Ingress Point Research Articles

Evaluating portable air cleaner effectiveness in residential settings to reduce exposures to biomass smoke resulting from prescribed burns.

Prescribed burning is the most common method employed to reduce fuel loads in flammable landscapes. This practice is designed to reduce the hazard associated with uncontrolled bushfires. Prescribed burns are frequently conducted close to residential areas, and the associated smoke impacts can adversely affect community health. Particulate matter is the predominant pollutant within the smoke and is strongly and consistently linked with adverse health effects. Outdoor smoke readily infiltrates buildings and reduces the quality of indoor air. Portable air cleaners containing high-efficiency particulate air (HEPA) filters are a promising indoor air quality intervention for reducing outdoor smoke exposure. We provided 10 homes from semirural regions of Victoria, Australia, with HEPA cleaners and conducted continuous monitoring of indoor and outdoor fine particulate matter (PM2.5) for 2-4 weeks during prescribed burning periods. We calculated the potential improvements to indoor air quality when operating a HEPA cleaner during a smoke episode. Ventilation measures were conducted to identify points of smoke ingress and housing characteristics that could lead to higher infiltration rates. Depending on the house, the use of HEPA cleaners resulted in a reduction in indoor PM2.5 concentrations of 30-74%. HEPA cleaners have the potential to substantially improve indoor air quality during episodic smoke episodes.

Abstract 5787: Structure-function mapping of DHODH shows deviations in protein structure

Abstract Dihydroorotate dehydrogenase (DHODH) is a CoQ-dependent enzyme that converts dihydroorotate to orotate in the de novo pyrimidine biosynthesis pathway. Multiple structures of DHODH in complex with various small molecule inhibitors have been solved that indicate that DHODH inhibitors bind in the CoQ binding tunnel of DHODH and act as competitive inhibitors of CoQ. We performed saturating mutagenesis screens to identify mutations in DHODH that confer resistance to brequinar and BAY2402234, two highly potent DHODH inhibitors. As expected, many of the resistance mutations localized to the drug/CoQ-binding tunnel of the enzyme. Among the top-scoring drug-binding-domain mutants in both the brequinar and BAY2402234 screens were substitutions A58H and A58T. In silico analysis predicted that A58H should impair DHODH binding to both brequinar and BAY2402234. However, A58T was predicted to only impair binding of DHODH to brequinar. We expressed the mutants in a DHODH inhibitor sensitive cell line and confirmed that they both confer resistance to brequinar and BAY2402234, and we then assessed the ability of the mutants to bind drug by cellular thermal shift assay (CETSA). We found that, as predicted, DHODH A58H did not bind brequinar or BAY2402234. However, to our surprise, we detected binding of both brequinar and BAY2402234 to DHODH A58T. We generated recombinant DHODH A58T and confirmed that the purified protein was enzymatically active and strongly drug-resistant by DCIP assay and then assessed binding of the mutant protein to brequinar and BAY2402234 by thermal shift assay (TSA). Consistent with our CETSA results, recombinant DHODH A58T bound both brequinar and BAY2402234 in vitro. These results suggested that DHODH A58T can simultaneously bind drug and CoQ. However, previously reported DHODH structures indicated that the drug/CoQ binding tunnel is quite narrow and rigid. To determine whether the structure of catalytically-active DHODH is more flexible than inhibitor-bound catalytically-inactive DHODH, we co-crystallized wild-type DHODH with decylubiquinone (DCU), a CoQ analog that can act as a DHODH co-substrate in vitro. We found that the structure of DCU-bound DHODH differs from previously published DHODH structures in two important ways: (1) there appears to be a second point of ingress into the active site of DHODH next to the CoQ tunnel that may be able to accommodate a highly non-polar molecule such as CoQ/DCU and (2) the ‘flap’ covering the DHO/orotate ingress/egress region of DHODH, which is ‘closed’ in inhibitor-bound DHODH, is ‘open’ in DCU-bound DHODH. We are currently working to solve the crystal structure of DHODH A58T bound to inhibitor and DCU to ask if DCU can access the active site of DHODH through an alternative hydrophobic tunnel and if DHODH A58T remains in the ‘open’ configuration when bound to drug. Citation Format: Ruchika Pokhriyal, Laura Evans, Hyuk-Soo Seo, Jillian K. O'Neil, Betty Rouaisnel, Atanas Kamburov, Judith Guenther, Stefan Gradl, Haribabu Arthanari, Sven Christian, Xiaoping Yang, Sirano Dhe-Paganon, Julie-Aurore Losman. Structure-function mapping of DHODH shows deviations in protein structure [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5787.

