Simultaneous Occurrences Research Articles

Imaginary network motifs: Structural patterns of false positives and negatives in social networks

We examine the structural patterns in the cognitive representation of social networks by systematically classifying false positives and negatives. Although existing literature on Cognitive Social Structures (CSS) has begun exploring false positives and negatives by comparing actual and perceived networks, it has not differentiated simultaneous occurrences of true and false positives and negatives on network motifs, such as reciprocity and triadic closure. Here, we propose a theoretical framework to categorize three classes of errors we call imaginary network motifs as combinations of accurately and erroneously perceived ties: (a) partially false, (b) completely false, and (c) mixed false. Using four published CSS data sets, we empirically test which imaginary network motifs are significantly more or less present in different types of perceived networks than the corresponding actual networks. Our results confirm that people not only fill in the blanks as suggested in the prior research but also conceive other imaginary structures. The findings advance our understanding of perception gaps between actual and perceived networks and have implications for designing more accurate network modeling and sampling.

Quasi-in-situ observation and analysis of grain boundary evolution of GH4169 nickel-based superalloy during the micro-strain stage of thermal deformation

A systematic study was conducted to analyze the grain boundary microstructure evolution of GH4169 nickel-based superalloy during the micro-strain stage of thermal deformation. A quasi-in-situ EBSD (electron backscatter diffraction) approach was used for observation. Moreover, at a temperature of 1100 °C and a strain rate of 0.1 s−1, a continuous strain uniaxial compression experiment was carried out. We observed the development of the grain boundary structure and the grain boundary deformation. The experimental findings revealed that GH4169 underwent locally inhomogeneous thermal deformation during the micro-strain stage, and the simultaneous occurrences of grain boundary slip, grain rotation, and grain boundary migration, exhibiting microstructural diversity. The grain boundary structure changed continuously as a result of the random movement of high-angle grain boundaries. Twin grains displayed a stable structure during the migration of grain boundaries, and their content indicated a considerable decrease as the strain increased. This provides a basis for directing the design of grain boundary engineering since it suggests that twin boundaries are easier to migrate during thermal deformation. In addition, no evidence of dynamic recrystallization was found throughout the entire micro-strain stage and a <101>/<111> micro-texture was observed, which is compatible with common dislocation slips in face-centered cubic crystals. Then, on the basis of the transmission electron microscope images of the microstructure, the numerous forms of grain boundary deformation were rationally explained from the standpoint of the relation mechanisms among grain boundaries and dislocations. Finally, the synergistic mechanism of grain boundary slip and migration is established as the primary mechanism of thermal deformation in the micro-strain stage.

Prediction based fusion estimator-controller for an event-triggered multi-sensor cyber-physical systems

This article focusses on development of centralized fusion estimator-controller for event-triggered multi-variable(MV) multi-sensors(MS) cyber–physical systems. The unified mathematical model is developed, which is able to take care of simultaneous occurrences of packet loss in S-E and C-A channels and event-triggered conditions. The model uses current measurements and state predictions to handle communication flaws and untriggered sensor measurements. The centralized fusion estimator is developed using orthogonal projections for augmented MV-MS system, offering a globally optimal solution. The proposed fusion estimator possesses linear minimum variance property and it is unbiased. Feedback control is designed and it ensures mean square stability. Zero estimate error concept is introduced to reduce the computation burden, network congestion and energy utilization. The novel residual-based cyber-attack detection algorithm is developed. The proposed method is validated for cruise control system and performance is compared with other popular works.

