ARHL) or presbycusis is the phenomenon of hearing loss due to the aging of auditory organs with age. It seriously affects the cognitive function and quality of life of the elderly. This study is based on comprehensive bioinformatic and machine learning methods to identify the critical genes of ARHL and explore its therapy targets and pathological mechanisms. The ARHL and normal samples were from GSE49543 datasets of the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was applied to obtain significant modules. The Limma R-package was used to identify differentially expressed genes (DEGs). The 15 common genes of the practical module and DEGs were screened. Functional enrichment analysis suggested that these genes were mainly associated with inflammation, immune response, and infection. Cytoscape software created the protein-protein interaction (PPI) layouts and cytoHubba, support vector machine-recursive feature elimination (SVM-RFE), and random forests (RF) algorithms screened hub genes. After validating the hub gene expressions in GSE6045 and GSE154833 datasets, Clec4n, Mpeg1, and Fcgr3 are highly expressed in ARHL and have higher diagnostic efficacy for ARHL, so they were identified as hub genes. In conclusion, Clec4n, Mpeg1, and Fcgr3 play essential roles in developing ARHL, and they might become vital targets in ARHL diagnosis and anti-inflammatory therapy.

COVID-19 SCHOOL CLOSURES IMPACTS ON PRIMARY SCHOOL STUDENTS� MATHEMATICS COMPETENCE

School closures and home learning policy to prevent the spread of COVID-19 in Indonesia raised concerns about learning loss. This research was focused on examining the potential for learning loss in terms of the mathematical competence of year-3 indigenous primary school students in Indonesia due to school closures during the pandemic. This qualitative research with a phenomenological approach involved 8 year-3 students who had been studying from home for the last 1.5 years or so. Data collection was carried out using mathematical diagnostic tests and interviews. Results from this study revealed the phenomenon of learning loss in terms of the mathematical competence among the students, where the mastery of prior mathematics knowledge and skills required for grade 3 were not mastered yet. Also, their mathematical competences were below the competency standard in the curriculum for grade 3 primary school in Indonesia. The significancy of this study emphasized that the phenomenon of learning loss that occurred in primary school students during and even after the COVID-19 pandemic should be a serious concern for all parties and stakeholders. Hence, some solutions and quick steps that need to be taken to mitigate the long-term impacts of learning loss are also included in this article.

Modeling and Optimization of High-Capacity Experimental Reclaimers to Minimize the Seed and Lint Loss during Roller Ginning of Upland and Pima Cotton

In the present study, two high-capacity experimental roller gin reclaimers, (a) a modified 3-saw cylinder stick machine (three-saw) and (b) a modified 2-saw cylinder gin stand feeder (700), were optimized with respect to reclaimer saw cylinder speed and carryover/seed ratio to minimize the seed and lint loss for both Pima and Upland cotton varieties and were compared to a conventional roller gin reclaimer operated by the ginning industry under standard conditions. Developed regression models adequately described the seed and lint loss phenomena during the reclaiming process. Surface plots indicated that the reclaimer saw cylinder speed and carryover/seed ratio impacted the seed and lint loss for both the 3-saw and 700 reclaimers. Under optimized conditions, the 700 reclaimer resulted in lower lint and seed loss compared to the 3-saw reclaimer when using Upland cotton. In the case of Pima cotton, under optimized conditions, the 3-saw reclaimer had 38% lower lint loss and 24% higher seed loss compared to the 700 reclaimer. The regression equations of both 3-saw and 700 reclaimers were further used to optimize the reclaimers in parallel arrangement to minimize the seed and lint loss. With Upland cotton, the economic loss was about 2.5 times greater with the conventional reclaimer compared to the 3-saw and 700 reclaimers ($15.97/bale loss for the conventional, $8.63 for the 3-saw, and $6.44 for the 700 reclaimers). With Pima cotton, the conventional reclaimer resulted in a lower economic loss ($3.44/bale) compared to the 700 reclaimer which had a loss of about $3.59/bale.

Comprehensive analytical model of energy and exergy performance of the thermal energy storage

Determining the performance of heat storage units is essential to reliably determine the capability of entire energy storage systems, as several energy loss and dissipation phenomena can significantly degrade its final efficiency. Previous scientific works has not focused on the detailed treatment of the heat storage tank and its impact on the functioning of other system components. The work emphasizes the presentation of a in-house numerical model of Thermal Energy Storage filled with rock material. The comprehensive numerical model has been presented that also takes into account the variable operating parameters of the compressor and air expander. The multivariate nature of the model used makes it possible to estimate the influence of individual factors on the final efficiency of the system. The calculations made it possible to determine the potential of a system with a capacity of 175 MWh using post-mining shafts. The long-term energy efficiency of the system was 57.47%, with a heat storage energy efficiency of 91.96% and an exergy efficiency of 82.93%. Implementation of the model has the potential to provide more accurate estimations of the potential of proposed energy systems using heat storage.

