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Distributed Denial-Of-Service (DDoS) attacks are one of the all the more difficult security issues on the Internet today. They can without much of a stretch, fumes the assets of the potential Victims. The issue is much more extreme since the aggressors regularly produce their IP delivers to shroud their character. The current guard mechanism against DDoS attacks, the attack traffic will be filtered at the victim’s side. For this situa- tion, regardless of whether the attacking traffic is filtered by the victim, the attacker may achieve the objective of blocking access to the victim’s bandwidth. IP-Trace back ap- proaches enable the victim to trace back to the wellspring of an attack and they will not be able to minimize the attack when the attack is in progress. Hence is to minimize the quan- tity of malicious packets entering into the network we put forth a quantum annealing technique to identify and alleviate the DDoS attack. The attack messages are minimized by utilizing client puzzle as a part of the ingress router; the path fingerprint is used at the egress side. Simulation studies prove that the proposed mechanism is optimally successful in recognizing and mitigating the DDoS attacks.

Cognitive radio is an emerging technology, aimed at efficient use of the scarce radio spectrum. In cognitive radio networks (CRNs), spectrum licensed to the primary users (PUs) is shared by the secondary users (SUs) which affects the performance of the network. This paper proposes a novel spectrum management scheme for CRNs, where heterogeneous secondary real-time and non-real time users compete for the available channels with primary users and utilize two types of buffers under the probability retrial policy. To enhance the quality of service (QoS) for the secondary users (SUs), spectrum handoff and call buffering strategies with retrial policy are employed jointly so that SUs that would otherwise be blocked or forcibly dropped could be queued and possibly served later. The whole system is modeled using a multi-dimensional continuous-time Markov chain (CTMC) and accordingly, the QoS performance metrics are derived. Numerical results are presented which illustrate that the provision of queues under the proposed retrial policy increases overall network resource utilization and throughput while decreasing blocking and dropping probabilities.

Made available in DSpace on 2022-05-01T06:31:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The delay in signal transmission for oscillator networks influences in the synchronization, getting oscillatory behavior. The synchronization occurs by the phase-locked loops (PLL), synchronizing the local oscillator with a reference phase and frequency. The oscillators are implemented in data and telecommunications communication systems, as elements (nodes) for distribution of time signals (clock). In the work is implementated the time signal distribution network, with three nodes, in order to establish a common time base, with adjustment of disturbance in clock. The phase detection process generates a periodic oscillation called double-frequency jitter (DFJ). The DFJ is inevitable, appearing even with the PLL operating in the blocking range. Therefore, this work aims to study the effect of the double frequency oscillation on a network with signal transmission delay, its influence on the synchronous states of network, and the performance of oscillators to recover the common time base of clock, when disturbed. Institute of Sciente and Technology São Paulo State University-UNESP, Av. Três de Março 511 Fedeal University of ABC-UFABC, R. Arcturus 3 School of Engineering São Paulo State University-UNESP, Av. Eng. Luís Edmundo Carrijo Coube, 14-01 Institute of Sciente and Technology São Paulo State University-UNESP, Av. Três de Março 511 School of Engineering São Paulo State University-UNESP, Av. Eng. Luís Edmundo Carrijo Coube, 14-01

Power swings appear as a result of sudden addition or removal of heavy loads, switching, cutoff of a parallel line, and reclosing. These swings can affect the protective zones of distance relays, causing them to malfunction and erroneously cut off healthy lines from the grid. This paper proposes a new solution for detecting power swings and preventing this malfunction based on the variance of data sampled from the current signal. The lack of any signal processing phase in the proposed solution makes it computationally light and thus suitable for implementation in distance relays. In addition, the method's performance is not affected by the presence of noise in the sampled signal. The method is able to detect power swings of stable, unstable, and multi-mode variety. In comparison with some of the latest works in the field of power swing detection as well as conventional methods, it is demonstrated that the method outperforms them in terms of response time, the ability to detect different varieties of the power swing, and the ability to detect different varieties of faults that may occur simultaneously with a power swing.