Coupling effect of vortex-induced vibration and local scour of double tandem pipelines in steady current

Submarine pipelines are critical for offshore oil and gas production. However, when these pipelines are located on the seabed, they are susceptible to simultaneous occurrences of local scour and vortex-induced vibration, which impose a significant threat to pipeline safety and integrity. To address this issue, our study investigates the coupling effect of vortex-induced vibration and local scour using Flow-3D. Specifically, we explore the influence of the gap ratio on the vibration and local scour of the pipelines. Our findings reveal that the horizontal gap between the pipelines significantly affects the depth and profile of the scour pits. When the horizontal gap ratio is G/D = 2, pipeline vibrations promote the merging of scour pits. And as the interference effect between the two pipelines weakens with the increase of horizontal gap, the depth difference of scour pits below the fixed and vibrating double pipelines gradually decreases. Moreover, when G/D ≥ 3, the vortices falling off the upstream and downstream pipelines are discharged separately. This results in weak interference between the pipelines and the formation of two independent scour pits.

Developing an earthquake model based on simultaneous peak ground acceleration occurrences using the D-vine copula approach

Developing an earthquake model based on simultaneous peak ground acceleration occurrences using the D-vine copula approach

Unconventional quantum criticality in a non-Hermitian extended Kitaev chain

We investigate the nature of quantum criticality and topological phase transitions near the critical lines obtained for the extended Kitaev chain with next nearest neighbor hopping parameters and non-Hermitian chemical potential. We surprisingly find multiple gap-less points, the locations of which in the momentum space can change along the critical line unlike the Hermitian counterpart. The interesting simultaneous occurrences of vanishing and sign flipping behavior by real and imaginary components, respectively of the lowest excitation is observed near the topological phase transition. Introduction of non-Hermitian factor leads to an isolated critical point instead of a critical line and hence, reduced number of multi-critical points as compared to the Hermitian case. The critical exponents obtained for the multi-critical and critical points show a very distinct behavior from the Hermitian case.

A combined experimental and computational chiroptical approach to establish the biosynthesis and absolute configuration of licochalcone L

Often, chiral natural products exist as single stereoisomers; however, simultaneous occurrences of both enantiomers can exist in nature, resulting in scalemic or racemic mixtures. Ascertaining theabsolute configuration (AC) of natural products is pivotal for attributing their specific biological signature. Specific rotation data commonly characterize chiral non-racemic natural products; however, measurement conditions, viz., solvent and concentration, can influence the sign of specific rotation values, especially when characterizing natural products possessing small values. For example, licochalcone L, a minor constituent of Glycyrrhiza inflata, was reported with a specific rotation of [α]D22= +13 (c 0.1, CHCl3); however, not establishing the AC and the reported zero specific rotation for an identical compound, licochalcone AF1, resulted in debatable chirality and its biogenesis. In this study, a combined experimental and computational chiroptical approach involving specific rotation and electronic circular dichroism (ECD) data, supported by time-dependent density functional theory (TDDFT), were effectively utilized to establish the AC of licochalcone L as the (E, 2″S)-isomer. Establishing the 2″S absolute configuration permitted the conception of a reasonable biosynthetic pathway involving intramolecular ‘5-exo-tet’ ring opening of a chiral oxirane to form chiral licochalcone L in G. inflata.

Experimental study of thermal runaway propagation along horizontal and vertical directions for LiFePO4 electrical energy storage modules

With the growing installation of electrochemical energy storage systems, the safety issues of lithium-ion batteries have attracted extensive attention. To identify the development of thermal failure in energy storage systems, horizontal and vertical thermal runaway (TR) propagation characteristics of lithium-iron-phosphate battery modules with different connections are systematically investigated herein. Once TR occurs in the initial battery, it initially propagates to subsequent batteries along the horizontal direction, followed by vertical propagation to the upper batteries. Particularly, the almost simultaneous occurrences of TRs in the upper batteries accompanied by extreme combustion are observed during vertical propagation, exhibiting huge thermal hazards. The maximum temperature and heat release of upper batteries are 548.3 °C and 490.7 kJ, much higher than that of lower batteries with values of 423.2 °C and 217.7 kJ, demonstrating upper batteries experience severer TR. Moreover, the heat generated by the combustion of the individual battery can increase temperatures of upper batteries by 30 °C–40 °C, which is insufficient to cause vertical TR propagation, while TRs of upper batteries will eventually be triggered with the proceeding of horizontal TR propagation. The results provide valuable information for TR propagation between battery modules and benefit the safety application of energy storage systems.

