Switching Center Research Articles

Models of microwave heating of objects

In article models of the microwave oven of heating of objects are considered. One of them represents the generator of the microwave oven of the energy, loaded on the volume resonator in which place heated up object. Other model, along with the microwave oven the generator, contains the switching center with exits on a number of unidirectional radiators in which aperture the irradiated object is established.In article it is considered features of process of interaction of object with a wave guide field. Modes of the minimum rcradiation of energy and the maximum absorption of energy are in detail stated.

Characterization and Development of a Model for the Determination of the Power and Cooling Reliability of a Mobile Switching Centre

Characterization and Development of a Model for the Determination of the Power and Cooling Reliability of a Mobile Switching Centre

Mitigation of the Impact of Cooling System Failure in a Mobile Switching Center Using an Adaptive Controller

Mitigation of the Impact of Cooling System Failure in a Mobile Switching Center Using an Adaptive Controller

Conformational Dynamics and Mechanisms of Client Protein Integration into the Hsp90 Chaperone Controlled by Allosteric Interactions of Regulatory Switches: Perturbation-Based Network Approach for Mutational Profiling of the Hsp90 Binding and Allostery.

Understanding the allosteric mechanisms of the Hsp90 chaperone interactions with cochaperones and client protein clientele is fundamental to dissect activation and regulation of many proteins. In this work, atomistic simulations are combined with perturbation-based approaches and dynamic network modeling for a comparative mutational profiling of the Hsp90 binding and allosteric interaction networks in the three Hsp90 maturation complexes with FKBP51 and P23 cochaperones and the glucocorticoid receptor (GR) client. The conformational dynamics signatures of the Hsp90 complexes and dynamics fluctuation analysis revealed how the intrinsic plasticity of the Hsp90 dimer can be modulated by cochaperones and client proteins to stabilize the closed dimer state required at the maturation stage of the ATPase cycle. In silico deep mutational scanning of the protein residues characterized the hot spots of protein stability and binding affinity in the Hsp90 complexes, showing that binding hot spots may often coincide with the regulatory centers that modulate dynamic allostery in the Hsp90 dimer. We introduce a perturbation-based network approach for mutational scanning of allosteric residue potentials and characterize allosteric switch clusters that control mechanism of cochaperone-dependent client recognition and remodeling by the Hsp90 chaperone. The results revealed a conserved network of allosteric switches in the Hsp90 complexes that allow cochaperones and GR protein to become integrated into the Hsp90 system by anchoring to the conformational switch points in the functional Hsp90 regions. This study suggests that the Hsp90 binding and allostery may operate under a regulatory mechanism in which activation or repression of the Hsp90 activity can be pre-encoded in the allosterically regulated Hsp90 dimer motions. By binding directly to the conformational switch centers on the Hsp90, cochaperones and interacting proteins can efficiently modulate the allosteric interactions and long-range communications required for client remodeling and activation.

Switching Transition Analysis and Optimization for Bidirectional CLLC Resonant DC Transformer

The demand for isolated bidirectional dc transformer (DCX) is driven by the fast development of energy storage system, data center power supply and transportation electrification. Due to zero voltage switching (ZVS) and small rms current, the open-loop CLLC resonant converter operating at the resonant frequency is considered a promising candidate for DCX with a constant voltage transfer ratio. To solve unsmooth bidirectional power flow and current distortion in traditional CLLC-DCX with synchronization rectification (SR) modulation, a dual-active-synchronization (DAS) modulation is adopted with identical driving signals on both sides. Firstly, the switching transition of this modulation is fully analyzed with the consideration of large device output capacitances. After comparison of different transitions, a so-called Sync-ZVS transition is found more desirable with ZVS, no deadtime conduction loss, and load-independent voltage gain. In order to achieve this switching transition, an Axis and Center Symmetric (ACS) method is proposed. Based on this method, an overall design procedure of CLLC-DCX with DAS modulation is also proposed. Finally, Sync-ZVS transition and the proposed ACS method are both verified by three 18 kW 500 kHz prototypes with a 98.8% peak efficiency. This article is accompanied by one video demonstrating the load changing test.