Atmospheric blocking plays an important role in modulating mid-latitude weather, in particular in the Northern Hemisphere (NH). Trend analysis of atmospheric blocking for both hemispheres by using Sen’s Innovative Trend Analysis (ITA) is performed in this study. The blocking data archived in the University of Missouri covers the period of 1968–2019 for the NH and 1970–2019 for the Southern Hemisphere is used in the study. Block occurrence, duration and blocking intensity (BI) is analysed by classifying the NH (and SH) into three groups according to the preferred blocking locations: Atlantic, Pacific and Continental (Atlantic, Pacific and Indian). In the NH, blocking intensity showed mixed results. It showed a decreasing trend for the entire hemisphere and Atlantic Region, whilst a different trend was shown for different BI clusters. For blocking numbers and duration, the entire hemisphere and regions showed increasing trends. These increasing trend values were also statistically significant. In the SH, blocking intensity showed a decreasing trend for low clusters, whilst medium and high cluster increased for the entire hemisphere. Block duration showed an increasing trend for the entire SH. Block numbers showed increasing trends, except for one point in the low cluster. Blocking characteristics showed different trends for different preferred blocking locations. Increasing trends of blocking numbers for the overall SH and Pacific region are statistically significant at 95% level. Increasing trends of blocking duration for the overall SH, Atlantic and Pacific region are statistically significant at 90%, 95% and 95% level, respectively.

We give a mathematical description of the initial stage of both axles skidding for a wheeled vehicle on a bend that arises in the case of blocking or slipping of wheels of one of its axles. It is shown that within the framework of Zhuravlev’s model of friction, which takes into account the moments of spinning friction (they appear as a result of interaction of the wheels with the reference plane), the vehicle skidding is less than for the Coulomb friction model.

Atmospheric blockings are generally associated with large-scale high-pressure systems that interrupt west-to-east atmospheric flow in mid and high latitudes. Blockings cause several days of quasi-stationary weather conditions, and therefore can result in monthly or seasonal climate anomalies and extreme weather events on the affected regions. In this paper, the long-term coupled CERA-20C reanalysis data from 1901 to 2010 are used to evaluate the links between blocking events over the North Atlantic north of 35° N, and atmospheric and oceanic modes of climate variability on decadal time scales. This study indicates more frequent and longer lasting blocking events than previous studies using other reanalyses products. A strong relationship was found between North Atlantic blocking events and North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO) and Baffin Island–West Atlantic (BWA) indices, in fall, winter and spring. More blocking events occur during the negative phases of the NAO index and positive phases of the BWA mode. In some situations, the BWA patterns provide clearer links with the North Atlantic blocking occurrence than with the NAO alone. The correlation between the synchronous occurrences of AMO and blocking is generally weak, although it does increase for a lag of about 6–10 years. Convergent cross mapping (CCM) furthermore demonstrates a significant two-way causal effect between blocking occurrences and the NAO and BWA indices. Finally, while we find no significant trends in blocking frequencies over the last 110 years in the Northern Hemisphere, these events become longer lasting in summer and fall, and more intense in spring in the North Atlantic.

The photovoltaic power generation system for input blocking was manufactured to be used for blocking control by separately manufacturing two circuits of DC 180[V] PV strings for smooth experimentation. By attaching the circuit proposed in this study to the separately fabricated circuit input part, interruption and input were repeated, and the presence or absence of an arc and the magnitude of the voltage applied to the cut-off circuit were analyzed. It was possible to suppress constant heat generation by using a relay with a low switching voltage at all times, and offset the high voltage with a low voltage of 2[V] with a parallel type IGBT only when blocking was necessary. By attaching a parallel type IGBT, arc generation could be eliminated, and a safe and efficient cut-off circuit could be constructed.

Shamash et al. probe the navigational strategies mice use as they escape from a threat. By systematically placing and removing obstacles blocking their initial path, the authors find evidence that mice memorize intermediate ‘subgoal’ locations to find their way home.

With the development of many devices that support high-speed wired and wireless Internet, it has been universalized to upload and download various kinds of social multimedia information. However, image data including sensitive personal information are easily exposed to Internet users. In this study, the algorithm is introduced to make it possible to exclude background regions from various types of input color images, to robustly detect the target regions including personal information, and then effectively protect the detected target regions through context-adaptative blocking. In this study, the background regions are first excluded from input color images, and then only the target regions including personal information are robustly segmented on the basis of human skin color. Subsequently, the detected target regions are effectively blocked in the way of selecting regional blurring adaptively in line with surrounding situations, and therefore it is possible to prevent personal information from being exposed. The experimental result of this study reveals that the proposed method robustly blocks the target object regions including personal information of input images in line with surrounding situations. The algorithm proposed in this study is expected to be applied practically to many fields associated with image processing, such as video surveillance, video monitoring, and target object covering.