Efficiency and effectiveness of global onshore wind energy utilization

The progress of onshore wind expansion varies globally, as often expressed by a country’s installed capacity and capacity factor. However, installed capacity and capacity factor do not allow conclusions about how effectively and efficiently countries use their spatially diverse wind potential. It is unknown how far wind energy expansion is and whether the countries use the available potential in the best possible way. Thus, this study aims to quantify and compare the wind potential use effectiveness and efficiency for the 40 countries with the highest installed capacity in 2021. A global wind turbine site dataset and the wind farm potential index were used for estimating the suitability of current wind turbine sites. The wind potential use efficiency was calculated by comparing the (1) distributions of the wind farm potential index at wind turbine sites with (2) distributions of the wind farm potential index of the countries as a whole by the Kolmogorov-Smirnov test statistic. The capacity-to-suitable-area ratio defined the wind potential use effectiveness. The results reveal that 81.9% of the global onshore wind turbine fleet operates at suitable sites. Simultaneous occurrences of high effectiveness and efficiency are not given in any country: China, Brazil, and Italy use their wind potential more efficiently than many other countries. The USA and India adequately consider the wind resource efficiency for wind turbine siting. Germany has the highest effectiveness despite low efficiency. The results reveal how critical it is to quantify the progress of wind energy expansion based on the effectiveness and efficiency, not only the installed capacity and capacity factor.

Time series modeling of rainfall and lake elevation in relation to breaching events at the Lake Earl and Tolowa lagoon system, coastal northern California

I evaluated trends in spatial and temporal variability in historical levels of rainfall, water elevation, and breach events for lakes Earl, Tolowa, and their combined lagoon system along the coast of northern California. I examined the efficacy of time series analyses to model and forecast rainfall and lake elevation at a regional scale from 2008 to 2021. I employed semi-parametric Generalized Additive Model regression to investigate the historical relationship between anthropogenic breaching of the lagoon and simultaneous occurrences of environmental parameters to better understand conditions surrounding each breach event. Evaluation of the central tendency of rainfall and surface lake elevation showed high fluctuations in their mean, positive skewed, and leptokurtic curves. Augmented Dickey-Fuller tests found that seasonal rainfall was stationary, but surface lake elevation attained stationarity only after the first seasonal difference. Decomposition of each time series and MannKendall and Sen’s slope estimators, found a significant decreasing trend in seasonal surface lake elevation but no trend was found in rainfall. Seasonal Autoregressive Integrated Moving Average (SARIMA) time series analysis and diagnostic tests of stability and reliability found best fit models for rainfall (SARIMA[1,0,0] [2,1,1]12) and surface lake elevation (SARIMA [1,1,2] [1,0,0]12) used to forecast future values for each parameter. Multiple regression of variables obtained at each breach event showed that the proportion of variance (55.0%) and null deviance (72.1%) explained by the combination of rainfall, hightide, and wave height was the “best” model with the lowest Generalized Cross-Validation statistic of all other models evaluated. All models agreed that rainfall was the most significant factor within each set of predictor attributes used to model surface lake elevation. A declining trend in surface elevation in combination with variation in the historical area and extent of wetland plant communities may be attributable to systematic breaching of the lagoon annually.

Occurrence of familial Mediterranean fever in haemophilia patients.