Robust Fusion Kalman Estimator of the Multi-Sensor Descriptor System with Multiple Types of Noises and Packet Loss.

Under the influence of multiple types of noises, missing measurement, one-step measurement delay and packet loss, the robust Kalman estimation problem is studied for the multi-sensor descriptor system (MSDS) in this paper. Moreover, the established MSDS model describes uncertain-variance noises, multiplicative noises, time delay and packet loss phenomena. Different types of noises and packet loss make it more difficult to build the estimators of MSDS. Firstly, MSDS is transformed to the new system model by applying the singular value decomposition (SVD) method, augmented state and fictitious noise approach. Furthermore, the robust Kalman estimator is constructed for the newly deduced augmented system based on the min-max robust estimation principle and Kalman filter theory. In addition, the given estimator consists of four parts, which are the usual Kalman filter, predictor, smoother and white noise deconvolution estimator. Then, the robust fusion Kalman estimator is obtained for MSDS according to the relation of augmented state and the original system state. Simultaneously, the robustness is demonstrated for the actual Kalman estimator of MSDS by using the mathematical induction method and Lyapunov's equation. Furthermore, the error variance of the obtained Kalman estimator is guaranteed to the upper bound for all admissible uncertain noise variance. Finally, the simulation example of a circuit system is examined to illustrate the performance and effectiveness of the robust estimators.

Geothermal effects on CO[formula omitted] dissolution kinetics in brine: A non-dimensional model for underground storage in salt caverns

Understanding the dissolution kinetics of CO2 in brine is important for efficient management of cycled CO2 in underground salt caverns. The kinetics is strongly influenced by natural convection, which is caused by density changes related to the concentration of dissolved gas as well as thermal changes driven by CO2 cycling and the effects of the geothermal gradient. Based on a novel non-dimensional model that couples cavern thermodynamics with the dissolution mechanisms, this study investigates how the natural convection related to mass and thermal changes impacts dissolution kinetics. The numerical model is validated using laboratory measurements, and thereupon upscaled to typical dimensions of a salt cavern. Although our simulations show that the total dissolved mass is relatively minor compared to the initial stored mass/cycled mass, it is nevertheless important to quantify other loss phenomena, particularly gas permeation into the host rock salt. The developed model can also be adapted easily to study the kinetics of dissolution of other gases, such as hydrogen and methane.

Mouse models of cerebral injury and cognitive impairment in hypertension.

Hypertension is a major risk factor for dementia, including both vascular and neurodegenerative etiologies. With the original aim of studying the effect of blood pressure elevation on canonical target organs of hypertension as the heart, the vasculature or the kidneys, several experimental models of hypertension have sprouted during the years. With the more recent interest of understanding the cerebral injury burden caused by hypertension, it is worth understanding how the main models of hypertension or localized cerebral hypertension stand in the field of hypertension-induced cerebral injury and cognitive impairment. With this review we will report main genetic, pharmacological and surgical models of cognitive impairment induced by hypertension, summarizing how each specific category and model can improve our understanding of the complex phenomenon of cognitive loss of vascular etiology.

Mixed [formula omitted] control for discrete-time periodic Markov jump systems with quantization effects and packet loss compensation

This article concentrates on the issue of the mixed H2/H∞ state feedback control for discrete-time periodic Markov jump systems with quantization effects and packet loss compensation. Considering that the communication channel is limited, the state signals need to be quantized by a logarithmic quantizer with mode-dependent property before communication. When the quantized state is passed to the controller, the stochastic packet loss phenomenon may occur, which follows Bernoulli stochastic distribution. Therefore, a new packet loss compensation strategy is put forward, which adopts the single exponential smoothing method to predict the lost data. Additionally, considering that the system modes are not always fully available, a periodic controller with partially mode-dependent property is devised to ensure that the system is stochastically stable with the predefined mixed H2/H∞ performance. Then, the sufficient conditions for the existence of periodic controller are established by constructing a periodic Lyapunov function, which is mode-dependent. Ultimately, a practical example of a boost converter is presented to verify the validity of the proposed approach.

Iatrogenic inner ear dehiscence associated with lateral skull base surgery: a systematic analysis of drilling injuries and their causal factors.

