The concept of elementary siphons Petri nets is first proposed in our previous work. However, their definitions can cause confusion when there exist weakly independent a net. In this correspondence, we redefine and show the significance improvement

The importance of siphons is well recognised in the analysis and control deadlocks Petri nets. Deadlock prevention problems are considered for S4PR, a class generalised nets, that can model large flexible manufacturing systems (FMS). Siphons plant net divided into elementary dependent ones. achieved by adding monitors (control places) to make every siphon satisfy maximal controlled-siphon property. Conditions developed under which maximally controlled when its so. max-controllability ensured...

Abstract We investigate the latitudinal and longitudinal variations of thermospheric nitric oxide (NO) cooling rate from 2005 to 2016. compare maximum NO its altitude measurements by Sounding Atmosphere using Broadband Emission Radiometry (SABER) instrument on National Aeronautics Space Administration (NASA)'s TIMED (Thermosphere‐Ionosphere‐Mesosphere Energetics Dynamics) satellite simulations Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM). In both data model,...

Abstract Observations from lidars and satellites have shown that large neutral temperature increases decreases occur in the middle low latitudes of mesosphere lower thermosphere region during geomagnetic storms. Here we undertake first‐principles simulations responses to storms using Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model elucidate nature causes these changes. Temperature variations were not uniform; instead, nighttime temperatures changed earlier than...

Abstract The behaviors of thermospheric nitric oxide (NO) cooling during the 15 May 2005 intense geomagnetic storm are studied using measurements by Sounding Atmosphere Broadband Emission Radiometry instrument on board Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics satellite simulations Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model. was most ( Dst = −247 nT) with a short rapid main phase long‐lasting recovery (more than 3 days). NO responded globally to within...

Abstract Joule heating and radiative cooling usually play key roles in high‐latitude thermospheric temperature changes during geomagnetic storms. In the mesosphere lower thermosphere (MLT), however, causes of storm‐time at high latitudes are still elusive. Here, we elucidate nature mechanisms MLT variations 10 September 2005 storm by diagnostically analyzing thermodynamics Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIMEGCM) simulations. storm's initial main...

We selected three superstorms (disturbance storm time [Dst] index less than −350 nT) of 2003–04 to study the thermospheric energy budget with a particular emphasis on cooling emission by nitric oxide via wavelength 5.3 μ m. The radiative data are obtained from Sounding Atmosphere Broadband Emission Radiometry (SABER) instrument onboard Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite thermosphere ionosphere electrodynamic general circulation model (TIEGCM)...

Post‐sunrise intense ionospheric irregularities at low to mid‐latitudes are reported for the first time. A method based on spaced‐receiver technique is proposed estimate apparent drift velocity of by using correlation slant total electron content (TEC) from 3 GPS receivers. The were detected 23∼45°N Earth Observation Network (GEONET) Japan ∼0455 LT ∼1051 21 March 2001 during recovery phase magnetic storm. At corresponding time spread F was observed with ionosondes located meridionally...

Abstract In this study, the Empirical Mode Decomposition algorithm (EMD) and Long Short Term Memory neural network (LSTM) are combined into an EMD‐LSTM model, to predict variation of >2 MeV electron fluxes 1 day ahead. Input parameters include Pc5 power, AP, AE, Kp, >0.6 MeV, historical flux values, used for predictions. All time resolution daily integral values. As compared prediction results model with other classical models, show that ahead efficiency possesses a 0.80, highest can...

Cyber-physical systems have emerged as a key technology in the development of distributed and autonomous large scale systems. However, one their undesirable side effects is fact that they are particularly exposed to cyber attacks carried out by malicious intruders. Therefore, efficient strategies for security high demand. In this paper, we consider issue attack detection framework partially observable discrete event modeled finite automata. We assume observation produced plant can be...

Deadlocks are a highly undesired situation in automated production systems including flexible manufacturing systems. Based on Petri net formalism, novel deadlock prevention policy is proposed for class of nets, S3PR, by using an MIP-based detection method and elementary siphons nets. Deadlock achieved synthesising set monitors that added to the plant model. The concept dominated transitions proposed, which output arcs led. computed according model, found established algorithm literature....