This is the first study of simultaneous occurrences of Familial Mediterranean Fever (FMF) in patients with haemophilia. The aim was to investigate the frequency and clinical characteristics of FMF in patients with severe haemophilia. Our study included 30 patients with severe haemophilia (26 haemophilia A and four haemophilia B). All 30 patients are screened for MEFV genotypes in FMF according to the new Eurofever/PRINTO diagnostic criteria. All cohorts were genetically tested for FMF and thrombophilia. Eight (26%) of 30 haemophilic patients were diagnosed with FMF. Six different heterozygous FMF mutations including M694V (n=2), E148Q (n=2), V726A(n=1), P369S (n=1), E148Q/K695R (n=1) and E148Q/M694I (n=1) were identified. Seven had haemophilia A and only one had haemophilia B. Four (50%) patients had a positive family history and three of them had extraarticular findings specific to FMF. Only one haemophilia B patient received colchicine. Target joints in the knee, ankle, and elbow were identified in three FMF patients. The number of target joints in eight patients with FMF was significantly lower than in twenty-two patients without FMF (p<.05). The annual number of suspected joint bleedings in FMF patients admitted to the hospital was 40; however, 15 (37.5%) were documented bleedings in ultrasounds. Hereditary thrombophilia was detected in seven of eight patients. Our data indicate that screening for FMF may be useful in patients with haemophilia who develop arthritis without prominent bleeding and have a positive family history in many Mediterranean countries, including Turkey.

Dynamic-memory event-based asynchronous security control for T-S fuzzy singular semi-Markov jump systems against multi-cyber attacks

In this paper, the design of reliable asynchronous controller for a class of Takagi Sugeno (T-S) fuzzy singular semi-Markov jump system (SSMJS) with an dynamic-memory event-triggered (DMET) transmission scheme against multiple cyber attacks. In order to improve the reliability of data transmission, the dynamic-memory event-triggered transmission scheme is proposed. A multi-cyber attacks model is established to formulate the simultaneous occurrences of deception attacks and DoS attacks. Since the modes information can not be acquired by the actual controller in real-time, the hidden Markov model (HMM) is used to describe the asynchronous phenomenon. The asynchronous controller with partly known conditional probability is properly designed, which reduces the conservatism to some extent. According to methods of stochastic Lyapunov functional and free-weighting matrices, the criteria of exponentially admissible for closed-loop system is obtained. Based on a set of linear matrix inequalities, a unified co-design method for the asynchronous controller with partial known conditional probability under the dynamic-memory event-triggered transmission scheme is proposed. Finally, the effectiveness of the proposed method is verified by comparing DMET scheme with other triggering schemes.

Diagnostic challenges for the distinction of high-grade prostatic adenocarcinoma and high-grade urothelial carcinoma of simultaneous occurrences - A literature review

Abstract: Two of the most prevalent types of cancer in men are prostate adenocarcinoma and urothelial carcinoma. Both can appear separately in the prostate and bladder, simultaneously as separate tumors affecting either organ or sporadically as a collision tumor. Distinguishing these tumors by the pathologist can be challenging, especially when the high-grade, poorly differentiated forms infiltrate the surrounding organs. The correct approach by the pathologist is important due to the different treatment modalities for these two entities. This review of the literature gives a comprehensive overview, our succinct understanding of the significance of correctly differentiating between these two tumors, the challenges involved in doing so, and the best collection of crucial and useful immunohistochemical markers for better diagnostic performance.The scientific papers used in this review were retrieved from the PubMed and Google Scholar databases. All the studies in this review have recently been peer-reviewed and published in academic journals. The literature was sifted through to find the most relevant and up-to-date information for medical professionals, specifically pathologists. The review concluded that: 1) Prostatic and urothelial markers such as NKX3.1, p63, thrombomodulin, and GATA3 are very useful for distinguishing prostatic adenocarcinoma from urothelial carcinoma. 2) Prostate Specific Antigen (PSA) is a good (clinical) screening tool, but because of its inverse relationship with tumor grade (the higher the grade, the lower the sensitivity of PSA staining), it is not recommended for high-grade tumor differentiation. 3) HMWCK (34βe12) and p63 are said to be more effective than thrombomodulin and S100p in detecting urothelial cancer. 4) Thrombomodulin is only moderately sensitive to urothelial carcinoma. 5) Cytokeratins 7 and 20 can be positive in both urothelial carcinoma and prostatic adenocarcinoma, therefore their use is restricted. The optimal combination of these markers may improve the ability to distinguish these tumors.