METHODS FOR ENSURING DATA SECURITY IN MOBILE STANDARDS

The analysis of mobile communication standards is carried out, the functional structure and interfaces of interaction between the structural elements of the cellular network are considered. To understand the principle of communication according to the GSM standard, a block diagram of a mobile switching center (MSC), base station equipment (BSS), control and service center (MCC), mobile stations (MS) is presented. The main algorithms for ensuring the confidentiality and security of mobile subscribers' data, in different types of standards, as well as the vulnerabilities of information flows are considered. In particular, the following dangerous types of attacks have been identified, to which mobile network subscribers are sensitive: sniffing; leakage of personal data; leakage of geolocation data; spoofing; remote capture of SIM-card, execution of arbitrary code (RCE); denial of service (DoS). It is established that the necessary function of the mobile network is the identification of subscribers, which is performed by IMSI, which is recorded in the SIM card of the subscriber and the HLR of the operator. To protect against spoofing, the network authenticates the subscriber before starting its service. In the case of subscriber identification, the subscriber and the network operator are protected from the effects of fraudulent access. In addition, the user must be protected from eavesdropping. This is achieved by encrypting the data transmitted over the radio interface. Thus, user authentication in UMTS, as well as in the GSM network, is carried out using encryption with a common key using the "hack-response" protocol (the authenticating party sends a random number to the authenticated party, which encrypts it according to a certain algorithm using a common key and returns the result back).

Exploring Mechanisms of Allosteric Regulation and Communication Switching in the Multiprotein Regulatory Complexes of the Hsp90 Chaperone with Cochaperones and Client Proteins: Atomistic Insights from Integrative Biophysical Modeling and Network Analysis of Conformational Landscapes

Understanding molecular principles underlying Hsp90 chaperone functions and modulation of client activity is fundamental to dissect activation mechanisms of many proteins. In this work, we performed a computational investigation of the Hsp90-Hsp70-Hop-CR client complex to examine allosteric regulatory mechanisms underlying dynamic chaperone interactions and principles of chaperone-dependent client recognition and remodeling. Conformational dynamics analysis using high-resolution coarse-grained simulations and ensemble-based local frustration analysis suggest that the Hsp90 chaperone could recognize and recruit the GR client by invoking reciprocal dynamic exchanges near the intermolecular interfaces with the client. Using mutational scanning of the intermolecular residues in the Hsp90-Hsp70-Hop-GR complex, we identified binding energy hotspots in the regulatory complex. Perturbation-based network analysis and dynamic fluctuations-based modeling of allosteric residue potentials are employed for a detailed analysis of allosteric interaction networks and identification of conformational communication switches. We found that allosteric interactions between the Hsp90, the client-bound Hsp70 and Hop cochaperone can define two allosteric residue clusters that control client recruitment in which the intrinsic Hsp70 allostery is exploited to mediate integration of the Hsp70-bound client into the Hsp90 chaperone system. The results suggest a model of dynamics-driven allostery that enables efficient client recruitment and loading through allosteric couplings between intermolecular interfaces and communication switch centers. This study showed that the Hsp90 interactions with client proteins may operate under dynamic-based allostery in which ensembles of preexisting conformational states and intrinsic allosteric pathways present in the Hsp90 and Hsp70 chaperones can be exploited for recognition and integration of substrate proteins.

Effect of Backhaul Technologies on 3G Network Performance: A Case Study of Ado-Ekiti

In the past years, when wireless network improvement occurs from 1G/2G to third generation (3G), the rate in the use of real-time traffic oriented applications for voice, video and data increases. Consequently, the bandwidth to be backhauled from the cell site to the mobile switching center increases rapidly. 3G network is most prevalent in Nigeria with wide area of coverage. However, in recent times, poor subscribers’ mobile broadband experience is still the major challenge faced by many GSM operators. One of the major causes of this challenge is the use of wrong backhaul for radio access network (RAN). This lead to poor traffic throughput, high packet loss or frame loss at the cell edge. To overcome this challenge, the use of appropriate backhaul technology is crucial. Third Generation Partnership Program (3GPP) recommends the use of either asynchronous transfer mode (ATM) or internet protocol (IP) as the backhaul technologies for its RAN. This paper presents the performance analysis and the comparison of the ATM RAN and IP RAN backhaul technologies using six different 3G sites (with 3G base stations) located at Ado local government area of Ekiti State, Nigeria. The performance of each base station with different backhaul technology was evaluated in term of average maximum throughput per day. The effect of frame loss (for ATM RAN network) and packet loss (for IP RAN network) on traffic throughput were also analyzed. The comparison of the overall result analysis shows that the 3G base stations with IP-based RAN backhaul has better performance than the base station with ATM-based RAN backhaul.