Hidden Markov model for spatial analysis of three-dimensional mineralization distribution: Insights into magma flow and mineral exploration targets in the Jinchuan Ni-Cu-(PGE) sulfide deposit, China

The spatial distribution of mineralization includes significant clues about the magma/fluid flow process for ore formation. However, given the complex nature of the ore-forming process and its weak signature in the mineralization data, revealing the magma/fluid flow process in their mineralization footprint presents a considerable challenge. In this paper, we present a hidden Markov model (HMM) for the analysis of three-dimensional (3D) spatial distribution of mineralization. The HMM assumes the magma flow is a Markov process that is “hidden” in the “observable” mineralization features. Under this setting, the HMM quantifies the states of magma flow and links them as a whole in a probabilistic manner. This allows for the comprehensive combination of mineralization information, facilitating holistic inference of magma flow hidden in the mineralization signal. Based on the maximum likelihood principle, the magma trajectories and the associated injection points are inferred from the HMM. The proposed model is applied to spatial analysis of the mineralization in the world-class Jinchuan Ni-Cu-(PGE) magmatic sulfide deposit in NW China. Based on the 3D mineralization data interpolated from drill assays, the HMM infers magma trajectories and the associated injection points at Jinchuan, which indicate the Jinchuan deposit was formed by a multiple magma conduit system that comprises four independent injection points of magma ingress. According to the identified magma trajectories and injection points, four sites beneath the injection points and along the extension of magma trajectories are considered promising for future mineral exploration. With the insights gained from this case study, the proposed HMM can serve as an effective tool in the exploration information system to unveil magma/fluid flow history and guide exploration efforts toward concealed, deep-seated mineralization.

Postdigital health practices: new directions in medical humanities

Digitalisation has changed the way we understand and practice health. The recent pandemic has accelerated some of the developments in digital health and brought about modifications in public access to...

Advancing Urban Wastewater Management: Optimizing Sewer Performance through Innovative Material Selection for the Armlet with a Wet Circuit Measurement System

Rainwater infiltration presents substantial challenges for urban wastewater management systems. This article delves into enhancing the quality of wastewater systems by proposing a novel device designed to tackle this issue comprehensively. The focal point of our research revolves around the conceptualization, construction, rigorous testing, and the potential multifaceted applications of this innovative wastewater device. Our study is dedicated to assessing the viability of a cutting-edge apparatus that empowers municipal entities in swiftly identifying rainwater ingress points within channels during precipitation events. Our findings vividly showcase the device’s remarkable capability to directly measure moisture levels along the channel’s path, eliminating the arduous need for manual data input, extensive data collection, and intricate water analysis procedures. To ensure the seamless flow of both sewage and water within the sewer channel, the use of a relatively slender strap is conventionally favored. However, factoring in the requisite structural robustness, we recommend a minimum thickness of 4 mm for 3D printing applications. For instances where maintaining the channel’s cross-sectional area integrity is paramount, opting for an armlet with a wet circuit measurement thickness of up to 7 mm is vital. In the realm of material selection, our investigation advocates for the utilization of PC/ABS (polycarbonate/Acrylonitrile Butadiene Styrene), ABS, ASA (Acrylonitrile Styrene Acrylate), or HIPS (High Impact Polystyrene) for strap housing. For sewer diameters surpassing 315 mm, the application of thin-walled PVC (Poly Vinyl Chloride) emerges as a practical recommendation. Notably, the incorporation of PVC flat bars is discouraged, as their presence might potentially hinder the fluidity of sewage flow, thereby compromising the precision of wet circuit measurements. The pivotal innovation lies in the armlet with a wet circuit measurement system, harboring immense potential for broad-scale integration across municipal facilities. This solution emerges as a streamlined and efficient strategy, offering a comprehensive avenue for continuously monitoring, fine-tuning, and optimizing the structural soundness and operational efficacy of sewer systems.