Drilling injuries of the inner ear are an underreported complication of lateral skull base (LSB) surgery. Inner ear breaches can cause hearing loss, vestibular dysfunction, and third window phenomenon. This study aims to elucidate primary factors causing iatrogenic inner ear dehiscences (IED) in 9 patients who presented to a tertiary care center with postoperative symptoms of IED following LSB surgery for vestibular schwannoma, endolymphatic sac tumor, Meniere's disease, paraganglioma jugulare, and vagal schwannoma. Utilizing 3D Slicer image processing software, geometric and volumetric analysis was applied to both preoperative and postoperative imaging to identify causal factors iatrogenic inner ear breaches. Segmentation analyses, craniotomy analyses, and drilling trajectory analyses were performed. Cases of retrosigmoid approaches for vestibular schwannoma resection were compared to matched controls. Excessive lateral drilling and breach of a single inner ear structure occurred in 3 cases undergoing transjugular (n=2) and transmastoid (n=1) approaches. Inadequate drilling trajectory breaching ≥1 inner ear structure occurred in 6 cases undergoing retrosigmoid (n=4), transmastoid (n=1), and middle cranial fossa approaches (n=1). In retrosigmoid approaches the 2-cm visualization window and craniotomy limits did not provide drilling angles to the entire tumor without causing IED in comparison to matched controls. Inappropriate drill depth, errant lateral drilling, inadequate drill trajectory, or a combination of these led to iatrogenic IED. Image-based segmentation, individualized 3D anatomical model generation, and geometric and volumetric analyses can optimize operative plans and possibly reduce inner ear breaches from lateral skull base surgery.

Leader-Follower Quasi-Consensus of Multi-Agent Systems with Packet Loss Using Event-Triggered Impulsive Control

This paper focuses on the leader–follower quasi-consensus problem of multi-agent systems, considering the practical communication scenarios which involve packet loss. The phenomenon of packet loss is described in terms of the packet loss rate. A novel hybrid event-triggered impulsive control strategy is proposed, the Lyapunov stability theory is employed to derive sufficient conditions for realizing the leader–follower quasi-consensus, and the exclusion of Zeno behavior is demonstrated. Finally, a numerical simulation example is provided to verify the effectiveness of the proposed approach. The simulation results indicate that the packet loss rate is closely related to the control gain and the maximum triggered interval, specifically because as the packet loss rate increases, the trigger frequency also increases.

Route “Roads of Memory”: Resource of the Commemorative Practice on the Places of Hostilities on the Territory of Russia and Belarus (1941–1945)

This article is devoted to the description of the implementation of the route “Roads of Memory” as a format of historical “immersion” in the research material that contributes to the reconstruction of social memory about the events of the Great Patriotic War, the phenomenon of human losses during the War, the formation of the meaning of this phenomenon and the veneration of humanistic value. This commemorative practice turned out to be extremely understandable and successful in the format of research objectives of the archival search team. In July 2019, a group of students with a professor, in connection with the 75th anniversary of the liberation of the Byelorussian SSR territory from the invaders, went to the Republic of Belarus in order to visit the brotherly burials where the remains of Siberians rest. The commemoration was called “Roads of Memory” and covered the route from Novosibirsk through Moscow to Smolensk – Roslavl – Minsk – Vitebsk. The participants visited the burial sites of Red Army soldiers who died in battles during the Great Patriotic War or in concentration camps. The study used a set of complementary methods that contribute both to the effectiveness of the search and to the professional promotion of the participants of the archival search team. The narration of the events described by the route “Roads of Memory” is a combination of a diary essay and storytelling, in the tradition of the narrative approach.

Cycle performance analysis of lead–carbon electrode under high-load conditions for automotive battery applications

This work studies the cycle performance of lead-carbon (LC) negative electrode and reference lead negative electrode via a 50% depth-of-discharge (50%DoD) cycle test for automotive applications. The cycle performance results reveal a greater cycle number for the LC cell. The discharge voltages and the growth of peaks at high DoD in differential voltage analysis exhibit alleviated concentration loss phenomenon for the LC cell. Sulfation is confirmed for both kinds of electrodes via X-ray diffraction. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) reveal better preserved inner morphology and electrochemical reactivity for the cycled LC electrode, respectively, while SEM and energy-dispersive X-ray spectroscopy (EDS) detect PbSO4 existence on the carbon layer. EDS on the electrode cross-section confirms PbSO4 deposition on the carbon layer and less sulfation in the LC electrode interior. CV results indicate effects resulting from PbSO4 deposition on the carbon layer through decreasing capacitance and suppressed hydrogen gassing. Conclusively, the carbon layer of the LC electrode creates exterior sharing space for PbSO4 precipitation, causing lower sulfation of the inner electrode interface. Thus, the present study establishes the electrode degradation mode and cycle performance of the lead-carbon electrode in this cycling profile.