Система обмена данными как образец системного подхода к созданию крупных информационных систем

The article is devoted to historical aspects of the first domestic data exchange system (DES) creation with packet switching. The role and place of this system as part of an interspecific automated control system for strategic purposes are shown. There is considered systemic and organizational background for the construction of DES on the basis of message switching centers. The experience of creating ARPANET, the network with packet switching is presented. It is noted that the creation of DES was the result of joint efforts of ordering bodies of the USSR Defense Ministry, a leading industrial enterprise - the Scientific Research Institute of Automatic Equipment, as well as military scientific organizations, particularly the 16th Central Research Institute of Communications.

Comprehensive model for technoeconomic studies of next-generation central offices for metro networks

This paper introduces a novel and simplified cost model for designing and evaluating a Central Office Rearchitected as a Datacenter (CORD). The model includes equipment and elements for the realization of optical, packet switching, and data center parts with a special focus not only on relative costs but also on power consumption figures. The cost model is then applied to the design and comparison of a metropolitan area network (MAN) including both aggregation and metrocore nodes following several MAN node architectures based on CORD-like leaf-and-spine fabric. In particular, equipment disaggregation at the Central Offices, both on the packet-switching and optical components, can provide important cost savings to telco operators. On the other hand, incorporating computing/storage capabilities in the MAN for the realization of multiaccess edge computing (MEC) has a significant impact on the total network cost but especially on power consumption.

THE TASK OF CHOOSING A RELIABLE PATH FOR MESSAGE TRANSMISSION IN A COMPUTER NETWORK

The article provides a calculation and comparative analysis of the reliability and productivity of computer systems in a positional binary number system and in a non-positional number system in residual classes (residual number system – RNS), for calculations and comparative we consider practical task. The main goal is to solve the task of choosing a reliable path for message transmission in a computer network. Calculation and comparative evaluation of the reliability and performance of the computer system in the RNS and the existing in the positional binary number system computer system APO-221 of the product 15E1235 (automatic message switching center - ASC) when solving the basic task of the ASC – the task of choosing the transmission path of a formalized message (path selection algorithm (PSA))

Solving the p-median problem on regular and lattice networks

The p-median problem is one of the true classic problems of location science and has been applied in many ways. It involves the location of p-facilities on a network where the objective is to minimize the weighted distance of serving all demand. This problem was originally proposed by Hakimi (1964, 1965) where the facilities were telephone switching centers and the connections represent wire stretched between each customer and their closest facility. It has since been viewed as the quintessential public facility location problem as it involves placing facilities as close to as possible on the average to each demand. This problem was originally formulated as an integer-programming problem by ReVelle and Swain (1970). Their formulation has withstood the test of time as most of the approaches to optimally solve the p-median problem involve a form of this model. There are several notable exceptions to the use of the classical formulation which take advantage of the underlying distance matrix defined by regular networks (Elloumi 2010; García et al., 2011), such as grid-defined networks. We demonstrate that inherent properties of the distance matrix defined for regular networks can be taken into account, resulting in a reduced, frugal form of the classic p-median model of ReVelle and Swain (1970). This new model called CARS is tested and compared to a form of the original model, recent computational experience presented by Daskin and Maass (2015) and to a form of the model used by García et al. (2011). This test demonstrates that this new, simple model is very competitive to other approaches in solving sizable p-median problems using off-the-shelf commercial software.

Artificial intelligence‐based novel scheme for location area planning in cellular networks

AbstractPlanning of location area (LA) in cellular networks plays a vital role in utilizing the resources efficiently and economically. Location update and paging costs directly affect the cost to the service provider. When the size of the Mobile Switching Centre (MSC) is large, the paging cost becomes maximum. Though, no location update is required for this case. On the contrary, paging cost shoots high if each cell forms individual LA, but in this case, location update cost shoots to the maximum value. Therefore, deducing the network to the optimal amount of LA's is an intractable combinatorial optimization problem. In this paper, we intend to optimize the partitions of the MSC service area into an optimal number of LA, to curtail the total location management cost. We propose a novel scheme bearing in mind cell attributes of the network to deduce an optimum number of location areas, leading to minimum cost per call. It is revealed by the results of this work, attained after simulating the scenario on MATLAB 2018a that Cell Attributes Based Algorithm is a very promising scheme for cellular networks, and it outperforms the existing algorithms in a practical scenario.