네트워크 이론 기반 국내학회 네일연구 트랜드에 관한 연구

This study analyzed the research trends centered on 192 keywords, with 96 keywords for 20 years, 60 keywords for 21 years, and 36 keywords for 22 years from 5 academic societies up to the last 3 years (20-22 years) according to the Korean Journal Standards (KCI). The keywords for 22 years are written only in the first half of June. The number of simultaneous occurrences of keywords by year was analyzed for frequency, and network analysis was performed using NodeXL to derive research keywords that are being studied in common at 5 conferences. the results are as follow. First, the research keywords that appeared the most in 20 years were nail design, three-dimensional art, and flat art. In 21, it was nail design, nail art, and three-dimensional art, and in 2022, it appeared as nail design, self-nail, and consumer value. In common, nail design was the center of research. As a result of the network analysis, the sub-elements of nail design showed expression methods, techniques, expression diversity, and patterns.

Application of Dynamic-Task-Based Hazard Identification Method to Remote Operation of Experimental Ship Shinpo

Recently, the development of autonomous ships has been progressing worldwide; thus, it is essential to ensure the safety of these ships for their successful realization. In previous studies, task-based hazard identification (HAZID) methods were developed as safety assessment methods for autonomous ships to identify hazards related to the tasks of ship operators. In this paper, a dynamic-task-based HAZID (DTB-HAZID) method, which is an improvement on the previously developed task-based HAZID method, is proposed, and the results of the risk analysis obtained from applying this method to a small experimental ship, Shinpo, are reported. The DTB-HAZID method was designed to analyze time-related hazards such as task delays and the simultaneous occurrences of tasks. To achieve this, the activity diagram, which is a type of unified modeling language (UML) model, was introduced to create task flow diagrams. In the risk analysis, first, the tasks of the operator who remotely navigated Shinpo were analyzed, and the corresponding task flow diagrams were created. Then, the time-related hazards were identified with reference to these diagrams. Finally, the obtained hazards were reviewed, and the applicability of the proposed method in hazard analysis from the perspective of time was discussed.

Genesis and simultaneous occurrences of the super cyclone Kyarr and extremely severe cyclone Maha in the Arabian Sea in October 2019

Genesis and simultaneous occurrences of the super cyclone Kyarr and extremely severe cyclone Maha in the Arabian Sea in October 2019

Multiple-Actuator Fault Isolation Using a Minimal ℓ1-Norm Solution with Applications in Overactuated Electric Vehicles.

A multiple-actuator fault isolation approach for overactuated electric vehicles (EVs) is designed with a minimal -norm solution. As the numbers of driving motors and steering actuators increase beyond the number of controlled variables, an EV becomes an overactuated system, which exhibits actuator redundancy and enables the possibility of fault-tolerant control (FTC). On the other hand, an increase in the number of actuators also increases the possibility of simultaneously occurring multiple faults. To ensure EV reliability while driving, exact and fast fault isolation is required; however, the existing fault isolation methods demand high computational power or complicated procedures because the overactuated systems have many actuators, and the number of simultaneous fault occurrences is increased. The method proposed in this paper exploits the concept of sparsity. The underdetermined linear system is defined from the parity equation, and fault isolation is achieved by obtaining the sparsest nonzero component of the residuals from the minimal -norm solution. Therefore, the locations of the faults can be obtained in a sequence, and only a consistently low computational load is required regardless of the isolated number of faults. The experimental results obtained with a scaled-down overactuated EV support the effectiveness of the proposed method, and a quantitative index of the sparsity condition for the target EV is discussed with a CarSim-connected MATLAB/Simulink simulation.