Extreme maximum (Tx) and extreme minimum temperature (Tn) frequency distributions during summer and winter for blocked conditions were analyzed within Turkey during the period from 1977 to 2016 by using observational data. The Tx (0.5–0.8%) and Tn (0.4–2.0%) frequencies vary between these values for the entire period during summer. However, Tx varies between 0.0 and 1.0, while Tn varies between 0.8 and 2.4 during winter. It is quite clear that atmospheric blocking has a greater cooling effect during winter. The maximum values for Tx and Tn are observed when the block center located within the easternmost sector impacting Turkey for summer. The maximum Tx frequency is observed in association with blocking in the westernmost sector, and the maximum Tn frequency is observed with blocking in the easternmost sector impacting Turkey during the winter season. Block intensity has almost no impact on Tx frequency although it has enhancing effect on Tn frequency during the summer. For winter, block intensity has a decreasing effect on both the maximum Tn and maximum Tx. The maximum Tx and Tn values increase with the block size for the summer. During the winter, the maximum Tx frequency decreases with the increase in the size of a blocking event; however, the greatest Tn frequency is observed within the 0°–30° E sector and lowest within the 30° E–60° E sector. The block duration has an enhancing influence on the maximum Tx value, while maximum Tn is observed during short-duration events and a minimum is observed during moderate-duration events during the summer season. For the winter season, the block duration has a decreasing effect for Tx frequencies and increasing effect for Tn.

Modulation of Large-conductance cationic (LCC) channel currents through the inner nuclear membrane of rat Purkinje neurons by gallamine was estimated using analysis of the amplitude histograms. A kinetic scheme consisting of one open state and one blocked state of the channel was used. The search for optimal kinetic parameters of the truncated model was performed for the analysis of the blocking effect. The estimated rate constants of blocking and unblocking by 100 μM gallamine at –40 mV were 17880 ± ± 975 and 12790 ± 922, respectively. The obtained data show that gallamine is a fast blocker of the above channels; blocking is accompanied by ion current fluctuations suitable for the analysis using the two-state model if contribution of the events formed by intrinsic ion channel activity can be neglected.

In order to evaluate the effects of blocking patterns on the duration of frost waves across Iran, the minimum daily temperatures of 60 weather stations were collected from 20 March 1968 to 21 June 2014. The findings, which were obtained based on the distribution tables of reported temperatures and their frequency variation graphs, resulted in identifying 114 frost waves. We obtained the daily weather maps at 500 hPa from NCEP/NCAR during the peak days of durable frosts, and it was revealed that the formation of low pressures over 20°-70°E and the dominant southwest-northeast troughs at 500 hPa facilitated the influx of cold air from both eastern Europe and central Siberia toward Iran, leading to the average frost duration of 12.4 days. Furthermore, low-pressure centers appeared in a dipole pattern in northern Iran over Caspian Sea and created durable frosts with an average duration of 15.4 days. The effect of omega shaped pattern of the geopotential height on durable frosts demonstrated a sharp difference with two recent patterns leading to the frost occurrence with a 13.3-day duration averagely. Additionally, the slow speed of cold western currents in the rex type of blocking from 30° to 50°N caused durable frosts of 14.3 days. Also, we found a specific reduction in the frequency of blocking patterns, which has occurred in the past four decades. Mostly, the blocking and non-blocking patterns cause long- and short-duration frosts over Iran, respectively.

The conventional half-bridge submodule (HBSM)-based multilevel modular converter (MMC) cannot block DC faults. To solve this problem, a novel flexible overhead-line high-voltage direct current (HVDC) transmission converter station topology is proposed in this study, which provides DC fault blocking capability. By adding blocking submodules (SMs) onto the positive and negative DC buses of a conventional HBSM converter station, a rapid fault current blocking can be achieved in the case of a DC bus short circuit. The DC fault blocking principle of the proposed topology and the rapid fault blocking capability of the blocking SM are analyzed. The quantity of required major components is also calculated. In addition, the IGBT, the system loss and the control complexity quantities are comprehensively compared with those of existing topologies. The validity of the proposed topology is demonstrated based on simulation and experimental studies.

Compounds 3a [1-(3′,4′-methylenedioxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline] and 3b [1-(6′-bromo-3′,4′-dimethoxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline] demonstrated dose-dependent (5-75 μM) negative inotropic effects. Compound 5 [1,3-bis-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin- 1-yl)propane] demonstrated a two-phase inotropic effect. The experimental results and a literature analysis suggested that the negative inotropic effects of the tested compounds (3a, 3b, 5) could be due to their influences on the [Ca2+]i concentration through blocking of cardiomyocyte Na+- and Ca2+-channels. The positive inotropic effect of free base 5 could be related to modulation of cardiomyocyte muscarinic receptor activity.