Edge Strategies in Industry: Overview and Challenges

This paper discusses some details from the 2020 NetSoft conference DEP panel. This panel consisted of industry experts, and as such the perspective presented here is biased with an industry view of Edge Computing. In sharing this discussion and further expanding on the discussion in this paper the hope is to provide the research community with guidance on opportunities to advance and possibly accelerate the rate of Edge adoption (Tiwari et al., 2021). There is no avoiding the Edge discussion; today in industry Communication Service Providers see this is an avenue to monetize their 5G investment, the cloud providers, also known as the `hyperscalers', see this as providing an ingress point into new markets, and finally enterprises themselves see this as an opportunity to modernize and gain business advantages through insights and better process management. Two U.S. based mobile network operators have edge portfolios (AT&T Edge Solutions, 2021 and Verizon, 2021). Many examples exist around the globe with other network service providers, an exhaustive list would consume this paper. In addition, 2020 saw Microsoft acquire two Independent Software Vendors (ISV's), Metaswitch and Affirmed. This clearly is intended to bring edge capability into their Azure product line.

LCDA: Lightweight Continuous Device-to-Device Authentication for a Zero Trust Architecture (ZTA)

Continuous Authentication (CA) has been proposed as a potential solution to counter complex cybersecurity threats posed against conventional static authentication mechanisms that merely authenticate at ingress points of a platform. However, widely researched CA mechanisms that rely on user’s behavioural characteristics cannot be extended to continuously authenticate Internet of Things (IoT) devices. Challenges are exacerbated with the increased adoption of device-to-device (d2d) communication in critical infrastructures. Existing d2d authentication protocols proposed in the literature are either prone to subversion or are computationally infeasible to be deployed on constrained IoT devices. In view of these challenges, we propose a novel, Lightweight Continuous Device-to-Device Authentication (LCDA) protocol that leverages communication channel properties and a tunable mathematical function to generate dynamically changing session keys for continuous device authentication. Our extensive informal and formal analysis confirms the efficacy of the proposed LCDA protocol in terms of its resilience to known attack vectors, thereby demonstrating its strong potential for deployment in critical and resource-constrained scenarios for secure d2d communication.

WASP-117 b: An Eccentric Hot Saturn as a Future Complex Chemistry Laboratory

Abstract We present spectral analysis of the transiting Saturn-mass planet WASP-117 b, observed with the G141 grism of the Hubble Space Telescope's (HST) Wide Field Camera 3. We reduce and fit the extracted spectrum from the raw transmission data using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available analysis suite TauREx 3.0. We detect water vapor alongside a layer of fully opaque cloud, retrieving a terminator temperature of K. In order to quantify the statistical significance of this detection, we employ the atmospheric detectability index (ADI), deriving a value of ADI = 2.30, which provides positive but not strong evidence against the flat-line model. Due to the eccentric orbit of WASP-117 b, it is likely that chemical and mixing timescales oscillate throughout orbit due to the changing temperature, possibly allowing warmer chemistry to remain visible as the planet begins transit, despite the proximity of its point of ingress to apastron. We present simulated spectra of the planet as would be observed by the future space missions such as the Atmospheric Remote-sensing Infrared Exoplanet Large-survey and the James Webb Space Telescope and show that, despite not being able to probe such chemistry with current HST data, these observatories should make it possible in the not too distant future.