Stability and Deformation Responses of Earth Slopes Subjected to Multiple Natural and Manmade Hazards

Multiple hazards such as rainfall, earthquake, and excavation may occur simultaneously, and the stability (factor of safety) and deformation (movement) behaviors must be investigated to prevent loss of life and properties. In this study, the stability and deformation behaviors of earth slopes subjected to the individual and simultaneous occurrence of these events are investigated using a coupled Geotechnical–Hydrological finite-element method (FEM). First, the finite-element model was validated against a case history and a widely used limit-equilibrium method (LEM) considering site-specific soil properties and rainfall records. The shape and the size of the critical failure surface obtained from the field investigation coincided well with those calculated using FEM and LEM. Also, the predicted onset of slope failure (after eight days of rainfall) coincided well with the real-time occurrence of the slope failure. The validated finite-element model was then used to predict the stability and deformation responses of earth slopes subjected to several possible scenarios, including individual and simultaneous occurrences of these events. The rainfall–excavation scenario indicated that the slope would have failed two days before the recorded time if the slope had a vertical cut width of 4.25 m. The rainfall–earthquake hazard scenario caused the slope to move horizontally by 799 mm. The parametric study conducted by varying the friction angle of the slope soil by ± one standard deviation (STD) with 10% covariance showed that the slope would have failed one day later and two days prior to the mean friction angle, respectively, when subjected to rainfall. Also, varying the friction angle by +1 STD and −1 STD failed the slope for 0.5 m above and 0.4 m below the cut width for the slope with mean friction angle when subjected to excavation, respectively. Further, the percent increase in the horizontal movement of the slope soil with friction angle by +1 STD and −1 STD compared to mean friction angle was 56% and 18%, respectively, when subjected to earthquake.

Daytime F Region Echoes at Equatorial Ionization Anomaly Crest During Geomagnetic Quiet Period: Observations From Multi‐Instruments

AbstractBy using Qujing very high frequency radar (25.6°N, 103.7°E, magnetic latitude 16.1°N, magnetic longitude 177.0°E), daytime F region echoes were reported at equatorial ionization anomaly crest on 26 June 2020. Radar interferometry experiment was performed during the observation period. The observed results show that the spatial distributions of daytime F region echo pattern were about 150 km, 200 km, and 180 km in the zonal, meridional, and height extents, respectively. In addition, we observed a remarkable eastward drift of F region echoes with a mean velocity of about 50 m/s. To investigate the possible generation mechanism of daytime F region echoes, simultaneous occurrences of ionospheric disturbance and atmospheric gravity wave activities were presented by combining with the observations of ionosonde, global position system stations and FY‐4A satellite. The existence of gravity wave from the deep convective activities in the lower atmosphere was confirmed by using FY‐4A satellite measurements. The gravity wave signatures were also observed in the time series of virtual height deviations of sporadic E (dhES) and total electron content near the region where the F region echoes. We surmise that ionospheric disturbance in the F region could be excited during atmospheric gravity wave activities. Then the large‐scale ionospheric disturbance could further evolve into small‐scale irregularity producing radar echoes through the non‐linear cascade process.

Increase in the number of explosive low‒level cyclones around King George Island in the last three decades.

This paper documents an increase in the number of observed explosive cyclones (EC) at King George Island, South Shetland Islands, Antarctica, over the 1989‒2020 period. In ECs at 60o latitudes the surface atmospheric pressure drops ≥24 hPA in 24 hours. The annual EC frequency time series shows a significant positive trend of ~2.7 cyclones/decade, with a break in 2003 and average numbers of 7.3 and 11.8 events before and after that break, respectively. The increase follows closely earlier documented global sea surface temperature (SST) anomaly trends for the 1981‒2018 period, partially attributed to global warming and to the Pacific Decadal Oscillation (PDO). Connections between EC frequency and SST might occur through variations in SST in the southeastern Pacific and southwestern Atlantic, with anomalous cold conditions favoring an increase in ECs. We also found close relations between the number of ECs with simultaneous occurrences of PDO and Atlantic multidecadal oscillation in opposite phases, so that after 2003 they were in the cold and warm phases, respectively, and vice-versa before 2003. Both low-frequency modes seem to modulate the number of ECs. As per the authors knowledge these results have not been discussed before and may help climate modeling studies and weather forecasts.