Cognitive radio (CR) is a hopeful technology to sort out spectrum scarcity and underutilization problem in ad hoc networks. With the help of cognitive radio technology, unlicensed users can efficiently utilize the unused part of heterogeneous licensed spectrum. In this article, we present a three-dimensional (3D) Markov chain analysis for spectrum management scheme under heterogeneous licensed bands of two different licensed spectrum pools in cognitive radio ad hoc networks. We present the concept of interpool and intrapool spectrum handoff in the proposed model and derive blocking probability, dropping probability, non-completion probability, and throughput to estimate the performance of the secondary users under heterogeneous licensed spectrum environment. The impact of secondary users dynamic along with the primary users’ activity model on the performance measuring metrics in terms of blocking probability, dropping probability, non-completion probability, and throughput for three different cases is also investigated. The proposed model offers significant improvement in the performance of secondary users under heterogeneous licensed spectrum environment in a CR ad hoc network.

Background Everolimus is a kind of mTOR inhibitors. Activated mitogen-activated protein kinase interacting kinases/eukaryotic translation initiation factor 4E (MNK/eIF4E) axis plays a crucial role in resistance to Everolimus in non-small cell lung cancer (NSCLC). Typically, eIF4E phosphorylation increased by mTOR inhibitors was mainly mediated by MNKs. But the mechanisms are poorly understood. Recently, extensive reprogramming of miRNA profiles has also been found after long-term mTOR inhibitor exposing. Our previous studies have confirmed that tumor suppressor miR-7-5p was decreased in A549 cells after treatment with Everolimus. Exactly, MNK1 is the target of miR-7-5p. Here, we investigated the biological functions and potential molecular mechanisms of miR-7-5p in the NSCLC undergoing treatment with Everolimus. Methods miR-7-5p level and expression of main markers of MNK/eIF4E axis were evaluated by qRT-PCR, western blot, in situ hybridization, and immunohistochemistry on NSCLC cell lines and human NSCLC samples. Proliferation, migration and invasion of NSCLC cells in culture were explored by Colony formation, CCK-8, Wound healing and Transwell assays. NSCLC cell tumorigenicity was assessed by xenotransplants in nude mice. Targeted binding of miR-7-5p to MNK1 was confirmed by the Dual-luciferase reporter assay. And the isolation and identification of exosomes were investigated by Invitrogen™ Total Exosome RNA Isolation Kit, western blot, transmission electron microscopy and Zetasizer Nano ZS90 instrument. Results Everolimus targeted mTORC1 inducing NSCLC cells to secrete miR-7-5p-loaded exosomes in Rab27A and Rab27B dependent manners. Loss of intracellular miR-7-5p induced phosphorylation of MNK/eIF4E axis, but supplement of extra exosomal miR-7-5p could reverse it. Of note, both lower expression of miR-7-5p and elevated MNK1 protein were associated with poor prognosis of NSCLC. Both endogenous miR-7-5p and exo-miR-7-5p enhanced the therapeutic efficacy of Everolimus through inhibiting the proliferation, migration, and metastasis of NSCLC in vitro and vivo. Combination of miR-7-5p with Everolimus induced apoptosis to exhibit a synergistic anticancer therapeutic efficacy via dual abrogation of MNK/eIF4E and mTOR in NSCLC. Conclusion Everolimus decreases the intracellular miR-7-5p levels through release of miR-7-5p loaded exosomes from NSCLC cells in Rab27A and Rab27B dependent manners. Either endogenous miR-7-5p or exo-miR-7-5p combined with Everolimus can enhance the anticancer efficacy via targeting MNK/eIF4E axis and mTOR. Therefore, exosome-mediated miR-7-5p delivery combined with Everolimus may be considered as a promising novel combined therapeutic strategy for NSCLC.

In this paper, Schottky-drain reverse-blocking AlN/AlGaN HEMTs with drain field plate (FP) have been investigated by Silvaco-ATLAS tools. For HEMTs without FP, with the increase of Al mole fraction in AlGaN channel from 0 to 0.5, the reverse-blocking voltage increases from −158 V to −720 V. By using the drain field plate technique, a second electric field peak is introduced and the reverse-blocking voltage can be improved. Combined with the optimization of the SiN passivation thickness, optimal electric field management can be achieved to obtain the highest reverse-blocking voltage devices. Since HEMTs with different Al mole fractions possess different critical electric field values, the optimal SiN thickness are varied. With the increase of the Al mole fraction from 0 to 0.5, the reverse-blocking voltage increases from −510 V to −4500 V for HEMTs using drain FP and optimal SiN passivation thickness, and a high power figure-of-merit of 1.171 GW/cm2 is achieved. AlGaN channel HEMTs with Al mole fraction demonstrate great potential for power applications.