Seasonal prevalence and histopathology of Beauveria bassiana infecting larvae of the leopard moth, Zeuzera pyrina L. (Lepidoptera: Cossidae)

The natural epizootic potential of the fungus, Beauveria bassiana, against larvae of the leopard moth, Zeuzera pyrina L. (Lepidoptera: Cossidae) was investigated under natural conditions in two different locations for two seasons (2015–2016 and 2016–2017) in Rasheed, Behiara Governorate, Egypt. In an orchard, located in the old cultivated land, Beauveria infected 1.9–5.6% of larvae of Z. pyrina in autumn (September to November), increased to 3.4–7.2% in winter (December to February). The infection did not exceed 3.1% in spring (March to May), and no infection was recorded in summer (June to August). While in an olive farm, located in a newly reclaimed land, in both seasons of survey, no infections were recorded from May to September, while in winter, the epizootics ranged from 1.4–3.1%, from 0.4 to 1.3% in spring, and from 0.3 to 2.1% in autumn. Histopathological analysis revealed that Beauveria most commonly penetrated larvae directly through the intersegmental integument and the first symptoms were observed 3 to 4 days later. Hyphae radiated inward from the point of ingress and the fungus developed sparsely within the body cavity prior to the death of the larva. Hyphal bodies were concentrated around the point of ingress, but some were found at distance from this site. Only in the vicinity of penetration, the hypodermis showed signs of histolysis. The saprophytic phase developed rapidly and the fungus invaded all internal organs. The conidiophores seemed to rupture the cuticle by mechanical pressure and emerged all over the host cadaver, with sporulation occurring 48 h later. Pathological changes in the hemolymph appeared to be the primary cause of larval mortality.

JCN October special issue on IoT security and privacy

The emerging IoT (Internet of Things) paradigm aims to connect all kinds of different physical objects together and make them accessible from the Internet, with advanced sensing, actuation, communications, and networking technologies. IoT systems vary in type, scale, and function. They range from Internet of Vehicles, to Industrial Internet of Things, to Internet of Battlefield Things and Internet of Medical Things. Gartner predicts that tens of billions of IoT devices will be in use in the near future. Many low-cost IoT devices have little processing power or storage capacity, resulting in poor built-in security capabilities. This allows these devices to be used as ingress points to access the broader IT or critical infrastructure. Because of the expanded attack surface, IoT security and privacy has become a pressing issue. Every threat against the IoT may constitute a more severe threat to the IT or critical infrastructure behind the IoT. Thus, it is imperative to study and understand the security and privacy risks related to IoT and to propose innovative solutions to deal with these risks. This special issue received 16 submitted manuscripts, out of which 7 papers have been accepted for publication. The papers in this special issue will report research advances in IoT Security and Privacy in the following two aspects: Algorithms and Protocols, and Systems and Applications. The papers in the special issue are briefly summarized.

The plant hypersensitive response: concepts, control and consequences.

SummaryThe hypersensitive defence response is found in all higher plants and is characterized by a rapid cell death at the point of pathogen ingress. It is usually associated with pathogen resistance, though, in specific situations, it may have other consequences such as pathogen susceptibility, growth retardation and, over evolutionary timescales, speciation. Due to the potentially severe costs of inappropriate activation, plants employ multiple mechanisms to suppress inappropriate activation of HR and to constrain it after activation. The ubiquity of this response among higher plants despite its costs suggests that it is an extremely effective component of the plant immune system.

A maize polygalacturonase functions as a suppressor of programmed cell death in plants

BackgroundThe hypersensitive defense response (HR) in plants is a fast, localized necrotic response around the point of pathogen ingress. HR is usually triggered by a pathogen recognition event mediated by a nucleotide-binding site, leucine-rich repeat (NLR) protein. The autoactive maize NLR gene Rp1-D21 confers a spontaneous HR response in the absence of pathogen recognition. Previous work identified a set of loci associated with variation in the strength of Rp1-D21-induced HR. A polygalacturonase gene homolog, here termed ZmPGH1, was identified as a possible causal gene at one of these loci on chromosome 7.ResultsExpression of ZmPGH1 inhibited the HR-inducing activity of both Rp1-D21 and that of another autoactive NLR, RPM1(D505V), in a Nicotiana benthamiana transient expression assay system. Overexpression of ZmPGH1 in a transposon insertion line of maize was associated with suppression of chemically-induced programmed cell death and with suppression of HR induced by Rp1-D21 in maize plants grown in the field.ConclusionsZmPGH1 functions as a suppressor of programmed cell death induced by at least two autoactive NLR proteins and by two chemical inducers. These findings deepen our understanding of the control of the HR in plants.