Allosteric Mechanism of the Hsp90 Chaperone Interactions with Cochaperones and Client Proteins by Modulating Communication Spines of Coupled Regulatory Switches: Integrative Atomistic Modeling of Hsp90 Signaling in Dynamic Interaction Networks.

Conformational landscapes of the Hsp90 chaperones have revealed that the intrinsic plasticity and functional adaptability of these molecular chaperones to a large cohort of cochaperones and a vast protein clientele can be regulated by a number of single switch points broadly dispersed in the chaperone structure. A detailed dynamic view of the allosteric changes mediated by conformational switches and the mechanism of their coupling during the ATPase cycle remains poorly understood and presents an important area of investigation. In this work, we employed integrative computational modeling that included evolutionary and coevolutionary analyses, experiment-guided protein docking and structure modeling, molecular simulations, energetic analysis, and network modeling to perform a systematic characterization of molecular and network signatures of conformational switch points and dissect their allosteric cross-talk in the Hsp90 complexes with cochaperones and client proteins. Using a hierarchical modeling of dynamic interaction networks, we show that the allosteric regulation of the Hsp90 interactions with p23 and Aha1 cochaperones and p53 client protein may be determined by the intramolecular communication "spines" of spatially separated and allosterically coupled regulatory switches. Using a battery of computational approaches, we examined how p23, Aha1, and p53 proteins can modulate signal transmission in the Hsp90 by exploiting communication spines of regulatory switches in the global allosteric network. This study proposes a community-chain mechanism of allosteric coupling between conformational switch centers and identifies key regulatory control points that mediate long-range interactions and communications in the Hsp90 chaperone. The results of this investigation provide novel insights into the nature of allosteric regulation mechanisms in the Hsp90 chaperones and offer a simple mechanistic model of the Hsp90 communications and adaptation to binding partners during the functional cycle.

First-in-human clinical trial to assess pharmacokinetics, pharmacodynamics, safety, and tolerability of iscalimab, an anti-CD40 monoclonal antibody.

Iscalimab is a fully human, CD40 pathway blocking, nondepleting monoclonal antibody being developed as an immunosuppressive agent. We describe a first-in-human, randomized, double-blind, placebo-controlled study investigating the safety, tolerability, pharmacokinetics, and pharmacodynamics of iscalimab in healthy subjects and rheumatoid arthritis patients. Healthy subjects (n=56) received single doses of intravenous iscalimab (0.03, 0.1, 0.3, 1, or 3mg/kg), or subcutaneous iscalimab (3mg/kg), or placebo. Rheumatoid arthritis patients (n=20) received single doses of intravenous iscalimab (10 or 30mg/kg) or placebo. Iscalimab exhibited target-mediated drug disposition resulting in dose-dependent and nonlinear pharmacokinetics. Complete (≥90%) CD40 receptor occupancy on whole blood B cells was observed at plasma concentrations >0.3-0.4µg/mL. In subjects receiving 3mg/kg iscalimab, antibody responses to keyhole limpet hemocyanin were transiently suppressed. CD40 occupancy by iscalimab prevented ex vivo human rCD154-induced expression of CD69 on B cells in whole blood. All doses were generally safe and well tolerated, with no clinically relevant changes in any safety parameters, including no evidence of thromboembolic events. Iscalimab appears to be a promising blocker of the CD40-CD154 costimulatory pathway with potential use in transplantation and other autoimmune diseases.

COMPARISON OF THREE DIFFERENT EOU TECHNIQUES FOR FIFTH−GENERATION MM−W WIRELESS NETWORKS

Fifth−generation (5G) and millimeter−waves (MM−W) hold tremendous promise to provide opportunities torevolutionize education, healthcare, business, and agriculture.Nevertheless, the generation of MM−W in the electrical−domain is infeasible due to the bandwidth limitation of electronic componentsand radio frequency (RF) interference. The capability to generate MM−W in the optical−domain can provide transportation ofMM−W with low loss from switching center to remote base stations. The present paper is focusing on electro−opticalup−conversion (EOU) techniques for optical generation and transmission of 60−GHz MM−W signal. A comparative study iscarried out between three different EOU techniques: frequency−quadrupling, frequency sextupling and frequency−octotupling. The comparative study aims at showing the strengths and weaknesses of three EOU techniques and evaluatingeach technique in terms of electrical spurious suppression ratio (ESSR), as well as in terms of the influence of non−ideal phaseshifting. The performance of the three EOU techniques after transmission over optical fiber is evaluated by eye pattern test. Theresults of the simulation confirm that the frequency−quadrupling outperforms frequency− sextupling and frequency− octotuplingtechniques.