For a system of sequential systems with shared resources (S4R), typical class Petri net models flexible manufacturing (FMS), current deadly marked siphon (DMS) detection approaches based on mixed integer programming (MIP) cannot detect siphons that cause livelocks in systems. Thus deadlock-free be further controlled. Moreover, most these methods obtain minimal DMS directly. This study proposes the concept extended (EDMS) basis max″-controllability condition siphons. Accordingly, more general...

In the presence of multiple primary users (PUs), exact outage probability partial amplify-and-forward (AF) relay selection in spectrum-sharing networks is investigated. To gain more insight, a simple and accurate approximation also derived high signal-to-noise ratio (SNR) region. It shown that, at SNR, affected only by channel between relay-destination links to relay-PU links, regardless number relays. Moreover, when PUs are present, it causes performance degradation on secondary system....

The high-speed solar winds stream (HSSWS) generated by coronal hole can produce large interplanetary magnetic field magnitude oscillations, leading to high latitude geomagnetic disturbances, and ionospheric responses as well. This paper has analyzed the global total electron content (TEC) rate of TEC index (ROTI) during speed occurred from 23 29 August, 2010. Ground Global Navigation Satellite System (GNSS) network was mainly used investigate ionosphere ROTI behaviors. It revealed that...

The variations of neutral temperature in the mesosphere and lower thermosphere (MLT) region, during 7–8 September 2017 intense geomagnetic storm, are studied using observations by Sounding Atmosphere Broadband Emission Radiometry (SABER) instrument onboard Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite. They also simulations Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIMEGCM). data cover altitudes from 80 km to 110 between 83° N...

Siphons are special structures of a Petri net. Their number grows exponentially with the net size. Hence, traditional siphon-based deadlock control policies have two problems, that is, generating very structurally complex supervisory controllers and requiring intractable computation efforts. This paper intends to use newly proposed concept, elementary siphons, mixed integer programming (MIP) method design simple reduce computational burden. is applicable class nets, System Simple Sequential...

Abstract The nitric oxide (NO) 5.3 μm radiative emission is the dominating and most efficient cooling agent in thermosphere above 100 km. NO an important parameter, particularly during geomagnetic storm events, to quantify energy budget within magnetosphere‐ionosphere‐thermosphere system. We utilize TIMED (Thermosphere‐Ionosphere‐Mesosphere Energetics Dynamics)/SABER (Sounding of Atmosphere using Broadband Emission Radiometry) observations investigate storm‐time hemispheric asymmetry...

Using observations by the SABER (Sounding of Atmosphere using Broadband Emission Radiometry) instrument on board TIMED (Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics) satellite simulations TIEGCM (Thermosphere-Ionosphere-Electrodynamics General Circulation Model), we investigate daytime variations thermospheric nitric oxide (NO) cooling during geomagnetic storm 6 May 2015. The was minor, as minimum Dst −28 nT, maximum Kp 5+ AE 1259 nT. However, significant enhancements peak NO...

For the purpose of deadlock control, siphons in a Petri net (PN) can be divided into elementary and dependent ones; latter further distinguished by strongly weakly (WDS). The computation PN is essential but expensive since complete siphon enumeration needed. results reported literature show that control WDS quite conservative. Li et al. present two open problems. First, for what kinds PN, we definitely find set such no derived? Secondly, could develop an algorithm to minimise number net? aim...

In cooperative wireless networks, relay selection plays a significant role in the system performance. this paper, with presence of interferences, we firstly propose two protocols according to forms interferences. Then considering that interference caused by selected has an effect on other transmissions, threshold based protocol is proposed select one best forwarding message, where below than predetermined threshold. Furthermore, protocols, all relays and destination are subject interferences...

Abstract The angular width of a coronal mass ejection (CME) is an important factor in determining whether the corresponding interplanetary CME (ICME) and its preceding shock will reach Earth. However, there have been very few studies decisive factors CME’s width. In this study, we use three-dimensional (3D) CMEs obtained from Graduated Cylindrical Shell model based on observations Solar Terrestrial Relations Observatory ( STEREO ) to study relations between 3D characteristics source region....

Abstract The National Center for Atmospheric Research Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM) is a three‐dimensional physics model of the Earth's upper atmosphere. Using eigen analysis, hourly NO infrared radiative flux (NOF) during 2002–2015 obtained from TIEGCM simulations are decomposed into four empirical orthogonal functions (EOFs). first mode variability significantly associated with Kp and F10.7, implying that geomagnetic activity solar extreme...