Towards a Better Response: Combining Pareto Ranking and Geostatistics to Model Gender-Based Vulnerability in Rohingya Refugee Settlements in Bangladesh

Introduction:The Rohingya refugee crisis in Bangladesh continues to overburden humanitarian resources and undermine the health and security of over 900,000 people. Spatial, sector-specific information is required to better understand the needs of vulnerable populations, such as women and girls, and to target interventions with improved efficiency and effectiveness.Aim:The aim of this study was to create a gender-based vulnerability index and explore the geospatial and thematic variations in the gender-based vulnerability of Rohingya refugees residing in Bangladesh by utilizing pre-existing, open-source data.Methods:Data sources included remotely-sensed REACH data on humanitarian infrastructure, UN Population Fund resource availability data, and the Needs and Population Monitoring Survey conducted by the International Organization for Migration in October 2017. Gaps in data were addressed through probabilistic interpolation. A vulnerability index was designed through a process of literature review, variable selection and thematic grouping, normalization, and scorecard creation. Pareto ranking was employed to rank sites based on vulnerability scoring. Spatial autocorrelation of vulnerability was analyzed with the Global and Anselin Local Moran’s I applied to both combined vulnerability index rank and disaggregated thematic ranking.Results:Twenty-four percent of settlements were ranked as most vulnerable, with 30 highly vulnerable clusters identified predominantly in the Upazila of Sadar. Five settlements in Dhokkin, Somitipara, and Pahartoli were categorized as less vulnerable outliers amongst highly vulnerable neighboring sites. Security- and health-related variables appear to be the largest drivers of gender-specific vulnerability in Cox’s Bazar. Clusters of low security and education vulnerability measures are shown near the refugee ingress point near Gundum.Discussion:The humanitarian space produces tremendous amounts of data that can be analyzed with spatial statistics to better target research and programmatic intervention. The critical utilization of these data and validation of vulnerability indexes is required to improve the international response to the global refugee crisis.

Reducing Latency in Virtual Machines: Enabling Tactile Internet for Human-Machine Co-Working

Software-defined networking (SDN) and network function virtualization (NFV) processed in multi-access edge computing (MEC) cloud systems have been proposed as critical paradigms for achieving the low latency requirements of the tactile Internet. While virtual network functions (VNFs) allow greater flexibility compared to hardware-based solutions, the VNF abstraction also introduces additional packet processing delays. In this paper, we investigate the practical feasibility of NFV with respect to the tactile Internet latency requirements. We develop, implement, and evaluate Chain-based Low latency VNF ImplemeNtation (CALVIN), a low-latency management framework for distributed Service Function Chains (SFCs). CALVIN classifies VNFs into elementary, basic, and advanced VNFs; moreover, CALVIN implements elementary and basic VNFs in the kernel space, while the advanced VNFs are implemented in the user space. Throughout, CALVIN employs a distributed mapping with one VNF per Virtual Machine (VM) in a MEC system. Furthermore, CALVIN avoids the metadata structure processing and batch processing of packets in the conventional Linux networking stack so as to achieve short per-packet latencies. Our rigorous measurements on off-the-shelf conventional networking and computing hardware demonstrate that CALVIN achieves round-trip times from a MEC ingress point via two elementary forwarding VNFs (one in kernel space and one in user space) and a MEC server to a MEC egress point on the order of 0.32 ms. Our measurements also indicate that MEC network coding and encryption are feasible for small 256 byte packets with an MEC latency budget of 0.35 ms; whereas, large 1400 byte packets can complete the network coding, but not the encryption within the 0.35 ms.