A two-level facility location and sizing problem for maximal coverage

This paper presents a two-stage hierarchical location problem for systems where the lower level facilities act as the first points contact for the customers while the upper level facilities act as suppliers of the lower level facilities that either serve them or provide advanced services to customers. Furthermore, more recent and realistic coverage constructs such as gradual and cooperative covering are included in our setting. Although our problem can be applicable in various settings, the most fitting application is in wireless telecommunication networks to determine the location of base stations and mobile switching centers. We have developed two competing formulations for the problem, each of which involve nonlinear components that are difficult to deal with. We then develop their respective linearizations and tested their performances. These formulations are solved by commercial optimizers for a set of reasonably large problem instances and it is found that majority of the problems can be solved within a maximum of 10% optimality gap within a short time.

Atomistic Modeling of the ABL Kinase Regulation by Allosteric Modulators Using Structural Perturbation Analysis and Community-Based Network Reconstruction of Allosteric Communications.

In this work, we have examined the molecular mechanisms of allosteric regulation of the ABL tyrosine kinase at the atomic level. Atomistic modeling of the ABL complexes with a panel of allosteric modulators has been performed using a combination of molecular dynamics simulations, structural residue perturbation scanning, and a novel community analysis of the residue interaction networks. Our results have indicated that allosteric inhibitors and activators may exert a differential control on allosteric signaling between the kinase binding sites and functional regions. While the inhibitor binding can strengthen the closed ABL state and induce allosteric communications directed from the allosteric pocket to the ATP binding site, the DPH activator may induce a more dynamic open form and activate allosteric couplings between the ATP and substrate binding sites. By leveraging a network-centric theoretical framework, we have introduced a novel community analysis method and global topological parameters that have unveiled the hierarchical modularity and the intercommunity bridging sites in the residue interaction network. We have found that allosteric functional hotspots responsible for the kinase regulation may serve the intermodular bridges in the global interaction network. The central conclusion from this analysis is that the regulatory switch centers play a fundamental role in the modular network organization of ABL as the unique intercommunity bridges that connect the SH2 and SH3 domains with the catalytic core into a functional kinase assembly. The hierarchy of network organization in the ABL regulatory complexes may allow for the synergistic action of dense intercommunity links required for the robust signal transfer in the catalytic core and sparse network bridges acting as the regulatory control points that orchestrate allosteric transitions between the inhibited and active kinase forms.

RADIO RELAY STATIONS WITH IMPROVED CHARACTERISTICS

Despite the variety of modern means of communication, radio relay lines of information are not lost due to the possibility of their creation in hard-to-reach mountain regions and in conditions of dense development of large cities. One-way radio relay lines have been widely used to transmit information between the central office and branches of the enterprise in corporate networks, between base stations and switching center in mobile communication networks, between military structures for operational management, in emergency situations. When creating radio relay links, the basic tasks are to use the minimum possible transmitter power sufficient to ensure the required quality of information transmission. At the same time minimum influence of electromagnetic radiation on health of people in the area of station operation, better electromagnetic compatibility of equipment with equipment of neighboring regions, duration of station operation at power supply from accumulator battery are achieved. In this paper are reviewed the methods to improve the energy, noise immunity and confidential microwave link using the 4-way signal of PM-4. The advantages of microwave links with noise-like signals generated using pseudorandom sequences based on chaos are shown here.

Analysis of Corporate Dividend Declaration of Telecom Firms in India

The Telecom Sector of an emergent country like India is mounting after liberalization at a incessant pace and has taken the place of second major network in the world. Main sectors of the Indian telecommunication industry are telephony, Internet and television broadcast Industry in the nation that is in an ongoing procedure of relocating into next generation network, employs a widespread system of modern network fundamentals such as digital telephone exchanges, mobile switching centers, media gateways and signaling gateways at the core, interconnected by an extensive variety of transmission systems with fiber-optics or Microwave radio relay networks. These innovations which are taking place in the given sector and are serving the sector to create as a brand of India in the world. The given learning is examining the influence of these innovations in the telecom sector, which can be evidenced by glancing at the association and consequence of dividend policy on the share prices of particular Indian companies. The companies assumed for study are Reliance Communications, Bharti Airtel, MTNL and Tata Communications.T- Test is used for data analysis using SPSS and MS-EXCEL as a tool.