A general equation for estimation of time-dependent prestress losses in prestressed concrete members

Due to the inherent nature of concrete shrinkage, creep and relaxation of prestressing strands, the prestress in prestressed concrete structures decreases continuously with time, i.e., there is an apparent time-dependent prestress loss phenomenon for prestressed concrete structures. Therefore, it is an important issue for the estimation of time-dependent prestress losses in the design of prestressed concrete structures. Many current design codes provide relevant equations for the evaluation of prestress losses. For the prestressed concrete structure, in addition to the prestressing strands, a great amount of ordinary reinforcing steel is configured to enhance its load-carrying capacity. It is generally considered that no stress relaxation occurs for ordinary reinforcing steel due to its lower stress. However, the presence of ordinary reinforcing steel affects the stress distribution in the structure and thus has an obvious impact on the prestress losses, which is not considered in the prediction equations in most current codes for the design of concrete structures up to date. In this study, based on the cross-sectional analysis of prestressed concrete members that combines the age-adjusted effective modulus method of concrete creep analysis, a general equation for estimation of the time-dependent prestress losses in prestressed concrete members considering the influence of ordinary reinforcing steel is derived and simplified. When the influence of ordinary reinforcing steel is ignored, i.e., the percentage of ordinary reinforcing steel is taken as zero, the proposed equation reduces to those in Eurocode EN 1992-1-1:2004 and AASHTO LRFD 2020. In the end, an example of a T-shaped prestressed concrete girder is provided to show the application of the proposed equation for the evaluation of time-dependent prestress losses and the error resulting from the simplification of the equation. The results show that ordinary reinforcing steel has a significant effect on the time-dependent prestress losses in prestressed concrete members for the commonly used percentage of ordinary reinforcing steel, and the error arising from the simplification of the first derived equation is quite small.

Ambiguous loss and disenfranchised grief in formal caregivers of people with dementia: Effectiveness of a training intervention with psychodrama

Formal caregivers of people with dementia may experience ambiguous loss due to the psychological loss of care recipients before their physical death. They may also experience disenfranchised grief when other people fail to acknowledge their losses. Since the number of studies addressing these topics is fairly restricted, this research investigates the phenomena of ambiguous loss and disenfranchised grief as observed within the staff of a care facility for people with dementia. Moreover, this research evaluates the impact of a psychodrama training course on the processing of such griefs. A mixed-method research design was used. For the quantitative section, the following variables were examined: caregiver grief, well-being, and burnout levels. Fifty-nine health professionals took part in the study. Before and after the psychodrama intervention, participants were interviewed and filled out questionnaires for longitudinal research. The training intervention has resulted in a reduction in formal caregiver ambiguous loss and an improvement of the well-being of participants, as well as in the acquisition of awareness and skills regarding grief, greater validation of one's grief and better communication skills. The training intervention with psychodrama seems to help manage loss experiences in staff working with people with dementia.

Analysis of Phenomenon of Plasticity Loss of Steel Core Made by Selective Laser Melting Method in Zone of Pressure Mould Conformal Cooling Channel.

This paper presents the results of testing the mechanical properties of maraging steel 1.2709 that were obtained by the SLM method under uniaxial and triaxial states of stress. The triaxial state of stress was realised by making circumferential notches in the samples with different radii of rounding. The specimens were subjected to two types of heat treatment, which consisted of ageing at 490 °C and 540 °C for 8 h. The results of the tests that were conducted on the samples were considered as references and compared with the results of the strength tests that were conducted directly on the SLM-made core model. Differences were found between the results of these tests. Based on the experimental results, the relationship between the equivalent strain of the specimen in the bottom of notch εeq and triaxiality factor η was determined. Function εeq = f(η) was proposed as a criterion for the decrease in the plasticity of the material in the area of the pressure mould cooling channel. Using the FEM method, equivalent strain field εeq and triaxiality factor η were determined in the conformal channel cooled core model. Based on the proposed criterion of plasticity loss and the results of numerical calculations, it was shown that the values of equivalent strain εeq and triaxiality factor η in the core that was aged at 490 °C did not meet this criterion. On the other hand, the values of strain εeq and triaxiality factor η did not exceed the safety limit when ageing was carried out at 540 °C. The plasticity loss method presented in this paper assumes that the value of the triaxiality factor in the vicinity of the channel is influenced by the shape, cross-sectional dimensions and trajectory of the channel axis. Using the methodology proposed in this paper, it is possible to determine the value of allowable deformations in the cooling channel zone and to determine whether the heat treatment applied to the SLM steel does not cause an excessive reduction in the plastic properties.