Polarization of Trappist-1 by the Transit of Its Planets

Abstract Being the first, and currently the only, multiple planet hosting dwarf star that is sufficiently cool to form condensate clouds in its atmosphere, Trappist-1 provides a unique opportunity to test the efficiency of image polarimetry as a tool to detect and characterize exoplanets around L- and late M-dwarfs and exomoons around directly imaged self-luminous giant exoplanets. Although scattering of light by atmospheric dust particles should produce a significant amount of linear polarization in the far optical and near infrared, the disk-averaged net detectable polarization of the star must be zero owing to spherical symmetry. However, the transit of its planets would give rise to significant asymmetry and produce phase-dependent polarization with the peak polarization occurring at the inner contact points of planetary transit ingress and egress epochs. Adopting the known stellar and planetary physical parameters and employing a self-consistent cloudy atmosphere model of the M8 dwarf star, the transit polarization profiles and the expected amount of polarization of Trappist-1 during the transit phase of each individual planet, as well as that during the simultaneous transit of two planets, are presented in this paper. It is emphasized that the amount of polarization expected is within the detection limit of a few existing facilities. If polarization is detected confirming the prediction, time-resolved image polarimetry will emerge as a potential tool to detect and characterize small planets around cloudy ultra-cool dwarfs.

Comparative genomics of Pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity.

The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, to replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacteria use chemical-directed regulation of flagellar rotation, a process known as chemotaxis, to move towards favorable environmental conditions. Chemotactic sensing of the plant surface is a potential mechanism through which foliar plant pathogens home in on wounds or stomata, but chemotactic systems in foliar plant pathogens are not well characterized. Comparative genomics of the plant pathogen Pseudomonas syringae pathovar tomato (Pto) implicated annotated chemotaxis genes in the recent adaptations of one Pto lineage. We therefore characterized the chemosensory system of Pto. The Pto genome contains two primary chemotaxis gene clusters, che1 and che2. The che2 cluster is flanked by flagellar biosynthesis genes and similar to the canonical chemotaxis gene clusters of other bacteria based on sequence and synteny. Disruption of the primary phosphorelay kinase gene of the che2 cluster, cheA2, eliminated all swimming and surface motility at 21 °C but not 28 °C for Pto. The che1 cluster is located next to Type IV pili biosynthesis genes but disruption of cheA1 has no observable effect on twitching motility for Pto. Disruption of cheA2 also alters in planta fitness of the pathogen with strains lacking functional cheA2 being less fit in host plants but more fit in a non-host interaction.

The Indian Kattalio Game: mapping the counterfeit currency network in India

Purpose The purpose of this paper is to study the counterfeit currency network in India. This research is an endeavour to bring out various layers which act as source, collection and distribution points in a counterfeit currency network in India. This paper also deals with the fake currency network and its linkages to terrorism. Design/methodology/approach Methodology adopted is a descriptive one which conducts a content analysis on materials derived from secondary sources supported by information from primary source data acquired through the Right to Information Act. Findings This paper argues that the existing measure of calculating the incidence of counterfeit notes per million is understated by the relevant stakeholders in India. This measure changes drastically when other factors such as high denomination notes and police seizures are taken into account, which has not been attempted, though it is duly acknowledged by the stakeholders. This paper has attempted to map the locations in India which act as ingress, distribution and circulation points based on evidentiary data derived from the seizure records. This paper also highlights the fact that criminal gang-operated networks of fake currency are compartmentalised, while the networks operated by terror groups are de-compartmentalised. Practical implications In the process, this paper attempts to enlighten stakeholders like law enforcement agencies, banking regulators and counter terrorism community on the penetration levels of the fake Indian currency note (FICN) networks in India and the need to target these important nodes or points or layers to break up the FICN network. This also highlights fund-raising mechanisms of terror groups, where FICN acts as the main funding resource for groups like the Indian Mujahideen for carrying out low-cost terror attacks. Originality/value The key findings of this research lie in its originality of presentation of facts in a systematic fashion.