With the propelling high capacity demands, passive optical networks (PONs) are getting extra consideration nowadays. Problem: Burst blocking in wavelength division multiplexed (WDM) PON system increase with the contention period > burst time. Motivation: In the absence of optical random memory in optical communication networks, contention resolution using temporal delays is prominent work and can be accomplished using Fiber temporal delay paths. Burst blocking becomes high in the network at larger contention period such as time between two bursts is larger. Methods: Therefore, in this work, a 40 Gbps × 10 WDM channels based PON system with 50 GHz channel spacing over 20 km is investigated by incorporating switches, switch controller, buffers and Fiber temporal delay paths to decrease the bursts blocking in the system. In order to assign delay to bursts, an algorithm is proposed and calculated amount of delay are assigned to demanding wavelengths for bursts which inturn decrease the blocking. Analysis: Proposed WDM-PON system is simulated in the simulation tool and investigated for different FTD delays, burst loss probability, burst arrival rate, buffering delay and performance is also analyzed in terms of log BER. Results: Bursts blocking probability increases with the increase in burst arrival rate, lesser buffering delays, and more no. of input ports. Further investigation reveals that higher extinction ratios can provide better log BER.

Reward-evoked dopamine transients are well established as prediction errors. However, the central tenet of temporal difference accounts—that similar transients evoked by reward-predictive cues also function as errors—remains untested. In the present communication we addressed this by showing that optogenetically shunting dopamine activity at the start of a reward-predicting cue prevents second-order conditioning without affecting blocking. These results indicate that cue-evoked transients function as temporal-difference prediction errors rather than reward predictions. Maes et al. use second-order conditioning, blocking and optogenetic inhibition to show that cue-evoked dopamine transients function as temporal-difference prediction errors rather than reward predictions.

Precipitation over southeastern Lake Baikal features a significant decreasing trend in July and August over 1979-2018 and is closely related to blocking occurrence over central Siberia (45°–70°N, 75°–115°E). This study investigates the formation and maintenance of anticyclonic and cyclonic wave-breaking (AWB and CWB) blocking events and their climate impacts on precipitation in the southeastern Lake Baikal area. Both AWB and CWB blocking events are characterized by a cold trough deepening from the sub-Arctic region and a ridge amplifying toward its north over central Siberia, as well as an evident Rossby wave train over midlatitude Eurasia. For AWB blocking events, the ridge and trough pair tilts clockwise and the wave train exhibits a zonal distribution. In contrast, ridge and trough pair associated with CWB blocking events leans anticlockwise with larger-scale, meridional, and more anisotropic signatures. Moreover, the incoming Rossby wave energy associated with CWB blocking events is more evident than for AWB blocking events. Therefore, CWB blocking events are more persistent. AWB blocking events produce more extensive and persistent precipitation over the southeastern Lake Baikal area than CWB blocking events, in which moderate above-normal rainfall is seen in the decaying periods of blockings. A significant decreasing trend is found in terms of AWB blocking occurrence over central Siberia, which may contribute to the downward trend of precipitation over southeastern Lake Baikal.

We assess the impact of split-flow blocking in the Australian region on global ocean wind waves using 30 years of high-resolution wave data from the CAWCR wave model hindcast. Statistically significant anomalies in significant wave height (Hs), peak wave period (Tp) and zonal wave energy flux (CgE) are found to covary with local variations in surface zonal wind induced by blocking at 140° E. Strong negative anomalies in these wave fields highlight the role of blocking in promoting calm wave conditions around the Australian coast. A relatively weak but notable remote signal also appears in the Northern Hemisphere extratropics, suggesting a link to the Australian region via tropical forcing. The occurrence of daily low (below the 5th percentile) and high (above the 95th percentile) wave conditions also varies contemporaneously with blocking at 140° E. Considering the ability of global circulation model forecasts to skilfully predict the blocking index out to at least 2 weeks lead time, our results point to blocking as a possible source of predictable wind-wave variability from sub-weekly to seasonal timescales.