A distinct structure of TiC for electromagnetic interference shielding and thermal stability of SiTiOC ceramic nanocomposites

Materials capable of thermal stability electromagnetic interference (EMI) shielding have practical significance in the fields of aerospace. In this paper, a brand-new polymer-derived SiTiOC ceramic nanocomposites with tubular carbon was designed. The titanium atoms were uniformly introduced into the polysiloxane backbone by the transesterification between tetrabutyl titanate and silanol prepolymer, leading to excellent thermal stability properties. By controlling the pyrolysis temperature, a distinct structure of TiC was formed between the amorphous SiTiOC matrix and free carbon phase for enhanced electromagnetic interference shielding performance. More conductive paths were established, and the TiC structure initiated interfacial polarization and space charge polarization, contributing to the improvement of the dielectric loss and relaxation phenomena. Simultaneously, a total electromagnetic interference shielding efficiency of 27.85 dB at the entire X-band was reported for SiTiOC ceramic nanocomposites. A maximum SET of 38.59 dB was examined at around 12 GHz, suggesting that over 99.99% of the electromagnetic waves were shielded. The SiTiOC ceramic nanocomposites exhibited outstanding prospects in thermal stability electromagnetic interference shielding application in a severe environment.

Nonfragile Formation Control of Leaderless Unmanned Surface Vehicles With Memory Sampling Data and Packet Loss

This article, in the presence of sampling data and packet loss, is concerned with the formation regulation for a network of unmanned surface vehicles (USVs) within the leaderless framework. In-neighboring USVs' information is aperiodically sampled for broadcasting over interaction channels subject to constant transmission delay. A nonfragile control protocol is novelly constructed for seeking the desired formation with tolerating controller gain fluctuation. The introduction of a continuous switching signal with two values encouragingly governs the packet loss phenomenon. With the utilization of nonsingular transformation method, algebraic graph theory and Lyapunov–Krasovskii functional technique, one proves that the desired formation is achieved if a coupling relationship can be feasibly characterized by some sufficient conditions. For the description of global formation movement, a formation reference function in the nature of an unforced dynamic system with determined initial condition is promisingly derived. A simulation example is given to validate theoretical analysis.

Mainstreaming Parental Involvement in Post-Pandemic : Resolving Learning Loss with the Partnership Model in Elementary Schools

This research aims to find best practices for using the partnership model to solve learning loss during a pandemic in elementary schools. The method of research was descriptive with a qualitative approach. Collecting data using interview techniques. The main instrument in this research was the researcher himself. The informants in the study were twenty-seven teachers from nine elementary schools in the districts of Central Lombok, West Lombok, and the City of Mataram. The research stages consist of data collection, condensation, presentation, and conclusion. Data analysis was carried out using data collection, reduction, presentation, and concluding techniques. The validity of the data was checked using dependency techniques. The study results showed that the partnership model used effectively reduces the post-pandemic learning loss phenomenon in elementary schools. The partnership model was implemented by optimizing parental involvement in learning and involving parents in evaluating learning outcomes.

Reliability studies on bipolar transistors under different particles radiation

The reliability of silicon bipolar junction transistors (Si BJTs) and silicon germanium heterojunction bipolar transistors (SiGe HBTs) were studied under 80 MeV nitrogen (N6+) ions and 60Co gamma radiation in a total dose from 1 to 100Mrad at 300 K. Different DC electrical parameters namely Gummel Characteristics (IB, IC–VBE), excess base current (ΔIB), current gain (hFE), and output characteristics (IC–VCE) were studied before as well as after being subjected to radiations. Both radiations caused substantial degradation in parameters such as an increase in IB, a decrease in the hFE, and a decrease in ICsat. The parametric degradation is more in Si BJT (99% degradation in hFE after ion irradiation) when compared to SiGe HBT (45% degradation in hFE). The SRIM/TRIM simulations were employed to analyze the energy loss phenomenon and ion range in device structures. Annealing studies were also conducted to study the recovery behavior of irradiated devices. The influence of linear energy transfer (LET) of radiations on damage mechanism is also discussed based on irradiation and annealing results. The results show that SiGe HBTs are more radiation hardened than Si BJTs.