Performance Analysis of TCP and its Enhancement for Quality of Service in Mobile Wireless Networks in Single Traffic Using Prioritised Hard Handoff (PH2)

The research activities in mobile computing and wireless networks strongly indicates that mobile computers and their wireless communication links will be an integral part of the current internet works. Communication over wireless links is characterised by limited bandwidth, high latency, high bit-error rates and temporary disconnections. Most often, networks with wireless links and mobile hosts incur significant losses due to handoff. It is also most important that in wireless environment TCP (transmission control protocol) causes degraded end-to-end performance. In this paper, we tried to give solutions to these problems. We adopt a new method to improve the end-to-end reliable transport performance in mobile wireless environment by incorporating changes to network-layer at the base station and mobile host and preserve end-to-end semantics of TCP. The methodology employs NDG (normalised delay gradient) loss-predictor function to determine congestion losses from that of transmission loss. The sender window can adjust its size depending on the loss information. If the loss is due to congestion, congestion control algorithm is invoked to decrease the flow rate. If the loss is due to handoff (transmission loss), immediate-recovery algorithm is invoked to recover the losses caused by the sender TCP. Stochastic equations are used to analyse, i) arrival rate handoff calls, ii) blocking probability of handoff request, iii) distinguish packet loss due to congestion or handoff, iv) dynamics of sender window, v) queue length at the ingress point of the BS router , vi) throughput, and vii) the losses due to congestion and handoff blocking. Our results provide better way understanding the problem of calls drop due to handoff, and providing most accurate solutions for mobile wireless system.

Ground Segment Design for Broadband Geostationary Satellite With Optical Feeder Link

High-data-rate space-to-ground optical links are anticipated to be an alternative to radio-frequency spectrum congestion for the next generation of high-throughput geostationary satellites. An affordable site diversity system based on several optical ground stations (OGSs) and an optical fiber network is necessary to overcome cloud obstruction of the feeder link. In this paper, we report three promising sets of OGSs in the vicinity of existing ingress and egress points of a selected pan-European optical fiber network. These OGS networks are optimized for reaching at least 99.9% feeder link availability while minimizing the overall cost of the system. For the first time, the optical fiber network between OGSs is optimized using existing high-data-rate fiber links to limit its expense. The resulting cost estimates for each OGS network highlight the need to define a new cost model considering optical feeder link specificity. In addition, the link availability is simulated using a 2 year cloud mask data bank, taking into consideration practical cloud blockage forecasting duration and assuming optical transmission through thin ice clouds.

Numerical modeling of liquid waste infiltration from storage facilities into surrounding groundwater and surface water bodies

The study focuses on infiltration of saturated brine from liquid waste storage facilities into the surrounding groundwater and surface water bodies. Storage facilities are located at the Verkhnekamsk Potassium and Magnesium Salt Deposit (Perm Region, Russian Federation) and contain highly mineralized brines of potassium, sodium and magnesium chlorides. Using the analytical solution of one-dimensional equation of contaminant transport by homogeneous stationary filtration flow, we have made estimates of the time it takes the contaminant to move from the storage facilities to the nearest surface water body and a settling time for the stationary concentration profile, neglecting and accounting for contaminant adsorption in the porous matrix. The contaminant concentration at the point of brine ingress into the surface reservoir is calculated. The direct 3D numerical modeling of brine infiltration into the surrounding medium is performed using ANSYS Fluent software package. The modeling results indicate different stages of contaminant propagation in the porous medium. It has been found that the contaminant spreads over a wide area with almost uniform concentration close to the saturation value. The contaminant reaches the nearest riverbed 20 days after the start of infiltration. The numerical results agree well with the analytical results obtained in the framework of the one-dimensional mode. The proposed physical models adequately describe hydrodynamic processes associated with the operation of large storage facilities and can be used to predict contamination propagation in groundwater around the storage facilities.