Typical blocking indices in longitude or both longitude and latitude are compared to demonstrate: (1) the central blocking latitude (CBL) should be any of 40–80° N; (2) reversals of meridional gradients in absolute fields (ABS) about specified CBLs or in combination with time anomalies exceeding a threshold missed blocking patterns or misidentified non-blocking structures. Blocking highs are identified by a new Eddy-ABS index. A large-scale high is represented by a local maximum of zonal eddy anomalies, its immediately surrounding points and subsequent contiguous grids with decreasing anomalies but exceeding the 75th percentile. A high with any ABS reversal is an instantaneous blocking (IB). Maximum overlapping IBs become quasi-stationary when moving less than 10° longitudes per day. Four and more quasi-stationary IBs form a blocking event (BE). This unified index has identified IBs and BEs at vertical levels in the Northern (NH) and Southern Hemispheres (SH) during different seasons. In the NH, BEs exhibit strong seasonality, geographical preference and quasi-barotropicity. The lifetime, maximum intensity, impact area, and moving speed have a log-linear, log-normal, log-normal, and normal distribution, respectively. These features occur similarly in the SH, except for very small occurrences at 200 hPa in JJA and a normal distribution for the maximum intensity. Properties other than the moving speed significantly correlate with the maximum intensity in both hemispheres. The missing and misidentification issues are reasonably well resolved by this new index.

Recent years have witnessed significant interest in biodegradable and transparent ultraviolet (UV) protecting films from renewable resources. In the present paper, preparation, characterization and evaluation of UV radiation blocking capability of transparent and flexible cellulose nano fibril (CNF)–poly vinyl alcohol (PVA) films are described. Synthesized films exhibited good transparency in the visible region and UV blocking ability. Addition of plasmonic silver (~ 22 nm) to the films lead to complete blocking of UV radiations. Synthesized films were highly stable for a long exposure to intense sunlight. The defined methods show a straightforward procedure for the fabrication of environment friendly UV-radiation blocking films for industrial/commercial/textile applications.

This study statistically examines the role of atmospheric blocking as a precursor of major seismic events. Atmospheric blocking archive and earthquake databases for the Middle East region are compiled for 2000–2013. Correlations between atmospheric blocking events and seismicity are examined based on defined seismo-climatic index (SCI) based on variations of earthquake frequency and magnitude before and after blocking events. Limiting the SCI index to values > 6, 16 out of 26 major earthquakes (M > 6), i.e. 62%, are shown to have occurred within 14 days after blocking events over their respective epicentral regions. The correlation between blocking events and subsequent seismicity falls into a range of 0.694–0.803. Additional blocking-related atmospheric anomalies such as cyclogenesis, cloud coverage, and anomalous rainfall prior to major earthquakes can be understood as processes that take place in the Earth’s crust and at the ground-to-air interface as a result of the stress activation of positive hole charge carriers at depth, in the hypocentral rock volume, and their rapid migration to the Earth’s surface. Hence, atmospheric blocking events in a seismically active region may be categorized as an earthquake precursory phenomenon.

Atmospheric blocking represents an important aspect of the mid-latitude weather variability, but the different processes contributing to its formation and maintenance are not yet fully understood. This study investigates the role that diabatic processes, in particular the release of latent heating in strongly ascending airstreams, play in the dynamics and spatio-temporal variability of blocking in a detailed 38-year global climatological analysis. The results show that the formation and (re-)intensification of blocking are often preceded by latent heating connected to upstream baroclinic developments. While the importance of latent heating varies considerably between individual blocking events and different regions, in particular between ocean and continents, latent heating is generally most important during onset and in more intense and larger blocks. The episodic nature of latent heating during the blocking life cycle, associated with a series of transient cyclones approaching the blocking, can contribute to both the high- (fast onset and fluctuation in intensity and size) and low-frequency (maintenance and quasi-stationarity during maturation phase) properties of blocking anticyclones and provide the required flow amplification in addition to dry-dynamical interaction between synoptic eddies and blocking. This amplification results from a combination of the direct injection of anticyclonic air into the upper-troposphere within cross-isentropic ascending airstreams, setting up large-scale anticyclonic PV anomalies, and the advection of PV by the enhanced divergent outflow at the tropopause (indirect effect). This divergent outflow on the western flank of the blocking anticyclone interacts with the upper-level PV gradient and leads to a westward amplification of the ridge, diminishing the tendency for dissipation and the eastward advection by the background flow, thus contributing to blocking stationarity. Taking into account such diabatic mechanisms in blocking dynamics will be important to improve predictions of blocking and assess future changes in the extratropical large-scale circulation.

In this paper, we have developed an efficient channel assignment scheme using fractional guard channel for utilizing the limited radio recourses efficiently and seamlessly by providing buffer for good-quality signal calls to improve the quality of service. Two models are proposed to prioritize good-quality handoff calls over poor-quality calls. The expressions for blocking probability, call dropped probability of handoff calls, utilization of channels and buffer are obtained for a cellular radio network. Numerical simulation results for both the models illustrate the impact of different parameters on the key performance measures.

Firms use patents for blocking competitors’ innovation activities. Offensive blocking is a practice whereby firms patent alternatives of a focal invention preempting technological substitutes produced by competitors. Defensive blocking entails the creation of patent portfolios that block technologies in order to increase competitors’ willingness to trade patents. This paper examines the private value of both patent blocking strategies with the use of a novel measure of the offensive and defensive “blocking power” of patent portfolios. We show that both strategies increase firms’ market value. In discrete (complex) product industries, however, only offensive (defensive) patent blocking is associated with higher value.

The relationship between blocking events and mean precipitation frequency (MPF) was investigated in this work for Turkey during 1977–2016. The overall MPF for the examined stations during blocked days (nonblocked days) fluctuated between 0.15 and 0.43 (0.12 and 0.38). The ratio of MPF during the blocked days to nonblocked days ranges between 12 and 38%. During the winter season, the country has higher MPF values during blocked days. The greatest ratio of MPF values during blocked days to nonblocked days is observed in summer due to smaller values of MPF occurring during this season overall. Higher MPF occurs when the event center was located between 0o and 30o E (mean 0.27, range 0.17–0.51). There is no relationship between blocking duration and MPF for all seasons. There is a positive relationship between blocking intensity and MPF during summer (CC = 0.35, significant at the 95% level) and fall (CC = 0.43, significant at the 95% level). The relationship between blocking longitudinal extent and MPF is significant at the 95% confidence level during the summer and fall seasons with correlation coefficients of 0.29 and 0.25, respectively. A composite of the 10 blocking events associated with the largest MPF demonstrated that there is moist advection via westerly flow into Turkey in all seasons. During winter, a greater proportion of these events is observed during the La Nina phase of El Nino Southern Oscillation, but during El Nino in spring and summer. For the blocking case study (31 October to 5 November 2009) associated with the largest MPF, the mean value across the country was 0.73. The mean total precipitation during this period was 63.4 mm.

The CO2 is regarded to be an excellent solvent for miscible flooding. However, it is still facing a main problem which is the high mobility. Microbubbles with their unique characters offer some advantages for CO2 EOR application. Different pore throat size filters were used to generate different dominant sizes of microbubbles that were injected into sandpacks under tertiary condition. Microscopic analysis was carried out to visualize the presence, stability and behavior of microbubbles inside the solution and porous media. The microbubbles with a dominant size of 10–50 µm showed additional 26.38% of oil recovery, showing their advantages over a larger dominant size of microbubbles up to 5.28% of oil recovery. The injection with larger microbubbles with a dominant size of 70–150 µm showed 27.5% of higher injection pressure than with a smaller dominant size of microbubbles, showing their advantage in gas blocking ability. In the heterogeneous porous media experiment, the recovery volume ratio between low- and high-permeability sandpacks was increased from 1:57 during water flooding to 1:4 during the CO2 microbubble injection with 74.65% of additional recovery from a low-permeability zone, showing the microbubble gas blocking capability to change the flow pattern inside heterogeneous porous media.

Due to the development of IT technology, harmful multimedia contents are spreading out. In addition, obscene and violent contents have a negative impact on children. Therefore, in this paper, we propose a multimodal approach for blocking obscene and violent video contents. Within this approach, there are two modules each detects obsceneness and violence. In the obsceneness module, there is a model that detects obsceneness based on adult and racy score. In the violence module, there are two models for detecting violence: one is the blood detection model using RGB region and the other is motion extraction model for observation that violent actions have larger magnitude and direction change. Through result of these three models, this approach judges whether or not the content is harmful. This can contribute to the blocking obscene and violent contents that are distributed indiscriminately.

Energy transmission lines play a more important role in power transferring from producer to consumers. Energy transmission lines should be protected from the fault and the faults should be cleared as soon as possible time. Distance relays due to their simplicity application are widely used for protection of power transmission lines. When a power swing occurs in the power system the distance relay may mal-operate during this phenomenon. In order to prevent this, the power swing blocking function is used in distance relays. In this paper, a new method based on the rate of change of the instantaneous frequency is proposed. This method has been tested practically in a standard two-area network and its applicability for detection of different types of faults is presented. One of the features of this method is low computing and simplicity in implementation, independent of network type, unnecessarily complicated setting, high impedance fault detection, and unstable power swing detection. Also, the proposed method is compared with the conventional industrial method and it has been shown that the proposed method has better performance.

Wavelength division multiplexing-based networks suffer from blocking probability due to wavelength contention resolution. Such a problem can even be worth when the advanced coherently modulation formats such as M-array quadrature amplitude modulation is used to increase the channel capacity beyond 100 Gbit/s. This paper presents theoretical study of cascaded sum frequency generation and difference frequency generation based tunable wavelength conversion in a periodically poled lithium niobate waveguide as a trivial solution to the wavelength blocking problem when advanced signal modulation formats are considered. It is shown numerically that wavelength conversion of single channel up to 1 Tbit/s would be possible with a 3 cm long wavelength converter.

Governments need to think twice before they suppress messages related to COVID-19. Governments need to think twice before they suppress messages related to COVID-19.

The blocking phenomenon has received considerable attention from many researchers due to its impact on weather and human life. This paper aims to provide a new blocking definition with applicability to observations. The daily National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data for the Northern Hemisphere of geopotential height at a level of 500 hPa during the summer season of 2010 was used in this study. Additionally, observations for several meteorological variables over the Northern Hemisphere, including Europe, through that period were collected and analyzed. By applying the new blocking definition over the Northern Hemisphere, three blocking events persisted over Europe for a duration of 5, 17 and 36 days. The exact total days of blocking events that persisted over Europe was 58 days in the summer of 2010. Moreover, during the blocking events in the summer of 2010 abnormal weather conditions, extremely hot, dry and increased pressure over Europe observed.

A laminate aimed to be used in high frequency CCL is prepared by introducing free volume into employing adding HBP blocking by hexanoic acid (HBP-C6). The effects of HBP-C6 on the electrical properties is analyzed. The results indicated the permittivity (Dk) of laminated is 4.03 and the dielectric loss (Df) is 0.00018 at the frequency of 107 Hz, when the HBP-C6 content is 15 wt%. The breakdown strength of the laminate is 28.62 kV/mm, the volume resistivity of composites is 3.25 × 1014 Ω m, which shows a good insulation property. The mechanical, moisture absorption rate, peel strength and flame retardant results also give the application possibility on high frequency CCL.

IoT (Internet of Things) security has become a severe yet not well solved problem attracting increasing research attention as well as industrial concerns. Location-based access control approaches, such as Wi-Fi geo-fencing, promise to fulfill the needs of preventing unauthorized access to IoT systems. We propose a crowdsourcing method for location aware security access control, namely LaSa, which is able to confine wireless network access inside certain physical areas only using a single commercial Access Point (AP). Specifically, LaSa detects whether a user enters or exits a room by discovering and recognizing the unique signal patterns. It combines the Received Signal Strength (RSS), Channel State Information (CSI), and coarse Angle of Arrival (AoA) data to improve the accuracy of user classification for accessing the wireless network. Real-world experimental results show that LaSa can achieve a 97.0% accuracy of identification of unauthorized users while maintaining a low false blocking rate of authorized users as low as 3.3%. LaSa is designed to be straightforward for integration with commercial APs and deployment to home and business Wi-Fi environments.

The purpose of this chapter is to provide a brief review of the literature around the relationship between the use of neuromuscular blocking drugs and subsequent postoperative pulmonary complications. A recent series of retrospective studies evaluating the use of neuromuscular blocking agents and postoperative complications have demonstrated growing evidence for a clear relationship between the use of the agents and downstream complications. The frequency of postoperative respiratory problems seems to be mitigated to some degree through the appropriate use of reversal agents. Care should be exercised when administering neuromuscular blocking agents during surgical procedures. Appropriate monitoring of neuromuscular transmission should be used along with a strategy to provide adequate reversal at the end of the surgical procedure.

The notorious party drug may act as an antidepressant by blocking neural bursts in a little-understood brain region that may drive depression

Cognitive Radio Network is an emerging popular wireless network, designed for efficient spectrum utilization. It enables unlicensed users to access the unused portion of the licensed spectrum opportunistically. The major challenge is to share the unused portion of the spectrum efficiently to the unlicensed users. Channel aggregation is an interesting approach by which channels can be grouped and allocated to unlicensed users. A combined Round Robin Priority (RRP) scheduling algorithm is proposed by which the starvation of low priority SUs are minimized and QoS parameters are better compared to the traditional static and dynamic channel aggregation method. Fuzzy Inference System is used to evaluate the priority of the Secondary User. The QoS parameters utilized for comparison are spectrum utilization, capacity of the secondary network, delay, blocking probability and forced termination probability.